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https://en.wikipedia.org/wiki/BrickOS
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brickOS is an open-source operating system created by Markus Noga as firmware to operate as an alternative software environment for the Lego Mindstorms Robotic Invention System [14]. brickOS is the first open-source software made for Lego Mindstorms robots. It is embedded with a C/C++-based and a Java-based environment for RCX program through utilizing g++ and jack toolchain. It uses a Hitachi H8 cross compiler assembler as its primary toolchain.
The operating system comprises demonstration programs implemented in C and C++ and an alternative operating system for the Lego Mindstorms. It provides users with utilities that allows them to download compiled programs and install the operating system for RCX.
Features
BrickOS was designed and developed using Linux as a replacement for the previous operating system for Lego Mindstorms, which is also known as LegOS. It is capable of being implemented on the Windows system and most Unices [6]. It allows for a more flexible and higher performances system that is much superior to LegOS [3]. The current version of the system's main features includes [3]:
BrickOS programs are executed natively instead of interpreted bytes code [12] like that of a standard firmware which in terms makes the program faster. BrickOS is flexible with controlling outputs [2], for instance, it can alter 255 value of motor speed. Another feature is that brickOS contains a LegOS Network Protocol (LNP) which allows for more than one driver to communicate. This protocol will broadcast message to any RCXs component within the receiving area. By adding layers to the command, the message can filter out the recipient to arrive at the addressed RCX.
BrickOS provides a development environment that allows users to freely implement the provided RCX drivers, such as sensors and motors, using C or C++ programming languages. It can be used alongside libre simulators LegoSim and Emmulegos, which provide graphical interfaces to create a virtual machine that eases t
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https://en.wikipedia.org/wiki/Prototype%20Verification%20System
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The Prototype Verification System (PVS) is a specification language integrated with support tools and an automated theorem prover, developed at the Computer Science Laboratory of SRI International in Menlo Park, California.
PVS is based on a kernel consisting of an extension of Church's theory of types with dependent types, and is fundamentally a classical typed higher-order logic. The base types include uninterpreted types that may be introduced by the user, and built-in types such as the booleans, integers, reals, and the ordinals. Type-constructors include functions, sets, tuples, records, enumerations, and abstract data types. Predicate subtypes and dependent types can be used to introduce constraints; these constrained types may incur proof obligations (called type-correctness conditions or TCCs) during typechecking. PVS specifications are organized into parameterized theories.
The system is implemented in Common Lisp, and is released under the GNU General Public License (GPL).
See also
Formal methods
List of proof assistants
References
Owre, Shankar, and Rushby, 1992. PVS: A Prototype Verification System. Published in the CADE 11 conference proceedings.
External links
PVS website at SRI International's Computer Science Laboratory
Summary of PVS by John Rushby at the Mechanized Reasoning database of Michael Kohlhase and Carolyn Talcott
Formal specification languages
Proof assistants
Dependently typed languages
Lisp (programming language)
Common Lisp (programming language) software
Free theorem provers
Free software programmed in Lisp
SRI International software
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https://en.wikipedia.org/wiki/Heat%20sealer
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A heat sealer is a machine used to seal products, packaging, and other thermoplastic materials using heat. This can be with uniform thermoplastic monolayers or with materials having several layers, at least one being thermoplastic. Heat sealing can join two similar materials together or can join dissimilar materials, one of which has a thermoplastic layer.
Process
Heat sealing is the process of sealing one thermoplastic to another similar thermoplastic using heat and pressure.
The direct contact method of heat sealing utilizes a constantly heated die or sealing bar to apply heat to a specific contact area or path to seal or weld the thermoplastics together. Heat sealing is used for many applications, including heat seal connectors, thermally activated adhesives, film media, plastic ports or foil sealing.
Applications
Heat seal connectors are used to join LCDs to PCBs in many consumer electronics, as well as in medical and telecommunication devices.
Heat sealing of products with thermal adhesives is used to hold clear display screens onto consumer electronic products and for other sealed thermo-plastic assemblies or devices where heat staking or ultrasonic welding are not an option due to part design requirements or other assembly considerations.
Heat sealing also is used in the manufacturing of bloodtest film and filter media for the blood, virus and many other test strip devices used in the medical field today. Laminate foils and films often are heat sealed over the top of thermoplastic medical trays, Microtiter (microwell) plates, bottles and containers to seal and/or prevent contamination for medical test devices, sample collection trays and containers used for food products.
Plastic bags and other packaging is often formed and sealed by heat sealers. Medical and fluid bags used in the medical, bioengineering and food industries. Fluid bags are made out of a multitude of varying materials such as foils, filter media, thermoplastics and laminates.
Types of
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https://en.wikipedia.org/wiki/0.999...
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In mathematics, 0.999... (also written as 0., 0. or 0.(9)) is a notation for the repeating decimal consisting of an unending sequence of 9s after the decimal point. This repeating decimal is a numeral that represents the smallest number no less than every number in the sequence (0.9, 0.99, 0.999, ...); that is, the supremum of this sequence. This number is equal to1. In other words, "0.999..." is not "almost exactly" or "very, very nearly but not quite" rather, "0.999..." and "1" represent the same number.
There are many ways of showing this equality, from intuitive arguments to mathematically rigorous proofs. The technique used depends on the target audience, background assumptions, historical context, and preferred development of the real numbers, the system within which 0.999... is commonly defined. In other systems, 0.999... can have the same meaning, a different definition, or be undefined.
More generally, every nonzero terminating decimal has two equal representations (for example, 8.32 and 8.31999...), which is a property of all positional numeral system representations regardless of base. The utilitarian preference for the terminating decimal representation contributes to the misconception that it is the only representation. For this and other reasons—such as rigorous proofs relying on non-elementary techniques, properties, or disciplines—some people can find the equality sufficiently counterintuitive that they question or reject it. This has been the subject of several studies in mathematics education.
Elementary proof
There is an elementary proof of the equation , which uses just the mathematical tools of comparison and addition of (finite) decimal numbers, without any reference to more advanced topics such as series, limits, formal construction of real numbers, etc. The proof, given below, is a direct formalization of the intuitive fact that, if one draws 0.9, 0.99, 0.999, etc. on the number line there is no room left for placing a number between
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https://en.wikipedia.org/wiki/Epson%20QX-10
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The Epson QX-10 is a microcomputer running CP/M or TPM-III (CP/M-80 compatible) which was introduced in 1983. It was based on a Zilog Z80 microprocessor, running at 4 MHz, provided up to 256 KB of RAM organized in four switchable banks, and included a separate graphics processor chip (µPD7220) manufactured by NEC to provide advanced graphics capabilities. In the USA and Canada, two versions were launched; a basic CP/M configuration with 64 KB RAM and the HASCI configuration with 256 KB RAM and the special HASCI keyboard to be used with the bundled application suite, called Valdocs. TPM-III was used for Valdocs and some copy protected programs like Logo Professor. The European and Japanese versions were CP/M configurations with 256 KB RAM and a graphical Basic interpreter.
The machine had internal extension slots, which could be used for extra serial ports, network cards or third party extensions like an Intel 8088 processor, adding MS-DOS compatibility.
Rising Star Industries was the primary American software vendor for the HASCI QX series. Their product line included the TPM-II and III operating system, Valdocs, a robust BASIC language implementation, a graphics API library used by a variety of products which initially supported line drawing and fill functions and was later extended to support the QX-16 color boards, Z80 assembler, and low level Zapple machine code monitor which could be invoked from DIP switch setting on the rear of the machine.
QX-11
The "Abacus" is a IBM PC compatible machine released in 1985 booting MS-DOS 2.11 from 64 KB ROM. It has a Intel 8086-2 CPU at 8 MHz, 128 to 512 KB of RAM and two 3½" floppy drives (360 KB format). The sound chip has 3 sound tones plus one noise channel with 16 independent volume levels, graphics are 640x400 and the joystick ports are Atari-2600 compatible. There was also support for custom ROM cartridges.
QX-16
Its successor, the dual-processor QX-16, added a 16-bit Intel processor with Color Graphics Adapter
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https://en.wikipedia.org/wiki/Modified%20atmosphere
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Modified atmosphere packaging (MAP) is the practice of modifying the composition of the internal atmosphere of a package (commonly food packages, drugs, etc.) in order to improve the shelf life. The need for this technology for food arises from the short shelf life of food products such as meat, fish, poultry, and dairy in the presence of oxygen. In food, oxygen is readily available for lipid oxidation reactions. Oxygen also helps maintain high respiration rates of fresh produce, which contribute to shortened shelf life. From a microbiological aspect, oxygen encourages the growth of aerobic spoilage microorganisms. Therefore, the reduction of oxygen and its replacement with other gases can reduce or delay oxidation reactions and microbiological spoilage. Oxygen scavengers may also be used to reduce browning due to lipid oxidation by halting the auto-oxidative chemical process. Besides, MAP changes the gaseous atmosphere by incorporating different compositions of gases.
The modification process generally lowers the amount of oxygen (O2) in the headspace of the package. Oxygen can be replaced with nitrogen (N2), a comparatively inert gas, or carbon dioxide (CO2).
A stable atmosphere of gases inside the packaging can be achieved using active techniques, such as gas flushing and compensated vacuum, or passively by designing “breathable” films.
History
The first recorded beneficial effects of using modified atmosphere date back to 1821. Jacques Étienne Bérard, a professor at the School of Pharmacy in Montpellier, France, reported delayed ripening of fruit and increased shelf life in low-oxygen storage conditions. Controlled atmosphere storage (CAS) was used from the 1930s when ships transporting fresh apples and pears had high levels of CO2 in their holding rooms in order to increase the shelf life of the product. In the 1970s MA packages reached the stores when bacon and fish were sold in retail packs in Mexico. Since then development has been continuous and interes
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https://en.wikipedia.org/wiki/Neurosarcoidosis
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Neurosarcoidosis (sometimes shortened to neurosarcoid) refers to a type of sarcoidosis, a condition of unknown cause featuring granulomas in various tissues, in this type involving the central nervous system (brain and spinal cord). Neurosarcoidosis can have many manifestations, but abnormalities of the cranial nerves (a group of twelve nerves supplying the head and neck area) are the most common. It may develop acutely, subacutely, and chronically. Approximately 5–10 percent of people with sarcoidosis of other organs (e.g. lung) develop central nervous system involvement. Only 1 percent of people with sarcoidosis will have neurosarcoidosis alone without involvement of any other organs. Diagnosis can be difficult, with no test apart from biopsy achieving a high accuracy rate. Treatment is with immunosuppression. The first case of sarcoidosis involving the nervous system was reported in 1905.
Signs and symptoms
Neurological
Abnormalities of the cranial nerves are present in 50–70 percent of cases. The most common abnormality is involvement of the facial nerve, which may lead to reduced power on one or both sides of the face (65 percent resp 35 percent of all cranial nerve cases), followed by reduction in visual perception due to optic nerve involvement. Rarer symptoms are double vision (oculomotor nerve, trochlear nerve or abducens nerve), decreased sensation of the face (trigeminal nerve), hearing loss or vertigo (vestibulocochlear nerve), swallowing problems (glossopharyngeal nerve) and weakness of the shoulder muscles (accessory nerve) or the tongue (hypoglossal nerve). Visual problems may also be the result of papilledema (swelling of the optic disc) due to obstruction by granulomas of the normal cerebrospinal fluid (CSF) circulation.
Seizures (mostly of the tonic-clonic/"grand mal" type) are present in about 15 percent and may be the presenting phenomenon in 10 percent.
Meningitis (inflammation of the lining of the brain) occurs in 3–26 percent of cases. Sym
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https://en.wikipedia.org/wiki/Virtual%20Private%20LAN%20Service
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Virtual Private LAN Service (VPLS) is a way to provide Ethernet-based multipoint to multipoint communication over IP or MPLS networks. It allows geographically dispersed sites to share an Ethernet broadcast domain by connecting sites through pseudowires. The term sites includes multiplicities of both servers and clients. The technologies that can be used as pseudo-wire can be Ethernet over MPLS, L2TPv3 or even GRE. There are two IETF standards-track RFCs (RFC 4761 and RFC 4762) describing VPLS establishment.
VPLS is a virtual private network (VPN) technology. In contrast to L2TPv3, which allows only point-to-point layer 2 tunnels, VPLS allows any-to-any (multipoint) connectivity.
In a VPLS, the local area network (LAN) at each site is extended to the edge of the provider network. The provider network then emulates a switch or bridge to connect all of the customer LANs to create a single bridged LAN.
VPLS is designed for applications that require multipoint or broadcast access.
Mesh establishment
Since VPLS emulates a LAN, full mesh connectivity is required. There are two methods for full mesh establishment for VPLS: using Border Gateway Protocol (BGP) and using Label Distribution Protocol (LDP). The "control plane" is the means by which provider edge (PE) routers communicate for auto-discovery and signalling. Auto-discovery refers to the process of finding other PE routers participating in the same VPN or VPLS. Signalling is the process of establishing pseudowires (PW). The PWs constitute the "data plane", whereby PEs send customer VPN/VPLS traffic to other PEs.
BGP provides both auto-discovery and signalling. The mechanisms used are very similar to those used in establishing Layer-3 MPLS VPNs. Each PE is configured to participate in a given VPLS. The PE, through the use of BGP, simultaneously discovers all other PEs in the same VPLS, and establishes a full mesh of pseudowires to those PEs.
With LDP, each PE router must be configured to participate in
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https://en.wikipedia.org/wiki/Dyck%20language
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In the theory of formal languages of computer science, mathematics, and linguistics, a Dyck word is a balanced string of brackets.
The set of Dyck words forms a Dyck language. The simplest, D1, use just two matching brackets, e.g. ( and ).
Dyck words and language are named after the mathematician Walther von Dyck. They have applications in the parsing of expressions that must have a correctly nested sequence of brackets, such as arithmetic or algebraic expressions.
Formal definition
Let be the alphabet consisting of the symbols [ and ]. Let denote its Kleene closure.
The Dyck language is defined as:
Context-free grammar
It may be helpful to define the Dyck language via a context-free grammar in some situations.
The Dyck language is generated by the context-free grammar with a single non-terminal , and the production:
That is, S is either the empty string () or is "[", an element of the Dyck language, the matching "]", and an element of the Dyck language.
An alternative context-free grammar for the Dyck language is given by the production:
That is, S is zero or more occurrences of the combination of "[", an element of the Dyck language, and a matching "]", where multiple elements of the Dyck language on the right side of the production are free to differ from each other.
Alternative definition
In yet other contexts it may instead be helpful to define the Dyck language by splitting into equivalence classes, as follows.
For any element of length , we define partial functions and by
is with "" inserted into the th position
is with "" deleted from the th position
with the understanding that is undefined for and is undefined if . We define an equivalence relation on as follows: for elements we have if and only if there exists a sequence of zero or more applications of the and functions starting with and ending with . That the sequence of zero operations is allowed accounts for the reflexivity of . Symmetry follows from the observation
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https://en.wikipedia.org/wiki/Reynolds%20stress
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In fluid dynamics, the Reynolds stress is the component of the total stress tensor in a fluid obtained from the averaging operation over the Navier–Stokes equations to account for turbulent fluctuations in fluid momentum.
Definition
The velocity field of a flow can be split into a mean part and a fluctuating part using Reynolds decomposition. We write
with being the flow velocity vector having components in the coordinate direction (with denoting the components of the coordinate vector ). The mean velocities are determined by either time averaging, spatial averaging or ensemble averaging, depending on the flow under study. Further denotes the fluctuating (turbulence) part of the velocity.
We consider a homogeneous fluid, whose density ρ is taken to be a constant. For such a fluid, the components τ'''ij of the Reynolds stress tensor are defined as:
Another – often used – definition, for constant density, of the Reynolds stress components is:
which has the dimensions of velocity squared, instead of stress.
Averaging and the Reynolds stress
To illustrate, Cartesian vector index notation is used. For simplicity, consider an incompressible fluid:
Given the fluid velocity as a function of position and time, write the average fluid velocity as , and the velocity fluctuation is . Then .
The conventional ensemble rules of averaging are that
One splits the Euler equations (fluid dynamics) or the Navier-Stokes equations into an average and a fluctuating part. One finds that upon averaging the fluid equations, a stress on the right hand side appears of the form . This is the Reynolds stress, conventionally written :
The divergence of this stress is the force density on the fluid due to the turbulent fluctuations.
Reynolds averaging of the Navier–Stokes equations
For instance, for an incompressible, viscous, Newtonian fluid, the continuity and momentum equations—the incompressible Navier–Stokes equations—can be written (in a non-conservative form) as
and
wh
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https://en.wikipedia.org/wiki/LightScribe
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LightScribe is an optical disc recording technology that was created by the Hewlett-Packard Company. It uses specially coated recordable CD and DVD media to produce laser-etched labels with text or graphics, as opposed to stick-on labels and printable discs. Although HP is no longer developing the technology, it is still maintained and supported by a number of independent enthusiasts.
The LightScribe method uses the laser in a way similar to when plain data are written to the disc; a greyscale image of the label is etched (physically burned) onto the upper side of the disc using a laser. In the beginning, the discs were available only in a sepia color but later became available in many monochromatic colors.
The purpose of LightScribe is to allow users to create direct-to-disc labels (as opposed to stick-on labels), using their optical disc writer. Special discs and a compatible disc writer are required. Before or after burning data to the read-side of the disc, the user turns the disc over and inserts it with the label side down. The drive's laser then burns the label side in such a way that an image is produced. (see Thermal printing; LightScribe uses a laser instead of a thermal printing head)
History
LightScribe was conceived by Hewlett-Packard engineer Daryl Anderson, and the coating's chemistry was developed by Dr. Makarand Gore, and brought to market through the joint design efforts of HP's imaging and optical storage divisions, where it was first introduced in January 2004 at the 2004 Consumer Electronics Show.
It was the first direct to disc labeling technology that allowed users to laser etch images to the label side of a disc. DiscT@2 technology had been on the market since 2002, but DiscT@2 allows users to burn only to the unused portion of the data side of the disc. In 2005, LabelFlash became the main competitor for LightScribe.
Various brands manufacture the required media. Dual Layer DVD+Rs are the highest-capacity disc to support the technology.
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https://en.wikipedia.org/wiki/Adventure%20Island%20%28video%20game%29
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Hudson's Adventure Island, known as in Japan and also known as Adventure Island, is a side-scrolling platform game produced by Hudson Soft that was released in Japan for the Famicom and MSX on September 12, 1986. Adventure Island was released in North America for the Nintendo Entertainment System in 1988 and in the PAL region in 1992.
Adventure Island is an adaptation of the arcade game Wonder Boy, developed by Escape for Sega. Adventure Island was followed by a series of sequels with no connection to the Wonder Boy series.
Plot
The player controls Master Higgins (known as Master Wigins in the United Kingdom and as Takahashi Meijin in Japanese versions), a young man who ventured to Adventure Island in the South Pacific after hearing that the Evil Witch Doctor kidnapped Princess Tina. To rescue her, Higgins must survive a series of 32 stages. There are eight worlds called "areas", which are divided into four stages or "rounds" each, which are further divided into four checkpoints. When the player reaches the fourth round of each area, he must confront a boss at the end to continue to the next area. The game is completed when the player saves the girl after defeating the eighth and final form of the evil lord.
