检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

基于一种最优核鉴别矢量集的雷达目标识别

系统仿真学报 2008年第20期20卷 5506-5510,5515页

作者：赵峰张军英刘敬山东工商学院计算机学院山东烟台264005 西安电子科技大学计算机学院陕西西安710071

基于高分辨距离像的雷达目标识别的关键是如何提取距离像的有效鉴别特征。通过分析核Fisher准则函数下核类内散布矩阵的零空间信息与非零空间信息对识别的贡献,基于同构映射思想,求解出一组最优鉴别矢量集,用于提取距离像的鉴别特征。同... 详细信息

基于高分辨距离像的雷达目标识别的关键是如何提取距离像的有效鉴别特征。通过分析核Fisher准则函数下核类内散布矩阵的零空间信息与非零空间信息对识别的贡献,基于同构映射思想,求解出一组最优鉴别矢量集,用于提取距离像的鉴别特征。同时,给出一种快速算法,用较少的训练样本表达投影方向,加快了鉴别特征的提取速度。基于外场实测数据的实验证明了方法的有效性。

关键词：高分辨距离像最优鉴别矢量集核Fisher判别分析核函数

Factors Relating with Fertilization Failure in Conventional IVF-ET Cycles

在线全文

学校读者我要写书评

暂无评论

Journal of Reproduction and Contraception 2012年第4期23卷 245-253页

作者： Yuan ZHU Qiong-fang WU Cai-lin XIN Yan ZHAO Guang-xiu LU Institute of Reproduction and Stem Cell engineering Central South University The Reproductive centre of the Women and Children Hospital of Jiangxi Province

Objective To analyze the factors relating with fertilization failure in conventional IVF cycles. Methods The total fertilization failure rate of 2.42. IVF cycles from January 2.11 to May 2.12.in the Reproductive centre of the Women and Children Hospital of Jiangxi Province were retrospectively analyzed. Risk factors were identified by univariate and multivariate logistic regression analyses. Results The total fertilization failure rate of conventional IVF-ET rate was 5. 7% （139/ 2.42.）. Thepercentage of morphologically normal sperm （11.1 ±5.8% vs 13.4 ±5.3%）, progressive motility （47.4± 10.5% vs 50.1 ±8.6%）, percentage of couple primary infertility （79.1% vs 44.3%）, percentage o f female primary infertility （69.1% vs 36.3%）, percentage of male primary infertility （74.8% vs 41.7%）, percentage of without oviduct obstruction patients （30.2. vs 13.6%） and percentage of couples primary infertility （79. 1% vs 44. 3%） of the fertilization failure patients were significantly different from those of the fertilized patients （P〈O.05）. Besides, higher total fertilization failure rate was found in couples with isolated teratozoospermia than in couples with normal percentage of morphologically normal sperm （15.0% vs 5.2.）. After that, it was found by multivariate logistic regression analyses that many factors including percentage of morphologically normal sperm, sperm concentration, couples primary infertility and female infertility years were related with fertilization failure. Conclusion Patients with low percentage of morphologically normal sperm （〈4%）, low sperm concentration and motility, male primary infertility, female primary infertility, without oviduct obstruction, long female infertility years or/and couples primary infertility are at high risk of fertilization failure. More attention should be paid to these patients for avoiding the fertilization failure.

关键词： isolated teratozoospermia spermatozoa chromosome aneuploidy

Relationship between Multi-Phase Formation and Molecular Structure for Liquid Crystal System

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2005年第3期20卷 11-13页

作者：李振新 Biomedical Materials and engineering centre Wuhan University of Technology Department of Life Science and Technology Xinxiang Medicine CollegeXinxiang 453003 China

4 mechanical model of liquid crystals （ LCs ） was used to explain the phase formation and thermal properties . The LC plusses in the model are micro- machine systems consisting of an ensemble of molecular rotors, and some dynamie parameters in a semi-experiment molecular orbit method. A novel explanation on the multi-phase formation of LC system is obtained. It is found that the value of the critical rotational velueity is a key parameter for the characterization of each homologous series. The dipole moment of the molecules was also discussed.

