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Distributed GEP query optimization on grid service

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The Journal of china Universities of posts and {2. 2010年第3期17卷 118-122,128页

作者： DENG Yong, WANG Ru-chuan college of Computer, nanjing {2. of posts and telecommunications, nanjing 2.0003, china [a] college of Computer Nanjing University of Posts telecommunications Nanjing 210003 China

In order to better solve the problem of distributed query optimization, a query optimization algorithm on gene expression programming （GEP）（QO-GEP） is presented. On the basis of QO-GEP, distributed GEP query optimization on grid service （DGEPQO-GS） is proposed which combines grid service. Simulated experiments show that with the increment of the number of query relation, query time which QO-GEP carries out query decreases apparently. Meanwhile, with the increase of the number of grid nodes, the average querying success rate of DGEPQO-GS increases significantly.

关键词： gene expression programming distributed query grid service query relation

A NOVEL ALGORITHM OF SUPER-RESOLUtion RECONSTRUCtion FOR COMPRESSED VIDEO

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Journal of Electronics(china) 2007年第3期24卷 363-368页

作者： Xu Zhongqiang Zhu Xiuchang information Industry Ministry and Jiangsu province {2. Lab of image processing ＆ image communication Nanjing University of Posts ＆ Telecommunications Nanjing 210003 China

Super-Resolution (SR) technique means to reconstruct High-Resolution (HR) {2.s from a sequence of Low-Resolution (LR) observations,which has been a great focus for compressed video. Based on the theory of Projection Onto Convex Set (POCS),this paper constructs Quantization Constraint Set (QCS) using the quantization information extracted from the video bit stream. By combining the statistical properties of {2. and the Human Visual System (HVS),a novel Adaptive Quantization Constraint Set (AQCS) is proposed. Simulation results show that AQCS-based SR al-gorithm converges at a fast rate and obtains better performance in both objective and subjective quality,which is applicable for compressed video.

关键词： Super-Resolution (SR) Compressed video Projection Onto Convex Set (POCS) Quantization Constraint Set (QCS)

A novel multi-relay cross-layer cooperative communication strategy based on Jackson queuing model

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Science china(information Sciences) 2010年第4期53卷 842-853页

作者： XU XiaoRong1,2. & ZHENG BaoYu1 1Institute of Signal processing and Transmission, nanjing {2. of posts and telecommunications, nanjing 2.0003, china 2.7} of Telecommunication Engineering, Hangzhou Dianzi {2., Hangzhou 310018, china Institute of Signal processing and Transmission Nanjing University of Posts and Telecommunications Nanjing China college of Telecommunica{2. Engineering Hangzhou Dianzi University Hangzhou China

A novel multi-relay cooperative communication strategy based on Jackson queuing model is pro-posed, which is implemented via a cross-layer design between the physical (PHY) layer and the medium access control (MAC) layer. In the PHY layer, we focus mainly on system outage performance by analyzing in detail the relationship between the SNR threshold and the outage probabilities. While in the MAC layer, system model is treated as a Jackson queuing network, and the queue discipline for each node is assumed to be GI/M/1 model. System throughput and delay performance for the proposed strategy are also illustrated. Simulation results of the proposed cross-layer scheme are presented to validate our theoretical derivations. It is revealed that, the number of cooperative nodes influences system outage performance at high spectral efficiency regimes in the PHY layer while the proposed strategy provides a better throughput and delay performance than conventional schemes in the MAC layer.

关键词： multi-relay cooperative communication cross-layer design Jackson queuing model outage prob- abilities GI/M/1 model system throughput delay performance

A WYNER-ZIV VIDEO CODING METHOD UTILIZING MIXTURE CORRELAtion NOISE MODEL

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Journal of Electronics(china) 2012年第Z2期 197-203页

作者： Hu Xiaofei* ** Zhu Xiuchang* (image processing and image communication key laboratory, nanjing university of posts and telecommunications, nanjing 2.0003, {12.) **(college of Geography and Biological information, nanjing university of posts and telecommunications, nanjing 2.0003, {12.)

