omniomni/omni-engineering huggingface dataset:
AND gate. The AND gate is a basic digital logic gate that implements the logical conjunction (∧) from mathematical logic AND gates behave according to their truth table. A HIGH output (1) results only if all the inputs to the AND gate are HIGH (1). If all of the inputs to the AND gate are not HIGH, a LOW (0) is outputted. The function can be extended to any number of inputs by multiple gates up in a chain.

Symbols

There are three symbols for AND gates: the American (ANSI or 'military') symbol and the IEC ('European' or 'rectangular') symbol, as well as the deprecated DIN symbol. Additional inputs can be added as needed. For more information see the Logic gate symbols article. It can also be denoted as symbol "^" or "&".

The AND gate with inputs A and B and output C implements the logical expression . This expression also may be denoted as  or .

As of Unicode 16.0.0, the AND gate is also encoded in the Symbols for Legacy Computing Supplement block as .

Implementations

In logic families like TTL, NMOS, PMOS and CMOS, an AND gate is built from a NAND gate followed by an inverter. In the CMOS implementation above, transistors T1-T4 realize the NAND gate and transistors T5 and T6 the inverter.  The need for an inverter makes AND gates less efficient than NAND gates.

AND gates can also be made from discrete components and are readily available as integrated circuits in several different logic families.

Analytical representation 
 is the analytical representation of AND gate:

Alternatives 

If no specific AND gates are available, one can be made from NAND or NOR gates, because NAND and NOR gates are "universal gates"  meaning that they can be used to make all the others.

AND gates with multiple inputs 
AND gates with multiple inputs are designated with the same symbol, with more lines leading in.
While direct implementations with more than four inputs are possible in logic families like CMOS, these are inefficient. More efficient implementations use a cascade of NAND and NOR gates, as shown in the picture on the right below. This is more efficient than the cascade of AND gates shown on the left.

See also 

OR gate
NOT gate
NAND gate
NOR gate
XOR gate
XNOR gate
IMPLY gate
Boolean algebra
Logic gate

References 

Logic gates
Nanos. Nanos may refer to:

 Nanos (beetle), a genus in the tribe Canthonini
 Nanos (plateau), a plateau in the Dinaric Alps, Slovenia
 Nanos, Vipava, a settlement in the Municipality of Vipava, Slovenia
 Nanos Research, a Canadian polling firm
 nanos, a gene responsible for axis specification in a number of organisms such as in Drosophila embryogenesis
 Nanos, an illegitimate homonym genus for Nanum (bicosoecid)

People with the surname
 Apostolos Nanos, Olympic archer
 George Peter Nanos, former director of the Los Alamos National Laboratory
 Nikita Nanos, founder of Nanos Research
Marking out. Marking out or layout means the process of transferring a design or pattern to a workpiece, as the first step in the manufacturing process. It is performed in many industries or hobbies although in the repetition industries the machine's initial setup is designed to remove the need to mark out every individual piece.

Manufacturing

Marking out consists of transferring the dimensions from the plan to the workpiece in preparation for the next step, machining or manufacture.

Typical tools include:
 Surface plate or marking out table — provides a true surface from which to work
 Angle plates — assist in holding the workpiece perpendicular to the table
 Scriber — is the equivalent of a pen or pencil. It literally scratches the metal surface leaving behind a fine, bright line
 Height gauge or scribing block — allows lines to be scribed at a preset distance, from the tables surface
 Surface gauge — an ungraduated comparison measuring tool that performs much the same function as the vernier height gauge.  It is often used in conjunction with a dial indicator and a precision height gauge.
 Marking blue — to provide a usable writing surface by covering any existing scratches and providing a contrasting background
 Profile gauge
 Protractor — to assist in the transfer of angular measurements
 Combination square — an alternative tool for transferring angular measurements
 Square — to transfer 90° angles to the workpiece
 Punches — either prick or center punch to create permanent marks or dimples for drill bits to start in
 Automatic center punch — a spring-loaded punch that creates prick punch marks without the need for a ball peen hammer
 Ball peen hammer — used in conjunction with the punches to provide the striking blow needed
 Dividers or measuring compass — used for marking out circles of any desired radius,
 Parallels to aid in holding workpieces in specific positions and comparing measurements.

