”All animals are equal, but some animals are more equal than others”, Antrum Farm, George Orwell. Object Orientation is a current hot theme for researchers and developers of distributedsystems. This paper reviews t...
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The distributedsystems group in Trinity have been concerned with fault tolerance for a number years and are now turning our attention to the topic with renewed interest (and urgency). Specifically we are concerned to...
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Z is a software system designed to provide media-transparent net- work services on a collection of UNIX® machines. These services are comprised of file transfer and command execution;Z preserves file ownership on...
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This paper generalizes group communications into nested groups for the internet environment. By using a name graph model, two problems in nested group name resolution are identified - resolution loops and resolution d...
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CPS expresses event-driven, parallel simulation programs. Rather than being a programming language, CPS is a structure imposed on an existing language, C++. CPS programs contain sufficient information to be implemente...
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CPS expresses event-driven, parallel simulation programs. Rather than being a programming language, CPS is a structure imposed on an existing language, C++. CPS programs contain sufficient information to be implemented as Bryant-Chandy-Misra, time-warp, or sequential simulations. CPS is independent of any problem domain. We describe the main concepts of CPS, illustrating them using the problem of logic circuit simulation. We identify what information a parallel simulation must contain that is not required for sequential simulation.
The authors' premise is that applications have the ability to tolerate certain types of failures under certain situations. This may, in turn, relax the top-level constraint on failure recovery algorithms in the in...
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The authors' premise is that applications have the ability to tolerate certain types of failures under certain situations. This may, in turn, relax the top-level constraint on failure recovery algorithms in the interprocess communication (IPC) layer and allow exploitation of the inherent tolerance of applications to failures in a systematic way to simplify failure recovery. Using this application-driven approach, the authors present a model of a distributed program based on the well-known client-server relationship among the processes of the program. The model reflects certain generic properties of the application layer that can be exploited by the IPC layer during failure recovery. New techniques as to how the properties can be used for recovery are outlined. The authors use remote procedure call and shared variable as communication abstractions for the client and the server processes in the program to communicate with one another. The simplicity and generality of the failure recovery renders the application-driven approach particularly useful in contemporary distributedsystems which are large and heterogeneous and hence have complex failure modes.< >
This paper describes a modularized AI system being built to help improve electromagnetic compatibility (EMC) among shipboard topside equipment and their associated systems. CLEER is intended to act as an easy to use i...
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This paper describes a modularized AI system being built to help improve electromagnetic compatibility (EMC) among shipboard topside equipment and their associated systems. CLEER is intended to act as an easy to use integrator of existing expert knowledge and pre-existing data bases and large scale analytical models. Due to these interfaces; to the need for portability of the software; and to artificial intelligence related design requirements (such as the need for spatial reasoning, expert data base management, model base management, track-based reasoning, and analogical (similar ship) reasoning) it was realized that traditional expert system shells would be inappropriate, although relatively off-the-shelf AI technology could be incorporated. In the same vein, the rapid prototyping approach to expert system design and knowledge engineering was not pursued in favor of a rigorous systems engineering methodology. The critical design decisions affecting CLEER's development are summarized in this paper along with lessons learned to date all in terms of “how,” “why,” and “when” specific features are being developed.
The Object Library for Parallel Simulation (OLPS) is a set of C++ objects from which a parallel, discrete event simulation or simulation language can be built and run on multiprocessor workstations. OLPS provides a co...
ISBN:
(纸本)9780911801422
The Object Library for Parallel Simulation (OLPS) is a set of C++ objects from which a parallel, discrete event simulation or simulation language can be built and run on multiprocessor workstations. OLPS provides a common interface to the simulation programmer for several parallel simulation algorithms, including implementations of the Chandy-Misra and Time-Warp algorithms. OLPS also provides instrumentation to compare the performance of each parallel algorithm on the same simulation problem. The system currently runs on the V distributed system on the DEC Firefly.
The Object Library for Parallel Simulation (OLPS) is a set of C++ objects from which a parallel, discrete event simulation or simulation language can be built and run on multiprocessor workstations. OLPS provides a co...
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The Object Library for Parallel Simulation (OLPS) is a set of C++ objects from which a parallel, discrete event simulation or simulation language can be built and run on multiprocessor workstations. OLPS provides a common interface to the simulation programmer for several parallel simulation algorithms, including implementations of the Chandy-Misra and Time-Warp algorithms. OLPS also provides instrumentation to compare the performance of each parallel algorithm on the same simulation problem. The system currently runs on the V distributed system on the DEC Firefly.
A recent paper by Meyer compared the usefulness of Genericity and Inheritance as a basis fur static type checking in object oriented systems. Conformance is also being considered by some researchers, and Meyer’s pape...
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