omniomni/omni-engineering huggingface dataset:
Proof-carrying code. Proof-carrying code (PCC) is a software mechanism that allows a host system to verify properties about an application via a formal proof that accompanies the application's executable code.  The host system can quickly verify the validity of the proof, and it can compare the conclusions of the proof to its own security policy to determine whether the application is safe to execute.  This can be particularly useful in ensuring memory safety (i.e. preventing issues like buffer overflows).

Proof-carrying code was originally described in 1996 by George Necula and Peter Lee.

Packet filter example
The original publication on proof-carrying code in 1996 used packet filters as an example: a user-mode application hands a function written in machine code to the kernel that determines whether or not an application is interested in processing a particular network packet. Because the packet filter runs in kernel mode, it could compromise the integrity of the system if it contains malicious code that writes to kernel data structures. Traditional approaches to this problem include interpreting a domain-specific language for packet filtering, inserting checks on each memory access (software fault isolation), and writing the filter in a high-level language which is compiled by the kernel before it is run. These approaches have performance disadvantages for code as frequently run as a packet filter, except for the in-kernel compilation approach, which only compiles the code when it is loaded, not every time it is executed.

With proof-carrying code, the kernel publishes a security policy specifying properties that any packet filter must obey: for example, the packet filter will not access memory outside of the packet and its scratch memory area. A theorem prover is used to show that the machine code satisfies this policy. The steps of this proof are recorded and attached to the machine code which is given to the kernel program loader. The program loader can then rapidly validate the proof, allowing it to thereafter run the machine code without any additional checks. If a malicious party modifies either the machine code or the proof, the resulting proof-carrying code is either invalid or harmless (still satisfies the security policy).

See also
 Typed assembly language
 Program derivation
 Formal verification
 Berkeley Packet Filter

References

 George C. Necula and Peter Lee. Proof-Carrying Code.  Technical Report CMU-CS-96-165, November 1996. (62 pages)
 George C. Necula and Peter Lee.  Safe, Untrusted Agents Using Proof-Carrying Code.  Mobile Agents and Security, Giovanni Vigna (Ed.), Lecture Notes in Computer Science, Vol. 1419, Springer-Verlag, Berlin, , 1998.
 George C. Necula. Compiling with Proofs. PhD thesis, School of Computer Science, Carnegie Mellon Univ., Sept. 1998.
Dependently typed programming
Formal methods
Programming language theory
Cybersecurity engineering
Westell. Westell Technologies, Inc. is an Aurora, Illinois company that provides telecommunications equipment for in-building wireless, intelligent site management, cell site optimization, and outside plant solutions. Westell was the last company to manufacture DSL modems in the United States; however, on May 21, 2007, Westell announced plans to outsource manufacturing.

History
Westell was founded in October 1980 in Willowbrook, Illinois, and initially produced electronic equipment used for signaling and transmission on telephone lines leased to private customers. 
Clinton Penny, who had previously founded Wescom Switching, founded Westell.
Beginning in 1992, Westell began developing ADSL products.  By the time of its initial public offering (IPO) in 1995, Westell was a prominent DSLAM manufacturer.  The company moved out of this business in the wake of the stock market downturn of 2002, and then focused primarily on manufacturing cell site optimization equipment, Ethernet connectivity products, intelligent site management and a series of outdoor enclosure and cabinets.

In 2013, Westell acquired Kentrox Inc., a Dublin-based site management services company, for $30 million.

References

Telecommunications companies of the United States
Telecommunications equipment vendors
Telecommunications companies established in 1980
Economy of Aurora, Illinois
Companies based in DuPage County, Illinois
Companies formerly listed on the Nasdaq
1995 initial public offerings
Cheong Liew. Cheong Liew  (born 1949) is a Malaysian-born Australian chef. He moved from Malaysia to Australia in 1969 to study electrical engineering, but instead became a chef. Famous for experimentation with new ingredients and formats, Liew has also been important in the development of Asian-Australian fusion cuisine.

