omniomni/omni-engineering huggingface dataset:
Stateflow. Stateflow (developed by MathWorks) is a control logic tool used to model reactive systems via state machines and flow charts within a Simulink model.  Stateflow uses a variant of the finite-state machine notation established by David Harel, enabling the representation of hierarchy, parallelism and history within a state chart. Stateflow also provides state transition tables and truth tables.

Common uses
Stateflow is generally used to specify the discrete controller in the model of a hybrid system where the continuous dynamics (i.e., the behavior of the plant and environment) are specified using Simulink.

Specific applications for Stateflow include:
 Mode logic, where each discrete mode of a system is represented by a state
 Fault management, where the Stateflow chart is used to control how the system responds to faults and failures within a system
 Task scheduling, where the Stateflow chart is used to schedule when specific tasks occur, either within the Stateflow chart or within the overall Simulink model

Extensions
A number of MathWorks and third-party tools can be used with Stateflow to validate the design and generate code. For example, Simulink Verification and Validation, a MathWorks tool, can be used to check for requirements traceability and model coverage analysis. Other add-on code generation tools can be used to automatically generate C, C++, HDL, and PLC code for implementation on embedded systems.

References

Simulation programming languages
Visual programming languages
GHC. GHC may refer to:

Education
 Georgia Highlands College, in Rome, Georgia, US
 Global Health College, in Alexandria, Virginia, US
 Grays Harbor College, in Aberdeen, Washington, US
 Granada Hills Charter High School, in Granada Hills, California, US

Organisations
 Global Health Corps
 Global Health Council
 Group Health Cooperative
 Graham Holdings Company, an American conglomerate

Technology
 Glasgow Haskell Compiler, a compiler for the functional programming language Haskell
 Global Hybrid Cooperation, a set of vehicle technologies
 Grace Hopper Celebration of Women in Computing
 Guitar Hero Carabiner, a gaming device
 Guarded Horn clause, in concurrent logic programming

Other uses
 Guimarães Historic Centre, a UNESCO World Heritage Site
 Great Harbour Cay Airport (IATA airport code), in the Bahamas
 Hiberno-Scottish Gaelic, a language used in Ireland and Scotland from the 13th to the 18th century
 Global Honored Crown, the championships in the Japanese promotion Pro Wrestling Noah

See also

 Ghanaian cedi (currency sign: GH₵), the currency of Ghana
 WGHC (disambiguation), including WGHC callsign GHC in region W
Bob Boucher (educator). Robert Francis Boucher, CBE, FREng (25 April 1940 – 25 March 2009), usually known as Bob Boucher, was a British mechanical engineer, and Vice-Chancellor of both UMIST (1995–2001) the University of Sheffield (2001–2007).

Boucher was born in Wembley on 25 April 1940 and was educated at  St Ignatius' College, Stamford Hill, Borough Polytechnic, London, and gained a PhD from the University of Nottingham in Mechanical Engineering in 1966.   After postdoctoral work at the same university he moved to Queen's University Belfast as a researcher then a lecturer in mechanical engineering.

In 1970 he joined Sheffield University as a lecturer, rising to Head of the Department of Mechanical Engineering  in 1987 and Pro-Vice-Chancellor for Research at Sheffield.  In 1995 he took up the position of Vice-Chancellor and Principal of UMIST.  In 2001 he returned to Sheffield as Vice-Chancellor until his retirement in 2007. Boucher was Chairman of the International Sector Group of Universities UK and Treasurer of the Association of Commonwealth Universities.

Bob Boucher was appointed a CBE in 2000 "for services to Engineering Research, Industry and Education".
He died suddenly on 25 March 2009.

References
 BOUCHER, Prof, Robert Francis (Bob), Debrett's People of Today, 2007.

External links
 University of Sheffield release on Professor Boucher's death

1940 births
2009 deaths
People from Wembley
Academics of the University of Manchester Institute of Science and Technology
Academics of the University of Sheffield
Alumni of the University of Nottingham
Commanders of the Order of the British Empire
Fellows of the Royal Academy of Engineering
British mechanical engineers
Vice-chancellors of the University of Sheffield
Wing Commander (disambiguation). Wing commander is a senior commissioned rank in the British Royal Air Force and air forces of many countries which have historical British influence.

