omniomni/omni-engineering huggingface dataset:
Signaling System No. 5. The Signaling System No. 5 (SS5) is a multi-frequency (MF) telephone signaling system that was in use from the 1970s for International Direct Distance Dialing (IDDD). Internationally it became known as CCITT5 or CC5.  It was also nicknamed Atlantic Code because it was used for the first IDDD connections between Europe and North America.

Signaling systems in use at the time were designed for in-band signaling, meaning they used the same channel as the media that they controlled. SS5 was designed for inter-continental traffic for which many transmission paths were long terrestrial, often submarine cable, and geostationary satellite links.  Trunks using satellite links also had echo suppressors connected at their end points.  SS5 was specifically designed to work within those links.

Based on the Bell System multi-frequency (MF) signaling system known by CCITT as Regional System R1, it used six signaling frequencies: 700 Hz (A), 900 Hz (B), 1100 Hz (C), 1300 Hz (D), 1500 Hz (E) and 1700 Hz (F).  The first five frequencies were used in a two-out-of-five code to represent decimal numbers (telephone numbers), and the last frequency in combination with one of the others represented the beginning or end of a sequence of digits. These frequencies were combined to encode the following signals:

The 2 out of 6 frequency code was used to pass digits forward between Registers in traditional International Switching Centres.  Each digit took 55 ms with a 55 ms Inter-digital pause (IDP) and the sequence was sent 'en-bloc' to ensure that Echo Suppressors would not switch out the forward path as the links tended often to be satellite channels.  The first digit was a keying Prefix (a KP) to indicate Terminal or Transit working and the last digit was the digit 15 or Keying Finish (KF).

In addition, for line signaling a 2 frequency (2VF) code using compelled sequences of 2400 Hz and 2600 Hz rather than continuous SF tone was used to seize the line at the beginning of a call over that trunk and clear it at the end of the call - long after the valuable register had sent 15 or KF and dissociated from the call. This Line signalling element was 2VF to introduce the possibility of more meanings and tone-off idle in order that hundreds of channels in transmission media would not be transmitting standing tones simultaneously.

Abuse and fraud
The deficiencies of SS5 are widely known as the root cause for "Blue box fraud" that enabled phone phreaks, such as Captain Crunch (John Draper), to abuse the telephone system and place telephone calls for free, among exploiting other capabilities. SS5 was abused by sending a "seize" signal to simulate and pose as a telephone switching system from a subscriber telephone line. This enabled the perpetrator to control the remote switch that had no means for distinguishing the signaling from that of another legitimate switch.

This fraud was a factor in the widespread adoption of  Signalling System No. 7 (SS7) in replacement of SS5.

See also

Signaling System No. 6

References

Telephony signals
Centro de Investigación de Métodos Computacionales. Centro de Investigación de Métodos Computacionales (CIMEC, Research Center for Computational Methods) is a research institute located at Predio CONICET Santa Fe Santa Fe, Argentina.

It depends on the Universidad Nacional del Litoral, and on the National Scientific and Technical Research Council (CONICET). The main area of research is Computational mechanics, i.e. the application of numerical methods to various areas of engineering.

The center was formerly known as Centro Internacional de Métodos Computacionales en Ingeniería.

Additional information in the official site below.

External links
Official site 

Research institutes in Argentina
Engineering research institutes
Santa Fe Province
Parque Tecnológico del Litoral Centro. Parque Tecnologico del Litoral Centro SAPEM (PTLC Technological Park of the Litoral Centro), is both an institution and a complex of buildings located near Santa Fe, Argentina, created by the National Scientific and Technical Research Council (CONICET) for the geographical concentration of scientific research and development projects of the area.

The institution promotes the realization of scientific projects through financial support and providing areas to conduct these projects, as well as facilitating the integration of technology transfer to production companies.

There is also an "Enterprise Incubator" where new firms can develop their business basis to prepare until they can function properly.

External links
  

Scientific organisations based in Argentina
Buildings and structures in Santa Fe Province
Over-the-horizon Airborne Sensor Information System. The Over-the-horizon Airborne Sensor Information System (OASIS) is an organic over the horizon sensor targeting and surveillance system originally produced by Texas Instruments and now by Raytheon.

It is coupled with link 16, electro-optics/infrared, radar, GPS, Tactical Data Information Exchange System TADIX-B and Officer in Tactical Command Information Exchange System (OTCIXS) information to provide a coherent tactical picture for the user.  OASIS III is a hybrid of OASIS and processes and correlates all data provided via Multi-Mission Advanced Tactical Terminal (MATT) and Mini-Demand Assigned Multiple Access (DAMA). The OASIS III tactical data processor provides an (OTCIXS) message link, coupled with GPS-aided targeting using the AN/APS-137B(V)5 Radar.