Early life
Cheong Liew was born in 1949 in Kuala Lumpur, Malaysia. His father was a farmer who also owned several restaurants. Following the 13 May incident, Liew's family emigrated to Adelaide, South Australia. In Adelaide, Liew's passion for cooking was ignited while he tended the grill part-time at the Greek restaurant Iliad in Whitmore Square. Although he had planned to study electrical engineering in Melbourne, he eventually decided to become a self-taught chef.

Career
In 1975, Liew opened his own restaurant Neddy's, whose menu consisted of mostly Malaysian and Chinese dishes. His cooking incorporated ingredients not commonly used during his time, such as crocodile tail, pork leg, sea urchin and shark lip. The restaurant closed in 1988 and Liew went on to teach cookery at Regency Park, Adelaide.

In 1995, Liew took the reins at The Grange restaurant at the Hilton Hotel in Adelaide. At The Grange, Liew came up his "signature dish", titled "Four Dancers of the Sea", featuring "four varieties of seafood cooked in four distinct national styles". In 2009, after some 14 years, Cheong left The Grange; the restaurant closed at the end of the year.

Awards and honours
Described as "one of the indisputable fathers of Australian cooking" by Stephen Downes in To Die For (2006), Liew was awarded the Medal of the Order of Australia in the 1999 Queen's Birthday Honours "for service to the food and restaurant industry through involvement in developing and influencing the style of contemporary Australian cuisine. In 2017, Liew was honoured as "one of the ten hottest chefs alive" by the American publication Food & Wine Magazine, and inducted into the Hall of Fame in the World Food Media Awards.

Writing
 Liew, C., & Ho, E. F. (1995). My Food. St Leonards, N.S.W., Allen & Unwin.

References

See also
 South Australian food and drink

People from Adelaide
Living people
People from Kuala Lumpur
Australian chefs
Recipients of the Medal of the Order of Australia
Malaysian emigrants to Australia
1949 births
Triphenylmethanol. Triphenylmethanol (also known as triphenylcarbinol and TrOH) is an organic compound.  It is a white crystalline solid that is insoluble in water and petroleum ether, but well soluble in ethanol, diethyl ether, and benzene. In strongly acidic solutions, it produces an intensely yellow color, due to the formation of a stable "trityl" carbocation. Many derivatives of triphenylmethanol are important dyes.

History 
After the German chemist August Kekulé and his Belgian student Antoine Paul Nicolas Franchimont (1844–1919) first synthesized triphenylmethane in 1872, the Russian doctoral student Walerius Hemilian (1851–1914) first synthesized triphenylmethanol in 1874 by reacting triphenylmethyl bromide with water as well as by oxidizing triphenylmethane.

Structure and properties
Triphenylmethanol features three phenyl (Ph) rings and an alcohol group bound to a central tetrahedral carbon atom. All three C–Ph bonds are typical of sp3-sp2 carbon-carbon bonds with lengths of approximately 1.47 Å, while the C–O bond length is approximately 1.42 Å.

The presence of three adjacent phenyl groups confers special properties manifested in the reactivity of the alcohol.  For example it reacts with acetyl chloride, not to give the ester, but triphenylmethyl chloride:
Ph3COH + MeCOCl → Ph3CCl + MeCO2H

The three phenyl groups also offer steric protection. Reaction with hydrogen peroxide gives an unusually stable hydroperoxide, Ph3COOH.

Acid-base properties
As a derivative of methanol, triphenylmethanol is expected to have a pKa in the range of 16-19. Typical of alcohols, resonance offers no stabilization of the conjugate base due to being bonded to a saturated carbon atom. Stabilization of the anion by solvation forces is largely ineffective due to the steric influence of the three phenyl groups.

The basicity of triphenylmethanol is enhanced due to the formation of a resonance-stabilized carbocation upon breaking of the C–O bond. After protonation of the oxygen under strongly acidic conditions, triphenylmethanol loses water to form the triphenylmethyl ("trityl") cation:
Ph3COH + H+ → Ph3C+ + H2O  
The trityl cation is one of the easiest carbocations to isolate, although it quickly reacts with water.

