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Polynomial analysis of canopy spectra and biochemical component content inversion

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Science china earth {2. 2005年第10期48卷 1780-1791页

作者： YAN Chunyan1, LIU Qiang1, NIU Zheng1, WANG Jihua2. HUANG Wenjiang2.& LIU Liangyun 2.1. State Key Laboratory of Remote Sensing Science, Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese academy of sciences and Beijing Normal {2., Beijing 100101, china 2. National Engineering research center for Information technology in Agriculture, Beijing 100089, china State Key Laboratory of Remote Sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese academy of sciences and Beijing Normal {2. Beijing china National Engineering research center for Information {2. in Agriculture Beijing china

A polynomial expression model was developed in this paper to describe directional canopy spectra, and the decomposition of the polynomial expression was used as a tool for re-trieving biochemical component content from canopy multi-angle spectra. First, the basic formula of the polynomial expression was introduced and the physical meaning of its terms and coeffi-cients was discussed. Based on this analysis, a complete polynomial expression model and its decomposition method were given. By decomposing the canopy spectra simulated with SAILH model, it shows that the polynomial expression can not only fit well the canopy spectra, but also show the contribution of every order scattering to the whole reflectance. Taking the first scattering coefficients a10 and a01 for example, the test results show that the polynomial coefficients reflect very well the hot spot phenomenon and the effects of viewing angles, LAI and leaf inclination angle on canopy spectra. By coupling the polynomial expression with leaf model PROSPECT, a canopy biochemical component content inversion model was given. In the simulated test, the canopy multi-angle spectra were simulated by two different models, SAILH and 4-SCALE re-spectively, then the biochemical component content was retrieved by inverting the coupled polynomial expression + PROSPECT model. Results of the simulated test are promising, and when applying the algorithm to measured corn canopy multi-angle spectra, we also get relatively accurate chlorophyll content. It shows that the polynomial analysis provides a new method to get biochemical component content independent of any specific canopy model.

关键词： polynomial expression, canopy spectra, decomposition, biochemical component content, inversion.

Prediction model for spring dust weather frequency in North china

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Science china earth {2. 2008年第5期51卷 709-720页

作者： LANG XianMei center for Disastrous Climate research and Prediction, Institute of Atmospheric Physics, Chinese {2. of sciences, Beijing 10002., china center for Disastrous Climate research and Prediction Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

It is of great social and scientific importance and also very difficult to make reliable prediction for dust weather frequency (DWF) in North china. In this paper, the correlation between spring DWF in Beijing and Tianjin observation stations, taken as examples in North china, and seasonally averaged surface air temperature, precipitation, Arctic Oscillation, Antarctic Oscillation, South Oscillation, near surface meridional wind and Eurasian westerly index is respectively calculated so as to construct a prediction model for spring DWF in North china by using these climatic factors. Two prediction models, i.e. model-I and model-II, are then set up respectively based on observed climate data and the 32.year (1970 -2.01) extra-seasonal hindcast experiment data as reproduced by the nine-level Atmospheric General Circulation Model developed at the Institute of Atmospheric Physics (IAP9L-AGCM). It is indicated that the correlation coefficient between the observed and predicted DWF reaches 0.933 in the model-I, suggesting a high prediction skill one season ahead. The corresponding value is high up to 0.948 for the subsequent model-II, which involves synchronous spring climate data reproduced by the IAP9L-AGCM relative to the model-I. The model-II can not only make more precise prediction but also can bring forward the lead time of real-time prediction from the model-I’s one season to half year. At last, the real-time predictability of the two models is evaluated. It follows that both the models display high prediction skill for both the interannual variation and linear trend of spring DWF in North china, and each is also featured by different advantages. As for the model-II, the prediction skill is much higher than that of original approach by use of the IAP9L-AGCM alone. Therefore, the prediction idea put forward here should be popularized in other regions in china where dust weather occurs frequently.

