real-timedistributed collaboration applications are characterized by close co-operation among processes. Concurrency control and timeliness of the response are essential requirements for such applications. As mobile ...
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real-timedistributed collaboration applications are characterized by close co-operation among processes. Concurrency control and timeliness of the response are essential requirements for such applications. As mobile systems are characterized by frequent disconnections and physical mobility from one cell to another providing real-timedistributed collaboration for mobile systems is a real challenge. In this paper, we propose a framework for concurrency control in real-timedistributed collaboration applications for mobile systems. We view mobile systems as a three-tier architecture and propose a data-centric framework for optimistic concurrency control. The framework is built on top of a totally ordered exactly-once multicast protocol. Our model ensures that number of messages on the wired network is independent of the number of mobile hosts in the system. We have implemented and tested our framework by developing a collaborative text editor application over exactly-once multicast protocol.
There is a wide spread usage of hardware design languages (HDL) to speed up the time to market for the design of modern digital systems. Verification engineers can simulate hardware in order to verify its performance ...
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ISBN:
(纸本)9780769519708
There is a wide spread usage of hardware design languages (HDL) to speed up the time to market for the design of modern digital systems. Verification engineers can simulate hardware in order to verify its performance and correctness with help of an HDL. However, simulation can't keep pace with the growth in size and complexity of circuits and has become a bottleneck of the design process. distributed HDL simulation on a cluster of workstations has the potential to provide a cost effective solution to this problem. We describe the design and implementation of DVS, an object-oriented framework for distributed Verilog simulation. Verilog is an HDL which sees wide industrial use. DVS is an outgrowth of clustered time warp, originally developed for logic simulation. The design of the framework emphasizes simplicity and extensibility and aims to accommodate experiments involving partitioning and dynamic load balancing. Preliminary results obtained by simulating a 16 bit multiplier are presented.
This paper presents an application specific reconfigurable architecture based on coarse-grain FPGA for real-timeparallel particle filters. The architecture consists of a set of heterogeneous arithmetic units and buff...
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This paper presents an application specific reconfigurable architecture based on coarse-grain FPGA for real-timeparallel particle filters. The architecture consists of a set of heterogeneous arithmetic units and buffer banks, where their interconnections are reconfigurable at the hardware level. The proposed architecture separates fixed and reconfigurable units for high-throughput realization. We compare potential throughput of the design with that of commercial FPGAs and DSPs. The proposed architecture is implemented in 0.25 /spl mu/m CMOS process.
Clusters and distributedsystems offer fault tolerance and high performance through load sharing, and are thus attractive in real-time applications. When all computers are up and running, we would like the load to be ...
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Clusters and distributedsystems offer fault tolerance and high performance through load sharing, and are thus attractive in real-time applications. When all computers are up and running, we would like the load to be evenly distributed among the computers. When one or more computers-fail the must be redistributed. The redistribution is determined by the recovery scheme. The recovery scheme should keep the load as evenly distributed as possible even when the most unfavorable combinations of computers break down, i.e. we want to optimize the worst-case behavior. In this paper we define recovery schemes, which are optimal for a number of important cases. We also show that the problem of finding optimal recovery schemes corresponds to the mathematical problem of finding sequences of integers with minimal sum and for which all sums of subsequences are unique.
The proceedings contain 47 papers. The special focus in this conference is on Mathematical Models, Architectures for Computer Network Security, Intrusion Detection and Public Key Distribution. The topics include: A di...
ISBN:
(纸本)3540407979
The proceedings contain 47 papers. The special focus in this conference is on Mathematical Models, Architectures for Computer Network Security, Intrusion Detection and Public Key Distribution. The topics include: A distributed forensics network;implementing a calculus for distributed access control in higher order logic and HOL;complexity problems in the analysis of information systems security;a behavior-based approach to securing email systems;real-time intrusion detection with emphasis on insider attacks;relating process algebras and multiset rewriting for immediate decryption protocols;a knowledge-based repository model for security policies management;symbolic partial model checking for security analysis;rule-based systems security model;enhanced correlation in an intrusion detection process;safeguarding SCADA systems with anomaly detection;experiments with simulation of attacks against computer networks;automatic generation of finite state automata for detecting intrusions using system call sequences;advanced certificate status protocol;efficient group key management with off-line members;a certificate status checking protocol for the authenticated dictionary;context-dependent access control for web-based collaboration environments with role-based approach;a signcryption scheme based on secret sharing technique;a zero-knowledge identification scheme based on an average-case NP-complete problem;achieveability of the key-capacity in a scenario of key sharing by public discussion and in the presence of passive eavesdropper;on cipher design based on switchable controlled operations;encryption and data dependent permutations and detection and removal of hidden data in images embedded with quantization index modulation.