关键词： liquid crystal phase dynamic molecular structure

The effects of the false vocal fold gaps on intralaryngeal pressure distributions and their effects on phonation

在线全文

学校读者我要写书评

暂无评论

Science china.Life Sciences) 2008年第11期51卷 1045-1051页

作者： LI Sheng1,2. WAN MingXi1 & WANG SuPin1 1 Key Laboratory of Biomedical Information engineering of Ministry of Education, Department of Biomedical engineering, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an 710049, {2.2.Department of Biomedical engineering, Fourth Military Medical University, Xi’an 710032. china Key Laboratory of Biomedical Information engineering of Ministry of Education Department of Biomedical Engineering School of Life Science and Technology Xi’an Jiaotong University Xi’an China Department of Biomedical engineering Fourth Military Medical University Xi’an China

Human phonation does not merely depend on the vibration of the vocal folds. Research by clinical and computer simulations has demonstrated that the false vocal fold (FVF) is an important laryngeal con-striction that plays a vital role during human voice production. This study explored the effects of the FVF gaps using both the three-dimensional Plexiglas model and the numerical computation methods. Twelve FVF gaps (ranging from 0.02.to 2.06 cm) were used in this study at three glottal angles (uniform and convergent/divergent 40°), two minimal glottal diameters (Dg) (0.04 cm and 0.06 cm) separately, and the constant subglottal pressure (8 cm H2.). The results suggested that (1) the intralaryngeal pressure was the lowest and the flow was the highest (least flow resistance) when the FVF gap was 1.5-2.times greater than Dg; (2. the divergent glottal angle gave lower pressure and greater flow than the conver-gent and uniform glottal angle as there were no FVF conditions; (3) the presence of the FVF decreased the effects of the glottal angle to a certain extent; and more importantly, (4) the presence of the FVF also moved the separation points downstream, straightened the glottal jet for a longer distance, decreased the overall laryngeal resistance, and reduced the energy dissipation, suggesting the significance of FVF in efficient voice production. These results may be incorporated in the phonatory models (physical or computational) for better understanding of vocal mechanics. The results might also be helpful in exploring the surgical and rehabilitative intervention of related voice problems.

关键词： false vocal fold laryngeal physical model aerodynamics modeling phonation

NUMERICAL SOLUTION OF THE UNSTEADYINCOMPRESSIBLE NAVIER-STOKES EQUATIONS ON THECURVILINEAR HALF-STAGGERED MESHNUMERICAL SOLUTION OF THE UNSTEADYINCOMPRESSIBLE NAVIER-STOKES EQUATIONS ON THECURVILINEAR HALF-STAGGERED MESH

在线全文

学校读者我要写书评

暂无评论

Journal of computational Mathematics 2000年第5期18卷 521-540页

作者： Lan-chieh Huang (Institute of computational Mathematics and Scientific/engineering Computing, Chinese Academy of Sciences, Beijing 100080, {2. 中科院计算数学与科学工程计算所北京 100080

In this paper, the Crank-Nicholson + component-consistent pressure correction method for the numerical solution of the unsteady incompressible Navier-Stokes equation of [1] on the rectangular half-Staggered mesh has been extended to the curvilinear half-Staggered mesh. The discrete projection, both for the projection step in the solution procedure and for the related differential-algebraic equations, has been carefully studied and verified. It is proved that the proposed method is also unconditionally (in t) nonlinearly stable on the curvilinear mesh, provided the mesh is not too skewed. It is seen that for problems with an outflow boundary, the half-Staggered mesh is especially advantageous. Results of preliminary numerical experiments support these claims.

关键词： Unsteady incompressible Navier-Stokes equations Curvilinear half- staggered mesh Discrete projection.

Fast parallel algorithms for discrete Gabor expansion and transform based on multirate filtering

在线全文

学校读者我要写书评

暂无评论

Science china.Information Sciences) 2012年第2期55卷 293-300页

作者： TAO Liang1 & GU JuanJuan2.1School of Computer Science and Technology,Anhui University,Hefei 2.0039,china.2.epartment of Electronic Information and Electrical engineering,Hefei University,Hefei 2.002.,{2. School of Computer Science and Technology Anhui University Hefei China Department of Electronic Information and Electrical engineering Hefei University Hefei China

The Gabor transform has long been recognized as a very useful tool for the joint time and frequency analysis in signal *** real time applications,however,were limited due to the high computational complexity of the Gabor transform *** this paper,some novel and fast parallel algorithms for the finite discrete Gabor expansion and transform are presented based on multirate *** analysis filter bank is designed for the finite discrete Gabor transform(DGT)and a synthesis filter bank is designed for the finite discrete Gabor expansion(DGE).Each of the parallel channels in the two filter banks has a unified structure and can apply the FFT and the IFFT to reduce its computational *** computational complexity of each parallel channel does not change as the oversampling rate *** fact,it is very low and depends only on the length of the input discrete signal and the number of the Gabor frequency sampling *** computational complexity of the proposed parallel algorithms is analyzed and compared with that of the major existing parallel algorithms for the finite DGT and *** results indicate that the proposed parallel algorithms for the finite DGT and DGE based on multirate filtering are very attractive for real time signal processing.

