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Studies on a Novel Characteristic Atom-pair Holographic Code Applied to Quantitative Structure-chromatographic Retention Relationship of Organic Compounds 被引量:1
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作者 ZHOU Peng TIAN Fei-Fei +1 位作者 WANG Jiao-Na LI Zhi-Liang 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2006年第11期1337-1342,共6页
6 Atomic fragment types of organic compound have been defined, and the multilevel atom-pair frequency matrix has been constructed according to the occurrence number in pairs of atomic fragments with different bond len... 6 Atomic fragment types of organic compound have been defined, and the multilevel atom-pair frequency matrix has been constructed according to the occurrence number in pairs of atomic fragments with different bond lengths in the molecule. On the basis of them, a novel molecular coding technique: characteristic atom-pair holographic code (CAHC), is obtained. To some extent, this method exhibits a large number of benefits at the same time. For example, it can calculate 2D molecular topological descriptor easily, operate without difficulty and possess definite physicochemical meaning of 3D molecular structural characterization methods, and may fetch the complicated information of molecule, etc. Therefore, it is appropriate for the study on quantitative structure-property/activity relationship (QSPR/QSAR) of medicines and biological molecules. We attempt in this paper to utilize the method of CAHC to the quantitative prediction of reversed-phase liquid chromatogram (RPLC) retention data of 33 purine derivatives and 24 steroids. The fitting multiple correlation coefficient R2, cross-validated multiple correlation coefficient Q2 and predicted ability Q^2 pred over test set's samples of obtained partial least-square (PLS) regression model are respectively 0.990, 0.893 and 0.977, 0.897, 0.941. 展开更多
关键词 characteristic atom-pair holographic code quantitative structure-chromatographic retention relationship characterization of molecular structure partial least-square regression
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Structured Sparse Coding With the Group Log-regularizer for Key Frame Extraction 被引量:1
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作者 Zhenni Li Yujie Li +2 位作者 Benying Tan Shuxue Ding Shengli Xie 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2022年第10期1818-1830,共13页
Key frame extraction based on sparse coding can reduce the redundancy of continuous frames and concisely express the entire video.However,how to develop a key frame extraction algorithm that can automatically extract ... Key frame extraction based on sparse coding can reduce the redundancy of continuous frames and concisely express the entire video.However,how to develop a key frame extraction algorithm that can automatically extract a few frames with a low reconstruction error remains a challenge.In this paper,we propose a novel model of structured sparse-codingbased key frame extraction,wherein a nonconvex group log-regularizer is used with strong sparsity and a low reconstruction error.To automatically extract key frames,a decomposition scheme is designed to separate the sparse coefficient matrix by rows.The rows enforced by the nonconvex group log-regularizer become zero or nonzero,leading to the learning of the structured sparse coefficient matrix.To solve the nonconvex problems due to the log-regularizer,the difference of convex algorithm(DCA)is employed to decompose the log-regularizer into the difference of two convex functions related to the l1 norm,which can be directly obtained through the proximal operator.Therefore,an efficient structured sparse coding algorithm with the group log-regularizer for key frame extraction is developed,which can automatically extract a few frames directly from the video to represent the entire video with a low reconstruction error.Experimental results demonstrate that the proposed algorithm can extract more accurate key frames from most Sum Me videos compared to the stateof-the-art methods.Furthermore,the proposed algorithm can obtain a higher compression with a nearly 18% increase compared to sparse modeling representation selection(SMRS)and an 8% increase compared to SC-det on the VSUMM dataset. 展开更多
关键词 Difference of convex algorithm(DCA) group logregularizer key frame extraction structured sparse coding
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A Novel Algorithm of Error Check and Code Generation for Structured Flowchart
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作者 Mingcheng Qu Naigang Cui +1 位作者 Xianghu Wu Yongchao Tao 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2017年第4期18-30,共13页
Structured flowchart( SFC) and Automatic code generation based on SFC( CG-SFC) have been widely used in software requirements,design and testing phases. Some CG-SFC tools such as Rhapsody have the ability to build flo... Structured flowchart( SFC) and Automatic code generation based on SFC( CG-SFC) have been widely used in software requirements,design and testing phases. Some CG-SFC tools such as Rhapsody have the ability to build flowchart and generate code,but they do not check whether a given flowchart is correct or structural. For unstructured error ‘goto'statements will be generated randomly. We proposed three algorithms and some error recognition criteria to solve those problems. Structure recognition algorithm can recognize Selection,While/for and do-while structures. Error recognition algorithm incorporating criteria can check all the errors. At last,we develop a CG-SFC system,and compared with existing Rhapsody,it shows that the proposed algorithms are correct and effective. 展开更多
