An Abductive Approach for Analysing Event-Based Requirements Specifications

Abstract

Abstract. We present a logic and logic programming based approach for analysing event-based requirements specifications given in terms of a system's reaction to events and safety properties. The approach uses a variant of Kowalski and Sergot's Event Calculus to represent such specifications declaratively and an abductive reasoning mechanism for analysing safety properties. Given a system description and a safety property, the abductive mechanism is able to identify a complete set of counterexamples (if any exist) of the property in terms of symbolic "current" states and associated event-based transitions. A case study of an automobile cruise control system specified in the SCR framework is used to illustrate our approach. The technique described is implemented using existing tools for abductive logic programming.

Automated Error-Detection and Repair for Compositional Software Specifications

“…Several authors have proposed using logic programming to reason about software behaviour described in other formalisms [1,2,25].…”

“…Further, the formalism and semantics used here allow the modelling of concurrency without the need to introduce special actions explicitly in the language (e.g., 'tick' actions in [19]), removing one threat to scalability. The work in [25] for generating Event Calculus logic programs from descriptions expressed in a tabular specification language and applying abductive logic programming to discover violations to a restricted class of invariants, namely 'single-state' invariants. That work finds a restricted class of violations, and cannot repair specifications.…”

A goal-based approach to policy refinement

“…Since its initial presentation [4], a number of variations of the Event Calculus have been presented in the literature [6]. In this work we use the form presented in [7], consisting of (i) a set of time points (that can be mapped to the non-negative integers); (ii) a set of properties that can vary over the lifetime of the system, called fluents; and (iii) a set of event types. In addition the language includes a number of base predicates, initiates, terminates, holdsAt, happens, which are used to define some auxiliary predicates; and domain independent axioms.…”

Using event calculus to formalise policy specification and analysis

“…Since its initial presentation [6], a number of variations of the Event Calculus have been presented in the literature [11]. In this work we use the form presented in [12], consisting of (i) a set of time points (that can be mapped to the non-negative integers); (ii) a set of properties that can vary over the lifetime of the system, called fluents; and (iii) a set of event types. In addition the language includes a number of base predicates, initiates, terminates, holdsAt, happens, which are used to define some auxiliary predicates; and domain independent axioms.…”

“…The work described in [12] outlines how abduction can be used in conjunction with Event Calculus to analyse requirements specifications and presents a specialised set of Event Calculus axioms that reduce the computational complexity of the abductive proof procedure.…”