关键词： spring dust weather frequency prediction model iap9l-agcm hindcast experiment real-time prediction

Construction of WCB-11:A novel phiYFP arsenic-resistant whole-cell biosensor

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Journal of Environmental sciences 2010年第9期22卷 1469-1474页

作者： Qing Hu ,Li Li,Yanjuan Wang,Wenjuan Zhao,Hongyan Qi,Guoqiang Zhuang Department of Environmental Bio-technology,research {2. for Eco-Environmental sciences,Chinese academy of sciences,Beijing 100085,china. [a] Department of Environmental Bio-technology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

The prediction and assessment of environmental pollution by arsenic are important preconditions of advocating environmental protection and human health risk assessment. A yellow fluorescent protein-based whole-cell biosensor for the detection of arsenite and arsenate was constructed and tested. An arsenic-resistant promoter and the regulatory gene arsR were obtained by PCR from the genome ofEscherichia coli DH5ct, andphiYFP was introduced into E. coli DH5ct as a reporter gene to construct an arsenic-resistant whole-cell biosensor （WCB-11） in which phiYFP was expressed well for the first time. Experimental results demonstrated that the biosensor has a good response to arsenic and the expression ofphiYFP. When strain WCB-11 was exposed to As^3＋ and As^5＋, the expression of yellow fluorescence was time-dependent and dose-dependent. This engineered construct is expected to become established as an inexpensive and convenient method for the detection of arsenic in the field.

关键词： arsenic reporter gene whole-cell biosensor yellow fluorescent protein (phiYFP)

Theory of truth degrees of propositions in the logic system Ln^＊

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Science in china(Series F) 2006年第4期49卷 471-483页

作者： LI Jun1,2.& WANG Guojun1,3 1. Institute of Mathematics, Shaanxi Normal university, Xi’an 710062. china 2. School of {2., Lanzhou university of technology, Lanzhou 730050, china 3. research center for Science, Xi’an Jiaotong university, Xi’an 710049, china 1. Institute of Mathematics Shaanxi Normal University Xi’an 710062 China 2. School of sciences Lanzhou University of Technology Lanzhou 730050 China 3. research center for Science Xi’an Jiaotong University Xi’an 710049 China

By means of infinite product of uniformly distributed probability spaces of cardinal n the concept of truth degrees of propositions in the n-valued generalized Lu- kasiewicz propositional logic system Ln^＊ is introduced in the present paper. It is proved that the set consisting of truth degrees of all formulas is dense in [0,1], and a general expres- sion of truth degrees of formulas as well as a deduction rule of truth degrees is then obtained. Moreover, similarity degrees among formulas are proposed and a pseudo-metric is defined therefrom on the set of formulas, and hence a possible framework suitable for developing approximate reasoning theory in n-valued generalized Lukasiewicz propositional logic is established.

关键词： truth degree similarity degree approximate reasoning.

Oxidation Experiment of Natural Megacrystal Ch'nopyroxene: Implications for Assignment of Mossbauer Spectra

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Acta Geologica Sinica(English Edition) 2001年第1期 51-58页

作者： ZHI Xiachen, CHEN PengDepartment of earth and Space sciences, {2. of Science and technology of china Laboratory of Chemical Geodynamics, USTC advanced research center for earth Science and astronomy in USTC, third world {12. of Science, Hefei 2.002. LIN Chengzhong, CHEN Shuqing, ZHANG GuilanInstitute of Mineral Resources, Chinese {12. of Geology sciences, Beijing 100037LI Yuzhi and LIN Lei Open Laboratory of Structure Analysis, USTC, Hefei 2.002.