关键词 structureD flowchart CODE generation ERROR CHECK FEATURE RECOGNITION
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A NEW CLASS OF LINEAR CODES WITH TWO-LEVEL STRUCTURE
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作者 Wang Haiyan (Dept. of Educational Communication and Technology, Shanxi Normal Univ., Xi’an 710062) 《Journal of Electronics(China)》 2000年第1期90-93,共4页
The binary extended Golay code has a two-level structure, which can be used in the decoding of the code. However, such structure is not limited to the Golay code, in fact, several binary linear codes can be constructe... The binary extended Golay code has a two-level structure, which can be used in the decoding of the code. However, such structure is not limited to the Golay code, in fact, several binary linear codes can be constructed by a projective method which is related to the structure. In this correspondence, the binary (4n,n + 2k, ≥min(8, n,2d)) linear codes are resulted from quaternary (n,k,d) linear block codes. Based on the structure, the efficient maximum likelihood decoding algorithms can be presented correspondingly for the derived codes. 展开更多
关键词 LINEAR CODE TWO-LEVEL structure GOLAY CODE
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Image Coding Using Wavelet Transform and EntropyConstrained Vector Quantization with Quadtree Structure Vectors
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作者 高西奇 何振亚 《Journal of Southeast University(English Edition)》 EI CAS 1996年第1期19-24,共6页
This paper presents a new wavelet transform image coding method. On the basis of a hierarchical wavelet decomposition of images, entropy constrained vector quantization is employed to encode the wavelet coefficients... This paper presents a new wavelet transform image coding method. On the basis of a hierarchical wavelet decomposition of images, entropy constrained vector quantization is employed to encode the wavelet coefficients at all the high frequency bands with 展开更多
关键词 WAVELET TRANSFORM ENTROPY constrained VECTOR QUANTIZATION QUADTREE structure VECTOR image coding
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HiSC:A Hybrid XML Index Composing Structure-Encoded with Cluster
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作者 YANG Jincai ZHANG Lin 《Wuhan University Journal of Natural Sciences》 CAS 2007年第5期840-844,共5页
A new way of indexing and processing twig patterns in an XML documents is proposed in this paper. Every path in XML document can be transformed into a sequence of labels by Structure-Encoded that constructs a one-to-o... A new way of indexing and processing twig patterns in an XML documents is proposed in this paper. Every path in XML document can be transformed into a sequence of labels by Structure-Encoded that constructs a one-to-one correspondence between XML tree and sequence. Base on identifying characteristics of nodes in XML tree, the elements are classified and clustered. During query proceeding, the twig pattern is also transformed into its Structure-Encoded. By performing subsequence matching on the set of sequences in XML documents, all the occurrences of path in the XML documents are refined. Using the index, the numbers of elements retrieved are minimized. The search results with pertinent format provide more structure information without any false dismissals or false alarms. The index also supports keyword search Experiment results indicate the index has significantly efficiency with high precision. 展开更多
关键词 XML index structure cluster index region coding structure-encoded keyword search
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Screen image sequence compression method utilizing adaptive block size coding and hierarchical GOP structure
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作者 武星 梅亮 +2 位作者 袭奇 张申生 陈延伟 《Journal of Central South University》 SCIE EI CAS 2010年第4期786-794,共9页
To compress screen image sequence in real-time remote and interactive applications,a novel compression method is proposed.The proposed method is named as CABHG.CABHG employs hybrid coding schemes that consist of intra... To compress screen image sequence in real-time remote and interactive applications,a novel compression method is proposed.The proposed method is named as CABHG.CABHG employs hybrid coding schemes that consist of intra-frame and inter-frame coding modes.The intra-frame coding is a rate-distortion optimized adaptive block size that can be also used for the compression of a single screen image.The inter-frame coding utilizes hierarchical group of pictures(GOP) structure to improve system performance during random accesses and fast-backward scans.Experimental results demonstrate that the proposed CABHG method has approximately 47%-48% higher compression ratio and 46%-53% lower CPU utilization than professional screen image sequence codecs such as TechSmith Ensharpen codec and Sorenson 3 codec.Compared with general video codecs such as H.264 codec,XviD MPEG-4 codec and Apple's Animation codec,CABHG also shows 87%-88% higher compression ratio and 64%-81% lower CPU utilization than these general video codecs. 展开更多
