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Effcient Distributed Skyline Queries for Mobile Applications

Journal of Computer Science & technology 2010年第3期25卷 523-536页

作者：肖迎元陈跃国 Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology Tianjin University of Technology Key Laboratory of Computer Vision and System Tianjin University of Technology School of Computing National University of Singapore Key Laboratory of Data Engineering and Knowledge Engineering Renmin University of China

In this paper, we consider skyline queries in a mobile and distributed environment, where data objects are distributed in some sites （database servers） which are interconnected through a high-speed wired network, and queries are issued by mobile units （laptop, cell phone, etc.） which access the data objects of database servers by wireless channels. The inherent properties of mobile computing environment such as mobility, limited wireless bandwidth, frequent disconnection, make skyline queries more complicated. We show how to efficiently perform distributed skyline queries in a mobile environment and propose a skyline query processing approach, called efficient distributed skyline based on mobile computing （EDS-MC）. In EDS-MC, a distributed skyline query is decomposed into five processing phases and each phase is elaborately designed in order to reduce the network communication, network delay and query response time. We conduct extensive experiments in a simulated mobile database system, and the experimental results demonstrate the superiority of EDS-MC over other skyline query processing techniques on mobile computing.

关键词： skyline distributed query processing mobile database system

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Gene selection and cancer classification: A rough sets based approach

Gene selection and cancer classification: A rough sets based...

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Rough Set and Knowledge technology Conference, RSKT 2008

作者： Sun, Lijun Miao, Duoqian Zhang, Hongyun Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai 201804 China Department of Computer Science and Technology Tongji University Shanghai 201804 China

ISBN: (纸本)3642144667

Indentification of informative gene subsets responsible for discerning between available samples of gene expression data is an important task in bioinformatics. Reducts, from rough sets theory, corresponding to a minimal set of essential genes for discerning samples, is an efficient tool for gene selection. Due to the compuational complexty of the existing reduct algoritms, feature ranking is usually used to narrow down gene space as the first step and top ranked genes are selected . In this paper,we define a novel certierion based on the expression level difference btween classes and contribution to classification of the gene for scoring genes and present a algorithm for generating all possible reduct from informative *** algorithm takes the whole attribute sets into account and find short reduct with a significant reduction in computational complexity. An exploration of this approach on benchmark gene expression data sets demonstrates that this approach is successful for selecting high discriminative genes and the classification accuracy is impressive. © 2010 Springer-Verlag.

关键词： Gene expression

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Utilizing adaptive techniques to supress noise in high frequency ground wave radar

Utilizing adaptive techniques to supress noise in high frequ...

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4th Microwave and Radar Week MRW-2010 - 11th International Radar Symposium, IRS 2010

作者： Gui, Renzhou Key Laboratory of Embedded System and Service Computing Ministry of Education College of Electronics and Information Engineering Tongji University Shanghai 200092 China State Key Laboratory of Millimeter Waves China

ISBN: (纸本)9789955690184

Reducing noise disturbances in the frequency segment of high frequency (HF) ground wave radar and restraining the sidelobes of strong targets that interfere with the detection of weak targets are the interesting Topic. A new method based on an adaptive techniques that solves these problems is proposed. By changing the working time of the frequency spectrum monitor (FSM), we have shown not only that radar can run in the frequency segments with lower noise disturbances, but also that the noise data produced by FSM can be exploited effectively. There is no correlation between the noise and the useful echo signal, though the correlation between noises over very short time periods is strong,. Exploiting the phenomena, we can adjust system parameters in real-time by adaptive methods to solve the two problems,namely sidelobe disturbance of strong targets and noise distrubance in the frequency segment.

