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https://en.wikipedia.org/wiki/SETAR%20%28model%29
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In statistics, Self-Exciting Threshold AutoRegressive (SETAR) models are typically applied to time series data as an extension of autoregressive models, in order to allow for higher degree of flexibility in model parameters through a regime switching behaviour.
Given a time series of data xt, the SETAR model is a tool for understanding and, perhaps, predicting future values in this series, assuming that the behaviour of the series changes once the series enters a different regime. The switch from one regime to another depends on the past values of the x series (hence the Self-Exciting portion of the name).
The model consists of k autoregressive (AR) parts, each for a different regime. The model is usually referred to as the SETAR(k, p) model where k is the number of threshold, there are k+1 number of regime in the model, and p is the order of the autoregressive part (since those can differ between regimes, the p portion is sometimes dropped and models are denoted simply as SETAR(k).
Definition
Autoregressive Models
Consider a simple AR(p) model for a time series yt
where:
for i=1,2,...,p are autoregressive coefficients, assumed to be constant over time;
stands for white-noise error term with constant variance.
written in a following vector form:
where:
is a row vector of variables;
is the vector of parameters :;
stands for white-noise error term with constant variance.
SETAR as an Extension of the Autoregressive Model
SETAR models were introduced by Howell Tong in 1977 and more fully developed in the seminal paper (Tong and Lim, 1980). They can be thought of in terms of extension of autoregressive models, allowing for changes in the model parameters according to the value of weakly exogenous threshold variable zt, assumed to be past values of y, e.g. yt-d, where d is the delay parameter, triggering the changes.
Defined in this way, SETAR model can be presented as follows:
if
where:
is a column vector of variables;
are k+1 non-trivial threshold
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https://en.wikipedia.org/wiki/Backhaul%20%28telecommunications%29
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In a hierarchical telecommunications network, the backhaul portion of the network comprises the intermediate links between the core network, or backbone network, and the small subnetworks at the edge of the network.
The most common network type in which backhaul is implemented is a mobile network. A backhaul of a mobile network, also referred to as mobile-backhaul connects a cell site towards the core network. The two main methods of mobile backhaul implementations are fiber-based backhaul and wireless point-to-point backhaul. Other methods, such as copper-based wireline, satellite communications and point-to-multipoint wireless technologies are being phased out as capacity and latency requirements become higher in 4G and 5G networks.
In both the technical and commercial definitions, backhaul generally refers to the side of the network that communicates with the global Internet, paid for at wholesale commercial access rates to or at an Internet exchange point or other core network access location. Sometimes middle mile networks exist between the customer's own LAN and those exchanges. This can be a local WAN connection.
Cell phones communicating with a single cell tower constitute a local subnetwork; the connection between the cell tower and the rest of the world begins with a backhaul link to the core of the internet service provider's network (via a point of presence). A backhaul may include wired, fiber optic and wireless components. Wireless sections may include using microwave bands and mesh and edge network topologies that may use a high-capacity wireless channel to get packets to the microwave or fiber links.
Definition
Visualizing the entire hierarchical network as a human skeleton, the core network would represent the spine, the backhaul links would be the limbs, the edge networks would be the hands and feet, and the individual links within those edge networks would be the fingers and toes.
Other examples include:
Connecting wireless base stations
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https://en.wikipedia.org/wiki/Glue%20code
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In computer programming, glue code is executable code (often source code) that serves solely to "adapt" different parts of code that would otherwise be incompatible. Glue code does not contribute any functionality towards meeting program requirements. Instead, it often appears in code that lets existing libraries or programs interoperate, as in language bindings or foreign function interfaces such as the Java Native Interface, when mapping objects to a database using object-relational mapping, or when integrating two or more commercial off-the-shelf programs. Glue code may be written in the same language as the code it is gluing together, or in a separate glue language. Glue code is very efficient in rapid prototyping environments, where several components are quickly put together into a single language or framework.
Consequences
Because each component is independent (i.e. it is unaware of its relations and is only connected to another component through glue code), the behavior of a component and its interactions can change during the execution of the script. In addition, a different version of one of the components may behave differently, breaking the glue code.
High-level programming languages can suffer from performance penalties because glue code must run through the language interpreter, even when connecting high-performance subsystems. If performance is crucial, using configuration scripting is often preferred to directly connecting binary interfaces of components. In object-oriented scripting languages, glue code often eliminates the need for class hierarchies and large numbers of classes.
See also
Adapter pattern
Scripting language
Shell script
SWIG
Lua (programming language)
Glue logic
WinGlue
Wrapper function
Wrapper library
Method stub
References
Computer programming
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https://en.wikipedia.org/wiki/Symbiotic%20bacteria
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Symbiotic bacteria are bacteria living in symbiosis with another organism or each other. For example, rhizobia living in root nodules of legumes provide nitrogen fixing activity for these plants.
Types of symbiosis
Types of symbiotic relationships are mutualism, commensalism, parasitism, and amensalism.
Endosymbiosis
Endosymbionts live inside other organisms whether that be in their bodies or cells. The theory of endosymbiosis, as known as symbiogenesis, provides an explanation for the evolution of eukaryotic organisms. According to the theory of endosymbiosis for the origin of eukaryotic cells, scientists believe that eukaryotes originated from the relationship between two or more prokaryotic cells approximately 2.7 billion years ago. It is suggested that specifically ancestors of mitochondria and chloroplasts entered into an endosymbiotic relationship with another prokaryotic cell, eventually evolving into the eukaryotic cells that people are familiar with today.
Ectosymbiosis
Ectosymbiosis is defined as a symbiotic relationship in which one organism lives on the outside surface of a different organism. For instance, barnacles on whales is an example of an ectosymbiotic relationship where the whale provides the barnacle with a home, a ride, and access to food. The whale is not harmed, but it also does not receive any benefits so this is also an example of commensalism. An example of ectosymbiotic bacteria is cutibacterium acnes. These bacteria are involved in a symbiotic relationship with humans on whose skin they live. Cutibacterium acnes can cause acne when the skin becomes too oily, but they also reduce the skin's susceptibility to skin diseases caused by oxidative stress.
Symbiotic relationships
Certain plants establish a symbiotic relationship with bacteria, enabling them to produce nodules that facilitate the conversion of atmospheric nitrogen to ammonia. In this connection, cytokinins have been found to play a role in the development of root fixing n
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https://en.wikipedia.org/wiki/Derived%20unique%20key%20per%20transaction
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In cryptography, Derived Unique Key Per Transaction (DUKPT) is a key management scheme in which for every transaction, a unique key is used which is derived from a fixed key. Therefore, if a derived key is compromised, future and past transaction data are still protected since the next or prior keys cannot be determined easily. DUKPT is specified in ANSI X9.24 part 1.
Overview
DUKPT allows the processing of the encryption to be moved away from the devices that hold the shared secret. The encryption is done with a derived key, which is not re-used after the transaction. DUKPT is used to encrypt electronic commerce transactions. While it can be used to protect information between two companies or banks, it is typically used to encrypt PIN information acquired by Point-Of-Sale (POS) devices.
DUKPT is not itself an encryption standard; rather it is a key management technique. The features of the DUKPT scheme are:
enable both originating and receiving parties to be in agreement as to the key being used for a given transaction,
each transaction will have a distinct key from all other transactions, except by coincidence,
if a present derived key is compromised, past and future keys (and thus the transactional data encrypted under them) remain uncompromised,
each device generates a different key sequence,
originators and receivers of encrypted messages do not have to perform an interactive key-agreement protocol beforehand.
History
DUKPT was invented in the late 1980s at Visa but didn’t receive much acceptance until the 1990s, when industry practices shifted towards recommending, and later requiring, that each device have a distinct encryption key.
Before DUKPT, state of the art was known as Master/Session, which required every PIN-encrypting device to be initialized with a unique master key. In handling transactions originating from devices using Master/Session key management, an unwanted side effect was the need for a table of encryption keys as numerous
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https://en.wikipedia.org/wiki/Srm%20%28Unix%29
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srm (or Secure Remove) is a command line utility for Unix-like computer systems for secure file deletion. srm removes each specified file by overwriting, renaming, and truncating it before unlinking. This prevents other people from undeleting or recovering any information about the file from the command line.
Platform-specific behaviours and bugs
Filesystems with hard links
Attempting to secure delete a file with multiple hard links results in a warning from srm stating that the current access path has been unlinked, but the data itself was not overwritten or truncated. This is an undocumented feature of srm 1.2.8 on Mac OS X 10.9, and is erroneously documented in 1.2.11 as a behaviour activated by the OpenBSD rm-compatible option -P. However, in both the OS X and SourceForge srm implementations, the behaviour of unlinking but not overwriting multi-linked files is always active, as long as the platform reports hard links.
srm 1.2.8 on Mac OS X 10.9 has a -n option, which means "overwrite file, but do not rename or unlink it." However, if the file has multiple links, the multiple-link file data protection feature activates first, removing the file, even though the -n option specifies "do not rename or unlink the file". The -n option has been removed from the code and manual of srm version 1.2.11, the latest SourceForge.net version. As a consequence, this option/feature conflict does not occur.
OS X
A number of file systems support file forks (called resource forks and named forks on OS X (particularly HFS+), and alternate data streams on NTFS), or extended attributes. However, OS X is the only platform on which srm securely deletes any of this additional data in files.
On OS X, only the most common non-data fork, the resource fork, is handled in this way. This support was included in Apple’s 1.2.8 and SourceForge's 1.2.9.
srm was removed from OS X/macOS in v10.11 El Capitan, as part of the removal of the "Secure Empty Trash" feature for security reasons.
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https://en.wikipedia.org/wiki/Calix%2C%20Inc.
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Calix, Inc. is a telecommunications company that specializes in providing software platforms, systems, and services to support the delivery of broadband services. The company was founded in 1999 and is headquartered in San Jose, California.
Calix provides cloud, software platforms, systems and services to communications service providers.
Calix maintains facilities in Petaluma, CA, Minneapolis, MN, San Jose, CA, Richardson, TX in the USA and facilities in Nanjing, China and Bangalore, India..
Customers
Calix customers include SCTelcom, Verizon, ALLO Communications, CityFibre, Nex-Tech, Gibson Connect, ITS Fiber, Sogetel, and over 1,600 other broadband service providers globally, majority being in North America.
Competitors
Calix competitors include Cisco, Adtran, Nokia, Allied Telesis, Huawei, Tellabs, ZTE and DZS.
Industry News
With Amazon Alexa, Calix Translates Smart Home Opp Into Reality
Amazon expands white-box Alexa device lineup with new home hub and gateway hardware
How Verizon & Calix Unlocked NGPON2
Acquisitions history
In 2006, Calix purchased Optical Solutions, Inc., based in Minneapolis, MN.
In 2010, Calix announced acquisition of one-time rival Occam Networks, Inc., based in Santa Barbara, California. The acquisition was completed in February, 2011.
In Nov 2012, Calix completed acquisition of Ericsson’s fiber access assets.
Other Resources
References
External links
Companies listed on the New York Stock Exchange
Companies based in Sonoma County, California
Telecommunications companies established in 1999
Telecommunications companies of the United States
Networking companies of the United States
Networking hardware companies
1999 establishments in California
Computer companies of the United States
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https://en.wikipedia.org/wiki/Artificial%20cell
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An artificial cell, synthetic cell or minimal cell is an engineered particle that mimics one or many functions of a biological cell. Often, artificial cells are biological or polymeric membranes which enclose biologically active materials. As such, liposomes, polymersomes, nanoparticles, microcapsules and a number of other particles can qualify as artificial cells.
The terms "artificial cell" and "synthetic cell" are used in a variety of different fields and can have different meanings, as it is also reflected in the different sections of this article. Some stricter definitions are based on the assumption that the term "cell" directly relates to biological cells and that these structures therefore have to be alive (or part of a living organism) and, further, that the term "artificial" implies that these structures are artificially built from the bottom-up, i.e. from basic components. As such, in the area of synthetic biology, an artificial cell can be understood as a completely synthetically made cell that can capture energy, maintain ion gradients, contain macromolecules as well as store information and have the ability to replicate. This kind of artificial cell has not yet been made.
However, in other cases, the term "artificial" does not imply that the entire structure is man-made, but instead, it can refer to the idea that certain functions or structures of biological cells can be modified, simplified, replaced or supplemented with a synthetic entity.
In other fields, the term "artificial cell" can refer to any compartment that somewhat resembles a biological cell in size or structure, but is synthetically made, or even fully made from non-biological components. The term "artificial cell" is also used for structures with direct applications such as compartments for drug delivery. Micro-encapsulation allows for metabolism within the membrane, exchange of small molecules and prevention of passage of large substances across it. The main advantages of encapsulati
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https://en.wikipedia.org/wiki/Postal%20Alpha%20Numeric%20Encoding%20Technique
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The Postal Alpha Numeric Encoding Technique (PLANET) barcode was used by the United States Postal Service to identify and track pieces of mail during delivery - the Post Office's "CONFIRM" services. It was fully superseded by Intelligent Mail Barcode by January 28, 2013.
Barcode
A PLANET barcode appears either 12 or 14 digits long. The barcode:
identifies mailpiece class and shape
identifies the Confirm Subscriber ID
includes up to 6 digits of additional information that the Confirm subscriber chose, such as a mailing number, mailing campaign ID or customer ID
ends with a check digit
Encoding
Like POSTNET, PLANET encodes the data in half- and full-height bars. Also like POSTNET, PLANET always starts and ends with a full bar (often called a guard rail), and each individual digit is represented by a set of five bars using a two-out-of-five code. However, in POSTNET, the two bars are full bars; in PLANET, the two-of-five are the short bars. As with POSTNET, the check digit is calculated by summing the other characters and calculating the single digit which, when added to the sum, makes the total divisible by 10.
References
External links
http://www.usps.com/strategicplanning/cs05/chp2_021.html
http://www.bccsoftware.com/currentevents/articles/articles/bcc_wwm_article.asp
Barcodes
United States Postal Service
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https://en.wikipedia.org/wiki/Perplexity
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In information theory, perplexity is a measurement of how well a probability distribution or probability model predicts a sample. It may be used to compare probability models. A low perplexity indicates the probability distribution is good at predicting the sample. Perplexity was originally introduced in 1977 in the context of speech recognition by Frederick Jelinek, Robert Leroy Mercer, Lalit R. Bahl, and James K. Baker.
Perplexity of a Probability Distribution
The perplexity PP of a discrete probability distribution p is a concept widely used in information theory, machine learning, and statistical modeling. It is defined as
where H(p) is the entropy (in bits) of the distribution, and x ranges over the events. The base of the logarithm need not be 2: The perplexity is independent of the base, provided that the entropy and the exponentiation use the same base. In some contexts, this measure is also referred to as the (order-1 true) diversity.
Perplexity of a random variable X may be defined as the perplexity of the distribution over its possible values x. It can be thought of as a measure of uncertainty or "surprise" related to the outcomes.
In the special case where p models a fair k-sided die (a uniform distribution over k discrete events), its perplexity is k. A random variable with perplexity k has the same uncertainty as a fair k-sided die. One is said to be "k-ways perplexed" about the value of the random variable. Unless it is a fair k-sided die, more than k values may be possible, but the overall uncertainty is not greater because some values may have a probability greater than 1/k.
Perplexity is sometimes used as a measure of the difficulty of a prediction problem. However, it's not always an accurate representation. For example, if you have two choices, one with probability 0.9, your chances of a correct guess using the optimal strategy are 90 percent. Yet, the perplexity is 2−0.9 log2 0.9 - 0.1 log2 0.1= 1.38. The inverse of the perplexity, 1/1.38
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https://en.wikipedia.org/wiki/Multitape%20Turing%20machine
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A multi-tape Turing machine is a variant of the Turing machine that utilizes several tapes. Each tape has its own head for reading and writing. Initially, the input appears on tape 1, and the others start out blank.
This model intuitively seems much more powerful than the single-tape model, but any multi-tape machine—no matter how many tapes—can be simulated by a single-tape machine using only quadratically more computation time. Thus, multi-tape machines cannot calculate any more functions than single-tape machines, and none of the robust complexity classes (such as polynomial time) are affected by a change between single-tape and multi-tape machines.
Formal definition
-tape Turing machine can be formally defined as a 7-tuple , following the notation of a Turing machine:
is a finite, non-empty set of tape alphabet symbols;
is the blank symbol (the only symbol allowed to occur on the tape infinitely often at any step during the computation);
is the set of input symbols, that is, the set of symbols allowed to appear in the initial tape contents;
is a finite, non-empty set of states;
is the initial state;
is the set of final states or accepting states. The initial tape contents is said to be accepted by if it eventually halts in a state from .
is a partial function called the transition function, where L is left shift, R is right shift.
A -tape Turing machine computes as follows. Initially, receives its input on the leftmost positions of the first tape, the rest of the first tape as well as other tapes is blank (i.e., filled with blank symbols). All the heads start on the leftmost position of the tapes. Once has started, the computation proceeds according to the rules described by the transition function. The computation continues until it enters the accept states, at which point it halts.
Two-stack Turing machine
Two-stack Turing machines have a read-only input and two storage tapes. If a head moves left on either tape a blank is printed on
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https://en.wikipedia.org/wiki/Wireless%20Toronto
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Wireless Toronto is a volunteer not-for-profit community wireless network in Toronto. Wireless Toronto began in 2005 with the goal of setting up no-cost public wireless Internet access around the Greater Toronto Area and exploring ways to use Wi-Fi technology to strengthen local community and culture. At its peak, Wireless Toronto hotspots served over 1000 connections per day at 38 individual locations.
Wireless Toronto hotspots are created using Linksys WRT54G or Motorola WR850G wireless routers running OpenWrt and WifiDog.
Other free wireless services in the GTA
The Toronto Public Library (TPL) offers free public wireless access in all of its 99 branches.
The Markham Public Libraries (MPL) offers free public wireless access in the Angus Glen Library, the Markham Village Library, the Thornhill Community Library, and the Unionville Library
Viva offers free wireless access on its Rapid Transit Vehicles
TOwifi offers a free Wi-Fi hotspot map
The TTC offers free, ad supported wireless service at many of its stations
See also
Municipal wireless network
List of wireless community networks by region
References
External links
Wireless Toronto Site
Wireless Toronto Blog
Wireless Toronto Locations Map
Toronto Public Library Free Wireless Internet Access Service
Toronto
Organizations based in Toronto
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https://en.wikipedia.org/wiki/Bombieri%E2%80%93Vinogradov%20theorem
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In mathematics, the Bombieri–Vinogradov theorem (sometimes simply called Bombieri's theorem) is a major result of analytic number theory, obtained in the mid-1960s, concerning the distribution of primes in arithmetic progressions, averaged over a range of moduli. The first result of this kind was obtained by Mark Barban in 1961 and the Bombieri–Vinogradov theorem is a refinement of Barban's result. The Bombieri–Vinogradov theorem is named after Enrico Bombieri and A. I. Vinogradov, who published on a related topic, the density hypothesis, in 1965.