Gameplay
Master Higgins (the player character) loses a life whenever he touches an enemy, an enemy's attack, a fire roast, or when he falls into a pitfall or a body of water. The player also has a health gauge that starts out with 11 points, which gradually depletes over time or whenever Higgins trips on a rock in his path. When Higgins' health gauge reaches zero, he will lose a life. If Higgins still has extra lives, he will revive at the last checkpoint he passed through. The game ends when all of Higgins' lives run out. To replenish his health, Higgins can pick up fruit or a milk bottle and has a maximum health of up to 16 points. When the player's score reaches 50,000 points, 100,000 points, and 200,000 points, Higgins will receive an extra life. Findin
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https://en.wikipedia.org/wiki/Complementary%20currency
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A complementary currency is a currency or medium of exchange that is not necessarily a national currency, but that is thought of as supplementing or complementing national currencies. Complementary currencies are usually not legal tender and their use is based on agreement between the parties exchanging the currency. According to Jérôme Blanc of Laboratoire d'Économie de la Firme et des Institutions, complementary currencies aim to protect, stimulate or orientate the economy. They may also be used to advance particular social, environmental, or political goals.
When speaking about complementary currencies, a number of overlapping and often interchangeable terms are in use: local or community currencies are complementary currencies used within a locality or other form of community (such as business-based or online communities); regional currencies are similar to local currencies, but are used within a larger geographical region; and sectoral currencies are complementary currencies used within a single economic sector, such as education or health care. Many private currencies are complementary currencies issued by private businesses or organizations. Other terms include alternative currency, auxiliary currency, and microcurrency. Mutual credit is a form of alternative currency, and thus any form of lending that does not go through the banking system can be considered a form of alternative currency. Barters are another type of alternative currency. These are actually exchange systems, which trade only items, without the use of any currency whatsoever. Finally, LETS is a special form of barter that trades points for items. One point stands for one worker-hour of work, and is thus a time-based currency.
Purposes
Current complementary currencies have often been designed intentionally to address specific issues, for example to increase financial stability. Most complementary currencies have multiple purposes and/or are intended to address multiple issues. They can be u
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https://en.wikipedia.org/wiki/Floor%20area%20ratio
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Floor area ratio (FAR) is the ratio of a building's total floor area (gross floor area) to the size of the piece of land upon which it is built. It is often used as one of the regulations in city planning along with the building-to-land ratio. The terms can also refer to limits imposed on such a ratio through zoning. FAR includes all floor areas but is indifferent to their spatial distribution on the lot whereas the building coverage ratio (or lot coverage) measures building footprint on the lot but is indifferent to building height.
Written as a formula, FAR = .
Lower maximum-allowed floor area ratios are linked to lower land values and lower housing density.
Terminology
Floor Area ratio is sometimes called floor space ratio (FSR), floor space index (FSI), site ratio or plot ratio.
The difference between FAR and FSI is that the first is a ratio, while the latter is an index.
Index numbers are values expressed as a percentage of a single base figure. Thus an FAR of 1.5 is translated as an FSI of 150%.
Regional variation
The terms most commonly used for this measurement vary from one country or region to the next.
In Australia floor space ratio (FSR) is used in New South Wales and plot ratio in Western Australia.
In France coefficient d'occupation des sols (COS) is used.
In India floor space index (FSI) and floor area ratio (FAR) are both used.
In the United Kingdom and Hong Kong both plot ratio and site ratio are used.
In Singapore the terms plot ratio and gross plot ratio (GPR) are more commonly used.
In the United States and Canada, floor space ratio (FSR) and floor area ratio (FAR) are both used.
Use ratios are used as a measure of the density of the site being developed. High FAR indicates a dense construction. The ratio is generated by dividing the building area by the parcel area, using the same units.
History
One of the purposes of the 1916 zoning ordinance of New York City was to prevent tall buildings from obstructing too much light and air.
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https://en.wikipedia.org/wiki/Water%20damage
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Water damage describes various possible losses caused by water intruding where it will enable attack of a material or system by destructive processes such as rotting of wood, mold growth, bacteria growth, rusting of steel, swelling of composite woods, de-laminating of materials such as plywood, short-circuiting of electrical devices, etc.
The damage may be imperceptibly slow and minor such as water spots that could eventually mar a surface, or it may be instantaneous and catastrophic such as burst pipes and flooding. However fast it occurs, water damage is a major contributor to loss of property.
An insurance policy may or may not cover the costs associated with water damage and the process of water damage restoration. While a common cause of residential water damage is often the failure of a sump pump, many homeowner's insurance policies do not cover the associated costs without an addendum which adds to the monthly premium of the policy. Often the verbiage of this addendum is similar to "Sewer and Drain Coverage".
In the United States, those individuals who are affected by wide-scale flooding may have the ability to apply for government and FEMA grants through the Individual Assistance program. On a larger level, businesses, cities, and communities can apply to the FEMA Public Assistance program for funds to assist after a large flood. For example, the city of Fond du Lac Wisconsin received $1.2 million FEMA grant after flooding in June 2008. The program allows the city to purchase the water damaged properties, demolish the structures, and turn the former land into public green space.
Causes
Water damage can originate by different sources such as a broken dishwasher hose, a washing machine overflow, a dishwasher leakage, broken/leaking pipes, flood waters, groundwater seepage, building envelope failures (leaking roof, windows, doors, siding, etc.) and clogged toilets. According to the Environmental Protection Agency, 13.7% of all water used in the home today
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https://en.wikipedia.org/wiki/Hydraulic%20conductivity
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In science and engineering, hydraulic conductivity (, in SI units of meters per second), is a property of porous materials, soils and rocks,< that describes the ease with which a fluid (usually water) can move through the pore space, or fractures network. It depends on the intrinsic permeability (, unit: m) of the material, the degree of saturation, and on the density and viscosity of the fluid. Saturated hydraulic conductivity, , describes water movement through saturated media.
By definition, hydraulic conductivity is the ratio of volume flux to hydraulic gradient yielding a quantitative measure of a saturated soil's ability to transmit water when subjected to a hydraulic gradient.
Methods of determination
There are two broad categories of determining hydraulic conductivity:
Empirical approach by which the hydraulic conductivity is correlated to soil properties like pore size and particle size (grain size) distributions, and soil texture
Experimental approach by which the hydraulic conductivity is determined from hydraulic experiments using Darcy's law
The experimental approach is broadly classified into:
Laboratory tests using soil samples subjected to hydraulic experiments
Field tests (on site, in situ) that are differentiated into:
small scale field tests, using observations of the water level in cavities in the soil
large scale field tests, like pump tests in wells or by observing the functioning of existing horizontal drainage systems.
The small scale field tests are further subdivided into:
infiltration tests in cavities above the water table
slug tests in cavities below the water table
The methods of determination of hydraulic conductivity and other related issues are investigated by several researchers and include more empirical approaches.
Estimation by empirical approach
Estimation from grain size
Allen Hazen derived an empirical formula for approximating hydraulic conductivity from grain size analyses:
where
Hazen's empirical coefficient, whic
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https://en.wikipedia.org/wiki/Yamaha%20YMF7xx
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There have been various families of Yamaha audio controllers labelled as YMF7xx.
OPL3-SA families
YMF701 (OPL3-SA): Incorporates OPL3 and OPL3-L features, 16-bit stereo CODEC, MPU-401-compatible MIDI interface, game port, Plug and Play ISA interface, Windows Sound System (CS4231) and Sound Blaster Pro compatibility.
YMF711 (OPL3-SA2): Based on OPL3-SA, it adds Plug and Play ISA compatibility, 10-pin interface supports 16-bit port address decode (top 4 bits), EEPROM interface, Zoomed video port, CPU and DAC interface for OPL4-ML, modem interface, or IDE CD-ROM interface.
YMF715 (OPL3-SA3): Based on OPL3-SA2, the OPL3-SA3 family adds 3D audio support via DirectSound3D and QSound.
DS-XG family
The last model number for controller chips used on ISA bus cards is 719; chips used on PCI cards start at 720 and higher. Chips for PCI bus standalone adapters are marked YMF7x4, while on-board or embedded systems are marked YMF7x0. The DS-XG series features hardware-assisted XG MIDI synthesis with either 32- or 64-note polyphony, full-duplex playback and recording at any samplerate (internally upsampled to 48 kHz), external game controller and MIDI interface, and a legacy block for DOS application support.
The DS-XG family processors were used in many inexpensive (sub-$50) soundcards. Relative performance was good despite the typical low cost. The cards were usually equipped with good quality 18-bit Digital-to-Analogue Converters, providing similar low noise and harmonic distortion levels to those found in semi-professional hardware.
The XG synthesizer on the DS-XG series features not only basic XG System Level 1, but also some of the MU-50 additions, and can reproduce most musical data previously programmed for the popular DB50XG daughterboard. YMF7x4 cards shipped with a 2 MB bank of 8-bit samples by default, which must be loaded into system RAM during booting. Neither the resolution nor content of the sample bank are hardware limitations. A user can load their own banks
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https://en.wikipedia.org/wiki/Electronic%20Signatures%20in%20Global%20and%20National%20Commerce%20Act
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The Electronic Signatures in Global and National Commerce Act (ESIGN, , ) is a United States federal law passed by the U.S. Congress to facilitate the use of electronic records and electronic signatures in interstate and foreign commerce by ensuring the validity and legal effect of contracts entered into electronically.
Although every state has at least one law pertaining to electronic signatures, it is the federal law that lays out the guidelines for interstate commerce. The general intent of the ESIGN Act is spelled out in the first section (101.a), that a contract or signature “may not be denied legal effect, validity, or enforceability solely because it is in electronic form”. This simple statement provides that electronic signatures and records are just as good as their paper equivalents, and therefore subject to the same legal scrutiny of authenticity that applies to paper documents.
Sections from the ESIGN Act
Definitions
Sec 106 of the ESIGN Act defines:
General intent
Consumer disclosure
Section 101 of the ESIGN Act, sub-section (b), preserves the rights of individuals to NOT USE electronic signatures. Here the law provides that individuals reserve the right to use a paper signature. Sub-section (c) is in direct support of (b) by requiring a "Consumer Disclosure" that the signatory has consented to use an electronic format.
Section 101(c)(1)(C) states that the consumer also "consent electronically, in a manner that reasonably demonstrates that the consumer can access information in the electronic form that will be used to provide the information that is the subject of the consent".
The consumer must provide affirmative consent, meaning that it cannot be assumed that a consumer has given consent simply because he/she has not chosen the option to deny consent, or has not responded to an option to grant consent.
The first public implementation of Section 106 of the ESIGN Act came nine months prior to its approval, when in October 1999, Save Daily found
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https://en.wikipedia.org/wiki/Tautological%20one-form
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In mathematics, the tautological one-form is a special 1-form defined on the cotangent bundle of a manifold In physics, it is used to create a correspondence between the velocity of a point in a mechanical system and its momentum, thus providing a bridge between Lagrangian mechanics and Hamiltonian mechanics (on the manifold ).
The exterior derivative of this form defines a symplectic form giving the structure of a symplectic manifold. The tautological one-form plays an important role in relating the formalism of Hamiltonian mechanics and Lagrangian mechanics. The tautological one-form is sometimes also called the Liouville one-form, the Poincaré one-form, the canonical one-form, or the symplectic potential. A similar object is the canonical vector field on the tangent bundle.
To define the tautological one-form, select a coordinate chart on and a canonical coordinate system on Pick an arbitrary point By definition of cotangent bundle, where and The tautological one-form is given by
with and being the coordinate representation of
Any coordinates on that preserve this definition, up to a total differential (exact form), may be called canonical coordinates; transformations between different canonical coordinate systems are known as canonical transformations.
The canonical symplectic form, also known as the Poincaré two-form, is given by
The extension of this concept to general fibre bundles is known as the solder form. By convention, one uses the phrase "canonical form" whenever the form has a unique, canonical definition, and one uses the term "solder form", whenever an arbitrary choice has to be made. In algebraic geometry and complex geometry the term "canonical" is discouraged, due to confusion with the canonical class, and the term "tautological" is preferred, as in tautological bundle.
Coordinate-free definition
The tautological 1-form can also be defined rather abstractly as a form on phase space. Let be a manifold and be the cotangen
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https://en.wikipedia.org/wiki/Z/Architecture
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z/Architecture, initially and briefly called ESA Modal Extensions (ESAME), is IBM's 64-bit complex instruction set computer (CISC) instruction set architecture, implemented by its mainframe computers. IBM introduced its first z/Architecture-based system, the z900, in late 2000. Later z/Architecture systems include the IBM z800, z990, z890, System z9, System z10, zEnterprise 196, zEnterprise 114, zEC12, zBC12, z13, z14, z15 and z16.
z/Architecture retains backward compatibility with previous 32-bit-data/31-bit-addressing architecture ESA/390 and its predecessors all the way back to the 32-bit-data/24-bit-addressing System/360. The IBM z13 is the last z Systems server to support running an operating system in ESA/390 architecture mode. However, all 24-bit and 31-bit problem-state application programs originally written to run on the ESA/390 architecture will be unaffected by this change.
Operating system support
IBM's operating systems z/OS, z/VSE, z/TPF, and z/VM are versions of MVS, VSE, Transaction Processing Facility (TPF), and VM that support z/Architecture. Older versions of z/OS, z/VSE, and z/VM continued to support 32-bit systems; z/OS version 1.6 and later, z/VSE Version 4 and later, and z/VM Version 5 and later require z/Architecture.
Linux also supports z/Architecture with Linux on IBM Z.
z/Architecture supports running multiple concurrent operating systems and applications even if they use different address sizes. This allows software developers to choose the address size that is most advantageous for their applications and data structures.
On July 7, 2009, IBM on occasion of announcing a new version of one of its operating systems implicitly stated that Architecture Level Set 4 (ALS 4) exists, and is implemented on the System z10 and subsequent machines. The ALS 4 is also specified in LOADxx as ARCHLVL 3, whereas the earlier z900, z800, z990, z890, System z9 specified ARCHLVL 2. Earlier announcements of System z10 simply specified that it implements
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https://en.wikipedia.org/wiki/WXSP-CD
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WXSP-CD (channel 15) is a low-power, Class A television station licensed to Grand Rapids, Michigan, United States, serving West Michigan as an affiliate of MyNetworkTV. It is owned by Nexstar Media Group alongside Grand Rapids–licensed NBC affiliate WOOD-TV (channel 8) and Battle Creek–licensed ABC affiliate WOTV (channel 41). The stations share studios on College Avenue Southeast in the Heritage Hill section of Grand Rapids, while WXSP-CD's transmitter is located in Walker (along I-96). Another repeater station licensed to Grand Rapids, WOLP-CD (channel 35), utilizes and is co-located with WOOD-TV's transmitter southwest of Middleville.
History
The station signed on the air on July 23, 1986, as W29AD, broadcasting on UHF channel 29. It moved to UHF channel 15 and acquired the W15AM calls on January 12, 1988. In the station's early days, it was a translator for World Harvest Television from WHME-TV in South Bend, Indiana, which is owned by LeSEA Broadcasting (now Family Broadcasting Corporation). The station was then purchased by LIN TV, the owner of WOOD-TV, and converted to the station's Local Weather Station (LWS) format with the call sign WOWD-LP (variation on WOOD-TV). WOWD and its low-power network of repeaters aired 24-hour weather information direct from WOOD-TV's weather center, including current conditions and severe weather coverage. This was in an early pre-digital format comparable to the now defunct NBC Weather Plus.
The weather programming aired from the mid-1990s until it switched to a general entertainment programming format a few years later. It featured graphic displays of various current conditions and forecasts as well as periodic forecast segments from WOOD-TV's meteorologists. Short commercial breaks would feature promotional advertising for WOOD-TV's news and entertainment programming, as well as LWS' station identification. A format change took place when it became a UPN affiliate on August 31, 1999 (displacing that network from secondary
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https://en.wikipedia.org/wiki/Symlink%20race
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A symlink race is a kind of software security vulnerability that results from a program creating files in an insecure manner. A malicious user can create a symbolic link to a file not otherwise accessible to them. When the privileged program creates a file of the same name as the symbolic link, it actually creates the linked-to file instead, possibly inserting content desired by the malicious user (see example below), or even provided by the malicious user (as input to the program).
It is called a "race" because in its typical manifestation, the program checks to see if a file by that name already exists; if it does not exist, the program then creates the file. An attacker must create the link in the interval between the check and when the file is created.
A symlink race can happen with antivirus products that decide they will quarantine or delete a suspicious file, and then go ahead and do that. During the interval between decision and action, malicious software can replace the suspicious file with a system or antivirus file that the malicious software wants overwritten.
Example
In this naive example, the Unix program foo is setuid. Its function is to retrieve information for the accounts specified by the user. For "efficiency", it sorts the requested accounts into a temporary file (/tmp/foo naturally) before making the queries.
The directory /tmp is world-writable. Malicious user Mallory creates a symbolic link to the file /root/.rhosts named /tmp/foo. Then, Mallory invokes foo with user as the requested account. The program creates the (temporary) file /tmp/foo (really creating /root/.rhosts) and puts information about the requested account (e.g. user password) in it. It removes the temporary file (merely removing the symbolic link).
Now the /root/.rhosts contains password information, which (if it even happens to be in the proper format) is the incantation necessary to allow anyone to use rlogin to log into the computer as the superuser.
Also in some Unix-
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https://en.wikipedia.org/wiki/Musikalisches%20W%C3%BCrfelspiel
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A (German for "musical dice game") was a system for using dice to randomly generate music from precomposed options. These games were quite popular throughout Western Europe in the 18th century. Several different games were devised, some that did not require dice, but merely choosing a random number.
The earliest example is Johann Kirnberger's (German for "The Ever-Ready Minuet and Polonaise Composer") (1757 [1st edition; revised 2nd 1783]). Examples by well known composers include C. P. E. Bach's (German for "A method for making six bars of double counterpoint at the octave without knowing the rules") (1758) and Maximilian Stadler's (French for "A table for composing minuets and trios to infinity, by playing with two dice") (1780).
In the early 20th century the Kaleidacousticon System, using arbitrarily combinable playing cards, was unsuccessfully marketed in the Boston area as a parlour game.
Aesthetics
According to Lawrence Zbikowski, "In truth, chance played little part in the success of the music produced by such games. Instead, what was required of the compilers...[was] a little knowledge about how to put the game together and an understanding of the formal design of waltzes, etc."
According to Stephen Hedges, "The 'galant' middle class in Europe was playing with mathematics. In this atmosphere of investigation and cataloguing, a systematic device that would seem to make it possible for anyone to write music was practically guaranteed popularity.<ref>Hedges, Stephen A. (1978). "Dice Music in the Eighteenth Century", pp. 184–185, Music & Letters, vol. 59, pp. 180–187. Quoted in Berkowitz (2010), p. 65n60.</ref>
According to Leonard Meyer, "Eighteenth-century composers constructed musical dice games while nineteenth century composers did not. ... [W]hat constrained the choice of figures [in seventeenth- and eighteenth-century music] were the claims of taste, coherent expression and propriety, given the genre of work being composed, rather than the inner
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https://en.wikipedia.org/wiki/Polly%20and%20Molly
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Polly and Molly (born 1997), two ewes, were the first mammals to have been successfully cloned from an adult somatic cell and to be transgenic animals at the same time. This is not to be confused with Dolly the Sheep, the first animal to be successfully cloned from an adult somatic cell where there wasn’t modification carried out on the adult donor nucleus. Polly and Molly, like Dolly the Sheep, were cloned at the Roslin Institute in Edinburgh, Scotland.
