检索结果-南通市图书馆

Digital forestry research in china

在线全文

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2006年第Z1期49卷 1-8页

作者： TANG Shouzheng, TANG Una, Guofan Shao & DAI Limin Research institute of Resource information Techniques, chinese academy of Forestry, beijing 100091, china institute of Applied Ecology, chinese academy of sciences, Shenyang 110016, china Departmet of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA Graduate University, chinese academy of sciences, beijing 100101, china Research institute of Resource information Techniques Chinese Academy of Forestry Beijing China institute of Applied Ecology Chinese Academy of Sciences Shenyang China Graduate University Chinese Academy of Sciences Beijing China Department of Forestry and Natural Resources Purdue University West Lafayette USA

Digital Forestry as a concept was developed after the Digital Earth program. The chinese scientists were not only among the pioneers who first proposed the concept of Digital Forestry, but also contributed a lot to the development of Digital Forestry. Digital Forestry is a digital framework to maintain forest planting, management, using, and protect. The synergetic use of computationally-intensive quantitative methods together with information technologies is the most important foundation for the development of Digital Forestry. Under this situation, the experience of Digital Forestry development in china is relatively rich. A number of academicians, scholars, and professional administrators were involved in discussing the Digital Forestry Construction Scheme. The Project of Digital Forestry Practicability approved by the state Forestry Administration is a major instance in developing Digital Forestry standard and key techniques. By introducing a case study of Digital Forestry, this paper reviews the concept of Digital Forestry, the way turning traditional forestry into Digital Forestry, and the future development of Digital Forestry.

关键词： Digital Forest, Digital Earth, Digital Forestry standard, Digital Forestry techniques.

A unified dynamic model for locomotion and manipulation of a snake-like robot based on differential geometry

在线全文

学校读者我要写书评

暂无评论

Science china(information sciences) 2011年第2期54卷 318-333页

作者： WANG ZhiFeng1,3, MA ShuGen1,2, LI Bin1 & WANG YueChao1 1state key laboratory of Robotics, Shenyang institute of Automation, chinese academy of sciences, Shenyang 110016, china 2Department of Robotics, Ritsumeikan University, Shiga-ken 525-8577, Japan 3Graduate University of chinese academy of sciences, beijing 100039, china state key laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Shenyang China Graduate University of chinese academy of sciences Beijing China Department of Robotics Ritsumeikan University Shiga-ken Japan

A snake-like robot, whose body is a seried-wound articulated mechanism, can move in various environments. In addition, when one end is fixed on a base, the robot can manipulate objects. A method of dynamic modeling for locomotion and manipulation of the snake-like robot is developed in order to unify the dynamic equations of two states. The transformation from locomotion to manipulation is a mechanism reconfiguration, that is, the robot in locomotion has not a fixed base, but it in manipulation has one. First, a virtual structure method unifies the two states in mechanism (e.g., an embedding in the configuration space); second, the product-of-exponentials formula describes the kinematics; third, the dynamics of locomotion and manipulation are established in a Riemannian manifold; finally, based on the analysis of the dynamic model, the dynamics of manipulation can be directly degenerated from those of locomotion, and this degeneration relation is proved through using the Gauss equations. In the differential geometry formulation, this method realizes the unification of the dynamics of locomotion and manipulation. According to a geometrical point of view, the unified dynamic model for locomotion and manipulation is considered as a submanifold problem endowed with geometric meaning. In addition, the unified model offers an insight into the dynamics of the snake-like robot beyond the dynamic model separately established for locomotion or manipulation.

关键词： snake-like robot dynamics unified model differential geometry locomotion manipulation

Origin Distribution Patterns and Floating Population Modeling:Yiwu City as a Destination

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

chinese Geographical Science 2012年第3期22卷 367-380页

作者： LI Hongsheng WANG Yingjie HAN Jiafu state key Laboratoty of Resources and Environmental information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

Existing quantitative migration studies are mainly at the inter-region or inter-province level for lacking of detailed geo-referenced migration ***,few of them integrate explorative spatial data analysis and spatial regression model into migration *** on aggregated registered floating population data from 2005 to 2008,the phenomena that population floating to Yiwu City in Zhejiang Province is analyzed at the provincial and county *** spatial layout of Yiwu's pull forces is proved as a V-shaped pattern excluding Sichuan Province based on map visualization *** the migration ratio in 2007 as an explanatory variable,two models are compared using ordinary least square,spatial error model and spatial lag model methods for county-level data in Jiangxi and Anhui *** model with migration stock provides an improved fitting over the model without migration stock according to the model fitting *** floating population flocking into Yiwu City from Jiangxi is determined mostly by migration stock while the determinant factors are migration stock and distance to Yiwu City for *** distance-decay effect is true for migration flow from Anhui to Yiwu City while the distance rule is not confirmed in Jiangxi with the best fitting *** correlation between per capita net income of rural labor forces and migration ratio is not significant in Jiangxi and significant but at the 0.1 level only in *** analysis shows that the distance,income and man-land ratio are important factors to explain population floating at earlier ***,as the dynamic population floating process evolves,the determinant factor would be migration stock.

