Formal specification

About: Formal specification is a research topic. Over the lifetime, 18383 publications have been published within this topic receiving 370652 citations.

Symbolic Model Checking

Abstract: Symbolic model checking is a powerful formal specification and verification method that has been applied successfully in several industrial designs. Using symbolic model checking techniques it is possible to verify industrial-size finite state systems. State spaces with up to 1030 states can be exhaustively searched in minutes. Models with more than 10120 states have been verified using special techniques.

A classification and comparison framework for software architecture description languages

Abstract: Software architectures shift the focus of developers from lines-of-code to coarser-grained architectural elements and their overall interconnection structure. Architecture description languages (ADLs) have been proposed as modeling notations to support architecture-based development. There is, however, little consensus in the research community on what is an ADL, what aspects of an architecture should be modeled in an ADL, and which of several possible ADLs is best suited for a particular problem. Furthermore, the distinction is rarely made between ADLs on one hand and formal specification, module interconnection, simulation and programming languages on the other. This paper attempts to provide an answer to these questions. It motivates and presents a definition and a classification framework for ADLs. The utility of the definition is demonstrated by using it to differentiate ADLs from other modeling notations. The framework is used to classify and compare several existing ADLs, enabling us, in the process, to identify key properties of ADLs. The comparison highlights areas where existing ADLs provide extensive support and those in which they are deficient, suggesting a research agenda for the future.

Goal-directed requirements acquisition

Abstract: Requirements analysis includes a preliminary acquisition step where a global model for the specification of the system and its environment is elaborated This model, called requirements model, involves concepts that are currently not supported by existing formal specification languages, such as goals to be achieved, agents to be assigned, alternatives to be negotiated, etc The paper presents an approach to requirements acquisition which is driven by such higher-level concepts Requirements models are acquired as instances of a conceptual meta-model The latter can be represented as a graph where each node captures an abstraction such as, eg, goal, action, agent, entity, or event, and where the edges capture semantic links between such abstractions Well-formedness properties on nodes and links constrain their instances-that is, elements of requirements models Requirements acquisition processes then correspond to particular ways of traversing the meta-model graph to acquire appropriate instances of the various nodes and links according to such constraints Acquisition processes are governed by strategies telling which way to follow systematically in that graph; at each node specific tactics can be used to acquire the corresponding instances The paper describes a significant portion of the meta-model related to system goals, and one particular acquisition strategy where the meta-model is traversed backwards from such goals The meta-model and the strategy are illustrated by excerpts of a university library system

The algorithmic analysis of hybrid systems

Abstract: We present a general framework for the formal specification and algorithmic analysis of hybrid systems. A hybrid system consists of a discrete program with an analog environment. We model hybrid systems as finite automata equipped with variables that evolve continuously with time according to dynamical laws. For verification purposes, we restrict ourselves to linear hybrid systems, where all variables follow piecewise-linear trajectories. We provide decidability and undecidability results for classes of linear hybrid systems, and we show that standard program-analysis techniques can be adapted to linear hybrid systems. In particular, we consider symbolic model-checking and minimization procedures that are based on the reachability analysis of an infinite state space. The procedures iteratively compute state sets that are definable as unions of convex polyhedra in multidimensional real space. We also present approximation techniques for dealing with systems for which the iterative procedures do not converge.

Software Abstractions: Logic, Language, and Analysis

Abstract: In Software Abstractions Daniel Jackson introduces an approach to software design that draws on traditional formal methods but exploits automated tools to find flaws as early as possible. This approach--which Jackson calls "lightweight formal methods" or "agile modeling"--takes from formal specification the idea of a precise and expressive notation based on a tiny core of simple and robust concepts but replaces conventional analysis based on theorem proving with a fully automated analysis that gives designers immediate feedback. Jackson has developed Alloy, a language that captures the essence of software abstractions simply and succinctly, using a minimal toolkit of mathematical notions. This revised edition updates the text, examples, and appendixes to be fully compatible with the latest version of Alloy (Alloy 4). The designer can use automated analysis not only to correct errors but also to make models that are more precise and elegant. This approach, Jackson says, can rescue designers from "the tarpit of implementation technologies" and return them to thinking deeply about underlying concepts. Software Abstractions introduces the key elements: a logic, which provides the building blocks of the language; a language, which adds a small amount of syntax to the logic for structuring descriptions; and an analysis, a form of constraint solving that offers both simulation (generating sample states and executions) and checking (finding counterexamples to claimed properties).