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New evidence for lack of CMB power on large scales

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science China(Physics,Mechanics & Astronomy) 2010年第3期53卷 567-570页

作者： LIU Hao1 & LI TiPei1,2.3 1 Key laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of sciences, Beijing 100049, China 2.Department of Physics & Center for Astrophysics,{2., Beijing 100084, China 3 Department of Engineering Physics & Center for Astrophysics,{2., Beijing 100084, China Key laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China Department of Physics & Center for Astrophysics Tsinghua University Beijing China Department of Engineering Physics & Center for Astrophysics Tsinghua University Beijing China

A digitalized temperature map is recovered from the first light sky survey image published by the Planck team, from which an angular power spectrum of the cosmic microwave background (CMB) is derived. The amplitudes of the low multipoles (low-l) measured from the preliminary Planck power spectrum are significantly lower than those reported by the WMAP team. Possible systematical effects are far from enough to explain the observed low-l differences.

关键词： cosmology cosmic microwave background data analysis

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Fault prediction model based on evidential reasoning approach

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science China(information sciences) 2010年第10期53卷 2032-2046页

作者： SI XiaoSheng 1,2., HU ChangHua 1 & ZHOU ZhiJie 1,2.1 Unit 302. Xi’an Institute of Hi-Tech, Shaanxi, Xi’an 71002., China 2.Department of Automation, tsinghua university, Beijing 100084, China Unit 302 Xi’an Institute of Hi-Tech Shaanxi Xi’an China Department of Automation Tsinghua University Beijing China

In order to deal with fault prediction problems that involve both quantitative and qualitative in-formation for nonlinear complex system, a new fault prediction model is established based on the evidential reasoning (ER) approach, and an optimal learning algorithm for training ER-based prediction model is pre-sented based on the mean square error (MSE) criterion. This prediction model inherits the advantages of ER approach, which can deal with precise data, incomplete data and fuzzy data with nonlinear characteristic. In this model, the input signals transformed using rule based information transformation technique, are aggregated by analytical ER approach, and then the outputs of prediction model are constructed according to the types of system outputs. In addition, two fault decision criteria are defined to conduct fault identification. To overcome the difficulty in determining model parameters accurately and subjectively, a nonlinear optimization model is constructed and the optimal parameters are obtained. Two experimental studies are conducted to evaluate the performance of the proposed model. The results show that the established prediction model and the presented parameters optimization methods can deal with fault prediction problem effectively.

关键词： fault prediction evidential reasoning belief distribution nonlinear optimization

A measurement error model for microarray data analysis

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Progress in Natural science:Materials International 2005年第7期15卷 614-620页

作者： ZHOU Yiming and CHENG Jing ( Department of Biological sciences and Biotechnology, tsinghua university, Beijing 100084, China State Key {2. of Biomembrane and Membrane Biotechnology, tsinghua university, Beijing 100084, China national Engineering Research Center for Beijing Biochip Technology, 18 Life science Parkway, Beijing 102.06, China) Department of Biological sciences and Biotechnology Tsinghua University Beijing 100084 China State Key laboratory of Biomembrane and Membrane Biotechnology Tsinghua University Beijing 100084 China national Engineering Research Center for Beijing Biochip Technology 18 Life Science Parkway Beijing 102206 China

Microarray technology has been widely used to analyze the gene expression levels by detecting fluorescence intensity in a high throughput fashion. However, since the measurement error produced from various sources in microarray experiments is heterogeneous and too large to be ignored, we propose here a measurement error model for microarray data processing, by which the standard deviation of the measurement error is demonstrated to be linearly increased with fluorescence intensity. A robust algorithm, which estimates the parameters of the measurement error model from a single microarray without replicated spots, is provided. The model and algorithm for estimating of the parameters from a given data set are tested on both the real data set and the simulated data set, and the result has been proven satisfactory. And, combining the measurement error model with traditional Z-test method, a full statistical model has been developed It can significantly improve the statistical inference for identifying differentially expressed genes.

关键词： microarray measurement error model parameter estimation differentially expressed genes.