关键词 screen image sequence compression adaptive block size hierarchical GOP structure intra-frame coding inter-frame coding
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Study of Suitability of Out-of-Codes Tall Slab-Column and Shearwall Structure 被引量:1
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作者 GUO Nan ZHAO Tingting LIN Yiying 《沈阳建筑大学学报(自然科学版)》 CAS 北大核心 2012年第6期1014-1022,共9页
The purpose of this paper is to discuss the suitability of out-of-codes tall slab-column and shearwall structure and to popularize the structure in seismic region.In the research,flat-plate floor was used in slab-colu... The purpose of this paper is to discuss the suitability of out-of-codes tall slab-column and shearwall structure and to popularize the structure in seismic region.In the research,flat-plate floor was used in slab-column and shearwall structure in the practical engineering,the key parameters of slab-column and shearwall structure and frame-shearwall structure such as deflection,punching shear behavior,story drift and capability curve were worked out by static plastic analysis,elastic-plastic time history analysis and pushover analysis,then the suitability of out-of-codes tall slab-column and shearwall structure was evaluated.The results show that the out-of-codes tall slab-column and shearwall structure studies could satisfy the require of deflection and punching shear behavior,the story drift under 7 degree expected rare earthquake waves could satisfy the limit value in the codes and the seismic design spectrum was crossed by the capability curve of the structure and the structure could not collapse.The conclusion is that slab-column and shearwall structure with reasonable design built in Ⅱ soil site of intensity 7 seismic fortification zone can be designed higher than the limit height in the codes. 展开更多
关键词 slab-column and shearwall structure finite element analysis SUITABILITY out-of-codes
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Robustness and precision evaluation of the form error of micro-structured surfaces using real coded genetic algorithm 被引量:1
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作者 周京博 孙涛 《Journal of Beijing Institute of Technology》 EI CAS 2012年第4期479-486,共8页
To obtain the form error of micro-structured surfaces robustly and accurately, a form er- ror evaluation method was developed based on the real coded genetic algorithm (RCGA). The meth- od employed the average squar... To obtain the form error of micro-structured surfaces robustly and accurately, a form er- ror evaluation method was developed based on the real coded genetic algorithm (RCGA). The meth- od employed the average squared distance as the matching criterion. The point to surface distance was achieved by use of iterative method and the modeling of RCGA for the surface matching was also presented in detail. Parameter selection for RCGA including the crossover rate and population size was discussed. Evaluation results of series simulated surfaces without form error show that this method can achieve the accuracy of root mean square deviation ( Sq ) less than 1 nm and surface pro- file error ( St ) less than 4 nm. Evaluation of the surfaces with different simulated errors illustrates that the proposed method can also robustly obtain the form error with nano-meter precision. The e- valuation of actual measured surfaces further indicates that the proposed method is capable of pre- cisely evaluating micro-structured surfaces. 展开更多
关键词 micro-structured surfaces form error evaluation surface matching real coded geneticalgorithm
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LOW-DIMENSIONAL STRUCTURES:SP ARSE CODING FOR NEURONAL ACTIVITY
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作者 YUNHUA XU WENWEN BAI XIN TIAN 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2013年第1期44-52,共9页
Neuronal ensemble activity codes working memory.In this work,we developed a neuronal ensemble sparse coding method,which can effectively reduce the dimension of the neuronal activity and express neural coding.Multicha... Neuronal ensemble activity codes working memory.In this work,we developed a neuronal ensemble sparse coding method,which can effectively reduce the dimension of the neuronal activity and express neural coding.Multichannel spike trains were recorded in rat prefrontal cortex during a work memory task in Y-maze.As discretesignals,spikes were transferred into cont inuous signals by estinating entropy.Then the normalized continuous signals were decomposed via non-negative sparse met hod.The non-negative components were extracted to reconstruct a low-dimensional ensemble,while none of the feature components were missed.The results showed that,for well-trained rats,neuronal ensemble activities in the prefrontal cortex changed dynamically during the.working memory task.And the neuronal ensemble is more explicit via using non-negative sparse coding.Our results indicate that the neuronal ensemblesparse coding method can effectively reduce the dimnension of neuronal activity and it is a useful tool to express neural coding. 展开更多
关键词 Low dimensional structures sparse coding neuronal ensemble activity working memory RAT
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Research and Application of Code Automatic Generation Algorithm Based on Structured Flowchart
