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.
作者：
Chen, ZUniv Missouri
Dept Civil & Environm Engn Fac Struct Engn Columbia MO 65211 USA
Based on the failure mechanisms of brittle solids under dynamic loading conditions, a strain-based damage diffusion model is proposed to simulate the evolution of localization due to microcracking. A three-dimensional...
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Based on the failure mechanisms of brittle solids under dynamic loading conditions, a strain-based damage diffusion model is proposed to simulate the evolution of localization due to microcracking. A three-dimensional diffusion equation is formulated with local rate-independent and rate-dependent damage evolution laws, respectively. the diffusion equation governing the evolution of damage is incorporated into the hyperbolic equation governing the wave propagation in a parallel setting. A parametric study is performed to investigate the effects of model parameters on the diffusion of damage. One- and two-dimensional sample problems are considered to illustrate how the dynamic evolution of localization can be simulated without using nonlocal models in the strain-stress space. the relationship between the proposed approach and the existing ones for localization problems is also discussed based on the preliminary results obtained in this paper. It appears that the proposed approach might be an effective numerical procedure to simulate the evolution of localization, withparallelcomputing, in a single computational domain involving different lower-order governing differential equations. (C) 2000 Elsevier Science Ltd. All rights reserved.
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.
the international Workshop on Embedded/distributed HPC Systems and Applications (EHPC) is a forum for the presentation and discussion of approaches, research findings, and experiences in the applications of High Perfo...
ISBN:
(纸本)354067442X
the international Workshop on Embedded/distributed HPC Systems and Applications (EHPC) is a forum for the presentation and discussion of approaches, research findings, and experiences in the applications of High Performance computing (HPC) technology for embedded/distributed systems. Of interest are boththe development of relevant technology (e.g.: hardware, middleware, tools) as well as the embedded HPC applications built using such technology.
Event-based communication is useful in many application domains, ranging from small, centralised applications to large, distributed systems. 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, distributed systems. 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.
Design on the Web raises challenging questions concerning how users interact with objects, applications, and other users. In this work, we propose a collaborative and interactive client-server design framework and imp...
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ISBN:
(纸本)0769509363
Design on the Web raises challenging questions concerning how users interact with objects, applications, and other users. In this work, we propose a collaborative and interactive client-server design framework and implement a room design system for our study. We hare integrated technologies used in distributed computation (Java and CORBA) and computer graphics (VRML). It divides the design process into three tiers. First, collaborative and interactive design, viewing, and publishing. Second, scene generation. third, scene database management. Our system can be applied in Electronic Commerce to improve the existing systems by allowing customers to select furniture and to visualize the whole furnished room in 3-D.
In this paper we consider the problem of routing packaets in two-dimensional torus-connected processor arrays. Motivated by recent theoretical work on dynamic routing, we address the dynamic case where packets are con...
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ISBN:
(纸本)0769509363
In this paper we consider the problem of routing packaets in two-dimensional torus-connected processor arrays. Motivated by recent theoretical work on dynamic routing, we address the dynamic case where packets are continously injected into the network. We describe three greedy hot-potato routinig algorithms and present simulation experiments on tori of several sizes using four well-known greedy ( also known as work -conserving) protocols (namely FIFO, LIFO, FTG, and NTG) for the implementation of injection buffers. Our results demonstrate that there exists a greedy injection queueing protocols for injection rates very close to 100% of the network capacity. Furthermore, according to the algorithms we studied, we can claim that the one-pass property is not appropriate for the dynamic case, since the syestem cannot achieve stability at high injection rates.
the proceedings contain 40 papers. the topics discussed include: parallel real-time computation: sometimes quantity means quality;a parallel tabu search and its hybridization with genetic algorithm;reconfigurable mesh...
ISBN:
(纸本)0769509363
the proceedings contain 40 papers. the topics discussed include: parallel real-time computation: sometimes quantity means quality;a parallel tabu search and its hybridization with genetic algorithm;reconfigurable mesh-connected processor arrays using row-column bypassing and direct replacement;batched circuit switched routing for efficient service of requests;environment of multiprocessor simulator development;portable runtime support for graph-oriented parallel and distributed programming;comprehensive evaluation of an instruction reissue mechanism;an accurate analysis of reliability parameters in meshes with fault-tolerant adaptive routing;on the effect of link failures in fibre channel storage area networks;and an approximation algorithm for multiprocessor scheduling of trees with communication delays.
Efficient communication on fetching remote data is a critical parameter in distributed shared-memory multiprocessors (DSM) in order to achieve high performance. Message-passing techniques are used in many modern commu...
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ISBN:
(纸本)0769509363
Efficient communication on fetching remote data is a critical parameter in distributed shared-memory multiprocessors (DSM) in order to achieve high performance. Message-passing techniques are used in many modern communication systems and routers are essential building blocks for these communication systems. Hence, in this paper emphasis is placed on the design of routers for 2-ary n-cube networks. Based on a simple deadlock free algorithm, we analyze the influence of the router structure. To be more precise, the parameters considered were the clock frequency and the number of pipeline stages of the router. the performance evaluation for DSM applications shows there are significant gains in using segmented routers designs. In our evaluations, results show an improvement of up to 12% in the execution time of some applications. this improvement occurs even though the base latency of the router has increased by 40%.
We investigate T m (Qd), the time required to broadcast m 2 1 messages in a d-dimensional hypercube under the telephone model. We give exact values for Tm(Qd) for m 5 2d-1 andform 2 2d+1. F0r2~-, +1 5 m 5 2d, weproduc...
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