Synthesis
The preparation of triphenylmethanol from methyl benzoate or benzophenone and phenylmagnesium bromide is a common laboratory experiment for illustrating the Grignard reaction. An alternative starting material is diethyl carbonate.

Applications
Although not of major industrial importance, triphenylmethanol is a useful reagent in the research laboratory.  Substituted derivatives of triphenylmethanol are intermediates in the production of the commercially useful triarylmethane dyes.

References

Tertiary alcohols
Phenyl compounds
Substances discovered in the 19th century
Herman Lukoff. Herman Lukoff (May 2, 1923 – September 24, 1979) was a computer pioneer and fellow of the IEEE.

Formative years
Lukoff was born in Philadelphia, Pennsylvania to Aaron and Anna (Slemovitz) Lukoff. He graduated from the Moore School of Electrical Engineering at the University of Pennsylvania in 1943. While at the Moore School, he helped to develop the ENIAC and EDVAC computers. 

Lukoff subsequently followed ENIAC co-inventors J. Presper Eckert and John W. Mauchly to their newly formed Electronic Control Company, which became Eckert-Mauchly Computer Corporation, and then became part of Remington Rand in 1950 and Sperry Corporation in 1955. He also assisted Eckert and Mauchly with the development of the UNIVAC computer and was chief engineer of the UNIVAC LARC from 1955 to 1961. He stayed with the company until his death.

Death and interment
Lukoff died of leukemia on September 24, 1979, at Bryn Mawr Hospital in Bryn Mawr, Pennsylvania. At the time of his death, he lived in Fort Washington. Interred at Shalom Memorial Park in Huntingdon Valley, Pennsylvania, he was survived by his wife, Shirley Rosner Lukoff; his three sons, Arthur, Barry, and Andrew; and his daughter, Carol.

Publications
Lukoff's memoir, From Dits to Bits, details his experiences as a first-hand observer of the birth of the computer industry.

References

Further reading
 https://archives.upenn.edu/collections/finding-aid/upt50l694 
 http://doi.ieeecomputersociety.org/10.1109/MAHC.1980.10030
 http://www.smartcomputing.com/editorial/dictionary/detail.asp?guid=&searchtype=1&DicID=17591&RefType=Encyclopedia

People in information technology
Scientists from Philadelphia
1923 births
1979 deaths
University of Pennsylvania School of Engineering and Applied Science alumni
American computer scientists
Deaths from cancer in Pennsylvania
Strain hardening exponent. The strain hardening exponent (also called the strain hardening index), usually denoted , is a measured parameter that quantifies the ability of a material to become stronger due to strain hardening. Strain hardening (work hardening) is the process by which a material's load-bearing capacity increases during plastic (permanent) strain, or deformation. This characteristic is what sets ductile materials apart from brittle materials. The uniaxial tension test is the primary experimental method used to directly measure a material's stress–strain behavior, providing valuable insights into its strain-hardening behavior.  

The strain hardening exponent is sometimes regarded as a constant and occurs in forging and forming calculations as well as the formula known as Hollomon's equation (after John Herbert Hollomon Jr.) who originally posited it as: 

where  represents the applied true stress on the material,  is the true strain, and  is the strength coefficient.

The value of the strain hardening exponent lies between 0 and 1, with a value of 0 implying a perfectly plastic solid and a value of 1 representing a perfectly elastic solid. Most metals have an -value between 0.10 and 0.50. In one study, strain hardening exponent values extracted from tensile data from 58 steel pipes from natural gas pipelines were found to range from 0.08 to 0.25, with the lower end of the range dominated by high-strength low alloy steels and the upper end of the range mostly normalized steels.

Tabulation

References

External links
 More complete picture about the strain hardening exponent in the stress–strain curve on www.key-to-steel.com

Mechanical engineering
Solid mechanics
Code morphing. Code morphing is an approach used in obfuscating software to protect software applications from reverse engineering, analysis, modifications, and cracking. This technology protects intermediate level code such as compiled from Java and .NET languages (Oxygene, C#, Visual Basic, etc.) rather than binary object code. Code morphing breaks up the protected code into several processor commands or small command snippets and replaces them by others, while maintaining the same end result. Thus the protector obfuscates the code at the intermediate level.

