omniomni/omni-engineering huggingface dataset:
SP-1 switch. SP-1 (Stored Program 1) was the name of a computerized telephone exchange (a so-called switching office) manufactured by Northern Electric (later Northern Telecom and now Nortel Networks beginning in 1972) in Canada. It was introduced in 1971 (as stated in a Northern Telecom print ad that is included (page 55) in a history of Nortel, written by Peter C. Newman who was commissioned by Nortel to write it. Copyright is 1995. No ISBN.)

As indicated by the name "Stored Program", the SP-1 introduced computer control to the telephone switching market. (AT&T's #1ESS preceded the SP-1 by several years.)

A central computer controlled the operation of the switch. Switch behavior was determined by the operation of a computer program. 

With its use of computer hardware and software control, the SP-1 marked an evolutionary step in telephony design. It was an intermediate form between the previous generation of electromechanical systems and the next generation of fully digital systems. Like the previous generation of systems, the SP-1 was an analog switch that used a special form of mechanical relay (Minibar crossbar switch) to provide the voice connections. The voice signal remained in the analog domain throughout the exchange, with the crossbar switches providing a metallic path to connect the end points of a call together. However the SP1 replaced the previous generation's complex relay-based controllers (markers) with a modern Harvard architecture electronic computer, with separate data and program memories. SSI DTL logic was used throughout.  Two types of memory was used - ferrite sheet memory for the CPU  and Piggyback Twistor memory for the storage of program and routing information.  A number of variations on the base switch were available.  A "two wire" version for local service, a four wire version for toll service. Two/four wire versions were also available as was a TOPS variant that was used to provide Operator services. The first four wire switch  (four wire-tops, i.e., it provided toll switching and operator services) was placed in service in Thunder Bay circa 1972.  The operator service consoles (CRTs) used an Intel 4004 processor.

The next generation of systems evolved from the SP1 design to replace the analog switch with a digital technology.  
SP-1 proved the feasibility of software-controlled systems for telephony.  It set the stage for the introduction of fully digital systems with the development of the DMS (Digital Multiplex Systems) by Nortel in the 1970s. (Nortel's SL-1 (PBX) was Nortel's first fully digital switching system, and it was introduced in service in 1975.)

See also
DMS-100
Electronic Switching System
1ESS switch
TXE
Stored Program Control exchange
SP-1 Technical Bulletin

Telephone exchange equipment
Nortel products
Quikkit Glass Goose. The Quikkit Glass Goose is an American two-seat biplane amphibious aircraft, designed by Tom Scott and marketed for homebuilding by Quikkit of Dallas, Texas.

The Glass Goose is based on the earlier Sea Hawker, which was designed by Garry LeGare in 1982 and sold through his firm Aero Gare as the Sea Hawk and, later, Sea Hawker. LeGare sold the rights to the aircraft to Aero Composites in 1986, which sold them again two years later to (unrelated) Aero Composite Technologies.

Design and development
Tom Scott purchased a Sea Hawker kit in October 1984 and completed the aircraft in March 1986, constructing the aircraft according to the plans. He was not happy with the resulting aircraft and over five years incorporated improvements to address performance and stability shortcomings. The final design has more wing area, a larger hull surface and improved pylon aerodynamics, plus many other improvements. This redesign became the Glass Goose kit.

The Glass Goose features a cantilever biplane layout, without interplane struts, a two-seats-in-side-by-side configuration enclosed cockpit under a bubble canopy, retractable tricycle landing gear and a single engine in pusher configuration.

The aircraft is made from composites. Its  span wing has an area of . Standard engines used are  Lycomings, although the eight-cylinder  Jabiru 5100 and Mazda Wankel engines have also been employed.

In 2013, Kitplanes Magazine reported that they could not reach the Quikkit Division of Rainbow Flyers, Inc., the Glass Goose kit manufacturer, so they considered the design unavailable.