External links 
 Tactical Data Information Exchange Subsystem
 Raytheon
 South Asia Analysis Group

Military aviation
VL Humu. The VL Humu (Whirlwind) is a Finnish fighter aircraft, designed by Valtion lentokonetehdas in 1944, and based on the American Brewster F2A Buffalo.

Design and development
The Finnish Air Force had acquired 40+ surplus B-239 naval variants of the Brewster Buffalo and put them to good use during the Winter War, so it was decided in 1942 to produce a copy due to aircraft shortages. Chief designer Martti Vainio, along with designers Torsti Verkkola, Arvo Ylinen at Valtion Lentokonetehdas were tasked with designing the new aircraft as well as a replacement wing made of wood instead of metal.

The Humu was largely constructed out of wood due to scarcity of metals, but the frame was made from steel and its design followed closely that of the Brewster. It was planned that captured Soviet engines and instrument panels would be used. It was powered by a 930hp Shvetsov M-63 engine, previously tested on a Brewster. The wooden wing added 250 kg of extra weight and moving the fuels tanks from the wing to the aft fuselage adversely affected maneuverability due to the center of gravity being shifted.

The first flight took place on 8 August 1944. Later flight testing gave a total flight time of 19 hours and 50 minutes. The aircraft was  heavier than calculated, its engine was underpowered, and it was felt that the fighter would not be able to compete against enemy aircraft. The end of the Continuation War in September 1944, combined with the aircraft's poor performance, however, put the end to the project.

Operators

 Finnish Air Force

Aircraft on display
The sole Humu, HM-671, was placed in storage in 1945. It was restored between 1972 and 1974 and is displayed at the Central Finland Aviation museum.

Specifications (VL Humu)

See also

References

Further reading

External links

The VL Humu at Central Finland Aviation museum

Humu
1940s Finnish fighter aircraft
Single-engined tractor aircraft
Mid-wing aircraft
Aircraft first flown in 1944
Aircraft with retractable conventional landing gear
Single-engined piston aircraft
Intracom Holdings. Intracom Holdings is the main shareholder of a group of multinational companies specialized in IT services, construction projects and defense electronics systems.

Overview 
The core companies of the Intracom Holdings Group are:

 Intrakat, one of the top five construction companies in Greece with 2457 employees.
 IDE (Intracom Defense Electronics), a supplier of defense electronics, advanced communication systems and defense applications software, currently expanding into the design and manufacturing of hybrid energy systems.

Listed on the Athens Stock Exchange since 1990, Intracom maintained a strong presence in the Greek and international markets, with 16 subsidiaries abroad while its international activity extends to 70 countries.

References

External links 
L.S. Skartsis, "Greek Vehicle & Machine Manufacturers 1800 to present: A Pictorial History", Marathon (2012)  (eBook)

Software companies of Greece
Telecommunications equipment vendors
Electronics companies of Greece
Defence companies of Greece
Manufacturing companies based in Athens
Companies listed on the Athens Exchange
Software companies established in 1977
Intracom Group
Greek brands
Multinational companies headquartered in Greece
Electronics companies established in 1977
Greek companies established in 1977
Parser Grammar Engine. The Parser Grammar Engine (PGE, originally the Parrot Grammar Engine) is a compiler and runtime system for Raku rules for the Parrot virtual machine. PGE uses these rules to convert a parsing expression grammar into Parrot bytecode. It is therefore compiling rules into a program, unlike most virtual machines and runtimes, which store regular expressions in a secondary internal format that is then interpreted at runtime by a regular expression engine. The rules format used by PGE can express any regular expression and most formal grammars, and as such it forms the first link in the compiler chain for all of Parrot's front-end languages.

When executed, the bytecode generated by PGE will parse text as described in the input rules, generating a parse tree. The parse tree can be manipulated directly, or fed into the next stage of the Parrot compiler toolchain to generate an abstract syntax tree (AST) from which code can be  generated; if the grammar describes a programming language.

History
Originally named P6GE and written in C, PGE was translated to native Parrot and renamed not long after its initial release in November 2004. Its author is Patrick R. Michaud. PGE was written to reduce the amount of work needed to implement a compiler on Parrot. It was also written to allow Perl 6 to easily self-host, though current Pugs development no longer uses PGE as its main rules back-end in favor of a native engine named PCR.

Internals
PGE combines three styles of parsing:
 Raku rules
 an operator-precedence parser
 custom parse subroutines
The primary form is Raku rules, so a PGE rule might look like this for an addition-only grammar:
 rule term   { <number> | \( <expr> \) }
 rule number { \d+ }
 rule expr   { <term> ( '+' <term> )* }
The operator precedence parser allows an operator table to be built and used directly in a Perl 6 rule style parser like so:
 rule expr is optable { ... }
 rule term   { <number> | \( <expr> \) }
 rule number { \d+ }
 proto term: is precedence('=')
             is parsed(&term) {...}
 proto infix:+ is looser('term:') {...}
This accomplishes the same goal of defining a simple, addition-only grammar, but does so using a combination of a Raku style regex/rules for term and number and a shift-reduce optable for everything else.

