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Clock Constraints Specification Language
The Clock Constraint Specification Language or CCSL, is a software language for modeling relations among so-called clocks. It is part of the time model defined in the UML Profile for MARTE. CCSL provides a concrete syntax to handle logical clocks. The term logical clock refers to Leslie Lamport's logical clocks and its usage in CCSL is directly inspired from Synchronous programming languages (like Esterel or Signal). A solver A solver is a piece of mathematical software, possibly in the form of a stand-alone computer program or as a software library, that 'solves' a mathematical problem. A solver takes problem descriptions in some sort of generic form and calculates t ... of CCSL constraints is implemented in the TimeSquare tool. References Time Unified Modeling Language {{time-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Modeling And Analysis Of Real Time And Embedded Systems
Modeling and Analysis of Real Time and Embedded systems also known as MARTE is the OMG standard for modeling real-time and embedded applications with UML2. Description The UML modeling language has been extended by the OMG consortium to support model-driven development of real-time and embedded application. This extension has been defined via a UML2 profile called MARTE (Modeling and Analysis of Real-Time and Embedded systems). It consists mainly of four parts: * a core framework defining the basic concepts required to support real-time and embedded domain. * a first specialization (refinement) of this core package to support pure modeling of applications (e.g. hardware and software platform modeling). * a second specialization (refinement) of this core package to support quantitative analysis of UML2 models, specially schedulability and performance analysis. * a last part gathering all the MARTE annexes such as the one defining a textual language for value specification within ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logical Clock
A logical clock is a mechanism for capturing chronological and causal relationships in a distributed system. Often, distributed systems may have no physically synchronous global clock. In many applications (such as distributed GNU make), if two processes never interact, the lack of synchronization is unobservable and in these applications it is enough for the processes to agree on the event ordering (i.e., logical clock) rather than the wall-clock time. The first logical clock implementation, the Lamport timestamps, was proposed by Leslie Lamport in 1978 ( Turing Award in 2013). Local vs global time In logical clock systems each process has two data structures: ''logical local time'' and ''logical global time''. Logical local time is used by the process to mark its own events, and logical global time is the local information about global time. A special protocol is used to update logical local time after each local event, and logical global time when processes exchange data. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leslie Lamport
Leslie B. Lamport (born February 7, 1941 in Brooklyn) is an American computer scientist and mathematician. Lamport is best known for his seminal work in distributed systems, and as the initial developer of the document preparation system LaTeX and the author of its first manual. Lamport was the winner of the 2013 Turing Award for imposing clear, well-defined coherence on the seemingly chaotic behavior of distributed computing systems, in which several autonomous computers communicate with each other by passing messages. He devised important algorithms and developed formal modeling and verification protocols that improve the quality of real distributed systems. These contributions have resulted in improved correctness, performance, and reliability of computer systems. Early life and education Lamport was born into a Jewish family in Brooklyn, New York, the son of Benjamin and Hannah Lamport (née Lasser). His father was an immigrant from Volkovisk in the Russian Empire (now Vawka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchronous Programming Language
A synchronous programming language is a computer programming language optimized for programming reactive systems. Computer systems can be sorted in three main classes: (1) transformational systems that take some inputs, process them, deliver their outputs, and terminate their execution; a typical example is a compiler; (2) interactive systems that interact continuously with their environment, at their own speed; a typical example is the web; and (3) reactive systems that interact continuously with their environment, at a speed imposed by the environment; a typical example is the automatic flight control system of modern airplanes. Reactive systems must therefore react to stimuli from the environment within strict time bounds. For this reason they are often also called real-time systems, and are found often in embedded systems. Synchronous programming (also synchronous reactive programming or SRP) is a computer programming paradigm supported by synchronous programming languages. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Esterel
Esterel is a synchronous programming language for the development of complex reactive systems. The imperative programming style of Esterel allows the simple expression of parallelism and preemption. As a consequence, it is well suited for control-dominated model designs. The development of the language started in the early 1980s, and was mainly carried out by a team of Ecole des Mines de Paris and INRIA led by Gérard Berry in France. Current compilers take Esterel programs and generate C code or hardware (RTL) implementations (VHDL or Verilog). The language is still under development, with several compilers out. The commercial version of Esterel is the development environment Esterel Studio. The company that commercialize itSynfora initiated a normalization process with the IEEE in April 2007 however the working group (P1778) dissolved March 2011. ThEsterel v7 Reference Manual Version v7 30 – initial IEEE standardization proposalis publicly available. The Multiform Not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solver
A solver is a piece of mathematical software, possibly in the form of a stand-alone computer program or as a software library, that 'solves' a mathematical problem. A solver takes problem descriptions in some sort of generic form and calculates their solution. In a solver, the emphasis is on creating a program or library that can easily be applied to other problems of similar type. Solver types Types of problems with existing dedicated solvers include: * Linear and non-linear equations. In the case of a single equation, the "solver" is more appropriately called a root-finding algorithm. * Systems of linear equations. * Nonlinear systems. * Systems of polynomial equations, which are a special case of non linear systems, better solved by specific solvers. * Linear and non-linear optimisation problems * Systems of ordinary differential equations * Systems of differential algebraic equations * Boolean satisfiability problems, including SAT solvers * Quantified boolean formula solv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time
Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to compare the duration of events or the intervals between them, and to quantify rates of change of quantities in material reality or in the conscious experience. Time is often referred to as a fourth dimension, along with three spatial dimensions. Time has long been an important subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars. Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems. 108 pages. Time in physics is operationally defined as "what a clock reads". The physical nature of time is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
