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Buffer and Switch： Road-to-Road Routing Scheme for Intermittently Connected Vehicular Networks

China Communications 2012年第6期9卷 55-70页

作者： Song Chao Liu Ming Wen Yonggang Cao Jiannong Chen Guihai School of Computer Science and Engineering University of Electronic Science and Technology of China Chengdu 611731 P. R. China School of Computer Engineering Nanyang Technological University Singapore Internet and Mobile Computing Laboratory Department of Computing Hong Kong Polytechnic University Hong Kong P. R. China School of Computer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 P. R. China

Due to the road-constrained data delivery and highly dynamic topology of vehicle nodes in a Vehicular Ad Hoc Network (VANET), it is better to construct routing based on the road-to-road pattern than the traditional node-to-node routing pattern in MANETs. However, the challenging issue is the opportunistic forwarding at intersections. Therefore, we propose a novel routing scheme, called Buffer and Switch (BAS). In BAS, each road buffers the data packets with multiple duplicates propagation in order to provide more opportunities for packet switching at intersections. Different from conventional protocols in VANETs, the propagation of duplicates in BAS is bidirectional along the routing path. Moreover, BAS's cost is much lower than other flooding-based protocols due to its spatio-temporally controlled duplicates propagation. Different from recent researches, BAS can deliver packets not only to a stationary node, but also to the stationary or mobile nodes in a specified area. We conduct the extensive simulations to evaluate the performance of BAS based on the road map of a real city collected from Google Earth. The simulation results show that BAS can outperform the existing protocols, especially when the network resources are limited.

关键词： vanet routing manet

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Research on the motion estimation algorithm in video coding

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Information technology Journal 2012年第11期11卷 1660-1663页

作者： Fei, Quan Wei, Wei Shanxi Polytechnic Institute Xianyang 712000 China School of Computer Science and Engineering Xi' An University of Technology Xian 710048 China

This study proposed two algorithms, an adaptive motion estimation algorithm based on Bayesian decision and an improved Motion Vector FieId Adaptive Search Technique (MVFAST) algorithm. The first algorithm proposed in this paper, firstly, statistic the current frame and the before frame coded macro block information, Then, using the Bayesian theory, combined with the consistency characteristics of macro block MV space, to get an accurate and fast prediction motion vector. The second algorithm proposed in this paper with better early termination strategy, that is to set up a dynamic threshoId of the threshoId and take full advantage of the spatial and temporal correlation of video sequences, the use of the adjacent macro block motion vector to block movement by type starting point for prediction using different search strategies on the macro block. © 2012 Asian Network for Scientific Informaction.

关键词： Image coding

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A novel segmentation method for convex lesions based on dynamic programming with local intra-class variance 12

A novel segmentation method for convex lesions based on dyna...

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27th Annual ACM Symposium on Applied Computing, SAC 2012

作者： Yu, Mali Huang, Qiliang Jin, Renchao Song, Enmin Liu, Hong Hung, Chih-Cheng School of Computer Science Huazhong University of Science and Technology Wuhan China Key Laboratory of Education Ministry for Image Processing and Intelligent Control Wuhan Hubei China Radiology Department Second People's Hospital of Nanning Nanning China School of Computing and Software Engineering Southern Polytechnic State University GA United States

ISBN: (纸本)9781450308571

Lesion segmentation plays an important role in medical image processing and analysis. There exist several successful dynamic programming (DP) based segmentation methods for general images. In those methods, the gradient is used as an important factor in the cost function to attract the contours to the boundaries. Since medical images have their characteristics such as low contrast, blurred edges and high noises, the gradient operator cannot work well enough to achieve a satisfactory performance for boundary detection. We define the local intra-class variance and combine it with the dynamic programming method to replace the traditional gradient operation. Experiments on synthetic and X-ray images are carried out and the results are compared with Canny and fast multilevel fuzzy edge detection (FMFED) algorithms. It is demonstrated that the proposed method performs better on medical images with low contrast, blurred edges and high noises. In addition, 483 regions of interest of mammograms randomly extracted from DDSM of the university of South Florida are used to compare our proposed method with the plane-fitting and dynamic programming method (PFDP), and the normalized cut segmentation method (Ncut). The results demonstrate that our method is more accurate and robust than PFDP and Ncut. © 2012 ACM.