This result is a major application of the large sieve method, which developed rapidly in the early 1960s, from its beginnings in work of Yuri Linnik two decades earlier. Besides Bombieri, Klaus Roth was working in this area. In the late 1960s and early 1970s, many of the key ingredients and estimates were simplified by Patrick X. Gallagher.
Statement of the Bombieri–Vinogradov theorem
Let and be any two positive real numbers with
Then
Here is the Euler totient function, which is the number of summands for the modulus q, and
where denotes the von Mangoldt function.
A verbal description of this result is that it addresses the error term in the prime number theorem for arithmetic progressions, averaged over the moduli q up to Q. For a certain range of Q, which are around if we neglect logarithmic factors, the error averaged is nearly as small as . This is not obvious, and without the averaging is about of the strength of the Generalized Riemann Hypothesis (GRH).
See also
Elliott–Halberstam conjecture (a generalization of Bombieri–Vinogradov)
Vinogradov's theorem (named after Ivan Matveyevich Vinogradov)
Notes
External links
The Bombieri-Vinogradov Theorem, R.C. Vaughan's Lecture note.
Sieve theory
Theorems in analytic number theory
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https://en.wikipedia.org/wiki/Guard%20byte
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A guard byte is a part of a computer program's memory that helps software developers find buffer overflows while developing the program.
Principle
When a program is compiled for debugging, all memory allocations are prefixed and postfixed by guard bytes. Special memory allocation routines may then perform additional tasks to determine unwanted read and write attempts outside the allocated memory. These extra bytes help to detect that the program is writing into (or even reading from) inappropriate memory areas, potentially causing buffer overflows. In case of accessing these bytes by the program's algorithm, the programmer is warned with information assisting him/her to locate the problem.
Checking for the inappropriate access to the guard bytes may be done in two ways:
by setting a memory breakpoint on a condition of write and/or read to those bytes, or
by pre-initializing the guard bytes with specific values and checking the values upon deallocation.
The first way is possible only with a debugger that handles such breakpoints, but significantly increases the chance of locating the problem. The second way does not require any debuggers or special environments and can be done even on other computers, but the programmer is alerted about the overflow only upon the deallocation, which is sometimes quite late.
Because guard bytes require additional code to be executed and additional memory to be allocated, they are used only when the program is compiled for debugging. When compiled as a release, guard bytes are not used at all, neither the routines working with them.
Example
A programmer wants to allocate a buffer of 100 bytes of memory while debugging. The system memory allocating routine will allocate 108 bytes instead, adding 4 leading and 4 trailing guard bytes, and return a pointer shifted by the 4 leading guard bytes to the right, hiding them from the programmer. The programmer should then work with the received pointer without the knowledge of the presence
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https://en.wikipedia.org/wiki/Ultra%20Port%20Architecture
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The Ultra Port Architecture (UPA) bus was developed by Sun Microsystems as a high-speed graphics card to CPU interconnect, beginning with the Ultra 1 workstation in 1995.
See also
List of device bandwidths
External links
UPA Bus Whitepaper
Computer buses
Sun Microsystems hardware
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https://en.wikipedia.org/wiki/Exec%20%28system%20call%29
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In computing, exec is a functionality of an operating system that runs an executable file in the context of an already existing process, replacing the previous executable. This act is also referred to as an overlay. It is especially important in Unix-like systems, although it exists elsewhere. As no new process is created, the process identifier (PID) does not change, but the machine code, data, heap, and stack of the process are replaced by those of the new program.
The exec call is available for many programming languages including compilable languages and some scripting languages. In OS command interpreters, the built-in command replaces the shell process with the specified program.
Nomenclature
Interfaces to exec and its implementations vary. Depending on programming language it may be accessible via one or more functions, and depending on operating system it may be represented with one or more actual system calls. For this reason exec is sometimes described as a collection of functions.
Standard names of such functions in C are , , , , , and (see below), but not "exec" itself. The Linux kernel has one corresponding system call named "execve", whereas all aforementioned functions are user-space wrappers around it.
Higher-level languages usually provide one call named .
Unix, POSIX, and other multitasking systems
C language prototypes
The POSIX standard declares exec functions in the header file, in the C language. The same functions are declared in for DOS (see below), OS/2, and Microsoft Windows.
int execl(char const *path, char const *arg0, ...);
int execle(char const *path, char const *arg0, ..., char const *envp[]);
int execlp(char const *file, char const *arg0, ...);
int execv(char const *path, char const *argv[]);
int execve(char const *path, char const *argv[], char const *envp[]);
int execvp(char const *file, char const *argv[]);
int fexecve(int fd, char *const argv[], char *const envp[]);
Some implementations provide these functions named w
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https://en.wikipedia.org/wiki/Pileus%20%28mycology%29
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The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp (fungal fruiting body) that supports a spore-bearing surface, the hymenium. The hymenium (hymenophore) may consist of lamellae, tubes, or teeth, on the underside of the pileus. A pileus is characteristic of agarics, boletes, some polypores, tooth fungi, and some ascomycetes.
Classification
Pilei can be formed in various shapes, and the shapes can change over the course of the developmental cycle of a fungus. The most familiar pileus shape is hemispherical or convex. Convex pilei often continue to expand as they mature until they become flat. Many well-known species have a convex pileus, including the button mushroom, various Amanita species and boletes.
Some, such as the parasol mushroom, have distinct bosses or umbos and are described as umbonate. An umbo is a knobby protrusion at the center of the cap. Some fungi, such as chanterelles have a funnel- or trumpet-shaped appearance. In these cases the pileus is termed infundibuliform.
See also
Lamella
Stipe
Notes
References
Arora, D: "Mushrooms Demystified", Ten Speed Press, 1986.
Fungal morphology and anatomy
Mycology
ja:キノコの部位#傘
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https://en.wikipedia.org/wiki/Rugged%20computer
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A rugged computer or ruggedized computer is a computer specifically designed to operate reliably in harsh usage environments and conditions, such as strong vibrations, extreme temperatures and wet or dusty conditions. They are designed from inception for the type of rough use typified by these conditions, not just in the external housing but in the internal components and cooling arrangements as well.
Typical environments for rugged laptops, tablet PCs and PDAs are public safety, field sales, field service, manufacturing, retail, healthcare, construction, transportation/distribution and the military. They are used in the agricultural industries, and by individuals for outdoor recreation activities.
Construction
Virtually all rugged computers share an underlying design philosophy of providing a controlled environment for the installed electronics. Rugged computers are engineered to operate in the face of multiple challenges including:
Shock and vibration
Temperature and humidity
Corrosion and abrasion
Minimal size, weight, and power (SWaP)
Acoustic noise reduction
Low pressure/altitude
Ingress protection
Electromagnetic interference
Optimizations on performance
Electronic components themselves may be selected for their ability to withstand higher and lower operating temperatures than typical commercial components. Design engineering decisions such as reduction of cabling, addition of liquid cooling and heat sinks, and rugged materials, are made to ensure performance in harsh environments.
Features include fully sealed keyboards to protect against intrusion by dust or liquids, and scratch-resistant screens that are readable in direct sunlight.
Rugged units have higher prices. However, one research study found that in environments where rugged computers are commonly used, total cost of ownership was 36% lower for rugged notebooks and 33% less for handhelds and PDAs, compared to conventional non-rugged versions. The lower overall cost is due to lower f
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https://en.wikipedia.org/wiki/Quinarian%20system
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The quinarian system was a method of zoological classification which was popular in the mid 19th century, especially among British naturalists. It was largely developed by the entomologist William Sharp Macleay in 1819. The system was further promoted in the works of Nicholas Aylward Vigors, William John Swainson and Johann Jakob Kaup. Swainson's work on ornithology gave wide publicity to the idea. The system had opponents even before the publication of Charles Darwin's On the Origin of Species (1859), which paved the way for evolutionary trees.
Classification approach
Quinarianism gets its name from the emphasis on the number five: it proposed that all taxa are divisible into five subgroups, and if fewer than five subgroups were known, quinarians believed that a missing subgroup remained to be found.
Presumably this arose as a chance observation of some accidental analogies between different groups, but it was erected into a guiding principle by the quinarians. It became increasingly elaborate, proposing that each group of five classes could be arranged in a circle, with those closer together having greater affinities. Typically they were depicted with relatively advanced groups at the top, and supposedly degenerate forms towards the bottom. Each circle could touch or overlap with adjacent circles; the equivalent overlapping of actual groups in nature was called osculation.
Another aspect of the system was the identification of analogies across groups:
Quinarianism was not widely popular outside the United Kingdom (some followers like William Hincks persisted in Canada); it became unfashionable by the 1840s, during which time more complex "maps" were made by Hugh Edwin Strickland and Alfred Russel Wallace. Strickland and others specifically rejected the use of relations of "analogy" in constructing natural classifications. These systems were eventually discarded in favour of principles of genuinely natural classification, namely based on evolutionary relations
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https://en.wikipedia.org/wiki/BitVault
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BitVault is a content-addressable distributed storage system, developed by Microsoft Research in China. BitVault uses peer-to-peer technology to distribute the tasks of storing and managing data. As such, there is no central authority responsible for management of the system. Rather, it is self-managing, provides high availability, reliability and scales up in a self-organizing manner, with low administrative overhead, which is almost constant irrespective of the size of the distributed overlay network.
BitVault system is best suited for reference data, which is large amount of data which changes very infrequently. Such data include archives of out-of-date data, as well as multimedia data like music and video, which, even though might be frequently used, changes very rarely.
Technology
Every participating peer node in BitVault architecture is a Smart Brick, which is a trimmed down PC with large disks. All Smart Bricks in a BitVault system are connected by a high-bandwidth, low latency network. A BitVault system can be easily scaled up – any computer can be configured to act as a Smart Brick by simply installing the BitVault software, and connecting it to the network, without any need for interrupting the already working nodes.
BitVault stores immutable data objects, i.e., objects which cannot be changed. The physical location of the objects is not fixed and can be on any of the bricks. Its location changes depending on its frequency of access; it can even be replicated at more than one brick. To get around this problem of changing locations, BitVault makes it accessible by means of a 160-bit key, which is unique for each object. The system dynamically references the location from which the object can be retrieved most efficiently, by using the key, and makes the object available. The unique key is generated from a hash of the data of the object, thus making the system content-addressable, as opposed to location-addressable. The hashes of the objects (key) are map
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https://en.wikipedia.org/wiki/Hypothetical%20protein
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In biochemistry, a hypothetical protein is a protein whose existence has been predicted, but for which there is a lack of experimental evidence that it is expressed in vivo. Sequencing of several genomes has resulted in numerous predicted open reading frames to which functions cannot be readily assigned. These proteins, either orphan or conserved hypothetical proteins, make up an estimated 20% to 40% of proteins encoded in each newly sequenced genome. The real evidences for the hypothetical protein functioning in the metabolism of the organism can be predicted by comparing its sequence or structure homology by considering the conserved domain analysis. Even when there is enough evidence that the product of the gene is expressed, by techniques such as microarray and mass spectrometry, it is difficult to assign a function to it given its lack of identity to protein sequences with annotated biochemical function. Nowadays, most protein sequences are inferred from computational analysis of genomic DNA sequence. Hypothetical proteins are created by gene prediction software during genome analysis. When the bioinformatic tool used for the gene identification finds a large open reading frame without a characterised homologue in the protein database, it returns "hypothetical protein" as an annotation remark.
The function of a hypothetical protein can be predicted by domain homology searches with various confidence levels. Conserved domains are available in the hypothetical proteins which need to be compared with the known family domains by which hypothetical protein could be classified into particular protein families even though they have not been in vivo investigated. The function of hypothetical protein could also be predicted by homology modelling, in which hypothetical protein has to align with known protein sequence whose three dimensional structure is known and by modelling method if structure predicted then the capability of hypothetical protein to function could b
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https://en.wikipedia.org/wiki/Admissible%20ordinal
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In set theory, an ordinal number α is an admissible ordinal if Lα is an admissible set (that is, a transitive model of Kripke–Platek set theory); in other words, α is admissible when α is a limit ordinal and Lα ⊧ Σ0-collection. The term was coined by Richard Platek in 1966.
The first two admissible ordinals are ω and (the least nonrecursive ordinal, also called the Church–Kleene ordinal). Any regular uncountable cardinal is an admissible ordinal.
By a theorem of Sacks, the countable admissible ordinals are exactly those constructed in a manner similar to the Church–Kleene ordinal, but for Turing machines with oracles. One sometimes writes for the -th ordinal that is either admissible or a limit of admissibles; an ordinal that is both is called recursively inaccessible. There exists a theory of large ordinals in this manner that is highly parallel to that of (small) large cardinals (one can define recursively Mahlo ordinals, for example). But all these ordinals are still countable. Therefore, admissible ordinals seem to be the recursive analogue of regular cardinal numbers.
Notice that α is an admissible ordinal if and only if α is a limit ordinal and there does not exist a γ < α for which there is a Σ1(Lα) mapping from γ onto α. is an admissible ordinal iff there is a standard model of KP whose set of ordinals is , in fact this may be take as the definition of admissibility. The th admissible ordinal is sometimes denoted by p.174 or .
The Friedman-Jensen-Sacks theorem states that countable is admissible iff there exists some such that is the least ordinal not recursive in .
See also
α-recursion theory
Large countable ordinals
Constructible universe
Regular cardinal
References
Ordinal numbers
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https://en.wikipedia.org/wiki/Advantage%20%28cryptography%29
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In cryptography, an adversary's advantage is a measure of how successfully it can attack a cryptographic algorithm, by distinguishing it from an idealized version of that type of algorithm. Note that in this context, the "adversary" is itself an algorithm and not a person. A cryptographic algorithm is considered secure if no adversary has a non-negligible advantage, subject to specified bounds on the adversary's computational resources (see concrete security). "Negligible" usually means "within O(2−p)" where p is a security parameter associated with the algorithm. For example, p might be the number of bits in a block cipher's key.
Description of concept
Let F be an oracle for the function being studied, and let G be an oracle for an idealized function of that type. The adversary A is a probabilistic algorithm, given F or G as input, and which outputs 1 or 0. A's job is to distinguish F from G, based on making queries to the oracle that it's given. We say:
Examples
Let F be a random instance of the DES block cipher. This cipher has 64-bit blocks and a 56-bit key. The key therefore selects one of a family of 256 permutations on the 264 possible 64-bit blocks. A "random DES instance" means our oracle F computes DES using some key K (which is unknown to the adversary) where K is selected from the 256 possible keys with equal probability.
We want to compare the DES instance with an idealized 64-bit block cipher, meaning a permutation selected at random from the (264)! possible permutations on 64-bit blocks. Call this randomly selected permutation G. Note from Stirling's approximation that (264)! is around , so even specifying which permutation is selected requires writing down a number too large to represent exactly in any real computer. Viewed another way, G is an instance of a "cipher" whose "key length" is about 1021 bits, which again is too large to fit in a computer. (We can, however, implement G with storage space proportional to the number of q
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https://en.wikipedia.org/wiki/Access%20Linux%20Platform
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The Access Linux Platform (ALP) is a discontinued open-source software based operating system, once referred to as a "next-generation version of the Palm OS," for mobile devices developed and marketed by Access Co., of Tokyo, Japan. The platform included execution environments for Java, classic Palm OS, and GTK+-based native Linux applications. ALP was demonstrated in devices at a variety of conferences, including 3GSM, LinuxWorld, GUADEC, and Open Source in Mobile.
The ALP was first announced in February 2006. The initial versions of the platform and software development kits were officially released in February 2007. There was a coordinated effort by Access, Esteemo, NEC, NTT DoCoMo, and Panasonic to use the platform as a basis for a shared platform implementing a revised version of the i.mode Mobile Oriented Applications Platform (MOAP) (L) application programming interfaces (APIs), conforming to the specifications of the LiMo Foundation. The first smartphone to use the ALP was to be the Edelweiss by Emblaze Mobile that was scheduled for mid-2009. However, it was shelved before release. The First Else (renamed from Monolith) smartphone, that was being developed by Sharp Corporation in cooperation with Emblaze Mobile and seven other partners, was scheduled for 2009, but was never released and officially cancelled in June 2010. The platform is no longer referenced on Access's website, but Panasonic and NEC released a number of ALP phones for the Japanese market between 2010 and 2013.
Look and feel
The user interface was designed with similar general goals to earlier Palm OS releases, with an aim of preserving the Zen of Palm, a design philosophy centered on making the applications as simple as possible. Other aspects of the interface included a task-based orientation rather than a file/document orientation as is commonly found on desktop systems.
The appearance of the platform was intended to be highly customizable to provide differentiation for specific device
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https://en.wikipedia.org/wiki/Coefficient%20matrix
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In linear algebra, a coefficient matrix is a matrix consisting of the coefficients of the variables in a set of linear equations. The matrix is used in solving systems of linear equations.
Coefficient matrix
In general, a system with linear equations and unknowns can be written as
where are the unknowns and the numbers are the coefficients of the system. The coefficient matrix is the matrix with the coefficient as the th entry:
Then the above set of equations can be expressed more succinctly as
where is the coefficient matrix and is the column vector of constant terms.
Relation of its properties to properties of the equation system
By the Rouché–Capelli theorem, the system of equations is inconsistent, meaning it has no solutions, if the rank of the augmented matrix (the coefficient matrix augmented with an additional column consisting of the vector ) is greater than the rank of the coefficient matrix. If, on the other hand, the ranks of these two matrices are equal, the system must have at least one solution. The solution is unique if and only if the rank equals the number of variables. Otherwise the general solution has free parameters; hence in such a case there are an infinitude of solutions, which can be found by imposing arbitrary values on of the variables and solving the resulting system for its unique solution; different choices of which variables to fix, and different fixed values of them, give different system solutions.
Dynamic equations
A first-order matrix difference equation with constant term can be written as
where is and and are . This system converges to its steady-state level of if and only if the absolute values of all eigenvalues of are less than 1.
A first-order matrix differential equation with constant term can be written as
This system is stable if and only if all eigenvalues of have negative real parts.
References
Linear algebra
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https://en.wikipedia.org/wiki/Matrix%20grammar
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A matrix grammar is a formal grammar in which instead of single productions, productions are grouped together into finite sequences. A production cannot be applied separately, it must be applied in sequence. In the application of such a sequence of productions, the rewriting is done in accordance to each production in sequence, the first one, second one etc. till the last production has been used for rewriting. The sequences are referred to as matrices.
Matrix grammar is an extension of context-free grammar, and one instance of a controlled grammar.