Wing Commander may also refer to:

Wing Commander (franchise), the Origin Systems computer game series and related franchise
Wing Commander (video game), the first title in the Wing Commander computer game series
Wing Commander (novel series), set in the game universe
Wing Commander (film), a 1999 film based on the computer game
 Wing Commander, a 1984 flight simulator game published by Mastertronic, not related to the Wing Commander franchise
Wing Commander (horse), a six-time World Grand Champion show horse
KCL. KCL or KCl may refer to:

Science and technology
 Potassium chloride (KCl), a metal halide salt
 Keycode lookup, keycode log, or keycode list
 Kirchhoff's current law, in physics
 Kyoto Common Lisp, an implementation of Common Lisp

Other uses
 King's College London, a public research university in London, UK and a constituent college of the University of London
+D. The +D (or Plus D) was a floppy disk and printer interface for the ZX Spectrum home computer. It was designed to be smaller and more reliable than its predecessor, the DISCiPLE, with fewer ports and steel casing to act as a heatsink. It saw little support from commercial software, but several games were compatible with +D hardware, notably games created by Zenobi Software. It was also used by AlchNews and Outlet, two magazines that covered electronics.

References

ZX Spectrum
Receptor potential. A receptor potential, also known as a  generator potential, a type of graded potential, is the transmembrane potential difference produced by activation of a sensory receptor.

A receptor potential is often produced by sensory transduction. It is generally a depolarizing event resulting from inward current flow. The influx of current will often bring the membrane potential of the sensory receptor towards the threshold for triggering an action potential. Receptor potential can work to trigger an action potential either within the same neuron or on an adjacent cell. Within the same neuron, a receptor potential can cause local current to flow to a region capable of generating an action potential by opening  voltage-gated ion channels. A receptor potential can also cause the release of neurotransmitters from one cell that will act on another cell, generating an action potential in the second cell. The magnitude of the receptor potential determines the frequency with which action potentials are generated and is controlled by adaptation, stimulus strength, and temporal summation of successive receptor potentials. Receptor potential relies on receptor sensitivity which can adapt slowly, resulting in a slowly decaying receptor potential or rapidly, resulting in a quickly generated but shorter-lasting receptor potential.

An example of a receptor potential is in a taste bud, where taste is converted into an electrical signal sent to the brain.  When stimulated, the taste bud triggers the release of neurotransmitters through exocytosis of synaptic vesicles from the presynaptic membrane. The neurotransmitter molecules diffuse across the synaptic cleft to the postsynaptic membrane of the primary sensory neuron, where they elicit an action potential.

See also
Resting potential
Action potential

References

Receptors
Electrophysiology
Graded potentials
Barrel of oil equivalent. The barrel of oil equivalent (BOE) is a unit of energy based on the approximate energy released by burning one barrel (,  or about ) of crude oil. The BOE is used by oil and gas companies in their financial statements as a way of combining oil and natural gas reserves and production into a single measure, although this energy equivalence does not take into account the lower financial value of energy in the form of gas.

The U.S. Energy Information Administration defines the barrel of oil equivalent as about . The value is necessarily approximate as various grades of oil and gas have slightly different heating values. If one considers the lower heating value instead of the higher heating value, the value for one BOE would be approximately 5.4 GJ (see tonne of oil equivalent). Typically  is equivalent to one BOE. The United States Geological Survey gives a figure of  of typical natural gas.

Due to the risk of confusion The Society of Petroleum Engineers recommends in their style guide that abbreviations or prefixes M or MM are not used for barrels of oil or barrel of oil equivalent, but rather that thousands, millions or billions are spelled out. Common prefixes for readers familiar with the metric system are k for thousand, M for million and G for billion while other readers might be more familiar with M for thousand, MM for million and B for billion. All those multiples are commonly combined with barrel of oil equivalent from the level of individual production units output per day to level of petroleum reserves.

Metric regions commonly use the tonne of oil equivalent (toe), or more often million toe (Mtoe). Since this is a measurement of mass, any conversion to barrels of oil equivalent depends on the density of the oil in question, as well as the energy content. Typically 1 tonne of oil has a volume of . The United States EIA suggests 1 toe has an average energy value of .