Welding
As welding does not always require the use of fine tolerances, marking out is usually performed by using centre punches, hammers, tape measures and chalk.

The "chalk" is actually a small pre-cut block of talc (soapstone). These talc blocks can be sharpened to a stronger point than the softer blackboard chalk. The color of the chalk provides good contrast against the dark color of the hot rolled steel that is generally used.

Woodworking

In carpentry and joinery practice a pencil is used for marking while in cabinetmaking a marking knife provides for greater accuracy. A storey pole is used to lay out repeated measurements such as the location of joints in timber framing, courses of siding such as wood shingles and clapboards, the heights of doorjambs and the courses of bricks in masonry. Carpenters typically mark out framing members on-center, the measurements are to the centers of each member.

References

Metalworking measuring instruments
Woodworking
Wilhelm Kress. Wilhelm Kress (29 July 1836 in Saint Petersburg – 24 February 1913 in Vienna) Born of German (Bavarian) parents in St. Petersburg in 1836. Moved to Vienna in 1873, where his self-propelled flying models attracted much attention. He became a naturalized Austrian.

Life 
Kress came to Vienna in 1873, where he developed the first modern delta-flying hang glider in 1877. This hang-glider was a major achievement for the time, when many engineers still struggled with the development of "heavier-than-air" non-powered aircraft. He also displayed rubber band powered flying models called the 'Aeroveloce' in 1877 and 1880. 

During the turn of the century he was one of the world-wide contestants for the creation of a break-through powered airplane. In 1900 he developed the control stick for aircraft, but did not apply for a patent (instead, a patent was awarded to the French aviator, Robert Esnault-Pelterie who applied for it in 1907). Kress' aircraft, the Drachenflieger, was constructed for water takeoff and achieved some brief hops in 1901 at the Wienerwaldsee near Vienna.

A longer controlled flight was not possible because the engine (made by Daimler) was twice as heavy as Kress had specified in his order, and could be operated only at half of its nominal power output.  During one of his attempts at flight taking off from water, his plane was destroyed when it became entangled on debris floating in the lake.

See also 
 Wright brothers
 Aviation
 List of Austrian scientists
 List of Austrians

References 
Aviation - The Pioneer Years

1836 births
1913 deaths
Aerospace engineers
Aviation inventors
Engineers from Austria-Hungary
Engineers from the Russian Empire
Emigrants from the Russian Empire to Austria-Hungary
German aviation pioneers
Tin can telephone. A tin can phone is a type of acoustic (non-electrical) speech-transmitting device made up of two tin cans, paper cups or similarly shaped items attached to either end of a taut string or wire.

It is a particular case of mechanical telephony, where sound (i.e., vibrations in the air) is converted into vibrations along a liquid or solid medium. These vibrations are transmitted through the medium (string) and then converted back to sound.

History 
Before the invention of the electromagnetic telephone, there were mechanical acoustic devices for transmitting spoken words and music over a greater distance, faster than the speed of sound in air. The very earliest mechanical telephones were based on transmission through pipes or other physical media, and among the very earliest experiments were those conducted by the British physicist and polymath Robert Hooke from 1664 to 1685. From 1664 to 1665 Hooke experimented with sound transmission through a taut extended wire. An acoustic string phone is attributed to him as early as 1667.

For a short period, acoustic telephones were marketed commercially as niche competitors to the electrical telephone, as they did not fall within the scope of its patent protection. When Alexander Graham Bell's telephone patent expired and dozens of new phone companies flooded the marketplace, acoustic telephone manufacturers could not compete and quickly went out of business. Their maximum range was very limited, but technical innovations (resulting in about 300 patents) increased their range to approximately , or more under ideal conditions. An example of one such company was Lemuel Mellett's 'Pulsion Telephone Supply Company' of Massachusetts, which designed its version in 1888 and deployed it on railroad rights-of-way, purportedly with a range of .

