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Xiao P.,Hunnan Institute of Engineering | Hu Z.,University of South China
Journal of Software | Year: 2011

As an effective technique for QoS provision, reservation service has been widely applied in various grids. However, plenty of studies have shown that reservation service will bring about many negative effects on system performance, i.e. higher rejection rate and lower resource utilization. To mitigate these negative effects, a relaxed reservation policy is proposed in this paper. It allows grids accepting reservation requests that overlapping with existing ones in two dimensions (temporal and space). In addition, the proposed policy is completely compatible with conventional reservation service, which means it can be applied in all kinds of practical grids. Extensive experiments have been conducted by using real workloads, and the experimental results show that the relaxed reservation policy can achieve higher resource utilization and lower rejection rate comparing to other policies. Also, It shows better adaptiveness when grids are in presence of higher reservation rate. © 2011 ACADEMY PUBLISHER.

Xiao P.,Hunnan Institute of Engineering | Hu Z.,University of South China
Journal of Computers | Year: 2012

To address the issue of reliability evaluation in dynamic grid environment, a workload-aware reliability evaluation model is proposed, in which queuing system is applied to describe the dynamic workload and working of grid resources. Meanwhile, a new type of resource fault, namely Deadline-Miss fault, is introduced to evaluate the reliability of real-time jobs. The validity of the proposed model and its approach to calculate real-time job's reliability are presented theoretically. Extensive experiments are conducted to verify its performance, and the results show that the proposed model can significantly improve the accuracy of reliability evaluation in presence of dynamic workload. Also, scheduling algorithm based on this model can reduce the jobs' mean response time and the deadline-miss rate. © 2012 ACADEMY PUBLISHER.

Xiao P.,Hunnan Institute of Engineering | Hu Z.,University of South China | Qu X.,University of South China
Journal of Software | Year: 2012

To address the issue of resource co-allocation with deadline constraint in grids, a novel approach is proposed to evaluate the deadline-guarantee of co-allocation schemes that obtained from conventional co-allocation policies. Based on this approach, a hybrid-policy coallocation model is also proposed to address the issue of deadline-constrained resource co-allocation in grid environments. The proposed model combines multiple coallocation policies and selects the one with optimal dead line guarantee for scheduling. In this way, the hybrid-policy model combines the merits of different policies, and overcomes the shortcomings of those policies. Extensive simulations are conducted to verify the effectiveness and the performance of the proposed model in terms of dead line miss rate. Experimental results show that it can provide coallocation scheme with improved deadline-guarantee and lower down the deadline-miss rate for real-time applications. © 2012 ACADEMY PUBLISHER.

Jin G.,Hunan University | Jin G.,Northeast Dianli University | Luo A.,Hunan University | Chen Y.,Hunan University | And 2 more authors.
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2016

In order to realize proportional load sharing of parallel inverters in proportion to the inverters volumes under different line impedances, an active power injecting method is presented. After analyzing the key reason about disproportional load sharing of the parallel inverter, this paper analyzes the relationship between the line impedance and the output active power of the inverter, and further presents the proportional load sharing method for parallel inverters. The correction curve of P-V droop coefficient is also provided. The presented method can implement proportional load sharing based on the field line impedances or one time P-V droop coefficient correction during debugging or running process of the inverters. Simulation and experimental results validate the feasibility and superior performance of the presented method. © 2016, The editorial office of Transaction of China Electrotechnical Society. All right reserved.

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