关键词： Bandpass filters

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Using index in the MapReduce framework

Using index in the MapReduce framework

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12th International Asia Pacific Web Conference, APWeb 2010

作者： An, Mingyuan Wang, Yang Wang, Weiping Key Laboratory of Computer System and Architecture Graduate University of Chinese Academy of Sciences Beijing China Key Laboratory of Computer System and Architecture Chinese Academy of Sciences Institute of Computing Technology Beijing China

ISBN: (纸本)9780769540122

MapReduce is a programming framework introduced by Google for large-scale data processing. It is usually used in a scan-centric fashion where all the data are split into blocks and Maps are generated for each block to scan and process the data in the block, then Reduces merge outputs from all the Maps. When a query intends to process only a subset of the data selected by a predicate, this brute-force method may cause extra I/O overhead spent on irrelevant data, and the overhead for initiating so many Maps may be nontrivial given that the actually interesting data for the query is comparatively small in volume. We propose an approach to integrate the index into the MapReduce execution in which only an appropriate number of Maps are generated, each of which accesses the data using an index. This approach incurs random I/O and remote access to data, so the overall performance depends on both system parameters and the query characteristics. We build a cost model for both this index access execution and the traditional full scan execution. This cost model can be used to choose between the two execution modes before executing a query. Experiments show that the index access execution can greatly outperform full scan execution when the selectivity of the predicate is low, and the cost model predicts the actual execution cost very well so can be used to determine the execution plan for a query. © 2010 IEEE.

关键词： MapReduce

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l-SkyDiv query:Effectively improve the usefulness of skylines

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Science China(Information Sciences) 2010年第9期53卷 1785-1799页

作者： HUANG ZhenHua1,2*,XIANG Yang1 & LIN ZiYu3 1Department of Computer Science and technology,Tongji University,Shanghai 201804,China 2The key laboratory of Embedded system and service computing,Ministry of Education,Tongji University,Shanghai 200092,China 3Department of Computer Science and technology,Peking University,Beijing 100871,China 1. Department of Computer Science and Technology Tongji University Shanghai 201804 China2. The Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai 200092 China3. Department of Computer Science and Technology Peking University Beijing 100871 China

Skyline query processing has recently received a lot of attention in database *** a set of multi-dimensional objects,the skyline query finds the objects that are not dominated by *** the best of our knowledge,the existing researches mainly focus on how to efficiently return the whole skyline ***,as the cardinality and dimensionality of input dataset increase,the number of skylines grows exponentially,and hence this "huge" skyline set is completely useless to *** by the above fact,in this paper,we present a novel type of l-SkyDiv query,which only returns l skylines having maximum diversity,to improve the usefulness of skyline ***,we prove that the l-SkyDiv query belongs to the NP-Hard problem theoretically,and propose three efficient heuristic algorithms whose time complexities are polynomial to fast implement the proposed ***,we present detailed theoretical analyses and extensive experiments,demonstrating that our algorithms are both efficient and effective.

关键词： skyline query diversity heuristic algorithm query optimization performance evaluation

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Petri Net-Based Cycle Time Analysis of Dual-Arm Cluster Tools With Wafer Revisiting and Swapping Strategy

Petri Net-Based Cycle Time Analysis of Dual-Arm Cluster Tool...

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2011 IEEE International Conference on Robotics and Automation(2011年IEEE世界机器人与自动化大会 ICRA 2011)

作者： NaiQi Wu Feng Chu Chengbin Chu MengChu Zhou Department of Industrial Engineering School of Mechatronics EngineeringGuangdong University of Tech Laboratoire d'IBISC FRE CNRS 3190 Université d'Evry Val d'EssonneCE 1455 Courcouronnes 91020 Evry C Laboratoire G(e)nie Industriel Ecole Centrale ParisGrande voie des Vignes92295 CH(A)TENAY-MALABRY The MoE Key Laboratory of Embedded System and Service Computing Tongji UniversityShanghai 200092Ch

There are wafer fabrication processes in cluster tools that require revisiting. It is shown that swapping is efficient in operating a dual-arm cluster tool. For dual-arm cluster tools with wafer revisiting, if a swap strategy is applied, it forms a three wafer periodical process with three wafers completed in each period. Such a period contains three cycles in a revisiting process and another three cycles in non-revisiting process. Hence, analysis and scheduling of dual-arm cluster tools with wafer revisiting become very complicated. In this work, a Petri net model is developed to describe the operations of such tools. Based on it, it is found that if a swap strategy is applied to a dual-arm cluster tool with wafer revisiting, it is always in a transient state. A systematic method is presented to analyze its performance.

关键词： Robots Semiconductor device modeling Firing Color Fires Load modeling Transient analysis

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A clustering algorithm use SOM and K-Means in Intrusion Detection

A clustering algorithm use SOM and K-Means in Intrusion Dete...