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作者 Xiang-Hu Wu Ming-Cheng Qu +1 位作者 Zhi-Qiang Liu Jian-Zhong Li 《Journal of Software Engineering and Applications》 2011年第9期534-545,共12页
It is of great significance to automatically generate code from structured flowchart. There are some deficiencies in existing researches, and their key algorithms and technologies are not elaborated, also there are ve... It is of great significance to automatically generate code from structured flowchart. There are some deficiencies in existing researches, and their key algorithms and technologies are not elaborated, also there are very few full-featured integrated development platforms that can generate code automatically based on structured flowchart. By analyzing the characteristics of structured flowchart, a structure identification algorithm for structured flowchart is put forward. The correctness of algorithm is verified by enumeration iteration. Then taking the identified flowchart as input, an automatic code generation algorithm is proposed. Also the correctness is verified by enumeration iteration. Finally an integrated development platform is developed using those algorithms, including flowchart modeling, code automatic generation, CDT\GCC\GDB etc. The correctness and effectiveness of algorithms proposed are verified through practical operations. 展开更多
关键词 AUTOMATIC GENERATION of CODES structureD Flowchart Identification of structure INTEGRATED Development PLATFORM
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Projecting Distortion Calibration and Evaluation of Coding Fringes in Structured Light System
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作者 Haibin Wu Qing Xu +3 位作者 Xi Wu Guanglu Sun Xiaoyang Yu Xiaoming Sun 《国际计算机前沿大会会议论文集》 2016年第1期139-140,共2页
Coded structured light is an accurate, fast 3D measurement approach with high sampling density, of which the encoded fringes are distorted when projected to curved surface. Focused on the demand of encoding, decoding,... Coded structured light is an accurate, fast 3D measurement approach with high sampling density, of which the encoded fringes are distorted when projected to curved surface. Focused on the demand of encoding, decoding, multiview registration and system calibration, we expect to obtain undistorted fringes from camera image. Therefore, in this paper, we analyze the accuracy and sampling density of projecting distortion calibration approach based on control point and fitting surface. Moreover, combining the characteristic of coded structured light system, we design encoded fringe projecting distortion calibration scheme based on simplified encoded structured light model. Primarily, we neglect the minor parameters that affect the calibration in structured light model to reduce complexity. Then, we build the correspondence between camera image points and projector image points and achieve the calibration. Finally, we design evaluation scheme of projecting distortion calibration with parallelism and equal interval, and verify the effectiveness and accuracy of the approach through visual effect and experimental data. 展开更多
关键词 CODED structured light Projecting DISTORTION GEOMETRIC CALIBRATION Encoded FRINGE
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Efficient tracker based on sparse coding with Euclidean local structure-based constraint
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作者 WANG Hongyuan ZHANG Ji CHEN Fuhua 《智能系统学报》 CSCD 北大核心 2016年第1期136-147,共12页
Abstract:Sparse coding(SC)based visual tracking(l1-tracker)is gaining increasing attention,and many related algorithms are developed.In these algorithms,each candidate region is sparsely represented as a set of target... Abstract:Sparse coding(SC)based visual tracking(l1-tracker)is gaining increasing attention,and many related algorithms are developed.In these algorithms,each candidate region is sparsely represented as a set of target templates.However,the structure connecting these candidate regions is usually ignored.Lu proposed an NLSSC-tracker with non-local self-similarity sparse coding to address this issue,which has a high computational cost.In this study,we propose an Euclidean local-structure constraint based sparse coding tracker with a smoothed Euclidean local structure.With this tracker,the optimization procedure is transformed to a small-scale l1-optimization problem,significantly reducing the computational cost.Extensive experimental results on visual tracking demonstrate the eectiveness and efficiency of the proposed algorithm. 展开更多
关键词 euclidean LOCAL-structure CONSTRAINT l1-tracker SPARSE coding target tracking
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Band structures of TiO_2 doped with N, C and B 被引量:6
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作者 XU Tian-hua SONG Chen-lu LIU Yong HAN Gao-rong 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2006年第4期299-303,共5页
This study on the band structures and charge densities of nitrogen (N)-, carbon (C)- and boron (B)-doped titanium dioxide (TiO2) by first-principles simulation with the CASTEP code (Segall et al., 2002) showed that th... This study on the band structures and charge densities of nitrogen (N)-, carbon (C)- and boron (B)-doped titanium dioxide (TiO2) by first-principles simulation with the CASTEP code (Segall et al., 2002) showed that the three 2p bands of im-purity atom are located above the valence-band maximum and below the Ti 3d bands, and that along with the decreasing of im-purity atomic number, the fluctuations become more intensive. We cannot observe obvious band-gap narrowing in our result. Therefore, the cause of absorption in visible light might be the isolated impurity atom 2p states in band-gap rather than the band-gap narrowing. 展开更多
