检索结果-南通市图书馆

A cumulant-based parameter estimation algorithm for near-field sources

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 2007年第8期17卷 900-905页

作者： Liang Junli~(1,2*) Yang Shuyuan~(1,2) Zhang Junying~3 (1.Institute of Acoustics,chinese academy of sciences,beijing 100080,china 2.graduate school,chinese academy of sciences,beijing 100039,china 3.National Laboratory of Radar Signal Processing,Xidian University,Xi'an 710071,china) Institute of Acoustics Chinese Acad. of Sci. Beijing 100080 China graduate school Chinese Acad. of Sci. Beijing 100039 China National Laboratory of Radar Signal Processing Xidian University Xi'an 710071 China

To efficiently use the array aperture and avoid the complicated parameter pairing computation,this paper proposes a new cumulant-based algorithm for localizing near-field narrowband ***,this algorithm proposes a symmetric uniform linear ar- ray (ULA),and constructs three cumulant matrices by using the fourth-order cumulants of some properly chosen sensor outputs;second- ly,unlike the conventional parallel factor (PARAFAC) analysis models in data or subspace domain,it forms a three-way array (TWA) in the fourth-order cumulant domain using the three matrices,and analyzes the uniqueness of its low-rank decomposition;thirdly,it jointly estimates the frequency,the direction-of-arrival (DOA),and the range of each near-field source from the matrices via the low-rank de- composition of the *** simulation results are presented to validate the performance of our proposed method.

关键词： array signal processing localization cumulant parallel factor (PARAFAC) analysis three-way array (TWA)

Improved K-means Algorithm for Manufacturing Process Anomaly Detection and Recognition

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

武汉理工大学学报 2006年第S3期28卷 1036-1041页

作者： ZHOU Xiaomin~(1,2) PENG Wei~1 SHI Haibo~1 (1.Shenyang Institution of Automation chinese academy of sciences,Shenyang 110016,china, 2.graduate school,chinese academy of sciences,beijing 100039,china) Shenyang Institution of Automation chinese academy of sciences Shenyang 110016China graduate school Chinese Academy of SciencesBeijing 100039China Shenyang Institution of Automation chinese academy of sciences Shenyang 110016China

Anomaly detection and recognition are of prime importance in process *** are usually rare,and, therefore,predicting them is *** this paper,a new greedy initialization method for the K-means algorithm is proposed to improve traditional K-means clustering *** new initialization method tries to choose suitable initial points,which are well separated and have the potential to form high-quality *** on the clustering result of historical disqualification product data in manufacturing process which generated by the Improved-K-means algorithm,a prediction model which is used to detect and recognize the abnormal trend of the quality problems is *** simple and robust alarm-system architecture for predicting incoming faults realizes the transition of quality problems from diagnosis afterward to prevention beforehand *** the end,the alarm model was applied for prediction and avoidance of gear-wheel assembly faults at a gear-plant.

关键词： data mining clustering quality management anomaly detection and recognition

Numerical Simulation of Multi-track and Multi-layer Temperature Field on Laser Direct Metal Shaping

在线全文

学校读者我要写书评

暂无评论

武汉理工大学学报 2006年第S3期28卷 1111-1116页

作者： LONG Risheng~(1,2) LIU Weijun~1 (1.Advanced Manufacture Lab,Shenyang Institute of Automation,Shenyang 110016,china, 2.graduate school,chinese academy of sciences,beijing 100039,china) Advanced Manufacture Lab Shenyang Institute of AutomationShenyang 110016China Advanced Manufacture Lab Shenyang Institute of AutomationShenyang 110016China graduate school Chinese Academy of SciencesBeijing 100039China

To improve the mechanical properties of the parts fabricated by Laser Direct Metal Shaping(LDMS),it is of great significance to understand the distribution regularities of transient temperature field during LDMS *** on the“el- ement birth and death”technique of finite element method,a three-dimensional multi-track and multi-layer model for the transient temperature field analysis of LDMS is developed by ANSYS Parametric Design Language(APDL)for the first *** the fab- ricated modal,X-direction parallel reciprocating scanning paths is *** the same process parameters,the simulation results show good agreement with the microstructure features of samples which fabricated by LDMS.

