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Clustering-based hyperspectral band selection using sparse nonnegative matrix factorization

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Journal of zhejiang university-science C(Computers and Electronics) 2011年第7期12卷 542-549页

作者： Ji-ming LI 1,2,Yun-tao QIAN 1 (1 School of Computer science and technology,zhejiang university,hangzhou 310027,china) (2 zhejiang Police college,hangzhou 310053,china) School of Computer science and technology Zhejiang University zhejiang Police college

Hyperspectral imagery generally contains a very large amount of data due to hundreds of spectral *** selection is often applied firstly to reduce computational cost and facilitate subsequent tasks such as land-cover classification and higher level image *** this paper,we propose a new band selection algorithm using sparse nonnegative matrix factorization (sparse NMF).Though acting as a clustering method for band selection,sparse NMF need not consider the distance metric between different spectral bands,which is often the key step for most common clustering-based band selection *** imposing sparsity on the coefficient matrix,the bands' clustering assignments can be easily indicated through the largest entry in each column of the *** results showed that sparse NMF provides considerable insight into the clustering-based band selection problem and the selected bands are good for land-cover classification.

关键词： Hyperspectral Band selection Clustering Sparse nonnegative matrix factorization

Approximate merging of multiple Bézier segments

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Progress in Natural science:Materials International 2008年第6期18卷 757-762页

作者： Min Chenga,b,Guojin Wanga,* aInstitute of Computer Graphics and Image Processing,zhejiang university,hangzhou 310027,china bcollege of science,zhejiang university of technology,hangzhou 310032,china Institute of Computer Graphics and Image Processing Zhejiang University Hangzhou 310027 China college of science Zhejiang University of Technology Hangzhou 310032 China

This paper deals with the approximate merging problem of multiple adjacent Bézier curves with dierent degrees by a single Bézier curve,which is a frequently seen problem in *** unified matrix representation for precise merging is presented and the approx-imate merging curve is further derived based on matrix *** at the endpoints of curves is also discussed in the merging *** show that the method in this paper achieves satisfying merging results.

关键词： Computer-aided geometric design Bézier curve Approximate merging Matrix representation

Lp-dual Quermassintegral sums

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science china Mathematics 2007年第9期50卷 1347-1360页

作者： Chang-jian ZHAO Department of Information and Mathematics sciences,college of science,china Jiliang university,hangzhou 310018,china 1. Department of Information and Mathematics sciences College of Science China Jiliang University Hangzhou 310018 China

In this paper,we first introduce a concept of L_p-dual Quermassintegral sum function of convex bodies and establish the polar projection Minkowski inequality and the polar projection Aleksandrov-Fenchel inequality for L_p-dual Quermassintegral ***,by using Lutwak’s width-integral of index i,we establish the L_p-Brunn-Minkowski inequality for the polar mixed projec- tion *** applications,we prove some interrelated results.

关键词： mixed volumes mixed projection bodies dual Quermassintegral sum polar of mixed projection bodies 52A40 53A15

Variations in Laboratory-Scale Actinomycete Communities Exposed to Cadmium as Assessed by Denaturing Gradient Gel Electrophoresis Profiles

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Pedosphere 2010年第2期20卷 174-184页

作者： YUAN Hai-Ping,MIN Hang 2,LIU Ji,YAN Bo and L Zhen-Mei college of life science,zhejiang university,hangzhou 310058 (china) [a] college of life science Zhejiang University Hangzhou 310058 (China)

The actinomycete populations and functions in cadmium （Cd） contaminated soil were investigated by the cultivation- independent molecular methods. The genomic DNA was extracted and purified from soil adulterated with various con- centrations of Cd in the laboratory. The partial 16S rDNA genes were amplified by polymerase chain reaction （PCR） using specific primers bound to evolutionarily conserved regions within these actinomycete genes. The diversity in PCR- amplified products, as measured by denaturing gradient gel electrophoresis （EGGE）, was used as a genetic fingerprint of the population. Principle component analysis and Shannon-Weaver diversity index （H） analyses were used to analyze the DGGE results. Results showed that the two principal components accounted for only a low level of the total variance. The value H in contaminated soil was lower than that in the control at later stages of cultivation, whereas at earlier stages it was higher. Among the six sampling time points, the first, fifth and sixth weeks had the highest values of H. Significantly negative correlations between bioavallable Cd concentration and H values existed in the samples from weeks 2 （R = 0.929, P 〈 0.05） and 4 （R = 0.909, P 〈 0.05）. These results may shed light on the effect of Cd on the soil environment and the chemical behavior and toxicity of Cd to actinomycetes.

