The challenge for the metaobject protocol designer is to balance the conflicting demands of efficiency, simplicity, and extensibility. It is impossible to know all desired extensions in advance; some of them will requ...
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The challenge for the metaobject protocol designer is to balance the conflicting demands of efficiency, simplicity, and extensibility. It is impossible to know all desired extensions in advance; some of them will require greater functionality, while others require greater efficiency. In addition, the protocol itself must be sufficiently simple that it can be fully documented and understood by those who need to use it. This paper presents the framework of a metaobject protocol forEuLisp which provides expressiveness by a multi-leveled protocol and achieves efficiency by static semantics for predefined metaobjects and modularizing their operations. TheEuLisp module system supports global optimizations of metaobject applications. The metaobject system itself is structured into modules, taking into account the consequences for the compiler. It provides introspective operations as well as extension interfaces for various functionalities, including new inheritance, allocation, and slot access semantics. While the overall goals and functionality are close to those of Kiczaleset al. [9], the approach shows different emphases. As a result, time and space efficiency as well as robustness have been improved.
The basic properties of object orientation and their application to heterogeneous, autonomous, and distributed system to increase interoperability ar examined. It is argued that object-oriented distributed computing i...
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The basic properties of object orientation and their application to heterogeneous, autonomous, and distributed system to increase interoperability ar examined. It is argued that object-oriented distributed computing is a natural step forward from client-server systems. To support this claim, the differing levels of object-oriented support already found in commercially available distributed systems-in particular, the distributed computing environment of the open software foundation and the Cronus system of Bolt Beranek, Newman (BBN)-are discussed. Emerging object-oriented systems and standards are described, focusing on the convergence toward a least-common-denominator approach to object-oriented distributed computing embodied by the object management group's common object request broker architecture
Fast and accurate diagnosis of faults in computer integrated manufacturing systems is essential in order to avoid excessive equipment downtime, and to take full advantage of these systems. Traditional approaches to di...
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Fast and accurate diagnosis of faults in computer integrated manufacturing systems is essential in order to avoid excessive equipment downtime, and to take full advantage of these systems. Traditional approaches to diagnosis have yielded to artificial intelligence approaches over recent years, as system complexity has increased;but results have been mixed. Symptom-based approaches have been too limited, while structural-based approaches have required excessive computational resources. This paper presents a hybrid model for diagnostics that is computationally efficient, and at the same time incorporates the potential to improve its performance with use through a learning scheme.
object-oriented programming techniques were used to develop computer based data display and storage systems. These have been operating in the 8 anaesthetising areas of the Adelaide Children's Hospital for 3 years....
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object-oriented programming techniques were used to develop computer based data display and storage systems. These have been operating in the 8 anaesthetising areas of the Adelaide Children's Hospital for 3 years. The analogue and serial outputs from an array of patient monitors are connected to IBM(TM) compatible PC-XT computers. The information is displayed on a colour screen as wave-form and trend graphs and digital format in 'real time'. The trend data is printed simultaneously on a dot matrix printer. This data is also stored for 24 hours on 'hard' disk. The major benefit has been the provision of a single visual focus for all monitored variables. The automatic logging of data has been invaluable in the analysis of critical incidents. The systems were made possible by recent, rapid improvements in computer hardware and software. This paper traces the development of the program and demonstrates the advantages of object-oriented programming techniques.
Contrary to the importance given to simulation modeling, output analysis has seen little implementation effort. Most of the simulation systems and programs have very primitive forms of output analysis facilities. This...
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Contrary to the importance given to simulation modeling, output analysis has seen little implementation effort. Most of the simulation systems and programs have very primitive forms of output analysis facilities. This might result in either statistically insignificant results, if the analyst does not have correct assumptions about the system and uses a very simple output analysis method, or it can discourage the analyst from using the methods because it will be very hard to use them without ready computer help. This paper analyzes the output analysis methods in literature and reports ways to include them in simulation environments. A generic object-oriented design for output analysis methods is also described. A critical comparison of object-oriented and traditional methods is included.
This paper describes an object-oriented architecture to support decision making in production scheduling environments. An object-oriented world view is used to integrate concepts from discrete event simulation, conven...
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This paper describes an object-oriented architecture to support decision making in production scheduling environments. An object-oriented world view is used to integrate concepts from discrete event simulation, conventional scheduling logic and artificial intelligence to produce capacity-feasible schedules. The architecture was implemented as a collection of loosely coupled reusable software objects by extending the functionality of software objects from BLOCS/M (Berkeley Library of objects for Control and Simulation of Manufacturing). Our experience with an industrial prototype is presented.
A computer-based architecture program called the Distributed and Integrated Environment for Computer-Aided Engineering (Dice), which provides cooperation and coordination among multiple designers working in separate e...
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A computer-based architecture program called the Distributed and Integrated Environment for Computer-Aided Engineering (Dice), which provides cooperation and coordination among multiple designers working in separate engineering disciplines, is described. Dice uses knowledge to estimate interface conditions between disciplines, records who used any piece of design data created by others and how such data were used, and checks for conflicts among disciplines, manufacturability, and manufacturing cost and schedule effects of design decisions
It is a challenge to support advanced applications involving multiple users in a distributed computing environment that consists of heterogeneous and autonomous resources. A distributed cooperative task in which multi...
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It is a challenge to support advanced applications involving multiple users in a distributed computing environment that consists of heterogeneous and autonomous resources. A distributed cooperative task in which multiple agents cooperate to achieve application objectives offers flexible and reliable support. Controlling interactions among the cooperating agents is a critical issue in such a paradigm. The ITX (interactive transaction) system supports complex interactions among cooperating agents in the presence Of user interventions that change application objectives and system failures. ITX supports reliable operations on shared objects (representing cooperative objectives, shared data structures, and resources) that are stored in heterogeneous and autonomous component systems. A novel application-independent criterion called fixed point defines a stable system state with respect to an agent. Agents achieve a fixed point and the application-dependent cooperative objective by using a feedback control strategy that involves iterative execution of ITXs. These ITXs consist of atomic transactions that manipulate the shared objects. The authors use a multimedia teleconferencing service to illustrate the important features and advantages of the ITX system.
The problems of data and process decomposition and representation in engineering design are the objectives of this paper. In any typical mechanical design, many very complex interdependencies are generated Interdepend...
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This paper is an abstracted version of the EuLisp definition. As such it emphasizes those parts of the language that we consider the most important or note-worthy, while we just mention, without much detail the elemen...
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