检索结果-南通市图书馆

Wide/narrow azimuth acquisition footprints and their effects on seismic imaging

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2008年第4期5卷 308-313页

作者： Di Bangrang Xu Xiucang Wei Jianxin key Laboratory of CNPC Geophysical Exploration China University of Petroleum Beijing 102249 China state key Laboratory of Petroleum Resource and Prospecting China University of Petroleum Beijing 102249 China key Laboratory of Earth Prospecting and information Technology China University of Petroleum Beijing 102249 China

Acquisition footprint is a new concept to describe the seismic noise in three-dimensional seismic exploration and it is closely related to geometry and observation shuttering. At present, the study on acquisition footprints has become a hot spot. In partnership with the Dagang Oilfield, we used the channel sand body seismic physical model to study the characteristics of wide/narrow azimuth acquisition footprints and analyzed and compared the two types of footprints and their effects on target imaging. In addition, the footprints caused by data processing of the normal moveout offset （NMO） stretching aberration were discussed. These footprints are located only in the shallow or middle layer in the time slice, and possibly affect the imaging of shallow target layers, and have no influence on deep target imaging. Seismic physical modeling has its advantages in the study of acquisition footprints.

关键词： Wide/narrow azimuth geometry acquisition footprint stretching aberration time slice seismic imaging

Adaptive Image Compression based on Visual Masking Effect

在线全文

学校读者我要写书评

暂无评论

Adaptive Image Compression based on Visual Masking Effect

Evaluation of Fragility of the Economic System in Poyang Lake Ecological Economic Zone

第一届图像传播国际会议

作者： Zhigao Yang Yaohua Yi Qianqing Qin state key Laboratory of {2. Engineering in surveying {4. wuhan university 12. Luoyu Road wuhan china 4.0079 School of Printing and Packaging wuhan university 12. Luoyu Road wuhan china 4.0079

＜正＞In low bit rate coding, image compression methods aimed at minimum mean square error may lose the detail and weak information in original images, especially for smoothness areas and edges with low contrast. This is known as "smoothing" effect. Through analysis of the generation mechanism of compression distortion, we propose a visual masking effect based adaptive image compression algorithm that can reduce the "smoothing" effect in low bit rate coding. For the reason that images should be modeled as non-stationary information resources, we use blocking wavelet transform. The decomposition levels of a block are determined by texture complexity of that block. In quantization and entropy coding of wavelet coefficients, we integrate the visual masking effect. Adaptive bit rate allocation is employed to reduce distortion of weak information. Experiments by comparing with baseline JPEG2.00 show that visual quality in low bit rate coding is improved significantly, and more weak information is reserved.

关键词： visual masking effect wavelet transform image compression

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Asian Agricultural Research 2012年第8期4卷 72-76页

作者： CHENG Qiao-zhen 1 ,CHEN Xiao-ling 1. 2.,ZHU Feng-feng 1 ,ZHU Jing 1 1. School of Geography and Environment,Jiangxi Normal university,Nanchang 33002.,china 2. {2. key Laboratory of information Engineering in surveying,mapping and remote sensing,wuhan 4.002.,china

From two aspects,namely the sensitivity of regional economic system to internal and external interference,and its resilience,we establish the evaluation indicator system of fragility of the economic system in Poyang Lake Ecological Economic Zone,and evaluate the internal differences in fragility of the regional economic system,using set pair analysis method. The results show that there is a great difference in fragility of the economic system between different administrative units; the difference in resilience is the major factor responsible for difference in fragility of the economic system in various cities and counties within the region; according to the difference in fragility characteristics,we conduct classification as follows: Nanchang City is a low-sensitivity and high-resilience type; Jiujiang City is a high-sensitivity and high-resilience type; Jiujiang County,Xingzi County,Yongxiu County,Hukou County,Duchang County,Ruichang County,De'an Xian,Wuning County,Pengze County,Leping City, Dongxiang County,Fengcheng City and Gao'an City are a high-sensitivity and low-resilience type; other cities and counties are a low-sensitivity and low-resilience type.

