Formal Specification Notation Research Articles

Adding partial functions to Constraint Logic Programming with sets

AbstractPartial functions are common abstractions in formal specification notations such as Z, B and Alloy. Conversely, executable programming languages usually provide little or no support for them. In this paper we propose to add partial functions as a primitive feature to a Constraint Logic Programming (CLP) language, namely {log}. Although partial functions could be programmed on top of {log}, providing them as first-class citizens adds valuable flexibility and generality to the form of set-theoretic formulas that the language can safely deal with. In particular, the paper shows how the {log} constraint solver is naturally extended in order to accommodate for the new primitive constraints dealing with partial functions. Efficiency of the new version is empirically assessed by running a number of non-trivial set-theoretical goals involving partial functions, obtained from specifications written in Z.

Consistency preserving co-evolution of formal specifications and agent-oriented conceptual models

Many modelling techniques tend to address “late-phase” requirements while many critical modelling decisions (such as determining the main goals of the system, how the stakeholders depend on each other, and what alternatives exist) are taken during early-phase requirements engineering. The i ∗ modelling framework is a semiformal agent-oriented conceptual modelling language that is well-suited for answering these questions. This paper addresses key challenge faced in the practical deployment of agent-oriented conceptual modelling frameworks such as i ∗. Our approach to addressing this problem is based on the observation that the value of conceptual modelling in the i ∗ framework lies in its use as a notation complementary to existing requirements modelling and specification languages, i.e., the expressive power of i ∗ complements rather than supplants that of existing notations. The use of i ∗ in this fashion requires that we define methodologies that support the co-evolution of i ∗ models with more traditional specifications. This research examines how this might be done with formal specification notations (specifically Z).

FORMAL SPECIFICATION APPROACH OF ROLE DYNAMICS IN AGENT ORGANISATIONS: APPLICATION TO THE SATISFACTION-ALTRUISM MODEL

This article deals with the problem of dynamic role-playing in Multi-Agent organisations. The approach presented uses a formal specification notation and is based upon a formal framework which defines the concepts of role, interaction and organisation. Within this framework the problem of dynamic role-playing specification is related to the merging of specifications. The formal notation used composes Object-Z and Statecharts. The main features of this approach are: enough expressive power to represent Multi-Agents dynamic aspects, tools for specification analysis and mechanisms allowing the refinement of a high level specification into a low level specification which can be easily implemented. The last part of this paper presents an application with the specification of a reactive and cooperative MAS model named Satisfaction Altruism. An analysis of the specification validates the agents' behaviours.

Temporal logic properties of Java objects

Applying finite-state verification techniques to software systems looks attractive because they are capable of detecting very subtle defects in the logic design of these systems. Nevertheless, the integration of existing formal verification tools within programming environments is not yet easy, mainly because of the semantic gap between widely used programming languages and the languages used to describe system requirements. In this paper, we propose a formal requirement specification notation based on linear temporal logic, with regard to object oriented program elements, such as classes and interfaces. The specification is inherently object oriented and is meant for the verification of concurrent and distributed software systems.

Specifying and Refining Internal Operations in Z

Abstract. An important aspect in the specification of distributed systems is the role of the internal (or unobservable) operation. Such operations are not part of the interface to the environment (i.e. the user cannot invoke them), however, they are essential to our understanding and correct modelling of the system. In this paper we are interested in the use of the formal specification notation Z for the description of distributed systems. Various conventions have been employed to model internal operations when specifying such systems in Z. If internal operations are distinguished in the specification notation, then refinement needs to deal with internal operations in appropriate ways. Using an example of a telecommunications protocol we show that standard Z refinement is inappropriate for refining a system when internal operations are specified explicitly. We present a generalisation of Z refinement, called weak refinement, which treats internal operations differently from observable operations when refining a system. We discuss the role of internal operations in a Z specification, and in particular whether an equivalent specification not containing internal operations can be found. The nature of divergence through livelock is also discussed.

Integrating a formal specification notation with HOOD

No abstract available.

Mathematical notation in formal specification: too difficult for the masses?

The phrase "not much mathematics required" can imply a variety of skill levels. When this phrase is applied to computer scientists, software engineers, and clients in the area of formal specification, the word "much" can be widely misinterpreted with disastrous consequences. A small experiment in reading specifications revealed that students already trained in discrete mathematics and the specification notation performed very poorly; much worse than could reasonably be expected if formal methods proponents are to be believed.

Formal Specification Applied to Control Systems Development

Formal software specification languages are becoming sufficiently powerful to consider their use in application domains as realistic. This paper reports on a project aiming at the application of formal specification notations and techniques in the development of real-time control applications. It puts emphasis on the development of reliable control systems by means of the integration of a formal specification notation in the controller development process. This paper discusses the application of ASTRAL (Ghezzi and Kemmerer, 1991a) for the requirements specification of a robot control system. It shows that formal specification provides a useful extension to current modelling capabilities in the application domain

A requirements sublanguage for automated analysis

The development of a restricted natural language for expressing requirements is described. the purpose of the language is to support readable specifications, which can be analyzed for errors and automatically interpreted. the specific language designed here is for specification of digital systems. Semantics are represented in a type of semantic network constructed of concepts and relations. the semantic basis, consisting of concept and relation types together with semantic patterns, is developed from an examination of several formal specification and design notations, together with a selection of natural language statements from product descriptions. the syntax of the language is developed from a syntactic analysis of natural language statements, and the productions of the grammar are selected to maximize coverage of syntactic structures used in the selection. © 1995 John Wiley & Sons, Inc.

The formal specification of abstract data types and their implementation in Fortran 90

In this paper we present an approach to the development of computational science software based on the identification and specification of Abstract Data Types and their implementation in Fortran 90. Our aim is to improve upon current standards of documentation and levels of genericity of such software, and, by the use of a formal specification notation, afford the possibility of undertaking correctness proofs. We illustrate the approach by applying it to a problem which is concerned with the construction of sets of electron configurations and their angular momentum couplings; software to solve this problem is required to enhance the Graphical R-matrix Atomic Collision Environment (G RACE) graphical user interface. In particular, we show how a formal notation can be used to specify unambigously the functionality of software components and we describe the role of the formal specification from the perspective of the ADT implementor and the ADT user. Finally we show how Fortran 90, through its derived types and module facility, directly supports the encapsulation of ADTs thereby enabling the construction of better engineered software than has hitherto been possible using Fortran.

Monitoring the Development of Real-Time Systems: the COSMOS Project

We describe the theory and use of the COSMOS static analysing tool, which has been developed under the CEC Esprit programme. The tool can be used to analyse a wide range of program languages and formal specification notations. It produces common-ground structural accounts of these documents which are then, in turn, analysed for metrication purposes. The result is a range of well-known structural product metrics, which may be used to monitor and contro] software development projects. We have placed particular emphasis on real-time telecom applications in our work and our paper concludes with an account of the preliminary results romour validation studies.