omniomni/omni-engineering huggingface dataset:
Cyclic/collective pitch mixing. Cyclic/collective pitch mixing (CCPM) is a control concept employed in collective pitch radio-controlled helicopters. CCPM reduces mechanical complexity and increases precision of control of the helicopter rotor's swashplate. Unlike conventional systems in which a single actuator is responsible for a single axis, CCPM mechanisms allow multiple actuators to work together to manipulate all axis of control.

Conventional operation 
Older model helicopters use three independent servos to manipulate the swashplate. The elevator servo is used to tilt the swashplate forward and aft (longitudinal cyclic), varying the aircraft's pitch. The aileron servo is used to tilt the swashplate left and right (lateral cyclic), varying the aircraft's roll. The collective pitch servo raises and lowers the entire swashplate, varying the collective, and hence the pitch of all the rotor blades collectively. An intermediate mechanical mixing system is used to transfer the control inputs from the servos to the swashplate, therefore the name of mechanical CCPM (mCCPM). This requires an elaborate system of control rods and levers, which often contains many ball bearings.

Electronic mixing 
To reduce the mechanical complexity, newer model helicopters use a software system (usually running on the transmitter) to mix the control inputs of three interdependent servos to control the swashplate. The three servo linkages are arranged around the swashplate at 120° intervals (there is a variation that uses 140° + 140° + 80° intervals). In addition to lower mechanical complexity, the interdependent servos share the workload.

An evolution of electronic mixing is the advent of flight controllers, otherwise known as "flybarless systems". Flybarless systems provide two key benefits to model helicopters. By removing the mechanical flybar from the rotorhead, there is less mass and lower aerodynamic drag resulting in improved efficiency. The accelerometers in the flybarless system also provide electronic stabilisation, allowing for finer levels of tuning and greater flight characteristics.

See also 
 Anatomy of a helicopter
 Helicopter flight controls
 Aeronautical engineering

References

External links 
 RC Heli Flight School

Miniature helicopters
Wind Erosion on European Light Soils. WEELS ("Wind Erosion on European Light Soils") was a research project funded as part of the EU Environment and Climate Programme, intended to develop a small-scale model of wind erosion at the level of individual farms and fields, based on research at three test sites in Lower Saxony, Scania, and Suffolk.

WEELS was a collaborative project between University College London, the Geological Survey of Lower Saxony (Niedersächsisches Landesamt für Bodenforschung) at the Institute of Soil Technology, Bremen, Lund University, and Wageningen University. It ran from 1997 to 2000.

External links 
http://www.dow.wau.nl/eswc/research/weels1.html 

WEELS final report , as downloadable pdf files

Pedology
Conservation in England
Nature conservation in Germany
Nature conservation in Sweden
Lower Saxony
Scania
University College London
Lund University
Wageningen University and Research
Context (computing). In computer science, a task context is the minimal set of data used by a task (which may be a process, thread, or fiber) that must be saved to allow a task to be interrupted, and later continued from the same point. The concept of context assumes significance in the case of interruptible tasks, wherein, upon being interrupted, the processor saves the context and proceeds to serve the interrupt service routine. Thus, the smaller the context is, the smaller the latency is.

The context data may be located in processor registers, memory used by the task, or in control registers used by some operating systems to directly manage the task.

The storage memory (files used by a task) is not concerned by the "task context" in the case of a context switch, even if this can be stored for some uses (checkpointing).

The context can also be viewed as a mechanism that allows a state of a program to be transferred between its components.

Context types
In some computer languages like C#, there is also the concept of safe/secure context. For instance, if an array is needed inside a structure, it can be added to it since version 2.0, but only in an unsafe/unsecure context. Here is an example code:

struct ParameterRepresentation
{
    char target;
    char taskStart;
    char taskType;
    fixed byte traceValues[m_MAX_BYTES];
};

The fixed keyword prevents the garbage collector from relocating this variable. The access to an array is like in C++, i.e. using pointer arithmetic, where individual elements of the array can be accessed over its indices.