Specifications (Glass Goose)

References

External links

Official website archives on Archive.org
"Glass Goose", Buyer's Guide, in Kitplanes Magazine
"Sea Hawk / Sea Hawker / Glass Goose," EAA (summary data and index of related articles in EAA publications).
 "Builder: Wayne Peach; Aircraft: Sea Hawker / Glass Goose", in "Projects", in "Builder's Projects", EAA Chapter 838.

Single-engined pusher aircraft
1980s United States civil utility aircraft
Flying boats
Amphibious aircraft
Homebuilt aircraft
Glass Goose
Biplanes
Composability. Composability is a system design principle that deals with the inter-relationships of components. A highly composable system provides components that can be selected and assembled in various combinations to satisfy specific user requirements. In information systems, the essential features  that make a component composable are that it be:
 self-contained (modular): it can be deployed independently – note that it may cooperate with other components, but dependent components are replaceable
stateless: it treats each request as an independent transaction, unrelated to any previous request. Stateless is just one technique; managed state and transactional systems can also be composable, but with greater difficulty.

It is widely believed that composable systems are more trustworthy than non-composable systems because it is easier to evaluate their individual parts.

Simulation theory 

In simulation theory, current literature distinguishes between Composability of Models and Interoperability of Simulation. Modeling is understood as the purposeful abstraction of reality, resulting in the formal specification of a conceptualization and underlying assumptions and constraints. Modeling and simulation (M&S) is, in particular, interested in models that are used to support the implementation of an executable version on a computer. The execution of a model over time is understood as the simulation. While modeling targets the conceptualization, simulation challenges mainly focus on implementation, in other words, modeling resides on the abstraction level, whereas simulation resides on the implementation level. Following the ideas derived from the Levels of Conceptual Interoperability model (LCIM), Composability addresses the model challenges on higher levels, interoperability deals with simulation implementation issues, and integratability with network questions. Tolk  proposes the following definitions: Interoperability allows exchanging information between the systems and using the information in the receiving system. Composability ensures the consistent representation of truth in all participating simulation systems of the federation.

See also 
 Minimal structured control flow
 Function composition
 Object composition
 Principle of compositionality
 Composable operations
 Universal composability

References 

Software engineering terminology
Smart cow problem. The smart cow problem is the idea that a technically difficult task may only need to be solved once, by one person, for less technically proficient group members to accomplish the task using an easily repeatable method. The term is derived from the expression: "It only takes one smart cow to open the latch of the gate, and then all the other cows follow."

This concept has been applied to digital rights management (DRM), where, due to the rapid spread of information on the Internet, it only takes one individual's defeat of a DRM scheme to render the method obsolete.

See also 
 Jon Lech Johansen aka "DVD Jon", among the first hackers to crack DVD encryption
 Script kiddie, an unskilled hacker who relies on tools created by others

References 

Digital rights management
Hacker culture
Metaphors referring to cattle
Technology neologisms
Lake Hodges Bridge. The Lake Hodges Bridge is a component of Interstate 15 that spans Lake Hodges in San Diego, California, just south of the city limits of Escondido. It is an important part of San Diego's north–south transportation axis. Depending on the amount of rainfall in San Diego County, Lake Hodges's water level fluctuates significantly. As such, the bridge may cross over water or a dry lake bed. Due to the vast amount of vegetation that springs up when water levels are low, the area below the bridge has been jokingly referred to as "Hodges National Forest".

The original bridge was constructed in 1919. The bridge later became integrated into the newly constructed U.S. Route 395. As part of a roadway realignment and improvement project, the original structure was demolished in 1968, and replaced with a new structure in 1969. That bridge was subsequently replaced in 1981, when I-15 was built to supersede US 395. The current bridge is a concrete viaduct. It was widened and replaced in 2006-2009 as part of a project to add managed lanes in the I-15 corridor.

