Choreographic Programming

	Choreographic Programming In computer science, choreographic programming is a programming paradigm where programs are compositions of interactions among multiple concurrent participants. Overview Choreographies In choreographic programming, developers use a choreographic programming language to define the intended communication behaviour of concurrent participants. Programs in this paradigm are called choreographies. Choreographic languages are inspired by security protocol notation (also known as "Alice and Bob" notation). The key to these languages is the communication primitive, for example Alice.expr -> Bob.x reads "Alice communicates the result of evaluating the expression expr to Bob, which stores it in its local variable x". Alice, Bob, etc. are typically called roles or processes. The example below shows a choreography for a simplified single sign-on (SSO) protocol based on a Central Authentication Service (CAS) that involves three roles: * Client, which wishes to obtain an access token fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Computer Science Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical disciplines (including the design and implementation of Computer architecture, hardware and Computer programming, software). Computer science is generally considered an area of research, academic research and distinct from computer programming. 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 for preventing Vulnerability (computing), security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Progr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Adaptation (computer Science) The term “adaptation” in computer science refers to a process where an interactive system (adaptive system) adapts its behaviour to individual users based on information acquired about its user(s) and its environment. Adaptation is one of the three pillars of empiricism in Scrum. The need for adaptation A software system passes through a potentially long software engineering cycle and before delivery, requirement engineers, designers and software developers realize the components of the system. However, it is impossible to anticipate the requirements of all users, and a single best or optimal system configuration is impossible. The active involvement of users and clear understanding of user and task requirements is a challenge in the development of computer-based interactive systems for two reasons: * The potential user groups may not be known at the start of the project, and would need to be identified according to future scenarios of how the software system will be used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Multitier Programming Multitier programming (or tierless programming) is a programming paradigm for distributed software, which typically follows a multitier architecture, physically separating different functional aspects of the software into different ''tiers'' (e.g., the client, the server and the database in a Web application). Multitier programming allows functionalities that span multiple of such tiers to be developed in a single compilation unit using a single programming language. Without multitier programming, tiers are developed using different languages, e.g., JavaScript for the Web client, PHP for the Web server and SQL for the database. Multitier programming is often integrated into general-purpose languages by extending them with support for distribution. Concepts from multitier programming were pioneered by the Hop and Links languages and have found industrial adoption in solutions such as Ocsigen, Opa,Rajchenbach-Teller, D., & Sinot, Franois-Régis. (2010). Opa: Language support for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Structured Concurrency Structured concurrency is a programming paradigm aimed at improving the clarity, quality, and development time of a computer program by using a structured approach to concurrent programming. The core concept is the encapsulation of concurrent threads of execution (here encompassing kernel and userland threads and processes) by way of control flow constructs that have clear entry and exit points and that ensure all spawned threads have completed before exit. Such encapsulation allows errors in concurrent threads to be propagated to the control structure's parent scope and managed by the native error handling mechanisms of each particular computer language. It allows control flow to remain readily evident by the structure of the source code despite the presence of concurrency. To be effective, this model must be applied consistently throughout all levels of the program – otherwise concurrent threads may leak out, become orphaned, or fail to have runtime errors correctly propaga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Service Choreography Service choreography in business computing is a form of service composition in which the interaction protocol between several partner services is defined from a global perspective. The idea underlying the notion of service choreography can be summarised as follows: "Dancers dance following a global scenario without a single point of control" That is, at run-time each participant in a service choreography executes its part according to the behavior of the other participants. A choreography's role specifies the expected messaging behavior of the participants that will play it in terms of the sequencing and timing of the messages that they can consume and produce. Choreography describes the sequence and conditions in which the data is exchanged between two or more participants in order to meet some useful purpose. Service choreography and service orchestration Service choreography is better understood through the comparison with another paradigm of service composition: service orch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Sequence Diagram A sequence diagram or system sequence diagram (SSD) shows process interactions arranged in time sequence in the field of software engineering. It depicts the processes involved and the sequence of messages exchanged between the processes needed to carry out the functionality. Sequence diagrams are typically associated with use case realizations in the 4+1 architectural view model of the system under development. Sequence diagrams are sometimes called event diagrams or event scenarios. For a particular scenario of a use case, the diagrams show the events that external actors generate, their order, and