Mobile agents provide a new paradigm for distributed computation. Their unique properties appear well suited to the configuration management of large and complex distributed applications. After outlining our concept o...
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ISBN:
(纸本)0818673958
Mobile agents provide a new paradigm for distributed computation. Their unique properties appear well suited to the configuration management of large and complex distributed applications. After outlining our concept of configuration management, we describe a basic agent infrastructure and its extensions for configuration management of distributed applications. Then we consider aspects of concurrent agents and discuss the advantages of the agent based approach through an example.
Traditional configurable operating systems typically provide a fixed and limited set of functionality. We propose a metalevel architecture, where application-defined objects can choose from a rich selection of possibl...
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ISBN:
(纸本)0818673958
Traditional configurable operating systems typically provide a fixed and limited set of functionality. We propose a metalevel architecture, where application-defined objects can choose from a rich selection of possible configurations and are therefore able to dynamically change the way in which they are executed to the configuration that suits best. This allows applications to adapt operating system behaviour to even unanticipated requirements during run-time. A distributed application which processes multimedia data serves as an example to illustrate the concepts described.
The use of CMOS technology allows the monolithic integration of photosensor arrays together with analog-to-digital (A/D) conversion circuits. The structure of the array can be exploited to increase the connectivity be...
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ISBN:
(纸本)078033650X
The use of CMOS technology allows the monolithic integration of photosensor arrays together with analog-to-digital (A/D) conversion circuits. The structure of the array can be exploited to increase the connectivity between the sensor and the converter, which are in close coupling. Both single-converter per array and multiple-converter per array approaches are therefore possible. This paper presents a comparative study of different A/D conversion architectures incorporated in intelligent optical systems. The presented schemes have been validated by experimental evaluations.
This paper presents a protocol for efficient transaction management in an environment of replicated autonomous databases. Each replicated copy has ownership over mutually exclusive portions of the database. The protoc...
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This paper presents a protocol for efficient transaction management in an environment of replicated autonomous databases. Each replicated copy has ownership over mutually exclusive portions of the database. The protocol improves response time and throughput by exploiting parallelism although reducing the degree of transaction isolation. Most modifications to the database are assumed to be on the locally owned portion of the database, with only occasional nonlocal writes/updates. Read operations, however can access either local or nonlocal objects equally. We are able to prove that users of our parallel replicated database system can view it equivalent to that of a single database providing `degree 2' transaction isolation, i.e. the replication and parallelism is transparent to the application programmer. The protocol communication overheads are limited allowing it to be efficiently implemented over even wide area networks. Experimental results using a prototype demonstrating the performance improvements are presented.
Among test techniques for analog circuits, DC test is one of the simplest methods for BIST application since it is easy to integrate the test pattern generator but also the response analyzer. This paper presents such ...
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ISBN:
(纸本)078033650X
Among test techniques for analog circuits, DC test is one of the simplest methods for BIST application since it is easy to integrate the test pattern generator but also the response analyzer. This paper presents such a technique and focuses on the design and the experimental results obtained with a Built-In Voltage sensor that corresponds in our proposal to the analyzer module. Since this sensor gives directly a logical value, simple or multiple DC observation points can easily guarantee at low cost a maximal fault coverage detection. Experimental results obtained on an integrated chip validate the efficiency and the simplicity of this technique. Finally the sensitivity of this sensor to process variations, temperature and power supply is discussed.
In this paper, a framework for supporting adaptive execution of parallel applications in networks of work-stations is presented. The framework is comprised of two levels of competition. At the first level, the tasks o...
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In this paper, a framework for supporting adaptive execution of parallel applications in networks of work-stations is presented. The framework is comprised of two levels of competition. At the first level, the tasks of each application are partitioned into grains. The grains race one another until all their tasks are finished. The turn-around time of an application can be shortened by sharing the tasks of the heavily loaded grains with the neighboring grains. At the second level, a prototype system called Comedians has been developed, which enables competition among applications for workstations by mechanisms of auction and bidding. The objectives of the Comedians system are to maximize the speedup of individual parallel applications and, at the same time, to allocate workstations efficiently and fairly to the applications. Unlike all related work, this paper suggests an integrated solution to both the issues of adaptive parallelism and parallel application scheduling in a multi-user environment. The experimental results demonstrate the effectiveness of the support for adaptive parallelism and the dynamics of competition among parallel applications.
This paper shows a new hardware solution for implementing barrier synchronization in 2D-mesh multicomputers. The synchronization process is executed in n-1 sequential stages where n is the largest dimension of the nxm...
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This paper shows a new hardware solution for implementing barrier synchronization in 2D-mesh multicomputers. The synchronization process is executed in n-1 sequential stages where n is the largest dimension of the nxm mesh configuration. Each stage establishes simultaneous communication with maximum 4 nodes through additional wired-AND wires, allowing the propagation of information among the adjacent cells every time. This solution presents the following characteristics: a) fast barrier synchronization, b) allows that any subset of nodes participate in each barrier whenever sequential barriers are considered, and c) allows simultaneous execution of multiple barriers whenever subsets of nodes belonging to non-overlapping rectangles are considered. The control logic and number of wired-AND wires are the same per node. Therefore, the system size is easily increased, being only limited by the expansion capacity of the 2D-mesh network. Analytical results indicate that the new approach should perform almost as well as efficient barrier synchronizers.
The Configuration Management Service is the part of system management which provides support for dynamic reconfiguration that allows addition and removal of components without stopping the whole system. This paper pre...
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The Configuration Management Service is the part of system management which provides support for dynamic reconfiguration that allows addition and removal of components without stopping the whole system. This paper presents an efficient algorithm which realizes a difficult compromise between four important criterion: correctness and system consistency, performance and global overhead of the system, support for a large class of applications which will survive system changes, and reducing the required mechanisms for algorithm implementation.
This paper describes an environment for interactive configuration management of software for distributed applications and services. Configuration management involves creating the components which form a distributed sy...
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ISBN:
(纸本)0818673958
This paper describes an environment for interactive configuration management of software for distributed applications and services. Configuration management involves creating the components which form a distributed system;allocating these components to physical nodes and binding the interfaces of the components to each other or to existing services. Components and their required and provided interfaces are represented and accessible in the system-wide domain structure. We describe a graphical configuration environment, based on the Darwin configuration language, which is used to create the required configurations and maintain the configuration structure as part of the overall systems management infrastructure. The paper describes a simple example to show how a system can be initially constructed and subsequently reconfigured at run-time without shutting down the system.
The paper addresses the problem of dynamic configuration management of highly available services. In particular, we are concerned with services that are provided by a group of actively replicated servers and are used ...
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The paper addresses the problem of dynamic configuration management of highly available services. In particular, we are concerned with services that are provided by a group of actively replicated servers and are used by a large, rapidly changing set of clients. In this system model, we propose a Replication Management Protocol to facilitate the dynamic configuration management of the server group, while maintaining service state consistency. We argue about the correctness of the protocol and report on initial implementation results.
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