关键词： laser direct metal shaping transient temperature field numerical simulation

Numerical Simulation of Transient Thermal Stress Field for Laser Metal Deposition Shaping

在线全文

学校读者我要写书评

暂无评论

武汉理工大学学报 2006年第S3期28卷 1025-1030页

作者： LONG Risheng~(1,2) LIU Weijun~1 (1.Advanced Manufacture Lab,Shenyang Institute of Automation,Shenyang 110016,china 2.graduate school,chinese academy or sciences,beijing 100039,china) Advanced Manufacture Lab Shenyang Institute of AutomationShenyang 110016China graduate school Chinese Academy of SciencesBeijing 100039China Advanced Manufacture Lab Shenyang Institute of AutomationShenyang 110016China

To decrease thermal stress during laser metal deposition shaping(LMDS)process,it is of great importance to learn the transient thermal stress distribution *** on the“element life and death”technique of finite element analy- sis(FEA),a three-dimensional multi-track and multi-layer numerical simulation model for LMDS is developed with ANSYS parametric design language(APDL)for the first time,in which long-edge parallel reciprocating scanning paths is introduced. Through the model,detailed simulations of thermal stress during whole metal cladding process are conducted,the generation and distribution regularities of thermal stress are also discussed in *** the same process parameters,the simulation results show good agreement with the features of samples which fabricated by LMDS.

关键词： LMDS FEA transient thermal stress field numerical simulation

Solid State Polymer Electrolytes for Dye-sensitized Solar Cell

在线全文

学校读者我要写书评

暂无评论

复旦学报（自然科学版） 2007年第5期46卷 660-661页

作者： Xiong Yin1,2, Wanchun Xiang1,2, Xurui Xiao1, Yuan Lin1, Shibi Fang1(1.Key Laboratory of Photochemistry, Institute of Chemistry, chinese academy of sciences, beijing 100080, china 2.graduate school of chinese academy of sciences, beijing 100039, china) Institute of Chemistry Chinese Academy of Sciences Key Laboratory of Photochemistry Chinese Academy of Sciences Beijing 100080

1 Introduction Over the past decade,Dye-sensitized solar cells (DSSCs) have been intensively investigated as potential alternatives to conventional inorganic photovoltaic devices due to their low production cost and high energy conversion[1-4]. This type of solar cell has achieved an impressive energy conversion efficiency of over 10%,whose electrolyte is a voltaic organic liquid solvent containing iodide/triiodide as redox ***,the use of a liquid electrolyte brings difficulties in the practi...

关键词： dye-sensitized solar cell chemically cross-linked gel polymer electrolyte quaternization reaction

Research on Forging Die Design Ontology

在线全文

学校读者我要写书评

暂无评论

武汉理工大学学报 2006年第S2期28卷 640-645页

作者： ZHANG Wenlei~(1.2) FAN Yushun~3 1.2nd Dept.Shenyang Institute of Automation,chinese academy of Science,Shenyang 110016,china 2.graduate school of chinese academy of sciences,beijing 100039,china 3.Department of Automation,Tsinghua University,beijing 100084,china 2nd Dept.Shenyang Institute of Automation Chinese Academy of ScienceShenyang 110016China graduate school of chinese academy of sciences Beijing 100039China Department of Automation Tsinghua UniversityBeijing 100084China

Forging die design is heavily dependent on engineers’ *** traditional AI technologies can barely pro- vide a standard knowledge representation style for knowledge *** paper introduces ontology into forging die design. 3-layer forging die design ontology is built,which includes Meta-ontology,Domain-ontology and Bottom ***,by conceptualization,the concepts and their relations are formally addressed by primitives such as Term,Relation and Function etc, which are explicitly expressed by concept *** ontology uses Knowledge Item and Prototype to represent and capture general knowledge for knowledge reuse and *** die design ontology building approach is discussed for standard knowledge repre- sentation,knowledge mine and knowledge driven CAD design *** OWL language is employed for integration among different domain ontologies *** a locomotive forging die KBE system is presented to demonstrate this approach.