See also

References

Petroleum economics
Units of energy
Equivalent units
Beechcraft XA-38 Grizzly. The Beechcraft XA-38 "Grizzly" was a World War II-era ground attack aircraft, developed by Beechcraft, but never put into production. The Grizzly was to have been fitted with a forward-firing 75 mm cannon to penetrate heavily armored targets.

While the first prototype flew on 7 May 1944, testing established that the type would not be ready for the projected invasion of Japan. It also featured the Wright R-3350 engines already in use with the Boeing B-29 Superfortress—which had priority. Consequently, the XA-38 was canceled after a second prototype had been completed.

Design and development
The United States Army Air Forces awarded the Beech Aircraft Corporation a contract in December 1942 for two prototypes for their Model 28 "Destroyer".  to give a powerful ground attack aircraft to replace the Douglas A-20 Havoc, with the ability to hit "hardened" targets like tanks and bunkers and to attack coastal shipping. This capability was achieved through a 75 mm cannon with 20 rounds, mounted in a fixed position on the nose as well as two .50 cal (12.7 mm) M2 Browning machine guns firing forward. Defensive armament consisted of remotely controlled ventral and dorsal turrets, each armed with twin .50 cal (12.7 mm) machine guns. There were to be two crew members, a pilot and an observer/gunner in the rear cabin, using periscope sights to aim the guns.

Testing
On 7 May 1944, Beech test pilot Vern Carstens flew the XA-38 on its maiden flight from the company's Wichita airfield. The aircraft proved satisfactory in all respects and better than expected in some, including top speed.

During testing, the XA-38 prototypes were flown by USAAF pilots and serviced by military personnel, proving to be reliable and establishing a high level of serviceability.

The armament proved especially effective; if not for a shift in wartime priorities in 1944, the aircraft would most likely have been ordered in quantity even though the B-29 had priority for the Wright R-3350 engines. Instead, one prototype was scrapped and the other, intended for the USAF Museum, had an unknown fate.

Specifications

See also

References

Further reading

External links

 USAF Museum: XA-38 Grizzly

A-038
Beechcraft A-38 Grizzly
Cancelled military aircraft projects of the United States
Aircraft first flown in 1944
Mid-wing aircraft
Twin piston-engined tractor aircraft
Aircraft with retractable conventional landing gear
Twin-tail aircraft
Tupolev Tu-80. The Tupolev Tu-80 () was a Soviet prototype for a longer-ranged version of the Tupolev Tu-4 bomber, an unlicensed, reverse engineered copy of the Boeing B-29 Superfortress. It was cancelled in 1949 in favor of the Tupolev Tu-85 program which offered even more range. The sole prototype was used in various test programs before finally being used as a target.

Development
The Tu-80 was designed as a modernized and enlarged Tu-4 with greater range. This was to be achieved by the use of more fuel-efficient engines, better aerodynamics and added fuel tanks. It was intended to have a range of  and carry a maximum bombload of  with a top speed of . Work began on the design in February 1948 and this was confirmed by a Council of Ministers order of 12 June that required the prototype be ready for State acceptance trials in July 1949.

The forward portion of the fuselage was redesigned with an airliner-style stepped windscreen and the fuselage was lengthened by almost  which allowed the bomb bays and their doors to be lengthened. The radar and its operator were moved into the forward pressurized compartment and the radar itself was located in the "chin" position in a new streamlined fairing. The wings were enlarged to a total of  and the rubber deicing boots were replaced by more efficient and aerodynamic bleed air deicers. The engine nacelles were redesigned with smaller cross-sections with less drag. Originally, Shvetsov ASh-2TK or Dobrynin VD-3TK engines were considered, but neither engine was ready so the Shvetsov ASh-73TKFN was used. Fully feathering propellers were also used. All of these changes increased the lift/drag ratio to 18 from the 17.0 of the Tu-4.

Construction of the Tu-80 began in November 1948, using as many Tu-4 components as possible to speed up construction, but the first flight was not until 1 December 1949, after the Council of Ministers had canceled the program on 16 September 1949 in favor of the Tu-85 which was expected to have much better performance. The Tu-80 became a research aircraft, testing reversible-pitch propellers and structural deformation in heavy aircraft, before eventually became a target on a bombing and gunnery range.