The creation of Polly and Molly built on the somatic nuclear transfer experiments that led to the cloning of Dolly the Sheep. The crucial difference was that in creating Polly and Molly, scientists used cells into which a new gene had been inserted. The gene chosen was a therapeutic protein to demonstrate the potential of such recombinant DNA technology combined with animal cloning. This could hopefully be used to produce pharmacological and therapeutic proteins to treat human diseases. The protein in question was the human blood clotting factor IX. Another difference from Dolly the Sheep was the source cell type of the nucleus that was transferred. Although Polly and Molly were nuclear clones, they had different mtDNA that was different from the nuclear cells where they received their DNA.
Prior to the production of Polly and Molly, the only demonstrated way to make a transgenic animal was by microinjection of DNA into the pronuclei of fertilized oocytes (eggs). However, only a small proportion of the animals will integrate the injected DNA into their genome. In the rare cases that they do integrate this new genetic information, the pattern of expression of the injected transgene's protein due to the random integration is very variable. As the aim of such research is to produce an animal that expresses a particular protein in high levels in, for example, its milk, microinjection is a very costly procedure that does not usually produce the desired animal.
In mice, there is an additional option for genetic transfe
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https://en.wikipedia.org/wiki/Real-time%20clock%20alarm
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A real time clock alarm is a feature that can be used to allow a computer to 'wake up' after shut down to execute tasks every day or on a certain day. It can sometimes be found in the 'Power Management' section of a motherboard's BIOS/UEFI setup. Wake On LAN, Wake on ring, and IPMI functions could also be used to start a computer after it is turned off.
In Linux, the real time clock alarm can be set or retrieved using /proc/acpi/alarm or /sys/class/rtc/rtc0/wakealarm. Alternatively the rtcwake utility may be used which prevents problems when using local time instead of UTC by automatically processing the /etc/adjtime file. systemd can be used to wake a system and run a task at a specific time.
In Microsoft Windows there are different programs which could be used to 'wake up' a computer from standby or hibernation. Task Scheduler settings for power management can be used to 'Wake the computer to run this task'.
References
See also
Alert on LAN
Wake-on-Ring (WOR)
Wired for Management
Wake-on-LAN
Alarms
Alarm
Operating system technology
BIOS
Unified Extensible Firmware Interface
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https://en.wikipedia.org/wiki/Sentences%20of%20Sextus
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The Sentences of Sextus, also called the Sayings of Sextus, is a Hellenistic Pythagorean collection of maxims which was popular among Christians and translated into several languages. The identity of the Sextus who originated the collection is unknown.
Transmission
The Sentences was probably compiled in the second century AD. The original collection was pagan. It was later modified to reflect a Christian viewpoint, although there are no explicit references to Jesus.
The earliest mention of the Sentences is by Origen in the mid third century. Origen quotes Sextus on self-castration, a widespread habit among ascetic early Christians, which Origen deplores, and mentions in passing that the work is one "that many considered to be tested by time."
A Latin translation was made from the original Greek by Rufinus of Aquileia under the title Anulus around 400. A partial Coptic translation was discovered in one of the books of the New Testament apocrypha recovered from the Nag Hammadi library in 1945. A Syriac translation is also known, its title translates Dicta Selecta Sancti Xysti Episcopi Romani ('select sayings of Saint Xystus, Roman bishop').
Authorship
The identity of Sextus has been disputed for a long time. The identification with Pope Xystus II (), current by the time of the Latin and Syriac translations, is denied by Jerome, who calls the author Sextus Pythagoreus. Such attributions to important figures, which happened frequently, were usually attempts to give the works more authority.
One possible author of the Sentences is Quintus Sextius, a Roman philosopher who combined Stoicism with Pythagoreanism, and who lived in the 1st century BC.
Contents
The work is similar to the sayings gospels called the Gospel of Phillip and the Gospel of Thomas in that it is purely a collection of sayings, with no bridging framework. Unlike the Christian sayings gospels, the wisdom comes from a man named Sextus rather than Jesus. Sextus appears to have been a Pythagorean. Ther
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https://en.wikipedia.org/wiki/Advanced%20Microcontroller%20Bus%20Architecture
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The Arm Advanced Microcontroller Bus Architecture (AMBA) is an open-standard, on-chip interconnect specification for the connection and management of functional blocks in system-on-a-chip (SoC) designs. It facilitates development of multi-processor designs with large numbers of controllers and components with a bus architecture. Since its inception, the scope of AMBA has, despite its name, gone far beyond microcontroller devices. Today, AMBA is widely used on a range of ASIC and SoC parts including applications processors used in modern portable mobile devices like smartphones. AMBA is a registered trademark of Arm Ltd.
AMBA was introduced by Arm in 1996. The first AMBA buses were the Advanced System Bus (ASB) and the Advanced Peripheral Bus (APB). In its second version, AMBA 2 in 1999, Arm added AMBA High-performance Bus (AHB) that is a single clock-edge protocol. In 2003, Arm introduced the third generation, AMBA 3, including Advanced eXtensible Interface (AXI) to reach even higher performance interconnect and the Advanced Trace Bus (ATB) as part of the CoreSight on-chip debug and trace solution. In 2010 the AMBA 4 specifications were introduced starting with AMBA 4 AXI4, then in 2011 extending system-wide coherency with AMBA 4 AXI Coherency Extensions (ACE). In 2013 the AMBA 5 Coherent Hub Interface (CHI) specification was introduced, with a re-designed high-speed transport layer and features designed to reduce congestion. These protocols are today the de facto standard for embedded processor bus architectures because they are well documented and can be used without royalties.
Design principles
An important aspect of an SoC is not only which components or blocks it houses, but also how they interconnect. AMBA is a solution for the blocks to interface with each other.
The objective of the AMBA specification is to:
facilitate right-first-time development of embedded microcontroller products with one or more CPUs, GPUs or signal processors,
be technology inde
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https://en.wikipedia.org/wiki/ARexx
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ARexx is an implementation of the Rexx language for the Amiga, written in 1987 by William S. Hawes, with a number of Amiga-specific features beyond standard REXX facilities. Like most REXX implementations, ARexx is an interpreted language. Programs written for ARexx are called "scripts", or "macros"; several programs offer the ability to run ARexx scripts in their main interface as macros.
ARexx can easily communicate with third-party software that implements an "ARexx port". Any Amiga application or script can define a set of commands and functions for ARexx to address, thus making the capabilities of the software available to the scripts written in ARexx.
ARexx can direct commands and functions to several applications from the same script, thus offering the opportunity to mix and match functions from the different programs. For example, an ARexx script could extract data from a database, insert the data into a spreadsheet to perform calculations on it, then insert tables and charts based on the results into a word processor document.
History
ARexx was first created in 1987, developed for the Amiga by William S. Hawes. It is based on the REXX language described by Mike Cowlishaw in the book The REXX Language: A Practical Approach to Programming. ARexx was included by Commodore with AmigaOS 2.0 in 1990, and has been included with all subsequent AmigaOS releases. This later version of ARexx follows the official REXX language closely; Hawes was later involved in drafting the ANSI standard for REXX.
ARexx is written in 68000 Assembly, and cannot therefore function at full speed with new PPC CPUs, a version of ARexx has not been rewritten for them and is still missing from MorphOS 3.0. William Hawes is no longer involved in development of Amiga programs and no other Amiga-related firm is financing new versions of ARexx. Notwithstanding this fact, the existing version of ARexx continues to be used, although it is not distributed with MorphOS.
From the ARexx manual
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https://en.wikipedia.org/wiki/Vascular%20endothelial%20growth%20factor
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Vascular endothelial growth factor (VEGF, ), originally known as vascular permeability factor (VPF), is a signal protein produced by many cells that stimulates the formation of blood vessels. To be specific, VEGF is a sub-family of growth factors, the platelet-derived growth factor family of cystine-knot growth factors. They are important signaling proteins involved in both vasculogenesis (the de novo formation of the embryonic circulatory system) and angiogenesis (the growth of blood vessels from pre-existing vasculature).
It is part of the system that restores the oxygen supply to tissues when blood circulation is inadequate such as in hypoxic conditions. Serum concentration of VEGF is high in bronchial asthma and diabetes mellitus.
VEGF's normal function is to create new blood vessels during embryonic development, new blood vessels after injury, muscle following exercise, and new vessels (collateral circulation) to bypass blocked vessels.
It can contribute to disease. Solid cancers cannot grow beyond a limited size without an adequate blood supply; cancers that can express VEGF are able to grow and metastasize. Overexpression of VEGF can cause vascular disease in the retina of the eye and other parts of the body. Drugs such as aflibercept, bevacizumab, ranibizumab, and pegaptanib can inhibit VEGF and control or slow those diseases.
History
In 1970, Judah Folkman et al. described a factor secreted by tumors causing angiogenesis and called it tumor angiogenesis factor. In 1983 Senger et al. identified a vascular permeability factor secreted by tumors in guinea pigs and hamsters. In 1989 Ferrara and Henzel described an identical factor in bovine pituitary follicular cells which they purified, cloned and named VEGF. A similar VEGF alternative splicing was discovered by Tischer et al. in 1991. Between 1996 and 1997, Christinger and De Vos obtained the crystal structure of VEGF, first at 2.5 Å resolution and later at 1.9 Å.
Fms-like tyrosine kinase-1 (flt-1) was sh
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https://en.wikipedia.org/wiki/Falsework
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Falsework consists of temporary structures used in construction to support a permanent structure until its construction is sufficiently advanced to support itself. For arches, this is specifically called centering. Falsework includes temporary support structures for formwork used to mold concrete in the construction of buildings, bridges, and elevated roadways.
The British Standards of practice for falsework, BS 5975:2008, defines falsework as "Any temporary structure used to support a permanent structure while it is not self-supporting."
History
Falsework has been employed in bridge and viaduct construction since ancient times. The Romans were renowned for its use, as at the Limyra Bridge in Turkey. Until the turn of the 20th century almost all falsework was constructed from timber. To compensate for timber shortages in different regions and to rationalize labor and material usage, new systems were developed.
The major developments include the design of connection devices (coupler), transitions to other spanning beams such as steel pipes or profiles or reusable timber beams, and adjustable steel props. In 1935 W.A. de Vigier designed an adjustable steel prop which revolutionized many aspects of the construction industry including to support slab formwork, wall formwork, trench sheeting and falsework. Materials from which falsework systems are manufactured have also diversified from traditional steel and timber to aluminium components.
In the UK, BS 5975 gives recommendations for the design and use of falsework on construction sites. It was first introduced by the British Standards Institute in March 1982 and the third version was published in 2008 with Amendment 1 in 2011. The new revisions bring the code up to date with methodology developed in the new CDM 2007 regulations and also the requirements of the new European codes EN 12811-1:2003 Temporary works equipment - Part 1: scaffolds, and EN 12812:2004, falsework - performance requirements and general desi
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https://en.wikipedia.org/wiki/The%20Tao%20of%20Programming
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The Tao of Programming is a book written in 1987 by Geoffrey James. Written in a tongue-in-cheek style spoof of classic Taoist texts such as the Tao Te Ching and Zhuangzi which belies its serious message, it consists of a series of short anecdotes divided into nine "books":
The Silent Void
The Ancient Masters
Design
Coding
Maintenance
Management
Corporate Wisdom
Hardware and Software
Epilogue
Geoffrey James wrote two other books on this theme, The Zen of Programming (978-0931137099) in 1988 and Computer Parables: Enlightenment in the Information Age (978-0931137136) in 1989.
See also
Hacker koan
References
External links
The Tao of Programming
Software development books
1987 non-fiction books
Computer humor
Satirical books
Taoism in popular culture
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https://en.wikipedia.org/wiki/Bioindicator
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A bioindicator is any species (an indicator species) or group of species whose function, population, or status can reveal the qualitative status of the environment. The most common indicator species are animals. For example, copepods and other small water crustaceans that are present in many water bodies can be monitored for changes (biochemical, physiological, or behavioural) that may indicate a problem within their ecosystem. Bioindicators can tell us about the cumulative effects of different pollutants in the ecosystem and about how long a problem may have been present, which physical and chemical testing cannot.
A biological monitor or biomonitor is an organism that provides quantitative information on the quality of the environment around it. Therefore, a good biomonitor will indicate the presence of the pollutant and can also be used in an attempt to provide additional information about the amount and intensity of the exposure.
A biological indicator is also the name given to a process for assessing the sterility of an environment through the use of resistant microorganism strains (e.g. Bacillus or Geobacillus). Biological indicators can be described as the introduction of a highly resistant microorganisms to a given environment before sterilization, tests are conducted to measure the effectiveness of the sterilization processes. As biological indicators use highly resistant microorganisms, any sterilization process that renders them inactive will have also killed off more common, weaker pathogens.
Overview
A bioindicator is an organism or biological response that reveals the presence of pollutants by the occurrence of typical symptoms or measurable responses and is, therefore, more qualitative.
These organisms (or communities of organisms) can be used to deliver information on alterations in the environment or the quantity of environmental pollutants by changing in one of the following ways: physiologically, chemically or behaviourally.
The information ca
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https://en.wikipedia.org/wiki/Lock-in%20amplifier
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A lock-in amplifier is a type of amplifier that can extract a signal with a known carrier wave from an extremely noisy environment. Depending on the dynamic reserve of the instrument, signals up to a million times smaller than noise components, potentially fairly close by in frequency, can still be reliably detected. It is essentially a homodyne detector followed by low-pass filter that is often adjustable in cut-off frequency and filter order.
The device is often used to measure phase shift, even when the signals are large, have a high signal-to-noise ratio and do not need further improvement.
Recovering signals at low signal-to-noise ratios requires a strong, clean reference signal with the same frequency as the received signal. This is not the case in many experiments, so the instrument can recover signals buried in the noise only in a limited set of circumstances.
The lock-in amplifier is commonly believed to have been invented by Princeton University physicist Robert H. Dicke who founded the company Princeton Applied Research (PAR) to market the product. However, in an interview with Martin Harwit, Dicke claims that even though he is often credited with the invention of the device, he believes that he read about it in a review of scientific equipment written by Walter C. Michels, a professor at Bryn Mawr College. This could have been a 1941 article by Michels and Curtis, which in turn cites a 1934 article by C. R. Cosens, while another timeless article was written by C. A. Stutt in 1949.
Whereas traditional lock-in amplifiers use analog frequency mixers and RC filters for the demodulation, state-of-the-art instruments have both steps implemented by fast digital signal processing, for example, on an FPGA. Usually sine and cosine demodulation is performed simultaneously, which is sometimes also referred to as dual-phase demodulation. This allows the extraction of the in-phase and the quadrature component that can then be transferred into polar coordinates, i.
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https://en.wikipedia.org/wiki/Toxoid
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A toxoid is an inactivated toxin (usually an exotoxin) whose toxicity has been suppressed either by chemical (formalin) or heat treatment, while other properties, typically immunogenicity, are maintained. Toxins are secreted by bacteria, whereas toxoids are altered form of toxins; toxoids are not secreted by bacteria. Thus, when used during vaccination, an immune response is mounted and immunological memory is formed against the molecular markers of the toxoid without resulting in toxin-induced illness. Such a preparation is also known as an anatoxin. There are toxoids for prevention of diphtheria, tetanus and botulism.
Toxoids are used as vaccines because they induce an immune response to the original toxin or increase the response to another antigen since the toxoid markers and toxin markers are preserved. For example, the tetanus toxoid is derived from the tetanospasmin produced by Clostridium tetani. The latter causes tetanus and is vaccinated against by the DTaP vaccine. While patients may sometimes complain of side effects after a vaccine, these are associated with the process of mounting an immune response and clearing the toxoid, not the direct effects of the toxoid. The toxoid does not have virulence as the toxin did before inactivation.
Toxoids are also useful in the production of human antitoxins. Multiple doses of tetanus toxoid are used by many plasma centers in the United States for the development of highly immune persons for the production of human anti-tetanus immune globulin (tetanus immune globulin (TIG), HyperTet (c)), which has replaced horse serum-type tetanus antitoxin in most of the developed world.
Toxoids are also used in the production of conjugate vaccines. The highly antigenic toxoids help draw attention to weaker antigens such as polysaccharides found in the bacterial capsule.
List of toxoids
References
Immunology
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https://en.wikipedia.org/wiki/TMPGEnc
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TMPGEnc or TSUNAMI MPEG Encoder is a video transcoder software application primarily for encoding video files to VCD and SVCD-compliant MPEG video formats and was developed by Hiroyuki Hori and Pegasys Inc. TMPGEnc can also refer to the family of software video encoders created after the success of the original TMPGEnc encoder. These include: TMPGEnc Plus, TMPGEnc Free Version, TMPGenc Video Mastering Works, TMPGEnc Authoring Works, TMPGEnc MovieStyle and TMPGEnc MPEG Editor. TMPGEnc products run on Microsoft Windows.
The free trial version of TMPGEnc Video Mastering works has a 14-day time limit. The TMPGEnc Free Version has 30-day time limit for MPEG-2 encoding, MPEG-1 encoding is without limit, but it can be used only for non-commercial, personal or demonstration purposes.
History
The first beta versions of the TMPGEnc encoder were freely available in 2000 and 2001 and were known as Tsunami MPEG Encoder. The first "stable" version was TMPGEnc 2.00, released on 2001-11-01. In December 2001, sales of "TMPGEnc Plus" started in Japan. In January 2002, the "TMPGEnc Plus - English version" was released. In August 2002, TMPGEnc DVD Source Creator was released and bundled with Sony "Vaio" PC in Japan. In April 2003, "TMPGEnc DVD Author - English version" was released. In March 2005, Tsunami MPEG Video Encoder XPress was released. In August 2005, "TSUNAMI" and "TMPGEnc" were combined into one brand.
TMPGEnc Plus/TMPGEnc Free Version was often rated as one of the best-quality MPEG-1/MPEG-2 encoders, alongside Canopus ProCoder and Cinema Craft Encoder. The popularity of TMPGEnc encoders has spawned various other products and "TMPGEnc" is now used as a general brand name for products such TMPGEnc Authoring Works (a consumer-grade Blu-ray Disc, DVD, and DivX authoring tool), TMPGEnc MovieStyle (a video converter primarily for portable and set-top devices), and TMPGEnc MPEG Editor (an MPEG editing program). TMPGEnc Plus is currently still sold by Pegasys Inc., alongside T
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https://en.wikipedia.org/wiki/Clifton%20Fadiman
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Clifton Paul "Kip" Fadiman (May 15, 1904 – June 20, 1999) was an American intellectual, author, editor, and radio and television personality. He began his work in radio, and switched to television later in his career.
