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A New Clustering Algorithm for Categorical Attributes

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 318-322页

作者： Songfeng Lu, Zhengding Lu (College of computer science and technology, Huazhong {3. of science and technology, Wuhan 43.074, china) College of computer science and technology Huazhong University of Science and Technology Wuhan 430074 China

In traditional data clustering, similarity of a cluster of objects is measured by distance between objects. Such measures are not appropriate for categorical data. A new clustering criterion to determine the similarity between points with categorical attributes is pre- sented. Furthermore, a new clustering algorithm for categorical attributes is addressed. A single scan of the dataset yields a good clus- tering, and more additional passes can be used to improve the quality further.

关键词： data mining clustering similarity Information

Secure, dependable and publicly verifiable distributed data storage in unattended wireless sensor networks

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science china(Information sciences) 2010年第5期53卷 964-979页

作者： REN Wei 1 , REN Yi 2 & ZHANG Hui 3.1 School of computer science, china {3. of Geosciences (Wuhan), Wuhan 43.074, china 2 department of Information and Communication technology, {3. of Agder (UiA), Norway 3.department of Electronics, Politecnico di Torino (POLITO), Italy 1. School of computer science China University of Geosciences (Wuhan) Wuhan 430074 China2. Department of Information and Communication Technology University of Agder (UiA) Kristiansand Norway3. Department of Electronics Politecnico di Torino (POLITO) Torino Italy

In unattended wireless sensor networks (UWSNs), sensed data are stored locally or at designated nodes and further accessed by authorized collectors on demand. This paradigm is motivated by certain scenarios where historical or digest data (e.g., average temperature in a day), instead of real-time data, are of interest. The data are not instantly forwarded to a central sink upon sensing, thereby saving communication energy for transmission. Such a paradigm can also improve data survivability by making use of distributed data storage in cheap flash memory on nodes. However, the security and dependability of such data storage are critical for the future data accessibility in UWSNs. To address this issue, we propose a secure and dependable distributed storage scheme for UWSNs. Our scheme takes advantages of both secret sharing and Reed-Solomon code, which can achieve computational security and maintain low communication overhead in terms of shortened data dispersing size. We also propose a general coding method to publicly verify data integrity in a distributed manner, with low communication and storage overhead, and without the need of holding original data. The extensive analysis justifies that our scheme can provide secure, dependable and publicly verifiable distributed data storage in UWSNs even in the presence of node compromise and Byzantine failure.

关键词： secure storage dependability data integrity wireless sensor networks wireless network security

Biogas recovery from microwave heated sludge by anaerobic digestion

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science china(Technological sciences) 2010年第1期53卷 144-149页

作者： QIAO Wei1,WANG Wei2,ZHU CuiPing3.& ZHANG ZhongZhi1 1 College of Chemical science and Engineering,china university of Petroleum,Beijing 102249,china 2 department of Environmental science and Engineering,tsinghua university,Beijing 10084,china 3.J & K china Cleaning Energy technology Co.Ltd.,Beijing 100085,china 1. College of Chemical science and Engineering China University of Petroleum Beijing 102249 China2. Department of Environmental Science and Engineering Tsinghua University Beijing 10084 China3. J & K China Cleaning Energy Technology Co. Ltd. Beijing 100085 China

Biogas generated from sewage sludge,livestock waste,and food waste by anaerobic digestion is a valuable renewable energy ***,conventional anaerobic digestion is not an efficient process.A long hydraulic retention time and low biogas recovery rate hinder the applications of those *** effective pretreatment method to destroy sludge microbial cells has been one of the major concerns regarding improvement of the biogas *** article focuses on the effects of microwave heating on sludge anaerobic *** suspended solid(VSS) and chemical organic demand solubilization of heated sludge were *** heating was found to be a rapid and efficient process for releasing organic substrates from *** increase of organic dissolution ratio was not obvious when holding time was over 5 min with microwave *** effect of the VSS solubilization was primarily dependent on heating *** highest value of VSS dissolving ratio,3..4%,was obtained at 170°C for 3. *** COD dissolving ratio was about 25% at 170°*** organic carbon of treated sludge liquor was 1.98 and 2.73.g/L at 150°C and 170°C for 5 min,respectively.A biochemical methane potential(BMP) test of excess sludge and a mixture of primary and excess sludge demonstrated an increase in biogas *** total biogas from microwave treated mixture sludge increased by 12.9% to 20.2% over control after 3. days of *** production was 11.1% to 25.9% higher for excess sludge than for untreated *** VS removal ratios of mixture sludge and excess sludge were 12% and 11% higher,respectively,compared to the untreated sludge.

