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IEEE International Symposium on Dynamic Spectrum Access Networks

作者： Liu, Quan Pang, Deming Hu, Gang Wang, Xiaodong Zhou, Xingming Natl Univ Def Technol Coll Comp Sci Natl Key Lab Parallel & Distributed Proc Changsha Hunan Peoples R China Natl Univ Def Technol Coll Comp Sci Dept Network Engn Changsha Hunan Peoples R China

ISBN: (纸本)9781467344487;9781467344470

The establishment of common control channel (CCC) is an immense challenge in cognitive radio networks (CRNs). Since the channel number is large and the channel access is opportunistic, the process (a.k.a. rendezvous) that any pair-wise nodes (i.e. rendezvous pair) find a common channel to establish a control channel for communication is hard to achieve, especially in a distributed CRN. Researchers have proposed sequence-based asynchronous channel hopping (ACH) protocols to guarantee rendezvous between transmitting and receiving nodes without requirement of global synchronization. However, these existing protocols emphasize on how to construct the sequences of channel hopping (CH). Even worse, the rendezvous pair in these protocols loyally follow their respective predefined channel hopping sequences before meeting each other (i.e. rendezvous success), which causes rendezvous performance dominated by the sequence structure to be hardly improved further and results in intolerable rendezvous delay due to large channel number and opportunistic access in CRNs. We propose a neighbor cooperation framework by observing sequence diversity in existing ACH protocols, which enables the rendezvous pair to adapt their CH sequences before rendezvous success and improve rendezvous performance with the cooperation of neighboring nodes. Extensive simulation results show that the rendezvous performance of existing ACH protocols can obviously be improved in this framework by cooperation of small number of cooperative neighbors.

关键词： cognitive radio cooperative communication protocols telecommunication channels

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Queueing Analysis of Spectrum Trading for Wireless Cognitive Radio Networks

Queueing Analysis of Spectrum Trading for Wireless Cognitive...

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2nd International Conference on Mechatronics and Intelligent Materials (MIM 2012)

作者： Liu, Lixia Hu, Gang Huang, Zhen Peng, Yuxing Natl Univ Def Technol Coll Comp Natl Key Lab Parallel & Distributed Proc Changsha 410007 Hunan Peoples R China Natl Univ Def Technol Coll Comp Dept Network Engn Changsha 410007 Hunan Peoples R China

ISBN: (纸本)9783037853849

Spectrum trading is an important approach for the secondary users (SU, the unlicensed user) to share the spectrum resource with the primary users (PU, the licensed user). Such economic method can improve not only the efficiency but also the quality of spectrum sharing. For getting the most profit from the spectrum trading, we considered a spectrum trading model based on queueing theory. We analyzed the relationship between the spectrum server and the spectrum demander and discussed the problem of server uncertainty. Simulation results demonstrated the analysis results in terms of the idle probability and average queue size.

关键词： queue cognitive radio network spectrum service primary user

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Study on the effects of ion motion on laser-induced plasma wakes

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PHYSICS OF PLASMAS 2012年第9期19卷 093101-093101-5页

作者： Zhou, Su-Yun Yu, Wei Yuan, Xiao Xu, Han Cao, L. H. Cai, H. B. Zhou, C. T. Soochow Univ Inst Modern Opt Technol Key Lab Adv Opt Mfg Technol Jiangsu Prov Suzhou 215006 Peoples R China Soochow Univ Key Lab Modern Opt Technol Educ Minist China Suzhou 215006 Peoples R China Jiangxi Sci & Technol Normal Univ Sch Mat Sci & Engn Nanchang 330013 Peoples R China Chinese Acad Sci Shanghai Inst Opt & Fine Mech Shanghai 201800 Peoples R China Natl Univ Def Technol Sch Comp Sci Natl Lab Parallel & Distributed Proc Changsha 410073 Hunan Peoples R China Inst Appl Phys & Computat Math Beijing 100088 Peoples R China

A 2D analytical model is presented for the generation of plasma wakes (or bubbles) with an ultra-intense laser pulse by taking into account the response of plasma ions. It is shown that the effect of ion motion becomes significant at the laser intensity exceeding 10(21) W/cm(2) and plasma background density below 10(19) cm(-3). In this regime, ion motion tends to suppress the electrostatic field induced by charge separation and makes the electron acceleration less effective. As a result, the assumption of immobile ions overestimates the efficiency of laser wake-field acceleration of electrons. Based on the analytical model, the dynamics of plasma ions in laser-induced wake field is investigated. It is found that only one bubble appears as the plasmas background density exceeds the resonant density and the deposited laser energy is concentrated into the bubble, resulting in the generation of an ion bunch with extremely high energy density. (C) 2012 American Institute of Physics. [http://***/10.1063/1.4751111]

关键词： plasma accelerators plasma density plasma light propagation plasma transport processes wakefield accelerators wakes

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Favor-Aware distributed Spectrum Allocation via Compressive Skycube Query

Favor-Aware Distributed Spectrum Allocation via Compressive ...