As a traffic bottleneck, the bridge is vulnerable to traffic jams in North San Diego County. The nature of the lake and the surrounding land makes the bridge the singular access into the city of San Diego from inland North County. The only two major ways around the bridge are the Del Dios Highway, a two-lane winding road to Interstate 5 via Del Mar, and the  trip through Ramona into Escondido. Although paved access roads through the San Pasqual Valley to the east of Lake Hodges do exist, they are lightly traveled and are not designed to handle heavy traffic. The bridge is thus effectively the only crossing point for drivers on the route.

Lake Hodges Pedestrian Bridge 
The Lake Hodges Pedestrian Bridge, officially named the David Kreitzer Lake Hodges Bicycle Pedestrian Bridge after a retired planning commissioner, is a pedestrian bridge spanning Lake Hodges immediately south of the Interstate 15 span. The bridge was opened to the public on May 15, 2009.

The bridge is of a stress-ribbon design, the longest of its type in the world, and only the sixth to have been built in the US. From end to end the bridge measures . This design was chosen for having the least impact on environmentally sensitive habitats in the construction area.

See also 
 bicycle bridge

References

Bridges in San Diego
Bridges on the Interstate Highway System
Road bridges in California
Interstate 15
Bridges completed in 1919
Bridges completed in 1969
Bridges completed in 1981
Bridges completed in 2009
Buildings and structures demolished in 1968
Concrete bridges in California
Stressed ribbon bridges in the United States
1919 establishments in California
LWS-2. The LWS-2 was the Polish air ambulance aircraft prototype, designed in the late-1930s in the LWS factory (Lublin Aircraft Factory).

Design and development
The LWS-2 was designed as a light ambulance aircraft, for a requirement of the Polish Air Force and the Polish Red Cross (PCK), which was operating military ambulances. A preliminary design was made in 1936 by Zbysław Ciołkosz, the main designer of the LWS factory, follower by Jerzy Teisseyre's detailed design. It was influenced by RWD-9 and RWD-13 planes of the RWD team, especially their wing construction with rich wing mechanization, that gave it STOL capabilities. The prototype was built using PCK funds. Aircraft was registered SP-ATP and flown in autumn of 1937.

The Polish Red Cross ordered six aircraft, but the LWS factory was busy at that time with military production (RWD-14 Czapla and LWS-3 Mewa), and they were not built by the outbreak of World War II. LWS's next design, the LWS-3 Mewa close reconnaissance plane, utilized many features of the LWS-2, and was generally similar.

Description
Mixed construction (steel and wood) braced high-wing monoplane, conventional in layout. Fuselage of a steel frame, canvas covered (engine part with duralumin). Two-spar straight wings of wooden construction, with slats, flaps and flaperons, covered with canvas and plywood (in front), rectangular with rounded tips and narrowing near the fuselage. The wings were supported with V-struts and were folding rearwards. Cantilever empennage, covered with plywood (stabilizers) and canvas (rudder and elevators). Conventional fixed landing gear, with a rear skid. Capacity of four in a closed cockpit: a pilot in front, a doctor behind him, and two lying on stretchers at the back. It had a 9-cylinder air-cooled Avia-built Wright Whirlwind J-5 radial engine delivering 220 hp (164 kW) nominal power and 240 hp (179 kW) take-off power. Two-blade metal propeller Ratier, of variable pitch. A 130-liter fuel tank behind the engine. Cruise fuel consumption 48 L/h.

Operational history
On May 19, 1938 the prototype was given to the Air Force. Between July 1 and July 4, 1938, the LWS-2 prototype took part in an International Ambulance Aircraft Contest in Esch in Luxembourg, and won first place and a cup for the best accommodation in a cab for the injured.

The prototype was later used by the Polish Red Cross. Its fate during the World War II is not clear, as the damaged plane was captured by the Germans on airfield at Krosno.

Operators

Polish Red Cross operated one prototype, ordered 6 aircraft, none delivered.

