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Specification Language
A specification language is a formal language in computer science used during systems analysis, requirements analysis, and systems design to describe a system at a much higher level than a programming language, which is used to produce the executable code for a system.Joseph Goguen "One, None, A Hundred Thousand Specification Languages" Invited Paper, IFIP Congress 1986 pp 995-1004 Overview Specification languages are generally not directly executed. They are meant to describe the ''what'', not the ''how''. Indeed, it is considered as an error if a requirement specification is cluttered with unnecessary implementation detail. A common fundamental assumption of many specification approaches is that programs are modelled as algebraic or model-theoretic structures that include a collection of sets of data values together with functions over those sets. This level of abstraction coincides with the view that the correctness of the input/output behaviour of a program takes precedence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formal Language
In logic, mathematics, computer science, and linguistics, a formal language consists of words whose letters are taken from an alphabet and are well-formed according to a specific set of rules. The alphabet of a formal language consists of symbols, letters, or tokens that concatenate into strings of the language. Each string concatenated from symbols of this alphabet is called a word, and the words that belong to a particular formal language are sometimes called ''well-formed words'' or ''well-formed formulas''. A formal language is often defined by means of a formal grammar such as a regular grammar or context-free grammar, which consists of its formation rules. In computer science, formal languages are used among others as the basis for defining the grammar of programming languages and formalized versions of subsets of natural languages in which the words of the language represent concepts that are associated with particular meanings or semantics. In computational complexity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Z Notation
The Z notation is a formal specification language used for describing and modelling computing systems. It is targeted at the clear specification of computer programs and computer-based systems in general. History In 1974, Jean-Raymond Abrial published "Data Semantics". He used a notation that would later be taught in the University of Grenoble until the end of the 1980s. While at EDF ( Électricité de France), working with Bertrand Meyer, Abrial also worked on developing Z. The Z notation is used in the 1980 book ''Méthodes de programmation''. Z was originally proposed by Abrial in 1977 with the help of Steve Schuman and Bertrand Meyer. It was developed further at the Programming Research Group at Oxford University, where Abrial worked in the early 1980s, having arrived at Oxford in September 1979. Abrial has said that Z is so named "Because it is the ultimate language!" although the name "Zermelo" is also associated with the Z notation through its use of Zermelo–Fraenkel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Language Of Temporal Ordering Specification
In computer science Language Of Temporal Ordering Specification (LOTOS) is a formal specification language based on temporal ordering of events. LOTOS is used for communications protocol specification in International Organization for Standardization (ISO) Open Systems Interconnection model (OSI) standards. LOTOS is an algebraic language that consists of two parts: a part for the description of data and operations, based on abstract data types, and a part for the description of concurrent processes, based on process calculus. Work on the standard was completed in 1988, and it was published as ISO 8807 in 1989. Between 1993 and 2001, an ISO committee worked to define a revised version of the LOTOS standard, which was published in 2001 as E-LOTOS. See also * Formal methods * List of ISO standards * CADP * E-LOTOS * Process calculus In computer science, the process calculi (or process algebras) are a diverse family of related approaches for formally modelling concurrent systems. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alloy (specification Language)
In computer science and software engineering, Alloy is a declarative specification language for expressing complex structural constraints and behavior in a software system. Alloy provides a simple structural modeling tool based on first-order logic. Alloy is targeted at the creation of ''micro-models'' that can then be automatically checked for correctness. Alloy specifications can be checked using the Alloy Analyzer. Although Alloy is designed with automatic analysis in mind, Alloy differs from many specification languages designed for model-checking in that it permits the definition of infinite models. The Alloy Analyzer is designed to perform finite scope checks even on infinite models. The Alloy language and analyzer are developed by a team led by Daniel Jackson at the Massachusetts Institute of Technology in the United States. History and influences The first version of the Alloy language appeared in 1997. It was a rather limited object modeling language. Succeeding it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfect Developer
Perfect Developer (PD) is a tool for developing computer programs in a rigorous manner. It is used to develop applications in areas including IT systems and airborne critical systems. The principle is to develop a formal specification and refine the specification to code. Even though the tool is founded on formal methods, the suppliers claim that advanced mathematical knowledge is not a prerequisite. PD supports the Verified Design by Contract paradigm, which is an extension of Design by contract. In Verified Design by Contract, the contracts are verified by static analysis and automated theorem proving, so that it is certain that they will not fail at runtime. The Perfect specification language used has an object-oriented style, producing code in programming languages including Java, C# and C++. It has been developed by the UK company ''Escher Technologies Ltd''. They note on their website that their claim is not that the language itself is perfect, but that it can be used to p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TLA+