Formal definition
A matrix grammar is an ordered quadruple
where
is a finite set of non-terminals
is a finite set of terminals
is a special element of , viz. the starting symbol
is a finite set of non-empty sequences whose elements are ordered pairs where
The pairs are called productions, written as . The sequences are called matrices and can be written as
Let be the set of all productions appearing in the matrices of a matrix grammar . Then the matrix grammar is of type-, length-increasing, linear, -free, context-free or context-sensitive if and only if the grammar has the following property.
For a matrix grammar , a binary relation is defined; also represented as . For any , holds if and only if there exists an integer such that the words
over V exist and
and
is one of the matrices of
and for all such that
Let be the reflexive transitive closure of the relation . Then, the language generated by the matrix grammar is given by
Examples
Consider the matrix grammar
where is a collection containing the following matrices:
These matrices, which contain only context-free rules, generate the context-sensitive language
The associate word of
is
and
.
This example can be found on pages 8 and 9 of in the following form:
Consider the matrix grammar
where is a collection containing the following matrices:
These matrices, which contain only context-regular rules, generate the conte
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https://en.wikipedia.org/wiki/Elemental%20cost%20planning
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Elemental cost planning is a system of Cost planning and Cost control, typically for buildings, which enables the cost of a scheme to be monitored during design development.
1951 saw the publication of the Ministry of Education Building Bulletin No 4 which essentially introduced the concept of elemental cost planning to the UK construction industry. Its Author was James Nisbet. The concept has been refined and developed over more than 50 years in the UK by BCIS (the Building Cost Information Service of the Royal Institution of Chartered Surveyors)....
Elemental Cost Planning relies upon the adoption of a Standard Form of Cost Analysis for buildings which allows costs to be compared on a common format and forms the basis of the benchmarking analysis central to the concept of Elemental Cost Plans.
It should :-
Ensure that the tender amount is close to the first estimate, or that any likely difference between the two is anticipated and is acceptable.
Ensure that the money available for the projects is allocated consciously and economically to the various components and finishes.
Always involves the measurement and pricing of approximate quantities at some stage of the process.
Aim to achieve good value at the desired level of expenditure.
Elemental cost planning is often referred to as 'designing to a cost' or 'target cost planning' since a cost limit is fixed for the scheme and the architect must then prepare a design not to exceed this cost.
See also
Cost overrun
Comparative cost Analysis
BCIS
BCIS submits data exchange standard for UN ratification.
References
Cost planning of buildings - Douglas J Ferry (and others)
Cost studies of buildings 4th edn- Alan Ashworth
BCIS Standard Form of Cost Analysis (Analysis Forms)
BCIS Elemental Standard Form of Cost Analysis 4th edn
BCIS Principles of Elemental Classification for Buildings (International)
BCIS Proposed Standard form of Civil Engineering Cost Analysis
Business terms
Building engineering
Cost engineering
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https://en.wikipedia.org/wiki/Neugebauer%20equations
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The Neugebauer equations are a set of equations used to model color printing systems, developed by Hans E. J. Neugebauer. They were intended to predict the color produced by a combination of halftones printed in cyan, magenta, and yellow inks.
The equations estimate the reflectance (in CIE XYZ coordinates or as a function of wavelength) as a function of the reflectance of the 8 possible combinations of CMY inks (or the 16 combinations of CMYK inks), weighted by the area they take up on the paper. In wavelength form:
where Ri(λ) is the reflectance of ink combination i, and wi is the relative proportions of the 16 colors in a uniformly colored patch. The weights are dependent on the halftone pattern and possibly subject to various forms of dot gain.
Light can interact with the paper and ink in more complex ways. The Yule–Nielsen correction takes into account light entering through blank regions and re-emerging through ink:
The factor n would be 2 for a perfectly diffusing Lambertian paper substrate, but can be adjusted based on empirical measurements. Further considerations of the optics, such as multiple internal reflections, can be added at the price of additional complexity.
In order to achieve a desired reflectance, these equations have to be inverted to produce the actual dot areas or digital values sent to the printer, a nontrivial operation that may have multiple solutions.
See also
CMYK color model
References
Equations
Color
Printing
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https://en.wikipedia.org/wiki/2010%20Biodiversity%20Target
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The 2010 Biodiversity Target was an overall conservation target aiming to halt the decline of biodiversity by the end of 2010. The world largely failed to meet the target.
History of the 2010 Biodiversity Target
It was first adopted by EU Heads of State at the EU Summit in Gothenburg, Sweden, in June 2001. They decided that "biodiversity decline should be halted with the aim of reaching this objective by 2010".
One year later, the Convention on Biological Diversity's sixth Conference of the Parties adopted the Strategic Plan for the Convention in Decision VI/26. The Decision says "Parties commit themselves to a more effective and coherent implementation of the three objectives of the Convention, to achieve by 2010 a significant reduction of the current rate of biodiversity loss at the global, regional and national level as a contribution to poverty alleviation and to the benefit of all life on earth."
The World Summit on Sustainable Development held in Johannesburg in 2002 confirmed the 2010 Biodiversity Target and called for "the achievement by 2010 of a significant reduction in the current rate of loss of biological diversity".
In 2003, Environment Ministers and Heads of delegation from 51 countries in the United Nations Economic Commission for Europe (UNECE) region adopted the Kiev Resolution on Biodiversity at the fifth Ministerial Conference "Environment for Europe" and decided to "reinforce our objective to halt the loss of biological diversity at all levels by the year 2010".
By the year 2006, the following nations have contributed extensively to establishment of individual Biodiversity Action Plans: Tanzania, New Zealand, Great Britain and the United States of America, called Species Recovery Plans in the USA.
Progress at the European Level
The 2004 Irish Presidency held a major stakeholder conference on the 2010 Biodiversity Target which resulted in a detailed roadmap to 2010 called the "Message from Malahide". At the same time, a number of organisat
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https://en.wikipedia.org/wiki/Comparison%20of%20video%20hosting%20services
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The following tables compare general and technical information for a number of current, notable video hosting services. Please see the individual products' articles for further information.
General information
Basic general information about the hosts: creator/company, license/price etc.
Supported input file formats
All services support the following input file formats:
Moving Picture Experts Group (.MPG/MPEG-1)
QuickTime File Format (.MOV)
Windows Media Video (.WMV)
Audio Video Interleave (.AVI)
H.264 MPEG-4/AVC (.MP4)
Unless otherwise indicated, they also support the following input file formats:
Matroska Multimedia Container (.MKV)
Theora (.OGV)
3rd Generation Partnership Project (.3GP)
Streaming video technical information
Site traffic
Specifically dedicated video hosting websites
* Website predominantly hosts live streaming video.
See also
Comparison of streaming media software
Content delivery network
Streaming television
Internet Protocol television
Comparison of music streaming services
List of streaming media systems
List of online video platforms
Multicast
One-click hosting
P2PTV
Protection of Broadcasts and Broadcasting Organizations Treaty
Push technology
Streaming media
Video on demand
Webcast
References
Video services
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https://en.wikipedia.org/wiki/Clause%20%28logic%29
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In logic, a clause is a propositional formula formed from a finite collection of literals (atoms or their negations) and logical connectives. A clause is true either whenever at least one of the literals that form it is true (a disjunctive clause, the most common use of the term), or when all of the literals that form it are true (a conjunctive clause, a less common use of the term). That is, it is a finite disjunction or conjunction of literals, depending on the context. Clauses are usually written as follows, where the symbols are literals:
Empty clauses
A clause can be empty (defined from an empty set of literals). The empty clause is denoted by various symbols such as ,
, or . The truth evaluation of an empty disjunctive clause is always . This is justified by considering that is the neutral element of the monoid .
The truth evaluation of an empty conjunctive clause is always . This is related to the concept of a vacuous truth.
Implicative form
Every nonempty (disjunctive) clause is logically equivalent to an implication of a head from a body, where the head is an arbitrary literal of the clause and the body is the conjunction of the complements of the other literals. That is, if a truth assignment causes a clause to be true, and all of the literals of the body satisfy the clause, then the head must also be true.
This equivalence is commonly used in logic programming, where clauses are usually written as an implication in this form. More generally, the head may be a disjunction of literals. If are the literals in the body of a clause and are those of its head, the clause is usually written as follows:
If n = 1 and m = 0, the clause is called a (Prolog) fact.
If n = 1 and m > 0, the clause is called a (Prolog) rule.
If n = 0 and m > 0, the clause is called a (Prolog) query.
If n > 1, the clause is no longer Horn.
See also
Conjunctive normal form
Disjunctive normal form
Horn clause
References
External links
Clause logic related terminology
Pr
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https://en.wikipedia.org/wiki/International%20Movement%20Writing%20Alphabet
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The International Movement Writing Alphabet (IMWA) is a set of symbols that can be used to describe and record movement. Its creator, Valerie Sutton, also invented MovementWriting, a writing system which employs IMWA. It in turn has several application areas within which it is specialised.
Application areas
Sign language transcription
Sutton SignWriting is optimised for sign languages and has the most development so far.
Dance notation
DanceWriting is a form of dance notation.
Mimestry notation
MimeWriting is for classic mimestry.
Kinesiology
SportsWriting is for the kinesiology of ice skating and gymnastics.
Identification numbers
The IMWA has more than 27,000 elements that are represented by unique identification numbers. Each identification number specifies six attributes——as dash-separated values. The symbol is specified with a three-digit value whereas all other attributes use a two-digit value (e.g., 01-01-001-01-01-01).
There are eight categories: hand, movement, face, head, upper body, full body, space, and punctuation.
There are 40 groups. The are based on the 40 groups.
History
The IMWA was originally designed for describing sign language and consequently was named Sutton's Sign Symbol Sequence (SSS) by its inventor, Valerie Sutton. The original symbol set, SSS-95, was limited in size due to memory constraints in personal computers at the time. The SSS-99 symbol set expanded the number of symbols, and the SSS-2002 set was the first to use the current identification numbering system. The final version, SSS-2004, was renamed International Movement Writing Alphabet (SSS-IMWA) to reflect its usefulness in applications beyond sign language.
External links
MovementWriting
IMWA Design Documents
IMWA Keyboard Design
writing systems
constructed scripts
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https://en.wikipedia.org/wiki/Pipeflow
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In hydrology, pipeflow is a type of subterranean water flow where water travels along cracks in the soil or old root systems found in above ground vegetation.
In such soils which have a high vegetation content water is able to travel along the 'pipes', allowing water to travel faster than throughflow. Here, water can move at speeds between 50 and 500 m/h.
Hydrology
Aquatic ecology
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https://en.wikipedia.org/wiki/Herbert%20Booth
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Herbert Henry Howard Booth (26 August 1862 – 25 September 1926) was a Salvation Army officer, the third son of five children to William and Catherine Booth (Mumford), who later went on to serve as an independent evangelist. He oversaw the Limelight Department's development and he was the writer and director for Soldiers of the Cross.
Early life
Herbert, who was born in Penzance, Cornwall, received little formal elementary education but became a student at Allesly Park College and the Congregational Institute at Nottingham. At the age of twenty, Herbert began helping his sister Kate Booth in building up The Salvation Army in France. Two years later, he was given charge of England's cadet officer training. He wrote many songs for The Salvation Army and became a bandmaster and a songster leader. He was the first Salvation Army Officer to use the magic lantern for presentations in England.
In 1886, Herbert Booth took ill and went to Australia to rest and heal. While staying in a mining town there, he found a gold nugget. He eventually forged a ring out of it for his future wife, Dutch Salvationist Cornelie Schoch.
Salvation Army
Herbert Booth took command of all Salvation Army operations in the British Isles when he was 26. Then, from 1892–1896, he was the Commandant for the Salvation Army in Canada. Next, he was appointed to the Australasian Territory where his health continued to deteriorate. He struggled with depression, but was still very active in his position.
In Australia, Herbert took considerable interest in the Salvation Army's Limelight Department there. He soon authorized extensive expansion, allowing Limelight to make Australia's first fictional narrative film in 1897. The following year, he and early cinematographer Joe Perry produced Social Salvation, a multimedia presentation that portrayed the work of The Salvation Army in its Australasian Territory. Whilst appointed to the territory Herbert also founded the Hamodava Tea Company, which pion
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https://en.wikipedia.org/wiki/Frank%20Benford
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Frank Albert Benford Jr. (July 10, 1883 – December 4, 1948) was an American electrical engineer and physicist best known for rediscovering and generalizing Benford's Law, an earlier statistical statement by Simon Newcomb, about the occurrence of digits in lists of data.
Benford is also known for having devised, in 1937, an instrument for measuring the refractive index of glass. An expert in optical measurements, he published 109 papers in the fields of optics and mathematics and was granted 20 patents on optical devices.
Early life
He was born in Johnstown, Pennsylvania. His date of birth is given variously as May 29 or July 10, 1883. At the age of 6 his family home was destroyed by the Johnstown Flood.
Education
He graduated from the University of Michigan in 1910.
Career
Benford worked for General Electric, first in the Illuminating Engineering Laboratory for 18 years, then the Research Laboratory for 20 years until retiring in July 1948. He was working as a research physicist when he made the rediscovery of Benford's law, and spent years collecting data before publishing in 1938, citing more than 20,000 values from a diverse set of sources including statistics from baseball, atomic weights, the areas of rivers and numbering of articles in magazines.
Death
He died suddenly at his home on December 4, 1948.
References
1883 births
1948 deaths
People from Johnstown, Pennsylvania
University of Michigan alumni
20th-century American physicists
Information theory
Optical engineers
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https://en.wikipedia.org/wiki/Fluctuation%20loss
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Fluctuation loss is an effect seen in radar systems as the target object moves or changes its orientation relative to the radar system. It was extensively studied during the 1950s by Peter Swerling, who introduced the Swerling models to allow the effect to be simulated. For this reason, it is sometimes known as Swerling loss or similar names.
The effect occurs when the target's physical size is within a key range of values relative to the wavelength of the radar signal. As the signal reflects off various parts of the target, they may interfere as they return to the radar receiver. At any single distance from the station, this will cause the signal to be amplified or diminished compared to the baseline signal one calculates from the radar equation. As the target moves, these patterns change. This causes the signal to fluctuate in strength and may cause it to disappear entirely at certain times.
The effect can be reduced or eliminated by operating on more than one frequency or using modulation techniques like pulse compression that change the frequency over the period of a pulse. In these cases, it is unlikely that the pattern of reflections from the target causes the same destructive interference at two different frequencies.
Swerling modeled these effects in a famous 1954 paper introduced while working at RAND Corporation. Swerling's models considered the contribution of multiple small reflectors, or many small reflectors and a single large one. This offered the ability to model real-world objects like aircraft to understand the expected fluctuation loss effects.
Fluctuation loss
For basic considerations of the strength of a signal returned by a given target, the radar equation models the target as a single point in space with a given radar cross-section (RCS). The RCS is difficult to estimate except for the most basic cases, like a perpendicular surface or a sphere. Before the introduction of detailed computer modeling, the RCS for real-world objects was gener
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https://en.wikipedia.org/wiki/Memory%20T%20cell
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Memory T cells are a subset of T lymphocytes that might have some of the same functions as memory B cells. Their lineage is unclear.
Function
Antigen-specific memory T cells specific to viruses or other microbial molecules can be found in both central memory T cells (TCM) and effector memory T cells (TEM) subsets. Although most information is currently based on observations in the cytotoxic T cells (CD8-positive) subset, similar populations appear to exist for both the helper T cells (CD4-positive) and the cytotoxic T cells. Primary function of memory cells is augmented immune response after reactivation of those cells by reintroduction of relevant pathogen into the body. It is important to note that this field is intensively studied and some information may not be available as of yet.
Central memory T cells (TCM): TCM lymphocytes have several attributes in common with stem cells, the most important being the ability of self-renewal, mainly because of high level of phosphorylation on key transcription factor STAT5. In mice, TCM proved to confer more powerful immunity against viruses, bacteria and cancer cells, compared to TEM lymphocytes in several experimental models.
Effector memory T cells (TEM): TEM and TEMRA lymphocytes are primarily active as the CD8 variants, thus being mainly responsible for cytotoxic action against pathogens.
Tissue-resident memory T cell (TRM): Because TRM lymphocytes are present over long periods of time in tissues, or more importantly, barrier tissues (epithelium for example), they are crucial for quick response to barrier breach and response to any relevant pathogen present. One mechanism used by TRM to restrict pathogens is the secretion of granzyme B.
Stem cell-like memory T cells (TSCM): Those lymphocytes are capable of self-renewal as are the TCM lymphocytes and are also capable of generating both the TCM and TEM subpopulations. Presence of this population in humans is currently under investigation.
Virtual memory T cell (TV
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https://en.wikipedia.org/wiki/Compartment%20%28development%29
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Compartments can be simply defined as separate, different, adjacent cell populations, which upon juxtaposition, create a lineage boundary. This boundary prevents cell movement from cells from different lineages across this barrier, restricting them to their compartment. Subdivisions are established by morphogen gradients and maintained by local cell-cell interactions, providing functional units with domains of different regulatory genes, which give rise to distinct fates.
Compartment boundaries are found across species. In the hindbrain of vertebrate embryos, rhombomeres are compartments of common lineage outlined by expression of Hox genes. In invertebrates, the wing imaginal disc of Drosophila provides an excellent model for the study of compartments. Although other tissues, such as the abdomen, and even other imaginal discs are compartmentalized, much of our understanding of key concepts and molecular mechanisms involved in compartment boundaries has been derived from experimentation in the wing disc of the fruit fly.
Function
By separating different cell populations, the fate of these compartments are highly organized and regulated. In addition, this separation creates a region of specialized cells close to the boundary, which serves as a signaling center for the patterning, polarizing and proliferation of the entire disc. Compartment boundaries establish these organizing centers by providing the source of morphogens that are responsible for the positional information required for development and regeneration.
The inability of cell competition to occur across the boundary, indicates that each compartment serves as an autonomous unit of growth. Differences in growth rates and patterns in each compartment, maintain the two lineages separated and each control the precise size of the imaginal discs.
Cell separation
These two cell populations are kept separate by a mechanism of cell segregation linked to the heritable expression of a selector gene. A select
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https://en.wikipedia.org/wiki/Inferential%20programming
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In most computer programming, a programmer keeps a program's intended results in mind and painstakingly constructs a program to achieve those results. Inferential programming refers to (still mostly hypothetical) techniques and technologies enabling the inverse. This would allow describing an intended result to a computer, using a metaphor such as a fitness function, a test specification, or a logical specification, and then the computer, on its own, would construct a program needed to meet the supplied criteria.
During the 1980s, approaches to achieve inferential programming mostly involved techniques for logical inference. Today the term is sometimes used in connection with evolutionary computation techniques that enable a computer to evolve a solution in response to a problem posed as a fitness or reward function.
In July 2022, GitHub Copilot was released, which is an example of inferential programming.
