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Channel state division of land satellite mobile and its multi-states Markov model based on fuzzy clustering

Journal of Computational Information Systems 2014年第4期10卷 1349-1356页

作者： Guo, Yecai Yuan, Tao Zhang, Xiuzai College of Electronic and Information Engineering Nanjing University of Information Science and Technology Nanjing 210044 China Jiangsu Key Laboratory of Meteorol Observa and Information Processing Nanjing 210044 China Jiangsu Technology and Engineering Center of Meteorology Sensor Network Nanjing 210044 China

Channel modeling of land mobile satellite (LMS) is the foundation of communication system design and its related circuit design. Furthermore, the research on the channel modeling is the key of satellite communications. Firstly, the propagation characteristics of the land mobile satellite channel (LMSC) are analyzed and their second-order statistical characteristics are derived in this paper. Secondly, the LMSC state division method based on fuzzy clustering analysis is proposed according to the real satellite communication environments. Finally, the multi-states Markov chain model with the real LMS propagation characteristics is established and simulated. Simulation results show that the proposed model can effectively reflect the real propagation characteristics of the LMSC. © 2014 Binary Information Press.

关键词： Fuzzy clustering

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A 0.5 V divider-by-2 design with optimization methods for wireless sensor networks

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Journal of Semiconductors 2013年第5期34卷 115-120页

作者：王利丹李智群 Institute of RF- & OE-ICs Southeast University Engineering Research Center of RF-ICs & RF-Systems Ministry of EducationSoutheast University Jiangsu Provincial Key Laboratory of Sensor Network Technology

A 0.5 V static master-slave D flip-flop （DFF） divider-by-2 is implemented with a 0.13 μm 1P8M RF- mixed signal CMOS process. Low-threshold transistors in a deep-N well with forward-body bias technology are used in the circuit. Each of the D-latch with source coupled logic consists of sensing and latching circuits. To increase the maximum operating frequency and decrease power consumption, the latching current is one half of the sensing current. The circuit optimization methods are described in this paper. The measured maximum operating frequency is 6.5 GHz and the minimum input singled-signal amplitude is 0.15 V.

关键词： low-threshold transistors deep-N well forward-body bias low voltage

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Coverage Enhancement Strategy Based on Novel Perception and Co-evolution for Multimedia sensor networks

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电子学报(英文版) 2013年第1期22卷 135-140页

作者： XIAO Fu WANG Jing SUN Lijuan WANG Ruchuan GUO Jian College of Computer Nanjing University of Posts and Telecommunications Nanjing 210003 China Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Nanjing 210003 China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing 210003 China Provincial Key Laboratory for Computer Information Processing Technology Soochow University Suzhou 215006 China

Coverage enhancement is one of the hot research topics in wireless multimedia sensor net- works. A novel Coverage-enhancing algorithm based on three-dimensional Directional perception and co-evolution (DPCCA) is proposed in multimedia sensor networks on the basis of the model whose pitch angle and deviation angle can be adjusted. Based on the proposed elliptical cone sensing model, we can derive the coverage area of the node and calculate the optimal pitch angle according the information of monitoring area and the nodes, and then the deviation angle is optimized based on co-evolution al- gorithm, which eliminate the overlapped and blind sensing area effectively. A set of simulations demonstrate the ef- fectiveness of our algorithm in coverage ratio.

关键词：无线多媒体传感器网络网络覆盖协同进化感知增强算法网络工程测量模型

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A low power quadrature up-conversion mixer for WSN application

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High technology Letters 2013年第3期19卷 228-232页

作者：吴晨健 Li Zhiqun Institute of RF-& OE-ICs Southeast University Engineering Research Center of RF-ICs & RF-Systems Ministry of EducationSoutheast University Jiangsu Provincial Key Laboratory of Sensor Network Technology

This paper presents an up-conversion mixer for 2.4GHz wireless sensor networks in 0. 181xm RF complementary metal-oxide semiconductor （CMOS） technology. It is based on a double-balanced Gilbert cell type. With two Gilbert cells it was applied quadrature modulation. Operational ampli- tiers are used in this design to improve the conversion gain under low power consumption. The mixer design is based on 0.18txm RF CMOS process. And the mixer test results indicate that under 1.8V power supply, with input frequency 2.4 - 2.4835GHz, the conversion voltage gain is 1.2 - 2dB. When the output frequency is 2.4GHz, its power gain is -4.46dB, and its input referred 1 dB com- pression point is -11.5dBm and it consumes 1.77mA current.