See also
 State (computer science)
 Context and Adaptivity in Pervasive Computing Environments: Links with Software Engineering and Ontological Engineering, article in Journal of Software, Vol 4, No 9 (2009), 992-1013, Nov 2009 by Ahmet Soylu, Patrick De Causmaecker and Piet Desmet

References

External links 
 Context S-Cube Knowledge Model

Process (computing)
Mundic. Mundic was used from the 1690s to describe a copper ore that began to be smelted at Bristol and elsewhere in southwestern Britain.  Smelting was carried out in cupolas, that is reverberatory furnaces using mineral coal.   For more details, see copper extraction.

Mundic once referred to pyrite, but has now adopted the wider meaning of concrete deterioration caused by oxidisation of pyrites within the aggregate (usually originating from mine waste). The action of water and oxygen on pyrite forms sulphate (a salt of sulphuric acid), thereby depleting the pyrite, causing loss of adhesion and physical expansion.

Mundic block problem
The Cornish word mundic is now used to describe a cause of deterioration in concrete due to the decomposition of mineral constituents within the aggregate. A typical source of such aggregates is metalliferous mine waste. RICS Professional guidance describes all of Cornwall and an area within 15 km of Tavistock as being areas where routine testing for mundic is required. The notes go on to state that testing should be confined to buildings which contain concrete elements (blocks or in situ) and that were built in or prior to 1950. However, the notes contain advice that testing may be required where there are visual or other signs of mundic decay. Testing leads to a classification of A (subdivided into A1, A2 and A3), B or C. All A classifications are sound, B is sound but contains sufficient deleterious aggregate for it to be considered unstable and C is unsound. Classifications B & C mean that a property may be unmortgageable.

Typically a house is routinely screened if constructed between 1900 and 1960 from concrete block.

References

Building materials
Cornish language
Mining in Cornwall
Eagle (application server). EAGLE is a Web-based, mainframe-powered application server which provides direct, secure, high performance Internet access to mainframe computer data and transactions using real-time transaction processing rather than middleware or external gateways.

Originally based in an IBM 3270 environment developed at the University of Florida to reduce the delivery time of student record applications, the engine was configured for the Web in 1996 and removed the need for a screen scraping interface.

What EAGLE does

EAGLE provides direct network access to mainframe data and transactions. Web applications talk directly to native mainframe resources without the complexity or expense of middleware. Non-mainframe resources can be accessed via hooks to customized communication programs, using XML or EDI.

Since EAGLE is itself a mainframe computer transaction, application pages are created internally and delivered via the Web. This reduces overhead compared to external call interfaces resulting in considerable performance gains; during periods of peak demand at the University of Florida, EAGLE routinely handles 400,000 transactions per day while maintaining sub-second response time.

Session management

The Web is defined as a stateless environment—normally, a Web page is requested, the Web page is delivered, and the interaction is over. EAGLE associates pages with a user and handles authentication and authorization.  The EAGLE session management engine is protected behind mainframe security.

Current and Former EAGLE implementations 

 University of Florida
 Office of the University Registrar (ISIS and ISISAdmin)
 Student Financial Affairs
 Student Activities (Gator Nights)
 Illinois State University
 Shands Health Care
 FACTS.org (Florida Academic Counseling and Tracking for Students)
 FACTS Central Site was created as an EAGLE application

EAGLE patent 

EAGLE was awarded patent 6,532,463 for its state maintenance mechanism.

External links
 EAGLE home page 
 FACTS.org
 ISIS home page at UF

Web server software
IBM mainframe software
ESDU. ESDU (originally an acronym of "Engineering Sciences Data Unit" but now used on its own account)  is an engineering advisory organisation based in the United Kingdom.

Profile 
ESDU provides validated engineering analysis tools to engineers and teachers in the aerospace engineering, process engineering and structural engineering fields. The tools include methodologies, design guides, equations and software, and are accompanied by an advisory service that enables engineers to discuss their requirements and data application directly with ESDU staff.

ESDU's engineering staff are assisted and guided in their work by independent committees of specialists drawn from industry and academia worldwide. They are responsible for ensuring the technical quality of the work and for presenting the data in a clear, concise, authoritative manner. They also determine the future direction of the work, taking into account the views of users.