Closely related concepts and technologies
Logic programming
Prolog
Constraint programming
Artificial intelligence
Genetic programming
Machine learning
Artificial life
Evolution
Metaprogramming
See also
Automated reasoning
Compiler theory
Unit testing
References
External links
First steps towards inferential programming
Programming paradigms
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https://en.wikipedia.org/wiki/Proanthocyanidin
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Proanthocyanidins are a class of polyphenols found in many plants, such as cranberry, blueberry, and grape seeds. Chemically, they are oligomeric flavonoids. Many are oligomers of catechin and epicatechin and their gallic acid esters. More complex polyphenols, having the same polymeric building block, form the group of tannins.
Proanthocyanidins were discovered in 1947 by Jacques Masquelier, who developed and patented techniques for the extraction of oligomeric proanthocyanidins from pine bark and grape seeds. Proanthocyanidins are under preliminary research for the potential to reduce the risk of urinary tract infections (UTIs) by consuming cranberries, grape seeds or red wine.
Distribution in plants
Proanthocyanidins, including the lesser bioactive and bioavailable polymers (four or more catechins), represent a group of condensed flavan-3-ols, such as procyanidins, prodelphinidins and propelargonidins. They can be found in many plants, most notably apples, maritime pine bark and that of most other pine species, cinnamon, aronia fruit, cocoa beans, grape seed, grape skin (procyanidins and prodelphinidins), and red wines of Vitis vinifera (the European wine grape). However, bilberry, cranberry, black currant, green tea, black tea, and other plants also contain these flavonoids. Cocoa beans contain the highest concentrations. Proanthocyanidins also may be isolated from Quercus petraea and Q. robur heartwood (wine barrel oaks). Açaí oil, obtained from the fruit of the açaí palm (Euterpe oleracea), is rich in numerous procyanidin oligomers.
Apples contain on average per serving about eight times the amount of proanthocyanidin found in wine, with some of the highest amounts found in the Red Delicious and Granny Smith varieties.
An extract of maritime pine bark called Pycnogenol bears 65–75 percent proanthocyanidins (procyanidins). Thus a 100 mg serving would contain 65 to 75 mg of proanthocyanidins (procyanidins).
Proanthocyanidin glycosides can be isolated from
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https://en.wikipedia.org/wiki/Copenhagen%20disease
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Copenhagen disease, sometimes known as Copenhagen syndrome or progressive non-infectious anterior vertebral fusion (PAVF), is a unique spinal disorder with distinctive radiological features. This is a rare childhood disease of unknown cause, affecting females slightly more than males (60%). Prevalence is unknown, but there have been approximately 80–100 individuals with Copenhagen disease reported since 1949. However, there is still little known research due to the rarity of the disease. The disease is so rare that the National Organization for Rare Diseases does not even mention Copenhagen disease in their database.
Copenhagen disease affects the lower back, as can be seen on MRI scans. It is characterized by the progressive fusion of the anterior vertebral body in the thoracolumbar region of the spine.
Presentation
Individuals with Copenhagen disease are often asymptomatic, but some may present with symptoms including back pain, difficulty walking, and stiffness of the spine, including neck and back, with kyphosis. Kyphosis can progress to angles of up to 85 degrees. Complete bony ankylosis occurs as the disease progresses over the years.
Radiological findings may show anterior deformities in end plates, which is related to narrowing between vertebrae in specific areas. Erosion and irregularity of corresponding end plates is also seen. This is followed by fusion, however fusion is usually not seen in the posterior disc space except in later stages of the disease.
Signs and symptoms
Clinical studies and case reports
15‐year‐old male
A 15-year-old male presented with major thoracolumbar kyphosis with spinal stiffness. However, there was no presentation of pain, scoliosis, neurologic symptoms, or trouble with ambulating. Through a combination of MRI of the spine, radiography findings, and absence of sacroiliac joint movement, Copenhagen disease was diagnosed. In this individual, exam findings showed anterior vertebral body fusion, as well as multilevel lumbar
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https://en.wikipedia.org/wiki/TR-069
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Technical Report 069 (TR-069) is a technical specification of the Broadband Forum that defines an application layer protocol for remote management and provisioning of customer-premises equipment (CPE) connected to an Internet Protocol (IP) network. TR-069 uses the CPE WAN Management Protocol (CWMP) which provides support functions for auto-configuration, software or firmware image management, software module management, status and performance managements, and diagnostics.
The CPE WAN Management Protocol is a bidirectional SOAP- and HTTP-based protocol, and provides the communication between a CPE and auto configuration servers (ACS). The protocol addresses the growing number of different Internet access devices such as modems, routers, gateways, as well as end-user devices which connect to the Internet, such as set-top boxes, and VoIP-phones.
TR-069 was first published in May 2004, with amendments in 2006, 2007, 2010, July 2011 (version 1.3), and November 2013 (version 1.4 am5)
Other technical initiatives, such as the Home Gateway Initiative (HGI), Digital Video Broadcasting (DVB) and WiMAX Forum endorsed CWMP as the protocol for remote management of residential networking devices and terminals.
Communication
Transport
CWMP is a text based protocol. Orders sent between the device (CPE) and auto configuration server (ACS) are transported over HTTP (or more frequently HTTPS). At this level (HTTP), the CPE acts as client and ACS as HTTP server. This essentially means that control over the flow of the provisioning session is the sole responsibility of the device.
Configuration parameters
In order for the device to connect to the server, it needs to have certain parameters configured first. These include the URL of the server the device wants to connect to and the interval at which the device will initiate the provisioning session (PeriodicInformInterval). Additionally, if authentication is required for security reasons, data such as the username and the password
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https://en.wikipedia.org/wiki/Sockets%20Direct%20Protocol
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The Sockets Direct Protocol (SDP) is a transport-agnostic protocol to support stream sockets over remote direct memory access (RDMA) network fabrics. SDP was originally defined by the Software Working Group (SWG) of the InfiniBand Trade Association. Originally designed for InfiniBand (IB), SDP is currently maintained by the OpenFabrics Alliance.
Protocol
SDP defines a standard wire protocol over an RDMA fabric to support stream sockets (SOCK_STREAM). SDP uses various RDMA network features for high-performance zero-copy data transfers. SDP is a pure wire-protocol level specification and does not go into any socket API or implementation specifics.
The purpose of the Sockets Direct Protocol is to provide an RDMA-accelerated alternative to the TCP protocol on IP. The goal is to do this in a manner which is transparent to the application.
Solaris 10 and Solaris 11 Express include support for SDP. Several other Unix operating system variants plan to include support for Sockets Direct Protocol. Windows offers a subsystem called Winsock Direct, which could be used to support SDP.
SDP support was introduced to the JDK 7 release of the Java Platform, Standard Edition (July 2011) for applications deployed in on Solaris and Linux operating systems (OFED 1.4.2 and 1.5). Oracle Database 11g supports connection over SDP.
Sockets Direct Protocol only deals with stream sockets, and if installed in a system, bypasses the OS resident TCP stack for stream connections between any endpoints on the RDMA fabric. All other socket types (such as datagram, raw, packet, etc.) are supported by the Linux IP stack and operate over standard IP interfaces (i.e., IPoIB on InfiniBand fabrics). The IP stack has no dependency on the SDP stack; however, the SDP stack depends on IP drivers for local IP assignments and for IP address resolution for endpoint identifications.
SDP is used by the Australian telecommunications company Telstra on their 3G platform Next G to deliver streaming mobile TV.
T
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https://en.wikipedia.org/wiki/Chemotaxonomy
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Merriam-Webster defines chemotaxonomy as the method of biological classification based on similarities and dissimilarity in the structure of certain compounds among the organisms being classified. Advocates argue that, as proteins are more closely controlled by genes and less subjected to natural selection than the anatomical features, they are more reliable indicators of genetic relationships. The compounds studied most are proteins, amino acids, nucleic acids, peptides etc.
Physiology is the study of working of organs in a living being. Since working of the organs involves chemicals of the body, these compounds are called biochemical evidences. The study of morphological change has shown that there are changes in the structure of animals which result in evolution. When changes take place in the structure of a living organism, they will naturally be accompanied by changes in the physiological or biochemical processes.
John Griffith Vaughan was one of the pioneers of chemotaxonomy.
Biochemical products
The body of any animal in the animal kingdom is made up of a number of chemicals. Of these, only a few biochemical products have been taken into consideration to derive evidence for evolution.
Protoplasm: Every living cell, from a bacterium to an elephant, from grasses to the blue whale, has protoplasm. Though the complexity and constituents of the protoplasm increases from lower to higher living organism, the basic compound is always the protoplasm. Evolutionary significance: From this evidence, it is clear that all living things have a common origin point or a common ancestor, which in turn had protoplasm. Its complexity increased due to changes in the mode of life and habitat.
Nucleic acids: DNA and RNA are the two types of nucleic acids present in all living organisms. They are present in the chromosomes. The structure of these acids has been found to be similar in all animals. DNA always has two chains forming a double helix, and each chain is made up of nuc
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https://en.wikipedia.org/wiki/Hemangioblast
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Hemangioblasts are the multipotent precursor cells that can differentiate into both hematopoietic and endothelial cells. In the mouse embryo, the emergence of blood islands in the yolk sac at embryonic day 7 marks the onset of hematopoiesis. From these blood islands, the hematopoietic cells and vasculature are formed shortly after. Hemangioblasts are the progenitors that form the blood islands. To date, the hemangioblast has been identified in human, mouse and zebrafish embryos.
Hemangioblasts have been first extracted from embryonic cultures and manipulated by cytokines to differentiate along either hematopoietic or endothelial route. It has been shown that these pre-endothelial/pre-hematopoietic cells in the embryo arise out of a phenotype CD34 population. It was then found that hemangioblasts are also present in the tissue of post-natal individuals, such as in newborn infants and adults.
Adult hemangioblast
There is now emerging evidence of hemangioblasts that continue to exist in the adult as circulating stem cells in the peripheral blood that can give rise to both endothelial cells and hematopoietic cells. These cells are thought to express both CD34 and CD133 These cells are likely derived from the bone marrow, and may even be derived from hematopoietic stem cells.
History
The hemangioblast was first hypothesized in 1900 by Wilhelm His. Existence of the hemangioblast was first proposed in 1917 by Florence Sabin, who observed the close spatial and temporal proximity of the emergence of blood vessels and red blood cells within the yolk sac in chick embryos. In 1932, making the same observation as Sabin, Murray coined the term “hemangioblast”.
The hypothesis of a bipotential precursor was further supported by the fact that endothelial cells and hematopoietic cells share many of the same markers, including Flk1, Vegf, CD34, Scl, Gata2, Runx1, and Pecam-1. Furthermore, it was shown that depletion of Flk1 in the developing embryo results in disappearance of
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https://en.wikipedia.org/wiki/Fluorosilicate%20glass
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Fluorosilicate glass (FSG) is a glass material composed primarily of fluorine, silicon and oxygen. It has a number of uses in industry and manufacturing, especially in semiconductor fabrication where it forms an insulating dielectric. The related fluorosilicate glass-ceramics have good mechanical and chemical properties.
Semiconductor fabrication
FSG has a small relative dielectric constant (low-κ dielectric) and is used in between metal copper interconnect layers during silicon integrated circuit fabrication process. It is widely used by semiconductor fabrication plants on geometries under 0.25 microns (μ). FSG is effectively a fluorine-containing silicon dioxide (κ=3.5, while κ of undoped silicon dioxide is 3.9). FSG is used by IBM. Intel started using Cu metal layers and FSG on its 1.2 GHz Pentium processor at 130 nm complementary metal–oxide–semiconductor (CMOS). Taiwan Semiconductor Manufacturing Company (TSMC) combined FSG and copper in the Altera APEX.
Fluorosilicate glass-ceramics
Fluorosilicate glass-ceramics are crystalline or semi-crystalline solids formed by careful cooling of molten fluorosilicate glass. They have good mechanical properties.
Potassium fluororichterite based materials are composed from tiny interlocked rod-shaped amphibole crystals; they have good resistance to chemicals and can be used in microwave ovens. Richterite glass-ceramics are used for high-performance tableware.
Fluorosilicate glass-ceramics with sheet structure, derived from mica, are strong and machinable. They find a number of uses and can be used in high vacuum and as dielectrics and precision ceramic components. A number of mica and mica-fluoroapatite glass-ceramics were studied as biomaterials.
See also
Fluoride glass
Glass
Silicate
References
Silicates
Glass compositions
Integrated circuits
Semiconductor fabrication materials
Biomaterials
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https://en.wikipedia.org/wiki/Oracle%20Fusion%20Middleware
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Oracle Fusion Middleware (FMW, also known as Fusion Middleware) consists of several software products from Oracle Corporation. FMW spans multiple services, including Java EE and developer tools, integration services, business intelligence, collaboration, and content management. FMW depends on open standards such as BPEL, SOAP, XML and JMS.
Oracle Fusion Middleware provides software for the development, deployment, and management of service-oriented architecture (SOA). It includes what Oracle calls "hot-pluggable" architecture,
designed to facilitate integration with existing applications and systems from other software vendors such as IBM, Microsoft, and SAP AG.
Evolution
Many of the products included under the FMW banner do not themselves qualify as middleware products: "Fusion Middleware" essentially represents a re-branding of many of Oracle products outside of Oracle's core database and applications-software offerings—compare Oracle Fusion.
Oracle acquired many of its FMW products via acquisitions. This includes products from BEA Systems and Stellent.
In order to provide standards-based software to assist with business process automation, HP has incorporated FMW into its "service-oriented architecture (SOA) portfolio".
Oracle leveraged its Configurable Network Computing (CNC) technology acquired from its PeopleSoft/JD Edwards 2005 purchase.
Oracle Fusion Applications, based on Oracle Fusion Middleware, were finally released in September 2010.
According to Oracle, as of 2013, over 120,000 customers were using Fusion Middleware. This includes over 35 of the world's 50 largest companies and more than 750 of the BusinessWeek Global 1000, with FMW also supported by 7,500 partners.
Assessments
In January 2008, Oracle WebCenter Content (formerly Universal Content Management) won InfoWorld's "Technology of the Year" award for "Best Enterprise Content Manager", with Oracle SOA Suite winning the award for "Best Enterprise Service Bus".
In 2007, Gartner wrote th
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https://en.wikipedia.org/wiki/Wratten%20number
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Wratten numbers are a labeling system for optical filters, usually for photographic use comprising a number sometimes followed by a letter. The number denotes the color of the filter, but is arbitrary and does not encode any information (the 80A–80D are blue, the next filters in numerical order, 81A–81EF, are orange); letters almost always increase with increasing strength (the exception being 2B, 2A, 2C, 2E).
They are named for the founder of the first photography company, British inventor Frederick Wratten. Wratten and partner C.E.K. Mees sold their company to Eastman Kodak in 1912, and Kodak started manufacturing Wratten filters. They remain in production, and are sold under license through the Tiffen corporation.
Wratten filters are often used in observational astronomy by amateur astronomers. Color filters for visual observing made by GSO, Baader, Lumicon, or other companies are actually Wratten filters mounted in standard or 2 in (nominal, 48 mm actual) filter threads. For imaging interference filters are used. Wratten filters are also used in photomicrography.
Filters made by various manufacturers may be identified by Wratten numbers but not precisely match the spectral definition for that number. This is especially true for filters used for aesthetic (as opposed to technical) reasons. For example, an 81B warming filter is a filter used to slightly "warm" the colors in a color photo, making the scene a bit less blue and more red. Many manufacturers make filters labeled as 81B with transmission curves which are similar, but not identical, to the Kodak Wratten 81B. This is according to that manufacturer's idea of how best to warm a scene, and depending on the dyes and layering techniques used in manufacturing. Some manufacturers use their own designations to avoid this confusion, for example Singh-Ray has a warming filter which they designate A‑13, which is not a Wratten number. Filters used where precisely specified and repeatable characteristics are requi
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https://en.wikipedia.org/wiki/Microserver
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A data center 64 bit microserver is a server class computer which is based on a system on a chip (SoC). The goal is to integrate all of the server motherboard functions onto a single microchip, except DRAM, boot FLASH and power circuits. Thus, the main chip contains more than only compute cores, caches, memory interfaces and PCI controllers. It typically also contains SATA, networking, serial port and boot FLASH interfaces on the same chip. This eliminates support chips (and therefore area, power and cost) at the board level. Multiple microservers can be put together in a small package to construct dense data center (example: DOME MicroDataCenter).
History
The term "microserver" first appeared in the late 1990s and was popularized by a Palo Alto incubator; PicoStar when incubating Cobalt Microservers. Microserver again appeared around 2010 and is commonly misunderstood to imply low performance. Microservers first appeared in the embedded market, where due to cost and space these types of SoCs appeared before they did in general purpose computing. Indeed, recent research indicates that emerging scale-out services and popular datacenter workloads (e.g., as in CloudSuite) require a certain degree of single-thread performance (with out-of-order execution cores) which may be lower than those in conventional desktop processors but much higher than those in the embedded systems.
A modern microserver typically offers medium-high performance at high packaging densities, allowing very small compute node form factors. This can result in high energy efficiency (operations per Watt), typically better than that of highest single-thread performance processors.
One of the early microservers is the 32-bit SheevaPlug. There are plenty of consumer grade 32-bit microservers available, for instance the Banana Pi as seen on Comparison of single-board computers. Early 2015, even a 64-bit consumer grade microserver is announced. Mid 2017 consumer-grade 64-bit microservers started app
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https://en.wikipedia.org/wiki/Game%20development%20tool
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A game development tool is a specialized software application that assists or facilitates the making of a video game. Some tasks handled by tools include the conversion of assets (such as 3D models, textures, etc.) into formats required by the game, level editing and script compilation.
Almost all game development tools are developed by the developer custom for one game, or by a console manufacturer (such as Nintendo or Microsoft) as part of a game development kit. Though tools may be re-used for later games, they almost always start out as a resource for a single game. While many COTS packages are used in the production of games—such as 3D packages like Maya and 3D Studio Max, graphic editors like Photoshop and IDEs like Microsoft Visual Studio—they are not considered solely game development tools since they have uses beyond game development.
The game tools may or may not be released along with the final game, depending on what the tool is used for. For contemporary games, it is common to include at least level editors with games that require them.
History
Early in the history of the video game industry, game programming tools were non-existent. This wasn't a hindrance for the types of games that could be created at the time, however. While today a game like Pac-Man would most likely have levels generated with a level editor, in the industry's infancy, such levels were hard coded into the game's source code.
Images of the player's character were also hard-coded, being drawn, frame by frame, by source code commands. As soon as the more technologically advanced use of sprites became common, game development tools began to emerge, custom programmed by the programmer. Today, game development tools are still often programmed by members of the game development team by programmers, often whose sole job is to develop and maintain tools.