关键词： denaturing gradient gel electrophoresis genes principal component analysis Shannon-Weaver diversity index

A general communication performance evaluation model based on routing path decomposition

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Journal of zhejiang university-science C(Computers and Electronics) 2011年第7期12卷 561-573页

作者： Ai-lian CHENG 1,Yun PAN 1,2,Xiao-lang YAN 2,Ruo-hong HUAN 3 (1 Department of Information science and Electronic Engineering,zhejiang university,hangzhou 310027,china) (2 Institute of VLSI Design,zhejiang university,hangzhou 310027,china) (3 college of Computer science and technology,zhejiang university of technology,hangzhou 310023,china) Department of Information science and Electronic Engineering Zhejiang University Institute of VLSI Design Zhejiang University

The network-on-chip (NoC) architecture is a main factor affecting the system performance of complicated multi-processor systems-on-chips (MPSoCs).To evaluate the effects of the NoC architectures on communication efficiency,several kinds of techniques have been developed,including various simulators and analytical *** simulators are accurate but time consuming,especially in large space explorations of diverse network configurations;in contrast,the analytical models are fast and flexible,providing alternative methods for performance *** this paper,we propose a general analytical model to esti-mate the communication performance for arbitrary NoCs with wormhole routing and virtual channel flow *** resolve the inherent dependency of successive links occupied by one packet in wormhole routing,we propose the routing path decomposition approach to generating a series of ordered link *** we use the traditional queuing system to derive the fine-grained transmission latency for each network *** to our experiments,the proposed analytical model provides a good approximation of the average packet latency to the simulation results,and estimates the network throughput precisely under various NoC configurations and ***,the analytical model runs about 10 5 times faster than the cycle-accurate NoC *** applications of the model including bottleneck detection and virtual channel allocation are also presented.

关键词： Analytical model Communication performance Network-on-chip (NoC) Queuing system Routing path decom-position Virtual channel

Synthesis and crystal structure of complex of Ce(NO_3)_3 with N-(3-methyl-pyridin-2-yl)-formimidoyl-(3-methyl-pyridin-2-yl) hydrazone

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science china Chemistry 2004年第3期47卷 251-256页

作者： JIANG Yinzhi1,2 & HU Weixiao1 1. Department of Pharmaceutical science, zhejiang university of technology, hangzhou 310032, china 2. Department of Applied Chemistry, zhejiang Institute of science and technology, hangzhou 310033, china 1. Department of Pharmaceutical science Zhejiang University of Technology 310032 Hangzhou China 2. Department of Applied Chemistry Zhejiang Institute of Science and Technology 310033 Hangzhou China

The reaction of 3,6-di-(3-methyl-pyridin-2-yI)-s-tetrazine (DMPTZ, II) with CeIII salt [Ce(NO3)3 · 6H2O] generates a new ligand, N-(3-methyl-pyridin-2-yl)-formimidoyl-(3-methyl-pyridin-2-yl) hydrazone (L), and forms a new complex: a mononuclear complex [Ce(L)(NO3)2 (H2O)3] · NO3 (III). Crystal data for III: space group P-1, with a = 0.7133(4) nm, b = 1.1139(2) nm, c = 1.4572(3) nm, α= 102.13(2)°, β= 99.81(3)°, γ= 91.10(3)°, Z = 2, V = 1113.6(7) nm3, μ = 2.123 mm?1 and F(000) = 630. L acts as a tri-dentate chelating ligand in III. There are 10 coordination sites around Ce3+ of III, which are respectively occupied by seven oxygen atoms (four from two nitrate anions and three from three H2O molecules) and three nitrogen atoms (all from L). The cerium atom and three chelating nitrogen atoms are coplanar. The mechanism of the metal assisted decomposition is discussed briefly.

