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Improving the accuracy of image-based forest fire recognition and spatial positioning

Science china(Technological sciences) 2010年第S1期53卷 184-190页

作者： JIANG LiLi 1,QI QingWen 1,ZHANG An 1,GUO ChaoHui 2 & CHENG Xi 1,3 1 Institute of Geographical sciences and Natural Resources Research,chinese academy of sciences,beijing 100101,china 2 china Center for Resources Satellite Data and Applications,beijing 100094,china 3graduate university of chinese academy of sciences,beijing 100049,china Institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences Beijing China china Center for Resources Satellite Data and Applications Beijing China graduate university of chinese academy of sciences Beijing China

Forest fires are frequent natural *** is necessary to explore advanced means to monitor,recognize and locate forest fires so as to establish a scientific system for the early detection,real-time positioning and quick fighting of forest *** paper mainly expounds methods and algorithms for improving accuracy and removing uncertainty in image-based forest fire recognition and spatial ***,we discuss a method of forest fire recognition in visible-light *** are four aspects to improve accuracy and remove uncertainty in fire recognition:(1)eliminating factors of interference such as road and sky with high brightness,red leaves,other colored objects and objects that are lit up at night,(2)excluding imaging for specific periods and azimuth angles for which interference phenomena repeatedly occur,(3)improving the thresholding method for determining the flame border in image processing by adjusting the threshold to the season,weather and region,and (4)integrating the visible-light image method with infrared image ***,we examine infrared-image-based methods and approaches of improving the accuracy of forest fire recognition by combining the spectrum threshold with an object feature value such as the normalized difference vegetation index and excluding factors of disturbance such as interference signals,extreme weather and high-temperature ***,a method of visible analysis to enhance the accuracy of forest fire positioning is examined and realized;the method includes decreasing the visual angle,selecting central points,selecting the largest spots,and judging the selection of fire spots according to the central *** studies are examined and the results are found to be satisfactory.

关键词： forest fire monitoring spatial positioning accuracy improvement

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Birthrates and delay times of Type Ia supernovae

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Science china(Physics,Mechanics & Astronomy) 2010年第3期53卷 586-590页

作者： WANG Bo1,2,3, LIU ZhengWei1,2,3, HAN YunKun1,2,3, LEI ZhenXin1,2,3, LUO YangPing1,2,3 & HAN ZhanWen1,2 1National Astronomical Observatories/Yunnan Observatory, chinese academy of sciences, Kunming 650011, china 2Key Laboratory for the Structure and Evolution of Celestial Objects, chinese academy of sciences, Kunming 650011, china 3graduate university of chinese academy of sciences, beijing 100049, china chinese academy of sciences National Astronomical Observatories/Yunnan Observatory Kunming China (GRID:grid.9227.e) (ISNI:***) chinese academy of sciences Key Laboratory for the Structure and Evolution of Celestial Objects Kunming China (GRID:grid.9227.e) (ISNI:***) graduate university of chinese academy of sciences Beijing China (GRID:grid.458514.9) chinese academy of sciences National Astronomical Observatories/Yunnan Observatory Kunming China (GRID:grid.9227.e) (ISNI:***) chinese academy of sciences Key Laboratory for the Structure and Evolution of Celestial Objects Kunming China (GRID:grid.9227.e) (ISNI:***)

Type Ia supernovae (SNe Ia) play an important role in diverse areas of astrophysics, from the chemical evolution of galaxies to observational cosmology. However, the nature of the progenitors of SNe Ia is still unclear. In this paper, according to a detailed binary population synthesis study, we obtained SN Ia birthrates and delay times from different progenitor models, and compared them with observations. We find that the Galactic SN Ia birthrate from the double-degenerate (DD) model is close to those inferred from observations, while the birthrate from the single-degenerate (SD) model accounts for only about 1/2-2/3 of the observations. If a single starburst is assumed, the distribution of the delay times of SNe Ia from the SD model is a weak bimodality, where the WD + He channel contributes to the SNe Ia with delay times shorter than 100 Myr, and the WD + MS and WD + RG channels to those with age longer than 1 Gyr.