A hybrid matching method for geospatial services in a composition-oriented environment

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science China(Technological sciences) 2010年第S1期53卷 213-220页

作者： LUO An 1,2.WANG YanDong 1,2.& CHEN ShengHua 2.1 State Key laboratory of Software Engineering,Wuhan university,Wuhan 430072.China 2.State Key laboratory of information Engineering in Surveying,Mapping and Remote Sensing,Wuhan university,Wuhan 430079,China State Key laboratory of Software Engineering Wuhan University Wuhan China State Key laboratory of information Engineering in Surveying Mapping and Remote Sensing Wuhan University Wuhan China

With the development of Internet and GIS,large volumes of spatial data,powerful computing resources and many spatial data processing functions are published in the form of Web *** suitable geospatial services in the composition-oriented environment is a crucial *** semantic Web provides a kind of technology to find and compose various service resources automatically through the *** paper proposes a hybrid method for the semantic matching of geospatial *** method includes two *** 1 puts forward a multi-level semantic matching approach,which matches single geospatial service at four levels:classification,input/output,precondition/effect and the quality of service(QoS).This multi-level matching approach makes single service matching quicker and more *** 2.puts forward a matching algorithm for a geospatial service chain based on the *** algorithm adopts a trace algorithm,taking account of the effect of the *** restricts the input/output parameters of the current service by the input/output parameters of service chain,pre-service and *** matches the atomic service dynamically in a composition-oriented environment,and accurately converts the abstract model of geospatial services into an executable geospatial service chain.A case study of the flood analysis for the Poyang Lake illustrates the effectiveness of our context-based matching method for geospatial services.

关键词： geospatial services semantic context composition service match

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Lp shape deformation

science China(information sciences) 2012年第5期55卷 983-993页

作者： GAO Lin1,ZHANG GuoXin 1 & LAI YuKun 2.1 Department of Computer science and Technology,tsinghua {2.,Beijing 100084,China 2.School of Computer science and Informatics,Cardiff {2.,Wales CF2. 3AA,UK Department of Computer science and Technology Tsinghua University Beijing China School of Computer science and Informatics Cardiff University Wales UK

Shape deformation is a fundamental tool in geometric *** methods consider preserving local details by minimizing some energy functional measuring local distortions in the L 2.*** strategy distributes distortions quite uniformly to all the vertices and penalizes ***,there is no unique answer for a natural deformation as it depends on the nature of the *** by recent sparse signal reconstruction work with non L 2.norm,we introduce general L p norms to shape deformation;the positive parameter p provides the user with a flexible control over the distribution of unavoidable *** with the traditional L 2.norm,using smaller p,distortions tend to be distributed to a sparse set of vertices,typically in feature regions,thus making most areas less distorted and structures better *** the other hand,using larger p tends to distribute distortions more evenly across the whole *** flexibility is often desirable as it mimics objects made up with different *** specifying varying p over the shape,more flexible control can be *** demonstrate the effectiveness of the proposed algorithm with various examples.

关键词： shape deformation Lp norm geometric modeling

Multiparty quantum secret sharing of classical and quantum messages

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Progress in Natural science:Materials International 2007年第1期17卷 26-31页

作者： CHEN Pan, DENG Fuguo and LONG Guilu ( Key laboratory for Quantum information and Measurements, and Department of Physics,{2., Beijing 100084, China Key laboratory of Beam Technology and Material Modification, MOE, Institute of Low Energy Nuclear Physics, and Department of Material science and Engineering, Beijing Normal university, Beijing 100875, China Beijing Radiation Center, Beijing 100875, China Key laboratory for Atomic and Molecular Nano-sciences,{2., Beijing 100084, China) Key laboratory for Quantum information and Measurements Department of Physics Tsinghua University Beijing 100084 China Key laboratory of Beam Technology and Material Modification Beijing Normal University Beijing 100875 China Institute of Low Energy Nuclear Physics Department of Material Science and Engineering Beijing Normal University Beijing 100875 China Beijing Radiation Center Beijing 100875 China Key laboratory for Atomic and Molecular Nano-sciences Tsinghua University Beijing 100084 China

A scheme for multiparty quantum secret sharing of classical and quantum messages is proposed by using entanglement swapping. This scheme can distribute not only the classical information but also the quantum informati... 详细信息

关键词： quantum secret sharing classical message quantum message EPR pair.

Effect of streambed sediment on benthic ecology

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International Journal of Sediment Research 2009年第3期24卷 325-338页

作者： Xuehua DUAN1, Zhao-Yin WANG2. Mengzhen XU3, and Kang ZHANG41 Ph.D., Jiangyin Environmental Monitoring Station, Jiangyin 2.4431, China, Dept. of Hydraulic Engineering, tsinghua university,2.Prof., State Key laboratory of Hydro{2. and Engineering, tsinghua university, Beijing 100084, China, 3 Doctoral candidate, State Key laboratory of Hydro{2. and Engineering, tsinghua university, Beijing 100084, China,4 Doctoral candidate, State Key laboratory of Hydro{2. and Engineering, tsinghua university, Beijing 100084, China Ph.D. Jiangyin Environmental Monitoring Station Jiangyin 214431 China Dept. of Hydraulic Engineering Tsinghua University Prof. State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China Tel: 86-10-62773448(O) Doctoral candidate State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China