关键词： rare earth, complex, crystal structure, synthesize, 3,6-bis (3-methyl-pyridin-2-yl)-s-tetrazine, N-(3-methyl-pyridin- 2-yl)-formimidoyl-(3-methyl-pyridin-2-yl) hydrazone.

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 university of science and technology, Wuhan 430074, 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

Irrigation Water Use Efficiency of Farmers and Its Determinants: Evidence from a Survey in Northwestern china

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Agricultural sciences in china 2010年第9期9卷 1326-1337页

作者： WANG Xue-yuan college of Economics, zhejiang Gongshang university, hangzhou 310018, P.R.china [a] college of Economics Zhejiang Gongshang University Hangzhou 310018 P.R. China

Irrigation water shortage is becoming an increasingly serious problem in agricultural production. In this case, it is very important for policy makers to take measures to improve irrigation water use efficiency, especially in the water-scarce areas. In this paper, the data envelopment analysis （DEA） techniques, based on the concept of input-specific technical efficiency were used to develop farm-level technical efficiency measures and sub-vector efficiencies for irrigation water use. The Tobit regression technique was then adopted to identify the factors that influence irrigation water efficiency differentials under the shortage of water resources. Based on a sample data of 432 wheat farmers in northwestern china, our experimental results of the DEA analysis showed the average technical efficiency of 0.6151. It suggested that wheat farmers could increase their production by as much as 38.49% by using inputs more efficiently. Further, the mean irrigation water efficiency of 0.3065, suggested that wheat farmers could produce the same quantity of wheat using the same quantity of inputs but with 69.35% less water. The results of the Tobit regression analysis showed that the farmer＇s age, income, education level, and the farm size tended to affect the degree of irrigation water efficiency positively, and the channel conditions and different irrigation methods made a significant impact on irrigation water use efficiency. Furthermore, the arrangements of exclusive water property rights and competitive water price mechanism have effectively encouraged the water saving behavior of farmers. These results are valuable for policy makers since it could help to guide policies towards high irrigation water use efficiency.

关键词： irrigation water efficiency determinants data envelopment analysis Tobit regression

Occurrence of nitrification-denitrification and gaseous nitrogen loss process in flooded rice soil

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Progress in Natural science:Materials International 2007年第1期17卷 6-10页

作者： NI Wuzhong, LI Jianping and ZHU Zhaoliang (college of Environmental and Resource sciences, zhejiang university, hangzhou 310029, china college of Biosystems Engineering and Food science, zhejiang university, hangzhou 310029, china Institute of Soil science, Chinese Academy of sciences, Nanjing 210008, china) [a]Gllege of Environmental and Resmirce sciences Zheiang University Hangzhou China [b]Gllege of Biosystems Engineering and Food science Zheiang University Hangzhou China [c]Institute of Soil science Chinese Academy of Sciences Naning China

Flooding in wetland rice fields soon after transplanting results in displacement of soil air (including O2). Thus any dissolved O2 in the pore water is consumed out by microbial respiration in a short period. Supply of O2 to the flooded rice soil is by diffusion of O2 through the standing floodwater and consumption at the soil-water interface, and by exudation of O2 by rice roots and subsequent diffusion of O2 into the rhizosphere. The greater potential consumption of O2 compared to the renewal rate results in the development of distinct soil layers: oxidized soil layers under soil-water interface and in the rhizosphere, and reduced soil layers or reduced bulk soil. Nitrification in oxidized soils and denitrification in reduced soils have been known. Currently, denitrification in oxidized soils, even in standing floodwater, has also been identified. In this article, we present a modified nitrification and denitrification occurring mechanism in flooded rice soil.

关键词： denitrification flooded rice soil gaseous nitrogen loss nitrification.