关键词： floating population origin distribution visualization spatial regression model Yiwu City GIS

Studies and advances on joint source-channel encoding/decoding techniques in flow media communications

在线全文

学校读者我要写书评

暂无评论

Science china(information sciences) 2010年第1期53卷 1-17页

作者： TU GuoFang1, LIU JianJun1, ZHANG Can1,2, GAO ShaoShuai3 & LI ShiDong4 1School of information Science and Engineering, Graduate University of chinese academy of sciences, beijing 100049, china 2state key laboratory of information security, Graduate University of chinese academy of sciences, beijing 100049, china 3National institute of Standards and Technology, Gaithersburg, MD 20899, USA, 4Department of Mathematics, San Francisco state University, San Francisco, CA 94132, USA School of information Science and Engineering Graduate University of Chinese Academy of Sciences Beijing China state key laboratory of information security Graduate University of Chinese Academy of Sciences Beijing China National institute of Standards and Technology Gaithersburg USA Department of Mathematics San Francisco State University San Francisco USA

Joint source-channel coding/decoding (JSCC/JSCD) techniques in flow media communications have become a state-of-the-art and one of the challenging research subjects in the spatial communication area. They have great application prospective and deep impact in various manned space flights, satellite missions, mobile radio communications and deep-space explorations. In the last few years, there have been influential achievements in JSCC/JSCD studies. This paper aims at an introduction to the basic principles of joint source-channel optimal design. A general summarization and classification for various existing JSCC/JSCD methods is addressed. Also presented is a JSCD scheme based on variable-length coding, capable of providing reliable resolutions for flow media data transmission in spatial communications.

关键词： joint source-channel coding/decoding rate allocation variable-length coding/decoding iterative decoding

Optimization of mathematical models for thematic maps

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) 2010年第S1期53卷 15-24页

作者： QI QingWen1,ZHANG An1,JIANG LiLi1,ZOU XiuPing2,XU Li3 & CHENG Xi1,4 1 institute of Geographical sciences and Natural Resources Research,chinese academy of sciences,beijing 100101,china 2 institute of Policy and Management,chinese academy of sciences,beijing 100080,china 3 Taishan University,Taian 271021,china 4 Graduate University of chinese academy of sciences,beijing 100049,china institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences Beijing China institute of Policy and Management Chinese Academy of Sciences Beijing China Taishan University Taian China Graduate University of chinese academy of sciences Beijing China

The thematic map is a major class of maps designed to demonstrate particular features or concepts,functioning as an indispensable tool in geographical *** process of thematic mapping is one into which geographical research goes deeply and *** key activity and course of thematic map production is the use of mathematical models to create thematic data ***,the selection and optimization of mathematical models is in the forefront of thematic map *** theoretical foundations,mechanisms and methods of mathematical model optimization are expounded in this paper,including two approaches,the phase by phase mode and the multi-aim scheme balance *** studies in eco-environment mapping and emergency mapping are described and analyzed,with a hierarchical analysis method being used in the model optimization for eco-environment fragility and sensitivity assessment mapping in Beibuwan (Guangxi) District,the dynamic system (DS) method being used in the model optimization for ecological security adjustment mapping in Xishuang Banna,Yunnan province,and the multi-phase mode being used in the models for forest fire and infectious diseases mapping.

关键词： thematic map mathematic model optimization

^(137)Cs Redistribution in Thin Stony Soil of a Carbonate Rock Slope in Southwest china

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2011年第1期21卷 37-45页

作者： LI Hao ZHANG Xin-Bao WANG Kc-Lin WEN An-Bang institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 (China) Graduate University Chinese Academy of Sciences Beijing 100049 (China) state key laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 (China) institute of Subtropical Agriculture Chinese Academy of Sciences Changsha 410125 (China)

The fallout radionuclide cesium-137(137 Cs) has been widely employed as a tracer for assessment of soil loss from thick uniform soils;however,few studies have been conducted on thin stony soils on slopes underlain by carbonate rocks which are widely distributed in karst *** derived from 137 Cs measurement of soil samples collected along a carbonate rock slope with thin stony soil where neither soil erosion nor deposition occurred was used to investigate the characteristics of 137 Cs redistribution in a karst area of Southwest *** results indicated that the 137 Cs inventories of the surface soil on the slope studied were much lower than that of the local 137 Cs reference inventory and the 137 Cs activities were much higher than those on slopes with thick uniform *** spatial distribution of 137 Cs inventories was characterized by considerable *** high 137 Cs depletion in the stony soil of the slope studied was mainly because a considerable proportion of the fallout input of 137 Cs could be lost with runoff and the dissolution of carbonate particles in the soil promoted the loss of 137 *** demonstrated that the rates of soil loss could not be estimated from the degree of depletion of the 137 Cs inventory relative to the local reference inventory for the thin stony soil of the rocky slope underlain by carbonate rocks in the study area in the way that has been widely used in areas with thick uniform soils.