In Wyner-Ziv (WZ) Distributed Video Coding (DVC), correlation noise model is often used to describe the error distribution between WZ frame and the side {2.. The accuracy of the model can influence the performance of the video coder directly. A mixture correlation noise model in Discrete Cosine Transform (DCT) domain for WZ video coding is established in this paper. Different correlation noise estimation method is used for direct current and alternating current coefficients. Parameter estimation method based on expectation maximization algorithm is used to estimate the Laplace distribution center of direct current frequency band and Mixture Laplace-Uniform Distribution Model (MLUDM) is established for alternating current coefficients. Experimental results suggest that the proposed mixture correlation noise model can describe the heavy tail and sudden change of the noise accurately at high rate and make significant improvement on the coding efficiency compared with the noise model presented by DIStributed COding for Video sERvices (DISCOVER).

关键词： Transform domain Wyner-Ziv (WZ) DIStributed COding for Video sERvices (DISCOVER) Video coding Correlation noise model Mixture Laplace-Uniform Distribution Model (MLUDM)

Performance evaluation of half-duplex relay-based opportunistic cooperation diversity

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Science china(information Sciences) 2010年第2期53卷 325-334页

作者： ZOU YuLong , ZHENG BaoYu & ZHU Jia Institute of Signal processing and Transmission, nanjing {2. of posts and telecommunications, nanjing 2.0003, china 1. Institute of Signal processing and Transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China

Cooperative diversity is proposed as a means to improve the wireless transmission performance, which can effectively combat the wireless fading through sharing the antennas between source and relay nodes. In this paper, considering the practicability, we investigate the use of half-duplex relay, rather than full-duplex relay, for the opportunistic cooperation diversity. Two combining methods, namely selection diversity combining (SDC) and maximum ratio combining (MRC), are utilized for the implementation of the half-duplex relay-based opportunistic cooperation. Closed-form expressions of outage probability are derived for the proposed oppor- tunistic cooperation as well as the known deterministic cooperation over Rayleigh fading channels. Numerical results show that the opportunistic cooperation is superior to the traditional deterministic cooperation in terms of outage probability and, moreover, the MRC-based case outperforms the SDC-based case no matter which duplex mode relay (i.e., half-duplex and full-duplex) is used for the opportunistic cooperation.

关键词： half-duplex relay cooperative diversity SDC MRC outage probability

A NOVEL CROSS-LAYER STRATEGY OF VIDEO TRANSMISSION TO SOLVE PERFORMANCE ANOMALY IN MULTI-RATE IEEE 802.11 NETWORKS

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Journal of Electronics(china) 2011年第3期28卷 349-358页

作者： Tang Guijin Zhu Xiuchang key Lab of image {2. ＆ communication Nanjing University of Posts and Telecommunications Nanjing 210003 China

When wireless hosts use different rates to transmit data in IEEE 802.11 networks, it will take on the state of performance anomaly which will severely decrease the throughputs of all the higher rate hosts. Hence, it is bad for video service transmission. Considering that video is very sensitive to packet delivery delay but can tolerate some packet losses, we propose a novel cross-layer scheme which takes these two characteristics into consideration. Firstly, the maximum number of retransmissions for a video Medium Access Control (MAC) frame is computed in MAC layer according to video frame rate requirement of application layer and current access delay of MAC layer. Secondly, within the margin of the tolerant Packet Loss Rate (PLR) of application layer, several video MAC frames are allowed to drop so that we can adaptively select the transmission rate as high as possible for the rest of video MAC frames in terms of current channel quality and the maximum number of retransmissions. Experiment results show that the proposed method can reduce the delay and jitter of video service and improve the throughputs of fast hosts. Therefore, it increases the quality of reconstructed video to a certain extent and relieves the performance anomaly of network effectively.

关键词： Multi-rate Video transmission IEEE 802.11 Performance anomaly Cross-layer

Robust cooperative spectrum sensing schemes for fading channels in cognitive radio networks

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Science china(information Sciences) 2011年第2期54卷 348-359页

作者： YUE WenJing1,2. ZHENG BaoYu1,2. MENG QingMin1, CUI JingWu1 & XIE PeiZhong1 1Institute of Signal processing and Transmission, nanjing {2. of posts and telecommunications, nanjing 2.0003, china 2.epartment of Electronic Engineering, Shanghai Jiaotong {2., Shanghai 2.02.0, china 1. Institute of Signal processing and Transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China2. Department of Electronic Engineering Shanghai Jiaotong University Shanghai 200240 China

