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Effective capacity region of two-user opportunistic spectrum access

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science china(Information sciences) 2011年第9期54卷 1928-1937页

作者： XU YuHua,WANG JinLong & WU QiHui institute of Communications Engineering,pla university of science and {3.,nanjing 210007,china 1. institute of Communications Engineering PLA University of Science and Technology Nanjing 210007 China

The effective capacity region of the two-user opportunistic spectrum access (OsA) system in Rayleigh fading environment is derived in this *** OsA is a contemporary research topic,little attention has been given to the capacity analysis under quality-of-service (Qos) ***,we use the effective capacity,which is a powerful tool to analyze the Qos requirements in wireless communication systems,to study the sustainable packet arrival rate of the secondary users while meeting statistical Qos *** derive the effective capacity region of the two-user OsA system and propose a method to obtain the capacity region *** addition,by combining the finite state channel model and the activity of the primary user,an extended finite state channel model for the two-user OsA system is also proposed.

关键词： cognitive radio opportunistic spectrum access effective capacity

Interactive group decision making procedure based on uncertain multiplicative linguistic preference relations

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Journal of systems Engineering and Electronics 2010年第3期21卷 408-415页

作者： Zeshui Xu1,2,1.College of Economics and Management,southeast university,nanjing 210096,P.R.china 2.{3. of sciences,university of science and technology of the pla,nanjing 210007,P.R.china College of Economics and Management Southeast UniversityNanjing 210096P.R.China institute of sciences University of Science and Technology of the PLANanjing 210007P.R.China

Group decision making problems are investigated with uncertain multiplicative linguistic preference *** unbalanced multiplicative linguistic label set is introduced,which can be used by the experts to express their linguistic preference information over *** uncertain linguistic weighted geometric mean operator is utilized to aggregate all the individual uncertain multiplicative linguistic preference relations into a collective one,and then a simple approach is developed to determine the experts＇ weights by utilizing the consensus degrees among the individual uncertain multiplicative linguistic preference relations and the collective uncertain multiplicative linguistic preference ***,a practical interactive procedure for group decision making is proposed based on uncertain multiplicative linguistic preference relations,in which a possibility degree formula and a complementary matrix are used to rank the given ***,the proposed procedure is applied to solve the group decision making problem of a manufacturing company searching the best global supplier for one of its most critical parts used in assembling process.

关键词： group decision making uncertain multiplicative linguistic preference relations unbalanced multiplicative linguistic label set consensus degree interaction.

A novel multicluster V-MIMO PCR scheme in large-scale Ad Hoc networks

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science china(Information sciences) 2010年第10期53卷 2097-2105页

作者： ZHOU Yao, CAI YueMing & PAN ChengKang Department of Wireless Communication, institute of Communications Engineering, pla university of science and {3., nanjing 210007, china 1. Department of Wireless Communication Institute of Communications Engineering PLA University of Science and Technology Nanjing 210007 China

A multicluster packet collision resolution (PCR) scheme is a kind of recently proposed virtualMIMO techniques. In existing multicluster PCR schemes, a large-scale wireless Ad Hoc network is divided into clusters and the single cluster PCR scheme is applied independently to resolve collisions in each cluster. However, there are still some flaws in existing multicluster PCR schemes. In this paper, by presenting a concise theoretical analysis model and a new CNs algorithm, a novel multicluster PCR scheme is proposed. Analysis and simulation results show that the proposed scheme can obtain high performance gain with low complexity. The proposed scheme is more robust and applicable than existing schemes.

关键词： packet collision resolution virtual-MIMO cooperative communication cooperative nodes selection

Nitrogen isotopic geochemical characteristics of crude oils in several basins of china

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science china Earth sciences 2005年第8期48卷 1211-1219页

作者： CHEN Chuanping1,2, MEI Bowen1 & CAO Yacheng3.1. Jianghan Petroleum university, Jingzhou 43.100, china 2. Huazhong university of science and {3., Wuhan 43.047, china 3. nanjing institute of soil science, Chinese Academy of sciences, nanjing 210008, china 1. Jianghan Petroleum university 434100 Jingzhou China 2. Huazhong university of science and technology 430047 Wuhan China 3. nanjing institute of soil science Chinese Academy of Sciences 210008 Nanjing China