Specifications

See also

References

Bibliography
 
 
 

Tu-0080
1940s Soviet bomber aircraft
Abandoned military aircraft projects of the Soviet Union
Soviet Union–United States relations
Four-engined tractor aircraft
Tu-80
Mid-wing aircraft
Aircraft first flown in 1949
Four-engined piston aircraft
Tupolev Tu-75. The Tupolev Tu-75 () was a military transport variant of the Tu-4 bomber, an unlicensed, reverse engineered copy of the Boeing B-29 Superfortress. The Tu-75 was similar to the Tu-70 airliner, both using a new, purpose-designed fuselage. The first Soviet military machine of this class, it was equipped with a rear fuselage loading ramp. It was not placed into production because the VVS decided it would be cheaper to modify its existing Tu-4s for the transport mission and to use its existing Lisunov Li-2 and Ilyushin Il-12 transports.

Design and development
The Tupolev OKB began work in September 1946 on a military transport version of the Tupolev Tu-70 airliner and this was confirmed by the Council of Ministers on 11 March 1947 with state trials to begin in August 1948. To expedite the process, maximum use was made of components of the Tu-70. Its engines were the uprated Shvetsov ASh-73TKFN or TKNV fuel-injected version. A new, narrower fuselage was designed, which included a rear cargo hatch, a vehicle loading ramp and paratroop exit doors. Three gun turrets (dorsal, ventral and tail), were to be adapted from the Tu-4, although they were not fitted on the prototype. It had a crew of six (two pilots, three gunners, a radio operator, and a navigator).

The aircraft was intended for three different roles; transport, parachute transport and aerial ambulance. In the first role it was designed to carry two ASU-76 assault guns, two STZ NATI artillery tractors, six or seven GAZ-67B jeeps or five  guns without their prime movers or any combination of equipment up to . To facilitate the loading of cargo, a winch was mounted on the ceiling of the cargo hold with a capacity of . It could carry either 120 troops, 96 fully loaded paratroopers or 64 standard parachute loads. As an aerial ambulance it could carry 31 stretchers and four medical attendants.

Operational history
Construction of the first prototype was quite prolonged; the aircraft was not finished until November 1949, with its first flight taking place on 21 January 1950. It finished its manufacturer's trials the following May, but Tupolev decided not to submit it for the State acceptance trials as the Soviet Air Force had already decided that it would be cheaper to rely on its existing transports and to modify Tu-4 bombers for the cargo role. The prototype was used by the MAP ( – Ministry of Aviation Industry) until it crashed in October 1954.

Specifications

See also

References

Notes

Bibliography
 
 
 

Tu-0075
1950s Soviet military transport aircraft
Four-engined tractor aircraft
Low-wing aircraft
Abandoned military aircraft projects of the Soviet Union
Tu-75
Aircraft first flown in 1950
Four-engined piston aircraft
Tupolev Tu-72. The Tupolev Tu-72 was a proposed Soviet medium bomber of the late 1940s. It was based on the Tupolev Tu-8, but differed by having a slightly longer fuselage, increased defensive armament, and slightly enlarged vertical stabilizers. The first flight of the Tu-72 was scheduled for 1948, but the project was cancelled due to the success of the Tupolev Tu-4 and Tupolev's focus on first-generation strategic jet bombers.

References

Tu-0072
1940s Soviet bomber aircraft
Graph reduction. In computer science, graph reduction implements an efficient version of non-strict evaluation, an evaluation strategy where the arguments to a function are not immediately evaluated. This form of non-strict evaluation is also known as lazy evaluation and used in functional programming languages. The technique was first developed by Chris Wadsworth in 1971.

Motivation 
A simple example of evaluating an arithmetic expression follows:

The above reduction sequence employs a strategy known as outermost tree reduction. The same expression can be evaluated using innermost tree reduction, yielding the reduction sequence:

Notice that the reduction order is made explicit by the addition of parentheses. This expression could also have been simply evaluated right to left, because addition is an associative operation.

Represented as a tree, the expression above looks like this:

This is where the term tree reduction comes from.  When represented as a tree, we can think of innermost reduction as working from the bottom up, while outermost works from the top down.

