To achieve the termination of offline partial evaluation, it is necessary to ensure that static variables assume boundedly many values during specialization. Various works have addressed the analysis of variable boundedness, also called finiteness analysis, in the context of specializing first-order functional programs. The underlying reasoning is always: Observing arbitrarily many increases in a static variable during specialization must be impossible, if that would imply observing arbitrarily long sequences of size decreases among some bounded-variable values. Static analysis is used...

... this paper, we combine these two ideas and demonstrate their power by presenting an interpreter, written in Prolog, for a variant of Golog that is suitable for eciently operating in open-world setting by exploiting sensing and bounded lookahead.

. This paper addresses the problem of ensuring that agents' plans are epistemically feasible in multiagent systems specifications. We propose some solutions within the CASL formalism. We define a subjective execution construct Subj that causes the plan to be executed in terms of the agent's knowledge state rather than in therms of the world state. The definition assumes that the agent does not do planning or lookahead and chooses arbitrarily among the actions allowed by the plan. We also define another deliberative execution operator Delib for smarter agents that do planning. We show how these notions can be used to express whether a plan is epistemically feasible for an agent in several types of situations. 1

Expressions in the programming language C have such an under-specified semantics that one might expect them to be non-deterministic. However, with the help of a mechanised formalisation, we have shown that the semantics’ additional constraints actually result in a large class of C expressions having only one possible behaviour.

The thesis investigates some of the traditional problems with the established formal methods, such as requirements elicitation, the validation problem, divergence from current industrial practice, adverse effects on early problem solving and the incompleteness of perspective. Recent approaches to solving some of these problems are reviewed, including structured and formal methods integration, hybrid formal methods and multi-paradigmed approaches. The definition of a method first used by Kronlof is adopted and two reasons for integrating methods are hypothesised: ffl The integration of methods which result in a richer methodological profile, such as methods which address different stages of the life-cycle, and; ffl The integration of methods which result in a wider overall perspective, and are thus effective over a wider number of prospective problems, such as methods which consider different orthogonal aspects of requirements. Two pieces of work are then presented, one for each hypot...

We give an operational semantics for the synchronisation mechanisms of µDemos, a process-oriented discrete event simulation language based upon Simula and Demos. ¯Demos contains several classic synchronisation mechanisms: mutual-exclusion, producer/consumer, and process rendezvous. The operational semantics gives a clear, concise and precise meaning to these constructs and may be used to reason about µDemos programs, to guide an implementation, and as a pedagogical tool to aid understanding. It may also be used as a basis for comparisons with other semantics bases (e.g. the more abstract denotational semantics), formal checking of the properties of simulation models, and meta-level abstractions over synchronisations to ensure their consistency.

Bruns has proposed a version of value-passing CCS in which an agent language, based on that proposed by Milner, is augmented with a rich data language. The data language can be used to describe sets, tuples and sequences etc. constructed from integer, boolean and string constants. Z is a widely used formal specification language in which sets, tuples and sequences can be described, but also additional constructs such as free types and bindings. In addition, Z has a rich structuring mechanism -- its schema calculus. Z is frequently used to specify the operations of a system on its state, and has a refinement calculus and formal semantics. This article introduces ZCCS, a version of value-passing CCS in which the data language used to describe the action /agent parameters and conditions is Z. We introduce the style and syntax of ZCCS and illuminate this with a small example. In addition, we present an operational semantics for ZCCS. 1 Introduction When Milner defined value-passing CCS ...

this paper -- an office coffee-delivery robot might be implemented as an infinite loop in which the robot responds to exogenous requests for coffee that are maintained on a queue. Since a future coffee request is always possible, the program never terminates. As is the case for more conventional programs, we want some reliability assurances for robot controllers. This paper describes the approach being taken by our Cognitive Robotics Group to expressing and proving properties of non-terminating programs expressed in GOLOG, a high level logic programming language for modeling and implementing dynamical systems. The kinds of properties we have in mind are traditional in computer science: liveness, fairness, etc. We differ from the "classical" approaches ([LS87, Cou90, MP95]) for reasons dictated by the following characteristics of GOLOG: 1. To write a GOLOG program, the programmer first axiomatizes the primitive actions of the application domain, using first order logic. These actions may also include exogenous events. 2. Next, she describes, in GOLOG, the complex behaviors her robot is to exhibit in this domain. This GOLOG program is interpreted by means of a formula, this time in second order logic. 3. Finally, a suitable theorem-prover executes the program. Because these features are all represented in classical (second order) logic, it is natural to express and prove properties of GOLOG programs, including non-terminating ones, in the very same logic. This approach to program proofs has the advantage of logical uniformity and the availability of classical proof theory. It also provides a very rich language with which to express program properties, as we shall see in this paper. Moreover, it provides for proofs of programs with incomplete initial state, the normal situ...

This report considers the problem of interpreting behavioural meanings from model-based specifications written in formal specification languages such as Z, VDM-SL or AMN. It contends that certain requirements -- such as the order in which operations are invoked, the origin, destination, and ordering (together with the implied presence) of inputs and outputs -- significant in certain problem domains, are difficult to express within the established approaches. In the light of this discussion we promote an approach that combines the expressive powers of both process algebras and model-based approaches for the modelling of systems with a pronounced behavioural perspective as well as significant emphasis on data and process requirements. As a first step toward an integrated language involving Z and CCS, a language, ZCCS, is presented -- a dialect of value-passing CCS that employs Z as its value-calculus. The (abstract) syntax of the language is defined and a small example of a ZCCS specific...

{ blazy, facon} @ i ie.cnam.fr This paper describes a tool for facilitating the comprehension of general programs using automatic specialization. The goal of this approach was to assist in the maintenance of old programs, which have become very complex due IO numerous extensions. This paper explains why this approach was chosen, how the tool's architecture was set up, and how the correctness of the specialization has been proved. Then, we discuss the results obtained by using this tool, and the future evolutions. 1.