Specifications (LWS-2)

See also

References

External links

Photos and drawings at Ugolok Neba

1930s Polish civil utility aircraft
1930s Polish military utility aircraft
Single-engined tractor aircraft
High-wing aircraft
Aircraft first flown in 1937
Aircraft with fixed conventional landing gear
William Pugh (computer scientist). William Worthington Pugh Jr. (born 1960) is an American computer scientist who invented the skip list and the Omega test for deciding Presburger arithmetic. He was the co-author of the static code analysis tool FindBugs, and was highly influential in the development of the current memory model of the Java language. Pugh received a Ph.D. in computer science, with a minor in acting, from Cornell University. His thesis advisor was Tim Teitelbaum.

In 2012 he became professor emeritus of the University of Maryland's department of computer science in College Park. He is on the technical advisory board for the static analysis company Fortify Software.

References

External links
 Website

American computer scientists
Living people
University of Maryland, College Park faculty
1960 births
USS Rancocas. USS Rancocas (LS-1) is the former name of an engineering development facility at the border between Moorestown Township and Mount Laurel Township, New Jersey. In May 2008, it was formally renamed the Vice Admiral James H. Doyle, Jr. Combat System Engineering Development Site (CSEDS).

It is located between Hartford Road and County Route 537 in Moorestown and resembles a warehouse with the superstructure of a planned, but never built naval strike cruiser sitting on the roof.  The design of the superstructure was later incorporated into the design of the .  The facility was initially constructed for the United States Air Force in 1958, to support AN/FPS-49 Ballistic Missile Early Warning System development.  It briefly operated as a sensor for the SPACETRACK program but was transferred to the U.S. Navy and refurbished in 1976 to support Aegis Combat System development.  It is still used by Lockheed Martin for Aegis research and development, and houses not only Navy and Lockheed Martin personnel, but personnel from numerous subcontractors, such as Mission Solutions Engineering and Northrop Grumman.  The New Jersey Historic Preservation Office has declared the Vice Admiral James H. Doyle, Jr. Combat System Engineering Development Site eligible for listing in the New Jersey Register of Historic Places.

Formally commissioned in 1977, it is a Navy-owned building, staffed by Navy personnel attached to Aegis Technical Representative (AEGIS TECHREP), which is an  Echelon 3 field activity under Naval Sea Systems Command (NAVSEA).

Because the facility is plainly visible from Interstate 295 and the New Jersey Turnpike, it has become something of a landmark for local residents and travelers. Area residents frequently refer to it as the "Cornfield Cruiser" or "Cruiser in a Cornfield."

An AN/SPY-1 antenna array damaged in the USS Cole bombing was later refurbished and installed in CSEDS.

Naval Facilities Engineering Command completed a large extension to the original building in early 2015.

In 2020, an AN/SPY-6(V)1 array was installed at the Combat System Engineering Development Site to support testing.

References

External links 
 USS Rancocas No Sea Sickness
Informational page, Lockheed Martin website

 
Systems command installations of the United States Navy
Buildings and structures in Burlington County, New Jersey
Military installations in New Jersey
Moorestown, New Jersey
Mount Laurel, New Jersey
Lockheed Martin
Buildings and structures completed in 1958
Light Serviços de Eletricidade. Light Serviços de Eletricidade S.A. is an electric company based in Rio de Janeiro, Brazil. It is controlled by Rio Minas Energia Participações S.A.

The company was privatized by the Brazilian federal government in 1996 when it was bought by a consortium of Houston Industries, AES Corp, and Électricité de France for US$1.7 billion. In 2006, 78.4% stake was bought by Rio Minas Energia Participações S.A.

History 
Electrical power infrastructure in Rio de Janeiro was originally developed in the first half of the 20th century by the Rio de Janeiro Tramway, Light and Power Company, a company financed with foreign capital and legally domiciled in Toronto, Canada.  After 1912, this company was part of the holding company Brazilian Traction, Light and Power Company (usually known in Brazil simply as "Light"), which eventually changed its name to Brascan (for "Brasil" + "Canada").  In 1979, the company's Brazilian assets transferred to Brazilian ownership.  The Canadian company, which had in the meantime diversified to other areas, still exists under the name Brookfield Asset Management.

