Introduces flexible organizations (FORS), a design environment based on a network representation of a design. Components of the design network; Provision of icon based interface; Use of the system in the mechanical de...
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Introduces flexible organizations (FORS), a design environment based on a network representation of a design. Components of the design network; Provision of icon based interface; Use of the system in the mechanical design of car window regulators.
This paper gives a formal specification of three base Avalon/C++ classes; recoverable, atomic, and subatomic. Programmers derive from class recoverable to define persistent objects, and from either class atomic or cla...
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This paper gives a formal specification of three base Avalon/C++ classes; recoverable, atomic, and subatomic. Programmers derive from class recoverable to define persistent objects, and from either class atomic or class subatomic to define atomic objects. The specifications, written in Larch, provide the means for showing that classes derived from the base classes implement objects that are persistent or atomic, and thus exemplify the applicability of an existing specification method to specifying 'nonfunctional' properties. Writing these format specifications for Avalon/C++'s built-in classes has helped to clarify places in the programming language where features interact, to make unstated assumptions explicit, and to characterize complex properties of objects. [ABSTRACT FROM AUTHOR]
Flexible Manufacturing Systems play an important role in improving our manufacturing productivity. Simulation is emerging as a popular tool in modeling FMS for analyzing its performance in the area of production plann...
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Flexible Manufacturing Systems play an important role in improving our manufacturing productivity. Simulation is emerging as a popular tool in modeling FMS for analyzing its performance in the area of production planning/scheduling. In this paper, we illustrate how to model a Flexible Manufacturing System in the object-oriented paradigm using an example. We present a systemtic approach to the design of object-oriented programming systems based on a combination of data modeling and event analysis techniques. An entity relationship approach is used as the basis for an initial decomposition of the system into objects. The design is refined by an analysis of the events the objects participate in. The design is implemented in objective-C. Finally, we describe ways in which this model of an FMS can be extended to explore popular research questions in production planning and scheduling.
This paper explores the benefits of prototyping object-oriented simulation models in a symbolic programming language. After a brief description of the project's motivation the main characteristics of object orient...
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This paper explores the benefits of prototyping object-oriented simulation models in a symbolic programming language. After a brief description of the project's motivation the main characteristics of object orientation as a programming methodology are discussed within the context of the Scheme programming language. This is followed by a description of the Canterbury Flavour System (C-Flavours), with particular emphasis on how coroutine methods are used to support process-oriented modelling styles. A characterization of architecture and usage of a typical queueing networks simulator then serves to demonstrate C-Flavours' utility for this class of applications. The paper concludes with a brief summary of related research activities in this area and some general comments on the merits of object orientation for the construction of modelling systems and simulators.
Different semantic models are studied for a language called POOL: parallel object-oriented language. It is a simplified version of POOL-T, a language that is actually used to write programs for a parallel machine. The...
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Different semantic models are studied for a language called POOL: parallel object-oriented language. It is a simplified version of POOL-T, a language that is actually used to write programs for a parallel machine. The most important aspect of this language is that it describes a system as a collection of communicating objects that all have internal activities which are executed in parallel. For POOL, operational and denotational semantics have been developed previously. The former aims at the intuitive operational meaning of the language, whereas the main characteristic of the latter is compositionality. In this paper, the author relates both models, which are quite different, and proves the semantic correctness of the denotational semantics with respect to the operational semantics. These semantic investigations take place in the mathematical framework of complete metric spaces. For the operational semantics a simple space of functions from states to compact sets of streams (which are sequences of states) is used; for the denotational semantics, a domain of processes is used, which is the solution of a reflexive domain equation over a category of complete metric spaces. The main mathematical tool we use is Banach’s theorem, which states that contractions on complete metric spaces have unique fixed points. Both the operational and the denotational semantics are reformulated and are presented, as well as many operators on the semantic domains, as the fixed point of a suitably defined contraction. In this way, a formal equivalence between both models is established. For this purpose, an intermediate domain, which is first compared to the operational model by means of an abstraction operator, is introduced. This function takes processes, which are treelike structures, as arguments and yields sets of streams as results. Next, it is shown that both intermediate and the denotational model are fixed points of the same contraction, from which their equ
The Garnet research project, which is creating a set of tools to aid the design and implementation of highly interactive, graphical, direct-manipulation user interfaces, is discussed. Garnet also helps designers rapid...
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The Garnet research project, which is creating a set of tools to aid the design and implementation of highly interactive, graphical, direct-manipulation user interfaces, is discussed. Garnet also helps designers rapidly develop prototypes for different interfaces and explore various user-interface metaphors during early product design. It emphasizes easy specification of object behavior, often by demonstration and without programming. Garnet contains a number of different components grouped into two layers. The Garnet Toolkit (the lower layer) supplies the object-oriented graphics system and constraints, a set of techniques for specifying the objects' interactive behavior in response to the input devices, and a collection of interaction techniques. On top of the Garnet Toolkit layer are a number of tools to make creating user interfaces easier. The components of both layers are described
Artificial intelligence techniques promise significant advantages in discrete simulation modelling. In particular object-oriented programming offers the possibility of mapping simulated entities onto programme objects...
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Artificial intelligence techniques promise significant advantages in discrete simulation modelling. In particular object-oriented programming offers the possibility of mapping simulated entities onto programme objects, so that class inheritance simplifies definition of similar, non-identical entities. A generalised object-oriented discrete simulation environment recently released as a commercial product provides an efficient model-building interface, comprehensive analysis facilities, and the capability of observing and modifying model behaviour during execution. However more important benefits are firstly that by specialising standard objects any desired complexity can be added to the environment, and secondly that a complex subsystem model can be defined as a composite object and included in higher level simulations. Such composites may also be replicated, either exactly or with some modification in the same or other simulations. This latter facility also offers the possibility of replacement of a subsystem model by a representative metamodel, where the performance of a composite representing part of a modelled system may be analysed so that a statistical model object can replace the composite, thus enhancing model performance. The commercial product is designed for general application, so standard object classes are designed to supply a generic range of functionality, and are named to reflect their function. The intention is that the process of specialisation can be used to modify the behaviour and nomenclature of standard classes to suit particular application needs, whilst more complex functionality, normally only used recurrently within an application area, can be provided by creation of composite object classes. Libraries containing both specialisations and composites are then constructed. Such libraries can be loaded into the programming environment to facilitate modelling in the specific application area. The methods of communication between objects defined
This paper presents a Model Builder for generating inspectable qualitative models of distribution networks. An implemented example in the domain of power distribution systems is described. The research is an extended ...
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This paper describes the architecture, capabilities and implementation of The Clockworks, an object-oriented computer animation system encompassing a wide variety of modeling, image synthesis, animation, programming a...
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An object-oriented language is being developed as an extension to an existing rule-based expert system shell. The existing shell is embedded in a distributed control system. Being embedded, it reduces hardware cost an...
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An object-oriented language is being developed as an extension to an existing rule-based expert system shell. The existing shell is embedded in a distributed control system. Being embedded, it reduces hardware cost and communication bottlenecks. object orientation dramatically increases the expressability of the language. The shell handles the procedural programming tasks so the knowledge base developer does not need to. The use of the language is demonstrated for an oil movement expert system. objects describe the physical plant. objects also describe aore abstract entities such as potential routes of oil through the pipes of the physical plant. A search method is used to generate potential routings and to recommend the good ones. The language is designed to be natural so that a process, instrumentation, operations, or plant management expert can develop an expert system. directly without either learning advanced programming skills or requiring the services of a "knowledge engineer."
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