关键词： mixer low power Gilbert operational amplifier

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Energy-efficient node deployment strategy for wireless sensor networks

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The Journal of China Universities of Posts and Telecommunications 2013年第1期20卷 54-57页

作者： SHA Chao WANG Ru-chuan College of Computer Science and Technology Nanjing University of Posts and Telecommunications Jiangsu Provincial Key Laboratory of Wireless Sensor Networks Institute of Computer Technology Nanjing University of Posts and Telecommunications

To balancing energy consumption in wireless sensor networks, we proposed a fixed time interval node broadcasting scheme under variational acceleration straight-line movement model. Simulation results show that the approach proposed in this paper has a superior performance on energy consumption balance compared to uniform broadcasting methods.

关键词： wireless sensor networks energy balance variational acceleration movement

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Interference aware routing for mobile ad hoc networks based on node's sending and receiving capabilities

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The Journal of China Universities of Posts and Telecommunications 2013年第4期20卷 73-79,111页

作者： GU Chao ZHU Qi Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and Telecommunications Key Lab on Wideband Wireless Communications and Sensor Network Technology of Ministry of Education Nanjing University of Posts and Telecommunications

How to efficiently build routes among nodes is increasing important for mobile ad hoc networks （MANETs）. This paper puts forward an interference aware routing protocol called Interference aware cross layer routing protocol （IA-CLR） for MANETs based on the IEEE 802.11 medium access layer （MAC）. By defining the node＇s sending and receiving capabilities, IA-CLR can indicate the interference strength of the link in a real and comprehensive way. Further more, in order to choose the route with minimum bottleneck link interference, a new routing metric is proposed by combining the MAC layer and the network layer for cross layer design. Simulation results show that IA-CLR can significantly improve the performances of network such as the average end-to-end delay, the packets loss ratio and the throughput.

关键词： ad hoc networks routing protocol routing design interference aware

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Impact of MAC frame length on energy efficiency in 6LowPAN

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The Journal of China Universities of Posts and Telecommunications 2013年第4期20卷 67-72页

作者： CHEN Shou-ning YANG Long-xiang ZHAO Yu-juan LI Jing Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Jiangsu Mobile Communication Company Limited Nanjing Branch

To reach necessary end-to-end connectivity between the Internet and wireless sensor networks （WSNs）, the Internet Engineering Task Force （IETF） IPv6 over low power wireless personal area network （6LowPAN） working group has been established and introduced an adaptation layer for integration of IEEE 802.15.4 physical layer/media access control （PHY/MAC） layers and the upper layers of any Intemet protocol （IP）-based networks, such as the Internet. The energy efficiency is one of the most important performance measures in WSNs because most sensor nodes are only battery powered so we should reduce the energy consumption to the lowest to extend the life of nodes. Therefore the determination of MAC frame length should be carefully considered since that the radio frequency （RF） module consumes most the energy of a sensor node meanwhile the MAC protocol is the direct controller of RF module. In this paper, we provide a star-shaped 6LowPAN non-beacon mode with unslotted carrier sense multiple access with collision avoidance （CSMA/CA） mechanism to access to the channel and model the stochastic behavior of a target end node as the M/G/1 queuing system. Analytical expressions for some parameters such as channel busy probability, packet loss probability and energy efficiency are obtained in this paper and our analytical results can clearly show the impact of MAC frame length on the energy efficiency of a target node in both ideal and lossy channel.