Examples
Bitsy: A game development tool featured exclusively at itch.io
RPG Maker, known in Japan as RPG Tsukūru for the dev
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https://en.wikipedia.org/wiki/Ephemeral%20key
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A cryptographic key is called ephemeral if it is generated for each execution of a key establishment process. In some cases ephemeral keys are used more than once, within a single session (e.g., in broadcast applications) where the sender generates only one ephemeral key pair per message and the private key is combined separately with each recipient's public key. Contrast with a static key.
Private / public ephemeral key agreement key
Private (resp. public) ephemeral key agreement keys are the private (resp. public) keys of asymmetric key pairs that are used a single key establishment transaction to establish one or more keys (e.g., key wrapping keys, data encryption keys, or MAC keys) and, optionally, other keying material (e.g., initialization vectors).
See also
Cryptographic key types
Session key
External links
Recommendation for Key Management — Part 1: General, NIST Special Publication 800-57
NIST Cryptographic Toolkit
References
Key management
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https://en.wikipedia.org/wiki/Eye%20%28cyclone%29
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The eye is a region of mostly calm weather at the center of a tropical cyclone. The eye of a storm is a roughly circular area, typically in diameter. It is surrounded by the eyewall, a ring of towering thunderstorms where the most severe weather and highest winds of the cyclone occur. The cyclone's lowest barometric pressure occurs in the eye and can be as much as 15 percent lower than the pressure outside the storm.
In strong tropical cyclones, the eye is characterized by light winds and clear skies, surrounded on all sides by a towering, symmetric eyewall. In weaker tropical cyclones, the eye is less well defined and can be covered by the central dense overcast, an area of high, thick clouds that show up brightly on satellite imagery. Weaker or disorganized storms may also feature an eyewall that does not completely encircle the eye or have an eye that features heavy rain. In all storms, however, the eye is where the barometer reading is lowest.
Structure
A typical tropical cyclone has an eye approximately 30–65km (20–40mi) across at the geometric center of the storm. The eye may be clear or have spotty low clouds (a clear eye), it may be filled with low- and mid-level clouds (a filled eye), or it may be obscured by the central dense overcast. There is, however, very little wind and rain, especially near the center. This is in stark contrast to conditions in the eyewall, which contains the storm's strongest winds. Due to the mechanics of a tropical cyclone, the eye and the air directly above it are warmer than their surroundings.
While normally quite symmetric, eyes can be oblong and irregular, especially in weakening storms. A large ragged eye is a non-circular eye which appears fragmented, and is an indicator of a weak or weakening tropical cyclone. An open eye is an eye which can be circular, but the eyewall does not completely encircle the eye, also indicating a weakening, moisture-deprived cyclone or a weak but strengthening one. Both of these observatio
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https://en.wikipedia.org/wiki/Strehl%20ratio
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The Strehl ratio is a measure of the quality of optical image formation, originally proposed by Karl Strehl, after whom the term is named. Used variously in situations where optical resolution is compromised due to lens aberrations or due to imaging through the turbulent atmosphere, the Strehl ratio has a value between 0 and 1, with a hypothetical, perfectly unaberrated optical system having a Strehl ratio of 1.
Mathematical definition
The Strehl ratio is frequently defined as the ratio of the peak aberrated image intensity from a point source compared to the maximum attainable intensity using an ideal optical system limited only by diffraction over the system's aperture. It is also often expressed in terms not of the peak intensity but the intensity at the image center (intersection of the optical axis with the focal plane) due to an on-axis source; in most important cases these definitions result in a very similar figure (or identical figure, when the point of peak intensity must be exactly at the center due to symmetry). Using the latter definition, the Strehl ratio can be computed in terms of the wavefront-error : the offset of the wavefront due to an on-axis point source, compared to that produced by an ideal focusing system over the aperture A(x,y). Using Fraunhofer diffraction theory, one computes the wave amplitude using the Fourier transform of the aberrated pupil function evaluated at 0,0 (center of the image plane) where the phase factors of the Fourier transform formula are reduced to unity. Since the Strehl ratio refers to intensity, it is found from the squared magnitude of that amplitude:
where i is the imaginary unit, is the phase error over the aperture at wavelength λ, and the average of the complex quantity inside the brackets is taken over the aperture A(x,y).
The Strehl ratio can be estimated using only the statistics of the phase deviation
, according to a formula rediscovered by Mahajan but known long before in antenna theory as the Ruz
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https://en.wikipedia.org/wiki/Cavium
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Cavium was a fabless semiconductor company based in San Jose, California, specializing in ARM-based and MIPS-based network, video and security processors and SoCs. The company was co-founded in 2000 by Syed B. Ali and M. Raghib Hussain, who were introduced to each other by a Silicon Valley entrepreneur. Cavium offers processor- and board-level products targeting routers, switches, appliances, storage and servers.
The company went public in May 2007 with about 175 employees. As of 2011, following numerous acquisitions, it had about 850 employees worldwide, of whom about 250 were located at company headquarters in San Jose.
Cavium was acquired by Marvell Technology Group on July 6, 2018.
History
Name change
On June 17, 2011, Cavium Networks, Inc. changed their name to Cavium, Inc.
Acquisitions
Acquisition
In November 2017, Cavium's board of directors agreed to the company's purchase by Marvell Technology Group for $6 billion in cash and stock. The merger was finalized on July 6, 2018.
NSA Interference
On March 23, 2022, Cavium was named as an NSA "enabled" CPU vendor in a PhD thesis titled "Communication in a world of pervasive surveillance". The "enabled" term refers to a process with which a chip vendor has a backdoor introduced into their designs.
References
Semiconductor companies of the United States
Networking companies of the United States
Companies formerly listed on the Nasdaq
Companies based in San Jose, California
Electronics companies established in 2001
American companies established in 2001
Fabless semiconductor companies
2018 mergers and acquisitions
American corporate subsidiaries
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https://en.wikipedia.org/wiki/StegFS
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StegFS is a free steganographic file system for Linux based on the ext2 filesystem. It is licensed under the GPL. It was principally developed by Andrew D. McDonald and Markus G. Kuhn.
The last version of StegFS is 1.1.4, released February 14, 2001. This is a development release, with known bugs, such as a file corruption bug. There is no stable release. The last website activity was in 2004. In 2003, Andreas C. Petter and Sebastian Urbach intended to continue development of StegFS, and created a site for it on SourceForge.net. The development has further moved to using FUSE library, and working releases are available from the development homepage.
See also
Filesystem-level encryption
List of cryptographic file systems
Further reading
External links
StegFS original home page
StegFS development home page
StegFS research paper -(PDF file)
StegFS SourceForge project page
Disk file systems
Free special-purpose file systems
File systems supported by the Linux kernel
Steganography
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https://en.wikipedia.org/wiki/Underhanded%20C%20Contest
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The Underhanded C Contest is a programming contest to turn out code that is malicious, but passes a rigorous inspection, and looks like an honest mistake even if discovered. The contest rules define a task, and a malicious component. Entries must perform the task in a malicious manner as defined by the contest, and hide the malice. Contestants are allowed to use C-like compiled languages to make their programs.
The contest was organized by Dr. Scott Craver of the Department of Electrical Engineering at Binghamton University. The contest was initially inspired by Daniel Horn's Obfuscated V contest in the fall of 2004. For the 2005 to 2008 contests, the prize was a $100 gift certificate to ThinkGeek. The 2009 contest had its prize increased to $200 due to the very late announcement of winners, and the prize for the 2013 contest is also a $200 gift certificate.
Contests
2005
The 2005 contest had the task of basic image processing, such as resampling or smoothing, but covertly inserting unique and useful "fingerprinting" data into the image. Winning entries from 2005 used uninitialized data structures, reuse of pointers, and an embedding of machine code in constants.
2006
The 2006 contest required entries to count word occurrences, but have vastly different runtimes on different platforms. To accomplish the task, entries used fork implementation errors, optimization problems, endian differences and various API implementation differences. The winner called strlen() in a loop, leading to quadratic complexity which was optimized out by a Linux compiler but not by Windows.
2007
The 2007 contest required entries to encrypt and decrypt files with a strong, readily available encryption algorithm such that a low percentage (1% - 0.01%) of the encrypted files may be cracked in a reasonably short time. The contest commenced on April 16 and ended on July 4. Entries used misimplementations of RC4, misused API calls, and incorrect function prototypes.
2008
The 2008 contest re
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https://en.wikipedia.org/wiki/Steganographic%20file%20system
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Steganographic file systems are a kind of file system first proposed by Ross Anderson, Roger Needham, and Adi Shamir. Their paper proposed two main methods of hiding data: in a series of fixed size files originally consisting of random bits on top of which 'vectors' could be superimposed in such a way as to allow levels of security to decrypt all lower levels but not even know of the existence of any higher levels, or an entire partition is filled with random bits and files hidden in it.
In a steganographic file system using the second scheme, files are not merely stored, nor stored encrypted, but the entire partition is randomized - encrypted files strongly resemble randomized sections of the partition, and so when files are stored on the partition, there is no easy way to discern between meaningless gibberish and the actual encrypted files. Furthermore, locations of files are derived from the key for the files, and the locations are hidden and available to only programs with the passphrase. This leads to the problem that very quickly files can overwrite each other (because of the Birthday Paradox); this is compensated for by writing all files in multiple places to lessen the chance of data loss.
Advantage
While there may seem to be no point to a file system which is guaranteed to either be grossly inefficient storage space-wise or to cause data loss and corruption either from data collisions or loss of the key (in addition to being a complex system, and for having poor read/write performance), performance was not the goal of StegFS. Rather, StegFS is intended to thwart "rubberhose attacks", which usually work because encrypted files are distinguishable from regular files, and authorities can coerce the user until the user gives up the keys and all the files are distinguishable as regular files. However, since in a steganographic file system, the number of files are unknown and every byte looks like an encrypted byte, the authorities cannot know how many files
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https://en.wikipedia.org/wiki/Tokyo%20tanks
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Tokyo tanks were internally mounted self-sealing fuel tanks used in the Boeing B-17 Flying Fortress and Consolidated B-24 Liberator bombers during World War II. Although nicknamed "Tokyo" tanks to dramatically illustrate the significant range they added to the B-17 (approximately 40% greater with combat weights), it was also an exaggeration in that no B-17 ever had the range to bomb Japan from any base in World War II.
Description
These fuel tanks consisted of eighteen removable containers made of a rubberized compound, called cells, installed inside the wings of the airplane, nine to each side. The wings of the B-17 consisted of an "inboard wing" structure mounted to the fuselage which held the engines and flaps, and an "outboard wing" structure joined to the inboard wing and carrying the ailerons. The Tokyo tanks were installed on either side of the joint (a load-bearing point) where the two wing portions were connected. Five cells, totaling capacity, sat side by side in the outboard wing and were joined by a fuel line to the main tank delivering fuel to the outboard engine. The sixth cell was located in the space where the wing sections joined, and the remaining three cells were located side-by-side in the inboard wing; these four cells delivered of fuel to the feeder tank for the inboard engine. The same arrangement was repeated on the opposite wing. The Tokyo tanks added of fuel to the already carried in the six regular wing tanks and the that could be carried in an auxiliary tank that could be mounted in the bomb bay, for a combined total of .
All B-17F aircraft built by Boeing from Block 80, by Douglas from Block 25, and by Vega from Block 30 were equipped with Tokyo tanks, and the entire run of B-17Gs by all three manufacturers had Tokyo tanks. B-17s with factory-mounted Tokyo tanks were first introduced to the Eighth Air Force in England in April 1943 with the arrival of the 94th and 95th Bomb Groups, equipped with new aircraft. By June 1943, aircra
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https://en.wikipedia.org/wiki/Economizer
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Economizers (US and Oxford spelling), or economisers (UK), are mechanical devices intended to reduce energy consumption, or to perform useful function such as preheating a fluid. The term economizer is used for other purposes as well. Boiler, power plant, heating, refrigeration, ventilating, and air conditioning (HVAC) uses are discussed in this article. In simple terms, an economizer is a heat exchanger.
Stirling engine
Robert Stirling's innovative contribution to the design of hot air engines of 1816 was what he called the 'Economiser'. Now known as the regenerator, it stored heat from the hot portion of the engine as the air passed to the cold side, and released heat to the cooled air as it returned to the hot side. This innovation improved the efficiency of the Stirling engine enough to make it commercially successful in particular applications, and has since been a component of every air engine that is called a Stirling engine.
Boilers
In boilers, economizers are heat exchange devices that heat fluids, usually water, up to but not normally beyond the boiling point of that fluid. Economizers are so named because they can make use of the enthalpy in fluid streams that are hot, but not hot enough to be used in a boiler, thereby recovering more useful enthalpy and improving the boiler's efficiency. They are a device fitted to a boiler which saves energy by using the exhaust gases from the boiler to preheat the cold water used to fill it (the feed water).
Steam boilers use large amounts of energy raising feed water to the boiling temperature, converting the water to steam and sometimes superheating that steam above saturation temperature. Heat transfer efficiency is improved when the highest temperatures near the combustion sources are used for boiling and superheating, while using the residual heat of the cooled combustion gases exhausting from the boiler through an economizer to raise the temperature of feed water entering the steam drum.
An indirect conta
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https://en.wikipedia.org/wiki/Diffuser%20%28thermodynamics%29
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A diffuser is "a device for reducing the velocity and increasing the static pressure of a fluid passing through a system”. The fluid's static pressure rise as it passes through a duct is commonly referred to as pressure recovery. In contrast, a nozzle is used to increase the discharge velocity and lower the pressure of a fluid passing through it.
Frictional effects during analysis can sometimes be important, but usually they are neglected. Ducts containing fluids flowing at low velocity can usually be analyzed using Bernoulli's principle. Analyzing ducts flowing at higher velocities with Mach numbers in excess of 0.3 usually require compressible flow relations.
A typical subsonic diffuser is a duct that increases in area in the direction of flow. As the area increases, fluid velocity decreases, and static pressure rises.
Supersonic diffusers
A supersonic diffuser is a duct that decreases in area in the direction of flow which causes the fluid temperature, pressure, and density to increase, and velocity to decrease. These changes occur because the fluid is compressible. Shock waves may also play an important role in a supersonic diffuser.
Applications
Diffusers are very common in heating, ventilating, and air-conditioning systems. Diffusers are used in both all-air and air-water HVAC systems, as part of room air distribution subsystems, and serve several purposes:
To deliver both conditioning and ventilating air
Evenly distribute the flow of air, in the desired directions
To enhance mixing of room air into the primary air being discharged
Often to cause the air jet(s) to attach to a ceiling or other surface, taking advantage of the Coandă effect
To create low-velocity air movement in the occupied portion of room
Accomplish the above while producing the minimum amount of noise
When possible, dampers, extractors, and other flow control devices should not be placed near diffusers' inlets (necks), either not being used at all or being placed far upstrea
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https://en.wikipedia.org/wiki/Battle%20management%20language
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A Battle Management Language (BML) is the unambiguous language used to command and control forces and equipment conducting military operations and to provide for situational awareness and a shared, common operational picture.
It can be seen as a standard digitized representation of a commander's intent to be used for real troops, for simulated troops, and for future robotic forces. BML is particularly relevant in a network centric environment for enabling mutual understanding.
The need for common BML was identified by the U.S. Army's Simulation to C4I Interoperability Overarching Integrated Product Team (SIMCI OIPT) and was originally defined in a paper titled Standardizing Battle Management Language - A Vital Move Towards the Army Transformation published by the Simulation Interoperability Standards Organization in 2001 . The same issues that have driven the Army to embark on this program also confront the other Services C4ISR and simulation systems, and future military operations. Acknowledging the significant need for training in joint environments to support future operations, SISO and other BML development efforts have expanded to encompass Joint BML (J-BML) for all military branches and ultimately to more recent work on establishing a Coalition BML (C-BML) for all Services and multinational coalition members promoting interoperability among their C4ISR systems and simulations, and also among systems employed in real-world operations.
Coalition Battle Management Language
Coalition Battle Management Language (C-BML, CBML) is an unambiguous language to describe a commander's intent, to be understood by both live forces and automated systems, for multi-national simulated and real world operations. Following a meeting of subject matter experts at the Spring 2004 SIW, the Simulation Interoperability Standards Organization determined that a detailed evaluation of BML efforts at a coalition level was necessary and formally established a Coalition BML (C-BML) Stud
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https://en.wikipedia.org/wiki/Media%20Delivery%20Index
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The Media Delivery Index (MDI) is a set of measures that can be used to monitor both the quality of a delivered video stream as well as to show system margin for IPTV systems by providing an accurate measurement of jitter and delay at network level (Internet Protocol, IP), which are the main causes for quality loss. Identifying and quantizing such problems in this kind of networks is key to maintaining high quality video delivery and providing indications that warn system operators with enough advance notice to allow corrective action.
The Media Delivery Index is typically displayed as two numbers separated by a colon: the Delay Factor (DF) and the Media Loss Rate (MLR).
Context
The Media Delivery Index (MDI) may be able to identify problems caused by:
Time distortion
If packets are delayed by the network, some packets arrive in bursts with interpacket delays shorter than when they were transmitted, while others are delayed such that they arrive with greater delay between packets than when they were transmitted from the source (see figure below). This time difference between when a packet actually arrives and the expected arrival time is defined as packet jitter or time distortion.
A receiver displaying the video at its nominal rate must accommodate the varying input stream arrival times by buffering the data arriving early and assuring that there is enough already stored data to face the possible delays in the received data (because of this the buffer is filled before displaying).
Similarly, the network infrastructure (switches, routers,…) uses buffers at each node to avoid packet loss. These buffers must be sized appropriately to handle network congestion.
Packet delays can be caused by multiple facts, among which there are the way traffic is routed through the infrastructure and possible differences between link speeds in the infrastructure.
Moreover, some methods for delivering Quality of Service (QOS) using packet metering algorithms may intentionally h
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https://en.wikipedia.org/wiki/PyBOP
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PyBOP (benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate) is a peptide coupling reagent used in solid phase peptide synthesis. It is used as a substitute for the BOP reagent - avoiding the formation of the carcinogenic waste product HMPA.
See also
BOP reagent
DEPBT, a related reagent that contains no phosphorus-nitrogen bonds
HATU
HBTU
References
Hexafluorophosphates
Peptide coupling reagents
Benzotriazoles
1-Pyrrolidinyl compounds
Biochemistry
Biochemistry methods
Reagents for biochemistry
Quaternary phosphonium compounds
Organophosphorus compounds
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https://en.wikipedia.org/wiki/Fruity%20Frank
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Fruity Frank is a 1984 video game for the Amstrad CPC and MSX home computers. Produced by Kuma Software and authored by Steve Wallis with graphics by his brother Sean Wallis. The gameplay is very similar to Mr. Do!, though the story involves Frank protecting a garden from invading monsters.