Code generation 
Though PGE outputs code which will parse the grammar described by a rule, and can be used at runtime to handle simple grammars and regular expressions found in code, its main purpose is to parse high-level programming languages.

The Parrot compiler toolchain is broken into several parts, of which PGE is the first. PGE converts source code to parse trees. The tree grammar engine (TGE) then converts these into a Parrot abstract syntax trees (PAST). A second TGE pass then converts a PAST into Parrot opcode syntax trees (POST) which can be directly transformed into executable bytecode.

References

External links

Perl
Formal languages
Pattern matching
Beta software
Compilers
Interpreters (computing)
Transarc. Transarc Corporation was a private Pittsburgh-based software company founded in 1989 by Jeffrey Eppinger, Michael L. Kazar,  Alfred Spector, and Dean Thompson of Carnegie Mellon University.

Transarc commercialized the Andrew File System (AFS), now OpenAFS, which was originally developed at Carnegie Mellon.  As a member of the Open Software Foundation (later The Open Group), Transarc developed the DFS distributed filesystem component of the Distributed Computing Environment (DCE) that was sold by Open Group members.  Other products included the distributed transaction processing system Encina (a basis for IBM's UNIX-based CICS products; included in IBM's TXSeries and later WebSphere), and the Solaris binary distribution of the DCE.

Transarc was purchased by IBM in 1994
and became the IBM Transarc Lab in 1999 and then the IBM Pittsburgh Lab in 2001. The lab was closed in 2002.

References

External links
Transarc Corporate Overview from 1999

Defunct software companies of the United States
Defunct companies based in Pennsylvania
Companies established in 1989
IBM acquisitions
High Order Language Working Group. The High Order Language Working Group (HOLWG) was a working group instrumental in developing the Ada computer programming language. The group was established in 1975 with the goal of establishing a single high-level programming language appropriate for United States Department of Defense (DoD) real-time embedded computer systems. Colonel William A. Whitaker chaired the group.

The group was centered in the US, but input was solicited from international experts. European experts responded well, which was valuable since language research there, during the prior decade, was more active than in the US. Some highly accomplished academics were paid including Edsger W. Dijkstra, Charles Antony Richard Hoare, and Niklaus Wirth.

HOLWG had three objectives:

 formulate the requirements for common DoD high order languages;
 compare those requirements with existing languages; and
 recommend adoption or implementation of the necessary common languages.

References 
 Ada - The Project The DoD High Order Language Working Group, William A. Whitaker, Colonel USAF, Retired

Working groups
Ada (programming language)
Platte Bridge Railroad Tragedy. The Platte Bridge Railroad Tragedy was a bushwhacker attack on the Hannibal and St. Joseph Railroad during the American Civil War on September 3, 1861, in which the train derailed on a bridge over the Platte River east of St. Joseph, Missouri, killing between 17 and 20 and injuring 100. The bridge crosses the river in Buchanan County, between Marion Township on the east, and Washington Township on the west.

Confederate partisans planned to burn the lower timbers of the  bridge across the river, leaving the top looking intact. At 11:15 p.m. on a moonless night, the westbound passenger train from Hannibal, Missouri, to St. Joseph started to cross the bridge. The supports cracked and gave way. The locomotive flipped, falling  into the shallow river and bringing with it the freight cars, baggage car, mail car and two passenger cars with 100 men, women and children. Bodies and the injured were taken to the Patee House near the St. Joseph depot. Union soldiers were ordered to track down and execute bushwhackers for their part in the incident.  

Confederate Major General Sterling Price, who had been invading northern Missouri at the time, wrote Union commanding general Henry Wager Halleck to protest, stating the sabotage was "lawful and proper" according to the rules of warfare and that the captured men should be treated as prisoners of war. Halleck replied that the bushwhackers were "spies, marauders, robbers, incendiaries, guerrilla bands...in the garb of peaceful citizens". The bushwhackers were also to say that the train was a military target because there were soldiers on it bound for Fort Leavenworth, Kansas. One of the soldiers killed was Barclay Coppock, a member of John Brown's raid on Harper's Ferry. The bushwackers were also to claim that it was an attempt to assassinate former Missouri Governor Robert Marcellus Stewart.

The most prominent of the bushwhackers sought by the Federal troops was Silas M. Gordon. Union troops were to burn Platte City, Missouri twice (in December 1861 and July 1864) in unsuccessful attempts to force the townspeople to surrender him (see the Burning of Platte City).