TLA+ is a formal specification language developed by Leslie Lamport. It is used for designing, modelling, documentation, and verification of programs, especially concurrent systems and distributed systems. TLA+ is considered to be exhaustively-testable pseudocode, and its use likened to drawing blueprints for software systems; ''TLA'' is an acronym for Temporal Logic of Actions. For design and documentation, TLA+ fulfills the same purpose as informal technical specifications. However, TLA+ specifications are written in a formal language of logic and mathematics, and the precision of specifications written in this language is intended to uncover design flaws before system implementation is underway. Since TLA+ specifications are written in a formal language, they are amenable to finite model checking. The model checker finds all possible system behaviours up to some number of execution steps, and examines them for violations of desired invariance properties such as safety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Attempto Controlled English
Attempto Controlled English (ACE) is a controlled natural language, i.e. a subset of standard English with a restricted syntax and restricted semantics described by a small set of construction and interpretation rules. It has been under development at the University of Zurich since 1995. In 2013, ACE version 6.7 was announced. ACE can serve as knowledge representation, specification, and query language, and is intended for professionals who want to use formal notations and formal methods, but may not be familiar with them. Though ACE appears perfectly natural – it can be read and understood by any speaker of English – it is in fact a formal language. ACE and its related tools have been used in the fields of software specifications, theorem proving, text summaries, ontologies, rules, querying, medical documentation and planning. Here are some simple examples: # Every woman is a human. # A woman is a human. # A man tries-on a new tie. If the tie pleases his wife then the man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ANSI/ISO C Specification Language
The ANSI/ISO C Specification Language (ACSL) is a specification language for C programs, using Hoare style pre- and postconditions and invariants, that follows the design by contract paradigm. Specifications are written as C annotation comments to the C program, which hence can be compiled with any C compiler. The current verification tool for ACSL is Frama-C. It also implements a sister language, ANSI/ISO C++ Specification Language (ACSL++), defined for C++. Overview In 1983, the American National Standards Institute (ANSI) commissioned a committee, X3J11, to standardize the C language. The first standard for C was published by ANSI. Although this document was subsequently adopted by International Organization for Standardization (ISO) and subsequent revisions published by ISO have been adopted by ANSI, the name ANSI C continues to be used. ACSL is a Behavioral Interface Specification Language (BISL). It aims at specifying behavioral properties of C source code. The main i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automated Theorem Prover
Automated theorem proving (also known as ATP or automated deduction) is a subfield of automated reasoning and mathematical logic dealing with proving mathematical theorems by computer programs. Automated reasoning over mathematical proof was a major impetus for the development of computer science. Logical foundations While the roots of formalised logic go back to Aristotle, the end of the 19th and early 20th centuries saw the development of modern logic and formalised mathematics. Frege's ''Begriffsschrift'' (1879) introduced both a complete propositional calculus and what is essentially modern predicate logic. His ''Foundations of Arithmetic'', published 1884, expressed (parts of) mathematics in formal logic. This approach was continued by Russell and Whitehead in their influential ''Principia Mathematica'', first published 1910–1913, and with a revised second edition in 1927. Russell and Whitehead thought they could derive all mathematical truth using axioms and inference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Program Correctness
In theoretical computer science, an algorithm is correct with respect to a specification if it behaves as specified. Best explored is ''functional'' correctness, which refers to the input-output behavior of the algorithm (i.e., for each input it produces an output satisfying the specification). Within the latter notion, ''partial correctness'', requiring that ''if'' an answer is returned it will be correct, is distinguished from ''total correctness'', which additionally requires that an answer ''is'' eventually returned, i.e. the algorithm terminates. Correspondingly, to prove a program's total correctness, it is sufficient to prove its partial correctness, and its termination. The latter kind of proof (termination proof) can never be fully automated, since the halting problem is undecidable. For example, successively searching through integers 1, 2, 3, … to see if we can find an example of some phenomenon—say an odd perfect number—it is quite easy to write a par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematical Proof
A mathematical proof is an inferential argument for a mathematical statement, showing that the stated assumptions logically guarantee the conclusion. The argument may use other previously established statements, such as theorems; but every proof can, in principle, be constructed using only certain basic or original assumptions known as axioms, along with the accepted rules of inference. Proofs are examples of exhaustive deductive reasoning which establish logical certainty, to be distinguished from empirical arguments or non-exhaustive inductive reasoning which establish "reasonable expectation". Presenting many cases in which the statement holds is not enough for a proof, which must demonstrate that the statement is true in ''all'' possible cases. A proposition that has not been proved but is believed to be true is known as a conjecture, or a hypothesis if frequently used as an assumption for further mathematical work. Proofs employ logic expressed in mathematical symbols ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