关键词： binaries: close stars: evolution supernovae: general white dwarfs

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On designated-weight Boolean functions with highest algebraic immunity

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Science china Mathematics 2010年第11期53卷 2847-2854页

作者： LIU MeiCheng1,3, DU YuSong2, PEI DingYi2 & LIN DongDai1 1The State Key Laboratory of Information Security, Institute of Software of chinese academy of sciences, beijing 100190, china 2College of Mathematics and Information sciences, Guangzhou university, Guangzhou 510006, china 3graduate university of chinese academy of sciences, beijing 100049, china The State Key Laboratory of Information Security Institute of Software of Chinese Academy of Sciences College of Mathematics and Information sciences Guangzhou University graduate university of chinese academy of sciences

Algebraic immunity has been considered as one of cryptographically significant properties for Boolean functions. In this paper, we study ∑d-1 i=0 (ni)-weight Boolean functions with algebraic immunity achiev-ing the minimum of d and n - d + 1, which is highest for the functions. We present a simpler sufficient and necessary condition for these functions to achieve highest algebraic immunity. In addition, we prove that their algebraic degrees are not less than the maximum of d and n - d + 1, and for d = n1 +2 their nonlinearities equalthe minimum of ∑d-1 i=0 (ni) and ∑ d-1 i=0 (ni). Lastly, we identify two classes of such functions, one having algebraic degree of n or n-1.

关键词： cryptography Boolean function algebraic immunity algebraic degree nonlinearity

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Information content security on the Internet:the control model and its evaluation

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Science china(Information sciences) 2010年第1期53卷 30-49页

作者： FANG BinXing1, GUO YunChuan2,3 & ZHOU Yuan4 1School of Computer, beijing university of Posts and Telecommunications, beijing 100029, china 2Institute of Computing Technology, chinese academy of sciences, beijing 100190, china 3graduate university of chinese academy of sciences, beijing 100049, china 4National Computer Network Emergency Response Technical Team/Coordination Center of china, beijing 100029, china School of Computer Beijing University of Posts and Telecommunications Institute of Computing Technology Chinese Academy of Sciences graduate university of chinese academy of sciences National Computer Network Emergency Response Technical Team/Coordin

Flooding of harmful information on the Internet seriously endangers the physiological and mental health of teenagers. Due to the user-friendliness of the Internet as well as the difficulty in the authentication for the access of specific categories of information, curbing the transmission of harmful information, i.e., assuring the information content security (ICS), has become a reasonable yet challenging alternative. At present, there is an urgent need to develop a systematic model that can effectively carry out the curbing. In fact, curbing the transmission of harmful information by way of filtering can be modeled by access control. In the paper, based on the three core-elements of communication, namely, "Who communicates with whom", "How do they communicate" and "What is the content of communication", we propose a control model, called ICCON. Unlike the existing access control, the reference monitor (RM) of our model is placed in the transmission channel, and moreover, an evaluation frame is proposed, through which the effectiveness of the RM in controlling information transmission on the Internet can be quantitatively evaluated.

关键词： content security access control quantitative evaluation

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Multi-channel SAR imaging based on distributed compressive sensing

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Science china(Information sciences) 2012年第2期55卷 245-259页

作者： LIN YueGuan1,2,3,ZHANG BingChen1,2,JIANG Hai1,2,3,HONG Wen1,2 & WU YiRong1,2 1National Key Laboratory of Science and Technology on Microwave Imaging,beijing 100190,china 2Institute of Electronics,chinese academy of sciences,beijing 100190,china 3graduate university of chinese academy of sciences,beijing 100049,china National Key Laboratory of Science and Technology on Microwave Imaging Institute of Electronics Chinese Academy of Sciences graduate university of chinese academy of sciences

The rapid development of compressive sensing(CS)shows that it is possible to recover a sparse signal from very limited *** aperture radar(SAR)imaging based on CS can reconstruct the target scene with a reduced number of collected samples by solving an optimization *** multi-channel SAR imaging based on CS,each channel requires sufficient samples for separate imaging and the total number of samples could still be *** propose an imaging algorithm based on distributed compressive sensing(DCS)that reconstructs scenes jointly under multiple ***-channel SAR imaging based on DCS not only exploits the sparsity of the target scene,but also exploits the correlation among *** requires significantly fewer samples than multi-channel SAR imaging based on *** multiple channels offer different sampling rates,DCS joint processing can reconstruct target scenes with a much more flexible allocation of the number of measurements offered by each channel than that used in separate CS processing.