Background
Born in Brooklyn, New York, Fadiman was a nephew of the emigree Ukrainian psychologist Boris Sidis and a first cousin of the child prodigy William James Sidis.
Fadiman grew up in Brooklyn. His mother worked as a nurse; his father, Isadore, immigrated from Russian empire in 1892 and worked as a druggist.
He attended Columbia College at Columbia University. One of his teachers was lifelong friend Mark Van Doren; his undergraduate contemporaries included Jacques Barzun, Mortimer Adler, Lionel Trilling, Herbert Solow, Arthur F. Burns, Frank S. Hogan, Louis Zukofsky and Whittaker Chambers. Though he entered with the Class of 1924, his graduation was delayed until 1925 because of financial constraints. Chambers clearly includes Fadiman in a group of ernste Menschen ["serious people"], whose ability to attend Columbia he attributes to "a struggle with a warping poverty impossible for those who have not glimpsed it to imagine it." He graduated Phi Beta Kappa.
Fadiman had ambitions to become a scholar, but at graduation, the chairman of the English Department told him, "We have room for only one Jew, and we have chosen Mr. Trilling."
Career
After graduation from Columbia, Fadiman taught English at the Ethical Culture High School (now known as the "Fieldston School") in the Bronx from 1925 to 1927.
Literature
Fadiman worked ten years for Simon & Schuster, ending as its chief editor. At his interview with Max Schuster (a fellow alumnus of Columbia), Fadiman pulled out a folder with a hundred ideas for books. Among Fadiman's original one hundred was to turn Robert Ripley's newspaper cartoon, Believe it or Not! into book form. The series has gone on to sell over 30 million copies.
While at Simon & Schuster, he started the translation career of W
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https://en.wikipedia.org/wiki/Wire%20drawing
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Wire drawing is a metalworking process used to reduce the cross-section of a wire by pulling the wire through a single, or series of, drawing die(s). There are many applications for wire drawing, including electrical wiring, cables, tension-loaded structural components, springs, paper clips, spokes for wheels, and stringed musical instruments. Although similar in process, drawing is different from extrusion, because in drawing the wire is pulled, rather than pushed, through the die. Drawing is usually performed at room temperature, thus classified as a cold working process, but it may be performed at elevated temperatures for large wires to reduce forces.
Of the elemental metals, copper, silver, gold, and platinum are the most ductile and immune from many of the problems associated with cold working.
Process
The wire drawing process is quite simple in concept. The wire is prepared by shrinking the beginning of it, by hammering, filing, rolling or swaging, so that it will fit through the die; the wire is then pulled through the die. As the wire is pulled through the die, its volume remains the same, so as the diameter decreases, the length increases. Usually the wire will require more than one draw, through successively smaller dies, to reach the desired size. The American wire gauge scale is based on this. This can be done on a small scale with a draw plate, or on a large commercial scale using automated machinery. The process of wire drawing changes material properties due to cold working.
The area reduction in small wires is generally 15–25% and in larger wires is 20–45%. The exact die sequence for a particular job is a function of area reduction, input wire size and output wire size. As the area reduction changes, so does the die sequence.
Very fine wires are usually drawn in bundles. In a bundle, the wires are separated by a metal with similar properties, but with lower chemical resistance so that it can be removed after drawing. If the reduction in are
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https://en.wikipedia.org/wiki/Solomon%20W.%20Golomb
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Solomon Wolf Golomb (; May 30, 1932 – May 1, 2016) was an American mathematician, engineer, and professor of electrical engineering at the University of Southern California, best known for his works on mathematical games. Most notably, he invented Cheskers (a hybrid between chess and checkers) in 1948. He also fully described polyominoes and pentominoes in 1953. He specialized in problems of combinatorial analysis, number theory, coding theory, and communications. Pentomino boardgames, based on his work, would go on to inspire Tetris.
Achievements
Golomb, a graduate of the Baltimore City College high school, received his bachelor's degree from Johns Hopkins University and master's and doctorate degree in mathematics from Harvard University in 1957 with a dissertation on "Problems in the Distribution of the Prime Numbers".
While working at the Glenn L. Martin Company he became interested in communications theory and began his work on shift register sequences. He spent his Fulbright year at the University of Oslo and then joined the Jet Propulsion Laboratory at Caltech, where he researched military and space communications. He joined the faculty of USC in 1963 and was awarded full tenure two years later.
Golomb pioneered the identification of the characteristics and merits of maximum length shift register sequences, also known as pseudorandom or pseudonoise sequences, which have extensive military, industrial and consumer applications. Today, millions of cordless and cellular phones employ pseudorandom direct-sequence spread spectrum implemented with shift register sequences. His efforts made USC a center for communications research.
Golomb was the inventor of Golomb coding, a form of entropy encoding. Golomb rulers, used in astronomy and in data encryption, are also named for him, as is one of the main generation techniques of Costas arrays, the Lempel-Golomb generation method.
He was a regular columnist, writing Golomb's Puzzle Column in the IEEE Information
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https://en.wikipedia.org/wiki/Phytosterol
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Phytosterols are phytosteroids, similar to cholesterol, that serve as structural components of biological membranes of plants. They encompass plant sterols and stanols. More than 250 sterols and related compounds have been identified. Free phytosterols extracted from oils are insoluble in water, relatively insoluble in oil, and soluble in alcohols.
Phytosterol-enriched foods and dietary supplements have been marketed for decades. Despite well-documented LDL cholesterol-lowering effects from long-term consumption of phytosterols, there is insufficient evidence for an effect on cardiovascular diseases, fasting blood sugar, glycated hemoglobin, or overall mortality rate.
Structure
They have a fused polycyclic structure and vary in carbon side chains and / or presence or absence of a double bond (saturation). They are divided into 4,4-dimethyl phytosterols, 4-monomethyl phytosterols, and 4-desmethyl phytosterols based on the location of methyl groups at the carbon-4 position. Stanols are saturated sterols, having no double bonds in the sterol ring structure.
The molecule in the article lead is β-sitosterol. The nomenclature is shown on the right.
By removing carbon 242, campesterol is obtained.
By removing carbons 241 and 242, cholesterol is obtained.
Removing a hydrogen from carbons 22 and 23 yields stigmasterol (stigmasta-5,22-dien-3β-ol).
By hydrogenating the double bond between carbons 5 and 6, β-sitostanol (Stigmastanol) is obtained.
By hydrogenating the double bond between carbons 5 and 6 and removing carbon 242, campestanol is obtained.
Removing carbon 242 and hydrogens from carbons 22 and 23, and inverting the stereochemistry at C-24 yields brassicasterol (ergosta-5,22-dien-3β-ol).
Further removal of hydrogens from carbons 7 and 8 from brassicasterol yields ergosterol (ergosta-5,7,22-trien-3β-ol). Important: Ergosterol is not a plant sterol. Ergosterol is a component of fungal cell membranes, serving the same function in fungi that cholesterol serves in ani
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https://en.wikipedia.org/wiki/Digital%20paper
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Digital paper, also known as interactive paper, is patterned paper used in conjunction with a digital pen to create handwritten digital documents. The printed dot pattern uniquely identifies the position coordinates on the paper. The digital pen uses this pattern to store handwriting and upload it to a computer.
The paper
The dot pattern is a two-dimensional barcode; the most common is the proprietary Anoto dot pattern. In the Anoto dot pattern, the paper is divided into a grid with a spacing of about 0.3 mm, a dot is printed near each intersection offset slightly in one of four directions, a camera in the pen typically records a 6 x 6 groups of dots. The full pattern is claimed to consist of 669,845,157,115,773,458,169 dots, and to encompass an area exceeding 4.6 million km² (this corresponds to 73 trillion unique sheets of letter-size paper).
The complete pattern space is divided into various domains. These domains can be used to define paper types, or to indicate the paper's purpose (for example, memo formatting, personal planners, notebook paper, Post-it notes, et cetera).
The Anoto dot pattern can be printed onto almost any paper, using a standard printing process of at least 600 dpi resolution (some claim a required resolution of 1,000 dpi),
and carbon-based black ink. The paper can be any shape or size greater than 2 mm to a side. The ink absorbs infrared light transmitted from the digital pen; the pen contains a receiver that interprets the pattern of light reflected from the paper. Other colors of ink, including non-carbon-based black, can be used to print information that will be visible to the user, and invisible to the pen.
Standard black and white laser printers or color laser printers with a resolution of 600 dpi can be used to print the Anoto dot pattern.
With a typical CMYK color laser printer, it's possible use full-color text and graphics that cover the entire page by avoiding using black (i.e., under color removal is turned off) and instead u
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https://en.wikipedia.org/wiki/Dynamic%20Data%20Exchange
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In computing, Dynamic Data Exchange (DDE) is a technology for interprocess communication used in early versions of Microsoft Windows and OS/2. DDE allows programs to manipulate objects provided by other programs, and respond to user actions affecting those objects. DDE was partially superseded by Object Linking and Embedding (OLE), and is currently maintained in Windows systems only for the sake of backward compatibility.
History and architecture
Dynamic Data Exchange was first introduced in 1987 with the release of Windows 2.0 as a method of interprocess communication so that one program could communicate with or control another program, somewhat like Sun's RPC (Remote Procedure Call). At the time, the only method for communication between the operating system and client applications was the "Windows Messaging Layer." DDE extended this protocol to allow peer-to-peer communication among client applications, via message broadcasts.
Because DDE runs via message broadcasts, it is vulnerable to any window-management code that does not pump messages. This problem was not considered during the design of DDE, because DDE predates pre-emptive multitasking.
Moreover, any code managing a window handle can respond to a DDE broadcast; the initiator of DDE must distinguish between expected and unexpected responses. DDE interlocutors usually express what information they seek in terms of hierarchical string keys. For example, a cell in Microsoft Excel was known to DDE by its "application" name. Each application could further organize information by groups known as "topic" and each topic could serve up individual pieces of data as an "item". For example, if a user wanted to pull a value from Microsoft Excel which was contained in a spreadsheet called "Book1.xls" in the cell in the first row and first column, the application would be "Excel", the topic "Book1.xls" and the item "r1c1". Internal changes in the cell due to Excel actions would then be signaled (in reverse
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https://en.wikipedia.org/wiki/BLIS/COBOL
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BLIS/COBOL is a discontinued operating system that was written in COBOL. It is the only such system to gain reasonably wide acceptance. It was optimised to compile business applications written in COBOL. BLIS was available on a range of Data General Nova and Data General Eclipse 16-bit minicomputers. It was marketed by Information Processing, Inc. (IPI), who regularly exhibited the product at the National Computer Conference in the 1970s and 80s. It was priced between US$830 and $10,000 depending on the number of supported users and features. In 1977, IPI boasted over 100 operational installations of the system worldwide.
By 1985, a version for the IBM PC existed called PC-BLIS.
Originally, most operating systems were written in assembly language for a particular processor or family of processors. Non-assembler operating systems were comparatively slow, but were easier for revision and repair. One of the reasons for the C programming language's low-level features, which resemble assembly language in some ways, is an early intent to use it for writing operating systems. Similar goals led to IBM's development of PL/S. The high-level nature of COBOL, which created some problems for operating system development, was partially addressed in BLIS, since it was deliberately optimized for COBOL.
References
Discontinued operating systems
COBOL
Assembly language software
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https://en.wikipedia.org/wiki/Open%20Grid%20Services%20Infrastructure
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The Open Grid Services Infrastructure (OGSI) was published by the Global Grid Forum (GGF) as a proposed recommendation in June 2003. It was intended to provide an infrastructure layer for the Open Grid Services Architecture (OGSA). OGSI takes the statelessness issues (along with others) into account by essentially extending Web services to accommodate grid computing resources that are both transient and stateful.
Obsolescence
Web services groups started to integrate their own approaches to capturing state into the Web Services Resource Framework (WSRF). With the release of GT4, the open source tool kit is migrating back to a pure Web services implementation (rather than OGSI), via integration of the WSRF.
"OGSI, which was the former set of extensions to Web services to provide stateful interactions -- I would say at this point is obsolete," Jay Unger said. "That was the model that was used in the Globus Toolkit 3.0, but it's been replaced by WSRF, WS-Security, and the broader set of Web services standards. But OGSA, which focuses on specific service definition in the areas of execution components, execution modeling, grid data components, and information virtualization, still has an important role to play in the evolution of standards and open source tool kits like Globus."
Implementations
Globus Toolkit version 3 contains an implementation of OGSI.
References
Grid computing
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https://en.wikipedia.org/wiki/MonetDB
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MonetDB is an open-source column-oriented relational database management system (RDBMS) originally developed at the Centrum Wiskunde & Informatica (CWI) in the Netherlands.
It is designed to provide high performance on complex queries against large databases, such as combining tables with hundreds of columns and millions of rows.
MonetDB has been applied in high-performance applications for online analytical processing, data mining, geographic information system (GIS), Resource Description Framework (RDF), text retrieval and sequence alignment processing.
History
Data mining projects in the 1990s required improved analytical database support. This resulted in a CWI spin-off called Data Distilleries, which used early MonetDB implementations in its analytical suite. Data Distilleries eventually became a subsidiary of SPSS in 2003, which in turn was acquired by IBM in 2009.
MonetDB in its current form was first created in 2002 by doctoral student Peter Boncz and professor Martin L. Kersten as part of the 1990s' MAGNUM research project at University of Amsterdam. It was initially called simply Monet, after the French impressionist painter Claude Monet. The first version under an open-source software license (a modified version of the Mozilla Public License) was released on September 30, 2004. When MonetDB version 4 was released into the open-source domain, many extensions to the code base were added by the MonetDB/CWI team, including a new SQL front end, supporting the SQL:2003 standard.
MonetDB introduced innovations in all layers of the DBMS: a storage model based on vertical fragmentation, a modern CPU-tuned query execution architecture that often gave MonetDB a speed advantage over the same algorithm over a typical interpreter-based RDBMS. It was one of the first database systems to tune query optimization for CPU caches. MonetDB includes automatic and self-tuning indexes, run-time query optimization, and a modular software architecture.
By 2008, a follow-on p
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https://en.wikipedia.org/wiki/Data%20mapping
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In computing and data management, data mapping is the process of creating data element mappings between two distinct data models. Data mapping is used as a first step for a wide variety of data integration tasks, including:
Data transformation or data mediation between a data source and a destination
Identification of data relationships as part of data lineage analysis
Discovery of hidden sensitive data such as the last four digits of a social security number hidden in another user id as part of a data masking or de-identification project
Consolidation of multiple databases into a single database and identifying redundant columns of data for consolidation or elimination
For example, a company that would like to transmit and receive purchases and invoices with other companies might use data mapping to create data maps from a company's data to standardized ANSI ASC X12 messages for items such as purchase orders and invoices.
Standards
X12 standards are generic Electronic Data Interchange (EDI) standards designed to allow a company to exchange data with any other company, regardless of industry. The standards are maintained by the Accredited Standards Committee X12 (ASC X12), with the American National Standards Institute (ANSI) accredited to set standards for EDI. The X12 standards are often called ANSI ASC X12 standards.
The W3C introduced R2RML as a standard for mapping data in a relational database to data expressed in terms of the Resource Description Framework (RDF).
In the future, tools based on semantic web languages such as RDF, the Web Ontology Language (OWL) and standardized metadata registry will make data mapping a more automatic process. This process will be accelerated if each application performed metadata publishing. Full automated data mapping is a very difficult problem (see semantic translation).
Hand-coded, graphical manual
Data mappings can be done in a variety of ways using procedural code, creating XSLT transforms or by using graphi
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https://en.wikipedia.org/wiki/GAFOR
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GAFOR ("General Aviation Forecast") is a format for reporting weather information for aviation purposes. The GAFOR is used in many European countries. In order to easy transmit and understand GAFOR forecasts, the original (local) names are systematically replaced by a code number. There are two kinds of application:
In France and Germany for example the GAFOR - Code refers to regions.
In Switzerland, Austria, Croatia and Slovenia the code refers to often used or simply usable and therefore predefined routes for crossing the country. This is a special need for the alpine or other mountainous regions, where VFR routing between mountains higher than the physical performance of pilots (oxygen) or the aircraft are common.
GAFOR codes
The GAFOR gives information on weather conditions (VIS/ceiling) prevailing along the main VFR Routes in Switzerland, Austria, Croatia and Slovenia. VIS and ceiling conditions considered, four weather categories are distinguished:
X: closed
M: marginal
D: difficult
O: open
Other weather phenomena dangerous for aviation, such as icing and turbulence are forecasted in GAMET or flight forecast. For this reason they are not taken into account in GAFOR.
Transmission of Swiss GAFOR
The GAFOR is spoken on magnetic disk or tape at Zurich and Genève. The forecast enumerates weather categories in chronological order, first for groups of routes REF: 4.4.2 then for single routes REF: 4.4.3, using the ICAO spelling alphabet:
O = OSCAR
D = DELTA
M = MIKE
X = X-RAY
GAFOR Routes (groups) in Switzerland
Each group is or can be divided into several distinct routes, e.g. for choosing one of different possible passes through the Alps.
Groups of routes:
00 Basel-Schaffhausen-Altenrhein
10 Genève-Grenchen-Zürich-Altenrhein
20 Montreux-Bern-Zürich
30 Spiez-Meiringen-Brünig-Goldau
40 Genève-Simplonpass-Lugano
50 Basel-Gemmipass-Sion
70 Zürich-Gotthardpass-Lugano
80 Zürich-Lukmanierpass-Biasca
90 Altenrhein-Julierpass-Malojapass-Lugano
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https://en.wikipedia.org/wiki/PhysX
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PhysX is an open-source realtime physics engine middleware SDK developed by Nvidia as a part of Nvidia GameWorks software suite.
Initially, video games supporting PhysX were meant to be accelerated by PhysX PPU (expansion cards designed by Ageia). However, after Ageia's acquisition by Nvidia, dedicated PhysX cards have been discontinued in favor of the API being run on CUDA-enabled GeForce GPUs. In both cases, hardware acceleration allowed for the offloading of physics calculations from the CPU, allowing it to perform other tasks instead.
PhysX and other middleware physics engines are used in many video games today because they free game developers from having to write their own code that implements classical mechanics (Newtonian physics) to do, for example, soft body dynamics.
History
What is known today as PhysX originated as a physics simulation engine called NovodeX. The engine was developed by Swiss company NovodeX AG, an ETH Zurich spin-off. In 2004, Ageia acquired NovodeX AG and began developing a hardware technology that could accelerate physics calculations, aiding the CPU. Ageia called the technology PhysX, the SDK was renamed from NovodeX to PhysX, and the accelerator cards were dubbed PPUs (Physics Processing Units).
In its implementation, the first video game to use PhysX technology is The Stalin Subway, released in Russia-only game stores in September 2005.
In 2008, Ageia was itself acquired by graphics technology manufacturer Nvidia. Nvidia started enabling PhysX hardware acceleration on its line of GeForce graphics cards and eventually dropped support for Ageia PPUs.
PhysX SDK 3.0 was released in May 2011 and represented a significant rewrite of the SDK, bringing improvements such as more efficient multithreading and a unified code base for all supported platforms.