Benthic macroinvertebrates have been commonly used as indicator species for assessment of aquatic ecology. Streambed sediment, or substrate, plays an important role in habitat conditions for macroinvertebrate communities. Field investigations were done to study the benthic diversity and macroinvertebrate compositions in various stream substrata. Sampling sites with different bed sediment, latitude, and climate were selected along the Yangtze River, the Yellow River, the East River, and the Juma River, in China. The results show that benthic community structures found in different substrata clearly differ, while those found in substrata of similar composition and flow conditions but in different macroclimates are similar. The study, thus, demonstrates that the benthic macroinvertebrate community is mainly affected by substrate composition and flow conditions, but is generally unaffected by latitudinal position and macroclimate. Taxa richness of the macroinvertebrate community was found to be the highest on hydrophyte-covered cobbles, high on moss-covered bedrock, and low on clay beds and cobble beds devoid of plant biomass. Sandy beds are compact and unstable, thus, no benthic macroinvertebrates were found colonizing such substrata. Aquatic insects account for most of the macroinvertebrates collected in these rivers. Different insects dominate in different types of substrata: mainly EPT species (Ephemeroptera, Plecoptera, Trichoptera) in cobble, gravel, and moss-covered bedrock; and Chironomidae larvae in clay beds. The relation between the number of species in the samples and the size of the sampling area fits a power function of the species area. One square meter (1m2. is suggested as the minimum sampling area. A substrate suitability index is proposed by integrating the suitability of sediment, periphyton, and benthic organic materials for macroinvertebrates. The biodiversity of macroinvertebrates increases linearly with the substrate suitability index. Benthic ta

关键词： Streambed sediment Macroinvertebrates Benthic ecology Substrate suitability Biodiversity

Restrictive mechanism of flow control among non-cooperative Internet users

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science China(information sciences) 2011年第1期54卷 12-22页

作者： TAO Jun1,2.ZHONG Xiao1,2.& LU YiFei1,2.1Key laboratory of Computer Network and information Integration,Southeast {2., Ministry of Education,Nanjing 2.0096,China 2.chool of Computer science and Engineering,Southeast {2.,Nanjing 2.0096,China Key laboratory of Computer Network and information Integration Southeast University Ministry of Education Nanjing China School of Computer science and Engineering Southeast University Nanjing China

The flow and congestion control methods based on one-shot game model with non-cooperative game theory can explain the non-cooperative behavior of Internet ***,the low effciency of equilibrium solutions affects their *** the behavior of flow and congestion control based on infinitely repeated game models is addressed;the repeated and infinitely repeated flow and congestion control game model is presented; the existence and optimization of the Nash equilibrium point are proved;the discount factor in repeated game is discussed;the punishment and threat strategy to users'misbehavior is studied in N-users infinitely flow control game;the punishment restrictive method of users'behavior is designed in infinitely and finitely games;finally,a flow control algorithm based on repeated game,FCAR,is provided based on the conclusions of repeated game *** results of experiment and simulation show that FCAR algorithm could regularize and restrict users' misbehavior *** algorithm can also make non-cooperative Internet users achieve cooperation in order to optimize the utility of the whole flow and congestion control system.

关键词： Nash equilibrium utility infinitely and finitely repeated game flow and congestion control

Predistortion of high speed optical OFDM signal for aliasing-free receiving in multiple low-bandwidth receiver system

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Chinese Optics Letters 2010年第4期8卷 377-380页

作者：程林闻和郑小平张汉一郭奕理 State Key laboratory on Integrated Optoelectronics/tsinghua {2. laboratory for information science and Technology Department of Electronic EngineeringTsinghua University

A cost-effective method of multi-receiver optical orthogonal frequency-division multiplexing（OOFDM） system is proposed to reduce the requirement for the speed of the receiver and the size of fast Fourier transform（FFT）.The sampling rate of analog-to-digital converters（ADCs） can be reduced to 1/N of the original signal bandwidth in an N-receiver *** by signal predistortion at the transmitter, aliasing-free signal can be retrieved independently and directly at the low speed receivers.A back-to-back experimental result is given for a two-receiver *** effect of the electrical filters added before the ADC is studied and the analysis for filters optimization is given.

关键词： Cost reduction Fast Fourier transforms Orthogonal frequency division multiplexing

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