37577922
Non-Interference Properties of a Concurrent Object-Based Language: Proofs Based on an Operational Semantics
A carefully designed concurrent object-oriented language can provide a suitable target for a compositional design process that copes with the interference inherent with concurrency. The semantics of a particular object-based design language have been written using operational semantics and by a mapping to the first-order polyadic π-calculus. This paper focuses on the operational semantics and indicates how proofs of some key properties about interference can be based on such a definition: the final theorems prove that certain equivalences — which can be used to enhance concurrency-are sound. The limitations of the operational semantics based proofs are discussed as is the interest in transferring intuitions from these proofs to ones based on a mapping to the π-calculus.
2399941
Operational semantics: Concepts and their expression
6772552
Fixing the semantics of some concurrent object-oriented concepts
Abstract Concurrent object-oriented languages provide a suitable target for a compositional design process that copes with the interference inherent with concurrency. Fixing the semantics of an object-based design language has been undertaken using structured operational semantics and by a mapping to the pi-calculus. These two approaches are outlined and contrasted. In particular, the difficulties in the two approaches of justifying the proof rules of the proposed design method are explained.
45828501
Formal Definition in Program Development
The intent of the current paper is to show how a large problem like compiler development can be divided in a way which provides a structure for arguments of correctness. Although mechanically checked proofs are not envisaged, the use of formal notation is recommended so that the basis for correctness arguments exists.
15308825
Scientific Decisions which Characterize VDM
The formal description and development method known as VDM has been used extensively, its specification language is now an ISO standard, and it has influenced other specification languages. The origins of VDM are normally placed in language description or semantics but it is probably best known in the wider arena of formal methods for (general) program specification and design. This paper sets out a personal view of some of the key technical decisions which characterize the Vienna Development Method.
9236653
The Early Search for Tractable Ways of Reasoning about Programs
This article traces the history - up to around 1990 - of research on reasoning about programs. The main focus is on sequential imperative programs but some comments are made on concurrency. The main thesis is that the idea of reasoning about programs has been around since they were first written; the search has been to find tractable methods.
36993113
A Collaborative Schema Integration System
Conceptual modelling as applied to database development can be described as a two stage process: schema modelling followed by schema integration. Schema modelling is the process of transforming individual user requirements into a conceptual schema: an implementation-independent map of data requirements. Schema integration is the process of combining individual conceptual schemas into a single, unified schema. Single-user tools for schema modelling have enjoyed much success partly because the process of schema modelling has become relatively well formalised. Although a number of formal approaches to conducting schema integration have been proposed, it appears that schema integration tools have not enjoyed the same level of success. This we attribute not so much to the problem of formalisation but to the inherent collaborative nature of schema integration work. This paper first discusses the importance of collaboration to schema integration work. It then describes SISIBIS, a demonstrator system employing the IBIS (Issue Based Information System) scheme to support collaborative database design.
6079094
Haptic interface control-design issues and experiments with a planar device
Describes the haptic rendering of a virtual environment by drawing upon concepts developed in the area of teleoperation. A four-channel teleoperation architecture is shown to be an effective means of coordinating the control of a 3-DOF haptic interface with the simulation of a virtual dynamic environment.
205571678
A Prolog Rule-Based System for Cartographic Name Placement
Manual name placement is an extremely time consuming task and has been one of the most difficult aspects of the map production process to automate. It is complicated by the large number of rules required for the selection and placement of names. A hybrid Prolog/Fortrau rule-based system is described for placing names on a variety of map types. It uses a set of Prolog primitives for spatial search and name placement operations. The Ordnance Survey's 1:625000 scale digital dataset has been used to illustrate the application of rules for the selection of labels as well as for controlling their size and orientation. The application to other types of maps and diagrams is also briefly described.
42189866
Episodes in Space: Qualitative Representation and Reasoning Over Spatio-Temporal Objects
There is growing interest in many application domains for the temporal treatment and manipulation of spatially referenced objects. Handling the time dimension in spatial databases can greatly enhance and extend their functionality and usability by offering means of understanding the spatial behaviour in time. Few works, to date, have been directed towards the development of formalisms for representation and reasoning in this domain. In this paper, a new approach is presented for the representation and reasoning over spatio-temporal relationships. The approach is simple and aims to satisfy the requirements of coherency, expressiveness and reasoning power. Consistent behaviours of spatial objects in time are denoted episodes. The topology of the domain is defined by decomposing episodes into representative components and relationships are defined between those components. Spatio-temporal reasoning is achieved by composing the relationships between the object components using constraint networks. New composition tables between simple spatio-temporal regions and between regions and volumes are also derived and used in the reasoning process.
32895841
Software Change Management
Software projects change rapidly, which makes efficient change management a major challenge for the software industry. This challenge was poorly met for years because of rudimentary tools. The paper considers how modern change management, or configuration control tools must encompass changes affecting every kind of software deliverable and artifact.