Engineering topics covered 
The services offered by ESDU cover a wide variety of different engineering fields. These include:
 Aerodynamics 
 Aircraft noise
 Composite materials
 Dynamics
 Fatigue
 Fracture Mechanics
 Fluid Mechanics
 Heat Transfer
 Mechanisms
 Aircraft Performance
 Physical Data, Chemical Engineering
 Physical Data, Mechanical Engineering
 Process Engineering Technology
 Sound Propagation
 Stress and Strength of Components
 Structures
 Transonic Aerodynamics
 Tribology 
 Vibration and Acoustic Fatigue
 Wind Engineering

History 
In 1940 with World War II raging the British aircraft industry was rapidly expanding. Engineers from other industries as diverse as bicycle manufacture and piano making who lacked the specialised knowledge required for aircraft design were being drafted into the war effort to assist with the design and construction of aircraft.

To meet this challenge, the government asked the Royal Aeronautical Society to form a Technical Department with the aim of producing easy-to-use design guides, data sheets and analysis methodologies. More importantly the Technical Department was to validate this work to ensure its accuracy. To ensure the authority and quality of the work, a Technical Committee was established, with its expert members drawn from across the many aircraft companies and research establishments. In short, ESDU were tasked with bridging the gap between research and industry. This unique philosophy of collaboration allowed the team to assemble a large collection of validated design guides and data sheets for use by the aircraft industry.

Towards the end of the 1960s, grant aid was withdrawn and ESDU became a commercial entity selling subscriptions to its services. In 1998 ESDU was purchased by IHS Inc. based in Denver, United States, which, in turn became part of S&P Global. In 2023 S&P Global spun off its Engineering Solutions division, which includes ESDU, as a newly formed company called Accuris.

References

External links
 ESDU
 IHS Inc.
 Accuris
 Royal Aeronautical Society
 S&P spins off Accuris

Engineering companies of the United Kingdom
Bill Tritt. Bill Tritt (August 29, 1917 - March 25, 2011) was an American yacht builder.

He began working in Glass-reinforced plastic in 1948. He founded Glasspar Corporation in 1949 due to his keen interest in boats and cars and his belief in fiberglass as a material.

Before the World War II, he studied marine architecture and boat building.

He worked for Douglas Aircraft's Production Planning and Illustration Departments during World War II, and by 1945 had built a number of catamaran sailboats. In 1947, John Green, a yachtsman friend, paid Tritt to design and build a racing sailboat in the twenty foot range. Fiberglass-reinforced plastic (FRP) seemed the logical construction material, and Otto Bayer of Wizard Boats was enlisted as laminator. The boat was named the Green Dolphin, and four were built. This was Tritt's introduction to FRP.

Boats 
By 1947 he was building small fiberglass boats, and built the first ever fiberglass masts and spars for sailboats. This company became the Glasspar Company and moved to larger quarters in Santa Ana, California, in the early 1950s. By the mid-1950s, Glasspar was producing fifteen to twenty percent of all fiberglass boats sold in the United States. About this time Tritt incorporated and offered stock to generate working capital.

Cars 
Tritt also designed and built car bodies (one of the first to do so in fiberglass) as well as speedboat and runabout hulls. Tritt is credited with designing and building the first production fiberglass car called the G2. During this period he also designed and or built bodies for Blanchard Robert "Woody" Woodill, Strassberger Motor Company, British Singer Car Company, Willys, Kaiser (when Kaiser bought out Willys), Volvo, and Walt Disney.  He may also have had a hand in helping GM determine the best way to fabricate fiberglass bodies for its new line of cars the Corvette. With the successes of these car bodies Tritt decided to design and build a complete sports car called the Ascot, but the Glasspar board of directors voted this down in favor of concentrating on the core business of boat building.

Recently one of Bill Tritt's G2 cars was enshrined in the Smithsonian Institution as the first production fiberglass car.

References

External links
G2 at Hemmings Motor News
Glasspar at Coachbuilt.com
LaDawri (and a few others!) at LaDawri.com

American chief executives
American yacht designers
1917 births
2011 deaths
Access control matrix. In computer science, an access control matrix or access matrix is an abstract, formal security model of protection state in computer systems, that characterizes the rights of each subject with respect to every object in the system. It was first introduced by Butler W. Lampson in 1971.

