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2015 International Conference on Information and communications Technologies, ICT 2015

作者： Lu, Weifeng Gu, Mengmeng Yang, Luxi College of Computer Nanjing University of Posts and Telecommunications Nanjing210023 China School of Information Science and Engineering SouthEast University Nanjing210096 China Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Nanjing Jiangsu210023 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Jiangsu Province Nanjing Jiangsu210023 China

ISBN: (纸本)9781849199940

In this paper, we present a two-hop-relay WCDMA cellular system with queueing capability, where a call can wait in the incoming buffer at the congested Base Transceiver Station (BTS) if no channel is immediately available, so as to reduce the call blocking rate. We develop an analytic model based on Multidimensional Markov chains. Then based on this model, we can obtain the average transmission rate and the queuing delay performance of the system respectively. Finally, through numerical calculation, we analyze the impact of the various parameters on the performance of the two-hop-relay WCDMA cellular system with queueing capability.

关键词： Queueing theory

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Energy efficient subchannel pairing for buffer-aided multi-relay MIMO-OFDM networks

Energy efficient subchannel pairing for buffer-aided multi-r...

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International Conference on wireless communications and Signal Processing (WCSP)

作者： Shuang Yang Yueming Cai Junquan Hu Wendong Yang Lei Wang Weiwei Yang College of Communications Engineering PLA University of Science and Technology Nanjing China Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education

ISBN: (纸本)9781467376884

In this paper, we consider the buffer-aided multi-relay MIMO-OFDM networks and propose a joint space-time-frequency subchannel pairing scheme, in which subchannels of the source to relay links and relay to the destination links are paired in time, frequency, and space domain (TPFPSP) simultaneously. TPFPSP scheme can increase the equivalent channel gains between source and destination. We derive new expressions for the energy efficiency, the system capacity and the outage probability to examine the performance of TPFPSP scheme. Our analytical and numerical results outline that this TPFPSP scheme brings higher capacity, energy efficiency and better outage probability performance to our system. This work reported here provides detailed insights into the design of new subchannel pairing scheme, which achieves full diversity in space, time and frequency domains.

关键词： Relays MIMO Fading OFDM Eigenvalues and eigenfunctions Energy efficiency wireless communication

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Social-aware file-sharing mechanism for device-to-device communications

Social-aware file-sharing mechanism for device-to-device com...

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International Conference on wireless communications and Signal Processing (WCSP)

作者： Lei Wang Lulu Gao Aiqing Zhang Mingkai Chen National Mobile Communications Research Laboratory Southeast University Nanjing China NUPT Key Lab of Broadband Wireless Communication and Sensor Network Technology China

ISBN: (纸本)9781467376884

Device-to-device (D2D) communication technology can significantly improve energy efficiency and offload base station traffic. It has become a new research focus in next generation mobile communications. In this paper, a file-sharing mechanism based on social networks is proposed for the D2D communication system underlaying cellular networks aiming at improving the users' quality of experience (QoE). In the proposed mechanism, all users are divided into several groups according to the documentation requirements. Then the D2D communication links are built within each group by fully considering the social relationships and trust degrees of users. The target files give priority to be shared through the D2D mode. Theoretical analysis and extensive simulation results show clearly that the social relationships can affect the whole wireless networks significantly. Selecting a user with the largest social degree as a central user can greatly reduce the transmission delay, relieve the heavy burden of base stations and then optimize the overall performance of cellular communication systems.

关键词： Base stations Social network services Delays wireless communication Mobile communication Quality of service

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Inclination gradient-based fall detection algorithm for wrist-worn device

Inclination gradient-based fall detection algorithm for wris...

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IEEE International Conference on Consumer Electronics-Taiwan (ICCE-TW)

作者： ShengQian Zhou Jianxin Chen Xinzhi Wang Liang Zhou Baoyu Zhen Jingwu Cui Key Lab of Broadband Wireless Communication and Sensor Network Technology of Ministry of Education Nanjing University of Posts & Telecommunications Nanjing University of Posts and Telecommunications Nanjing CN

ISBN: (纸本)9781479987467

Fall detection is one of the feasible solutions for solving the problem of aging of population. This paper presents an algorithm to detect falling for the elderly with one wrist-worn device. The algorithm has lower computation complexity to determine the fall event according to the inclination gradient. Experimental results show that it performs better than another similar devices with the average sensitivity and specificity of 94.44% and 100%, respectively.