关键词： synthetic aperture radar multi-channel synthetic aperture radar compressive sensing distributed compressive sensing

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Simulation of freezing and melting of soil on the northeast Tibetan Plateau

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chinese Science Bulletin 2011年第20期56卷 2145-2155页

作者： XIA Kun 1,2,3,LUO Yong 2,4,5 & LI WeiPing 2 1 Institute of Atmospheric Physics,chinese academy of sciences,beijing 100029,china 2National Climate Center,china Meteorological Administration,beijing 100081,china 3graduate university of chinese academy of sciences,beijing 100049,china 4 Center for Earth System Science,Tsinghua university,beijing 100084,china 5Key Laboratory of Earth System Numerical Simulation,Ministry of Education,beijing 100084,china Institute of Atmospheric Physics Chinese Academy of Sciences National Climate Center China Meteorological Administration graduate university of chinese academy of sciences Center for Earth System Science Tsinghua University Key Laboratory of Earth

Using observational data spanning the period from February to December 2009 and recorded at the Suli station in Qinghai Province,the land-surface model CLM3.0 was employed to simulate the freezing and melting of *** results indicate that the simulated soil temperature is higher than the observed soil temperature and the ultimate thawing date is earlier than the observed date during the melting *** the freezing period,the simulated soil temperature is lower than the observed soil temperature and the ultimate freezing of the deep soil is earlier than that ***,the simulation of freezing is better than that of melting,and the simulation of a shallow layer is better than that of a deeper *** the original CLM3.0,it is assumed that frozen soil begins to melt when the soil temperature exceeds 0C,which is inconsistent with *** critical freeze-thaw temperature was calculated according to thermodynamics equations and the freeze-thaw condition was *** this work,the melting rate for frozen soil was reduced using the modified scheme,and the simulated soil temperature was lowered. Meanwhile,the refreezing of soil during the melting season was well simulated and more closely matched ***,it was found that the rates of melting and freezing differ,with the former being slower than the latter,but refreezing during the melting season is rather quick.

关键词：土壤温度冻结期青藏高原东北部模拟融化观测数据热力学方程表面模型

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Use-wear evidence confirms the earliest hafted chipped-stone adzes of Upper Palaeolithic in northern china

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chinese Science Bulletin 2010年第3期55卷 268-275页

作者： ZHANG XiaoLing1,2,3, SHEN Chen1,2,4 GAO Xing1,2 CHEN FuYou1,2 & WANG ChunXue1,2,3 1Institute of Vertebrate Paleontology and Paleoanthropology, chinese academy of sciences, beijing 100044, china 2Laboratory of Human Evolution and Archaeometry, chinese academy of sciences, beijing 100044, china 3graduate university of chinese academy of sciences, beijing 100049, china 4The Royal Ontario Museum, Toronto M5S 2C6, Canada Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing 100044 China Laboratory of Human Evolution and Archaeometry Chinese Academy of Sciences Beijing 100044 China graduate university of chinese academy of sciences Beijing 100049 China Royal Ontario Museum Toronto M5S 2C6 Canada

Chipped-stone "adze-shaped objects" (ASOs) were identified from a few Upper Palaeolithic sites in northern china. Its morpho- logical form resembles to ground-stone type-specific adze, but the function of the ASO has never been assessed. The objective of this study is to investigate the use function of this particular tool type recovered from the Hutouliang site in the Nihewan Basin of northern china. In this study, the lithic use-wear analysis is applied to examining microscopically edge-damages and sur- face-rounding of the tools in order to assess how they were employed. The result suggests that the ASO might have been used as woodworking tools with a hafted shaft, providing evidence for the appearance of the earliest hafted chipped-stone adzes prior to 10000 years ago in northern china. This study also demonstrates that the use-wear technique is an innovated and effective analytic appraoch to the study of stone tool functions that has been conventionally treated by typo-technological analyses. Stone tool use-patterns revealed by use-wear evidence would shed new insights on prehistoric adaptive strategies of modern human in northern china.

