Ever more extensive computer systems are required by complex, multi-centre organisations. The distributed objectoriented systems model matches well to these requirements, combining the attractive properties of persis...
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Ever more extensive computer systems are required by complex, multi-centre organisations. The distributed objectoriented systems model matches well to these requirements, combining the attractive properties of persistent object systems with the contents addressability of the conventional relational model. The author focuses on the application of the objectoriented model in large-scale concurrent distributed database systems. In designing a really large scale and complex system such as a major healthcare application, the simplest approach is to build a model of the existing human organisation and its information systems. Fortunately, with today's technology this is also a cost/effective approach to implementation.< >
A new and developing area in human-computer interaction is that of the synthetic environment or virtual workstation. This is where an operator, wearing a display device on his head, is presented with suitable sensory ...
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A new and developing area in human-computer interaction is that of the synthetic environment or virtual workstation. This is where an operator, wearing a display device on his head, is presented with suitable sensory information simulating a desired situation. To accomplish this, aside from the complex technological problems of creating all of the appropriate sensations for the operator, methods must be found to represent the imaginary world within which he sits. At present, the most suitable candidate for handling with this problem is the object orientated programming approach. A simple introduction to this, with particular reference to this problem, is given. A current scheme for object representation is also discussed.< >
Computer based support for the animation of objectoriented formal specifications is desirable and technically feasible. This has been brought about by the arrival of new formal notation similar to Z but employing obj...
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Computer based support for the animation of objectoriented formal specifications is desirable and technically feasible. This has been brought about by the arrival of new formal notation similar to Z but employing objectoriented principles. Initial work on an animation tool set which in addition to the usual editing and type checking facilities also provides tools for developing animations, is described. Prolog code is generated by automatic translation of the formal description. This executable code can then be transformed to obtain a number of views of a specification (A.J.J. Dick et al., 1989). The tool set includes a Prolog transformation system which performs both user guided and automatic optimisation of code.< >
The IDAS project investigates the design and development of an Intelligent Documentation Advisory System (IDAS). The aim is to develop intelligent on-line technical documentation presented via hypertext and natural la...
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The IDAS project investigates the design and development of an Intelligent Documentation Advisory System (IDAS). The aim is to develop intelligent on-line technical documentation presented via hypertext and natural language generation and constructed dynamically by expert systems technology using object-oriented techniques. The IDAS being designed is targeted at users of an Automatic Test Equipment (ATE) system and aims to replace part of the current paper-based documentation. The IDAS will represent the ATE using a qualitative model at a level close to linguistic realisation and implemented in an object-oriented framework. It will then present material to the user via a hypertext interface. It is hoped to improve on standard hypertext systems, by giving responses which take account of the user's problems, skills and privilege. They are progressing towards a prototype implementation using the expert system shell Egeria.< >
The purpose of the project was to model a user-friendly workstation for inter-personal multimedia communication and explore solutions to unstructured office tasks. In particular, the project has concentrated upon the ...
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The purpose of the project was to model a user-friendly workstation for inter-personal multimedia communication and explore solutions to unstructured office tasks. In particular, the project has concentrated upon the provision of personal assistant functions within the workstation and the requirements for cooperative real time working between two or more remotely connected users. The aims and objectives were to study the working life of professionals with a view to determining the functionality required by the electronic office.< >
The authors describe an architecture for a user interface for an OODB which is general in nature, independent of variations in the details of an underlying object model, and capable of supporting a variety of user int...
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The authors describe an architecture for a user interface for an OODB which is general in nature, independent of variations in the details of an underlying object model, and capable of supporting a variety of user interface requirements. The prototype employs a default interface style based on hybrids of forms and control panels. Within this framework, a tool is built which allows users to declaratively define applications at a high-level of abstraction. Such user interface tools will be a requirement for OODBs in order to permit users to exploit their powerful data and computational models while hiding their complexity. It is also likely that such tools will permit users to specify application-specific user interface behaviour.< >
An object-oriented database (P/FDM) has been built as a natural extension of Shipman's functional data model (FDM) which is itself founded on entity-relationship concepts. The authors are using this (P.H.D. Gray e...
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An object-oriented database (P/FDM) has been built as a natural extension of Shipman's functional data model (FDM) which is itself founded on entity-relationship concepts. The authors are using this (P.H.D. Gray et al., 1990), to store 50 Mb of protein structure data, including the coordinates of every atom in over 80 proteins. The database is mainly used to search for fragments of protein backbone that are of interest, either because of their shape, or because of their relationship to other substructures (helices, sheets, loops). It also has a completely general query language (Daplex) which is founded on set-abstraction, list comprehensions and functions. It can call out to functions which may do arbitrary computations, combined with database search and updates. Most of the database system is written in compiled Prolog; this calls to C routines which access UNIX file structures. The Daplex language is compiled into Prolog and one can also write complex searches directly in Prolog.< >
objective-C can be regarded as a hybrid between C and Smalltalk. It was designed by Brad Cox in the early 1980s in order to bring the power of the object-oriented approach into the realm of large scale software develo...
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objective-C can be regarded as a hybrid between C and Smalltalk. It was designed by Brad Cox in the early 1980s in order to bring the power of the object-oriented approach into the realm of large scale software development. The emphasis of the language is on those aspects which most assist reusability and hence productivity. It is supported by comprehensive class libraries which are modelled on those provided by Smalltalk. The language and associated libraries are outlined.< >
objectorientedprogramming and parallel programming are two important and evolving areas in computer science. Much research has been carried out in each of the two programming disciplines, but little effort has been ...
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objectorientedprogramming and parallel programming are two important and evolving areas in computer science. Much research has been carried out in each of the two programming disciplines, but little effort has been put on combining the two areas. The authors discuss a major problem of parallel programming: synchronization of concurrent processes using a shared object. Discussing the example of the bounded buffer, they demonstrate how to build a high structured shared object based on primitive constructs in an objectoriented manner. They use the objectorientedprogramming environment Smalltalk-80 which supports basic process management and synchronization tools (semaphores). The ideas presented were realized in a prototype of a distributed directory service according to the CCIT X.500 standard.< >
object-oriented technologies are rapidly making a substantial impact on the design and engineering of many kinds of software system. Their success is motivated by the increasingly widespread recognition that a complet...
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object-oriented technologies are rapidly making a substantial impact on the design and engineering of many kinds of software system. Their success is motivated by the increasingly widespread recognition that a complete and correct specification of requirements for a large software system cannot be articulated in advance. The techniques of object-orientedprogramming particularly support software re-use and system evolution, and thereby promise to provide a solution by allowing systems to be built incrementally, capturing requirements in parallel with the development of abstractions, frameworks and partial implementation. The paper proposes explains basic object-oriented terminology and concepts. Static and dynamic aspects of the object model are introduced and illustrated, with observations about how objects are constructed, what their properties are, how they are used, and how they are related.< >
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