关键词： Accelerometers Senior citizens Sensitivity Performance evaluation Classification algorithms Complexity theory Legged locomotion

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A Context-aware Data Processing Model in power communication networks

A Context-aware Data Processing Model in power communication...

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IEEE International Conference on communications in China Workshops (ICCC)

作者： Yunfei Guo Kun Wang Shidong Liu Jinghong Guo Heng Lu Smart Grid Research Institute State Grid Nanjing china Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing china

ISBN: (纸本)9781467397025

The power communication networks is a relatively complex system with high security, which is performed in a number of ways, such as safety of power generation equipment, security of transmission and distribution lines, as well as data transmission security. The core of power communication networks security is context-aware data processing. With continuously extending in scale of the power communication networks, power communication data process become more complicated. In order to realize automatization of data processing of the power communication networks, this paper proposed a Context-aware Data Processing Model in power communication networks (CDPM). In this three-layer architecture, a Distributed Database Based on Data Categorization (DDB-DC) is designed in storage layer, which is able to choose the most efficient approach to store the context-aware data from the gathering layer according to different context-aware data types. Then, a Real-time Feature Extraction algorithm (RFE) for context-aware systems is presented in the computing layer to process the context-aware data stream. The model is a new data processing method in power communication networks.

关键词： communication networks Data processing Distributed databases Algorithm design and analysis Data models Feature extraction Correlation

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A Lightweight Encoding Mechanism for Encrypted User Notification on Mobile Device in Power Grid System

A Lightweight Encoding Mechanism for Encrypted User Notifica...

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2015 International Conference on Computer Information Systems and Industrial Applications(CISIA2015)

作者： T.Zhang Z.X.Sun Y.C.Jin State Grid Smart Grid Research Institute Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry Education Nanjing University of Post and Telecommunications

ISBN: (纸本)9781510805750

As a large amount of users are now using the short message service(SMS) for communication,the demand for security is growing much stronger than ever *** notification encrypted with traditional encrypt mechanism can be transported via SMS only if the encrypted message is encoded into text *** are still many defects on existing data encoding mechanism in terms of *** paper provides a lightweight encoding mechanism for encrypted short message based on UCS-2 Chinese character set which has a lower data extension rate than commonly used encoding *** for functionality and efficiency proves the new mechanism improves the performance for user notification transmission via SMS on mobile device in power grid system.

关键词： user notification short message service(SMS) text encryption data encoding UCS-2 Chinese character set

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Normal Inverse Gaussian Approximation to Downlink Inter-cell Interference

Normal Inverse Gaussian Approximation to Downlink Inter-cell...

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IEEE International Conference on communications

作者： Xiaojun Yan Jing Xu Yuanping Zhu Yang Yang Guoping Tan Key Laboratory of Wireless Sensor Network & Communication Shanghai Institute of Microsystem and Information Technology (SIMIT) Chinese Academy of Sciences (CAS) Telecommunications Lab Saarland University

ISBN: (纸本)9781467364300

In orthogonal frequency division multiple access (OFDMA)-based cellular networks subject to the distance-dependent path loss and shadow fading (SF), the downlink inter-cell interference (ICI) for a given user equipment (UE) is essentially a sum of several lognormal random variables (RVs). So far, no method of approximating the lognormal sum distribution is explicitly accurate when the component lognormal RVs with different logarithmic means and logarithmic variances are correlated. In this paper, the Normal Inverse Gaussian (NIG) distribution is proposed to approximate the downlink ICI for a given UE with the correlated SF. First, the downlink ICI is modelled as a sum of several correlated lognormal RVs. Then original moments of the lognormal sum in the logarithmic domain are obtained analytically. Finally the estimated parameters of the NIG distribution are computed explicitly by the mean, variance, skewness and kurtosis of the lognormal sum in the logarithmic domain through moment matching. Numerical results verify the accuracy of the NIG approximation when the correlated component lognormal RVs have different logarithmic means and logarithmic variances, and show that the NIG approximation outperforms the MGF-based lognormal approximation in various scenarios.