The Mossbauer spectra of natural megacrystal clinopyroxene are usually fitted by 4 sets of symmetric doublets, A-A', B-B', C-C' and D-D', respectively, in terms of increasing Qs value in literature. But the assignments of those doublets are quite different, except the D-D' doublet assigned to Fe3+ at the lattice site Ml in previous papers. Particularly, the assignment and interpretation of the C-C' doublet are *** oxidation experiments of natural megacrystal clinopyroxene collected from the Hannuoba basalt, North china, were performed under controlled conditions of temperature at 1000℃ and oxygen fugacity of FMQ buffer in 1, 2. 3 and 5 days respectively. The oxidized samples were then measured by X-ray diffraction spectrometry and Mossbauer spectrometry. The oxidation of clinopyroxene is characterized by Fe2.→ Fe3+ at Ml under the subsolidus conditions, which is consistent with the increase of the area of the D-D' doublet when the heating time increases. Accordingly, the area of the A-A' and B

关键词： megacrystal clinopyroxene Mossbauer spectrum oxidation experiment anomalous doublet

Lunar surface dielectric constant,regolith thickness, and ~3He abundance distributions retrieved from the microwave brightness temperatures of CE-1 Lunar Microwave Sounder

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Science china earth {2. 2010年第9期53卷 1365-1378页

作者： WANG ZhenZhan1, LI Yun1,2. JIANG JingShan1 & LI DiHui1 1 National Microwave Remote Sensing Laboratory, center for Space Science and Applied research, Chinese {2. of sciences, Beijing 100190, china 2.Graduate university of Chinese {2. of sciences, Beijing 100049, china 1. National Microwave Remote Sensing Laboratory Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100190 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

Lunar regolith parameters, such as physical temperature, thickness and dielectric constant, are important in studying regolith features, distribution of lunar resources and evolution of the Moon. There had been no measurement obtained by lunar-orbit-borne microwave radiometer applied to evaluate the properties of lunar regolith before CE-1 Lunar Microwave Sounder (CELMS) being launched. CEMLS is the first passive microwave radiometer in the world to sound the surface of the Moon. The brightness temperatures (TB) sensed by CELMS include complicated information on the above geophysical parameters. In this paper, algorithms of retrieving dielectric constant, regolith thickness, and 3He content from CELMS brightness temperatures are developed, and the results are compared with those from literature. The results show that the regolith thicknesses are mostly in the range of 4.0-6.0 m, and 43% of them are bigger than 5.0 m. The content of 3He evaluated by retrieved regolith thickness is about 1.03 million tons.

关键词： CE-1 Lunar Microwave Sounder (CELMS) lunar regolith dielectric constant lunar regolith thickness 3He retrieval

An analysis of the wide area differential method of geostationary orbit satellites

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Science china(Physics,Mechanics & astronomy) 2009年第2期52卷 310-314页

作者： CAI ChengLin1,2.3?, LI XiaoHui1 & WU HaiTao1 1 National Time Service center, Chinese academy of {2., Lintong 710600, china 2.Hunan Institute of Humanities, Science and technology, Loudi 417000, china 3 Graduate university of Chinese academy of {2., Beijing 100049, china 1. National Time Service center Chinese Academy of Sciences Lintong 710600 China 2. Hunan Institute of Humanities Science and Technology Loudi 417000 China 3. Graduate university of Chinese academy of {2. Beijing 100049 China

This work aims to obtain a wide area differential method for geostationary orbit (GEO) constellation. A comparison between the dilution of precision (DOP) of four-dimensional (4D) calculation including sa- tellite clock errors and ephemeris errors and that of three-dimensional (3D) calculation only including ephemeris errors with the inverse positioning theory of GPS shows the conclusion that all the 3D PDOPs are greatly reduced. Based on this, a basic idea of correcting satellite clock errors and ephem- eris errors apart is put forward, and moreover, a specific method of separation is proposed. Satellite clock errors are separated in a master station with time synchronization, and all the remaining pseu- do-range errors after the satellite clock errors have been deducted are used to work out ephemeris corrections of all GEO satellites. By a comparative analysis of user positioning accuracy before and after differential, the wide area differential method is verified to be quite valid for GEO constellation.

