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Zhu L.,PLA University of Science and Technology | Chen J.,PLA University of Science and Technology | Zhao Y.,PLA University of Science and Technology | Zhao Y.,China Electronic Systems Engineering Corporation
IET Conference Publications | Year: 2010

A novel cross-layer scheduling algorithm with guaranteed QoS is proposed in CRN. A distinct scheduling priority integrating UCSI, QSI and QoS requirements is first proposed for CUs. Base on these scheduling priorities and specific scheduling mechanism, packet scheduling and channel allocation are jointly designed. The simulation results reveal that the proposed algorithm suffers a limited decline in system throughput while reduces the packet delay and packet dropping probability effectively for cognitive users. By the optimized channel assignment with the Channel Allocation Weight, a better performance for spectral utility, packet delay and packet dropping probability is obtained under the dynamic UCSI in CRN. Source

Ren T.,University of Chinese Academy of Sciences | Ren T.,CAS Institute of Computing Technology | Ren T.,China Electronic Systems Engineering Corporation | Fu J.,University of Chinese Academy of Sciences | And 2 more authors.
Gaojishu Tongxin/Chinese High Technology Letters | Year: 2015

In order to improve the performance of a virtual machine's interpreter under the non-uniform memory access (NUMA) architecture, a study of memory access optimization was conducted. Then, a scheme for memory optimization of the interpreters under the NUMA architecture was proposed, and based on it, two novel approaches for an interpreter's memory optimization, namely the one using static instruction dispatching and another using dynamic instruction dispatching, were designed and implemented. According to the scheme, the virtual machine collects the information of the NUMA nodes when it starts up, and automatically generates all the data structures the interpreter needs in each NUMA node; when the interpreter is running on a NUMA node, it uses the two mentioned dispatching optimization approaches to realize its local access to the NUMA nodes. The experimental results demonstrated that the proposed scheme can significantly improve the performance of interpreters in NUMA systems. The results of the experiment using the DaCapo showed that the overall performance of the interpreter was improved by 8%, and the highest increment was up to 23%. The proposed memory optimization algorithm is very easyto implement and can be applied to most NUMA systems. © 2015, Inst. of Scientific and Technical Information of China. All right reserved. Source

Lin Y.,PLA Air Force Aviation University | Liang J.,PLA Air Force Aviation University | Zhao H.,PLA Air Force Aviation University | Wang S.,China Electronic Systems Engineering Corporation | Niu X.,PLA Air Force Aviation University
Yadian Yu Shengguang/Piezoelectrics and Acoustooptics | Year: 2015

A novel UWB antenna yields an impendence bandwidth of 2.0-10.6 GHz is designed in this paper, supposed to fulfill many requirements such as small size, wide working bandwidth, ominidirectional radiation patterns. A novel, feasibility method used for band-notched characteristics is demonstrated and the equivalent circuit for this method is proposed. Simulated and measured results all show that the UWB antenna yields an impendence bandwidth of 2.0-10.6 GHz by defining VSWR 2. Based on this method, a extremely narrow notch band at 5.0-5.90 GHz is realized by adding a patch connected with the radiation patch by a via hole, covering the operating band of WLAN((5.125-5.85 GHz). And it improves the quality of WLAN communication links in UWB environment, realizing spectrum compatibility. © 2015, Sichuan Institute of Piezoelectric and Acoustooptic Technology. All right reserved. Source

Li X.-L.,National University of Defense Technology | Wang H.-M.,National University of Defense Technology | Guo C.-G.,China Electronic Systems Engineering Corporation | Ding B.,National University of Defense Technology | And 3 more authors.
Journal of Zhejiang University: Science C | Year: 2012

Network virtualization is recognized as an effective way to overcome the ossification of the Internet. However, the virtual network mapping problem (VNMP) is a critical challenge, focusing on how to map the virtual networks to the substrate network with efficient utilization of infrastructure resources. The problem can be divided into two phases: node mapping phase and link mapping phase. In the node mapping phase, the existing algorithms usually map those virtual nodes with a complete greedy strategy, without considering the topology among these virtual nodes, resulting in too long substrate paths (with multiple hops). Addressing this problem, we propose a topology awareness mapping algorithm, which considers the topology among these virtual nodes. In the link mapping phase, the new algorithm adopts the κ-shortest path algorithm. Simulation results show that the new algorithm greatly increases the long-term average revenue, the acceptance ratio, and the long-term revenue-to-cost ratio (R/C). © 2012 Zhejiang University and Springer-Verlag Berlin Heidelberg. Source

Qi F.,Beijing University of Posts and Telecommunications | Li Q.,Beijing University of Posts and Telecommunications | Han Q.,Beijing University of Posts and Telecommunications | Du Y.,China Electronic Systems Engineering Corporation | Qiu X.-S.,Beijing University of Posts and Telecommunications
Beijing Youdian Daxue Xuebao/Journal of Beijing University of Posts and Telecommunications | Year: 2014

An improved BP neural network algorithm based on dichotomy was proposed for assessment of electric power communication network risk. The dichotomy was used to adjust the learning rate in the training process. It helps to change the learning rate automatically to the direction of optimization. Simulation shows that the improved algorithm's performance is optimized, such as convergence rate, error accuracy and training time. Source

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