关键词： biogas recovery microwave heating sludge anaerobic digestion

Interfacial Microstructure and Properties of Ti(C, N)/Ni Bonded by Transient Liquid-phase Diffusion

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Journal of Wuhan university of technology(Materials science) 2009年第3期24卷 432-439页

作者：周世权熊惟皓 School of Mechanical science and Engineering Huazhong University of Science and Technology department of Mechanical Engineering University of Waterloo School of Materials science and Engineering Huazhong University of Science and Technology

Effects of the main process parameters（temperature and time） on microstructure and properties of Ti（C, N）/Ni interface bonded by （Cu＋Nb） interlayer in a vacuum diffusion bonding device were investigated. The interfacial microstructures consisted initially of Ni3.b metallic compound and eutectic of Ni3.b ＋ CuNiss, and finally transformed to （Ti, Nb）（C, N）＋Ni3.b near Ti （C, N） and NiCuss ＋ Ni3.b near Ni when diffusion bonding temperature was 1 523.1 573.K. It was clear that Cu was a constituent in the transient liquid phase （TLP） into which Ni was dissolved by forming Cu-Ni transition liquid. Nb was dissolved in Cu-Ni transition liquid rapidly. Ti （C, N） conld be wetted by resultant Ni-Nb-Cu transient liquid phase which was followed by a little （Ti, Nb）（C, N） solid solution formed at interface. This increased the interface combining capability. Ultimately the interface shear strength was able to reach 140 MPa. The theoretle analysis and experimental results show that the growth of interfacial reaction layer Ni3.b accords with parabola law, and the activation energy of diffusion reaction is 115.0±0.5 kJ/mol, while the diffusion reaction speed constant is 12.53.mm/s^1/2.

关键词： vacuum diffusion bonding transient liquid phase (TLP) diffusion bonding interlayer activation energy

The age of synthesis:From cognitive science to converging technologies and hereafter

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Chinese science Bulletin 2011年第6期56卷 465-475页

作者： CAI ShuShan1,2 1 department of Psychology, tsinghua university, Beijing 10084, china 2 Center for Psychology and Cognitive {3., tsinghua university, Beijing 10084, china department of Psychology Tsinghua University Center for Psychology and Cognitive science Tsinghua University

This paper describes the development of two of the most important scientific disciplines in the last quarter of the 20th century, cognitive science, which emerged in 1975, and nano-bio-info-cogno (NBIC) converging technologies, which emerged in 2000. In this century, we will achieve cross-disciplinary integration, innovation in comprehensive knowledge and comprehensive devel opment in human resources. NBIC converging technologies will greatly expand human cognition and communication, improve human health, enhance social outcomes, strengthen national security and unify science and education. Cognitive science and converging technologies will have major effects on the future human development. I argue that the 21st century represents an age of synthesis, reflected in the continual reintegration between scientific disciplines in recent times. This new age of synthesis will require innovations in thought and methodology that differ from those underlying the age of analysis in the 20th century. I predict that these developments will allow every individual to realize comprehensive development. Accordingly, the education system will be transformed, and a comprehensive human resources system will be created.

关键词：认知科学融合技术化学合成教育系统人力资源人类健康生物信息综合知识

Mining and Integrating Reliable Decision Rules for Imbalanced Cancer Gene Expression Data Sets

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tsinghua science and technology 2012年第6期17卷 666-673页

作者： Hualong Yu 1 , Jun Ni 2 , Yuanyuan Dan 3., Sen Xu 4 1. School of computer science and Engineering, Jiangsu university of science and technology, Zhenjiang 212003. china 2. department of Radiology, Carver College of Medicine, The university of Iowa, Iowa City, IA 52242, USA 3. School of Biology and Chemical Engineering, Jiangsu university of science and technology, Zhenjiang 212003. china 4. School of Information Engineering, Yancheng Institute of technology, Yancheng 224051, china School of computer science and Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China|c|

There have been many skewed cancer gene expression datasets in the post-genomic era. Extraction of differential expression genes or construction of decision rules using these skewed datasets by traditional algorithms will seriously underestimate the performance of the minority class, leading to inaccurate diagnosis in clinical trails. This paper presents a skewed gene selection algorithm that introduces a weighted metric into the gene selection procedure. The extracted genes are paired as decision rules to distinguish both classes, with these decision rules then integrated into an ensemble learning framework by majority voting to recognize test examples; thus avoiding tedious data normalization and classifier construction. The mining and integrating of a few reliable decision rules gave higher or at least comparable classification performance than many traditional class imbalance learning algorithms on four benchmark imbalanced cancer gene expression datasets.