关键词：旧石器时代晚期中国北方磨损证据石材加工工具木工工具中国网站技术分析

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Effects of Temperature and Water Saturation on CO_2 Production and Nitrogen Mineralization in Alpine Wetland Soils

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Pedosphere 2009年第1期19卷 71-77页

作者： GAO Jun-Qin OUYANG Hua XU Xing-Liang ZHOU Cai-Ping ZHANG Feng beijing Forestry university Beijing 100083 （China） Institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 （China） graduate university of the chinese academy of sciences Beijing 100049 （China）

Relationships between carbon (C) production and nitrogen (N) mineralization were investigated in two alpine wetland soils of the Tibetan Plateau using laboratory incubation under different temperatures (5, 15, 25, and 35 ℃) and water saturation (noninundation and inundation). A significant positive relationship was found between CO2 production and N mineralization under increasing temperatures from 5 to 35 ℃ with the same water saturation condition in the marsh soil (r2 > 0.49, P 0.38, P 35 ℃, in the marsh soil (r2 > 0.70, P 0.61, P 3). In conclusion, temperatures and water saturation could regulate the relationship between CO2 production and net N mineralization in the Tibetan alpine marsh and peat soils.

关键词： CO2 production N mineralization temperature water saturation wetland

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Potential of Industrial Byproducts in Ameliorating Acidity and Aluminum Toxicity of Soils Under Tea Plantation

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Pedosphere 2010年第5期20卷 645-654页

作者： LI Jiu-Yu WANG Ning XU Ren-Kou D. TIWARI State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 (China) Department of Chemistry Mizoram University Tanhril Campus Aizawl 796009 (India) graduate university of the chinese academy of sciences Beijing 100049 (China)

It is imperative to choose some low cost, available and effective ameliorants to correct soil acidity in southern china for sustainable agriculture. The present investigation dealt with the possible role of industrial byproducts, i.e., coal fly ash （CFA）, alkaline slag （AS）, red mud （RM） and phosphogypsum （PG） in correcting acidity and aluminum （Al） toxicity of soils under tea plantation using an indoor incubation experiment. Results indicated that CFA, AS and RM increased soil pH, while PG decreased the pHs of an Ultisol and an Alfisol. The increment of soil pH followed the order of RM 〉 AS 〉 CFA. All the industrial byproducts invariably decreased exchangeable Al and hence increased exchangeable Ca, Mg, K and Na and effective cation exchange capacity. RM, AS and lime decreased total soluble Al, exchangeable Al and organically bound Al. Formation and retention of hydroxyl-Al polymers were the principal mechanism through which Al phytotoxicity was alleviated by application of these amendments. In addition, the heavy metal contents in the four industrial byproducts constituted a limited environmental hazard in a short time at the rates normally used in agriculture. Therefore, the short-term use of the byproducts, especially AS and RM, as amendments for soil acidity and AI toxicity in acid soils may be a potential alternative to the traditional use of mined gypsum and lime.

关键词： acid soil alkaline slag amelioration coal fly ash red mud

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Distribution of Soil Organic Carbon Fractions Along the Altitudinal Gradient in Changbai Mountain,china

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Pedosphere 2011年第5期21卷 615-620页

作者： ZHANG Min ZHANG Xiao-Ke LIANG Wen-Ju JIANG Yong DAI Guan-Hua WANG Xu-Gao HAN Shi-Jie State Key Laboratory of Forest and Soil Ecology Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110164 (China) Vegetable Research Institute Liaoning Academy of Agricultural Sciences Shenyang 110161 (China) graduate university of chinese academy of sciences Beijing 100049 (China)

Understanding the responses of soil organic carbon(SOC) fractions to altitudinal gradient variation is important for understanding changes in the carbon balance of forest *** our study the SOC and its fractions of readily oxidizable carbon(ROC),water-soluble carbon(WSC) and microbial biomass carbon(MBC) in the soil organic and mineral horizons were investigated for four typical forest types,including mixed coniferous broad-leaved forest(MCB),dark coniferous spruce-fir forest(DCSF),dark coniferous spruce forest(DCS),and Ermans birch forest(EB),along an altitudinal gradient in the Changbai Mountain Nature Reserve in Northeast *** results showed that there was no obvious altitudinal pattern in the *** variation trends of SOC with altitude were observed between the organic and mineral *** differences in the contents of SOC,WSC,MBC and ROC were found among the four forest types and between *** contents of ROC in the mineral horizon,WSC in the organic horizon and MBC in both horizons in the MCB and EB forests were significantly greater than those in either DCSF or DCS *** proportion of soil WSC to SOC was the lowest among the three main *** contents of WSC,MBC and ROC were significantly correlated(P < 0.05) with SOC *** can be concluded that vegetation types and climate were crucial factors in regulating the distribution of soil organic carbon fractions in Changbai Mountain.

关键词： active carbon fractions altitude forest ecosystem Northeast china vegetation type

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