关键词 CASTEP code Titanium dioxide Band structure Charge density
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Seismological study on the crustal structure of Tengchong volcanic-geothermal area 被引量:4
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作者 王椿镛 楼海 +3 位作者 吴建平 白志明 皇甫岗 秦嘉政 《Acta Seismologica Sinica(English Edition)》 CSCD 2002年第3期247-259,共13页
Based upon the deep seismic sounding profile conducted in the Tengchong volcanic-geothermal area, a two-dimensional crustal P velocity structure is obtained by use of the finite-difference inversion and the forward tr... Based upon the deep seismic sounding profile conducted in the Tengchong volcanic-geothermal area, a two-dimensional crustal P velocity structure is obtained by use of the finite-difference inversion and the forward travel-time fitting method. The crustal model shows that there is a low velocity zone in upper crust in the Tengchong area, which may be related to the volcanic-geothermal activities, and two intracrustal faults (the LonglingRuili fault and Tengchong fault) exist on the profile, where the Tengchong fault may extend to the Moho discontinuity. Meanwhile, based on teleseismic data recorded by a temporary seismic network, we obtained the S-wave velocity structures beneath the RehaiRetian region in the Tengchong area, which show the low S-wave velocity anomaly in upper crust. The authors discuss the causes of Tengchong volcanic eruption based on the deep crustal structure. The crustal structure in the Tengchong volcanic-geothermal area is characterized by low P-wave and S-wave velocity, low resistivity, high heat-flow value and low Q value. The P-wave velocity in the upper mantle is also low. For this information, it can be induced that the magma in the crust is derived from the upper mantle, and the low velocity anomaly in upper crust in the Tengchong area may be related to the differentiation of magma. The Tengchong volcanoes are close to an active plate boundary and belong to plate boundary volcanoes. 展开更多
关键词 Tengchong volcanic area crustal structure deep seismic sounding travel-time fitting teleseismic waveform CLC number: P315.63 Document code: A
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The structural analysis of protein sequences based on the quasi-amino acids code 被引量:2
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作者 朱平 唐旭清 徐振源 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第1期363-369,共7页
Proteomics is the study of proteins and their interactions in a cell. With the successful completion of the Human Cenome Project, it comes the postgenome era when the proteomics technology is emerging. This paper stud... Proteomics is the study of proteins and their interactions in a cell. With the successful completion of the Human Cenome Project, it comes the postgenome era when the proteomics technology is emerging. This paper studies protein molecule from the algebraic point of view. The algebraic system (∑, +, *) is introduced, where ∑ is the set of 64 codons. According to the characteristics of (∑, +, *), a novel quasi-amino acids code classification method is introduced and the corresponding algebraic operation table over the set ZU of the 16 kinds of quasi-amino acids is established. The internal relation is revealed about quasi-amino acids. The results show that there exist some very close correlations between the properties of the quasi-amino acids and the codon. All these correlation relationships may play an important part in establishing the logic relationship between codons and the quasi-amino acids during the course of life origination. According to Ma F et al (2003 J. Anhui Agricultural University 30 439), the corresponding relation and the excellent properties about amino acids code are very difficult to observe. The present paper shows that (ZU, +,×) is a field. Furthermore, the operational results display that the eodon tga has different property from other stop codons. In fact, in the mitochondrion from human and ox genomic codon, tga is just tryptophane, is not the stop codon like in other genetic code, it is the case of the Chen W C et al (2002 Acta Biophysiea Siniea 18(1) 87). The present theory avoids some inexplicable events of the 20 kinds of amino acids code, in other words it solves the problem of 'the 64 codon assignments of mRNA to amino acids is probably completely wrong' proposed by Yang (2006 Progress in Modern Biomedicine 6 3). 展开更多
关键词 algebraic operation quasi-amino acids code protein sequences structural analysis
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3D surface reconstruction based on binocular vision using structured light 被引量:1
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作者 MA Zhi-feng HAN Fu-hai WANG Teng-fei 《Journal of Beijing Institute of Technology》 EI CAS 2016年第3期413-417,共5页