关键词： Fragility evaluation The economic system Poyang La

Modified extremal optimization for the hard maximum satisfiability problem

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Zhejiang university-Science C(Computers and Electronics) 2011年第7期12卷 589-596页

作者： Guo-qiang ZENG 1,Yong-zai LU 2.Wei-Jie MAO 2.(1 College of Physics & Electronic information Engineering,Wenzhou university,Wenzhou 32.035,{2.) (2.state key Laboratory of Industrial Control Technology,Institute of Cyber-Systems and Control,Zhejiang university,Hangzhou 31002.,{2.) College of Physics & Electronic information Engineering Wenzhou University state key Laboratory of Industrial Control Technology Institute of Cyber-Systems and Control Zhejiang University

Based on our recent study on probability distributions for evolution in extremal optimization (EO),we propose a modified framework called EOSAT to approximate ground states of the hard maximum satisfiability (MAXSAT) problem,a generalized version of the satisfiability (SAT) *** basic idea behind EOSAT is to generalize the evolutionary probability distribution in the Bose-Einstein-EO (BE-EO) algorithm,competing with other popular algorithms such as simulated annealing and *** results on the hard MAXSAT instances from SATLIB show that the modified algorithms are superior to the original BE-EO algorithm.

关键词： Extremal optimization (EO) Evolution Probability distributions Maximum satisfiability (MAXSAT) problem

Perceptual video hashing robust against geometric distortions

在线全文

学校读者我要写书评

暂无评论

Science china(information Sciences) 2012年第7期55卷 1520-1527页

作者： XIANG ShiJun 1,4.,YANG JianQuan 2.& HUANG JiWu 3 1 School of information Science and Technology,Jinan university,Guangzhou 510632.{2. 2.Shenzhen Institutes of Advanced Technology,Chinese Academy of Sciences,Shenzhen 518055,{2. 3 School of information Science and Technology,Sun Yat-sen university,Guangzhou 5102.5,{2. 4.state key Laboratory of information Security,Institute of Software,Chinese Academy of Sciences,Beijing 10004.,{2. 1. School of information Science and Technology Jinan University Guangzhou 510632 China4. State Key Laboratory of Information Security Institute of Software Chinese Academy of Sciences Beijing 100049 China2. Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 China3. School of Information Science and Technology Sun Yat-sen University Guangzhou 510275 China

In this paper,we propose a robust perceptual hashing algorithm by using video luminance histogram in *** underlying robustness principles are based on three main aspects:1) Since the histogram is independent of position of a pixel,the algorithm is resistant to geometric deformations; 2. the hash is extracted from the spatial Gaussian-filtering low-frequency component for those common video processing operations such as noise corruption,low-pass filtering,lossy compression,etc.; 3) a temporal Gaussian-filtering operation is designed so that the hash is resistant to temporal desynchronization operations,such as frame rate change and *** a result,the hash function is robust to common geometric distortions and video processing *** results show that the proposed hashing strategy can provide satisfactory robustness and uniqueness.

关键词： video hashing geometric distortion histogram Gaussian filtering

Development of silicon-based microelectrode array

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8期52卷 2391-2395页

作者： LIN JianHui1,2.3, WU XiaoMing1,2.3,4. HUANG PengSheng1,2. FENG Lei5, REN TianLing1,2.& LIU LiTian1,2.1 Institute of Microelectronics, Tsinghua university, Beijing 100084. china 2.Tsinghua National Laboratory for {2. Science and Technology, Beijing 100084. china 3 Yangtze Delta Region Institute of Tsinghua university, Jiaxing 314.50, china 4.state key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai 2.0050 china 5 Department of Biomedical Engineering, Tsinghua university, Beijing 100084. china 1. Institute of Microelectronics Tsinghua University Beijing 100084 China 2. Tsinghua National Laboratory for information Science and Technology Beijing 100084 China 3. Yangtze Delta Region Institute of Tsinghua university Jiaxing 314050 China 4. state key Laboratory of Transducer Technology Chinese Academy of Sciences Shanghai 200050 China 5. Department of Biomedical Engineering Tsinghua University Beijing 100084 China

