检索结果-南通市图书馆

A measurement error model for microarray data analysis

在线全文

学校读者我要写书评

暂无评论

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 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) 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.

The relativistic consistent angular-momentum projected shell model study of the N=Z nucleus ^(52)Fe

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2009年第10期52卷 1471-1476页

作者： LI YanSong1,2 & LONG GuiLu1,2 1 Department of Physics,tsinghua university,Beijing 100084,China 2 Center of Nuclear Theory,national {3. of Heavy Ion Accelerator of Lanzhou,Lanzhou 73.000,China 1. Department of Physics Tsinghua University Beijing 100084 China 2. Center of Nuclear Theory National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou 730000 China

The relativistic consistent angular-momentum projected shell model(ReCAPS) is used in the study of the structure and electromagnetic transitions of the low-lying states in the N=Z nucleus *** model calculations show a reasonably good agreement with the *** backbending at 12+ is reproduced and the energy level structure suggests that neutron-proton interactions play important roles.

关键词： ReCAPS relativistic mean field angular-momentum projection method 52Fe neutron-proton interaction

Effect of streambed sediment on benthic ecology

在线全文

学校读者我要写书评

暂无评论

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 21443., China, Dept. of Hydraulic Engineering, tsinghua university,2 Prof., State Key laboratory of Hydroscience and Engineering, tsinghua university, Beijing 100084, China, 3.Doctoral candidate, State Key laboratory of Hydroscience and Engineering, tsinghua university, Beijing 100084, China,4 Doctoral candidate, State Key laboratory of Hydroscience and Engineering, tsinghua university, Beijing 100084, China [a] Ph.D. Jiangyin Environmental Monitoring Station Jiangyin 21443. China Dept. of Hydraulic Engineering tsinghua university [b] Prof. State Key laboratory of Hydroscience and Engineering tsinghua university Beijing 100084 China Tel: 86-10-62773.48(O) [c] Doctoral candidate State Key laboratory of Hydroscience and Engineering tsinghua university Beijing 100084 China [d] 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

SQUARE attack on block ciphers with low algebraic degree

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science China(information sciences) 2010年第10期53卷 1988-1995页

作者： SUN Bing 1 , LI RuiLin 1 , QU LongJiang 1,3.& LI Chao 1,2,3.1 science College of national university of Defense Technology, Changsha 410073. China 2 State Key {3. of information Security, Graduate university of Chinese Academy of sciences, Beijing 100049, China 3.national Mobile Communications Research {3., Southeast university, Nanjing 210096, China 1. science College of national university of Defense Technology Changsha 410073 China3. National Mobile Communications Research Laboratory Southeast University Nanjing 210096 China2. State Key Laboratory of Information Security Graduate University of Chinese Academy of Sciences Beijing 100049 China

By using an algebraic method, the mathematical foundation of SQUARE attack is studied in this paper. We point out that a SQUARE distinguisher exists if and only if the degree of the polynomial function between n-bit input which is active and n-bit output which is balanced is 2 n-2. And the algebraic method can also be used to determine the property of a balanced set after passed through a nonlinear S-box, by which in some cases we can find a SQUARE distinguisher with more rounds. The validity of SQUARE attack and the influence of the choice of S-box are also studied. If the round function of a Feistel cipher has a low algebraic degree, a SQUARE attack cannot recover the right keys in some special cases. However, SQUARE attack on SPN ciphers always holds. The relations among SQUARE attack and some other cryptanalytic method are studied, showing that if a cipher is breakable by SQUARE attack, then it is also breakable by the interpolation attack.

关键词： SQUARE attack interpolation attack integral attack block cipher

Multiparty quantum secret sharing of classical and quantum messages

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

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, tsinghua university, 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, tsinghua university, Beijing 100084, China) [a]Key laboratory for Quantum information and Measurements and Department of Physics Tsinghua University Beijing China [b]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 China [c]Beijing Radiation Center Beijing China [d]Key laboratory for Atomic and Molecular Nano-sciences Tsinghua University Beijing 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.