关键词： cancer gene expression data class imbalance paired differential expression genes decision ruleensemble learning majority voting

A new heuristic algorithm for the circular packing problem with equilibrium constraints

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science china(Information sciences) 2011年第8期54卷 1572-1584页

作者： LIU JingFa 1,2,LI Gang 3.& GENG HuanTong 1 1 School of computer and Software,Nanjing university of Information science & {3.,Nanjing 210044,china 2 Network Information Center,Nanjing university of Information science & {3., Nanjing 210044,china 3.School of Mathematics and Physics,Nanjing university of Information science & {3.,Nanjing 210044,china 1. School of computer and Software Nanjing University of Information Science & Technology Nanjing 210044 China2. Network Information Center Nanjing University of Information Science & Technology Nanjing 210044 China3. School of Mathematics and Physics Nanjing University of Information Science & Technology Nanjing 210044 China

The circular packing problem with equilibrium constraints is an optimization problem about simplified satellite module layout design.A heuristic algorithm based on tabu search is put forward for solving this *** algorithm begins from a random initial configuration and applies the gradient method with an adaptive step length to search for the minimum energy *** jump out of the local minima and avoid the search doing repeated work,the algorithm adopts the strategy of tabu *** the process of tabu search,we improve the traditional neighboring solutions,tabu objects and the acceptance criteria of the current solution *** test two sets of benchmarks consisting of 11 representative instances from the current *** numerical results show that the proposed algorithm breaks the records in seven out of 11 instances,and obtains the optimal solutions for the other four instances.

关键词： equilibrium constraints packing problem heuristic algorithm tabu search layout optimization

THE GROWTH THEOREM FOR STARLIKE MAPPINGS ON BOUNDED STARLIKE CIRCULAR DOMAINS

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Chinese Annals of Mathematics,Series B 1998年第4期19卷 401-408页

作者： LIU TAISHUN (department of Mathematics, university of science and {3. of china, Hefei 23.026, china)REN GUANGBIN (department of Mathematics, university of science and {3. of china, Hefei 23.026, china) Univ Sci & Technol china Dept Math Anhua 230026 Peoples R China

The authors obtain the growth and covering theorem for the class of normalized biholomorphic starlike mappings on bounded starlike circular *** type of domain discussed is rather general, since the domain must be starlike if there exists a normalized biholomorphic starlike mapping on it. In the unit disc, it is just the famous growth and covering theorem for univalent *** theorem successfully realizes the initial idea of H. Cartan about how to extend geometric function theory from one variable to several complex variables.

关键词： Starlike mappings Growth theorem Starlike circular domains

Development of silicon-based microelectrode array

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science china(Technological sciences) 2009年第8期52卷 2391-2395页

作者： LIN JianHui1,2,3. WU XiaoMing1,2,3.4, HUANG PengSheng1,2, FENG Lei5, REN TianLing1,2 & LIU LiTian1,2 1 Institute of Microelectronics, tsinghua university, Beijing 100084, china 2 tsinghua National Laboratory for Information {3. and technology, Beijing 100084, china 3.Yangtze Delta Region Institute of tsinghua university, Jiaxing 3.4050, china 4 State Key Laboratory of Transducer technology, Chinese Academy of {3.s, Shanghai 200050 china 5 department of Biomedical Engineering, tsinghua university, Beijing 100084, china 1. Institute of Microelectronics Tsinghua University Beijing 100084 China 2. tsinghua National Laboratory for Information science and technology Beijing 100084 China 3. Yangtze Delta Region Institute of tsinghua university Jiaxing 314050 China 4. State Key Laboratory of Transducer technology Chinese Academy of Sciences Shanghai 200050 China 5. department of Biomedical Engineering Tsinghua University Beijing 100084 China

This paper introduces in details a kind of silicon-based microelectrode array. MEMS (micro-electromechanical system) technology is used in the fabrication of the microelectrode array, which is designed to perform signal recording and electrical stimulation for nerves in neural engineering. A simple fabrication process is developed. An improved model of microelectrodes is brought forward and successfully validated by the excellent match between circuit simulations and electrical measurements, including both magnitude and phase of microelectrode impedance. Compared with the simple one that is usually used, the improved model is believed to be an advance and more accurate. This modeling helps to improve the design of microelectrodes and understand the behavior of interface between electrode and cell. Furthermore, the microelectrode is proved to be a feasible tool for researches in neural engineering by successfully recording neural activities of sciatic nerve of a bullfrog.

关键词： microelectrode array MEMS neural engineering