A 3D surface reconstruction method using a binocular stereo vision technology and a coded structured light,which combines a gray code with phase-shift has been studied.The accuracy of the 3 D surface reconstruction ma... A 3D surface reconstruction method using a binocular stereo vision technology and a coded structured light,which combines a gray code with phase-shift has been studied.The accuracy of the 3 D surface reconstruction mainly depends on the decoding of gray code views and phase-shift views.In order to find the boundary accurately,gray code patterns and their inverses are projected onto a human eye plaster model.The period dislocation between the gray code views and the phase-shift views in the course of decoding has been analyzed and a new method has been proposed to solve it.The splicing method is based on feature points.The result of the 3D surface reconstruction shows the accuracy and reliability of our method. 展开更多
关键词 3D surface reconstruction structured light gray code PHASE-SHIFT
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The Authority Structure of Environmental Regulation under the Codification of Environmental Law 被引量:1
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作者 Chen Demin Zhou Xian 《学术界》 CSSCI 北大核心 2020年第11期193-202,共10页
When developing and integrating a new environmental legal system under the Environmental Code,the joint regulation of ecology and environment,natural resources and an energy beyond the sphere of mere environmental con... When developing and integrating a new environmental legal system under the Environmental Code,the joint regulation of ecology and environment,natural resources and an energy beyond the sphere of mere environmental concerns can be achieved;the semantic expression of environmental regulation can be expounded.Additionally,through the codification of environmental law,a revolutionary path for the structure of authority can be found.Environmental codification dictates a method for clarification of the boundaries and relations of environmental management authority.Under the theory of Holistic Governance and in the codification process,the reform of environmental regulation authority should be concluded from both vertical and horizontal dimensions,through organizing,integrating,separating,classifying and finally,by establishing a synergy between the central and local governments and their departments.This can break down structural barriers to communication and cooperation of the ecological regulation and resource management authority and help establish uniformity of environmental regulation. 展开更多
关键词 COORDINATION UNIFORMITY Holistic Governance Environmental Code authority structure
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Protein structural codes and nucleation sites for protein folding
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作者 江凡 李南 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第2期392-404,共13页
One of the long-standing controversial arguments in protein folding is Levinthal's paradox. We have recently proposed a new nucleation hypothesis and shown that the nucleation residues are the most conserved sequence... One of the long-standing controversial arguments in protein folding is Levinthal's paradox. We have recently proposed a new nucleation hypothesis and shown that the nucleation residues are the most conserved sequences in protein. To avoid the complicated effect of tertiary interactions, we limit our search for structural codes to the nucleation residues. Starting with the hypotheses of secondary structure nucleation and conservation of residues important for folding, we have analysed 762 folds classified as unique by SCOP. Segments of 17 residues around the top 20% conserved amino acids are analysed, resulting in approximately 100 clusters each for the main secondary structure classes of helix, sheet and coil. Helical clusters have the longest correlation range, coils the shortest (four residues). Strong specific sequence-structure correlation is observed for coil but not for helix and sheet, suggesting a mapping relationship between the sequence and the structure for coil. We propose that the central sequences in these clusters form 'structural codes', a useful basis set for identifying nucleation sites, protein fragments stable in isolation, and secondary structural patterns in proteins (particularly turns and loops). 展开更多
关键词 NUCLEATION hydrogen bond secondary structure structural code protein folding sequence-structure relationship
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Preparation , Structure and DC Conductivity of Organic Semiconductor PA NI-C_4H_6O_6
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作者 AdulkaderM.Elamin YAOKai-lun 《Semiconductor Photonics and Technology》 CAS 1999年第3期166-170,共5页
A new organic semiconductor tartaric acid doped salt of emeraldine polyaniline (PANI-C 4H 6O 6) has been obtained by the method of oxidative polymerization of monomeric aniline with ammonium persulfate in acidic solut... A new organic semiconductor tartaric acid doped salt of emeraldine polyaniline (PANI-C 4H 6O 6) has been obtained by the method of oxidative polymerization of monomeric aniline with ammonium persulfate in acidic solution. The structure was characterized by Fourier Transform Infrared technique (FTIR) and X-ray diffraction (XRD). The temperature dependence dc conductivity δ dc ( T ) shows a semiconductor behavior and follows the quasi one dimensional variable range hopping (Q1D-VRH) model. Data on δ dc ( T ) are also discussed. 展开更多
关键词 DC Conductivity Organic Semiconductor Polyaniline structure Tartaric Acid CLC number:O631.23 O632.7 TN304.52 Document code:A
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