At GDC 2015, Nvidia made the source code for PhysX available on GitHub, but required registration at developer.nvidia.com. The proprietary SDK was provided to developers for free f
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https://en.wikipedia.org/wiki/Inosinic%20acid
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Inosinic acid or inosine monophosphate (IMP) is a nucleotide (that is, a nucleoside monophosphate). Widely used as a flavor enhancer, it is typically obtained from chicken byproducts or other meat industry waste. Inosinic acid is important in metabolism. It is the ribonucleotide of hypoxanthine and the first nucleotide formed during the synthesis of purine nucleotides. It can also be formed by the deamination of adenosine monophosphate by AMP deaminase. It can be hydrolysed to inosine.
The enzyme deoxyribonucleoside triphosphate pyrophosphohydrolase, encoded by YJR069C in Saccharomyces cerevisiae and containing (d)ITPase and (d)XTPase activities, hydrolyzes inosine triphosphate (ITP) releasing pyrophosphate and IMP.
Important derivatives of inosinic acid include the purine nucleotides found in nucleic acids and adenosine triphosphate, which is used to store chemical energy in muscle and other tissues.
In the food industry, inosinic acid and its salts such as disodium inosinate are used as flavor enhancers. It is known as E number reference E630.
Inosinate synthesis
The inosinate synthesis is complex, beginning with a 5-phosphoribosyl-1-pyrophosphate (PRPP). Enzymes taking part in IMP synthesis constitute a multienzyme complex in the cell. Evidence demonstrates that there are multifunctional enzymes, and some of them catalyze non-sequential steps in the pathway.
Synthesis of other purine nucleotides
Within a few steps inosinate becomes AMP or GMP. Both compounds are RNA nucleotides. AMP differs from inosinate by the replacement of IMP's carbon-6 carbonyl with an amino group. The interconversion of AMP and IMP occurs as part of the purine nucleotide cycle. GMP is formed by the inosinate oxidation to xanthylate (XMP), and afterwards adds an amino group on carbon 2. Hydrogen acceptor on inosinate oxidation is NAD+. Finally, carbon 2 gains the amino group by spending an ATP molecule (which becomes AMP+2Pi). While AMP synthesis requires GTP, GMP synthesis uses ATP.
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https://en.wikipedia.org/wiki/ROFOR
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ROFOR is a format for reporting weather information. ROFOR is an abbreviation for "Route Forecast". As the name suggests is the weather forecast of the route of any aircraft which will be flying through the route. ROFOR contains various information regarding date and time of forecast, direction and speed of the wind, aerodrome ICAO code for which the forecast is made, cloud levels and freezing (icing) levels, turbulence and vertical wind shear information.
Example
Example of ROFOR report:
ROFOR 060300Z 0606/0612 KT VIDP 12580 2AC120 4CI300 7///180 403028 27010 405020 28015 407015 30020 410010 33025 523306 631209 11111 12775 40120 22222 38150 27115=
Interpretation of report:
References
Meteorological data and networks
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https://en.wikipedia.org/wiki/Bayesian%20game
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In game theory, a Bayesian game is a strategic decision-making model which assumes players have incomplete information. Players hold private information relevant to the game, meaning that the payoffs are not common knowledge. Bayesian games model the outcome of player interactions using aspects of Bayesian probability. They are notable because they allowed, for the first time in game theory, for the specification of the solutions to games with incomplete information.
Hungarian economist John C. Harsanyi introduced the concept of Bayesian games in three papers from 1967 and 1968: He was awarded the Nobel Memorial Prize in Economic Sciences for these and other contributions to game theory in 1994. Roughly speaking, Harsanyi defined Bayesian games in the following way: players are assigned by nature at the start of the game a set of characteristics. By mapping probability distributions to these characteristics and by calculating the outcome of the game using Bayesian probability, the result is a game whose solution is, for technical reasons, far easier to calculate than a similar game in a non-Bayesian context. For those technical reasons, see the Specification of games section in this article.
Normal form games with incomplete information
Elements
A Bayesian game is defined by (N,A,T,p,u), where it consists of the following elements:
Set of players, N: The set of players within the game
Action sets, ai: The set of actions available to Player i. An action profile a = (a1, . . . , aN) is a list of types, one for each player
Type sets, ti: The set of types of players i. "Types" capture the private information a player can have. A type profile t = (t1, . . . , tN) is a list of types, one for each player
Payoff functions, u: Assign a payoff to a player given their type and the action profiles. A payoff function, u= (u1, . . . , uN) denotes the utilities of player i
Prior, p: A probability distribution over all possible type profiles, where p(t) = p(t1, . . . ,t
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https://en.wikipedia.org/wiki/Normal-form%20game
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In game theory, normal form is a description of a game. Unlike extensive form, normal-form representations are not graphical per se, but rather represent the game by way of a matrix. While this approach can be of greater use in identifying strictly dominated strategies and Nash equilibria, some information is lost as compared to extensive-form representations. The normal-form representation of a game includes all perceptible and conceivable strategies, and their corresponding payoffs, for each player.
In static games of complete, perfect information, a normal-form representation of a game is a specification of players' strategy spaces and payoff functions. A strategy space for a player is the set of all strategies available to that player, whereas a strategy is a complete plan of action for every stage of the game, regardless of whether that stage actually arises in play. A payoff function for a player is a mapping from the cross-product of players' strategy spaces to that player's set of payoffs (normally the set of real numbers, where the number represents a cardinal or ordinal utility—often cardinal in the normal-form representation) of a player, i.e. the payoff function of a player takes as its input a strategy profile (that is a specification of strategies for every player) and yields a representation of payoff as its output.
An example
The matrix provided is a normal-form representation of a game in which players move simultaneously (or at least do not observe the other player's move before making their own) and receive the payoffs as specified for the combinations of actions played. For example, if player 1 plays top and player 2 plays left, player 1 receives 4 and player 2 receives 3. In each cell, the first number represents the payoff to the row player (in this case player 1), and the second number represents the payoff to the column player (in this case player 2).
Other representations
Often, symmetric games (where the payoffs do not depend on whic
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https://en.wikipedia.org/wiki/Enumerator%20polynomial
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In coding theory, the weight enumerator polynomial of a binary linear code specifies the number of words of each possible Hamming weight.
Let be a binary linear code length . The weight distribution is the sequence of numbers
giving the number of codewords c in C having weight t as t ranges from 0 to n. The weight enumerator is the bivariate polynomial
Basic properties
MacWilliams identity
Denote the dual code of by
(where denotes the vector dot product and which is taken over ).
The MacWilliams identity states that
The identity is named after Jessie MacWilliams.
Distance enumerator
The distance distribution or inner distribution of a code C of size M and length n is the sequence of numbers
where i ranges from 0 to n. The distance enumerator polynomial is
and when C is linear this is equal to the weight enumerator.
The outer distribution of C is the 2n-by-n+1 matrix B with rows indexed by elements of GF(2)n and columns indexed by integers 0...n, and entries
The sum of the rows of B is M times the inner distribution vector (A0,...,An).
A code C is regular if the rows of B corresponding to the codewords of C are all equal.
References
Chapters 3.5 and 4.3.
Coding theory
Error detection and correction
Mathematical identities
Polynomials
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https://en.wikipedia.org/wiki/Dual%20code
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In coding theory, the dual code of a linear code
is the linear code defined by
where
is a scalar product. In linear algebra terms, the dual code is the annihilator of C with respect to the bilinear form . The dimension of C and its dual always add up to the length n:
A generator matrix for the dual code is the parity-check matrix for the original code and vice versa. The dual of the dual code is always the original code.
Self-dual codes
A self-dual code is one which is its own dual. This implies that n is even and dim C = n/2. If a self-dual code is such that each codeword's weight is a multiple of some constant , then it is of one of the following four types:
Type I codes are binary self-dual codes which are not doubly even. Type I codes are always even (every codeword has even Hamming weight).
Type II codes are binary self-dual codes which are doubly even.
Type III codes are ternary self-dual codes. Every codeword in a Type III code has Hamming weight divisible by 3.
Type IV codes are self-dual codes over F4. These are again even.
Codes of types I, II, III, or IV exist only if the length n is a multiple of 2, 8, 4, or 2 respectively.
If a self-dual code has a generator matrix of the form , then the dual code has generator matrix , where is the identity matrix and .
References
External links
MATH32031: Coding Theory - Dual Code - pdf with some examples and explanations
Coding theory
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https://en.wikipedia.org/wiki/IL%20%28network%20protocol%29
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The Internet Link protocol or IL is a connection-based transport-layer protocol designed at Bell Labs originally as part of the Plan 9 operating system and is used to carry 9P. It is assigned the Internet Protocol number of 40. It is similar to TCP but much simpler.
Its main features are:
Reliable datagram service
In-sequence delivery
Internetworking using IP
Low complexity, high performance
Adaptive timeouts
As of the Fourth Edition of Plan 9, 2003, IL is deprecated in favor of TCP/IP because it doesn't handle long-distance connections well.
See also
Fast Local Internet Protocol
References
Further reading
—The original paper describing IL
Inferno (operating system)
Internet Protocol based network software
Network protocols
Plan 9 from Bell Labs
Transport layer protocols
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https://en.wikipedia.org/wiki/Hans%20Rademacher
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Hans Adolph Rademacher (; 3 April 1892 – 7 February 1969) was a German-born American mathematician, known for work in mathematical analysis and number theory.
Biography
Rademacher received his Ph.D. in 1916 from Georg-August-Universität Göttingen; Constantin Carathéodory supervised his dissertation. In 1919, he became privatdozent under Constantin Carathéodory at University of Berlin. In 1922, he became an assistant professor at the University of Hamburg, where he supervised budding mathematicians like Theodor Estermann. He was dismissed from his position at the University of Breslau by the Nazis in 1933 due to his public support of the Weimar Republic, and emigrated from Europe in 1934.
After leaving Germany, he moved to Philadelphia and worked at the University of Pennsylvania until his retirement in 1962; he held the Thomas A. Scott Professorship of Mathematics at Pennsylvania from 1956 to 1962. Rademacher had a number of well-known students, including George Andrews, Paul T. Bateman, Theodor Estermann and Emil Grosswald.
Research
Rademacher performed research in analytic number theory, mathematical genetics, the theory of functions of a real variable, and quantum theory. Most notably, he developed the theory of Dedekind sums. In 1937 Rademacher discovered an exact convergent series for the partition function P(n), the number of integer partitions of a number, improving upon Ramanujan's asymptotic non-convergent series and validating Ramanujan's supposition that an exact series representation existed.
Awards and honors
With his retirement from the University of Pennsylvania, a group of mathematicians provided the seed funding for The Hans A. Rademacher Instructorships, and honored him with an honorary degree as Doctor of Science.
Rademacher is the co-author (with Otto Toeplitz) of the popular mathematics book The Enjoyment of Mathematics, published in German in 1930 and still in print.
Works
with Otto Toeplitz: Von Zahlen und Figuren. 1930. 2nd edn. 1933.
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https://en.wikipedia.org/wiki/Nobunaga%27s%20Ambition
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is a series of turn-based grand strategy role-playing simulation video games. The original game was one of the first in its genre, being released in March 1983 by the Japanese video game developer Koei. Nobunaga's Ambition takes place during the Sengoku period of feudal Japan. The player is tasked with achieving the ultimate goal of warlord Oda Nobunaga: the conquest and unification of Japan. Selecting Oda Nobunaga is optional, however, as the player is also able to choose from a variety of other regional daimyōs of the time.
Games in the franchise have been released for the Nintendo Entertainment System, Game Boy, Sega Genesis, 3DO, Super Nintendo, PlayStation, Sega Saturn, PlayStation 2, PlayStation 3, Xbox 360, Wii, PlayStation Portable, PlayStation Vita, PlayStation 4 and Nintendo Switch. The title was also released for Macintosh as well as MSX, Amiga, and MS-DOS. As of March 2018, the series has shipped more than 10 million copies worldwide.
Gameplay
The player may choose from four campaign scenarios, including "Battle for the East" (beginning in 1560), "Daimyo Power Struggles" (1560), "Ambition Untamed" (1571), and "Road Towards Unification" (1582). In each scenario, the player must allocate resources to raise a capable military force, provide a productive economy to support both military and civilian expansion, and support the peasants in order to sustain their respect and loyalty. Gameplay is taken in turns, with each turn in the map view corresponding to a season, and each turn during battle corresponding to a day. The player may achieve victory through numerous means, among which are forcing the enemy to retreat, destroying the enemy command unit, outlasting an invading force, or prolonging battle until the opposing force has exhausted its supplies.
The player can make many choices during the campaign. According to Evan Brooks of Computer Gaming World: "One may transfer soldiers between fiefs, go to war, increase taxes (which causes a decrease in peasan
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https://en.wikipedia.org/wiki/BitTorrent%20tracker
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A BitTorrent tracker is a special type of server that assists in the communication between peers using the BitTorrent protocol.
In peer-to-peer file sharing, a software client on an end-user PC requests a file, and portions of the requested file residing on peer machines are sent to the client, and then reassembled into a full copy of the requested file. The "tracker" server keeps track of where file copies reside on peer machines, which ones are available at time of the client request, and helps coordinate efficient transmission and reassembly of the copied file. Clients that have already begun downloading a file communicate with the tracker periodically to negotiate faster file transfer with new peers, and provide network performance statistics; however, after the initial peer-to-peer file download is started, peer-to-peer communication can continue without the connection to a tracker.
Modern BitTorrent clients may implement a distributed hash table and the peer exchange protocol to discover peers without trackers; however, trackers are still often included with torrents to improve the speed of peer discovery.
Public vs private trackers
Public trackers
Public or open trackers can be used by anyone by adding the tracker address to an existing torrent, or they can be used by any newly created torrent, like OpenBitTorrent. The Pirate Bay operated one of the most popular public trackers until disabling it in 2009 due to legal trouble, and thereafter offered only magnet links.
Private trackers
A private tracker is a BitTorrent tracker that restricts use by requiring users to register with the site. The method for controlling registration used among many private trackers is an invitation system, in which active and contributing members are given the ability to grant a new user permission to register at the site, or a new user goes through an interview process.
Legal issues
Legal uses
There are several circumstances under which it is legal to distribute copyri
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https://en.wikipedia.org/wiki/Signalling%20%28economics%29
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In contract theory, signalling (or signaling; see spelling differences) is the idea that one party (the agent) credibly conveys some information about itself to another party (the principal).
Although signalling theory was initially developed by Michael Spence based on observed knowledge gaps between organisations and prospective employees, its intuitive nature led it to be adapted to many other domains, such as Human Resource Management, business, and financial markets.
In Spence's job-market signaling model, (potential) employees send a signal about their ability level to the employer by acquiring education credentials. The informational value of the credential comes from the fact that the employer believes the credential is positively correlated with having the greater ability and difficulty for low-ability employees to obtain. Thus the credential enables the employer to reliably distinguish low-ability workers from high-ability workers. The concept of signaling is also applicable in competitive altruistic interaction, where the capacity of the receiving party is limited.
Introductory questions
Signalling started with the idea of asymmetric information (a deviation from perfect information), which relates to the fact that, in some economic transactions, inequalities exist in the normal market for the exchange of goods and services. In his seminal 1973 article, Michael Spence proposed that two parties could get around the problem of asymmetric information by having one party send a signal that would reveal some piece of relevant information to the other party. That party would then interpret the signal and adjust their purchasing behaviour accordingly—usually by offering a higher price than if they had not received the signal.
There are, of course, many problems that these parties would immediately run into.
Effort: How much time, energy, or money should the sender (agent) spend on sending the signal?
Reliability: How can the receiver (the principal, who is u
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https://en.wikipedia.org/wiki/Meet-me%20room
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A meet-me room (MMR) is a place within a colocation center (or carrier hotel) where telecommunications companies can physically connect to one another and exchange data without incurring local loop fees. Services provided across connections in an MMR may be voice circuits, data circuits, or Internet Protocol traffic.
An MMR provides a safe production environment where the carrier handover point equipment can be expected to run on a 24/7 basis with minimal risk of interruption. It is typically located within the data center.
To interconnect, companies order a patch from their cage or suite to the MMR and then arrange for the organization running the facility to connect them together. These physical connections may be an optical fiber cable, coaxial cable, twisted pair, or any other networking medium.
Typically, a meet-me room will discourage or disallow customers from installing large amounts of equipment. However, multiplexing equipment is often welcome in the meet-me room, so that a customer can have a single connection between the room and the rest of their equipment in the building, and the multiplexing equipment can then break that out to allow for direct, private connections to several other organizations present in the meet-me room.
An Internet exchange point can also be present in a meet-me room to allow many organizations in the meet-me room to interchange traffic without having to make physical interconnections between every possible pair of organizations.
Examples
One Wilshire: Los Angeles, California
Westin Building: Seattle, Washington
MAE-West (located in Market Post Tower): Downtown San Jose, California
60 Hudson St, New York
111 Eighth Ave, New York
Infomart: Dallas, Texas
350 E. Cermak Rd: Chicago
165 Halsey Street, Newark, New Jersey
399 Chai Wan Road, Hong Kong
References
Internet hosting
Internet architecture
Internet exchange points
Telecommunications infrastructure
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https://en.wikipedia.org/wiki/Electronic%20filter
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Electronic filters are a type of signal processing filter in the form of electrical circuits. This article covers those filters consisting of lumped electronic components, as opposed to distributed-element filters. That is, using components and interconnections that, in analysis, can be considered to exist at a single point. These components can be in discrete packages or part of an integrated circuit.
Electronic filters remove unwanted frequency components from the applied signal, enhance wanted ones, or both. They can be:
passive or active
analog or digital
high-pass, low-pass, band-pass, band-stop (band-rejection; notch), or all-pass.
discrete-time (sampled) or continuous-time
linear or non-linear
infinite impulse response (IIR type) or finite impulse response (FIR type)
The most common types of electronic filters are linear filters, regardless of other aspects of their design. See the article on linear filters for details on their design and analysis.
History
The oldest forms of electronic filters are passive analog linear filters, constructed using only resistors and capacitors or resistors and inductors. These are known as RC and RL single-pole filters respectively. However, these simple filters have very limited uses. Multipole LC filters provide greater control of response form, bandwidth and transition bands. The first of these filters was the constant k filter, invented by George Campbell in 1910. Campbell's filter was a ladder network based on transmission line theory. Together with improved filters by Otto Zobel and others, these filters are known as image parameter filters. A major step forward was taken by Wilhelm Cauer who founded the field of network synthesis around the time of World War II. Cauer's theory allowed filters to be constructed that precisely followed some prescribed frequency function.
Classification by technology
Passive filters
Passive implementations of linear filters are based on combinations of resistors (R), induc
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https://en.wikipedia.org/wiki/Open%20Cluster%20Framework
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Open Cluster Framework (OCF) is a set of standards for computer clustering.
The project started as a working group of the Free Standards Group, now part of the Linux Foundation. Original supporters included several computing companies and groups, including Compaq, Conectiva, IBM, Linux-HA, MSC Software, the Open Source Development Lab, OSCAR, Red Hat, SGI and SUSE.
OCF Resource agents are currently supported by Linux-HA Heartbeat, the high-availability cluster software.