Gameplay
The player has to collect the fruits lying around the garden while avoiding touching the monsters. Apples can be pushed on these to kill them and offer temporary respite. Monsters can also be killed by throwing a bouncing apple pip at them. When all pieces of fruit have been collected the player proceeds to the next level. Each level is identifiable by a different colour background and a new jocular tune.
There are four types of enemies:
the yellow "big nose", slow: 20 points by shooting, 40 points by squashing
the violet "eggplant", fast, digging: 50 points by shooting, 100 points by squashing
the red "strawberry", very fast, digging: 100 points by shooting, 200 points by squashing
the green (spelling "Bonus")
Every 1000 points, Frank gains an extra life, with a maximum of two.
Music
Music in the game is inspired from traditional English songs and rhymes.
Level 1 : "A Life on the Ocean Wave" (Royal Marines anthem)
Level 2 : "Where Have You Been All the Day, Billy Boy" (Irish version)
Level 3 : ???
Level 4 : "Sweet Molly Malone"
Level 5 : "The Jolly Beggar"
Level 6 : "My Bonnie Lies over the Ocean"
Level 7 : "London Bridge Is Falling Down"
References
External links
Fruity Frank at CPC Zone
Website of the creator of the game Steven Wallis
MSX games
Amstrad CPC games
1984 video games
Video games developed in the United Kingdom
Action games
Video game clones
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https://en.wikipedia.org/wiki/List%20of%20formulae%20involving%20%CF%80
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The following is a list of significant formulae involving the mathematical constant . Many of these formulae can be found in the article Pi, or the article Approximations of .
Euclidean geometry
where is the circumference of a circle, is the diameter, and is the radius. More generally,
where and are, respectively, the perimeter and the width of any curve of constant width.
where is the area of a circle. More generally,
where is the area enclosed by an ellipse with semi-major axis and semi-minor axis .
where is the area between the witch of Agnesi and its asymptotic line; is the radius of the defining circle.
where is the area of a squircle with minor radius , is the gamma function and is the arithmetic–geometric mean.
where is the area of an epicycloid with the smaller circle of radius and the larger circle of radius (), assuming the initial point lies on the larger circle.
where is the area of a rose with angular frequency () and amplitude .
where is the perimeter of the lemniscate of Bernoulli with focal distance .
where is the volume of a sphere and is the radius.
where is the surface area of a sphere and is the radius.
where is the hypervolume of a 3-sphere and is the radius.
where is the surface volume of a 3-sphere and is the radius.
Regular convex polygons
Sum of internal angles of a regular convex polygon with sides:
Area of a regular convex polygon with sides and side length :
Inradius of a regular convex polygon with sides and side length :
Circumradius of a regular convex polygon with sides and side length :
Physics
The cosmological constant:
Heisenberg's uncertainty principle:
Einstein's field equation of general relativity:
Coulomb's law for the electric force in vacuum:
Magnetic permeability of free space:
Approximate period of a simple pendulum with small amplitude:
Exact period of a simple pendulum with amplitude ( is the arithmetic–geometric mean):
Kepler's third law of planetary motion
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https://en.wikipedia.org/wiki/Deutschsprachige%20Anwendervereinigung%20TeX
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Deutschsprachige Anwendervereinigung TeX e. V., or DANTE e. V., is the German-language TeX users group. With about 2000 members, it is the largest TeX users group worldwide.
DANTE was founded on 14 April 1989 in the German city of Heidelberg by a handful of TeX enthusiasts who had met formerly on a non-regular basis.
According to its statutes, DANTE consults TeX users from all German-speaking countries and funds TeX-related projects. It also represents members towards other TeX users groups.
DANTE runs the main CTAN backbone server, .
Conferences with talks, tutorials and general member meetings are held bi-annually on changing locations all over the German-speaking countries. The conferences are free of charge for everyone interested in TeX.
The member journal, (German for "The TeXnical comedy", a pun on Dante's Divine Comedy referring back to the group's name), is published quarterly.
DANTE's international counterpart is the TeX Users Group (TUG) that was founded in 1980.
External links
DANTE, Deutschsprachige Anwendervereinigung TeX e. V.
TeX
User groups
1989 establishments in West Germany
Organizations established in 1989
Scientific organisations based in Germany
Heidelberg
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https://en.wikipedia.org/wiki/Chromium%28IV%29%20oxide
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Chromium dioxide or chromium(IV) oxide is an inorganic compound with the formula CrO2. It is a black synthetic magnetic solid. It once was widely used in magnetic tape emulsion. With the increasing popularity of CDs and DVDs, the use of chromium(IV) oxide has declined. However, it is still used in data tape applications for enterprise-class storage systems. It is still considered by many oxide and tape manufacturers to have been one of the best magnetic recording particulates ever invented.
Preparation and basic properties
CrO2 was first prepared by Friedrich Wöhler by decomposition of chromyl chloride. Acicular chromium dioxide was first synthesized in 1956 by Norman L. Cox, a chemist at E.I. DuPont, by decomposing chromium trioxide in the presence of water at a temperature of and a pressure of 200 MPa. The balanced equation for the hydrothermal synthesis is:
3 CrO3 + Cr2O3 → 5 CrO2 + O2
The magnetic crystal that forms is a long, slender glass-like rod — perfect as a magnetic pigment for recording tape. When commercialized in the late 1960s as a recording medium, DuPont assigned it the tradename of Magtrieve.
CrO2 adopts the rutile structure (as do many metal dioxides). As such, each Cr(IV) center has octahedral coordination geometry and each oxide is trigonal planar.
Uses
The crystal's magnetic properties, derived from its ideal shape such as anisotropy which imparted high coercivity and remanent magnetization intensities, resulted in exceptional stability and efficiency for short wavelengths, and it almost immediately appeared in high performance audio tape used in audio cassettes for which treble response and hiss were always problems. Unlike the imperfectly formed ferric oxide coating commonly used, the chromium dioxide crystals were perfectly formed and could be evenly and densely dispersed in a magnetic coating leading to higher signal-to-noise ratios in audio recordings. Chrome tapes did, however, require audio cassette recorders to be equi
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https://en.wikipedia.org/wiki/Media%20server
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A media server is a computer appliance or an application software that stores digital media (video, audio or images) and makes it available over a network.
Media servers range from servers that provide video on demand to smaller personal computers or NAS (Network Attached Storage) for the home.
Purpose
By definition, a media server is a device that simply stores and shares media. This definition is vague, and can allow several different devices to be called media servers. It may be a NAS drive, a home theater PC running Windows XP Media Center Edition, MediaPortal or MythTV, or a commercial web server that hosts media for a large web site. In a home setting, a media server acts as an aggregator of information: video, audio, photos, books, etc. These different types of media (whether they originated on DVD, CD, digital camera, or in physical form) are stored on the media server's hard drive. Access to these is then available from a central location. It may also be used to run special applications that allow the user(s) to access the media from a remote location via the internet.
Hardware
The only requirement for a media server is a method of storing media and a network connection with enough bandwidth to allow access to that media. Depending on the uses and applications that it runs, a media server may require large amounts of RAM, or a powerful multicore CPU. A RAID array may be used to create a large amount of storage, though it is generally not necessary in a home media server to use a RAID array that gives a performance increase because current home network transfer speeds are slower than that of most current hard drives. However, a RAID configuration may be used to prevent loss of the media files due to disk failure as well.
Many media servers also have the ability to capture media. This is done with specialized hardware such as TV tuner cards. Analog TV tuner cards can capture video from analog broadcast TV and output from cable/satellite set top boxes. Thi
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https://en.wikipedia.org/wiki/GeoDNS
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GeoDNS (or GeoIP) is a patch for BIND DNS server software, to allow geographical split horizon (different DNS answers based on client's geographical location), based on MaxMind's geoip (commercial) or geolite (free) databases.
The objective of this technology is to enhance the domain name lookup by address resolution based on the geographical location of the client. For example a website might have 2 servers, one located in France and one in the US. With GeoDNS it's possible to create a DNS record for which clients from Europe would get the IP address of the French server and clients from the US would get the American one. This makes network access faster and possibly cheaper, compared to directing all users worldwide to the same server or to multiple servers using random distribution, such as round robin.
As this technology is DNS based, it is much easier to deploy than BGP anycast. It does not require any support from the ISP and will not break existing connections when the server selected for a particular client changes. However, as it is not intimately tied into the network infrastructure it is likely to be less accurate at sending data to the nearest server.
The requester that the resolving DNS server sees is typically not the end user, but the DNS server of the user's ISP doing a recursive lookup, and the recursive DNS server caches the result. As ISPs typically arrange for users to use DNS servers geographically near them, the system usually works nonetheless.
External links
https://kb.isc.org/docs/aa-01149 BIND9 Documentation for GeoIP feature
http://news.constellix.com/dns-coach-digs-deeper-into-geoip-infographic/ Geo-IP Info graphic
DNS software
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https://en.wikipedia.org/wiki/Proto-mitochondrion
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The proto-mitochondrion is the hypothetical ancestral bacterial endosymbiont from which all mitochondria in eukaryotes are thought to descend, after an episode of symbiogenesis which created the aerobic eukaryotes.
Phylogeny
The phylogenetic analyses of the few genes that are still encoded in the genomes of modern mitochondria suggest an alphaproteobacterial origin for this endosymbiont, in an ancient episode of symbiogenesis early in the history of the eukaryotes. Although the order Rickettsiales has been proposed as the alphaproteobacterial sister-group of mitochondria, there is no definitive evidence as to which alphaproteobacterial group the proto-mitochondrion emerged from. Martijn et al found mitochondria are a possible sister-group to all other alphaproteobacteria. The phylogenetic tree of the Rickettsidae has been inferred by Ferla et al. from the comparison of 16S + 23S ribosomal RNA sequences.
Metabolism
Toni Gabaldón and Martijn Huynen (2003) reconstructed the proteome (the entire set of proteins expressed by a genome) and corresponding metabolism of the proto-mitochondrion by comparing extant alpha-proteobacterial and eukaryotic genomes. They concluded that this organism was an aerobic alpha-proteobacterium respiring lipids, glycerol and other compounds provided by the host. At least 630 gene families derived from this organism can still be found in the 9 eukaryotic genomes analyzed in the study.
See also
Abiogenesis
Endosymbiotic theory
Hydrogenosome
Midichloria
Protocell
Rickettsiales
References
Mitochondria
Pseudomonadota
Symbiosis
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https://en.wikipedia.org/wiki/Fibre%20Channel%20electrical%20interface
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The Fibre Channel electrical interface is one of two related Fibre Channel standards that can be used to physically interconnect computer devices. The other standard is a Fibre Channel optical interface, which is not covered in this article.
Fibre Channel signal characteristics
Fibre channel electrical signals are sent over a duplex differential interface. This usually consists of twisted-pair cables with a nominal impedance of 75 ohms (single-ended) or 150 ohms (differential). This is a genuine differential signalling system so no ground reference is carried through the cable, except for the shield. Signalling is AC-coupled, with the series capacitors located at the transmitter end of the link.
The definition of the Fibre Channel signalling voltage is complex. Eye-diagrams are defined for both the transmitter and receiver. There are many eye-diagram parameters which must all be met to be compliant with the standard. In simple terms, the transmitter circuit must output a signal with a minimum of 600 mV peak-to-peak differential, maximum 2000 mV peak-to-peak differential. A good signal looks rather like a sine-wave with a fundamental frequency of half the data rate, so 1 GHz for a typical system running at 2 gigabits per second.
The Bit-Error Rate (BER) objective for Fibre Channel systems is 1 in 1012 (1 bit in 1,000,000,000,000 bits). At 2 Gbit/s this equates to seven errors per hour. Therefore, this is a common event and the receiver circuitry must contain error-handling logic. In order to achieve such a low error-rate, jitter "budgets" are defined for the transmitter and cables.
Fibre Channel connector pinouts
There are various Fibre Channel connectors in use in the computer industry. Details of their pinouts are distributed between different official documents. The following sections describe the most common Fibre Channel pinouts with some comments about the purpose of their electrical signals.
The most familiar Fibre Channel connectors are
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https://en.wikipedia.org/wiki/Super%20Cars
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Super Cars is a top-view racing game from Gremlin Interactive, who later produced the Lotus series of games. Stylistically, the game is influenced by Super Sprint.
There are endless tracks at each of the 4 difficulty levels, which can be raced in any order (although the last track raced is made harder than usual). In the races the player wins money, which can be spent on temporary handling and power upgrades, plus armour plating and front/rear shooting missiles that can knock out other racers. The player must finish in the top 3 of each race to progress - initially there are 4 computer opponents, but more are added as the game progresses.
The car can be upgraded throughout the game via the shop section. The player is given an initial price, but also a number of options of things to say to the salesman - with the right combination, the price will drop.
The NES version was released exclusively in America in 1991 by Electro Brain.
It was followed by Super Cars II in 1991.
Cars
Three cars are available for purchase during the game, the Taraco Neoroder Turbo, the Vaug Interceptor Turbo and the Retron Parsec Turbo. Each appears to be based on a real car of the time with the Retron Parsec Turbo being based on the Cizeta-Moroder V16T, the Vaug Interceptor based on the Honda NSX and the Taraco Neoroder based on the Alfa Romeo SZ (Sprint Zagato) but with some slight changes. This is in slight contrast to the box art, where the blue "starter" car (Taraco) instead more closely resembles a contemporary European Ford Fiesta or Escort Cosworth convertible. The Retron is also portrayed differently on the box art, where it is a Lamborghini Countach instead of a Cizeta.
External links
Super Cars at MobyGames
References
1990 video games
Amiga games
Amstrad CPC games
Atari ST games
Commodore 64 games
Electro Brain games
Gremlin Interactive games
Magnetic Fields (video game developer) games
MSX games
Nintendo Entertainment System games
Single-player video games
Top-down raci
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https://en.wikipedia.org/wiki/Tundra%20orbit
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A Tundra orbit () is a highly elliptical geosynchronous orbit with a high inclination (approximately 63.4°), an orbital period of one sidereal day, and a typical eccentricity between 0.2 and 0.3. A satellite placed in this orbit spends most of its time over a chosen area of the Earth, a phenomenon known as apogee dwell, which makes them particularly well suited for communications satellites serving high-latitude regions. The ground track of a satellite in a Tundra orbit is a closed figure 8 with a smaller loop over either the northern or southern hemisphere. This differentiates them from Molniya orbits designed to service high-latitude regions, which have the same inclination but half the period and do not loiter over a single region.
Uses
Tundra and Molniya orbits are used to provide high-latitude users with higher elevation angles than a geostationary orbit. This is desirable as broadcasting to these latitudes from a geostationary orbit (above the Earth's equator) requires considerable power due to the low elevation angles, and the extra distance and atmospheric attenuation that comes with it. Sites located above 81° latitude are unable to view geocentric satellites at all, and as a rule of thumb, elevation angles of less than 10° can cause problems, depending on the communications frequency.
Highly elliptical orbits provide an alternative to geostationary ones, as they remain over their desired high-latitude regions for long periods of time at the apogee. Their convenience is mitigated by cost, however: two satellites are required to provide continuous coverage from a Tundra orbit (three from a Molniya orbit).
A ground station receiving data from a satellite constellation in a highly elliptical orbit must periodically switch between satellites and deal with varying signal strengths, latency and Doppler shifts as the satellite's range changes throughout its orbit. These changes are less pronounced for satellites in a Tundra orbit, given their increased distanc
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https://en.wikipedia.org/wiki/Compactness%20measure
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Compactness measure is a numerical quantity representing the degree to which a shape is compact. The circle and the sphere are the most compact planar and solid shapes, respectively.
Properties
Various compactness measures are used. However, these measures have the following in common:
They are applicable to all geometric shapes.
They are independent of scale and orientation.
They are dimensionless numbers.
They are not overly dependent on one or two extreme points in the shape.
They agree with intuitive notions of what makes a shape compact.
Examples
A common compactness measure is the isoperimetric quotient, the ratio of the area of the shape to the area of a circle (the most compact shape) having the same perimeter. In the plane, this is equivalent to the Polsby–Popper test. Alternatively, the shape's area could be compared to that of its bounding circle, its convex hull, or its minimum bounding box.
Similarly, a comparison can be made between the perimeter of the shape and that of its convex hull, its bounding circle, or a circle having the same area.
Other tests involve determining how much area overlaps with a circle of the same area or a reflection of the shape itself.
Compactness measures can be defined for three-dimensional shapes as well, typically as functions of volume and surface area. One example of a compactness measure is sphericity . Another measure in use is , which is proportional to .
For raster shapes, i.e. shapes composed of pixels or cells, some tests involve distinguishing between exterior and interior edges (or faces).
More sophisticated measures of compactness include calculating the shape's moment of inertia or boundary curvature.
Applications
A common use of compactness measures is in redistricting. The goal is to maximize the compactness of electoral districts, subject to other constraints, and thereby to avoid gerrymandering. Another use is in zoning, to regulate the manner in which land can be subdivided into building l
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https://en.wikipedia.org/wiki/Intermittency
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In dynamical systems, intermittency is the irregular alternation of phases of apparently periodic and chaotic dynamics (Pomeau–Manneville dynamics), or different forms of chaotic dynamics (crisis-induced intermittency).
Experimentally, intermittency appears as long periods of almost periodic behavior interrupted by chaotic behavior. As control variables change, the chaotic behavior become more frequent until the system is fully chaotic. This progression is known as the intermittency route to chaos.
Pomeau and Manneville described three routes to intermittency where a nearly periodic system shows irregularly spaced bursts of chaos. These (type I, II and III) correspond to the approach to a saddle-node bifurcation, a subcritical Hopf bifurcation, or an inverse period-doubling bifurcation. In the apparently periodic phases the behaviour is only nearly periodic, slowly drifting away from an unstable periodic orbit. Eventually the system gets far enough away from the periodic orbit to be affected by chaotic dynamics in the rest of the state space, until it gets close to the orbit again and returns to the nearly periodic behaviour. Since the time spent near the periodic orbit depends sensitively on how closely the system entered its vicinity (in turn determined by what happened during the chaotic period) the length of each phase is unpredictable.
Another kind, on-off intermittency, occurs when a previously transversally stable chaotic attractor with dimension less than the embedding space begins to lose stability. Near unstable orbits within the attractor orbits can escape into the surrounding space, producing a temporary burst before returning to the attractor.
In crisis-induced intermittency a chaotic attractor suffers a crisis, where two or more attractors cross the boundaries of each other's basin of attraction. As an orbit moves through the first attractor it can cross over the boundary and become attracted to the second attractor, where it will stay until its
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https://en.wikipedia.org/wiki/Mental%20Calculation%20World%20Cup
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The Mental Calculation World Cup (German: Weltmeisterschaften im Kopfrechnen, or World Championship in Mental Calculation) is an international competition for mental calculators, held every two years in Germany.
Mental Calculation World Cup 2004
The first Mental Calculation World Cup was held in Annaberg-Buchholz, Germany on 30 October 2004. There were 17 participants from 10 countries.