Microstructures and characteristics of deep trap levels in ZnO varistors doped with Y_2O_3

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science China(Technological sciences) 2009年第12期52卷 3668-3673页

作者： LIU Jun 1 ,HU Jun 1 ,HE JinLiang 1 ,LIN YuanHua 2 &LONG WangCheng 1 1State Key laboratory of Power Systems,Department of Electrical Engineering,tsinghua university,Beijing 100084,China 2State Key laboratory of New Ceramics and Fine Processing,Department of Material science and Engineering,tsinghua university, Beijing 100084,China 1. State Key laboratory of Power Systems Department of Electrical Engineering Tsinghua University Beijing 100084 China 2. State Key laboratory of New Ceramics and Fine Processing Department of Material Science and Engineering Tsinghua University Beijing 100084 China

In this paper discussions on ZnO based varistor ceramics doped with different ratios of Y2O3.are *** on the phase and microstructures of the samples indicates that an additional phase is detected in the samples doped with Y2O3.and the average grain size of the specimens decreases from about 9.2μm to 4.5μm,with an increase in the addition of Y2O3.from 0 mol%to 3.mol%.The corresponding varistor’s voltage gradient markedly increases from 462 V/mm to 23.0 V/mm,while the nonlinear coefficient decreases from 22.3.to 11.5,***,the characteristics of deep trap levels in these ZnO samples are investigated by measuring their dielectric *** trap energy level and capture cross section evaluated by relaxation peak of the Cole-Cole plot vary slightly as the addition of Y2O3.*** traps may be ascribed to the intrinsic defects of ZnO lattice.

关键词： ZnO varistors Y2O3 electrical properties deep trap levels

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

在线全文

学校读者我要写书评

暂无评论

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 national 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

Dense coding scheme using superpositions of Bell-states and its NMR implementation

在线全文

学校读者我要写书评

暂无评论

science China(Physics,Mechanics & Astronomy) 2005年第1期48卷 57-67页

作者： ZHANG Jingfu, XIE Jingyi, DENG Zhiwei & LU Zhiheng Key laboratory for Quantum information and Measurements, Department of Physics, tsinghua university, Beijing 100084, China Center for Quantum information, tsinghua university, Beijing 100084, China Department of Materials science and Engineering, Beijing Normal university, Beijing 100875, China Testing and Analytical Center, Beijing Normal university, Beijing 100875, China Department of Physics, Beijing Normal university, Beijing 100875, China 1. Key laboratory for Quantum information and Measurements Department of Physics Tsinghua University 100084 Beijing China 2. Center for Quantum information Tsinghua University 100084 Beijing China 3. Department of Materials science and Engineering Beijing Normal University 100875 Beijing China 4. Testing and Analytical Center Beijing Normal University 100875 Beijing China 5. Department of Physics Beijing Normal University 100875 Beijing China

Dense coding using superpositions of Bell-states is proposed. The generalized Grover's algorithm is used to prepare the initial entangled states, and the reverse process of the quantum algorithm is used to determine the entangled state in the decoding measurement. Compared with the previous schemes, the superpositions of two Bell-states are exploited. Our scheme is demonstrated using a nuclear magnetic resonance (NMR)quantum computer. The corresponding manipulations are obtained. Experimental results show a good agreement between theory and experiment. We also generalize the scheme to transmit eight messages by introducing an additional two-state system.

关键词： dense coding, superpositions of Bell-states, generalized Grover's algorithm, nuclear magnetic res-onance, quantum computer.

On the number of rotation symmetric Boolean functions

在线全文

学校读者我要写书评

暂无评论

science China(information sciences) 2010年第3期53卷 537-545页

作者： FU ShaoJing1, LI Chao1,2 & QU LongJiang1,3.1science College of national university of Defense Technology, Changsha 410073. China 2State Key {3. of information Security, Beijing 10003., China 3.1} Mobile Communications Research {3., Southeast university, Nanjing 210096, China 1. science College of national university of Defense Technology Changsha 410073 China2. State Key Laboratory of Information Security Beijing 100039 China3. National Mobile Communications Research Laboratory Southeast University Nanjing 210096 China

Rotation symmetric Boolean functions (RSBFs) have been used as components of different cryptosystems. This class of functions are invariant under circular translation of indices. In this paper, we investigated balanced RSBFs and 1st order correlation immune RSBFs. Based on constructive techniques, we give an accurate enumeration formula for n-variable balanced RSBFs when n is a power of a prime. Furthermore, an original and efficient method to enumerate all n-variable (n prime) 1st order correlationimmune functions is presented. The exact number of 1st order correlation immune RSBFs with 11 variables is 69250471565504788252252503.4129764511077684773.05520800 and the number of 13.variables has 189 digits. Then for more variables, we also provide a significant lower bound on the number of 1st order correlation immune RSBFs.

关键词： cryptography rotation symmetry correlation immunity balancedness