关键词： Dynamic programming

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Collaborative caching in P2P streaming networks

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Huazhong Keji Daxue Xuebao (Ziran Kexue Ban)/Journal of Huazhong university of science and technology (Natural science Edition) 2012年第SUPPL.1期40卷 215-218+224页

作者： Gao, Guoqiang Ma, Xiaopu Xu, Zhiyong School of Media and Communication Wuhan Textile University Wuhan 430073 China School of Computer and Information Technology Nanyang Normal University Nanyang 473061 Henan China Department of Mathematics and Computer Science Suffolk University Boston 02101-02117 United States

To alleviate communication pressure of Internet given by P2P streaming systems, this paper implemented a collaborative caching mechanism in P2P streaming networks. Firstly, some measurement experiments were designed for the existing large-scale P2P streaming systems. It was found that the existing applications improved overall system performance through the deployment of dedicated servers, and the collaboration between peers was relatively poor. Then, a chunk's request frequency was used to calculate its values, and obtain the chunk's requesting distribution factor according to its transmission delay. Finally, the peer replaces its cached chunks based on the chunk value and requesting distribution factor. Our goal is to keep those chunks with high requesting frequency and farther away from the current peer in order to achieve a balanced distribution of cached data to improve collaboration between peers. The simulation results show that proposed method has better performance at cache hits, system load and peer collaboration.

关键词： Peer to peer networks

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Numerical Simulation Study on the Water Inrush of Minor Faults in Coal Seam Floor

Numerical Simulation Study on the Water Inrush of Minor Faul...

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2012 International Conference on Modelling,Identification and Control(建模、辨别与控制国际会议 ICMIC 2012)

作者： Cunhan Huang Li Zhang Institute of Resources and Environment HenanPolytechnic UniversityJiao zuo454000 China College of Computer Science and Technology Henan Polytechnic UniversityJiao zuoChina

Based on mechanical analysis and numerical simulation, the water inrush of minor faults concealed in coal seam floor is *** sliding condition of minor fault is obtained with elasticity model which is caused by the disturbance *** the water inrush models of minor faults are established with RFTA-FLOW2D *** shows that there are three stages in the process of minor fault’s water inrush, including the active stage, expanding stage and fissure transfixion *** the understanding of stress, damage and seepage flow evolution, the transformation of floor rock mass from water-resisting strata to inrush pathways is clearly illuminated and the groundwater inrush pathways are ***, the influence of the density of faults on the damage evolution of groundwater inrush is *** some significantly meaningful guides are provided for the investigation on the mechanism and prevention of minor fault’s water inrush in practice.

关键词： Minor faults Numerical Simulation confined aquifer Seepage Field

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A novel joint scheme for turbo code and multilevel space-time modulation

A novel joint scheme for turbo code and multilevel space-tim...

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International Conference on Systems and Informatics (ICSAI)

作者： Li Zhang Xinghai Yang Hongji Xu Huamei Xin College of Computer Science and Technology Henan Polytechnic University Jiaozuo China School of Information Science and Engineering University of Jinan Jinan China School of Information Science and Engineering Shandong University Jinan China College of Physics and Electronics Shandong Normal University Jinan China

We propose a scheme of utilizing multilevel space-time signal-based turbo code (MST-SB-TC) for wireless communication systems with multiple antennas over very rapidly Rayleigh block fading channels where the fading coefficients changes independently for every transmitted signal. No channel state information (CSI) is available and even unitary space-time signals fail to operate. We give an effective method which applies MST-SB-TC as an alternative to the original multilevel space-time modulation and present an effective multilevel space-time (UST) signal-based BCJR-like maximum a posteriori (MAP) decoding algorithm, which makes full use of the channel characteristics when calculating the branch metrics. With iterative decoding and/or multiple receive antennas, it can further improve the system performance, which helps to give an acceptable bit error rate.

关键词： Turbo codes Fading Decoding Iterative decoding Bit error rate Signal to noise ratio Modulation

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The representation of high-order features based on kernel function

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Journal of Information and Computational science 2012年第12期9卷 3617-3624页

作者： Wu, Weiwen Wang, Zhiyan Jie, Xiaomeng Liang, Peng Xu, Xiaowei School of Computer Science and Engineer South China University of Technology Guangzhou 510006 China School of Computer Science Guangdong Polytechnic Normal University Guangzhou 510665 China College of Information Science and Engineering Ocean University of China Qingdao 266100 China

In order to solve the computational complexity problem brought by high-order local features, the representation of high-order local features based on kernel function is proposed. At First, the feature space is mapped to the geometric invariant space by comparing local features extracted from two images. Then, we generate high-order local features by establish a kernel function. At last, a multi-target image classification experiment has been conducted through combining with the support vector machine. The experimental results demonstrate that our proposed method improve classification accuracy by 10%. © 2012 Binary Information Press.