关键词： Approximation methods Downlink Interference wireless communication Correlation Monte Carlo methods Fading

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Effect of outdated CSI on buffer-aided underlay cognitive relay networks

Effect of outdated CSI on buffer-aided underlay cognitive re...

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International Conference on wireless communications and Signal Processing (WCSP)

作者： Xuanxuan Tang Yueming Cai Wendong Yang Weiwei Yang Tao Zhang Hualiang Chen College of Communications Engineering PLA University of Science and Technology Nanjing China Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Post and Telecommunications) Ministry of Education

ISBN: (纸本)9781467376884

This work studies the impact of outdated channel state information (CSI) on decode-and-forward (DF) buffer-aided underlay cognitive relay networks (CRNs), with the following three key constraints considered: the maximum transmit power of the secondary network (P), the peak interference power at the primary user (I) and the interference power at the secondary network caused by the primary network (P PS ). This makes it much more involved to handle with than existing works. By modeling the transitions of the buffer states with Markov chain theory, a closed-form expression of the outage probability for the system with finite-size buffers is derived, which depicts the impact of outdated CSI on the outage performance of buffer-aided CRNs. In addition, it is also demonstrated that the performance of the secondary network is improved with the increase of the interference threshold that the primary users can tolerate, but decreases with the increase of the transmit power of the primary network, which is useful in the design of buffer-aided CRNs. Monte-Carlo simulations are given to verify the validity of the theoretical analysis.

关键词： Interference Signal to noise ratio Delays Relay networks (telecommunications) Markov processes Fading

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Risk prediction model based on improved AdaBoost method for cloud users

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Open Cybernetics and Systemics Journal 2015年第1期9卷 44-49页

作者： Zhang, Lin Rao, Kaili Wang, Ruchuan Jia, Yishang College of Computer Nanjing University of Posts and Telecommunications Nanjing210003 China Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks NanjingJiangsu Province210003 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nangjing University of Posts and Telecommunications Ministry of Education Jiangsu Province Nangjing210003 China

Considering the problem how to protect the cloud services from being destroyed by cloud users, the riskprediction model based on improved AdaBoost method is proposed. The risk prediction is regarded as two-class classification problem, and the risk of new cloud users could be predicted by the attributes of historical cloud users. In order to improve the result of predicted, AdaBoost method is adopted in this paper. The error rate of the last training is used to adjust the sample distribution of the next training, which can make the next training have stronger ability of identification for the error-classified samples. At the same time the weight of each weak classifier is set. After all, the strong classifier is generated by combined the weak classifiers through voting, which can improve the overall result of classification. Considering the wrongly-predicted cost, AdaBoost method is improved. The method of cost-sensitive is added into the model in order to minimal the misclassified-cost. Experiments show that the cost-sensitive AdaBoost method has better classification result than the traditional ones and it can predict the risk of the new cloud user effectively and protect the security of the cloud services. © Zhang et al.

关键词： Adaptive boosting

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A Multi-dimensional Index Structure Based on Improved VA-file and CAN in the Cloud

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International Journal of Automation and computing 2014年第1期11卷 109-117页

作者： Chun-Ling Cheng Chun-Ju Sun Xiao-Long Xu Deng-Yin Zhang College of Computer Nanjing University of Posts and Telecommunications Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and TelecommunicationsMinistry of Education Jiangsu Province

Currently,the cloud computing systems use simple key-value data processing,which cannot support similarity search efectively due to lack of efcient index structures,and with the increase of dimensionality,the existing tree-like index structures could lead to the problem of"the curse of dimensionality".In this paper,a novel VF-CAN indexing scheme is ***-CAN integrates content addressable network(CAN)based routing protocol and the improved vector approximation fle(VA-fle) *** are two index levels in this scheme:global index and local *** local index VAK-fle is built for the data in each storage ***-fle is thek-means clustering result of VA-fle approximation vectors according to their degree of *** cluster forms a separate local index fle and each fle stores the approximate vectors that are contained in the *** vector of each cluster center is stored in the cluster center information fle of corresponding storage *** the global index,storage nodes are organized into an overlay network CAN,and in order to reduce the cost of calculation,only clustering information of local index is issued to the entire overlay network through the CAN *** experimental results show that VF-CAN reduces the index storage space and improves query performance efectively.

关键词： Cloud computing index similarity search clustering vector approximation fle(VA-fle) content addressable network(CAN)

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