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Eiffel is an object-oriented programming language designed by Bertrand Meyer and Eiffel Software. Meyer conceived the language in 1985 with the goal of increasing the reliability of commercial software development; the first version becoming available in 1986. In 2005, Eiffel became an ISO-standardized language.
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In computer programming, an infinite loop is a sequence of instructions that, as written, will continue endlessly, unless an external intervention occurs. It may be intentional.
In computer science, control flow is the order in which individual statements, instructions or function calls of an imperative program are executed or evaluated. The emphasis on explicit control flow distinguishes an imperative programming language from a declarative programming language.
Verilog, standardized as IEEE 1364, is a hardware description language (HDL) used to model electronic systems. It is most commonly used in the design and verification of digital circuits at the register-transfer level of abstraction. It is also used in the verification of analog circuits and mixed-signal circuits, as well as in the design of genetic circuits. In 2009, the Verilog standard was merged into the SystemVerilog standard, creating IEEE Standard 1800-2009. Since then, Verilog has been officially part of the SystemVerilog language. The current version is IEEE standard 1800-2023.
A state diagram is a type of diagram used in computer science and related fields to describe the behavior of systems. State diagrams require that the system described is composed of a finite number of states; sometimes, this is indeed the case, while at other times this is a reasonable abstraction. Many forms of state diagrams exist, which differ slightly and have different semantics.
In computer programming, specifically when using the imperative programming paradigm, an assertion is a predicate connected to a point in the program, that always should evaluate to true at that point in code execution. Assertions can help a programmer read the code, help a compiler compile it, or help the program detect its own defects.
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The Guarded Command Language (GCL) is a programming language defined by Edsger Dijkstra for predicate transformer semantics in EWD472. It combines programming concepts in a compact way. It makes it easier to develop a program and its proof hand-in-hand, with the proof ideas leading the way; moreover, parts of a program can actually be calculated.
In concurrent programming, a monitor is a synchronization construct that prevents threads from concurrently accessing a shared object's state and allows them to wait for the state to change. They provide a mechanism for threads to temporarily give up exclusive access in order to wait for some condition to be met, before regaining exclusive access and resuming their task. A monitor consists of a mutex (lock) and at least one condition variable. A condition variable is explicitly 'signalled' when the object's state is modified, temporarily passing the mutex to another thread 'waiting' on the conditional variable.
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Vandana "Vandi" Verma is a space roboticist and chief engineer at NASA's Jet Propulsion Laboratory, known for driving the Mars rovers, notably Curiosity and Perseverance, using software including PLEXIL programming technology that she co-wrote and developed.
A spacecraft command language is a computer command language for commanding spacecraft mission systems. Ultimately such languages are used to command remote spacecraft with telecommands, but they are also used for development and verification of onboard systems, and of ground systems, prior to launch.
SpaceXCrew Dragon In-Flight Abort Test was a successful test of the SpaceX Dragon 2 abort system, conducted on 19 January 2020. It was the final assessment for the Crew Dragon capsule and Falcon 9 launch system before they would be certified to carry humans into space. Booster B1046.4 and an uncrewed capsule C205 were launched from Launch Complex 39A (LC-39A) on a suborbital trajectory, followed by an in-flight abort of the capsule at max Q and supersonic speed. The test was carried out successfully: the capsule pulled itself away from the booster after launch control commanded the abort, and landed safely.
References
- ↑ Estlin, Tara; Jonsson, Ari; Pasareanu, Corina; Simmons, Reid; Tso, Kam; Verma, Vandi (April 2006). "Plan Execution Interchange Language (PLEXIL)" (PDF). NASA Technical Reports Server. Retrieved 8 February 2019.
- ↑ "Bibliography of PLEXIL-related publications, organized by category". Plexil souceforge. Retrieved 8 February 2019.
- ↑ "Main page: NASA applications". PLEXIL sourceforge. Retrieved 8 February 2019.
- ↑ "PLEXIL (Plan execution software)".