References
External links
OCF website
Cluster computing
Free system software
High-availability cluster computing
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https://en.wikipedia.org/wiki/Slope%20field
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A slope field (also called a direction field) is a graphical representation of the solutions to a first-order differential equation of a scalar function. Solutions to a slope field are functions drawn as solid curves. A slope field shows the slope of a differential equation at certain vertical and horizontal intervals on the x-y plane, and can be used to determine the approximate tangent slope at a point on a curve, where the curve is some solution to the differential equation.
Definition
Standard case
The slope field can be defined for the following type of differential equations
which can be interpreted geometrically as giving the slope of the tangent to the graph of the differential equation's solution (integral curve) at each point (x, y) as a function of the point coordinates.
It can be viewed as a creative way to plot a real-valued function of two real variables as a planar picture. Specifically, for a given pair , a vector with the components is drawn at the point on the -plane. Sometimes, the vector is normalized to make the plot better looking for a human eye. A set of pairs making a rectangular grid is typically used for the drawing.
An isocline (a series of lines with the same slope) is often used to supplement the slope field. In an equation of the form , the isocline is a line in the -plane obtained by setting equal to a constant.
General case of a system of differential equations
Given a system of differential equations,
the slope field is an array of slope marks in the phase space (in any number of dimensions depending on the number of relevant variables; for example, two in the case of a first-order linear ODE, as seen to the right). Each slope mark is centered at a point and is parallel to the vector
The number, position, and length of the slope marks can be arbitrary. The positions are usually chosen such that the points make a uniform grid. The standard case, described above, represents . The general case of the slope field for
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https://en.wikipedia.org/wiki/Linear%20code
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In coding theory, a linear code is an error-correcting code for which any linear combination of codewords is also a codeword. Linear codes are traditionally partitioned into block codes and convolutional codes, although turbo codes can be seen as a hybrid of these two types. Linear codes allow for more efficient encoding and decoding algorithms than other codes (cf. syndrome decoding).
Linear codes are used in forward error correction and are applied in methods for transmitting symbols (e.g., bits) on a communications channel so that, if errors occur in the communication, some errors can be corrected or detected by the recipient of a message block. The codewords in a linear block code are blocks of symbols that are encoded using more symbols than the original value to be sent. A linear code of length n transmits blocks containing n symbols. For example, the [7,4,3] Hamming code is a linear binary code which represents 4-bit messages using 7-bit codewords. Two distinct codewords differ in at least three bits. As a consequence, up to two errors per codeword can be detected while a single error can be corrected. This code contains 24=16 codewords.
Definition and parameters
A linear code of length n and dimension k is a linear subspace C with dimension k of the vector space where is the finite field with q elements. Such a code is called a q-ary code. If q = 2 or q = 3, the code is described as a binary code, or a ternary code respectively. The vectors in C are called codewords. The size of a code is the number of codewords and equals qk.
The weight of a codeword is the number of its elements that are nonzero and the distance between two codewords is the Hamming distance between them, that is, the number of elements in which they differ. The distance d of the linear code is the minimum weight of its nonzero codewords, or equivalently, the minimum distance between distinct codewords. A linear code of length n, dimension k, and distance d is called an [n,
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https://en.wikipedia.org/wiki/Nonlinear%20filter
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In signal processing, a nonlinear (or non-linear) filter is a filter whose output is not a linear function of its input. That is, if the filter outputs signals R and S for two input signals r and s separately, but does not always output αR + βS when the input is a linear combination αr + βs.
Both continuous-domain and discrete-domain filters may be nonlinear. A simple example of the former would be an electrical device whose output voltage R(t) at any moment is the square of the input voltage r(t); or which is the input clipped to a fixed range [a,b], namely R(t) = max(a, min(b, r(t))). An important example of the latter is the running-median filter, such that every output sample Ri is the median of the last three input samples ri, ri−1, ri−2. Like linear filters, nonlinear filters may be shift invariant or not.
Non-linear filters have many applications, especially in the removal of certain types of noise that are not additive. For example, the median filter is widely used to remove spike noise — that affects only a small percentage of the samples, possibly by very large amounts. Indeed, all radio receivers use non-linear filters to convert kilo- to gigahertz signals to the audio frequency range; and all digital signal processing depends on non-linear filters (analog-to-digital converters) to transform analog signals to binary numbers.
However, nonlinear filters are considerably harder to use and design than linear ones, because the most powerful mathematical tools of signal analysis (such as the impulse response and the frequency response) cannot be used on them. Thus, for example, linear filters are often used to remove noise and distortion that was created by nonlinear processes, simply because the proper non-linear filter would be too hard to design and construct.
From the foregoing, we can know that the nonlinear filters have quite different behavior compared to linear filters. The most important characteristic is that, for nonlinear filters, the filte
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https://en.wikipedia.org/wiki/Canonical%20ring
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In mathematics, the pluricanonical ring of an algebraic variety V (which is nonsingular), or of a complex manifold, is the graded ring
of sections of powers of the canonical bundle K. Its nth graded component (for ) is:
that is, the space of sections of the n-th tensor product Kn of the canonical bundle K.
The 0th graded component is sections of the trivial bundle, and is one-dimensional as V is projective. The projective variety defined by this graded ring is called the canonical model of V, and the dimension of the canonical model is called the Kodaira dimension of V.
One can define an analogous ring for any line bundle L over V; the analogous dimension is called the Iitaka dimension. A line bundle is called big if the Iitaka dimension equals the dimension of the variety.
Properties
Birational invariance
The canonical ring and therefore likewise the Kodaira dimension is a birational invariant: Any birational map between smooth compact complex manifolds induces an isomorphism between the respective canonical rings. As a consequence one can define the Kodaira dimension of a singular space as the Kodaira dimension of a desingularization. Due to the birational invariance this is well defined, i.e., independent of the choice of the desingularization.
Fundamental conjecture of birational geometry
A basic conjecture is that the pluricanonical ring is finitely generated. This is considered a major step in the Mori program.
proved this conjecture.
The plurigenera
The dimension
is the classically defined n-th plurigenus of V. The pluricanonical divisor , via the corresponding linear system of divisors, gives a map to projective space , called the n-canonical map.
The size of R is a basic invariant of V, and is called the Kodaira dimension.
Notes
References
Algebraic geometry
Birational geometry
Structures on manifolds
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https://en.wikipedia.org/wiki/Puffed%20grain
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Puffed grains are grains that have been expanded ("puffed") through processing. They have been made for centuries with the simplest methods like popping popcorn. Modern puffed grains are often created using high temperature, pressure, or extrusion.
People eat puffed grains in many ways, but it can be as simple as puffed grain alone and with sugar or salt for taste. Commercial products such as corn flakes and Corn Pops mix many ingredients into a homogeneous batter. The batter is then formed into shapes then toasted and/or extruded. This causes them to rise, but not puff or pop. Puffed grains can be healthful if plain, but when other ingredients are mixed with them they may lose some of their health benefits.
Puffed grains are popular as breakfast cereals and in the form of rice cakes. While it is easy to recognize that cereals came from whole grains, the expansion factor for rice cakes is even greater, and the final product is somewhat more homogeneous.
History
The oldest puffed grain was found in west-central New Mexico in 1948 and 1950. Ears of popcorn were found that were up to 4,000 years old. These pieces of puffed grain were smaller than a penny to two inches in size and can be made in a similar way to popping popcorn.
Rice has been puffed since ancient times using a technique called hot salt frying in which parboiled rice (e.g. steamed and then dried) is puffed by preheated salt.
The modern process of making puffed grains was invented by Dr. Alexander P. Anderson in 1901 in Red Wing, Minnesota. He was doing an experiment dealing with the effect of heat and pressure on corn starch granules where he put them in six glass tubes, sealed them, and put them in an oven until they changed color. When Dr. Anderson took them out and cracked them open an explosion happened; he had made the corn starch turn into a puffed, white mass.
Dr. Anderson's invention of puffed grain was first introduced at the World's Fair in St. Louis in 1904. The puffed grain was shot fro
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https://en.wikipedia.org/wiki/Canopy%20research
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Canopy research is the field of scientific research based upon data collected in the canopy of trees.
Objects
Description of plant and animal species residing in the tree-summits. Mainly ancient forests and tropical forests are studied.
Study of forest ecosystem dynamics, change drivers and other factors that shape forest systems.
Collection of meteorological data. Meteorological studies can help researchers measure the efficacy of forest canopies in offsetting global climate change. Researchers at the Agricultural Research Service have calibrated a model for forest canopies that measures and estimates the amount of carbon a forest canopy absorbs/releases due to photosynthesis/respiration. The research found that the forest canopy shifted from a carbon “sink” (of net carbon absorption due to photosynthesis) to a carbon “source” (of net carbon respiration) following the defoliation of the canopy due to the gypsy moth. This research helps scientists determine the role of trees in offsetting carbon released into the atmosphere, which contributes to global warming, and the biological influences that impact it.
Chief discoveries
90% of animal and 50% of plant species in tropical rainforests live in the upper levels of the large trees. As many as 1000 different insects have been collected from one tree.
Tropical forests require a minimum area to develop their crucial micro climate and to provide habitats for larger mammals.
While grown forests continue to store carbon dioxide, young forests store up ten times more.
Canopy research is a relatively new scientific field which was hampered for a long time by lack of means of access to the tree canopies and lack of appropriate means of housing researchers.
Climbing gear, tree houses, canopy walkways, cranes, airships and inflatable platforms resting on the treetops have lately overcome these barriers.
Cranes have proven to offer the best three-dimensional access. The effort to set them up is worthwhile, as m
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https://en.wikipedia.org/wiki/Joule%20expansion
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The Joule expansion (also called free expansion) is an irreversible process in thermodynamics in which a volume of gas is kept in one side of a thermally isolated container (via a small partition), with the other side of the container being evacuated. The partition between the two parts of the container is then opened, and the gas fills the whole container.
The Joule expansion, treated as a thought experiment involving ideal gases, is a useful exercise in classical thermodynamics. It provides a convenient example for calculating changes in thermodynamic quantities, including the resulting increase in entropy of the universe (entropy production) that results from this inherently irreversible process. An actual Joule expansion experiment necessarily involves real gases; the temperature change in such a process provides a measure of intermolecular forces.
This type of expansion is named after James Prescott Joule who used this expansion, in 1845, in his study for the mechanical equivalent of heat, but this expansion was known long before Joule e.g. by John Leslie, in the beginning of the 19th century, and studied by Joseph-Louis Gay-Lussac in 1807 with similar results as obtained by Joule.
The Joule expansion should not be confused with the Joule–Thomson expansion or throttling process which refers to the steady flow of a gas from a region of higher pressure to one of lower pressure via a valve or porous plug.
Description
The process begins with gas under some pressure, , at temperature , confined to one half of a thermally isolated container (see the top part of the drawing at the beginning of this article). The gas occupies an initial volume , mechanically separated from the other part of the container, which has a volume , and is under near zero pressure. The tap (solid line) between the two halves of the container is then suddenly opened, and the gas expands to fill the entire container, which has a total volume of (see the bottom part of the drawing). A therm
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https://en.wikipedia.org/wiki/Quantum%20sort
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A quantum sort is any sorting algorithm that runs on a quantum computer. Any comparison-based quantum sorting algorithm would take at least steps, which is already achievable by classical algorithms. Thus, for this task, quantum computers are no better than classical ones, and should be disregarded when it comes to time complexity. However, in space-bounded sorts, quantum algorithms outperform their classical counterparts.
References
Sorting algorithms
Quantum algorithms
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https://en.wikipedia.org/wiki/Cross-browser%20compatibility
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Cross-browser compatibility is the ability of a website or web application to function across different browsers and degrade gracefully when browser features are absent or lacking.
History
Background
The history of cross-browser is involved with the history of the "browser wars" in the late 1990s between Netscape Navigator and Microsoft Internet Explorer as well as with that of JavaScript and JScript, the first scripting languages to be implemented in the web browsers. Netscape Navigator was the most widely used web browser at that time and Microsoft had licensed Mosaic to create Internet Explorer 1.0. New versions of Netscape Navigator and Internet Explorer were released at a rapid pace over the following few years. Due to the intense competition in the web browser market, the development of these browsers was fast-paced and new features were added without any coordination between vendors. The introduction of new features often took priority over bug fixes, resulting in unstable browsers, fickle web standards compliance, frequent crashes and many security holes.
Creation of W3C and Web standardization
The World Wide Web Consortium (W3C), founded in 1994 to promote open standards for the World Wide Web, pulled Netscape and Microsoft together with other companies to develop a standard for browser scripting languages called ECMAScript. The first version of the standard was published in 1997. Subsequent releases of JavaScript and JScript would implement the ECMAScript standard for greater cross-browser compatibility. After the standardization of ECMAScript, W3C began work on the standardization of Document Object Model (DOM), which is a way of representing and interacting with objects in HTML, XHTML and XML documents. DOM Level 0 and DOM Level 1 were introduced in 1996 and 1997. Only limited supports of these were implemented by the browsers, as a result, non-conformant browsers such as Internet Explorer 4.x and Netscape 4.x were still widely used as late as 2000
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https://en.wikipedia.org/wiki/MicroEmpix
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MicroEmpix is the microkernel (much nearer to an exokernel) version of Empix, an operating system (OS) developed at the Computing Systems Laboratory (CSLab) of the Electrical & Computer Engineering department at the National Technical University of Athens.
Empix began in the late 1980's as the laboratory's effort to write a small Unix-like modern multitasking OS, intended for educational use. Borrowing most of its basic characteristics (file system, binary format, shell) from other popular OSes of the time (Xinu, Minix, DOS). Empix is quite small (about 10,000 lines of code) and supports Intel x86 processors, in the IBM Personal Computers (PC) XT (8088), and AT (80286) architectures, floppy disks and hard disk drives (with the File Allocation Table (FAT) 16 limits), and Enhanced Graphics Adapter (EGA) graphics (80x25 color terminal) and the serial ports. It has a shell with some basic commands, and the ability to execute multiple processes.
MicroEmpix is far different. It's about 1,600 lines of code (over which about 1,000 devoted to serial port control), and it's a microkernel, meaning that it creates and runs processes in kernel-space, with no distinction between process-space and kernel space. What the kernel sees, the process sees and vice versa. No system calls occur to require a system call dispatcher or a similar mechanism. Kernel functions are inherent to the processes created, and there is but one user.
References
External links
The MicroEmpix Fan Site
Microkernels
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https://en.wikipedia.org/wiki/Leading%20zero
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A leading zero is any 0 digit that comes before the first nonzero digit in a number string in positional notation. For example, James Bond's famous identifier, 007, has two leading zeros. Any zeroes appearing to the left of the first non-zero digit (of any integer or decimal) do not affect its value, and can be omitted (or replaced with blanks) with no loss of information. Therefore, the usual decimal notation of integers does not use leading zeros except for the zero itself, which would be denoted as an empty string otherwise. However, in decimal fractions strictly between −1 and 1, the leading zeros digits between the decimal point and the first nonzero digit are necessary for conveying the magnitude of a number and cannot be omitted, while trailing zeros – zeros occurring after the decimal point and after the last nonzero digit – can be omitted without changing the meaning.
Occurrence
Often, leading zeros are found on non-electronic digital displays or on such electronic ones as seven-segment displays, that contain fixed sets of digits. These devices include manual counters, stopwatches, odometers, and digital clocks. Leading zeros are also generated by many older computer programs when creating values to assign to new records, accounts and other files, and as such are likely to be used by utility billing systems, human resources information systems and government databases. Many digital cameras and other electronic media recording devices use leading zeros when creating and saving new files to make names of the equal length.
Leading zeros are also present whenever the number of digits is fixed by the technical system (such as in a memory register), but the stored value is not large enough to result in a non-zero most significant digit. The count leading zeros operation efficiently determines the number of leading zero bits in a machine word.
A leading zero appears in roulette in the United States, where "00" is distinct from "0" (a wager on "0" will not win
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https://en.wikipedia.org/wiki/KTXH
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KTXH (channel 20), branded on-air as My 20 Vision, is a television station in Houston, Texas, United States, serving as the local outlet for the MyNetworkTV programming service. It is owned and operated by Fox Television Stations alongside Fox outlet KRIV (channel 26). Both stations share studios on Southwest Freeway (I-69/US 59) in Houston, while KTXH's transmitter is located near Missouri City, Texas.
KTXH began broadcasting in November 1982 as Houston's third independent station. A month after going on air, its broadcast tower collapsed in a construction accident that killed five people. The station recovered and emerged as Houston's sports independent, beginning long associations with the Houston Astros and Houston Rockets that continued uninterrupted through the late 1990s and sporadically until the early 2010s. Not long after starting up, KTXH was sold twice in rapid succession for large amounts. However, when the independent station trade, advertising market, and regional economy cooled, it was sold again for less than half of its previous value. The Paramount Stations Group acquired KTXH and other stations in two parts between 1989 and 1991, bringing much-needed stability.
KTXH was one of several Paramount-owned stations to be charter outlets for the United Paramount Network (UPN) in 1995; in 2001, after UPN was acquired by CBS, Fox took possession of the station in a trade and merged its operations with KRIV. When UPN merged into The CW in 2006, bypassing all of Fox's UPN and independent stations in the process, the station became part of Fox's MyNetworkTV service. In 2021, the station became one of two ATSC 3.0 (NextGen TV) transmitters for the Houston area; its subchannels are now transmitted by other local stations on its behalf.
History
Construction, start-up, and tragedy
Interest in channel 20 in Houston began to emerge in 1976, as three groups filed applications for new television stations in light of the emerging technology of subscription televi
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https://en.wikipedia.org/wiki/Symmetrical%20components
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In electrical engineering, the method of symmetrical components simplifies analysis of unbalanced three-phase power systems under both normal and abnormal conditions. The basic idea is that an asymmetrical set of N phasors can be expressed as a linear combination of N symmetrical sets of phasors by means of a complex linear transformation. Fortescue's theorem (symmetrical components) is based on superposition principle, so it is applicable to linear power systems only, or to linear approximations of non-linear power systems.
In the most common case of three-phase systems, the resulting "symmetrical" components are referred to as direct (or positive), inverse (or negative) and zero (or homopolar). The analysis of power system is much simpler in the domain of symmetrical components, because the resulting equations are mutually linearly independent if the circuit itself is balanced.
Description
In 1918 Charles Legeyt Fortescue presented a paper which demonstrated that any set of N unbalanced phasors (that is, any such polyphase signal) could be expressed as the sum of N symmetrical sets of balanced phasors, for values of N that are prime. Only a single frequency component is represented by the phasors.
In 1943 Edith Clarke published a textbook giving a method of use of symmetrical components for three-phase systems that greatly simplified calculations over the original Fortescue paper. In a three-phase system, one set of phasors has the same phase sequence as the system under study (positive sequence; say ABC), the second set has the reverse phase sequence (negative sequence; ACB), and in the third set the phasors A, B and C are in phase with each other (zero sequence, the common-mode signal). Essentially, this method converts three unbalanced phases into three independent sources, which makes asymmetric fault analysis more tractable.