Nitrogen isotopic ratios of crude oils with different physical and chemical properties in several basins of china have been measured and their geochemistry has been studied ele-mentally combined with molecular organic geochemistry methods. The data indicate that δ 15N is in the range of ?6‰-20‰. They vary with the oils in different sedimentary types of basins. The oils forming in the limnic environment have lower δ 15N with the value of about 1‰-5‰ whereas the oils in saline or semi-saline environment have higher δ 15N, with most samples being above 10‰ and some exceeding 17‰. The average nitrogen isotopic ratio of oils from the Ordovician formation in the Tarim Basin is the lowest, with most samples having δ 15N below zero, which reflects possibly the characteristic of the oils originating mainly from the organic matter formed in marine carbonate sedimentary environment. The δ 15N distribution can be altered by fractionation. It increases obviously because of biodegradation and decreases during hydrocarbon migration. However, the effect of nitrogen isotopic fractionation in the short distance migration is uncon-spicuous.

关键词： nitrogen isotope, crude oil, sedimentary environment, isotopic fractionation, china.

Optimal MAC based cooperative spectrum sensing in cognitive radio networks

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science china(Information sciences) 2012年第6期55卷 1388-1396页

作者： CHEN Zhong 1,ZHANG XianDa 1 & YANG LanJuan 2 1 state Key Laboratory of Intelligent technology and systems,Tsinghua National Laboratory for Information science and technology,Department of Automation,Tsinghua university,Beijing 100084,{3. 2 institute of Command Automation,pla university of science and technology,nanjing 210007,{3. 1. state Key Laboratory of Intelligent technology and systems Tsinghua National Laboratory for Information Science and Technology Department of Automation Tsinghua University Beijing 100084 China2. Institute of Command Automation PLA University of Science and Technology Nanjing 210007 China

This paper considers a cognitive radio (CR) system in non-ideal fading wireless channels and pro-poses cooperative spectrum sensing schemes based on coherent multiple access channels (MAC),serving as an alternative way to improve the cooperative spectrum sensing performance and provide space diversity for spec-trum *** statistics are transmitted using a common channel from the secondary users (sUs) to a fusion center (FC) where the global decision is *** optimal scaling factors of the proposed schemes are obtained by maximizing the detection probability under a target false alarm probability and a transmit power *** the proposed optimal MAC scheme has high computational complexity,a sub-optimal solu-tion based on maximization of the deflection coefficient (DC) is also *** results show that the proposed algorithms can significantly improve the spectrum sensing performance and approach the detection baseline.

关键词： cognitive radio (CR) spectrum sensing multiple access channel (MAC) deflection coefficient optimization

Crystal structure and single crystal EPR of (NH_4)_2(15-crown-5)_3.Cu(mnt)_2] and (NH_4)_2(benzo-15-crown-5)_4[Cu(mnt)_2]·0.5H_2O

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science china Chemistry 2007年第5期50卷 607-613页

作者： sUI YunXia1, WEN LiLi2, ZHANG Huan3.& MENG QingJin2 1 Center of Modern Analysis, nanjing university, nanjing 210093.{3. 2 state Key Laboratory of Coordination Chemistry, Coordination Chemistry institute, nanjing university, nanjing 210093.{3. 3.Jiangnan institute of Computing technology, Wuxi 214083.{3. 1. Center of Modern Analysis Nanjing University Nanjing 210093 China 2. state Key Laboratory of Coordination Chemistry Coordination Chemistry Institute Nanjing University Nanjing 210093 China 3. Jiangnan institute of Computing technology Wuxi 214083 China

The X-ray crystal structures of (NH4)2(15-crown-5)3.Cu(mnt)2] (1) and(NH4)2(benzo-15-crown-5)4-[Cu(mnt)2] ident to 0.5H2O (2) were *** single crystals arecomposed of distinct structures of ammonium-crown ether supramolecular cation and [Cu(mnt)2]^(2-)*** triple-decker dication in complex 1 and a sandwich dimmer in complex 2 wereobserved.X-Band EPR studies on the single crystals of both complex 1 and complex 2 have been carriedout at room temperature,which revealed that complex 2 showed a perfect hyperfine structure of Cuwhereas that of complex 1 could not be *** principal values and direction cosines of theprincipal axes of the g and A tensors were computed by a least-squares fitting *** spindensity of Cu(ll) was estimated according to the principal values of the A tensors and compared wellwith the results calculated based on DFT method.

