Modern society is heavily dependent on wireless networks for providing voice and data communications. Wireless data broadcast has recently emerged as an attractive way to disseminate dynamic data to a large number of ...
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ISBN:
(纸本)142440505X
Modern society is heavily dependent on wireless networks for providing voice and data communications. Wireless data broadcast has recently emerged as an attractive way to disseminate dynamic data to a large number of clients. In data broadcast systems, the server proactively transmits the information on a downlink channel; the clients access the data by listening to the channel. Wireless data broadcast systems can serve a large number of heterogeneous clients, minimizing power consumption as well as protecting the privacy of the clients' locations. The availability and relatively low cost of antennas resulted in a number of potential threats to the integrity of the wireless infrastructure. In particular, the data broadcast systems are vulnerable to jamming, i.e., the use of active signals to prevent data broadcast. The goal of jammers is to cause disruption, resulting in long waiting times and excessive power consumption. In this paper we investigate efficient schedules for wireless data broadcast that perform well in the presence of a jammer. We show that the waiting time of client can be reduced by adding redundancy to the schedule and establish upper and lower bounds on the achievable minimum waiting time under different requirements on the staleness of the transmitted data
The conjugate residual (CR) algorithm is a Krylov subspace algorithm that can be used to obtain fast solutions for symmetric linear systems with very large and very sparse coefficient matrices. By changing the computa...
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The conjugate residual (CR) algorithm is a Krylov subspace algorithm that can be used to obtain fast solutions for symmetric linear systems with very large and very sparse coefficient matrices. By changing the computation sequence in the CR algorithm, this paper proposes an improved Conjugate Residual (ICR) algorithm. The numerical stability of ICR algorithm is same as CR algorithm, but the synchronization overhead that represents the bottleneck of the parallel performance is effectively reduced by a factor of two. And all inner products of a single iteration step are independent and communication time required for inner product can be over lapped efficiently with computation time of vector updates. From the theoretical and experimental analysis it is found that ICR algorithm is faster than CR algorithm as the number of processors in creases. The experiments performed on a 64-processor cluster indicate that ICR is approximately 30% faster than CR.
Dynamic scheduling algorithms for real-time multiprocessor are important components of real-time systems. In this paper, a new algorithm, named Group-Proper (GP), is presented based on analysis of the shortcomings of ...
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Dynamic scheduling algorithms for real-time multiprocessor are important components of real-time systems. In this paper, a new algorithm, named Group-Proper (GP), is presented based on analysis of the shortcomings of myopic algorithm and thrift algorithm. GP algorithm includes two policies: grouping policy and properly choosing policy (PCP). Grouping policy is aimed to increase the utilization of resources. PCP is aimed to enlarge the utilization of CPU. On the condition of ensuring not missing the deadlines of tasks with smaller heuristic value, grouping policy prior chooses the task accessing resources in the shared mode to extend. If a task needn't access resources or the earliest available times of resources required by it are earlier than that of the CPU, PCP assigns the task to the CPU with the earliest available time. Otherwise, PCP assigns the task to the CPU with the closest available times to that of the resources required by it. Simulation results show that acceptance ratio of GP algorithm is higher than that of myopic and thrift.
In this paper, we present a robot middleware technology named robot software communications architecture (RSCA) for its use in networked home service robots. The RSCA provides a standard operating environment for the ...
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ISBN:
(纸本)9781424400546
In this paper, we present a robot middleware technology named robot software communications architecture (RSCA) for its use in networked home service robots. The RSCA provides a standard operating environment for the robot applications together with a framework that expedites the development of such applications. The operating environment is comprised of a real-time operating system, a communication middleware, and a deployment middleware. Particularly, the deployment middleware supports the reconfiguration of component-based robot applications including installation, creation, start, stop, tear-down, and un-installation. In designing RSCA, we have adopted a middleware called SCA from the software defined radio domain and extend it since the original SCA lacks the real-time guarantees and appropriate event services. We have fully implemented RSCA and performed measurements to quantify its run-time performance. Our implementation clearly shows the viability of RSCA
Data value prediction has been widely accepted as an effective mechanism to break data hazards for high performance processor design. Several works have reported promising performance potential. However, there is hard...
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Current Web services composition proposals, such as BPEL, BPSS, BPMN and WSCI, provide notations for describing the control and message flows in Web service collaborations. However, such proposals remain at the descri...
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The low-cost and availability of network of workstations have made them attractive solution for high performance computing. Striking progress of network technology is enabling high-performance global computing, with t...
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In this paper, we present our Grid-based decision tree architecture, with the intention of applying it to both parallel and sequential algorithms. Also, we show that, based on the scope and model of data mining applie...
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In this paper, a parallel loop self-scheduling scheme for heterogeneous PC cluster systems is proposed. Though the proposed scheme does allow users to choose parameters before the execution initialization phase, there...
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