Component software is a promising approach for dealing with the problem of large scale distributed system development, because it decreases development costs and increases software quality. One of the central issues f...
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ISBN:
(纸本)0769506348
Component software is a promising approach for dealing with the problem of large scale distributed system development, because it decreases development costs and increases software quality. One of the central issues for component software in distributedsystems is the location of components. In large scale distributedsystems trading is already used as a service location mechanism. This is considered the only way to manage services in large scab distributedsystems where complete knowledge of the system is both unreasonable and unrealistic. Providing trading mechanisms appropriate for component development requires a move from appearance based (interface) to behaviour based (semantic) trading. We present a semantically enhanced component trading architecture that enables this move.
Exploratory Visualization is an approach for helping users learn about distributed computations without requiring users to examine source code. Instead visualizations provide intuition about the program's behavior...
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ISBN:
(纸本)0769506348
Exploratory Visualization is an approach for helping users learn about distributed computations without requiring users to examine source code. Instead visualizations provide intuition about the program's behavior and serve as an interface through which the programs are controlled. We have developed an exploratory visualization system with the goals of providing an intuitive and user-friendly user interface and developing an infrastructure that minimizes perturbation. We present a case-study to describe how a naive user can interact with the system to learn about and experiment with the running computation.
This paper describes aspects of a research project in the area of distributed object technology. The main focus of the research is the use of this technology within the domains of Groupware and Multimedia applications...
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ISBN:
(纸本)0769506348
This paper describes aspects of a research project in the area of distributed object technology. The main focus of the research is the use of this technology within the domains of Groupware and Multimedia applications. As part of this research an internet based Virtual Store has been developed as a test-bed for an enhanced object event service. The Virtual Store was designed using UML and uses an enhanced implementation of the CORBA Event Service for communication of state changes within the store and for distribution of multimedia notifications to users of the store.
We are beginning to see distributed dynamic workflow management systems being implemented using CORBA services. However these systems do not use events as the mechanism for co-ordinating workflows. Instead workflow co...
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ISBN:
(纸本)0769506348
We are beginning to see distributed dynamic workflow management systems being implemented using CORBA services. However these systems do not use events as the mechanism for co-ordinating workflows. Instead workflow components use messages to communicate with each other;thereby resulting in tightly coupled systems. We investigate the use of events as the co-ordinating mechanism for implementing dynamic event-based workflow solutions using existing CORBA services. This paper shows the limitations of the CORBA Event Service for dynamic workflow solutions based on a prototype implementation and proposes a more specialised Workflow Event Channel (WEC) that overcomes these limitations. A CORBA implementation of the WEC design enables event based workflow execution environments within a CORBA framework.
Component based programming is a current trend in the development of software. The application is created using components and binding their interfaces appropriately at the configuration level. This is especially inte...
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ISBN:
(纸本)0769506348
Component based programming is a current trend in the development of software. The application is created using components and binding their interfaces appropriately at the configuration level. This is especially interesting for applications that, for availability reasons, claim for dynamic reconfiguration. This paper describes an approach for dynamic reconfiguration of applications based on CORBA components running in an environment called LuaSpace that is composed by the dynamically typed language Lua and a set of tools based on Lua. Components, scripts and glue code are the elements that form an application expressed in Lua. LuaSpace provides support for both programmed and ad-hoc reconfiguration. Although our work focuses at configuration level, LuaSpace also handles components updating.
A methodology for performance debugging of parallel and distributed embedded systems with non-critical end-to-end deadlines is presented. The methodology is based on the measurement of a prototype of the system in exe...
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A methodology for performance debugging of parallel and distributed embedded systems with non-critical end-to-end deadlines is presented. The methodology is based on the measurement of a prototype of the system in execution and is supported by a behavioral model. The main components of the model include the sequences of activities through out the system tasks, which are carried out in response to input events, causing the corresponding output events.
The's paper presents a novel approach to monitoring end-user application activity in a distributed, component-based application. Such monitoring can support the visualisation of user and application activity, syst...
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ISBN:
(纸本)0769506348
The's paper presents a novel approach to monitoring end-user application activity in a distributed, component-based application. Such monitoring can support the visualisation of user and application activity, system auditing, monitoring of system performance, and the provision of feedback. A framework is provided which, by means of reflection, allows the insertion of proxies into a three-tier component-based system. Proxies are inserted dynamically in between the user and the graphical user-interface and between the client application and the rest of the distributed, component-based system. The paper describes: how the monitoring is effected, how information produced by this monitoring can be used to provide a visualisation of application activity, and how this mechanism enables the enhancement and tailoring of feedback throughout the software development life cycle. The viability of this approach is demonstrated by means of a prototype implementation.
Event-based communication is useful in many application domains, ranging from small, centralised applications to large, distributedsystems. Many different event models have been developed to address the requirements ...
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ISBN:
(纸本)0769506348
Event-based communication is useful in many application domains, ranging from small, centralised applications to large, distributedsystems. Many different event models have been developed to address the requirements of different application domains. One such model is the ECO model which was designed to support distributed virtual world applications. Like many other event models, ECO has event filtering capabilities meant to improve scalability by decreasing network traffic in a distributed implementation. Our recent work in event-based systems has included building a fully distributed version of the ECO model, including event filtering capabilities. This paper describes the results of our evaluation of filters as a means of achieving increased scalability in the ECO model. The evaluation is empirical and real data gathered from an actual event-based system is used. The findings show filters to be highly valuable in making distributed implementations of the model scab, that multicast contributes to the scalability and perhaps most significantly, that multicast groups can be dynamically generated from filters using local (per node) rather global knowledge of the distributed application.
The proceedings contain 22 papers. The topics discussed include: Symphony: a Java-based composition and manipulation framework for distributed legacy resources;multithreaded dependence graphs for concurrent Java progr...
ISBN:
(纸本)0769501915
The proceedings contain 22 papers. The topics discussed include: Symphony: a Java-based composition and manipulation framework for distributed legacy resources;multithreaded dependence graphs for concurrent Java programs;state-based reproducible testing for CORBA applications;specifying and analyzing distributed object-oriented systems;channel dependence analysis for slicing Promela;deadlock analysis of synchronous message-passing programs;testing of concurrent programs based on message sequence charts;systematic debugging of parallel programs based on collective breakpoints;automated test sequence generation using sequencing constraints for concurrent programs;specification and modeling of flexible manufacturing systems using behaviors and Petri nets building blocks;evaluation of a methodology for the reverse engineering and parallelization of sequential code;component-based development and verification of safety critical software for a brake-by-wire system with synchronous software components;parallel object server as a data repository for CASE tools;web-based tool support for dynamic management of distribution and parallelism in integrating architecture design and performance evaluation;distributed airport simulation using CORBA and DIS;an architecture for a distributed system for product engineering lifecycle support;data interoperability via surrogate API libraries;and specification and simulation of a concurrent real-time system.
It has long been argued that developing distributedsoftware is a difficult and error-prone activity. Based on previous work on design patterns and skeletons, this paper proposes a template-based approach for the high...
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It has long been argued that developing distributedsoftware is a difficult and error-prone activity. Based on previous work on design patterns and skeletons, this paper proposes a template-based approach for the high-level design and implementation of distributed Virtual Environments (DVEs). It describes a methodology and its associated tool which includes a user-interface, a performance analyser and an automatic code generation facility. It also discusses some preliminary results on a surgical training system.
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