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International Conference on E-Business and E-Government (ICEE)

作者： Wang, Huai-Bin Yang, Hong-Liang Xu, Zhi-Jian Yuan, Zheng Tianjin Key Lab. of Intelligent Computing and Novel Software Technology Tianjin University of Technology 300191 Tianjin China Key Laboratory of Computer Vision and System Ministry of Education 300191 Tianjin China Key Laboratory of Computer Vision and System Ministry of Education China

ISBN: (纸本)9780769539973

Improving detection definition is a pivotal problem for intrusion detection. Many intelligent algorithms were used to improve the detection rate and reduce the false rate. Traditional SOM cannot provide the precise clustering results to us, while traditional K-Means depends on the initial value serious and it is difficult to find the center of cluster easily. Therefore, in this paper we introduce a new algorithm, first, we use SOM gained roughly clusters and center of clusters, then, using K-Means refine the clustering in the SOM stage. At last of this paper we take KDD CUP-99 dataset to test the performance of the new algorithm. The new algorithm overcomes the defects of traditional algorithms effectively. Experimental results show that the new algorithm has a good stability of efficiency and clustering accuracy. © 2010 IEEE.

关键词： Self organizing maps

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License plate locating algorithm based on multi-feature in color image

License plate locating algorithm based on multi-feature in c...

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2010 International Conference on Educational and Information technology, ICEIT 2010

作者： Sun, Jing Xue, Yan-Bing Key Laboratory of Computer Vision and System Ministry of Education Tianjin University of Technology Tianjin 300191 China Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology Tianjin University of Technology 300191 Tianjin China

ISBN: (纸本)9781424480340

A new method for license plate locating based on multi-feature is introduced in this paper. The method proposed can overcome the shortcoming of early methods based on single feature. At first, the algorithm employs HSV color space to get rid of non-license plate area. Then concomitant color feature, statistical letter frequency and geometry feature are used to detect the possible regions. The algorithm is neither confined to the size and position of the plate, nor limited to the complicated background or illumination condition of the image. Experiments show that the method is effective. © 2010 IEEE.

关键词： Color

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A smooth handoff algorithm with dynamic scan time interval

A smooth handoff algorithm with dynamic scan time interval

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International Conference on Electrical and Control Engineering, ICECE 2010

作者： Wang, Huai-Bin Luo, Hong-Wei Wang, Chun-Dong Zhao, Yan-Jun Key Laboratory of Computer Vision and System Ministry of Education Tianjin University of Technology 300191 Tianjin China Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology Tianjin University of Technology 300191 Tianjin China

ISBN: (纸本)9780769540313

Because of the virtue mobility, flexibility, and convenience, more and more wireless network are used in our everyday life. During the move between two scales of different AP (Access Point), the quality of the services heavily depends on the seamless handoff scheme which provide less packet lost. There are many people propose lots of strategies to reduce packet lost and do many contribution to it. In this paper, a dynamically adjusted buffer size algorithm and a predictable handoff tendency formula are used together. We use the two schemes to reduce packet lost. According to analysis the simulation result, we can conclude that the method we used in experiment reduce the packet lost when a MN (Mobile Node) move from one scale to another. © 2010 IEEE.

关键词： Packet loss

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A multi-scale-based super-resolution method for face image

A multi-scale-based super-resolution method for face image

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2010 3rd International Congress on Image and Signal Processing, CISP 2010

作者： Zhang, Simiao Zhang, Hua Zhang, Lan Xue, Yanbing Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology Tianjin University of Technology 300191 Tianjin China Key Laboratory of Computer Vision and System Ministry of Education Tianjin University of Technology 300191 Tianjin China

ISBN: (纸本)9781424465149

We propose a new algorithm about multi-scale-based super-resolution on face image. First, steerable pyramid is used to capture low-level local features in face images, and then these features are combined with pyramid-like parent structure and image patch synthetic approach based on neighborhood to predict the best prior. After that, the prior is integrated into Bayesian maximum a posteriori (MAP) framework. Finally, the optimal high-resolution face image is obtained by a global linear smoothing operator. It is can be seen from the experimental result that oriented facial features in the high-resolution face are recovered well. The most crucial is that our algorithm significantly reduces the computational complexity. ©2010 IEEE.

关键词： Optical resolving power

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