Constrained expressions: Adding analysis capabilities to design methods for concurrent software systems

Abstract

We describe an approach to the design of concurrent software systems based on the constrained expression formalism. This formalism provides a rigorous conceptual model for the semantics of concurrent computations, thereby supporting analysis of important system properties as part of the design process. At the same time, our approach allows designers to use standard specification and design languages, rather than forcing them to deal with the formal model explicitly or directly. As a result, our approach attains the benefits of formal rigor without the associated pain of unnatural concepts or notations for its users.The conceptual model of concurrency underlying the constrained expression formalism treats the collection of possible behaviors of a concurrent system as a set of sequences of events. The constrained expression formalism provides a useful closed-form description of thesesequences. We have developed algorithms for translating designs expressed in a wide variety of notations into these constrained expression descriptions. We have also developed a number of powerful analysis techniques that can be applied to these descriptions.In this paper, we describe the constrained expression formalism and these analysis techniques. We then describe the way this approach would be used in design, giving an example illustrating its use in conjunction with an Ada-like design language, and discuss present and future prospects for its automation and use.

Foundations for the study of software architecture

“…J sic properties must be explicitly described. A number of notations exist that are suitable for making such descriptions, including parallel path expressions [6], constrained expressions [1], and petri nets [16]. In this example we use parallel path expressions, where a comma indicates sequence, a plus sign indicates one or more repetitions, an asterisk indicates zero or more repetitions, and subexpressions are enclosed in parentheses.…”

Real-time software methodologies: Are they suitable for developing Manufacturing control software?

“…The system expression is a regular expression over an augmented alphabet derived from a description of the system. The constraints may be thought of as imposing requirements on a sequence of events that must be satisfied if the sequence is to occur in a behavior of the system (Avrunin et al 1986). In DPMS, the structure of a dynamically structured distributed system can be altered either by adding or deleting processes or by adding or deleting interprocess communication channels.…”

Automated Analysis of Concurrent and Real-Time Software

“…Detailed and rigorous presentations of the formalism appear in [12] and in the appendix to [14], while less formal treatments intended to provide a more intuitive understanding of the features of the formalism appear in [7] and [4]. The use of constrained expressions with a variety of development notations is illustrated in [7] and [14].…”

“…Detailed and rigorous presentations of the formalism appear in [12] and in the appendix to [14], while less formal treatments intended to provide a more intuitive understanding of the features of the formalism appear in [7] and [4]. The use of constrained expressions with a variety of development notations is illustrated in [7] and [14]. A detailed discussion of the relation between constrained expressions and a variety of other methods for describing and analyzing concurrent software systems can be found in [7] and [17].…”

“…The use of constrained expressions with a variety of development notations is illustrated in [7] and [14]. A detailed discussion of the relation between constrained expressions and a variety of other methods for describing and analyzing concurrent software systems can be found in [7] and [17].…”