This paper introduces in details a kind of silicon-based microelectrode array. MEMS (micro-electromechanical system) technology is used in the fabrication of the microelectrode array, which is designed to perform signal recording and electrical stimulation for nerves in neural engineering. A simple fabrication process is developed. An improved model of microelectrodes is brought forward and successfully validated by the excellent match between circuit simulations and electrical measurements, including both magnitude and phase of microelectrode impedance. Compared with the simple one that is usually used, the improved model is believed to be an advance and more accurate. This modeling helps to improve the design of microelectrodes and understand the behavior of interface between electrode and cell. Furthermore, the microelectrode is proved to be a feasible tool for researches in neural engineering by successfully recording neural activities of sciatic nerve of a bullfrog.

关键词： microelectrode array MEMS neural engineering

基于Internet的大规模城市建筑三维场景可视化研究

在线全文

学校读者我要写书评

暂无评论

系统仿真学报 2009年第10期21卷 2965-2970,2976页

作者：何正伟吴华意陈静武汉大学测绘遥感信息工程国家重点实验室武汉430072

城市场景的构建是数字城市的基础。在互联网上实现大规模城市建筑物场景实时绘制,受到带宽瓶颈及三维可视化海量数据吞吐量的限制。通过分析其特点后,设计了适合网络传输的三维模型数据结构和充分考虑可视化效率的系统服务架构,提出了... 详细信息

城市场景的构建是数字城市的基础。在互联网上实现大规模城市建筑物场景实时绘制,受到带宽瓶颈及三维可视化海量数据吞吐量的限制。通过分析其特点后,设计了适合网络传输的三维模型数据结构和充分考虑可视化效率的系统服务架构,提出了完全层次四叉树与集合的混合结构的数据组织模型,分析和论证了构建模型依据和方法。然后,讨论了建筑物场景的调度策略和方案。开发了虚拟地球平台GeoGlobe并运用于两个应用系统。实验和应用结果表明,能在普通PC机上实现大规模建筑物场景的流畅调度、实时浏览,可视化效果和用户体验好。

关键词：网络GIS 城市建筑物模型海量数据数据组织模型实时三维浏览

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 {4. key Laboratory of Networking and Switching Technology,Beijing {2. of Posts and Telecommunications,Beijing 100876,china 2.state key Laboratory of Wireless Mobile Communications,china Academy of Telecommunications Technology,Beijing 100191,china 1. state key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China2. State Key Laboratory of Wireless Mobile Communications China Academy of Telecommunications Technology Beijing 100191 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

Parallel algorithm for real-time contouring from grid DEM on modern GPUs

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 33-37页

作者： CHEN Zhuo,SHEN Lei,ZHAO YanQing & YANG ChongJun state key Laboratory of {2. sensing Science,Jointly Sponsored by the Institute of {2. sensing Applications of Chinese Academy of Sciences and Beijing Normal university,Beijing 100101,china 1. state key Laboratory of {2. sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China

A real-time algorithm for constructing contour maps from grid DEM data is *** runs completely within the programmable 3D visualization *** interpolation is paralleled by rasterizer units in the graphics card,and contour line extraction is paralleled by pixel *** each frame of the rendering,we first make an elevation gradient map out of original terrain vertex data,then figure out the final contour lines with image-space processing,and directly blend the results on the original scene to obtain a final scene with contour map using *** implement this method in our global 3D-digitalearth system with Direct3D?9.0c API and tested on some consumer level PC *** arbitrary scene with certain LOD level,the process takes less than 10 ms,giving topologically correct,anti-aliased contour lines.

关键词： contour map contour lines paralleled computing 3D terrain GPU digital earth