Code morphing is a multilevel technology containing hundreds of unique code transformation patterns. In addition this technology transforms some intermediate layer commands into virtual machine commands (like p-code). Code morphing does not protect against runtime tracing, which can reveal the execution logic of any protected code.

Unlike other code protectors, there is no concept of code decryption with this method.  Protected code blocks are always in the executable state, and they are executed (interpreted) as transformed code. The original intermediate code is absent to a certain degree, but deobfuscation can still give a clear view of the original code flow.

Code morphing is also used to refer to the just-in-time compilation technology used in Transmeta processors such as the Crusoe and Efficeon to implement the x86 instruction set architecture.

Code morphing is often used in obfuscating the copy protection or other checks that a program makes to determine whether it is a valid, authentic installation, or an unauthorized copy, in order to make the removal of the copy-protection code more difficult than would otherwise be the case.

See also
 Intermediate language

References 

Software obfuscation
Source code
Warez
K virtual machine. The K virtual machine (KVM) is a virtual machine developed by Sun Microsystems (now owned by Oracle Corporation), derived from the Java virtual machine (JVM) specification. The KVM was written from scratch in the programming language C. It is designed for small devices with 128K to 256K of available computer memory, and minimizes memory use. It supports a subset of the features of the higher end JVM. For example, a KVM may not support floating-point arithmetic and object finalization. The Connected Limited Device Configuration (CLDC) specifies use of the KVM. The 'K' in KVM stands for kilobyte, signifying that the KVM runs in kilobytes of memory in contrast to megabytes.

See also 

Java virtual machine

References

Sun Microsystems
Oracle Corporation
Discontinued Java virtual machines
Benzanthrone. Benzanthrone (BZA) is a polycyclic aromatic hydrocarbon.  It is a yellow solid. Its derivatives are used as a dyestuff intermediate for anthraquinone-based dyes. Dehydrogenative coupling gives violanthrone.  It is prepared by reduction of anthroquinone to anthrone followed by alkylation with a mixture of glycerol and sulfuric acid.

It is a basic substance with fluorescent and luminescent properties. It can be used for photosensitization, and as a charge transport material. It is also used in pyrotechnics industry, mainly as a component of some older formulations of green and yellow colored smokes, often together with Vat Yellow 4; its US military specification is MIL-D-50074D.

Safety 
Benzanthrone causes itching and burning sensations on exposed skin, together with erythema, dermatitis, and skin pigmentation.

See also
 3-Nitrobenzanthrone

References

External links
 National Pollutant Inventory - Polycyclic Aromatic Hydrocarbon Fact Sheet

Fluorescent dyes
Ketones
Polycyclic aromatic compounds
SETI@home beta. SETI@home beta, is a hibernating volunteer computing project using the Berkeley Open Infrastructure for Network Computing (BOINC) platform, as a test environment for future SETI@home projects:

 AstroPulse is a volunteer computing project searching for primordial black holes, pulsars, and ETI. AstroPulse clients have been tested by this project for nearly 6 years. It is already running on SETI@home, testing new GPU/CPU optimized apps and performing other tasks.
 SETI Southern Hemisphere Search, which is another SETI@home project that was due to join BOINC. It was expected that this project would use a slightly modified version of the SETI enhanced client, as the Parkes Observatory has a feedhorn with more beams than the Arecibo Observatory.

Applications Testing
11 Dec 2008, CUDA applications test
3 Jun 2013, SETI@home v7 test
01 Dec 2015 SETI@home v8 test

External links

References

Science in society
Free science software
Volunteer computing projects
Science software for macOS
Science software for Linux
Science software for Windows
Software that uses wxWidgets
Attribute domain. In computing, the attribute domain is the set of values allowed in an attribute.