In the centuries before tin cans and paper cups became commonplace, other cups were used and the devices were sometimes called "lovers' telephones". During the 20th century, they came into common use in preschools and elementary schools to teach children about sound vibration.

Operation 

When the string is pulled taut and someone speaks into one of the cans, its bottom acts as a diaphragm, converting the sound waves into longitudinal mechanical vibrations which vary the tension of the string. These variations in tension set up longitudinal waves in the string which travel to the second can, causing its bottom to vibrate in a similar manner as the first can, thus recreating the sound, which is heard by the second person.

The signal can be directed around corners with at least two methods: The first is to create a loop in the string which is then twisted and anchored to another object. The second uses an extra can positioned on the apex of the corner; the string is threaded through the base of the can to avoid coming into contact with the object around which the signal is to be directed.

See also 
 History of the telephone
 Sound-powered telephone
 Speaking tube

References

External links 

 Tin Can Telephone
 How to Make a Tin Can Telephone

Traditional toys
Telephony equipment
RIVPACS. RIVPACS (River Invertebrate Prediction and Classification System) is an aquatic biomonitoring system for assessing water quality in freshwater rivers in the United Kingdom. It is based on the macroinvertebrate species (such as freshwater shrimp, freshwater sponges, worms, crayfish, aquatic snails, freshwater mussels, insects, and many others) found at the study site during sampling. Some of these species are tolerant to pollution, low dissolved oxygen, and other stressors, but others are sensitive; organisms vary in their tolerances. Therefore, different species will usually be found, in different proportions, at different river sites of varying quality. Some organisms are especially good indicator species. The species found at the reference sites collectively make up the species assemblage for that site and are the basis for a statistical comparison between reference sites and non-reference sites. The comparison between the expected species and the observed species can then be used to estimate this aspect of the ecological health of a river.

The system is meant to be standardized, easy to use, and relatively low cost. It can complement other types of water quality monitoring such as chemical monitoring. RIVPACS supports the implementation of the Water Framework Directive as its official tool for macroinvertebrate classification

Reference sites can be chosen and adjusted several ways. Usually they represent the best conditions within the region or area under study, and are a short stretch of river. Sometimes the reference site expectations are adjusted for degradation of the entire region by human impact. 'Pristine' freshwater sites are sampled to collect information on physical characteristics, chemistry, and macroinvertebrates, sometimes several times each year. This information is then used to predict what invertebrates are present from samples of physiochemistry from other sites.

RIVPACS is used across the UK and supported by Centre for Ecology and Hydrology, Countryside Council for Wales, Department for Environment, Food and Rural Affairs, Natural England, Environment Agency, Northern Ireland Environment Agency, Freshwater Biological Association, Scotland and Northern Ireland Forum for Environmental Research, Scottish Environment Protection Agency, Scottish Government, Scottish Natural Heritage, South West Water, and Welsh Assembly Government.

This classification of freshwater sites based on the macroinvertebrate fauna was first derived in 1977. Since then it has been developed and updated with addition of a wider range of freshwater sites. It has been adapted into various other versions around the world, including a Canadian version known as CABIN, AUSRIVAS in Australia, MEDPACS in Spain, and others.

External links
 RIVPACS - Centre for Ecology & Hydrology

References 

 John F. Wright, David W. Sutcliffe and Mike T. Furse. Assessing the biological quality of fresh waters: RIVPACS and other techniques. The Freshwater Biological Association, Ambleside, June 2000. 

Water pollution
Environmental science
Science and technology in the United Kingdom
Freshwater animals
Papier collé. Papier collé (French: pasted paper or paper cut outs) is a type of collage and collaging technique in which paper is adhered to a flat mount. The difference between collage and papier collé is that the latter refers exclusively to the use of paper, while the former may incorporate other two-dimension (non-paper) components. As the term papier collé is not commonly used, this type of work is often simply called collage.

Cubist painter Georges Braque, inspired by Pablo Picasso's collage method, invented the technique and first used it in his 1912 work, Fruit Dish and Glass. Braque continued to use the technique in works such as Bottle, Newspaper, Pipe, and Glass.

Papier collé is primarily used to refer specifically to the paper collages of the Cubists.