By expanding a one-line diagram to show the positive sequence, negative sequence, and zero sequence impedances of generators, tra
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https://en.wikipedia.org/wiki/SLOSS%20debate
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The SLOSS debate was a debate in ecology and conservation biology during the 1970's and 1980's as to whether a single large or several small (SLOSS) reserves were a superior means of conserving biodiversity in a fragmented habitat. Since its inception, multiple alternate theories have been proposed. There have been applications of the concept outside of the original context of habitat conservation.
History
In 1975, Jared Diamond suggested some "rules" for the design of protected areas, based on Robert MacArthur and E. O. Wilson's book The Theory of Island Biogeography. One of his suggestions was that a single large reserve was preferable to several smaller reserves whose total areas were equal to the larger.
Since species richness increases with habitat area, as established by the species area curve, a larger block of habitat would support more species than any of the smaller blocks. This idea was popularised by many other ecologists, and has been incorporated into most standard textbooks in conservation biology, and was used in real-world conservation planning. This idea was challenged by Wilson's former student Daniel Simberloff, who pointed out that this idea relied on the assumption that smaller reserves had a nested species composition — it assumed that each larger reserve had all the species presented in any smaller reserve. If the smaller reserves had unshared species, then it was possible that two smaller reserves could have more species than a single large reserve.
Simberloff and Abele expanded their argument in subsequent paper in the journal The American Naturalist stating neither ecological theory nor empirical data exist to support the hypothesis that subdividing a nature reserve would increase extinction rates, basically negating Diamond as well as MacArthur and Wilson. Bruce A. Wilcox and Dennis D. Murphy responded with a key paper "Conservation strategy - effects of fragmentation on extinction" pointing out flaws in their argument while prov
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https://en.wikipedia.org/wiki/Volume-weighted%20average%20price
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In finance, volume-weighted average price (VWAP) is the ratio of the value of a security or financial asset traded to the total volume of transactions during a trading session. It is a measure of the average trading price for the period.
Typically, the indicator is computed for one day, but it can be measured between any two points in time.
VWAP is often used as a trading benchmark by investors who aim to be as passive as possible in their execution. Many pension funds, and some mutual funds, fall into this category. The aim of using a VWAP trading target is to ensure that the trader executing the order does so in line with the volume on the market. It is sometimes argued that such execution reduces transaction costs by minimizing market impact costs (the additional cost due to the market impact, i.e. the adverse effect of a trader's activities on the price of a security).
VWAP is often used in algorithmic trading. A broker may guarantee the execution of an order at the VWAP and have a computer program enter the orders into the market to earn the trader's commission and create P&L. This is called a guaranteed VWAP execution. The broker can also trade in a best effort way and answer the client with the realized price. This is called a VWAP target execution; it incurs more dispersion in the answered price compared to the VWAP price for the client but a lower received/paid commission. Trading algorithms that use VWAP as a target belong to a class of algorithms known as volume participation algorithms.
The first execution based on the VWAP was in 1984 for the Ford Motor Company by James Elkins, then head trader at Abel Noser.
Formula
VWAP is calculated using the following formula:
where:
is Volume Weighted Average Price;
is price of trade ;
is quantity of trade ;
is each individual trade that takes place over the defined period of time, excluding cross trades and basket cross trades.
Using the VWAP
The VWAP can be used similar to moving averages, where prices
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https://en.wikipedia.org/wiki/SEMI
|
SEMI is an industry association comprising companies involved in the electronics design and manufacturing supply chain. They provide equipment, materials and services for the manufacture of semiconductors, photovoltaic panels, LED and flat panel displays, micro-electromechanical systems (MEMS), printed and flexible electronics, and related micro and nano-technologies.
SEMI is headquartered in Milpitas, California, and has offices in Bangalore; Berlin; Brussels; Hsinchu; Seoul; Shanghai; Singapore; Tokyo; and Washington, D.C. Its main activities include conferences and trade shows, development of industry standards, market research reporting, and industry advocacy. The president and chief executive officer of the organization is Ajit Manocha.
Global advocacy
SEMI Global Advocacy represents the interests of the semiconductor industry's design, manufacturing and supply chain businesses worldwide. SEMI promotes its positions on public issues via press releases, position papers, presentations, social media, web content, and media interviews.
SEMI Global Advocacy focuses on five priorities: taxes, trade, technology, talent, and environment, health and safety (EHS).
Workforce development
SEMI Workforce Development attracts, and develops talent that can fulfill the requirements of the electronics industry. SEMI programs include:
SEMI Works. Begun in 2019, SEMI Works develops a standardized process that identifies technical competencies and certifies relevant college coursework. The program is designed to improve the job hiring process for both applicants and employers.
Diversity and Inclusion Council. This council communicates best practices and benefits arising from diverse and inclusive cultures, using white papers, services, webinars, workshops, presentations and events.
SEMI standards
The SEMI Standards program was established in 1973 using proceeds from the west coast SEMICON show. Its first initiative, following meetings with silicon suppliers, was a succe
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https://en.wikipedia.org/wiki/Phaser%20%28effect%29
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A phaser is an electronic sound processor used to filter a signal by creating a series of peaks and troughs in the frequency spectrum. The position of the peaks and troughs of the waveform being affected is typically modulated by an internal low-frequency oscillator so that they vary over time, creating a sweeping effect.
Phasers are often used to give a "synthesized" or electronic effect to natural sounds, such as human speech. The voice of C-3PO from Star Wars was created by taking the actor's voice and treating it with a phaser.
Process
The electronic phasing effect is created by splitting an audio signal into two paths. One path treats the signal with an all-pass filter, which preserves the amplitude of the original signal and alters the phase. The amount of change in phase depends on the frequency. When signals from the two paths are mixed, the frequencies that are out of phase will cancel each other out, creating the phaser's characteristic notches. Changing the mix ratio changes the depth of the notches; the deepest notches occur when the mix ratio is 50%.
The definition of phaser typically excludes such devices where the all-pass section is a delay line; such a device is called a flanger. Using a delay line creates an unlimited series of equally spaced notches and peaks. It is possible to cascade a delay line with another type of all-pass filter. This combines the unlimited number of notches from the flanger with the uneven spacing of the phaser.
Structure
Traditional electronic phasers use a series of variable all-pass phase-shift networks which alter the phases of the different frequency components in the signal. These networks pass all frequencies at equal volume, introducing only phase change to the signal. Human ears are not very responsive to phase differences, but this creates audible interferences when mixed back with the dry (unprocessed) signal, creating notches. The simplified structure of a mono phaser is shown below:
The number of all-pas
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https://en.wikipedia.org/wiki/Jigdo
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Jigdo (a portmanteau of "Jigsaw" and "download") is a utility typically used for downloading to piece together a large file, most commonly an optical disk image such as a CD, DVD or Blu-ray Disc (BD) image, from many smaller individual constituent files. The constituent files may be local and/or retrieved from one or more mirror sites. Jigdo's features are similar to BitTorrent, but unlike BitTorrent, Jigdo uses a client-server model, not peer-to-peer.
Jigdo itself is quite portable and is available for many UNIX and Unix-like operating systems,
and is also available for Microsoft Windows.
Released under the terms of the GPL-2.0-only license, Jigdo is free software.
Uses
A quite common use would be to construct a Linux CD or DVD image for installation or distribution, where a slightly older version or release of same, or a cache or local partial mirror, already contains some or many of the needed constituent files. That would typically proceed as follows: Jigdo would be invoked using the jigdo-lite command, with a command line argument of the URL of a ".jigdo" file. Jigdo would then download that file, and after examining its contents, would also download a ".template" file. After inspecting the ".template" file, Jigdo would prompt for the location of files to scan. The user would then either enter or select from a list the location of files to scan. Jigdo would scan that location for any files that match any of the needed constituent files. Any matching files would be used in constructing the target image. Jigdo prompts again, and if the user gives a location, the process repeats - giving Jigdo the opportunity to scan multiple locations for the needed files. If the user enters no location, Jigdo proceeds to download any unmatched constituent files and to use them to assemble the target image file.
The jigdo-file utility is generally used to create the ".jigdo" and ".template" files needed to create target images using Jigdo.
Presently at least
Debian and Ubu
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https://en.wikipedia.org/wiki/TNT%20%28instant%20messenger%29
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TNT is an open source instant messaging client which is designed to use AIM and uses the AOL TOC protocol. The client is run within Emacs or XEmacs and is written in Emacs Lisp.
The client was originally written for AOL, but the project was abandoned around 1999, along with its other TOC clients, TiK and TAC. Since then, independent developers have continued to add features and make new releases.
TNT has been revised to work with the TOC2 protocol.
See also
Comparison of cross-platform instant messaging clients
External links
TNT independent development project site
Instant messaging clients
AIM (software) clients
Unix instant messaging clients
Instant messaging clients for Linux
Windows instant messaging clients
MacOS instant messaging clients
Cross-platform software
|
https://en.wikipedia.org/wiki/Cobweb%20plot
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A cobweb plot, or Verhulst diagram is a visual tool used in the dynamical systems field of mathematics to investigate the qualitative behaviour of one-dimensional iterated functions, such as the logistic map. Using a cobweb plot, it is possible to infer the long term status of an initial condition under repeated application of a map.
Method
For a given iterated function , the plot consists of a diagonal () line and a curve representing . To plot the behaviour of a value , apply the following steps.
Find the point on the function curve with an x-coordinate of . This has the coordinates ().
Plot horizontally across from this point to the diagonal line. This has the coordinates ().
Plot vertically from the point on the diagonal to the function curve. This has the coordinates ().
Repeat from step 2 as required.
Interpretation
On the cobweb plot, a stable fixed point corresponds to an inward spiral, while an unstable fixed point is an outward one. It follows from the definition of a fixed point that these spirals will center at a point where the diagonal y=x line crosses the function graph. A period 2 orbit is represented by a rectangle, while greater period cycles produce further, more complex closed loops. A chaotic orbit would show a 'filled out' area, indicating an infinite number of non-repeating values.
See also
Jones diagram – similar plotting technique
Fixed-point iteration – iterative algorithm to find fixed points (produces a cobweb plot)
References
Plots (graphics)
Dynamical systems
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https://en.wikipedia.org/wiki/CPN-AMI
|
CPN-AMI is a computer-aided software engineering environment based on Petri Net specifications. It provides the ability to specify the behavior of a distributed system—and to evaluate properties such as invariants (preservation of resources), absence of deadlocks, liveness, or temporal logic properties (relations between events in the system).
CPN-AMI relies on AMI-Nets, that are well-formed Petri nets with syntactic facilities. Well Formed Petri nets were jointly elaborated between the University of Paris 6 (Université P. & M. Curie) and the University of Torino in the early 1990s. This Petri net class supports symbolic techniques for model checking, and thus provides a very compressed way to store all states of a system.
Since 2016 CPN-AMI has been listed by the owners as "still available but not maintained any more" ().
See also
Well-formed Petri net
Petriscript
References
External links
More information about CPN-AMI.
BNF of AMI-Net
References
Integrated development environments
Formal methods tools
Petri nets
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https://en.wikipedia.org/wiki/Geotagging
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Geotagging, or GeoTagging, is the process of adding geographical identification metadata to various media such as a geotagged photograph or video, websites, SMS messages, QR Codes or RSS feeds and is a form of geospatial metadata. This data usually consists of latitude and longitude coordinates, though they can also include altitude, bearing, distance, accuracy data, and place names, and perhaps a time stamp.
Geotagging can help users find a wide variety of location-specific information from a device. For instance, someone can find images taken near a given location by entering latitude and longitude coordinates into a suitable image search engine. Geotagging-enabled information services can also potentially be used to find location-based news, websites, or other resources. Geotagging can tell users the location of the content of a given picture or other media or the point of view, and conversely on some media platforms show media relevant to a given location.
The geographical location data used in geotagging can, in almost every case, be derived from the global positioning system, and based on a latitude/longitude-coordinate system that presents each location on the earth from 180° west through 180° east along the Equator and 90° north through 90° south along the prime meridian.
The related term geocoding refers to the process of taking non-coordinate-based geographical identifiers, such as a street address, and finding associated geographic coordinates (or vice versa for reverse geocoding). Such techniques can be used together with geotagging to provide alternative search techniques.
Applications
In social media
Geotagging is a popular feature on several social media platforms, such as Facebook and Instagram.
Facebook users can geotag photos that can be added to the page of the location they are tagging. Users may also use a feature that allows them to find nearby Facebook friends by generating a list of people according to the location tracker in their
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https://en.wikipedia.org/wiki/Magnaporthe%20grisea
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Magnaporthe grisea, also known as rice blast fungus, rice rotten neck, rice seedling blight, blast of rice, oval leaf spot of graminea, pitting disease, ryegrass blast, Johnson spot, neck blast, wheat blast and , is a plant-pathogenic fungus and model organism that causes a serious disease affecting rice. It is now known that M. grisea consists of a cryptic species complex containing at least two biological species that have clear genetic differences and do not interbreed. Complex members isolated from Digitaria have been more narrowly defined as M. grisea. The remaining members of the complex isolated from rice and a variety of other hosts have been renamed Magnaporthe oryzae, within the same M. grisea complex. Confusion on which of these two names to use for the rice blast pathogen remains, as both are now used by different authors.
Members of the M. grisea complex can also infect other agriculturally important cereals including wheat, rye, barley, and pearl millet causing diseases called blast disease or blight disease. Rice blast causes economically significant crop losses annually. Each year it is estimated to destroy enough rice to feed more than 60 million people. The fungus is known to occur in 85 countries worldwide and was the most devastating fungal plant pathogen in the world.
Hosts and symptoms
M. grisea is an ascomycete fungus. It is an extremely effective plant pathogen as it can reproduce both sexually and asexually to produce specialized infectious structures known as appressoria that infect aerial tissues and hyphae that can infect root tissues.
Rice blast has been observed on rice strains M-201, M-202, M-204, M-205, M-103, M-104, S-102, L-204, Calmochi-101, with M-201 being the most vulnerable. Initial symptoms are white to gray-green lesions or spots with darker borders produced on all parts of the shoot, while older lesions are elliptical or spindle-shaped and whitish to gray with necrotic borders. Lesions may enlarge and coalesce to kil
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https://en.wikipedia.org/wiki/VT180
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The VT180 is a personal computer produced by Digital Equipment Corporation (DEC) of Maynard, Massachusetts, USA.
Introduced in early 1982, the CP/M-based VT180 was DEC's entry-level microcomputer. "VT180" is the unofficial name for the combination of the VT100 computer terminal and VT18X option. The VT18X includes a 2 MHz Zilog Z80 microprocessor and 64K RAM on two circuit boards that fit inside the terminal, and two external 5.25-inch floppy disk drives with room for two more in an external enclosure. The VT180 was codenamed "Robin".
Digital later released a full-fledged personal computer known as the Rainbow 100 as the successor to Robin.
When Digital ended the VT100 terminal family in 1983, it also discontinued the VT180. No direct replacement was offered, although the Rainbow 100 eventually provided a superset of Robin's functionality.
References
External links
DEC Robin, DigiBarn Computer Museum
DEC VT180, Terminals Wiki
Character-oriented terminal
DEC computer terminals
8-bit computers
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https://en.wikipedia.org/wiki/Sticky%20bit
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In computing, the sticky bit is a user ownership access right flag that can be assigned to files and directories on Unix-like systems.
There are two definitions: one for files, one for directories.
For files, particularly executables, superuser could tag these as to be retained in main memory, even when their need ends, to minimize swapping that would occur when another need arises, and the file now has to be reloaded from relatively slow secondary memory. This function has become obsolete due to swapping optimization.
For directories, when a directory's sticky bit is set, the filesystem treats the files in such directories in a special way so only the file's owner, the directory's owner, or root user can rename or delete the file. Without the sticky bit set, any user with write and execute permissions for the directory can rename or delete contained files, regardless of the file's owner. Typically this is set on the /tmp directory to prevent ordinary users from deleting or moving other users' files.
The modern function of the sticky bit refers to directories, and protects directories and their content from being hijacked by non-owners; this is found in most modern Unix-like systems. Files in a shared directory such as /tmp belong to individual owners, and non-owners may not delete, overwrite or rename them.
History
The sticky bit was introduced in the Fifth Edition of Unix (in 1974) for use with pure executable files. When set, it instructed the operating system to retain the text segment of the program in swap space after the process exited. This speeds up subsequent executions by allowing the kernel to make a single operation of moving the program from swap to real memory. Thus, frequently-used programs like editors would load noticeably faster. One notable problem with "stickied" programs was replacing the executable (for instance, during patching); to do so required removing the sticky bit from the executable, executing the program and exiting to flush the
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https://en.wikipedia.org/wiki/Rainbow%20100
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The Rainbow 100 is a microcomputer introduced by Digital Equipment Corporation (DEC) in 1982. This desktop unit had a monitor similar to the VT220 and a dual-CPU box with both Zilog Z80 and Intel 8088 CPUs.
The Rainbow 100 was a triple-use machine: VT100 mode (industry standard terminal for interacting with DEC's own VAX), 8-bit CP/M mode (using the Z80), and CP/M-86 or MS-DOS mode using the 8088.
It ultimately failed to in the marketplace which became dominated by the simpler IBM PC and its clones which established the industry standard as compatibility with CP/M became less important than IBM PC compatibility. Writer David Ahl called it a disastrous foray into the personal computer market.
The Rainbow was launched along with the similarly packaged DEC Professional and DECmate II which were also not successful. The failure of DEC to gain a significant foothold in the high-volume PC market would be the beginning of the end of the computer hardware industry in New England, as nearly all computer companies located there were focused on minicomputers for large organizations, from DEC to Data General, Wang, Prime, Computervision, Honeywell, and Symbolics Inc.
Models
The Rainbow came in three models, the 100A, 100B and 100+. The "A" model was the first released, followed later by the "B" model. The most noticeable differences between the two models were the firmware and slight hardware changes. The systems were referred to with model numbers PC-100A and PC-100B respectively; later were also designated PC-100B2. The system included a user-changeable ROM chip in a special casing to support their keyboard layout and language of the boot screen. On the 100A, the ROMs only supported three languages.
The Rainbow did not have an ISA bus, so the typical RAM limit didn't apply, with both models supporting a maximum RAM of over .
PC-100A
The "A" model was the first produced by Digital. The distinguishing characteristic of the "A" model from an end-user perspective wa
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https://en.wikipedia.org/wiki/Webcentral
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Webcentral, formerly known as Melbourne IT Group, is an Australian digital services provider. It is a publicly-traded company that was listed on the Australian Securities Exchange () in December 1999. It provides internet domain registration, email/office applications, cloud hosting, cloud services, 5G networks, managed services, IT services, DevOps security, and digital marketing. Founded in 1996, it was the first Australian domain name registrar.
History
Beginnings
Webcentral's history dates back to April 1996 when Eugene Falk and Professor Peter Gerrand were appointed as Chairman and CEO, respectively, for the University of Melbourne's new commercial subsidiary Melbourne Information Technology International, which commenced operations from 1 May 1996. Professor Iain Morrison was appointed the third foundation director of the company. The company chose to trade under the business name of Melbourne IT from its earliest days.