The World Cup involved the following contests (and two surprise tasks):
Adding ten 10-digit numbers, 10 tasks in 10 minutes
Winner: Alberto Coto (Spain); 10 correct results; 5:50 minutes, world record
Multiplying two 8-digit numbers, 10 tasks in 15 minutes
Winner: Alberto Coto (Spain), 8 correct results
Calendar Calculations, two series one minute each, dates from the years 1600–2100
Winner: Matthias Kesselschläger (Germany), 33 correct results, world record
Square Root from 6-digit numbers, 10 tasks in 15 minutes
Winner: Jan van Koningsveld (Germany)
In the overall ranking the first place is taken by Robert Fountain (Great Britain), the runner-up was Jan van Koningsveld (Germany).
Mental Calculation World Cup 2006
The second Mental Calculation World Cup was held on 4 November 2006 in the Mathematikum museum in Gießen, Germany.
26 Calculators from 11 countries took part.
The World Cup involved the following contests (and two surprise tasks):
Adding ten 10-digit numbers, 10 tasks in 10 minutes
Winner: Jorge Arturo Mendoza Huertas (Peru); 10 correct results
Multiplying two 8-digit numbers, 10 tasks in 15 minutes
Winner: Alberto Coto (Spain)
Calendar Calculations, two series one minute each, dates from the years 1600–2100
Winner: Matthias Kesselschläger (Germany)
Square Root from 6-digit numbers, 10 tasks in 15 minutes
Winner: Robert Fountain (Great Britain)
Robert Fountain (Great Britain) defended his title in the overall competition, the places 2 to 4 have been won by Jan van Koningsveld (Netherlands), Gert Mittring (Germany) and Yusnier Viera Romero (Cuba).
Mental Calculation
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https://en.wikipedia.org/wiki/KKOL%20%28AM%29
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KKOL (1300 kHz) is an AM radio station in Seattle, Washington. It is owned by Salem Media Group. It airs a conservative talk radio format, branded as "1300 The Answer," featuring nationally syndicated Salem Radio Network hosts including Dennis Prager, Mike Gallagher, Sebastian Gorka, Hugh Hewitt and Charlie Kirk. The radio studios and offices are on Fifth Avenue South. KKOL is the oldest radio station in Seattle, first licensed on May 23, 1922.
The transmitter site is on North Madison Avenue on Bainbridge Island, co-located with KLFE 1590 AM. By day, KKOL transmits 50,000 watts, the maximum for AM radio stations in the U.S., using a two-tower array directional antenna. At night it switches to non-directional operation, but to protect other stations on 1300 AM from interference, it reduces power to 3,200 watts.
History
KDZE
KKOL was first licensed, with the sequentially assigned call letters KDZE, on May 23, 1922. It was owned by the Rhodes Company Department Store at 1321 Second Avenue in Seattle. In the early days of broadcasting, some stations were owned by department stores and electronics stores, to promote the sale of receivers.
C. B. Williams, the department store's advertising manager, coordinated the installation of the initial 50-watt transmitter. The station's glass-enclosed studio was located on the second floor of the store, where shoppers could observe its operation.
At this time there was only a single wavelength, 360 meters (833 kHz) available for "entertainment" broadcasts, so KDZE was required to make a time-sharing agreement with the other stations already in operation. On June 23, Seattle stations were scheduled to operate from noon to 10:30 p.m., with KDZE assigned the 3:30 to 4:15 p.m time period.
In May 1923, the U.S. Commerce Department, which regulated radio at this time, made a range of frequencies available to "Class B" stations that had higher powers and better programming. The Seattle region was initially assigned 610 kHz, with 660
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https://en.wikipedia.org/wiki/Fib%20%28poetry%29
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Fib is an experimental Western poetry form, bearing similarities to haiku, but based on the Fibonacci sequence. That is, the typical fib and one version of the contemporary Western haiku both follow a strict structure. The typical fib is a six line, 20 syllable poem with a syllable count by line of 1/1/2/3/5/8 - with as many syllables per line as the line's corresponding place in the Fibonacci sequence; the specific form of contemporary Western haiku uses three (or fewer) lines of no more than 17 syllables in total. The only restriction on a Fib is that the syllable count follow the Fibonacci sequence. An example of a typical fib:
The form Pincus describes has had many poetic antecedents. John Frederick Nims discussed the concept and formal expressions of it as early as 1974, in his introduction to poetry, Western Wind. In 1981, The Figures Press published Ron Silliman's "Tjanting," in which Silliman adopts the number sequence to paragraph lengths. In her "Introduction" to The Penguin Book of the Sonnet, Editor Phillis Levin discusses ways in which the fibonacci number sequence is related to the development of the sonnet. Closer to Pincus's syllabic conception are Tony Leuzzi's three-stanza, 21-line poems, that follow a 1/1/2/3/5/8/13 structure and total 99 syllables. Marcia Birken and Anne C. Coon also discussed the fibonacci number sequence in their groundbreaking book, Discovering Patterns in Mathematics and Poetry. As Deborah Haar Clark has noted, "Fibonacci poetry is not new. It’s been around in one form or another for centuries, with works applying the numerical sequence to syllables, words, or letters." However, the six-line, 20-syllable fib itself was brought to wider public attention by Gregory K. Pincus on 1 April 2006. His blog has been the center of this new form of poetry. After Pincus published his blog on Fibs, they began appearing widely on the internet. Pincus wrote on his blog, "To my surprise (and joy), I continue to find new threads of
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https://en.wikipedia.org/wiki/Reliability-centered%20maintenance
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Reliability-centered maintenance (RCM) is a concept of maintenance planning to ensure that systems continue to do what their user require in their present operating context. Successful implementation of RCM will lead to increase in cost effectiveness, reliability, machine uptime, and a greater understanding of the level of risk that the organization is managing.
Context
It is generally used to achieve improvements in fields such as the establishment of safe minimum levels of maintenance, changes to operating procedures and strategies and the establishment of capital maintenance regimes and plans. Successful implementation of RCM will lead to increase in cost effectiveness, machine uptime, and a greater understanding of the level of risk that the organization is managing.
John Moubray characterized RCM as a process to establish the safe minimum levels of maintenance. This description echoed statements in the Nowlan and Heap report from United Airlines.
It is defined by the technical standard SAE JA1011, Evaluation Criteria for RCM Processes, which sets out the minimum criteria that any process should meet before it can be called RCM. This starts with the seven questions below, worked through in the order that they are listed:
1. What is the item supposed to do and its associated performance standards?
2. In what ways can it fail to provide the required functions?
3. What are the events that cause each failure?
4. What happens when each failure occurs?
5. In what way does each failure matter?
6. What systematic task can be performed proactively to prevent, or to diminish to a satisfactory degree, the consequences of the failure?
7. What must be done if a suitable preventive task cannot be found?
Reliability centered maintenance is an engineering framework that enables the definition of a complete maintenance regimen. It regards maintenance as the means to maintain the functions a user may require of machinery in a defined operating context. As a discipline it ena
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https://en.wikipedia.org/wiki/Active%20Format%20Description
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In television technology, Active Format Description (AFD) is a standard set of codes that can be sent in the MPEG video stream or in the baseband SDI video signal that carries information about their aspect ratio and other active picture characteristics. It has been used by television broadcasters to enable both 4:3 and 16:9 television sets to optimally present pictures transmitted in either format. It has also been used by broadcasters to dynamically control how down-conversion equipment formats widescreen 16:9 pictures for 4:3 displays.
Standard AFD codes provide information to video devices about where in the coded picture the active video is and also the "protected area" which is the area that needs to be shown. Outside the protected area, edges at the sides or the top can be removed without the viewer missing anything significant. Video decoders and display devices can then use this information, together with knowledge of the display shape and user preferences, to choose a presentation mode.
AFD can be used in the generation of Widescreen signaling, although MPEG alone contains enough information to generate this. AFDs are not part of the core MPEG standard; they were originally developed within the Digital TV Group in the UK and submitted to DVB as an extension, which has subsequently also been adopted by ATSC (with some changes). SMPTE has also adopted AFD for baseband SDI carriage as standard SMPTE 2016-1-2007, "Format for Active Format Description and Bar Data".
Active Format Description is occasionally incorrectly referred to as "Active Format Descriptor". There is no "descriptor" (descriptor has a specific meaning in ISO/IEC 13818-1, MPEG syntax). The AFD data is carried in the Video Layer of MPEG, ISO/IEC 13818-2. When carried in digital video, AFDs can be stored in the Video Index Information, in line 11 of the video.
By using AFDs broadcasters can also control the timing of Aspect Ratio switches more accurately than using MPEG signalling alone. T
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https://en.wikipedia.org/wiki/Atomic%20Energy%20Organization%20of%20Iran
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The Atomic Energy Organization of Iran (AEOI) is the main Iranian government agency responsible for operating nuclear energy and nuclear fuel cycle installations in Iran. AEOI is the primary organization responsible for nuclear technology research and development activities in Iran. AEOI was involved in formerly undeclared nuclear activities including enrichment facilities at Fordow and Natanz.
AEOI's headquarters are in the northern Amir Abad district in Tehran, but it has facilities throughout the country. The current head of AEOI is Mohammad Eslami, who replaced Ali Akbar Salehi on 29 August 2021. About 40% of Iranian scientists in the nuclear industry are women.
Nuclear Power Plans
AEOI Head Mohammed Eslami said in July 2023 that Iran planned to build nuclear power plants generating 20 GW in Khuzestan, Bushehr, Sistan, Hormozgan, and Baluchistan.
Schools
There are thirteen atomic energy highschools and primary elementary schools.
Research centers
Photonics and quantum technologies institute. formerly Laser research center created in 1976
Divisions
Nuclear Fuel Production Division (NFPD): Research and development on the nuclear fuel cycle, including uranium exploration, mining, milling, conversion, and nuclear waste management; departments include Jaber Ibn Hayan Research Dept., Exploration and Mining Dept., Benefication and Hydrometallurgical Research Center, Nuclear Fuel Research and Production Center, Waste Management Dept., and Saghand Mining Dept.
Nuclear Power Plant Division (NPPD): Responsible for planning, construction, commissioning, decommissioning and nuclear safety of nuclear power plants in Iran.
Engineering and Technical Supervision Department (ETSD): Design, review, evaluation and approval of engineering and technical documents, participation and quality control.
Research Division: Responsible for planning and guiding research projects; has eight affiliated research centers: Nuclear Research Center, Research Center for Lasers and thei
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https://en.wikipedia.org/wiki/List%20of%20PAN%20dating%20software
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PAN dating software is computer software to encourage conversation with others on a similar wireless network.
Bawadu
BlackPeopleMeet
Live Radar
MobiLuck
Nokia Sensor
Proxy Dating
See also
Lovegety
Toothing
References
Sexuality and computing
PAN dating software
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https://en.wikipedia.org/wiki/Flitch%20beam
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A flitch beam (or flitched beam) is a compound beam used in the construction of houses, decks, and other primarily wood-frame structures. Typically, the flitch beam is made up of a vertical steel plate sandwiched between two wood beams, the three layers being held together with bolts. In that common form it is sometimes referenced as a steel flitch beam. Further alternating layers of wood and steel can be used to produce an even stronger beam. The metal plates within the beam are known as flitch plates.[1] Flitch beams were used as a cost-effective way to strengthen long-span wooden beams, and have been largely supplanted by more recent technology.
History
"Flitch" originally referred to a slab of bacon, which was cut into strips lengthwise. Similarly, a wooden beam was flitched by cutting it lengthwise; one half was then rotated 180 degrees both longitudinally and laterally to ensure that any defects were separated. In the 18th century, before the availability of steel beams, pine beams were flitched with hardwood such as oak.
With the availability of affordable steel, flitch beams became a way to strengthen long-span wooden beams cost-effectively while taking up less space than solid wood. An 1883 article from The American Architect and Building News compares three alternatives in a hypothetical railway station "in which the second story is devoted to offices, and where we must use girders to support the second floor of 25-foot span, and not less than 12 feet on centres if we can avoid it. This would give us, to be supported by the girder, a floor area of 12’ x 25’ = 300 square feet" and 31,500 pounds of load. After performing calculations the beams compare as follows:
The article also cites the fire-retardant character of the flitch beam, “in case of a fire would not probably affect the iron until the wooden beams were badly burned.”
With the advent of high-strength engineered lumber, the advantages of flitch-beams disappeared. For example, comparing th
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https://en.wikipedia.org/wiki/Expressive%20power%20%28computer%20science%29
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In computer science, the expressive power (also called expressiveness or expressivity) of a language is the breadth of ideas that can be represented and communicated in that language. The more expressive a language is, the greater the variety and quantity of ideas it can be used to represent.
For example, the Web Ontology Language expression language profile (OWL2 EL) lacks ideas (such as negation) that can be expressed in OWL2 RL (rule language). OWL2 EL may therefore be said to have less expressive power than OWL2 RL. These restrictions allow for more efficient (polynomial time) reasoning in OWL2 EL than in OWL2 RL. So OWL2 EL trades some expressive power for more efficient reasoning (processing of the knowledge representation language).
Information description
The term expressive power may be used with a range of meaning. It may mean a measure of the ideas expressible in that language:
regardless of ease (theoretical expressivity)
concisely and readily (practical expressivity)
The first sense dominates in areas of mathematics and logic that deal with the formal description of languages and their meaning, such as formal language theory, mathematical logic and process algebra.
In informal discussions, the term often refers to the second sense, or to both. This is often the case when discussing programming languages. Efforts have been made to formalize these informal uses of the term.
The notion of expressive power is always relative to a particular kind of thing that the language in question can describe, and the term is normally used when comparing languages that describe the same kind of things, or at least comparable kinds of things.
The design of languages and formalisms involves a trade-off between expressive power and analyzability. The more a formalism can express, the harder it becomes to understand what instances of the formalism say. Decision problems become harder to answer or completely undecidable.
Examples
In formal language theory
For
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https://en.wikipedia.org/wiki/KZUP-CD
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KZUP-CD (channel 20) is a low-power, Class A independent television station in Baton Rouge, Louisiana, United States. It is owned by Nexstar Media Group alongside Fox affiliate WGMB-TV (channel 44) and CW owned-and-operated station WBRL-CD (channel 21); Nexstar also provides certain services to NBC affiliate WVLA-TV (channel 33) under joint sales and shared services agreements (JSA/SSA) with owner White Knight Broadcasting. The stations share studios on Perkins Road in Baton Rouge, while KZUP-CD's transmitter is located near Addis, Louisiana.
While "KZUP-CD" is the station's official call sign, it uses "KZUP-TV" for promotional purposes.
History
The station signed on the air in 1999 as a WZUP, a UPN affiliate available only on cable (TCI and later Cox channel 13). It was the second UPN affiliate (of three) in the Baton Rouge area. When the station went over the air on November 26, 2002, it changed its call sign to KZUP-CA; originally it was going to air on channel 21 and WB affiliate WBRL-CA was on channel 19, but this assignment was short-lived. Channel 19 was once used as a translator station for local station and original UPN affiliate WBTR, and when KZUP went on the air, WBTR moved to previously-unused channel 41. It became an independent station after losing UPN to Raycom Media's WBXH-CA in 2003. As an independent, it called itself "Z-19," and it primarily aired African-American-oriented programming like Good Times, The Fresh Prince of Bel-Air, and The Jeffersons. For brief periods in 2005, KZUP was used to simulcast WVLA and WGMB over analog as their individual transmitter towers were turned off to allow upgrades for their digital television channels. KZUP became an affiliate of the Retro Television Network on September 15, 2008. In 2012, White Knight Broadcasting dropped RTN and resumed carrying syndicated programming.
On April 24, 2013, Communications Corporation of America announced the sale of its entire group to Nexstar Broadcasting Group. WVLA and KZU
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https://en.wikipedia.org/wiki/Atomistix%20Virtual%20NanoLab
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Atomistix Virtual NanoLab (VNL) is a commercial point-and-click software for simulation and analysis of physical and chemical properties of nanoscale devices. Virtual NanoLab is developed and sold commercially by QuantumWise A/S. QuantumWise was then acquired by Synopsys in 2017.
Features
With its graphical interface, Virtual NanoLab provides a user-friendly approach to atomic-scale modeling. The software contains a set of interactive instruments that allows the user to design nanosystems, to set up and execute numerical calculations, and to visualize the results.
Samples such as molecules, nanotubes, crystalline systems, and two-probe systems (i.e. a nanostructure coupled to two electrodes) are built with a few mouse clicks.
Virtual NanoLab contains a 3D visualization tool, the Nanoscope, where atomic geometries and computed results can be viewed and analyzed. One can for example plot Bloch functions of nanotubes and crystals, molecular orbitals, electron densities, and effective potentials.
The numerical engine that carries out the actual simulations is Atomistix ToolKit, which combines density functional theory and non-equilibrium Green's functions to ab initio electronic-structure and transport calculations. Atomistix ToolKit is developed from the academic codes TranSIESTA and McDCal.
See also
Atomistix ToolKit
NanoLanguage
Atomistix
References
External links
QuantumWise web site
Nanotechnology companies
Computational science
Computational chemistry software
Physics software
Density functional theory software
Software that uses Qt
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https://en.wikipedia.org/wiki/Model-driven%20engineering
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Model-driven engineering (MDE) is a software development methodology that focuses on creating and exploiting domain models, which are conceptual models of all the topics related to a specific problem. Hence, it highlights and aims at abstract representations of the knowledge and activities that govern a particular application domain, rather than the computing (i.e. algorithmic) concepts.
MDE is a subfield of a software design approach referred as round-trip engineering. The scope of the MDE is much wider than that of the Model-driven architecture.
Overview
The MDE approach is meant to increase productivity by maximizing compatibility between systems (via reuse of standardized models), simplifying the process of design (via models of recurring design patterns in the application domain), and promoting communication between individuals and teams working on the system (via a standardization of the terminology and the best practices used in the application domain). For instance, in model-driven development, technical artifacts such as source code, documentation, tests, and more are generated algorithmically from a domain model.
A modeling paradigm for MDE is considered effective if its models make sense from the point of view of a user that is familiar with the domain, and if they can serve as a basis for implementing systems. The models are developed through extensive communication among product managers, designers, developers and users of the application domain. As the models approach completion, they enable the development of software and systems.
Some of the better known MDE initiatives are:
The Object Management Group (OMG) initiative Model-Driven Architecture (MDA) which is leveraged by several of their standards such as Meta-Object Facility, XMI, CWM, CORBA, Unified Modeling Language (to be more precise, the OMG currently promotes the use of a subset of UML called fUML together with its action language, ALF, for model-driven architecture; a former approach r
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https://en.wikipedia.org/wiki/ATLAS%20Transformation%20Language
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ATL (ATLAS Transformation Language) is a model transformation language and toolkit developed and maintained by OBEO and AtlanMod. It was initiated by the AtlanMod team (previously called ATLAS Group). In the field of Model-Driven Engineering (MDE), ATL provides ways to produce a set of target models from a set of source models.