In cognitive radio systems, cooperative spectrum sensing can detect the presence of the primary user accurately. In practice, however, since the sensing observations are forwarded to a data collector through fading channels, the sensing performance is severely degraded. To deal with this problem, in this paper, we first propose a secondary user selection based cooperative spectrum sensing method to improve sensing performance by decreasing the reporting errors introduced by the fading channels. More specifically, only the secondary users with better signal-to-noise ratio (SNR) for reporting channels are allowed to send their local binary decisions (0 or 1) to the data collector while the others will send nothing. Additionally, we further propose a diversity based cooperative spectrum sensing method which applies existing space-time coding. By exploiting space diversity in CR network, the reporting errors introduced by the fading channel can be decreased and then the sensing performance is improved significantly. For either proposed cooperative spectrum sensing method, the sensing performance is derived and the analytical performance results are given. Our analysis and numerical results verify that proposed methods outperform the conventional cooperative spectrum sensing with OR-rule by taking into account the error effect on the reporting channels.

关键词： cognitive radio (CR) spectrum sensing energy detection diversity technique space-time coding

Optimal power allocation for cognitive relay networks: amplify-and-forward versus selection relay

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Science china(information Sciences) 2011年第4期54卷 861-872页

作者： YUE WenJing 1,2.ZHENG BaoYu 1,2.MENG QingMin 1,YUE WenJie 3 & CUI JingWu 1 1 Institute of Signal processing and Transmission,nanjing {2. of posts and telecommunications,nanjing 2.0003,china 2.Department of Electronic Engineering,Shanghai Jiaotong {2.,Shanghai 2.02.0,china 3 Shanxi Institute of Educational Science,Taiyuan 030009,china 1. Institute of Signal processing and Transmission Nanjing University of Posts and Telecommunications Nanjing 210003 China2. Department of Electronic Engineering Shanghai Jiaotong University Shanghai 200240 China3. Shanxi Institute of Educational Science Taiyuan 030009 China

We consider a cognitive relay network which is defined by a source,a destination,and cognitive relay nodes and primary user *** this network,a source is assisted by cognitive relay nodes which allow coexisting with primary user nodes by imposing severe constraints on the transmission power so that they operate below the noise floor of primary user *** this paper,we mainly study the power allocation strategies of this system to minimize the outage probability subject to total and individual power constraints for cognitive relay nodes and subject to interference constraints for primary user nodes.A relay transmission scheme,namely amplify-and-forward (AF),is *** first present an optimal power allocation (OPA) scheme to minimize the system outage probability,based on instantaneous channel state information among the source,destination and relay nodes and mean channel gains between primary user nodes and cognitive ***,we propose a selection AF scheme (S-AF) where the single best relay is chosen to assist in the transmission and study power allocation strategy for S-AF to minimize outage *** analytical power allocation strategies have been validated through numerical *** results indicate that the AF with OPA and S-AF with OPA have significantly better outage behavior and average throughput than AF and S-AF schemes *** also find that S-AF with OPA achieves a higher throughput,and hence lower outage probability than AF with OPA.

关键词： cognitive radio (CR) relay networks power allocation outage probability

A NOVEL METHOD TO REALIZE COMPRESSED VIDEO SUPER-RESOLUtion RECONSTRUCtion

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Journal of Electronics(china) 2006年第2期23卷 310-313页

作者： Zhou Liang Liu Feng Zhu Xiuchang information Industry Ministry and Jiangsu province {2. Lab of lmage processing and image communication Nanjing University of Posts and Communications Nanjing 210003 China

This letter proposes a novel method of compressed video super-resolution reconstruction based on MAP-POCS (Maximum Posterior Probability-Projection Onto Convex Set). At first assuming the high-resolution model subject to Poisson-Markov distribution, then constructing the projecting convex based on MAP. According to the characteristics of compressed video, two different convexes are constructed based on integrating the inter-frame and intra-frame information in the wavelet-domain. The results of the experiment demonstrate that the new method not only outperforms the traditional algorithms on the aspects of PSNR (Peak Signal-to-Noise Ratio), MSE (Mean Square Error) and reconstruction vision effect, but also has the advantages of rapid convergence and easy extension.

关键词： Super-resolution Compressed video image reconstruction MAP-POCS