关键词： carbonate dissolution, ^137Cs fallout, ^137Cs inventory karst area runoff

Practical conditions of signal space alignment for generalized MIMO Y channel

在线全文

学校读者我要写书评

暂无评论

Science china(information sciences) 2012年第10期55卷 2171-2182页

作者： SHE JiaJu 1,2,CHEN ShanZhi 1,2,HU Bo 1,WANG YingMin 2 & SU Xin 2 1 state key laboratory of Networking and Switching Technology,beijing University of Posts and Telecommunications,beijing 100876,china 2 state key laboratory of Wireless Mobile Communications,china academy of Telecommunications Technology,beijing 100191,china state key laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing China state key laboratory of Wireless Mobile Communications China Academy of Telecommunications Technology Beijing China

This paper proposes a generalization for applications of signal space alignment(SSA) in a generalized multiple input multiple output(MIMO) Y channel with K(K 2) nodes and an intermediate *** on that generalization,a method is introduced to determine the practical conditions for *** first study the generalized MIMO Y channel model with general signal demands;then,the degrees of freedom(DoF) achieved are given and are proved using *** SSA could decrease the number of antennas at the relay,it places new restrictions on the numbers of antennas at the *** then introduce a method to compare the models with and without SSA network coding(SSA-NC),mainly from the perspective of the total number of antennas *** results show that if each node must be able to exchange signals with all others,the model with SSA will definitely use more antennas to supply the same DoF,when K > *** it is not necessary for every node to exchange signals with all others,the comparison can still be made by using the method introduced *** a result,the conditions under which SSA-NC is needed are presented.

关键词： Signal space alignment MIMO Y channel degrees of freedom number of antennas

Tn5-mutagenesis and identification of atr operon and trpE gene responsible for indole-3-acetic acid synthesis in Azospirillum brasilense Yu62

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 2006年第4期16卷 366-372页

作者： XIE Baoen and CHEN Sanfeng state key laboratory for Agrobiotechnology, College of Biological sciences, china Agricultural University, beijing 100094, china state key laboratory for Agrobiotechnology College of Biological Sciences China Agricultural University Beijing 100094 China

To bring more information about synthesis of indole-3-acetic acid (IAA) from Azospirillum brasilense, a Tn5-insertion library of A. brasilense Yu62 was constructed and subjected to screening for IAA producing mutants. Two mutants with decreased IAA levels, named as A3 and A24, were isolated. The sequence analysis of loci tagged showed that the Tn5-1063a was located in the atrA gene encoding GntR family transcriptional regulator and trpE gene encoding component I of anthranilate synthase respectively. At the same time. atrB encoding phosphotransferase and atrC encoding aminotransferase were cloned downstream the atrA gene and atrA, atrB and atrC were clustered in an operon. Mutagenesis and complementation studies showed that atrA and atrC were involved in IAA synthesis. IAA levels of trpE mutant and wild-type strain could be improved by adding anthranilate into the medium.

关键词： indole-3-acetic acid (IAA) IAA mutants Azospirillum brasilense atrABC cluster trpE Tn5 transposon.

Attention and available long-term memory in an activation-based model

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(Life sciences) 2010年第6期53卷 743-752页

作者： LIU ZhaoMin1,GUO ChunYan2,3 & LUO Liang4 1 School of Sociology,china University of Political Science and Law,beijing 102249,china 2 beijing key laboratory of Learning and Cognition,Department of Psychology,Capital Normal University,beijing 100048,china 3 key laboratory of Mental Health,chinese academy of sciences,beijing 100101,china 4 state key laboratory of Cognitive Neuroscience and Learning,beijing Normal University,beijing 100875,china School of Sociology China University of Political Science and Law Beijing China beijing key laboratory of Learning and Cognition Department of Psychology Capital Normal University Beijing China key laboratory of Mental Health Chinese Academy of Sciences Beijing China state key laboratory of Cognitive Neuroscience and Learning Beijing Normal University Beijing China

The influence of attention on memorizing related items and on available long-term memory (ALTM) was explored,showing that N400 of no-memory items was more negative than that of the memory *** results of the category comparison task indicated that information processing under attention-driven in WM determined the availability of related long-term memory,i.e.,specific content,which was formerly concerned or ignored,yielding different indirect semantic priming *** indicate that the orientation of conceptual attention leads the related representations of LTM to diverse activation patterns,supporting the activation-based model.

关键词： activation-based model attention available long-term memory event-related potentials