In this paper, we propose a distributed prioritized h-out of-k mutual exclusion algorithm for a mobile ad hoc network (MANET) with real-time or prioritized *** h-out of-k mutual exclusion problem is a generalization o...
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ISBN:
(纸本)0780378407
In this paper, we propose a distributed prioritized h-out of-k mutual exclusion algorithm for a mobile ad hoc network (MANET) with real-time or prioritized *** h-out of-k mutual exclusion problem is a generalization of the k-mutual exclusion problem and the mutual exclusion problem. The proposed algorithm is sensitive to link forming and link breaking and thus is suitable for a MANET. If we do not consider the link breaking and forming, the proposed algorithm can also be applied to distributedsystems consisting of stationary nodes that communicate with each other by exchanging messages over wired links. For non-real-time applications, we may associate the priority with the number of requested resources to achieve the maximum degree of concurrency.
We propose a new resource discovery protocol, realTOR, which is based on a combination of pull-based and push-based resource information dissemination. realTOR has been designed for real-time component-based distribut...
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We propose a new resource discovery protocol, realTOR, which is based on a combination of pull-based and push-based resource information dissemination. realTOR has been designed for real-time component-based distributed applications in very dynamic or adverse environments. realTOR supports survivability and information assurance by allowing the migration of components to safe locations under emergencies like external attack, malfunction, or lack of resources. Simulation studies show that under normal and heavy load conditions realTOR remains very effective in finding available resources with a reasonably low communication overhead. realTOR: 1) effectively locates resources under highly dynamic conditions, 2) has an overhead that is system-size independent, and 3) works well in highly adverse environments. We evaluate the effectiveness of a realTOR implementation as part of Agile Objects, an infrastructure for real-time capable, highly mobile Java components.
The complexity of building and validating software is a growing challenge for developers of distributedreal-time and embedded (DRE) applications. While DRE applications are increasingly based on commercial off-the-sh...
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The complexity of building and validating software is a growing challenge for developers of distributedreal-time and embedded (DRE) applications. While DRE applications are increasingly based on commercial off-the-shelf (COTS) hardware and software elements, substantial time and effort are spent integrating these elements into applications. Integration challenges stem largely from a lack of higher level abstractions for composing complex applications. As a result, considerable application-specific "glue code" must be rewritten for each successive DRE application. This paper makes three contributions to the study of composing reusable middleware from standard components in DRE applications: it (1) describes the limitations of current approaches in middleware composition, (2) discusses the minimum set of requirements required of reusable middleware components, and (3) presents recurring patterns for software composition as applied to CIAO (Component-Integrated ACE ORB), our open-source component model implementation.
Many network events need to be handled in a timely fashion. However, current practices are not sufficient to support timely handling of network events mainly due to the lack of a real-time network management model and...
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ISBN:
(纸本)0769519296
Many network events need to be handled in a timely fashion. However, current practices are not sufficient to support timely handling of network events mainly due to the lack of a real-time network management model and facilities. In this paper, we propose a network management system, named a real-timedistributed network management (RTDNM), in which the telecommunication management network (TMN) model and the time-triggered message-triggered object (TMO) model are incorporated to support network management facilities and timely handling of network events. In order to realize RTDNM, temporal characteristics of managed objects in a network are modeled and CMIS/CMIP, a network management protocol used in TMN, is annotated whit real-time constraints so that timely handling of network events can be supported. A message scheduling scheme for network management is proposed to guarantee timeliness for critical network events. Finally, we present the design of our RTDNM and show current results with a prototype implementation. The scheme presented turned out to be effective for timely handling of network events.
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