关键词： 6LowPAN IEEE 802.15.4 unslotted CSMA/CA M/G/1 queuing system MAC frame length energy efficiency

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Compact and Tunable Mid-IR Light Source Based on a Dual-Wavelength Fiber Laser

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Chinese Physics Letters 2013年第11期30卷 106-108页

作者： CHANG Jian-Hua WANG Ting-Ting ZHANG Chuang GE Yi-Xian TAO Zai-Hong Jiangsu Key Laboratory of Meteorological Observation and Information Processing Nanjing University of Information Science&TechnologyNanjing 210044 Jiangsu Technology&Engineering Center of Meteorological Sensor Network Nanjing University of Information Science&TechnologyNanjing 210044

A compact,tunable mid-IR difference-frequency generation(DFG)light source based on a dual-wavelength fiber laser and a 5mol%MgO-doped periodically poled lithium niobate(MgO:PPLN)crystal is developed and *** output power of 233μW is achieved with a conversion efficiency of 0.1%/*** mid-IR wavelength can be tuned between 3308 nm and 3314 nm by changing the temperature of a pair of fiber Bragg grating(FBG)taking as cavity mirrors in the dual-wavelength fiber laser from 26.5°C to 106.5°C.

关键词： fiber tunable Dual

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Detecting genuine communities from large-scale social networks: A pattern-based method

Detecting genuine communities from large-scale social networ...

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作者： Wu, Zhiang Cao, Jie Wu, Junjie Wang, Youquan Liu, Chunyang Jiangsu Provincial Key Laboratory of E-Business Nanjing University of Finance and Economics Nanjing210003 China College of Computer Science and Engineering Nanjing University of Science and Technology Nanjing210094 China Department of Information Systems School of Economics and Management Beihang 100191 China National Computer Network Emergency Response Technical Team Coordination Center of China Beijing China

Community detection is a long-standing yet very difficult task in social network analysis. It becomes more challenging as many online social networking sites are evolving into super-large scales. Numerous methods have been proposed for community detection from massive networks, but how to reconcile the partitioning efficiency and the community quality remains an open problem. In this paper, we attempt to address this challenge by introducing a COSine-pattern-based COMmunity extraction framework: COSCOM. The COSCOM adopts an extracting view of community detection. It first extracts the so-called asymptotically equivalent structures (AESs) from networks, from which the nodes are further partitioned into crisp communities using any of the existing methods. Specifically, we prove that an AES is a very tight group of nodes, and is actually a cosine pattern defined by the extended cosine similarity. A novel cosine-pattern mining algorithm based on the ordered anti-monotone of cosine similarity is thus proposed for the efficient extraction of AESs. Experiments on various real-world social networks demonstrate the advantage of the extracting view of community detection. In particular, COSCOM shows merits in detecting genuine communities by either internal or external validity. © The British Computer Society 2013. All rights reserved.

关键词： Extraction

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Satellite channel markov model of ka-band based on principal component

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Journal of networks 2014年第7期9卷 1701-1706页

作者： Guo, Yecai Yuan, Tao Xiuzai, Zhang College of Electronic and Information Engineering Nanjing University of Information Science and Technology Nanjing China Nanjing Uni of Info Sci and Tech Jiangsu Key Laboratory of Meteorol Observation and Info Processing Nanjing China Nanjing Uni of Info Sci and Tech Jiangsu Tec and Eng Center of Meteorology Sensor Network Nanjing China

With the consideration of the existing Ka-band satellite channel model in data processing method deficiency, the Ka-band satellite channel propagation characteristic is analyzed and the influence of meteorological factors on the satellite channel is discussed. The channel of meteorological factor principal component is obtained by using the principal component analysis and fuzzy clustering analysis method is introduced into channel classification. The Ka-band satellite channel multi-sates Markov model is established and simulated finally. By comparing the level crossing rate and average fade duration with the former. The results shown that this proposed channel model is more accurate and effective and it is significant to the Ka-band satellite communication research. © 2014 ACADEMY PUBLISHER.

关键词： Principal component analysis

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