For example: 
 Rooms in hotel (1–300)
 Age (1–99)
 Married (yes or no)
 Nationality (Nepalese, Indian, American, or British)
 Colors (Red, Yellow, Green)

For the relational model it is a requirement that each part of a tuple be atomic. The consequence is that each value in the tuple must be of some basic type, like a string or an integer. For the elementary type to be atomic it cannot be broken into more pieces. Alas, the domain is an elementary type, and attribute domain the domain a given attribute belongs to an abstraction belonging to or characteristic of an entity.

For example, in SQL, one can create their own domain for an attribute with the command

CREATE DOMAIN SSN_TYPE AS CHAR(9);

The above command says: "Create a datatype SSN_TYPE that is of character type with size 9".

References

Type theory
Database theory
W1. W1 could refer to:

 W1, a postcode district in the W postcode area of London
 British NVC community W1 (Salix cinerea - Galium palustre woodland), one of the woodland communities of the British National Vegetation Classification
 W-1 tool steel, a water-hardening steel
 one of four manuscripts containing the Magnus Liber, or Magnus liber organi, a compilation of medieval music. The term is derived from the Wolfenbüttel library which holds the manuscript (Herzog August Bibliothek).
 GN W-1, an electric locomotive built for the Great Northern Railway
 LNER Class W1, an experimental locomotive designed by Sir Nigel Gresley for the London and North Eastern Railway
 second step of the W0-W6 scale for the classification of meteorites by weathering
 Wrestle-1, a Japanese professional wrestling promotion
 The computational complexity class W[1] in parameterized complexity
 The Apple W1 wireless pairing chip primarily used in AirPods
 W1 tram, a class of electric trams built by the Melbourne & Metropolitan Tramways Board.
 McLaren W1, a sports car succeeding the F1 and P1
 W-1, an experimental aircraft later known as the ERCO Ercoupe

W-1 could refer to:
 U.S. uniformed services pay grades#Warrant Officer pay grades

See also
WI (disambiguation)
1W (disambiguation)
Bristol Siddeley BS.100. The  Bristol Siddeley BS.100 is a British twin-spool, vectored thrust, turbofan aero engine that first ran in 1960. The engine was designed and built in limited numbers by Bristol Siddeley Engines Limited. The project was cancelled in early 1965.

Design and development
Based on the 300-series Olympus, the BS.100 was similar in general arrangement to that of the company's Pegasus design, but with the addition of plenum chamber burning (PCB), to enable the projected Hawker Siddeley P.1154 VSTOL fighter design to accelerate to supersonic speed  and to allow the aircraft to hover. 

PCB is similar to reheat, but combustion is only applied to the bypass air (i.e. the front nozzles). PCB was quite difficult to develop since combustion had to occur on the bends between fan exit and entry to the two vectoring front nozzles and at much lower inlet pressure and temperature than a conventional afterburner. The PCB flame-holders were highly complex sheet metal fabrications which were difficult to envisage on a 2D engineering drawing. Consequently 3D models in wood had to be produced to aid development of the system. 

Variable area front nozzles were required. This was to be achieved by movable ramps mounted horizontally on the fuselage between the front and rear nozzles. For vertical flight and subsonic cruise, the nozzle area would be large, whereas with the PCB lit during acceleration to supersonic speed the ramps would be expanded, reducing flow to the front nozzles and diverting more flow into the core.
 
Although PCB ran on a Pegasus 2 development engine, it was never fitted to any of the BS.100-8 engines that were built and never flew.

The BS.100 was also intended for the Fokker Republic D-24.

Variants
A range of BS.100 engines were studied in the early 1960s, but it was the BS.100-8 that was finally selected for development manufacture and was actually built.

Engines on display
A preserved Bristol Siddeley BS.100 is on public display at the Fleet Air Arm Museum, RNAS Yeovilton.

Specifications (BS.100-8)

See also

References

Notes

Bibliography

 Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. 
 Dow, Andrew. Pegasus - The heart of the Harrier. Barnsley, South Yorkshire. Pen and Sword, 2009.

External links

P.1154 history at harrier.org 

Low-bypass turbofan engines
BS100
1960s turbofan engines