关键词： Image classification

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The incremental image classification method based on semi-supervised learning

International Journal of Digital Content Technology and its ...

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International Journal of Digital Content technology and its Applications 2012年第19期6卷 305-314页

作者： Wu, Weiwen Wang, Zhiyan Liang, Peng Xu, Xiaowei School of Computer Science and Engineer South China University of Technology Guangzhou 510006 China School of Computer Science GuangDong Polytechnic Normal University Guangzhou 510665 China College of Information Science and Engineering Ocean University of China Qingdao 266100 China

In order to use large numbers of unlabeled images effectively, this paper proposes an image classification method based on semi-supervised learning. The proposed method bridges a large amount of unlabeled images and limited numbers of labeled images by exploiting the common topics. The classification accuracy is improved by using the must-link constraint and cannot-link constraint of labeled images. The experimental results on Caltech-101 demonstrate the feasibility and stability of proposed method. Furthermore, due to the present semi-supervised image classification methods lacking of incremental learning ability, we propose an incremental implementation of our method. Comparing with non-incremental learning model in literature, the incremental learning method can improve the computation efficiency of nearly 90%.

关键词： Image classification

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Efficient heuristics for minimizing reconfiguration overhead on VLSI arrays with faults

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Journal of Computational Information Systems 2012年第16期8卷 6663-6670页

作者： Zhu, Yuanbo Wu, Jigang Jiang, Guiyuan Chen, Ke School of Computer Science and Software Engineering Tianjin Polytechnic University Tianjin 300387 China State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100190 China School of Computer Science and Technology Tianjin University Tianjin 300072 China

This paper presents an efficient heuristic algorithm to minimize the overhead on the reconfiguration for two-dimensional VLSI/WSI arrays in the presence of faulty processing elements (PEs). According to the locations of faulty PEs, the proposed technique is utilized to preprocess the host array by identifying some fault-free but unusable PEs as faults, which minimizes the size of the set of fault-free PEs that are actually useful for reconfiguration. Simulation results show that, the improvements over the two existing algorithms are up to 48% and 52% in terms of runtime, respectively. Moreover, the improvement increases with the increasing faulty density of the host arrays. © 2012 Binary Information Press.

关键词： Fault tolerance

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Locality-Sensitive Bloom Filter for Approximate Membership Query

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IEEE Transactions on computers 2012年第6期61卷 817-830页

作者： Yu Hua Bin Xiao Bharadwaj Veeravalli Dan Feng School of Computer Science and Technology Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Wuhan China Department of Computing Hong Kong Polytechnic University Kowloon Hong Kong China Department of Electrical and Computer Engineering National University of Singapore Singapore

In many network applications, Bloom filters are used to support exact-matching membership query for their randomized space-efficient data structure with a small probability of false answers. In this paper, we extend the standard Bloom filter to Locality-Sensitive Bloom Filter (LSBF) to provide Approximate Membership Query (AMQ) service. We achieve this by replacing uniform and independent hash functions with locality-sensitive hash functions. Such replacement makes the storage in LSBF to be locality sensitive. Meanwhile, LSBF is space efficient and query responsive by employing the Bloom filter design. In the design of the LSBF structure, we propose a bit vector to reduce False Positives (FP). The bit vector can verify multiple attributes belonging to one member. We also use an active overflowed scheme to significantly decrease False Negatives (FN). Rigorous theoretical analysis (e.g., on FP, FN, and space overhead) shows that the design of LSBF is space compact and can provide accurate response to approximate membership queries. We have implemented LSBF in a real distributed system to perform extensive experiments using real-world traces. Experimental results show that LSBF, compared with a baseline approach and other state-of-the-art work in the literature (SmartStore and LSB-tree), takes less time to respond AMQ and consumes much less storage space.

关键词： Arrays Accuracy Extraterrestrial measurements Geometry Probabilistic logic Euclidean distance

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