Released under the terms of the Eclipse Public License, ATL is an M2M (Eclipse) component, inside of the Eclipse Modeling Project (EMP).
Overview
ATL is a model transformation language (MTL) developed by OBEO and INRIA to answer the QVT Request For Proposal. QVT is an Object Management Group standard for performing model transformations. It can be used to do syntactic or semantic translation. ATL is built on top of a model transformation Virtual Machine.
ATL is the ATLAS INRIA & LINA research group answer to the OMG MOF/QVT RFP. It is a model transformation language specified both as a metamodel and as a textual concrete syntax. It is a hybrid of declarative and imperative. The preferred style of transformation writing is declarative, which means simple mappings can be expressed simply. However, imperative constructs are provided so that some mappings too complex to be declaratively handled can still be specified.
An ATL transformation program is composed of rules that define how source model elements are matched and navigated to create and initialize the elements of the target models.
Architecture
A model-transformation-oriented virtual machine has been defined and implemented to provide execution support for ATL while maintaining a certain level of flexibility. As a matter of fact, ATL becomes executable simply because a specific transformation from its metamodel to the virtual machine bytecode exists. Extending ATL is therefore mainly a matter of specifying the new language features execution semantics in terms of simple instructions: basic actions on models (elements creations and properties assignments).
Example
An ATL program
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https://en.wikipedia.org/wiki/Power%20electronic%20substrate
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The role of the substrate in power electronics is to provide the interconnections to form an electric circuit (like a printed circuit board), and to cool the components. Compared to materials and techniques used in lower power microelectronics, these substrates must carry higher currents and provide a higher voltage isolation (up to several thousand volts). They also must operate over a wide temperature range (up to 150 or 200 °C).
Direct Bonded Copper (DBC) substrate
DBC substrates are commonly used in power modules, because of their very good thermal conductivity. They are composed of a ceramic material tile with a sheet of copper bonded to one or both sides by a high-temperature oxidation process (the copper and substrate are heated to a carefully controlled temperature in an atmosphere of nitrogen containing about 30 ppm of oxygen; under these conditions, a copper-oxygen eutectic forms which bonds successfully both to copper and the oxides used as substrates). The top copper layer can be preformed prior to firing or chemically etched using printed circuit board technology to form an electrical circuit, while the bottom copper layer is usually kept plain. The substrate is attached to a heat spreader by soldering the bottom copper layer to it.
A related technique uses a seed layer, photoimaging, and then additional copper plating to allow for fine lines (as small as 50 micrometres) and through-vias to connect front and back sides. This can be combined with polymer-based circuits to create high density substrates that eliminate the need for direct connection of power devices to heat sinks.
One of the main advantages of the DBC vs other power electronic substrates is their low coefficient of thermal expansion, which is close to that of silicon (compared to pure copper). This ensures good thermal cycling performances (up to 50,000 cycles). The DBC substrates also have excellent electrical insulation and good heat spreading characteristics.
Ceramic material used
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https://en.wikipedia.org/wiki/Carrier%20preselect
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Carrier preselect is a term relating to the telecommunications industry. It is a method of routing calls for least-cost routing (LCR) without the need for programming of PBX telephone system.
This is the process whereby a telephone subscriber whose telephone line is maintained by one company, usually a former monopoly provider (e.g. BT), can choose to have some of their calls automatically routed across a different telephone company's network (e.g. Talk Talk) without needing to enter a special code or special equipment.
See also
Local loop unbundling
Wholesale line rental
External links
Ofcom - Carrier Pre-Selection and Wholesale Line Rental
- Outbound Carrier Pre-Selection Services from GCI
- Outbound Carrier Pre-Selection Services from Six Degrees Group
Telephony
Local loop
Broadband
Telecommunications economics
Teletraffic
Telephone exchanges
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https://en.wikipedia.org/wiki/Need%20to%20know
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The term "need to know", when used by government and other organizations (particularly those related to the military or espionage), describes the restriction of data which is considered very sensitive. Under need-to-know restrictions, even if one has all the necessary official approvals (such as a security clearance) to access certain information, one would not be given access to such information, or read into a clandestine operation, unless one has a specific need to know; that is, access to the information must be necessary for one to conduct one's official duties. This term also includes anyone that the people with the knowledge deemed necessary to share it with.
As with most security mechanisms, the aim is to make it difficult for unauthorized access to occur, without inconveniencing legitimate access. Need-to-know also aims to discourage "browsing" of sensitive material by limiting access to the smallest possible number of people.
Examples
The Battle of Normandy in 1944 is an example of a need-to-know restriction. Though thousands of military personnel were involved in planning the invasion, only a small number of them knew the entire scope of the operation; the rest were only informed of data needed to complete a small part of the plan. The same is true of the Trinity project, the first test of a nuclear weapon in 1945.
Problems and criticism
Like other security measures, need to know can be misused by persons who wish to refuse others access to information they hold in an attempt to increase their personal power, prevent unwelcome review of their work, prevent embarrassment resulting from actions or thoughts.
Need to know can also be invoked to hide extra-legal activities. This may be considered a necessary use, or a detrimental abuse of such a policy when considered from different perspectives.
Need to know can be detrimental to workers' efficiency. Even when done in good faith, one might not be fully aware of who actually needs to know the informatio
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https://en.wikipedia.org/wiki/Effects%20loop
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An effects loop is a series of audio effects units, connected between two points of a signal path (the route that a signal would travel from the input to the output); usually between the pre-amp and power amp stages of an amplifier circuit, although occasionally between two pre-amp stages. The two principal uses of effects loops are in recordings and in instrument amplifiers.
There are two main advantages of an effects loop. The first is that generally effects sound clearer and are more pronounced when the input signal is sent through a preamplifier prior to being affected. In addition to this, the tone of a guitar amplifier is generally more defined if the guitar is going direct into the input of the preamplifier. The second advantage is to match impedances of equipment. For example, most guitar rack equipment works better at line-level, and not instrument level. By placing the effects after the preamp, signal loss due to impedance mismatch is avoided.
Most guitarists use floor pedal effects between the guitar and the amplifier, or they use rack effects through the amplifier effects loop. Some amplifier manufacturers have been including a level/gain control with the effects loops to allow for the use of floor pedals through the effects loop, rather than in-line between the guitar and amplifier. This allows for more tonal control of the amplifier.
See also
Effects unit
Audio amplifier
Guitar
Audio effects
Electrical signal connectors
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https://en.wikipedia.org/wiki/QVT
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QVT (Query/View/Transformation) is a standard set of languages for model transformation defined by the Object Management Group.
Overview
Model transformation is a key technique used in model-driven architecture. As the name QVT indicates, the OMG standard covers transformations, views and queries together. Model queries and model views can be seen as special kinds of model transformation, provided that we use a suitably broad definition of model transformation: a model transformation is a program which operates on models.
The QVT standard defines three model transformation languages. All of them operate on models which conform to Meta-Object Facility (MOF) 2.0 metamodels; the transformation states which metamodels are used. A transformation in any of the three QVT languages can itself be regarded as a model, conforming to one of the metamodels specified in the standard. The QVT standard integrates the OCL 2.0 standard and also extends it with imperative features.
QVT-Operational is an imperative language designed for writing unidirectional transformations.
QVT-Relations is a declarative language designed to permit both unidirectional and bidirectional model transformations to be written. A transformation embodies a consistency relation on sets of models. Consistency can be checked by executing the transformation in checkonly mode; the transformation then returns True if the set of models is consistent according to the transformation and False otherwise. The same transformation can be used in enforce mode to attempt to modify one of the models so that the set of models will be consistent. The QVT-Relations language has both a textual and a graphical concrete syntax.
QVT-Core is a declarative language designed to be simple and to act as the target of translation from QVT-Relations. However, QVT-Core has never had a full implementation and in fact it is not as expressive as QVT-Relations. Hence the QVT Architecture pictured above is misleading: the transformati
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https://en.wikipedia.org/wiki/Gainclone
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Gainclone or chipamp is a type of audio amplifier made by do-it-yourselfers, or individuals interested in DIY audio. It is a design based on high-power integrated circuits, particularly the National Semiconductor Overture series. The Gainclone is probably the most commonly built and well-known amplifier project amongst hobbyists. It is simple to build and involves only a few readily accessible, inexpensive parts. As an amplifier, it is highly regarded by many in the DIY community.
Background
In 1999, 47 Labs introduced the Gaincard amplifier. The Gaincard shook the audiophile community with its unconventional design. It had fewer parts, less capacitance, and simpler construction than virtually anything preceding it, and relied for amplification on a chip, the National Semiconductor LM3875. These construction techniques went against the accepted wisdom of the time, which favored large power supplies and discrete component construction. This Gaincard was estimated to cost less than in parts, but it sold for with its small power supply. Controversy ensued after a number of positive reviews.
Modern usage
The DIY community started building replicas or "clones" of the Gaincard using integrated circuits from National Semiconductor and other manufacturers in an attempt to see if good sound could be obtained, thereby the term: "gainclone". The name was first coined by a poster called "triodont" (Ramon Salamat) on the popular Audio Asylum board (ca. 1999;). "Triodont" tried to replicate the 47 Labs Gaincard amplifier for his own personal use and reported about it on the internet forum. Various modifications or improvements have been made to the original application circuit found in National's design notes since. The simple circuits were easy to make, and some started offering printed circuit boards and kits to make construction even easier.
The design concept has expanded and become rapidly more popular over the last few years as the simplicity of the design and avail
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https://en.wikipedia.org/wiki/INASP
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INASP (International Network for Advancing Science and Policy) is an international development charity working with a global network of partners to improve access, production and use of research information and knowledge, so that countries are equipped to solve their development challenges.
Based in Oxford and governed by an international Board of Trustees, INASP is run with a small number of full-time staff working with, and through, partners and networks in over one hundred countries. INASP's work is funded by its partner countries, governmental and non-governmental development agencies, and philanthropic foundations.
History
INASP original name, now superseded, was "International Network for the Availability of Scientific Publications".
It was established by the International Council for Science (ICSU) in 1992 to "improve access to information and knowledge through a commitment to capacity building in emerging and developing countries."
It was registered as a charity in 2004.
Work
INASP is an international development charity working with a global network of partners to improve access, production and use of research information and knowledge, so that countries are equipped to solve their development challenges
INASP has over 30 years of experience of working across research and knowledge systems in Africa, Latin America, and Asia. INASP believes that locally generated knowledge and solutions are key to solving local and global challenges. Their vision is of research and knowledge at the heart of development – where decisions are informed by relevant and rigorous evidence, and where knowledge is created with the communities it is intended to serve. Many voices, institutions, and types of knowledge are required.
INASP works in partnership with people and organisations who produce, communicate, and use knowledge to strengthen key capacities and confidence. Their work aims to support individuals with fewer opportunities, to reach beyond apex institutions,
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https://en.wikipedia.org/wiki/Arthur%20Rubin
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Arthur Leonard Rubin (born 1956) is an American mathematician and aerospace engineer. He was named a Putnam Fellow on four consecutive occasions from 1970 to 1973.
Life and career
Rubin's mother was Jean E. Rubin, a professor of mathematics at Purdue University, and his father was Herman Rubin, a professor of statistics at the same university. Arthur co-authored his first paper with his mother in 1969 at the age of 13. He earned his Ph.D. at the California Institute of Technology in 1978, under the direction of Alexander S. Kechris.
Rubin unsuccessfully stood as a Libertarian to represent the 55th district in the 1984 California State Assembly elections.
Awards and honors
As an undergraduate, Rubin was named a Putnam Fellow on four occasions, the first time in 1970, aged 14, making him the youngest Fellow to date. In 1972, he tied for third place in the first USA Mathematical Olympiad.
In 1974, Rubin was the subject of an article in the Madison Capital Times, in which his Caltech undergraduate advisor was quoted as saying that someone of Rubin's ability appeared in the United States "about once in every ten years".
Publications
Rubin's dissertation was entitled Free Algebras in Von Neumann–Bernays–Gödel Set Theory and Positive Elementary Inductions in Reasonable Structures. In 1979, Rubin co-authored a paper on list coloring of graphs with Paul Erdős, giving him an Erdős number of 1.
References
1956 births
Living people
20th-century American mathematicians
21st-century American mathematicians
American aerospace engineers
California Libertarians
California Institute of Technology alumni
Putnam Fellows
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https://en.wikipedia.org/wiki/Glue%20logic
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In electronics, glue logic is the custom logic circuitry used to interface a number of off-the-shelf integrated circuits. This is often achieved using common, inexpensive 7400- or 4000-series components. In more complex cases, a programmable logic device like a CPLD or FPGA might be used. The falling price of programmable logic devices, combined with their reduced size and power consumption compared to discrete components, is making them common even for simple systems. In addition, programmable logic can be used to hide the exact function of a circuit, in order to prevent a product from being cloned or counterfeited.
The software equivalent of glue logic is called glue code.
Usage
Typical functions of glue logic may include:
Simple logic functions.
Address decoding circuitry used with older processors like the MOS Technology 6502 or Zilog Z80 to divide up the processor's address space into RAM, ROM and I/O. Newer versions of these processors, such as the WDC 65816 or the Zilog eZ80, may add features that enable glueless interfacing to external devices.
Buffers to protect outputs from overload, or protect sensitive inputs from electrostatic discharge damage.
Voltage level conversion, e.g., when interfacing one logic family (CMOS) to another (TTL).
See also
Glue code
Reverse engineering
References
Electrical circuits
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https://en.wikipedia.org/wiki/CTIA%20%28organization%29
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CTIA is a trade association representing the wireless communications industry in the United States. The association was established in 1984 and is headquartered in Washington, D.C. It is a 501(c)(6) nonprofit membership organization, and represents wireless carriers and suppliers, and manufacturers and providers of wireless products and services.
CTIA operates certification programs for the wireless industry and publishes wireless industry surveys. It has also sponsored various public service initiatives related to wireless.
It was initially known as the Cellular Telecommunications Industry Association until 2004, and later the Cellular Telecommunications and Internet Association. The organization has since operated under its initialism only, subtitled as CTIA – The Wireless Association until 2015.
History
CTIA was established in May 1984 as the Cellular Telecommunications Industry Association. In 2000, the organization merged with the Wireless Data Forum and became the Cellular Telecommunications and Internet Association. Its name was changed to CTIA—The Wireless Association in 2004.
Tom Wheeler served as chief executive officer (CEO) of CTIA from 1992 to 2004. He was appointed chairman of the Federal Communications Commission (FCC) by President Barack Obama and confirmed by the United States Senate in November 2013.
Steve Largent became president and CEO in November 2003, serving until 2014. Meredith Attwell Baker became CTIA's president and CEO in June 2014.
Issue advocacy
Spectrum
When Baker was named president and CEO, she identified spectrum as a policy priority. She has testified before United States Congress on the issue. In a March 2016 media call, Baker said the industry is ready to invest billions of dollars to fund spectrum and new infrastructure. She suggested the "spectrum pipeline should become a national priority" because "100 MHz of spectrum is equal to $30 billion to the economy and 1 million jobs."
In 2016, CTIA released reports outlining
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https://en.wikipedia.org/wiki/List%20of%20Java%20virtual%20machines
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This article provides non-exhaustive lists of Java SE Java virtual machines (JVMs). It does not include every Java ME vendor. Note that Java EE runs on the standard Java SE JVM but that some vendors specialize in providing a modified JVM optimized for Java EE applications. Much Java development work takes place on Windows, Solaris, Linux, and FreeBSD, primarily with the Oracle JVMs. Note the further complication of different 32-bit/64-bit varieties.
The primary reference Java VM implementation is HotSpot, produced by Oracle Corporation and many other big and medium-sized companies (e.g. IBM, Redhat, Microsoft, Azul, SAP).
Free and open source implementations
Active
Codename One – uses the open source ParparVM
Eclipse OpenJ9 – open-source from IBM J9, for AIX, Linux (x86, Power, and Z), macOS, Windows, MVS, OS/400, Pocket PC, z/OS.
GraalVM – is based on HotSpot/OpenJDK, it has a polyglot feature, to transparently mix and match supported languages.
HotSpot – the open-source Java VM implementation by Oracle.
Jikes RVM (Jikes Research Virtual Machine) – research project. PPC and IA-32. Supports Apache Harmony and GNU Classpath libraries. Eclipse Public License.
leJOS – Robotics suite, a firmware replacement for Lego Mindstorms programmable bricks, provides a Java programming environment for the Lego Mindstorms RCX and NXT robots.
Maxine – meta-circular open source research VM from Oracle Labs and the University of Manchester.
Inactive
Apache Harmony – supports several architectures and systems. Discontinued November 2011. Apache License 2.0.
GCJ the GCC Java compiler, that compiles either to bytecode or to native machine code. As of GCC 7, gcj and associated libjava runtime library have been removed from GCC.
IKVM.NET – Java for Mono and the Microsoft .NET Framework. Uses OpenJDK. Zlib License.
JamVM – developed to be an extremely small virtual machine. Uses GNU Classpath and OpenJDK. Supports several architectures. GPL. Last update 2014.
JOP – hardwar
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https://en.wikipedia.org/wiki/Proper%20frame
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A proper frame, or comoving frame, is a frame of reference that is attached to an object. The object in this frame is stationary within the frame, which is useful for many types of calculations.
For example, a freely falling elevator is a proper frame for a free-falling object in the elevator, while the surface of the Earth is not. But, for an object on the Earth's surface, the Earth's surface is a proper frame while the falling elevator is not a proper frame. Proper frames can be inertial and non-inertial, as in the example above.
The use of a proper frame is essential for the investigation of physical laws within the framework of general relativity.
The term comoving frame is also a good description of a non-inertial frame, which is useful for many of the same uses as we mentioned previously. One advantage of proper frame and comoving frame is that the two frames must always maintain the same spatial position (i. "in the frame" - e.g. on the same frame of reference). This includes that the frame must always be in position in the spacetime frame and thus the spacetime can be viewed as having "no axis". As our first example of a proper frame, one uses the following frame to find the Earth:
The Earth is situated in the center with respect to the observer (or our point of reference) of our next example, the Sun is at the bottom.
𝜕 is described as the set of sets that have the property that the motion vectors of an object are conserved. 𝜕 can be thought of as the set of sets (including proper frames) of all possible motions of a given object, such that a proper frame always results.
In quantum field theory and many fields of physics, such as electromagnetism, it is often referred to as the "comoving frame" of a particle. 𝜕 can be thought of as the unique set of frames that are conserved under gravity, allowing that the particles of gravitation do not collapse on an object after the initial contact (for example, they remain in the frame they have been suspended in
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