An access matrix can be envisioned as a rectangular array of cells, with one row per subject and one column per object. The entry in a cell – that is, the entry for a particular subject-object pair – indicates the access mode that the subject is permitted to exercise on the object. Each column is equivalent to an access control list for the object; and each row is equivalent to an access profile for the subject.

Definition
According to the model, the protection state of a computer system can be abstracted as a set of objects , that is the set of entities that needs to be protected (e.g. processes, files, memory pages) and a set of subjects , that consists of all active entities (e.g. users, processes). Further there exists a set of rights  of the form , where ,  and . A right thereby specifies the kind of access a subject is allowed to process object.

Example
In this matrix example there exist two processes, two assets, a file, and a device. The first process is the owner of asset 1, has the ability to execute asset 2, read the file, and write some information to the device, while the second process is the owner of asset 2 and can read asset 1.

Utility
Because it does not define the granularity of protection mechanisms, the Access Control Matrix can be used as a model of the static access permissions in any type of access control system. It does not model the rules by which permissions can change in any particular system, and therefore only gives an incomplete description of the system's access control security policy.

An Access Control Matrix should be thought of only as an abstract model of permissions at a given point in time; a literal implementation of it as a two-dimensional array would have excessive memory requirements. Capability-based security and access control lists are categories of concrete access control mechanisms whose static permissions can be modeled using Access Control Matrices. Although these two mechanisms have sometimes been presented (for example in Butler Lampson's Protection paper) as simply row-based and column-based implementations of the Access Control Matrix, this view has been criticized as drawing a misleading equivalence between systems that does not take into account dynamic behaviour.

See also
 Access control list (ACL)
 Capability-based security
 Computer security model
 Computer security policy

References

 

Computer security models
Computer access control
Hyderabad Electric Supply Company. Hyderabad Electric Supply Company (HESCO; ) is an electric distribution company that supplies electricity to the southern districts of Sindh in Pakistan, excluding Karachi.

Current CEO of the company is Mr. Bashir Ahmed.

Formation of the company
Hyderabad had an Area Electricity Board (AEB) as one of the eight AEBs constituted through amendments in WAPDA Act during 1981. Later on, as the Government of Pakistan approved the revamping of the Water and Power Development Authority (WAPDA) power sector in April 1998, the Hyderabad Electric Supply Company took over responsibilities of the Hyderabad Area Electricity Board. Hyderabad Electric Supply Company is owned and operated by WAPDA though. The company was incorporated on 23 April 1998 and certificate for commencement of business was obtained on 1 July 1998 from NEPRA under section 146(2) of Companies Ordinance 1984.

As a result of revamping, 12 corporate entities, 8 distribution companies (DISCOs), 3 generation companies (GENSCOs) and 1 National Transmission and Dispatch Company  (NTDC) company were formed. Under 8 DISCOs, Area Electricity Board (AEB) Hyderabad was one of them. Therefore, HESCO - Hyderabad Electric Supply Company came in to formation. Formerly known as Area Electricity Board (AEBH) Hyderabad.

See also 

 List of electric supply companies in Pakistan

References

External links
 Hyderabad Electric Supply Company

Distribution companies of Pakistan
Hyderabad District, Pakistan
Government-owned companies of Pakistan
Marcus Nanotechnology Building. The Marcus Nanotechnology Building (MNB) is a Georgia Institute of Technology facility. The building was constructed on the site of the Electronics Research Building, the former home of GTRI's Information and Communications Laboratory. It was opened on April 24, 2009, as the Marcus Nanotechnology Research Center, a name it held until October 2013.

Research
The Marcus Nanotechnology Building (MNB) is now the headquarters for the Institute of Electronics and Nanotechnology (IEN), one of Georgia Tech's several new Interdisciplinary Research Institutes (IRI). In addition to being the headquarters for the IEN, the building houses the largest cleanroom laboratory dedicated to the fabrication, characterization, and assembly of biomedical and semiconductor devices in the Southeast United States.