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IEEE Globecom Workshops (GC Wkshps)

作者： Liu, Lixia Hu, Gang Xu, Ming Peng, Yuxing Natl Univ Def Technol Sch Comp Sci Natl Key Lab Parallel & Distributed Proc Changsha 410073 Hunan Peoples R China Natl Univ Def Technol Sch Comp Sci Dept Networks Engn Changsha 410073 Hunan Peoples R China

ISBN: (纸本)9781467349413;9781467349420

In the practical wireless cognitive radio networks (CRNs), the secondary users (SUs) usually show different favors to spectrum attributes, which brings new challenges to spectrum allocation. How to reduce the communication cost and allocate the spectrum according to favors is a meaningful topic. Prior skycube solution, which consists of all possible non-empty skylines, is not suitable for power-limited and resource-scarce CRNs. Aiming at eliminating redundant transmission and allocating spectrum reasonably, we propose a favor-aware distributed spectrum allocation algorithm (FA-DSA) based on compressive skycube query. The main idea is to ignore the information which may not affect the allocation results and only transmit the information which SUs may be interested in. FA-DSA is implemented in three stages: grouping, query and allocation. Grouping is to divide the users into groups according to their different favors, and quering stage is to implement compressive skycube query. After getting the query results, in the allocating stage SUs will make the allocation decision jointly while avoiding conflict with each other. The simulations measure the performance of our approach and show the advantage of FA-DSA in terms of reducing communication cost for query and allocation.

关键词： Skycube query favor spectrum cognitive radio communication cost skyline query

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A Hierarchical Memory Service Mechanism in Server Consolidation Environment

A Hierarchical Memory Service Mechanism in Server Consolidat...

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17th IEEE International Conference on parallel and distributed Systems (ICPADS)

作者： Wang, Liufeng Wang, Huaimin Cai, Lu Chu, Rui Zhang, Pengfei Liu, Lanzheng Natl Univ Def Technol Natl Key Lab Parallel & Distributed Proc Changsha Hunan Peoples R China Univ Xian Sch Econ & Management Xian Peoples R China

ISBN: (纸本)9780769545769

Increasing Internet business and computing footprint motivate server consolidation in data centers. Through virtualization technology, server consolidation can reduce physical hosts and provide scalable services. However, the ineffective memory usage among multiple virtual machines (VMs) becomes the bottleneck in server consolidation environment. Because of inaccurate memory usage estimate and the lack of memory resource managements, there is much service performance degradation in data centers, even though they have occupied a large amount of memory. In order to improve this scenario, we first introduce VM's memory division view and VM's free memory division view. Based on them, we propose a hierarchal memory service mechanism. We have designed and implemented the corresponding memory scheduling algorithm to enhance memory efficiency and achieve service level agreement. The benchmark test results show that our implementation can save 30% physical memory with 1% to 5% performance degradation. Based on Xen virtualization platform and balloon driver technology, our works actually bring dramatic benefits to commercial cloud computing center which is providing more than 2,000 VMs' services to cloud computing users.

关键词： Memory Scheduling Hierarchical Service Server Consolidation Iaas Cloud Computing

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A practical low-latency router architecture with wing channel for on-chip network

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MICROprocESSORS AND MICROSYSTEMS 2011年第2期35卷 98-109页

作者： Lai, Mingche Gao, Lei Ma, Sheng Nong, Xiao Wang, Zhiying Natl Univ Def Technol Dept Comp Natl Key Lab Parallel & Distributed Proc China Changsha Hunan Peoples R China Natl Univ Def Technol Dept Comp Sci Changsha Hunan Peoples R China Natl Univ Def Technol Sch Comp Changsha Hunan Peoples R China

With increasing number of cores, the communication latency of Network-on-Chip becomes a dominant problem due to complex operations per node. In this paper, we try to reduce communication latency by proposing single-cycle router architecture with wing channel, which forwards the incoming packets to free ports immediately with the inspection of switch allocation results. Also, the incoming packets granted with wing channel can fill in the time-slots of crossbar switch and reduce the contentions with subsequent ones, thereby pushing throughput effectively. We design the proposed router using 65 nm CMOS process, and the results show that it supports different routing schemes and outperforms express virtual channel, prediction and Kumar's single-cycle ones in terms of latency and throughput. When compared to the speculative router, it provides 45.7% latency reduction and 14.0% throughput improvement. Moreover, we show that the proposed design incurs a modest area overhead of 8.1% but the power consumption is saved by 7.8% due to less arbitration activities. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.