Contrary to popular belief, the company was not set up to trade in domain names. The company's charter was to demonstrate the University's strategic leadership in working with industry and government in selected areas of IT. Its first and continuingly profitable business, up until its float on the Australian Securities Exchange in December 1999, was its joint venture ASAC (Advanced Services Applications Centre) with Ericsson Australia. ASAC was set up to develop applications with synergies between the Internet and advanced telecommunications, particularly mobile products. ASAC was recognized by Ericsson as one of its Global Design Centres in 1997 and contributed $0.5 million in profit to Melbourne IT in the year before its float. ASAC was incorporated as an independent joint venture in December 2000, but became a casualty of Ericsson's downsizing of its global R&D following the bursting of the Dot-com bubble in July 2000.
On 21 June 1996 a front-page article in the Australian Financial Review (AFR) by Charles Wright drew attention to the p
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https://en.wikipedia.org/wiki/Information%20continuum
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The term information continuum is used to describe the whole set of all information, in connection with information management. The term may be used in reference to the information or the information infrastructure of a people, a species, a scientific subject or an institution.
Other usages
in biological anthropology, term information continuum is related to study of social information transfer and evolution of communication in animals.
the Internet is sometimes called an information continuum.
References
External links
Monash University - Faculty of Information Technology
Information theory
Information management
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https://en.wikipedia.org/wiki/Foundation%20species
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In ecology, the foundation species are species that have a strong role in structuring a community. A foundation species can occupy any trophic level in a food web (i.e., they can be primary producers, herbivores or predators). The term was coined by Paul K. Dayton in 1972, who applied it to certain members of marine invertebrate and algae communities. It was clear from studies in several locations that there were a small handful of species whose activities had a disproportionate effect on the rest of the marine community and they were therefore key to the resilience of the community. Dayton’s view was that focusing on foundation species would allow for a simplified approach to more rapidly understand how a community as a whole would react to disturbances, such as pollution, instead of attempting the extremely difficult task of tracking the responses of all community members simultaneously. The term has since been applied to a range of organisms in ecosystems around the world, in both aquatic and terrestrial environments. Aaron Ellison et al. introduced the term to terrestrial ecology by applying the term foundation species to tree species that define and structure certain forest ecosystems through their influences on associated organisms and modulation of ecosystem processes.
Examples and outcomes of foundation species loss
A study conducted at the McKenzie Flats of the Sevilleta National Wildlife Refuge in New Mexico, a semiarid biome transition zone, observed the result of loss of a variety of different dominant and codominant foundation species of plants on the growth of other species. This transition zone consists of two Chihuahuan Desert species, black grama (Bouteloua eriopoda) and creosote bush (Larrea tridentata), and a shortgrass steppe species, blue grama (Bouteloua gracillis). Each species dominates an area with a specific soil environment. Black grama dominates sandy soils, while blue grama dominates in soils with high clay content, and creosote bush
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https://en.wikipedia.org/wiki/Rock%20mechanics
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Rock mechanics is a theoretical and applied science of the mechanical behavior of rocks and rock masses.
Compared to geology, it is the branch of mechanics concerned with the response of rock and rock masses to the force fields of their physical environment.
Background
Rock mechanics is part of a much broader subject of geomechanics, which is concerned with the mechanical responses of all geological materials, including soils.
Rock mechanics is concerned with the application of the principles of engineering mechanics to the design of structures built in or on rock. The structure could include many objects such as a drilling well, a mine shaft, a tunnel, a reservoir dam, a repository component, or a building. Rock mechanics is used in many engineering disciplines, but is primarily used in Mining, Civil, Geotechnical, Transportation, and Petroleum Engineering.
Rock mechanics answers questions such as, "is reinforcement necessary for a rock, or will it be able to handle whatever load it is faced with?" It also includes the design of reinforcement systems, such as rock bolting patterns.
Assessing the Project Site
Before any work begins, the construction site must be investigated properly to inform of the geological conditions of the site. Field observations, deep drilling, and geophysical surveys, can all give necessary information to develop a safe construction plan and create a site geological model. The level of investigation conducted at this site depends on factors such as budget, time frame, and expected geological conditions.
The first step of the investigation is the collection of maps and aerial photos to analyze. This can provide information about potential sinkholes, landslides, erosion, etc. Maps can provide information on the rock type of the site, geological structure, and boundaries between bedrock units.
Boreholes
Creating a borehole is a technique that consists of drilling through the ground in various areas at various depths, to get a bett
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https://en.wikipedia.org/wiki/Biochemical%20cascade
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A biochemical cascade, also known as a signaling cascade or signaling pathway, is a series of chemical reactions that occur within a biological cell when initiated by a stimulus. This stimulus, known as a first messenger, acts on a receptor that is transduced to the cell interior through second messengers which amplify the signal and transfer it to effector molecules, causing the cell to respond to the initial stimulus. Most biochemical cascades are series of events, in which one event triggers the next, in a linear fashion. At each step of the signaling cascade, various controlling factors are involved to regulate cellular actions, in order to respond effectively to cues about their changing internal and external environments.
An example would be the coagulation cascade of secondary hemostasis which leads to fibrin formation, and thus, the initiation of blood coagulation. Another example, sonic hedgehog signaling pathway, is one of the key regulators of embryonic development and is present in all bilaterians. Signaling proteins give cells information to make the embryo develop properly. When the pathway malfunctions, it can result in diseases like basal cell carcinoma. Recent studies point to the role of hedgehog signaling in regulating adult stem cells involved in maintenance and regeneration of adult tissues. The pathway has also been implicated in the development of some cancers. Drugs that specifically target hedgehog signaling to fight diseases are being actively developed by a number of pharmaceutical companies.
Introduction
Signaling cascades
Cells require a full and functional cellular machinery to live. When they belong to complex multicellular organisms, they need to communicate among themselves and work for symbiosis in order to give life to the organism. These communications between cells triggers intracellular signaling cascades, termed signal transduction pathways, that regulate specific cellular functions. Each signal transduction occurs with a p
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https://en.wikipedia.org/wiki/Zero%20ring
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In ring theory, a branch of mathematics, the zero ring or trivial ring is the unique ring (up to isomorphism) consisting of one element. (Less commonly, the term "zero ring" is used to refer to any rng of square zero, i.e., a rng in which for all x and y. This article refers to the one-element ring.)
In the category of rings, the zero ring is the terminal object, whereas the ring of integers Z is the initial object.
Definition
The zero ring, denoted {0} or simply 0, consists of the one-element set {0} with the operations + and · defined such that 0 + 0 = 0 and 0 · 0 = 0.
Properties
The zero ring is the unique ring in which the additive identity 0 and multiplicative identity 1 coincide. (Proof: If in a ring R, then for all r in R, we have . The proof of the last equality is found here.)
The zero ring is commutative.
The element 0 in the zero ring is a unit, serving as its own multiplicative inverse.
The unit group of the zero ring is the trivial group {0}.
The element 0 in the zero ring is not a zero divisor.
The only ideal in the zero ring is the zero ideal {0}, which is also the unit ideal, equal to the whole ring. This ideal is neither maximal nor prime.
The zero ring is generally excluded from fields, while occasionally called as the trivial field. Excluding it agrees with the fact that its zero ideal is not maximal. (When mathematicians speak of the "field with one element", they are referring to a non-existent object, and their intention is to define the category that would be the category of schemes over this object if it existed.)
The zero ring is generally excluded from integral domains. Whether the zero ring is considered to be a domain at all is a matter of convention, but there are two advantages to considering it not to be a domain. First, this agrees with the definition that a domain is a ring in which 0 is the only zero divisor (in particular, 0 is required to be a zero divisor, which fails in the zero ring). Second, this way, for a
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https://en.wikipedia.org/wiki/Trumpet%20Winsock
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Trumpet Winsock is a TCP/IP stack for Windows 3.x that implemented the Winsock API, which is an API for network sockets. It was developed by Peter Tattam from Trumpet Software International and distributed as shareware software.
History
The first version, 1.0A, was released in 1994. It rapidly gained reputation as the best tool for connecting to the internet. Guides for internet connectivity commonly advised to use Trumpet Winsock. The author received very little financial compensation for developing the software. In 1996, a 32-bit version was released.
Lawsuit
In the Trumpet Software Pty Ltd. v OzEmail Pty Ltd. case, the defendant had distributed Trumpet Winsock for free with a magazine. It did also suppress notices that the software was developed by Trumpet Software.
Replacement by Microsoft
Windows 95 includes an IPv4 stack but it is not installed by default. An early version of this IPv4 stack, codenamed Wolverine, was released by Microsoft for Windows for Workgroups in 1994. Microsoft also released Internet Explorer 5 for Windows 3.x with an included dialer application for calling the modem pool of a dial-up Internet service provider. The Wolverine stack does not include a dialer but another computer on the same LAN may make a dialed connection or a dialer not included with Wolverine may be used on the computer using Wolverine.
Architecture
The binary for Trumpet Winsock is called TCPMAN.EXE. Other files included the main winsock.dll and three UCSC connection .cmd file scripts.
References
External links
Internet Archive - Trumpet Winsock
Winworld - Trumpet Winsock
Cyber Harvard - Using Trumpet On Netcruiser Accounts
Network socket
1994 software
History of the Internet
Windows communication and services
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https://en.wikipedia.org/wiki/Grapher
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Grapher is a computer program bundled with macOS since version 10.4 that is able to create 2D and 3D graphs from simple and complex equations. It includes a variety of samples ranging from differential equations to 3D-rendered Toroids and Lorenz attractors. It is also capable of dealing with functions and compositions of them. One can edit the appearance of graphs by changing line colors, adding patterns to rendered surfaces, adding comments, and changing the fonts and styles used to display them. Grapher is able to create animations of graphs by changing constants or rotating them in space.
History
Before Grapher and Mac OS X, Mac OS 9 was bundled with Pacific Tech's Graphing Calculator, a similar program to Grapher that had been included with over 20 million Macintoshes since 1994 with System 7. No versions of Mac OS X prior to Mac OS X v10.4 included a bundled graphing calculator application. On July 22, 2004, Apple bought Arizona Software's "Curvus Pro X," and renamed it “Graphing Calculator”, before deciding on “Grapher”. The news was publicly announced on September 15, 2004 at AppleInsider.
Version 2.0 of Grapher was bundled with Mac OS X v10.5, and version 2.1 with Mac OS X v10.6. It was notable for being one of the few applications bundled with 10.6 to ship without 64-bit support. As of OS X 10.9, it became a 64-bit application.
Features
Grapher is a graphing calculator capable of creating both 2D graphs including classic (linear-linear), polar coordinates, linear-logarithmic, log-log, and polar log, as well as 3D graphs including standard system, cylindrical system, and spherical system. Grapher is a Cocoa application which takes advantage of Mac OS X APIs. It also supports multiple equations in one graph, exporting equations to LaTeX format, and comes with several pre-made equation examples. It is one of the few sophisticated graphing programs available capable of easily exporting clean vector art for use in printed documents (although exporting 3D gr
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https://en.wikipedia.org/wiki/Residual%20stress
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In materials science and solid mechanics, residual stresses are stresses that remain in a solid material after the original cause of the stresses has been removed. Residual stress may be desirable or undesirable. For example, laser peening imparts deep beneficial compressive residual stresses into metal components such as turbine engine fan blades, and it is used in toughened glass to allow for large, thin, crack- and scratch-resistant glass displays on smartphones. However, unintended residual stress in a designed structure may cause it to fail prematurely.
Residual stresses can result from a variety of mechanisms including inelastic (plastic) deformations, temperature gradients (during thermal cycle) or structural changes (phase transformation). Heat from welding may cause localized expansion, which is taken up during welding by either the molten metal or the placement of parts being welded. When the finished weldment cools, some areas cool and contract more than others, leaving residual stresses. Another example occurs during semiconductor fabrication and microsystem fabrication when thin film materials with different thermal and crystalline properties are deposited sequentially under different process conditions. The stress variation through a stack of thin film materials can be very complex and can vary between compressive and tensile stresses from layer to layer.
Applications
While uncontrolled residual stresses are undesirable, some designs rely on them. In particular, brittle materials can be toughened by including compressive residual stress, as in the case for toughened glass and pre-stressed concrete. The predominant mechanism for failure in brittle materials is brittle fracture, which begins with initial crack formation. When an external tensile stress is applied to the material, the crack tips concentrate stress, increasing the local tensile stresses experienced at the crack tips to a greater extent than the average stress on the bulk material. This
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https://en.wikipedia.org/wiki/Assault%20pioneer
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An assault pioneer is an infantryman who is responsible for:
The construction of tools for infantry soldiers to cross natural and man-made obstacles as well as breaching of enemy fortifications
Supervising the construction of field defensive works such as bunkers, support weapon firing positions, etc.
The use of demolitions, land mines and booby traps, as well as their clearance
Performing of all other normal infantry duties as the situation requires
Assault pioneers are lineal descendants of pioneers who have formed an essential part of armies since at least the time of the Roman legions. These pioneers were normally employed to march in front of the advancing army, clearing the route as necessary. They could also construct defenses and bivouac facilities. More recently (since the Second World War) assault pioneers have normally formed a platoon in infantry battalions, and such platoons can be found in a number of British Army and Commonwealth infantry units. In some of these armies, soldiers serving in an assault pioneer platoon can be identified by a specialist skill badge of two crossed felling axes sewn on their uniforms. These felling axes have traditionally been iconic of the pioneer in various armies throughout history.
The wearing of beards by assault pioneers has also been a traditional practice at various times in infantry battalions of British and Commonwealth armies, such as those of Australia and Canada. This tradition began in the French Army (possibly in Napoleonic times) and was one of the dress practices adopted by the British after their defeat of Napoleon in 1815 (along with the Foot Guards bearskin headdress). In the Australian and Canadian armies, on special occasions some battalions may still parade a ceremonial detachment of assault pioneers in historical uniforms wearing leather aprons, gauntlets and gaiters, and carrying the various tools of their trade such as felling axes, crosscut saws, hatchets and billhooks, picks and shovels.
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https://en.wikipedia.org/wiki/Barbara%20Keeley
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Barbara Mary Keeley (born 26 March 1952) is a British Labour Party politician who has served as the Member of Parliament (MP) for Worsley and Eccles South, previously Worsley, since 2005. A member of the Labour Party, she has served as Shadow Minister for Music and Tourism since 2023. She previously served as Deputy Leader of the House of Commons from 2009 to 2010 and served in Jeremy Corbyn’s Shadow Cabinet as Shadow Minister for Mental Health and Social Care from 2016 to 2020.
Early life
Keeley was educated at Mount St Mary's College in Leeds and the University of Salford, gaining a BA in Politics and Contemporary History.
Her early career was with IBM, first as a Systems Engineer and then as a Field Systems Engineering Manager. Later she became an independent consultant, working on community regeneration issues across North West England.
She was elected as a Labour councillor on Trafford Council in 1995 on which Keeley served as a member for Priory ward until 2004. She was Cabinet member for Children and Young People, Early Years and Childcare and Health and Wellbeing. From 2002 to 2004, she was Cabinet member for Education, Children's Social Services and all services for children and young people and Director of a Pathfinder Children's Trust. She is a member of the GMB Union, the Co-operative Party and the Fabian Society.
From 2002 to 2005, she worked as a consultant to the charity, the Princess Royal Trust for Carers, researching carers' issues — particularly those related to primary health care. She is co-author of the reports Carers Speak Out and Primary Carers.
Parliamentary career
In the House of Commons, Keeley served as a member of the Constitutional Affairs Select committee and from February 2006, the Finance and Services Committee. On 8 February 2006, she was appointed as Parliamentary Private Secretary (PPS) to the Cabinet Office, working with the Cabinet Office Minister, Jim Murphy MP. In June 2006, she moved to be PPS to Jim Murphy as Minister o
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https://en.wikipedia.org/wiki/N%C3%A9ron%E2%80%93Severi%20group
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In algebraic geometry, the Néron–Severi group of a variety is
the group of divisors modulo algebraic equivalence; in other words it is the group of components of the Picard scheme of a variety. Its rank is called the Picard number. It is named after Francesco Severi and André Néron.
Definition
In the cases of most importance to classical algebraic geometry, for a complete variety V that is non-singular, the connected component of the Picard scheme is an abelian variety written
Pic0(V).
The quotient
Pic(V)/Pic0(V)
is an abelian group NS(V), called the Néron–Severi group of V. This is a finitely-generated abelian group by the Néron–Severi theorem, which was proved by Severi over the complex numbers and by Néron over more general fields.
In other words, the Picard group fits into an exact sequence
The fact that the rank is finite is Francesco Severi's theorem of the base; the rank is the Picard number of V, often denoted ρ(V). The elements of finite order are called Severi divisors, and form a finite group which is a birational invariant and whose order is called the Severi number. Geometrically NS(V) describes the algebraic equivalence classes of divisors on V; that is, using a stronger, non-linear equivalence relation in place of linear equivalence of divisors, the classification becomes amenable to discrete invariants. Algebraic equivalence is closely related to numerical equivalence, an essentially topological classification by intersection numbers.
First Chern class and integral valued 2-cocycles
The exponential sheaf sequence
gives rise to a long exact sequence featuring
The first arrow is the first Chern class on the Picard group
and the Neron-Severi group can be identified with its image.
Equivalently, by exactness, the Neron-Severi group is the kernel of the second arrow
In the complex case, the Neron-Severi group is therefore the group of 2-cocycles whose Poincaré dual is represented by a complex hypersurface, that is, a Weil divisor.
For
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https://en.wikipedia.org/wiki/Virotherapy
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Virotherapy is a treatment using biotechnology to convert viruses into therapeutic agents by reprogramming viruses to treat diseases. There are three main branches of virotherapy: anti-cancer oncolytic viruses, viral vectors for gene therapy and viral immunotherapy. These branches use three different types of treatment methods: gene overexpression, gene knockout, and suicide gene delivery. Gene overexpression adds genetic sequences that compensate for low to zero levels of needed gene expression. Gene knockout uses RNA methods to silence or reduce expression of disease-causing genes. Suicide gene delivery introduces genetic sequences that induce an apoptotic response in cells, usually to kill cancerous growths. In a slightly different context, virotherapy can also refer more broadly to the use of viruses to treat certain medical conditions by killing pathogens.
History
Chester M. Southam, a researcher at Memorial Sloan Kettering Cancer Center, pioneered the study of viruses as potential agents to treat cancer.
Oncolytic virotherapy
Oncolytic virotherapy is not a new idea – as early as the mid 1950s doctors were noticing that cancer patients who suffered a non-related viral infection, or who had been vaccinated recently, showed signs of improvement; this has been largely attributed to the production of interferon and tumour necrosis factors in response to viral infection, but oncolytic viruses are being designed that selectively target and lyse only cancerous cells.
In the 1940s and 1950s, studies were conducted in animal models to evaluate the use of viruses in the treatment of tumours. In the 1940s–1950s some of the earliest human clinical trials with oncolytic viruses were started.
Mechanism
It is believed that oncolytic virus achieve their goals by two mechanisms: selective killing of tumor cells as well as recruitment of host immune system. One of the major challenges in cancer treatment is finding treatments that target tumor cells while ignoring non-canc
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