关键词： discrete Gabor expansion discrete Gabor transform critical sampling and oversampling multirate filtering analysis and synthesis filter banks

Advances in numerical methods for the solution of population balance equations for disperse phase systems

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.Chemistry 2009年第8期52卷 1063-1079页

作者： SU JunWei1,GU ZhaoLin2.3 & XU X.Yun41 Department of Mechanical engineering and Automation,School of Mechanical engineering,Xi’an Jiaotong University,Xi’an 710049,{2.2.Key Laboratory of Mechanics on Disaster and Environment in Western {2.Ministry of Education,Lanzhou 730000,{2.3 Department of Environmental Science and Technology,School of Human Settlements and Civil engineering,Xi’an Jiaotong University,Xi’an 710049,{2.4 Department of Chemical engineering,Imperial College London,London SW7 2.Z,UK Department of Mechanical engineering and Automation School of Mechanical Engineering Xi’an Jiaotong University Xi’an China Key Laboratory of Mechanics on Disaster and Environment in Western china Ministry of Education Lanzhou China Department of Environmental Science and Technology School of Human Settlements and Civil Engineering Xi’an Jiaotong University Xi’an China Department of Chemical engineering Imperial College London London UK

Accurate prediction of the evolution of particle size distribution is critical to determining the dynamic flow structure of a disperse phase system.A population balance equation(PBE),a non-linear hyperbolic equation of the number density function,is usually employed to describe the micro-behavior(aggregation,breakage,growth,etc.) of a disperse phase and its effect on particle size *** solution is the only choice in most *** this paper,three different numerical methods(direct discretization methods,Monte Carlo methods,and moment methods) for the solution of a PBE are evaluated with regard to their ease of implementation,computational load and numerical *** attention is paid to the relatively new and superior moment methods including quadrature method of moments(QMOM),direct quadrature method of moments(DQMOM),modified quadrature method of moments(M-QMOM),adaptive direct quadrature method of moments(ADQMOM),fixed pivot quadrature method of moments(FPQMOM),moving particle ensemble method(MPEM) and local fixed pivot quadrature method of moments(LFPQMOM).The prospects of these methods are discussed in the final section,based on their individual merits and current state of development of the field.

关键词： population balance equation direct discretization method Monte Carlo method moment methods disperse phase system

Effective use of the spectral information in speech processing of cochlear implant

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第3期17卷 334-339页

作者： GUAN Tian, GONG Qin and YE Datian ( Joint Research centre for Biomedical engineering, Department of Electronic engineering, The Chinese University of Hong Kong, Hong Kong, china.Research centre of Biomedical engineering, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, china. Joint Research centre for Biomedical engineering Department of Electronic Engineering The Chinese University of Hong Kong Hong Kong Research centre of Biomedical engineering Graduate School at Shenzhen Tsinghua University Shenzhen 518055 China

Based on the results of the acoustic research on Mandarin, two novel algorithms using the spectral information in speech processing of cochlear implants are purposed and certified effectively by the spectral information of tonal language in acoustic simulation experiments. We bring forward novel algorithms conveying the spectral information based on the choices of the frequency bands. These new algorithms can not only improve the speech recognition ability of cochlear implant users in the noisy environments but also reduce the complexity of computing and the memory occupied, and make it more suitable to be carried out in clinical practice.

关键词： cochlear implant speech signal processing signal processing.

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

基于联想记忆的直觉产生的模拟方法

系统工程与电子技术 2004年第10期26卷 1491-1494页

作者：赵婷婷魏小鹏大连理工大学机械工程学院辽宁大连116023 大连大学先进设计技术中心辽宁大连116622

针对直觉在创新思维产生过程中的重要作用,对直觉的模拟提供了创新计算的一种新方法。采用Hopfield神经网络以及交叉变异等实现方法,对直觉、经验、联想和可视激励之间的相互关系进行了定量描述,提出了变异联想产生直觉的观点,从而建立... 详细信息

针对直觉在创新思维产生过程中的重要作用,对直觉的模拟提供了创新计算的一种新方法。采用Hopfield神经网络以及交叉变异等实现方法,对直觉、经验、联想和可视激励之间的相互关系进行了定量描述,提出了变异联想产生直觉的观点,从而建立了模拟直觉的认知模型以及计算模型。最后给出了利用直觉模型生成新分形图的应用实例,计算结果表明此算法能够实现创新。

关键词： Hopfield神经网络直觉联想变异