关键词： ontology forging die KBE CAD

Phylogenetic studies of chinese labeonine fishes(Teleostei: Cyprinidae)based on the mitochondrial16S rRNA gene

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第3期 21-27页

作者： LI Junbing 1,2 ,WANG Xuzhen 1 ,HE Shunping 1ˇˇ and CHEN Yiyu 1 (1.Institute of Hydrobiology,chinese academy of sciences,Wuhan430072,china 2.graduate school of the chinese academy of sciences,beijing100039,china) Institute of Hydrobiology，chinese academy of sciences，Wuhan 430072，china graduate school of the chinese academy of sciences，beijing 100039，china Institute of Hydrobiology，chinese academy of sciences，Wuhan 430072，china

The mitochondrial16S ribosomal RNA gene is sequenced from24ingroups taxa,including18species from Labeoninae grouped *** analyses are subjected to neighbor joining,maximum parsimony,maximum likelihood and Bayesian *** analysis indicates that Labeoninae is basically a monophyletic assemblage and can be divided into2major clades:one comprising the genera Cirrhinus,Crossocheilus and Garra;and the other consisting of the genera Labeo,Sinilabeo,Osteochilus,Pseu-doorossocheilus,Parasinilabeo,Ptychidio,Semilabeo,Pseudogyricheilus,Rectori and *** to our present analysis,the features such as the presence of the adhesive disc on the chin and the pharyngeal teeth in2rows used in the traditional taxonomy of Labeoninae provide scarce information for phylogeny of labeonine fishes.

关键词： 16S rRNA Labeoninae monophyly phylogeny Cyprinidae.

Partial continuation model and its application in mitigating systematic errors of double-differenced GPS measurements

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 2005年第3期 54-59页

作者： GUO Jianfeng 1,2 ˇˇ ,OU Jikun 1 and REN Chao 1 (1.Key Laboratory of Geodynamics,Institute of Geodesy and Geophysics,chinese academy of sciences,Wuhan430077,china 2.graduate school of the chinese academy of sciences,beijing100039,china) Key Laboratory of Geodynamics，Institute of Geodesy and Geophysics，chinese academy of sciences，Wuhan 430077，china graduate school of the chinese academy of sciences，beijing 100039，china Key Laboratory of Geodynamics，Institute of Geodesy and Geophysics，chinese academy of sciences，Wuhan 430077，china

Based on the so-called partial continuation model with exact finite measurements,a new stochastic assessment procedure is *** every satellite pair,the temporal correlation coefficient is estimated using the original double-differenced(DD)GPS *** then,the Durbin-Watson test is applied to test specific hypothesis on the temporal correlation *** the test is not significant with a certain significant level,a data transformation is *** transformed measurements are free of time *** purpose of illustration,two static GPS baseline data sets are analyzed in *** experimental results demonstrate that the proposed procedure can mitigate effectively the impact of systematic errors on DD GPS measurements.

关键词： partial continuation model systematic errors GPS double-differenced measurements.

基于KFD＋ICA特征提取的SAR图像目标识别

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

系统工程与电子技术 2008年第7期30卷 1237-1240页

作者：宦若虹杨汝良中国科学院电子学研究所

提出了一种用基于核函数的Fisher判别分析(kernel based Fisher discriminant analysis,KFD)和独立分量分析(independent component analysis,ICA)特征提取的合成孔径雷达(synthetic aperture radar,SAR)图像目标识别方法。用基于核函数的Fisher判别分析提取SAR图像样本在高维特征空间中的最佳分类向量,对最佳分类向量做独立分量分析,得到表征图像样本的特征向量,用支持向量机(support vector machine,SVM)对提取得到的特征向量分类完成目标识别。对MSTAR数据库中三类军事目标用该方法进行特征提取和识别实验,识别率为96.92%。结果表明,KFD+ICA特征提取方法可提取目标的有效特征,在较低特征维数情况下获得较高的目标正确识别率。

关键词：合成孔径雷达特征提取目标识别基于核函数的Fisher判别分析独立分量分析