The expression can also be represented as a directed acyclic graph, allowing sub-expressions to be shared:

As for trees, outermost and innermost reduction also applies to graphs.  Hence we have graph reduction.

Now evaluation with outermost graph reduction can proceed as follows:

Notice that evaluation now only requires four steps. Outermost graph reduction is referred to as lazy evaluation and innermost graph reduction is referred to as eager evaluation.

Combinator graph reduction 
Combinator graph reduction is a fundamental implementation technique for functional programming languages, in which a program is converted into a combinator representation which is mapped to a directed graph data structure in computer memory, and program execution then consists of rewriting parts of this graph ("reducing" it) so as to move towards useful results.

History 
The concept of a graph reduction that allows evaluated values to be shared was first developed by Chris Wadsworth in his 1971 Ph.D. dissertation. This dissertation was cited by Peter Henderson and James H. Morris Jr. in 1976 paper, “A lazy evaluator” that introduced the notion of lazy evaluation. In 1976 David Turner incorporated lazy evaluation into SASL using combinators.
SASL was an early functional programming language first developed by Turner in 1972.

See also
Graph reduction machine
SECD machine

Notes

References

Further reading

Implementation of functional programming languages
Graph algorithms
Graph rewriting
Catalan solid. The Catalan solids are the dual polyhedra of Archimedean solids. The Archimedean solids are thirteen highly-symmetric polyhedra with regular faces and symmetric vertices. The faces of the Catalan solids correspond by duality to the vertices of  by Archimedean solids, and vice versa. One way to construct the Catalan solids is by using the Dorman Luke construction.

The Catalan solids are face-transitive or isohedral meaning that their faces are symmetric to one another, but they are not vertex-transitive because their vertices are not symmetric. Their dual, the Archimedean solids, are vertex-transitive but not face-transitive. Each Catalan solid has constant dihedral angles, meaning the angle between any two adjacent faces is the same. Additionally, two Catalan solids, the rhombic dodecahedron and rhombic triacontahedron, are edge-transitive, meaning their edges are symmetric to each other. Some Catalan solids were discovered by Johannes Kepler during his study of zonohedra, and Eugene Catalan completed the list of the thirteen solids in 1865. 

Two Catalan solids, the pentagonal icositetrahedron and the pentagonal hexecontahedron, are chiral, meaning that these two solids are not their own mirror images. They are dual to the snub cube and snub dodecahedron respectively, which are also chiral.

Eleven of the thirteen Catalan solids are known to have the Rupert property that a copy of the same solid can be passed through a hole in the solid.

References

Footnotes

Works cited 
 .
 .
 .
 .
 
 
  (Section 3-9)

External links

 
 
 Catalan Solids – at Visual Polyhedra
 Archimedean duals – at Virtual Reality Polyhedra
 Interactive Catalan Solid in Java
 Download link for Catalan's original 1865 publication – with beautiful figures, PDF format

Polyhedra
Discrete system. In  theoretical computer science, a discrete system is a system with a countable number of states. Discrete systems may be contrasted with continuous systems, which may also be called analog systems. A final discrete system is often modeled with a directed graph and is analyzed for correctness and complexity according to computational theory. Because discrete systems have a countable number of states, they may be described in precise mathematical models.

A computer is a finite-state machine that may be viewed as a discrete system. Because computers are often used to model not only other discrete systems but continuous systems as well, methods have been developed to represent real-world continuous systems as discrete systems. One such method involves sampling a continuous signal at discrete time intervals.

See also
Digital control
Finite-state machine
Frequency spectrum
Mathematical model
Sample and hold
Sample rate
Sample time
Z-transform

References

Automata (computation)
Models of computation
Signal processing
Sawfish harvester. The Sawfish harvester is a submersible robot produced by the Triton Logging Inc.  It is designed for cutting down  submerged trees and popping them to the surface, with large pincers and a chainsaw.  Such trees are generally submerged when dams are built near existing forests, and their wood remains good while underwater for long periods.

External links
 News report on the Sawfish
 Triton Engineering page: details on the Sawfish

Underwater robots
2000s robots
Robots of Canada