Notable collage artists 
Some of the notable collage artists are:

 Georges Braque
 Joseph Cornell
Juan Gris
 Henri Matisse
 Robert Motherwell
 Sergei Parajanov
 Pablo Picasso
 Robert Rauschenberg
 Kurt Schwitters
 Brian Clarke
 Kara Walker

References

Painting techniques
Cubism
Georges Braque
Henri Matisse
Paper art
Britannia metal. Britannia metal (also called britannium, Britannia ware, or Vickers White Metal) is a specific type of pewter alloy, favoured for its silvery appearance and smooth surface. The composition by weight is typically about 92–93% tin, 5–6% antimony, and 2% copper. Some sources use the terms "Britannia metal" and "britannium" to mean different things.

Britannia metal is usually spun rather than cast, and  melts at 255 degrees Celsius.

History

Britannia metal was first produced in 1769 or 1770. James Vickers created it after purchasing the formula from a dying friend. It was originally known as "Vickers White Metal" when made under contract by the Sheffield manufacturers Ebenezer Hancock and Richard Jessop. In 1776 James Vickers took over the manufacturing himself and remained as owner until his death in 1809, when the company passed to his son John and son-in-law Elijah West. In 1836 the company was sold to John Vickers's nephew Ebenezer Stacey (the son of Hannah Vickers and John Stacey).

After the development of electroplating with silver in 1846, Britannia metal was widely used as the base metal for silver-plated household goods and cutlery. The abbreviation EPBM on such items denotes "electroplated Britannia metal". Britannia metal was generally used as a cheaper alternative to electroplated nickel silver (EPNS) which is more durable.

For many years, britannia metal was used to make the solid core of the Oscar statuettes, which are 8½ lb (4 kg) and plated with 24-karat gold. For the first few years, they were gold-plated bronze, then later (perhaps starting in the 1930s, 1945, or 1982/1983; different sources disagree), they were made of britannia metal plated with copper then nickel silver then gold, except for three years during WWII, from 1942 to 1945, during which they were made of painted plaster due to metal shortages. Then starting with the 88th Academy Awards in 2016, they have returned to gold-plated bronze.

In his essay "A Nice Cup of Tea", writer George Orwell asserts that "britanniaware" teapots "produce inferior tea" when compared to chinaware.

See also

Britannia silver
English pewter (approximately 91% tin, 7.5% antimony and 1.5% copper)
Nickel silver ('German silver')
Reed & Barton

References

Fusible alloys
Tin alloys
Antimony alloys
Copper alloys
DnAnalytics. dnAnalytics was an open-source numerical library for .NET written in C# and F#. It featured functionality similar to BLAS and LAPACK. It was merged into Math.NET Numerics in 2009.

Features 
The software library provides facilities for:
 Linear algebra classes with support for sparse matrices and vectors (with an F# friendly interface).
 Dense and sparse solvers.
 Probability distributions.
 Random number generation (including Mersenne Twister MT19937).
 QR, LU, SVD, and Cholesky decomposition classes.
 Matrix IO classes that read and write matrices from/to Matlab, Matrix Market, and delimited files.
 Complex and “special” math routines.
 Descriptive Statistics, Histogram, and Pearson Correlation Coefficient.
 Overload mathematical operators to simplify complex expressions.
 Visual Studio visual debuggers for matrices and vectors
 Runs under Microsoft Windows and platforms that support Mono.
 Optional support for Intel Math Kernel Library (Microsoft Windows and Linux)

External links 

 Archived official site
 CodePlex archive

See also 
 Math.NET Numerics
 List of numerical libraries
 list of numerical analysis software

References 
Numerical software
Software using the BSD license
Mark 13 missile launcher. The Mark 13 guided missile launching system (GMLS) is a single-arm missile launcher designed for use on frigates and other military vessels. Because of its distinctive single-armed design, the Mark 13 is often referred to as the "one-armed bandit".