关键词： geostationary orbitsatellite dilution of precision satellite ephemeris errors satellite clock errors wide area differential method

A one-dimensional heat transfer model of the Antarctic Ice Sheet and modeling of snow temperatures at Dome A, the summit of Antarctic Plateau

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Science china earth {2. 2010年第5期53卷 763-772页

作者： CHEN BaiLian1,3, ZHANG RenHe2. SUN ShuFen1, BIAN LinGen2. XIAO CunDe4,2.& ZHANG TingJun5 1 Institute of Atmospheric Physics, Chinese academy of sciences, Beijing 10002., {2. 2.Chinese academy of Meteorological sciences, Beijing 100081, {2. 3 Graduate university of Chinese academy of sciences, Beijing 100049, {2. 4 Cold and Arid Regions Environmental and Engineering research Institute, Chinese academy of sciences, Lanzhou 730000, {2. 5 The National Snow and Ice Data center, university of Colorado, Boulder, CO 80309-0449, USA 1. Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China3. Graduate University of Chinese Academy of Sciences Beijing 100049 China2. Chinese Academy of Meteorological Sciences Beijing 100081 China4. Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China5. The National Snow and Ice Data Center University of Colorado Boulder CO 80309-0449 USA

A vertical one-dimensional numerical model for heat transferring within the near-surface snow layer of the Antarctic Ice Sheet was developed based on simplified parameterizations of associated physical processes for the atmosphere, radiation, and snow/ice systems. Using the meteorological data of an automatic weather station (AWS) at Dome A (80°2.′S, 70°2.′E), we applied the model to simulate the seasonal temperature variation within a depth of 2. m. Comparison of modeled results with observed snow temperatures at 4 measurement depths (0.1, 1, 3, 10 m) shows good agreement and consistent seasonal variations. The model results reveal the vertical temperature structure within the near-surface snow layer and its seasonal variance with more details than those by limited measurements. Analyses on the model outputs of the surface energy fluxes show that: 1) the surface energy balance at Dome A is characterized by the compensation between negative net radiation and the positive sensible fluxes, and 2. the sensible heat is on average transported from the atmosphere to the snow, and has an evident increase in spring. The results are considered well representative for the highest interior Antarctic Plateau.

关键词： Antarctic Ice Sheet near-surface layer energy transfer numerical model

Identifying heavy hitters in high-speed network monitoring

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Science china(Information sciences) 2010年第3期53卷 659-676页

作者： ZHANG Yu1, FANG BinXing1,2.& ZHANG YongZheng2.1research center of Computer Network and Information Security {2., Harbin Institute of {2., Harbin 150001, china 2.0} center of Information Security, Institute of Computing {2., Chinese academy of sciences, Beijing 100190, china 1. research center of Computer Network and Information Security {2. Harbin Institute of Technology Harbin 150001 China2. Research Center of Information Security Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China

Identifying heavy hitters in a network traffic stream is important for a variety of network applications ranging from traffic engineering to anomaly detection such as detection of denial-of-service attacks. Existing methods generally examine newly arriving items in the stream, perform a small number of operations using a small amount of memory, and still provide guarantees on the identifying accuracy. In high-speed network monitoring, the update speed per item is extremely critical. However, so far as we know, there are no identifying algorithms which can provide constant update time (O(1)) in a weighted data stream. In this paper, we present an algorithm named Weighted Lossy Counting (WLC) which is able to identify heavy hitters in a high-speed weighted data stream with constant update time. WLC employs a novel efficient partially ordered data structure which is able to provide a fast per-item update speed while keeping the memory cost relatively low. We compare WLC with state-of-the-art algorithms for finding heavy hitters in real traffic traces. The experimental results show that WLC performs well in accuracy (recall, precision and average relative error) as other algorithms; moreover it has a much higher update speed at the cost of relatively larger memory space used. A theoretical worst-case memory bound of WLC is also derived in this paper; however, experiments with long real traffic traces show that WLC requires much less space than the theoretical bound in practice.

关键词： network traffic monitoring heavy hitter weighted data streams