possible inter-system events. All systems are treated as a black box; the diagram places emphasis on events that cross the system boundary from actors to systems. A system sequence diagram should be done for the main success scenario of the use case, and frequent or complex alternative scenarios. Key elements of sequence diagram A sequence diagram shows, as parallel vertical lines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Security Protocol Notation In cryptography, security (engineering) protocol notation, also known as protocol narrations and Alice & Bob notation, is a way of expressing a protocol of correspondence between entities of a dynamic system, such as a computer network. In the context of a formal model, it allows reasoning about the properties of such a system. The standard notation consists of a set of principals (traditionally named Alice, Bob, Charlie, and so on) who wish to communicate. They may have access to a server S, shared keys K, timestamps T, and can generate nonces N for authentication purposes. A simple example might be the following: :A\rightarrow B:\_ This states that Alice intends a message for Bob consisting of a plaintext X encrypted under shared key KA,B. Another example might be the following: :B\rightarrow A:\_ This states that Bob intends a message for Alice consisting of a nonce NB encrypted using public key of Alice. A key with two subscripts, KA,B, is a symmetric key Symmetric-ke ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Proof Assistant In computer science and mathematical logic, a proof assistant or interactive theorem prover is a software tool to assist with the development of formal proofs by human-machine collaboration. This involves some sort of interactive proof editor, or other interface, with which a human can guide the search for proofs, the details of which are stored in, and some steps provided by, a computer. System comparison * ACL2 – a programming language, a first-order logical theory, and a theorem prover (with both interactive and automatic modes) in the Boyer–Moore tradition. * Coq – Allows the expression of mathematical assertions, mechanically checks proofs of these assertions, helps to find formal proofs, and extracts a certified program from the constructive proof of its formal specification. * HOL theorem provers – A family of tools ultimately derived from the LCF theorem prover. In these systems the logical core is a library of their programming language. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Proof Assistant In computer science and mathematical logic, a proof assistant or interactive theorem prover is a software tool to assist with the development of formal proofs by human-machine collaboration. This involves some sort of interactive proof editor, or other interface, with which a human can guide the search for proofs, the details of which are stored in, and some steps provided by, a computer. System comparison * ACL2 – a programming language, a first-order logical theory, and a theorem prover (with both interactive and automatic modes) in the Boyer–Moore tradition. * Coq – Allows the expression of mathematical assertions, mechanically checks proofs of these assertions, helps to find formal proofs, and extracts a certified program from the constructive proof of its formal specification. * HOL theorem provers – A family of tools ultimately derived from the LCF theorem prover. In these systems the logical core is a library of their programming language. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Java (programming Language) Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let programmers ''write once, run anywhere'' ( WORA), meaning that compiled Java code can run on all platforms that support Java without the need to recompile. Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of the underlying computer architecture. The syntax of Java is similar to C and C++, but has fewer low-level facilities than either of them. The Java runtime provides dynamic capabilities (such as reflection and runtime code modification) that are typically not available in traditional compiled languages. , Java was one of the most popular programming languages in use according to GitHub, particularly for client–server web applications, with a reported 9 million developers. Java was originally developed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Microservices A microservice architecture – a variant of the service-oriented architecture structural style – is an architectural pattern that arranges an application as a collection of loosely-coupled, fine-grained services, communicating through lightweight protocols. One of its goals is that teams can develop and deploy their services independently of others. This is achieved by the reduction of several dependencies in the code base, allowing for developers to evolve their services with limited restrictions from users, and for additional complexity to be hidden from users. As a consequence, organizations are able to develop software with fast growth and size, as well as use off-the-shelf services more easily. Communication requirements are reduced. These benefits come at a cost to maintaining the decoupling. Interfaces need to be designed carefully and treated as a public API. One technique that is used is having multiple interfaces on the same service, or multiple versions of the sam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Session Type In type theory, session types are used to ensure correctness in concurrent programs. They guarantee that messages sent and received between concurrent programs are in the expected order and of the expected type. Session type systems have been adapted for both channel and actor systems. Session types are used to ensure desirable properties in concurrent and distributed systems, i.e. absence of communication errors or deadlocks, and protocol conformance. Binary versus Multiparty Session Types Interaction between two processes can be checked using ''binary'' session types, while interactions between more than two processes can be checked using ''multiparty'' session types. In multiparty session types interactions between all participants are described using a ''global type'', which is then projected into ''local types'' that describe communication from the local view of each participant. Importantly, the global type encodes the sequencing information of the communication, which wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]