Integrating autonomous enterprise systems allows the cooperation among applications belonging to distinct systems. As an example, this problem shows up when integrating software services of large departments and organ...
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ISBN:
(纸本)0769510655
Integrating autonomous enterprise systems allows the cooperation among applications belonging to distinct systems. As an example, this problem shows up when integrating software services of large departments and organizations in e-government initiatives. this paper studies, in the context of the Unitary Network of the Italian Public Administration, the problem of increasing the availability of services exported by an autonomous enterprise system towards others. In particular we show how a fault tolerant CORBA system, namely the Interoperable Replication Logic (IRL), can be used to increase such an availability by building a replicated cooperative gateway that wraps enterprise applications.
In order to obtain efficiency, current practice in distributed software systems design often suffers from a lack of abstraction. An object-oriented design technique based on UML notations and a special type of high-le...
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ISBN:
(纸本)0769506348
In order to obtain efficiency, current practice in distributed software systems design often suffers from a lack of abstraction. An object-oriented design technique based on UML notations and a special type of high-level Petri-Nets is used to demonstrate how designs can be kept sufficiently abstract to be platform independent and re-usable but still support design alternatives and their evaluation w.r.t. availability and principle system performance.
this paper proposes an advanced reconfiguration scheme using row-column bypassing and direct replacement for two-dimensional mesh-connected processing-node arrays that makes an array usable for massively parallel comp...
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ISBN:
(纸本)0769509363
this paper proposes an advanced reconfiguration scheme using row-column bypassing and direct replacement for two-dimensional mesh-connected processing-node arrays that makes an array usable for massively parallelcomputing and stand-alone computing in an efficient divided manner. this scheme uses an array providing a switching circuit in every node for row-column bypassing and a simple bypass network with a tree structure allocated to the array by graph-node coloring with a minimum inter-node distance of three for direct replacement. It can reconfigure a subarray with a regular matrix of free nodes usable for parallelcomputing in the array while allowing a small delay in the mesh, connections but maintaining a communication path from every busy node being used as stand-alone computing to the outside of the array. the direct replacement is used for substitution of busy nodes which are not covered by row-column bypassing with free nodes located in the rotas or columns to be bypassed, helping to enlarge the size of the reconfigured subarray. the bypass allocation with a minimum distance of three enables distributed communications and simple routing in the array while attaining a large success probability of the direct replacement. the proposed scheme is advantageous for constructing fault-tolerant massively parallel systems by using personal computers or workstations as processing nodes and Ethernet devices for interconnections.
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.
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 withthe 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 withthe system to learn about and experiment withthe running computation.
Component software is a promising approach for dealing withthe 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 withthe 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 distributed systems is the location of components. In large scale distributed systems trading is already used as a service location mechanism. this is considered the only way to manage services in large scab distributed systems 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.
In this paper, we describe the design and implementation of a portable run-time system for GOP, a graph-oriented programming framework aiming at providing high-level abstractions for configuring and programming cooper...
ISBN:
(纸本)0769509363
In this paper, we describe the design and implementation of a portable run-time system for GOP, a graph-oriented programming framework aiming at providing high-level abstractions for configuring and programming cooperative parallel processes. the runtime system provides an interface with a library of programming primitives to the low-level facilities required to support graph-oriented communications and synchronization. the implementation is on top of the parallel Virtual Machine (PVM) in a local area network of Sun workstations. Issues related to the implementation of a graph operations in a distributed environment are discussed. Performance of the runtime system is evaluated by estimating the overheads associated with using GOP primitives as opposed to PVM.
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.
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.
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