关键词： On-chip Network Router VLSI design

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Production of high-density high-temperature plasma by collapsing small solid-density plasma shell with two ultra-intense laser pulses

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APPLIED PHYSICS LETTERS 2012年第14期100卷 144101-144101页

作者： Xu, H. Yu, Wei Yu, M. Y. Wong, A. Y. Sheng, Z. M. Murakami, M. Zhang, J. Zhejiang Univ Inst Fus Theory & Simulat Hangzhou 310027 Zhejiang Peoples R China Natl Univ Def Technol Natl Lab Parallel & Distributed Proc Sch Comp Sci Changsha 410073 Hunan Peoples R China China Acad Engn Phys Res Ctr Laser Fus Mianyang 621900 Peoples R China Chinese Acad Sci Shanghai Inst Opt & Fine Mech Shanghai 201800 Peoples R China Ruhr Univ Bochum Inst Theoret Phys 1 D-44780 Bochum Germany Univ Calif Los Angeles Dept Phys Los Angeles CA 90095 USA Shanghai Jiao Tong Univ Key Lab Laser Plasmas Minist Educ Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ Dept Phys Shanghai 200240 Peoples R China Osaka Univ Inst Laser Engn Suita Osaka 5650871 Japan

Three-dimensional particle-in-cell simulations show that the anisotropic collapse of a plasma microshell by impact of two oppositely directed intense laser pulses can create at the center of the shell cavity a submicron-sized plasma of high density and temperature suitable for generating fusion neutrons. (C) 2012 American Institute of Physics. [http://***/10.1063/1.3697983]

关键词： plasma density plasma production by laser plasma simulation plasma temperature

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A Proton Nuclear Magnetic Resonance Metabonomics Approach for Biomarker Discovery in Nonalcoholic Fatty Liver Disease

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JOURNAL OF PROTEOME RESEARCH 2011年第6期10卷 2797-2806页

作者： Li, Hao Wang, Lan Yan, Xianzhong Liu, Qijun Yu, Chaohui Wei, Handong Li, Youming Zhang, Xuemin He, Fuchu Jiang, Ying Beijing Inst Radiat Med Beijing Proteome Res Ctr State Key Lab Prote Beijing 102206 Peoples R China Beijing Univ Chem Technol Coll Life Sci & Technol Beijing Key Lab Bioproc Beijing 100029 Peoples R China Zhejiang Univ Coll Med Affiliated Hosp 1 Digest Dept Hangzhou 310003 Zhejiang Peoples R China Natl Ctr Biomed Anal Beijing 100850 Peoples R China Natl Univ Deference & Technol Natl Lab Parallel & Distributed Proc Changsha 410073 Hunan Peoples R China Fudan Univ Inst Biomed Sci Shanghai 200032 Peoples R China

This study was undertaken to discover novel biomarkers for the noninvasive early diagnosis of nonalcoholic fatty liver disease (NAFLD). A methionine and choline deficient (MCD) diet was used to represent different stages of NAFLD in male C57BL/6 mice. H-1 NMR spectroscopy and principal components analysis (PCA) were used to investigate the time-related biochemical. changes in mice sera induced by the MCD diet. Many serum metabolites' concentrations changed between control and MCD-fed mice. Hierarchical cluster analysis (HCA) and artificial neural networks (ANNs) were used to select the least number of metabolites to be used for the noninvasive diagnosis of various stages of NAFLD;four potential biomarkers, serum glucose, lactate, glutamate/glutamine, and taurine were selected. To verify the diagnostic accuracy of these selected metabolites, their serum concentrations were measured in healthy controls (n = 28), NAFLD patients with steatosis (n = 15), steatosis patients with necro-inflammatory disease (n = 11), and NASH patients (n = 6). On the basis of results from MCD-fed mice model, clinical tests, and previous reports, we propose using the levels of the four metabolites for diagnosing NAFLD at various stages. Furthermore, the probability of developing NAFLD at a particular stage was assessed by multinomial logistic regression (MLR) based on the clinical results of the four serum metabolites.