References

External links 

 

Electric power companies of Brazil
Companies based in Rio de Janeiro (city)
Global Telecommunications System. The Global Telecommunication System (GTS) is a secured communication network enabling real-time exchange of meteorological data from weather stations, satellites and numerical weather prediction centres, providing critical meteorological forecasting, warnings, and alerts. It was established by the World Meteorological Organization in 1951 under the World Weather Watch programme for the free and open exchange of meteorological information.

The GTS consists of an integrated network of point-to-point circuits, and multi-point circuits which interconnect meteorological telecommunication centres. The circuits of the GTS are composed of a combination of terrestrial and satellite telecommunication links. They comprise point-to-point circuits, point-to-multi-point circuits for data distribution, multi-point-to-point circuits for data collection, as well as two-way multi-point circuits. Meteorological Telecommunication Centres are responsible for receiving data and relaying it selectively on GTS circuits. The GTS is organized on a three level basis:

 The Main Telecommunication Network (MTN)
 The Regional Meteorological Telecommunication Networks (RMTNs)
 The National Meteorological Telecommunication Networks (NMTNs)

Satellite-based data collection and/or data distribution systems are integrated in the GTS as an essential element of the global, regional and national levels of the GTS. Data collection systems operated via geostationary or near-polar orbiting meteorological/environmental satellites, including the Argos System, are widely used for the collection of observational data from data collection platforms. Marine data are also collected through the International Maritime Mobile Service and Inmarsat satellites.

References

Further reading
WMO (2013) Manual on the Global Telecommunications System WMO publication 386

External links 
 WMO's Global Telecommunication System
 WMO's GTS Community Site

1951 establishments
Telecommunications-related introductions in the 1950s
Meteorological data and networks
Data collection satellites
Pseudo-LRU. Pseudo-LRU or PLRU is a family of cache algorithms which improve on the performance of the Least Recently Used (LRU) algorithm by replacing values using approximate measures of age rather than maintaining the exact age of every value in the cache.

PLRU usually refers to two cache replacement algorithms: tree-PLRU and bit-PLRU.

Tree-PLRU

Tree-PLRU is an efficient algorithm to select an item that most likely has not been accessed very recently, given a set of items and a sequence of access events to the items.

This technique is used in the CPU cache of the Intel 486 and in many processors in the PowerPC family, such as Freescale's PowerPC G4 used by Apple Computer.

The algorithm works as follows: consider a binary search tree for the items in question. Each node of the tree has a one-bit flag denoting "go left to insert a pseudo-LRU element" or "go right to insert a pseudo-LRU element". To find a pseudo-LRU element, traverse the tree according to the values of the flags. To update the tree with an access to an item N, traverse the tree to find N and, during the traversal, set the node flags to denote the direction that is opposite to the direction taken.

This algorithm can be sub-optimal since it is an approximation. For example, in the above diagram with A, C, B, D cache lines, if the access pattern was: C, B, D, A, on an eviction, B would be chosen instead of C. This is because both A and C are in the same half and accessing A directs the algorithm to the other half that does not contain cache line C.

Bit-PLRU

Bit-PLRU stores one status bit for each cache line.  These bits are called MRU-bits. Every access to a line sets its MRU-bit to 1, indicating that the
line was recently used. Whenever the last remaining 0 bit of a set's status bits is
set to 1, all other bits are reset to 0. At cache misses, the leftmost line whose MRU-bit is 0 is replaced.

See also
 Cache algorithms

References
 https://people.cs.clemson.edu/~mark/464/p_lru.txt
 http://www.ipdps.org/ipdps2010/ipdps2010-slides/session-22/2010IPDPS.pdf
 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.217.3594&rep=rep1&type=pdf

Memory management algorithms