关键词： supramolecular cation, H-bonding interaction, EPR, g and A tensors, DFT

The characteristics of arc beam shaping in hybrid plasma and laser deposition manufacturing

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science china(Technological sciences) 2006年第2期49卷 238-247页

作者： ZHANG Hai’ou1, QIAN Yingping1,3. WANG Guilan1 & ZHENG Qiguang2 1. school of Material science and technology, Huazhong university of science and technology, Wuhan 43.074,{3. 2. institute of Laser technology and Engineering, Huazhong university of science and technology, Wuhan 43.074,{3. 3. Mechanical Engineering College, Hubei university of technology, Wuhan 43.068,{3. 1. school of Material science and technology Huazhong University of Science and Technology Wuhan 430074 China 3. Mechanical Engineering College Hubei University of Technology Wuhan 430068 China 2. institute of Laser technology and Engineering Huazhong University of Science and Technology Wuhan 430074 China

As a new direct metal prototyping technology,the hybrid plasma and laser deposition manufacturing (PLDM) is proposed in this paper. In order to figure out the characteristics of plasma arc beam and mould in the PLDM process of high temperature alloy, the high speed CCD camera is used to obtain the picture around the plasma arc. Afterwards the sketch of picture is clearly obtained. And the effect of laser parameter, such as average power, pulse width, pulse repetition frequency and the angle between laser beam and plasma arc beam on the plasma arc appearance, is studied experimentally. The results show that the modality of plasma arc beam is markedly influenced by laser beam. And the improvements of shape precision and surface state of the layer deposited by PLDM are confirmed.

关键词： plasma hybrid laser, direct deposition, plasma arc beam, molding character, high-temperature alloy.

Two possible mechanisms for vortex self-organization

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science china Earth sciences 2006年第2期49卷 202-211页

作者： LUO Zhexian2, ZHOU Xiuji1 & GAO shouting3.1. Chinese Academy of Meteorological sciences, Beijing 100081, china 2. Department of space Information science, nanjing university of Information science and {3., nanjing 210044, china 3. institute of Atmospheric Physics, Chinese Academy of sciences, Beijing 100029, china 2. Department of Environmental science Nanjing University of Information Science and Technology Nanjing 210044 China 1. Chinese Academy of Meteorological sciences Beijing 100081 China 3. institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The vortex self-organization is investigated in this paper by four groups of numerical experiments within the framework of quasi-geostrophic model, and based on the experimental results two types of possible mechanisms for vortex self-organization are suggested. The meso-scale to-pography may enable separated vortices to merge into a larger scale vortex; and the interaction of meso-γ and meso-β scale systems may make separated vortices to self organize a typhoon-like vor-tex circulation.

关键词： vortex, self-organization, meso-scale topography, interaction of different scales.

Allocation of power generating and shipping of Hanjiang upstream cascade

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Progress in Natural science:Materials International 2005年第8期15卷 733-741页

作者： LIU Junping1* and CHANG Mingqi 2,3.1. school of Civil Engineering and Architecture, Zhejiang university of technology, Hangzhou 3.0014, china 2. {3. of Water Resources & Hydroelectric Engineering, Xi'an university of technology, Xi'an 710048, china 3. shanxi {3. of Water Resources, Taiyuan 03.001, china) school of Civil Engineering and Architecture Zhejiang University of Technology Hangzhou 310014 China institute of Water Resources and Hydroelectric Engineering Xi'an University of Technology Xi'an 710048 China shanxi institute of Water Resources Taiyuan 030001 China

The optimal model and simulating model of the Hanjiang cascade reservoirs operation with one day as its calculating period are established to coordinate the contradictions between power generating and shipping. The optimal model is solved by progressive optimality algorithm method adopting the theory of large system decomposing and coordinating. By analyzing the water allocation results obtained from six schemes, which are two cascades, four cascades and seven cascades joint operation considering shipping or not, the contradiction degree between power generating and shipping is investigated and some joint operation schemes are proposed.

关键词： cascade power generating contradiction shipping optimal operation.