The railroad at the time was the first to cross the state of Missouri and it was used to deliver mail to and from the Pony Express terminus in St. Joseph, Missouri. Col. Ulysses S. Grant's first commission in the Civil War had been guarding the trains. In August he was promoted to brigadier general on a new assignment.

References
 

Missouri in the American Civil War
Buchanan County, Missouri
Rail sabotage in the United States
Transportation disasters in Missouri
Railway accidents in 1861
Bridge disasters in the United States
Bridge disasters caused by warfare
Passenger rail transportation in Missouri
1861 in Missouri
Accidents and incidents involving Hannibal and St. Joseph Railroad
September 1861
Advanced Enclosed Mast/Sensor. The US Navy's Advanced Enclosed Mast/Sensor (AEM/S) system fully integrates advanced materials, structures, and manufacturing technologies with sensor technology, electromagnetics, and signature reduction.

Ship masts, with the complex antenna geometries mounted on them, as well as the latticework of the mast structure, contribute significantly to a ship's radar cross section. The AEM/S consists of a faceted radome that provides a cleaner exterior profile, with internal platforms on which antennas and sensors are mounted. The radome material is designed so that the antennas can transmit and receive through the material. The base of the mast is constructed from fiber reinforced composite skins encasing end-grain balsa core. The upper (radome) section consists of structural foam and fiberglass.

In May 1997, USS Arthur W. Radford received the first-ever shipboard installation of the AEM/S System, to serve as a proof-of-concept or advanced technology demonstrator. Sailors reported an unanticipated benefit of being able to work aloft in bad weather, increasing the efficiency of scheduled shipboard maintenance.

Using lessons learned from the Radford, the Navy designed the AEM/S into a new class of ships, the first being the USS San Antonio (LPD-17) amphibious transport dock.

References

External links
Federation of American Scientists information page on the Advanced Enclosed Mast/Sensor

Equipment of the United States Navy
Hydrologic Evaluation of Landfill Performance. The Hydrologic Evaluation of Landfill Performance (HELP) model is a quasi-two-dimensional hydrologic numerical model for conducting water balance analysis of landfills, cover systems, and other solid waste containment facilities; it was developed for the United States Environmental Protection Agency.

Versions
Public domain (free) version:
HELP v4.0 – Microsoft Excel-based version developed by EPA ORD's Center for Environmental Solutions and Emergency Management, HELP 4 user manual and further documentation for HELP v3.0
Commercial versions:
Visual HELP – based on the HELP version 3.07, offers a Microsoft Windows GUI to view and edit soil profiles and to generate weather data.
HELP 3.95 D – by Dr. Klaus Berger at the University of Hamburg; offers a Microsoft Windows UI and includes the model HELP 3.07 and the enhanced model HELP 3.95 D.

References

Landfill
Hydrology models
Robert Weitbrecht. Robert Haig Weitbrecht (1920-1983) was an engineer at SRI International and later the spin-off company Weitbrecht Communications who invented a type of a modem (a form of acoustic coupler).

Early life and education
Weitbrecht was born in Orange, California in 1920. He was born Deaf and his education was mainstream for the most part with the exception of acquiring some signing and lip-reading skills from a Deaf school early on. He went on to earn a B.S. in Astronomy from the University of California, Berkeley in 1942 and finished his formal education with a M.S. in Astronomy from the University of Chicago in 1957.

Career
Weitbrecht was initially a physicist at the Radiation Laboratory at the University of California (now Lawrence Livermore National Laboratory), then an electronics scientist at the U.S. Naval Air Missile Test Center. For his efforts, he earned the United States Navy's Superior Accomplishment Award.

Even in his high school days, Weitbrecht was interested in amateur radio and used radiotelegraph to communicate with fellow radio operators around the country. In 1964, this love for communication came together with the need to interact with a colleague who could not operate an amateur radio. To solve this problem, Weitbrecht created a device that used the public telephone system to achieve communication: the teletypewriter (TTY).

After being approached by James C. Marsters, Weitbrecht came up with a revised design for the acoustic coupler (a type of modem), which used echo suppression. In 1964, Marsters and Weitbrecht adapted used teletypewriter equipment, and Weitbrecht made the first successful teletypewriter phone call from one deaf person to another. It took several tries, until Weitbrecht's words appeared clearly: "Are you printing now? Let's quit for now and gloat over the success." Today, this type of device is known as a telecommunications device for the deaf.

Personal life
Weitbrecht earned a pilot's license in 1967. Weitbrecht died after being involved in an automobile accident in 1983.

References

External links
Finding Aid to the Robert Weitbrecht papers, 1931-1982, The Bancroft Library

1920 births
1983 deaths
People from Orange, California
SRI International people
Manhattan Project people
Scientists from the San Francisco Bay Area
UC Berkeley College of Letters and Science alumni
American deaf people
20th-century American inventors