The Mark 13 is equipped to fire the RIM-66 Standard, RGM-84 Harpoon, and RIM-24 Tartar missiles for anti-air and anti-ship defense, and is capable of firing the Standard at a rate of one every eight seconds. Its 40-round magazine consists of two concentric rings of vertically stored missiles, 24 in the outer ring and 16 in the inner. Total capacity was reduced by 1 due to a requirement to carry a Guided Missile Training Round (GMTR) in order to test system functionality. In case of a fire, the system is equipped with magazine sprinkling, CO2 suppression and booster suppression. It is also equipped with a dud jettison function to eject a round overboard if it fails to fire.

Usage
In the United States Navy, the Mark 13 launcher was most typically employed as part of the Mark 74 Guided Missile Launch System, or the Mark 92 Fire Control System. Though the launcher was original armament on U.S. Navy Perry-class frigates (and their derivatives), in order to save costs on an obsolete system, by 2004 all active U.S. Navy vessels have had the system removed. It was also fitted on the French Cassard-class frigates, as well as the two Mitscher-class destroyers converted to DDGs, the last ten American Charles F. Adams-class destroyers, the American s, the German s and Australian s and s, and Dutch s and s, and Italian s.

Due to the end of the US Navy's support of the Mark 13 missile launcher, support for the systems in Taiwanese service was taken up by the National Chung-Shan Institute of Science and Technology. The same approach was taken for the Mark 13’s SM-1.

Variations
The Mark 22 guided missile launching system (GMLS) is a variation of the Mark 13 launcher which has only the inner 16 round storage ring of the Mark 13 launcher. It was deployed on US-designed, Baleares-class Spanish frigates. and US Navy Brooke class frigates. Another major difference is that on the Mark 22 the magazine is non-rotating. The launcher rotates over the desired missile and it is then hoisted onto the rail. On the Mark 13 the magazine rotates under the launcher.

Gallery

See also

List of United States Navy Guided Missile Launching Systems
Tartar Guided Missile Fire Control System
M-11 Shtorm Russian counterpart

References

External links
NAVEDTRA 14909 Gunner’s Mate 3 & 2 – Chapters 7 through 8 (1996) via alternatewars.com
FAS Mk 13 GMLS

Naval weapons of the United States
Naval guided missile launch systems of the United States
Military equipment introduced in the 1960s
Reference monitor. In operating systems architecture a reference monitor concept defines a set of design requirements on a reference validation mechanism, which enforces an access control policy over subjects' (e.g., processes and users) ability to perform operations (e.g., read and write) on objects (e.g., files and sockets) on a system. The properties of a reference monitor are captured by the acronym NEAT, which means:

 The reference validation mechanism must be Non-bypassable, so that an attacker cannot bypass the mechanism and violate the security policy.
 The reference validation mechanism must be Evaluable, i.e., amenable to analysis and tests, the completeness of which can be assured (verifiable). Without this property, the mechanism might be flawed in such a way that the security policy is not enforced.
 The reference validation mechanism must be Always invoked. Without this property, it is possible for the mechanism to not perform when intended, allowing an attacker to violate the security policy.
 The reference validation mechanism must be Tamper-proof. Without this property, an attacker can undermine the mechanism itself and hence violate the security policy.

For example, Windows 3.x and 9x operating systems were not built with a reference monitor, whereas the Windows NT line, which also includes Windows 2000 and Windows XP, was designed to contain a reference monitor, although it is not clear that its properties (tamperproof, etc.) have ever been independently verified, or what level of computer security it was intended to provide.

The claim is that a reference validation mechanism that satisfies the reference monitor concept will correctly enforce a system's access control policy, as it must be invoked to mediate all security-sensitive operations, must not be tampered with, and has undergone complete analysis and testing to verify correctness. The abstract model of a reference monitor has been widely applied to any type of system that needs to enforce access control and is considered to express the necessary and sufficient properties for any system making this security claim.

According to Ross Anderson, the reference monitor concept was introduced by James Anderson in an influential 1972 paper.  Peter Denning in a 2013 oral history stated that James Anderson credited the concept to a paper he and Scott Graham presented at a 1972 conference.

Systems evaluated at B3 and above by the Trusted Computer System Evaluation Criteria (TCSEC) must enforce the reference monitor concept.

References

See also
Security kernel

 Operating system security