These shared-user open laboratories are part of the National Science Foundation's National Nanotechnology Infrastructure Network (NNIN), a network of 14 such facilities at universities around the US. The laboratories are available to global academics, industry and government personnel on a fee recovery basis enabling students, scientists and engineers who perform research on nanotechnology to study the characteristics and behavior of atoms and molecules, and to use that knowledge to create new materials and tiny nano-scale tools and machines.

Status
The Information and Communications Laboratory was previously located on the site, and has been moved to GCATT. The Electronics Research Building, established in 1966, was demolished, and construction began in Fall 2006/Spring 2007.

The construction was funded by several donations, including $7 million from the State of Georgia, $15 million from the Marcus Foundation, and $36 million from an anonymous source.

References

External links 

Georgia Tech buildings and structures
Leadership in Energy and Environmental Design certified buildings
University and college laboratories in the United States
Stressed ribbon bridge. A stressed ribbon bridge (also stress-ribbon bridge or catenary bridge) is a tension structure similar in many ways to a simple suspension bridge. The suspension cables are embedded in the deck, which follows a catenary arc between supports. As with a simple suspension bridge, the weight is taken by the suspension cables, but unlike the simple span, the deck or ribbon is stressed in compression, which adds to the stiffness of the structure (simple suspension spans tend to sway and bounce). The supports in turn sustain upward-thrusting arcs that allow the grade to be changed between spans (where multiple spans are used). Such bridges are typically made from concrete reinforced by steel tensioning cables. Where such bridges carry vehicle traffic, a certain degree of stiffness is required to prevent excessive flexure of the structure, obtained by stressing the concrete in compression.

Examples

 Leonel Viera Bridge, Uruguay - the first stressed ribbon bridge ever built. Designed and built by engineer Lionel Viera. Completed in 1965. In 1999 a twin bridge was built 20 meters (65 ft) upstream to accommodate two-way traffic.
 Lake Hodges Pedestrian Bridge, California - the longest stressed ribbon bridge in the world, measuring .
 Phyllis J. Tilley Memorial Bridge - a hybrid concrete arch/stressed ribbon bridge across the Trinity River in Fort Worth, Texas.
 Rogue River Pedestrian Bridge - a pedestrian-pipeline bridge across the Rogue River at Grants Pass, Oregon.
 Terwillegar Park Footbridge - a stressed ribbon bridge across the North Saskatchewan River in Edmonton, Alberta, that is the second longest in the world, measuring .
 Langur Way Canopy Walk - located in The Habitat atop Penang Hill in Penang, Malaysia, this is the world’s highest-altitude stressed ribbon bridge (740m above sea level) as well as being the only one in a tropical rainforest.

Notes

References

External links

 List of stressed ribbon bridges, Structurae
 Structurae: Image of one of the two Maldonado stressed ribbon bridges
 Tourist article containing a reference to the above bridge (the Maldonado bridge)
 Spanish language site concerning the works of Don Leonel Viera

Bridges by structural type
Reverse telnet. Reverse telnet is a specialized application of telnet, where the server side of the connection reads and writes data to a computer terminal line (RS-232 serial port), rather than providing a command shell to the host device.  Typically, reverse telnet is implemented on an embedded device (e.g. terminal/console server), which has an Ethernet network interface and serial port(s).  Through the use of reverse telnet on such a device, IP-networked users can use telnet to access serially-connected devices.  

In the past, reverse telnet was typically used to connect to modems or other external asynchronous devices. Today, reverse telnet is used mostly for connecting to the console port of a router, a switch or other device.

Example
On the client, the command line for initiating a "reverse telnet" connection might look like this: 

telnet 172.16.1.254 2002

(The syntax in the above example would be valid for the command-line telnet client packaged with many operating systems, including most Unix operating systems, or available as an option or add-on.)

In this example, 172.16.1.254 is the IP address of the console device, and 2002 is the TCP port associated with a terminal line on the server.

See also
 Terminal server
 Console server

Internet protocols
Internet Protocol based network software
Telnet
Unix network-related software
Out-of-band management