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Formal Specification
In computer science, formal specifications are mathematically based techniques whose purpose is to help with the implementation of systems and software. They are used to describe a system, to analyze its behavior, and to aid in its design by verifying key properties of interest through rigorous and effective reasoning tools. These specifications are ''formal'' in the sense that they have a syntax, their semantics fall within one domain, and they are able to be used to infer useful information. Motivation In each passing decade, computer systems have become increasingly more powerful and, as a result, they have become more impactful to society. Because of this, better techniques are needed to assist in the design and implementation of reliable software. Established engineering disciplines use mathematical analysis as the foundation of creating and validating product design. Formal specifications are one such way to achieve this in software engineering reliability as once predicted. O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Science
Computer science is the study of computation, information, and automation. Computer science spans Theoretical computer science, theoretical disciplines (such as algorithms, theory of computation, and information theory) to Applied science, applied disciplines (including the design and implementation of Computer architecture, hardware and Software engineering, software). Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of computational problem, problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and preventing security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Programming language theory considers different ways to describe computational processes, and database theory concerns the management of re ... [...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–Frae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Model-based Specification
Model-based specification is an approach to formal specification where the system specification is expressed as a system state model. This state model is constructed using well-understood mathematical entities such as sets and functions. System operations are specified by defining how they affect the state of the system model. The most widely used notations for developing model-based specifications are VDM and Z (pronounced Zed, not Zee). These notations are based on typed set theory. Systems are therefore modelled using sets and relations between sets. Another well-known approach to formal specification is algebraic specification. See also * Model-based design * Model-based testing Model-based testing is an application of model-based design for designing and optionally also executing artifacts to perform software testing or system testing. Models can be used to represent the desired behavior of a system under test (SUT), or ... References {{Reflist Formal methods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OBJ (programming Language)
OBJ is a programming language family introduced by Joseph Goguen in 1976, and further worked on by Jose Meseguer. Overview It is a family of declarative programming, declarative "ultra high-level" languages. It features Abstract data type, abstract types, generic modules, subsorts (subtypes with multiple inheritance), pattern matching, pattern-matching modulo equations, E-strategies (user control over lazy evaluation, laziness), module expressions (for combining modules), theories and views (for describing module interfaces) for the massively parallel RRM (rewrite rule machine). Members of the OBJ family of languages include CafeOBJ, Eqlog, FOOPS, Kumo (OBJ), Kumo, Maude system, Maude, OBJ2, and OBJ3. OBJ2 OBJ2 is a programming language with Clear (specification language), Clear-like parametrised modules and a functional system based on equations. OBJ3 OBJ3 is a version of OBJ based on Order theory, order-sorted rewriting. OBJ3 is Intelligent agent, agent-oriented and runs on Ky ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larch Family
The Larch family of formal specification languages are intended for the precise specification of computing systems. They allow the clean specification of computer programs and the formulation of proofs about program behavior. The Larch family was developed primarily in the United States in the 1980s and 1990s, involving researchers at Xerox PARC, DEC Systems Research Center (DEC/SRC), Massachusetts Institute of Technology (MIT), and other places. Unlike the Z notation, the Larch family has one language for algebraic specification of abstract data types (the ''Larch Shared Language'' (LSL)), and a separate ''interface language'' tailored to each language in which programs are to be written, such as C, Modula-3, Smalltalk, etc. The Larch project also developed tools to support the use of formal specifications, including the Larch Prover (LP). See also * Formal methods In computer science, formal methods are mathematics, mathematically rigorous techniques for the formal specifica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algebraic Specification
Algebraic specification is a software engineering technique for formally specifying system behavior. It was a very active subject of computer science research around 1980. Overview Algebraic specification seeks to systematically develop more efficient programs by: # formally defining types of data, and mathematical operations on those data types # abstracting implementation details, such as the size of representations (in memory) and the efficiency of obtaining outcome of computations # formalizing the computations and operations on data types # allowing for automation by formally restricting operations to this limited set of behaviors and data types. An algebraic specification achieves these goals by defining one or more data types, and specifying a collection of functions that operate on those data types. These functions can be divided into two classes: # Constructor functions: Functions that create or initialize the data elements, or construct complex elements from simpler ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quality Of Service
Quality of service (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network, or a cloud computing service, particularly the performance seen by the users of the network. To quantitatively measure quality of service, several related aspects of the network service are often considered, such as packet loss, bit rate, throughput, transmission delay, availability, jitter, etc. In the field of computer networking and other packet-switched telecommunication networks, quality of service refers to traffic prioritization and resource reservation control mechanisms rather than the achieved service quality. Quality of service is the ability to provide different priorities to different applications, users, or data Traffic flow (computer networking), flows, or to guarantee a certain level of performance to a data flow. Quality of service is particularly important for the transport of traffic with special requirements. In particula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Web Services
A web service (WS) is either: * a service offered by an electronic device to another electronic device, communicating with each other via the Internet, or * a server running on a computer device, listening for requests at a particular port over a network, serving web documents (HTML, JSON, XML, images). In a web service, a web technology such as HTTP is used for transferring machine-readable file formats such as XMLHttpRequest, XML and JSON. In practice, a web service commonly provides an Object database, object-oriented web-based interface to a database server, utilized for example by another web server, or by a Mobile app development, mobile app, that provides a user interface to the end-user. Many organizations that provide data in formatted HTML pages will also provide that data on their server as XML or JSON, often through a Web service to allow Web syndication, syndication. Another application offered to the end-user may be a Mashup (web application hybrid), mashup, where a W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abstract Machine Notation
Abstract may refer to: *"Abstract", a 2017 episode of the animated television series ''Adventure Time'' * ''Abstract'' (album), 1962 album by Joe Harriott * Abstract algebra, sets with specific operations acting on their elements * Abstract of title, a summary of the documents affecting the title to a parcel of land * Abstract (law), a summary of a legal document * Abstract (summary), in academic publishing * Abstract art, artistic works that do not attempt to represent reality or concrete subjects * '' Abstract: The Art of Design'', 2017 Netflix documentary series * Abstract music, music that is non-representational * Abstract object in philosophy * Abstract structure in mathematics * Abstract type in computer science * The property of an abstraction * Q-Tip (musician), also known as "The Abstract" * Abstract and concrete In philosophy and the arts, a fundamental distinction exists between abstract and concrete entities. While there is no universally accepted definition, commo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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''. It is considered 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 over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Divide And Conquer Algorithm
In computer science, divide and conquer is an algorithm design paradigm. A divide-and-conquer algorithm recursively breaks down a problem into two or more sub-problems of the same or related type, until these become simple enough to be solved directly. The solutions to the sub-problems are then combined to give a solution to the original problem. The divide-and-conquer technique is the basis of efficient algorithms for many problems, such as sorting (e.g., quicksort, merge sort), multiplying large numbers (e.g., the Karatsuba algorithm), finding the closest pair of points, syntactic analysis (e.g., top-down parsers), and computing the discrete Fourier transform ( FFT). Designing efficient divide-and-conquer algorithms can be difficult. As in mathematical induction, it is often necessary to generalize the problem to make it amenable to a recursive solution. The correctness of a divide-and-conquer algorithm is usually proved by mathematical induction, and its computational c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