关键词： nonalcoholic fatty liver disease metabonomics proton nuclear magnetic resonance artificial neural networks serum multinomial logistic regression noninvasive diagnosis biomarkers

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FIT: A Flexible, Lightweight, and Real-Time Scheduling System for Wireless Sensor Platforms

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IEEE TRANSACTIONS ON parallel AND distributed SYSTEMS 2010年第1期21卷 126-138页

作者： Dong, Wei Chen, Chun Liu, Xue Zheng, Kougen Chu, Rui Bu, Jiajun Zhejiang Univ Coll Comp Sci Zhejiang Key Lab Serv Robot Hangzhou 310027 Peoples R China McGill Univ Sch Comp Sci Montreal PQ H3A 2A7 Canada Natl Univ Def Technol Natl Lab Parallel & Distributed Proc Changsha 410073 Hunan Peoples R China

We propose FIT, a flexible, lightweight, and real-time scheduling system for wireless sensor platforms. There are three salient features of FIT. First, its two-tier hierarchical framework supports customizable application-specific scheduling policies, hence, FIT is very flexible. Second, FIT is lightweight in terms of minimizing the thread number to reduce preemptions and memory consumption while at the same time ensuring system schedulability. We propose a novel Minimum Thread Scheduling Policy ( MTSP) exploration algorithm within FIT to achieve this goal. Finally, FIT provides a detailed real-time schedulability analysis method to help check if application's temporal requirements can be met. We implemented FIT on MicaZ motes and carried out extensive evaluations. Results demonstrate that FIT is indeed flexible and lightweight for implementing real-time applications, at the same time, the schedulability analysis provided can predict the real-time behavior. FIT is a promising scheduling system for implementing complex real-time applications in sensor networks.

关键词： Real-time and embedded systems hierarchical design scheduling wireless sensor networks

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Liverbase: A Comprehensive View of Human Liver Biology

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JOURNAL OF PROTEOME RESEARCH 2010年第1期9卷 50-58页

作者： Sun, Aihua Jiang, Ying Wang, Xue Liu, Qijun Zhong, Fan He, Quanyuan Guan, Wei Li, Hao Sun, Yulin Shi, Liang Yu, Hong Yang, Dong Xu, Yang Song, Yanping Tong, Wei Li, Dong Lin, Chengzhao Hao, Yunwei Geng, Chao Yun, Dong Zhang, Xuequn Yuan, Xiaoyan Chen, Ping Zhu, Yunping Li, Yixue Liang, Songping Zhao, Xiaohang Liu, Siqi He, Fuchu Beijing Inst Radiat Med Beijing Proteome Res Ctr State Key Lab Prote Beijing 102206 Peoples R China Natl Univ Deference & Technol Natl Lab Parallel & Distributed Proc Changsha 410073 Hunan Peoples R China Fudan Univ Inst Biomed Sci Shanghai 200032 Peoples R China Fudan Univ Dept Chem Shanghai 200032 Peoples R China Hunan Normal Univ Coll Life Sci Changsha 410081 Hunan Peoples R China Chinese Acad Med Sci Canc Inst & Hosp State Key Lab Mol Oncol Beijing 100021 Peoples R China Peking Union Med Coll Beijing 100021 Peoples R China Chinese Acad Sci Beijing Genom Inst Beijing 101300 Peoples R China Shanghai Ctr Bioinformat Technol Shanghai 200235 Peoples R China

The Liverbase (http://***) integrates information on the human liver proteome, including the function, abundance, and subcellular localization of proteins as well as associated disease information. The overall objective of the Liverbase is to provide a unique public resource for the liver community by providing comprehensive functional annotation of proteins implicated in liver development and disease. The central database features are manually annotated proteins localized in or functionally associated with human liver. In this first version of Liverbase, the associated data includes the human liver proteome (6788 proteins) and transcriptome (11205 significantly expressed genes: 10224 from CHIP and 5422 from MPSS, respecively) from the Chinese human liver proteome project (CNHLPP). As a database made publicly available through the Web site, Liverbase provides browsing and searching capabilities and a compilation of external links to other databases and homepages. Liverbase enables (i) the establishment of liver GO slim with 51 nonredundant items;(ii) systematic searches for proteins within specific functional or metabolic pathways;(iii) systematic searches that aim to find the proteins that underlie common and rare liver diseases;and (iv) the integration of detailed protein annotations derived from the literature. Liverbase also contains an external links page with links to other biological databases and homepages, including GO, KEGG, pfam, SWISS-PROT, and GNF databases. Liverbase users can utilize all these information to conduct systems biology research on liver.

关键词： liver transcriptome proteome quantification localization

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