Evolutionary level set method for structural topology optimization

This paper proposes an evolutionary accelerated computational level set algorithm for structure topology optimization. It integrates the merits of evolutionary structure optimization (ESO) and level set method (LSM). Traditional LSM algorithm is largely dependent on the initial guess topology. The proposed method combines the merits of ESO techniques with those of LSM algorithm, while allowing new holes to be automatically generated in low strain energy within the nodal neighboring region during optimization. The validity and robustness of the new algorithm are supported by some widely used benchmark examples in topology optimization. Numerical computations show that optimization convergence is accelerated effectively.     

综合业务和区分业务比较研究

为了在Internet上提供有服务质量等级和保证的服务,现在已经提出的在传输层上的实现方案包括综合业务（Integtated Services）和区分业务（Differentiated Services)。本文分析了两种方案的体系结构、工作原理和服务类型,比较了二者在设计思想、实现机制、QoS特性等方面的差异和优缺点,介绍了两种模型相互结合的扩展体系结构及最新研究进展。     

大纯滞后过程的采样控制及其工程实现中的若干问题

提出了采样控制机制的新观点,介绍控制器参数确定的新方法,分析了采样控制的质量,指出了在工程实施应考虑的若干问题。     

一个基于加权和组合降维的web文本分类系统

设计了一个web文本分类系统,采用了基于统计分析和粗糙集组合的方法进行降维;降维时考虑了属性的位置信息,采用加权方式标注属性的不同重要性,以达到提高分类速度和分类准确度的目的。     

Equilibria and their bifurcations in a recurrent neural network involving iterates of a transcendental function.

Some practical models contain so complicated mathematical expressions that it is hard to determine the number and distribution of all equilibria, not mentioning the qualitative properties and bifurcations of those equilibria. The three-node recurrent neural network system with two free weight parameters, originally introduced by Ruiz, Owens, and Townley in 1997, is such a system, for which the equation of equilibria involves transcendental function tanh(x) and its iterates. Not computing coordinates of its equilibria, in this paper, we display an effective technique to determine the number and distribution of its equilibria. Without full information about equilibria, our method enables to further study qualitative properties of those equilibria and discuss their saddle node, pitchfork, and Hopf bifurcations by approximating center manifolds.     

基于用户查询的多关系群体挖掘改进算法

多关系群体挖掘是近年来快速发展的重要的数据挖掘领域之一.传统的群体挖掘方法是假定网络中只有一种关系,并且挖掘结果与用户需求无关.但现实中的社会网络中存在着多种关系.基于用户查询,不同的关系表现出不同的重要性.分析了多关系群体挖掘中关系提取的问题,提出一种新算法对满足用户期望的关系进行最优线性合并.利用获得的合并关系提高群体挖掘的精准性.     

Three-dimensional reconstruction on PC-Windows platform for evaluation of living donor nephrectomy

Evaluation of renal vasculature was necessary for preoperative donor assessment in living donor kidney transplantation, and the ability to view the vascular imaging in three-dimensional (3D) space should be helpful undoubtedly. Considering the widespread use of personal computer (PC) systems, we aimed to find a handy way to display the anatomy of the renal arterial and venous systems of potential donors on PC-Windows platform. Ten living-related donors were included in this study. Serial computed tomography (CT) images were loaded into Amira 3.1 running on a PC with Windows XP. Following image crop, segmentation and 3D reconstruction, we got the 3D images and the video clips. According to the displays which were confirmed by latter intraoperative findings, eight donors had single renal vessels, one had a left accessory renal artery and one had a right accessory renal artery. This project offered a new approach to evaluate the renal vessel anatomy in living donor kidney transplantation, and it was favorable for accuracy and popularizing.     

Study on CuO–BaTiO3 semiconductor CO2 sensor

The prototype of a CO₂ sensor made of CuO–BaTiO₃, which has capacitance sensitive effect, is designed based on the pn heterojunctions of CuO and BaTiO₃ semiconductors. The preparation of BaTiO₃ semiconductor powders is pointed out, using the coprecipitation and semiconducting techniques. The characteristic quantities relating to the capacitance sensitive effect of the sensor are studied systematically with the aid of a gas tester. A reasonable mechanism of the sensor is proposed.     

水和甲醇存在下MAMS的消失反应动力学研究

通过实验研究了甲基丙烯酰胺硫酸盐（ＭＡＭＳ）与甲醇、水进行反应的动力学，并对该反应的机理进行了探讨。     

Study of partial discharge characteristics at repetitive square voltages based on UHF method

Due to overvoltage produced by inverter output,inverter-fed motor insulation systems often experience fast electrical aging process,especially when partial discharge(PD) is incepted.Before putting into use,the PD detection should be performed on inverter-fed motors at repetitive square voltages to avoid the PD caused insulation deterioration when the motors are collected to inverters having specific characteristics.However,unlike PD tests at AC/DC voltages proposed in IEC 60270,the PD detection at repetitive square voltages is much more complex because of serious interference generated by impulse generator.To solve the problem,ultra-high frequency(UHF) method seems recommendable for its preferable signal-to-noise ratio(SNR).The chief aim of this study is to investigate PD pulse and statistical characteristics of turn-to-turn insulation for inverter-fed traction motors.A square-shaped Archimedes antenna,specially designed for the PD detection at repetitive square voltages of fast rise times,was used to perform PD tests on turn-to-turn insulation models.Time and frequency analysis results indicate that energy component of generator disturbance and PD pulses are mainly distributed in the 0-0.5 GHz and 0.6-1.5 GHz range,respectively.Based on the results,suitable filter was designed for power disturbance suppression.Additionally,resorting to the sensor unit(i.e.antenna and filter) and the PD test system,the PD statistical features at square voltages of different frequencies were obtained.Experimental results show that higher frequency will give rise,statistically,to PD of lower magnitudes distributing at smaller phases.A reasonable interpretation of this phenomenon was presented.Lastly,according to the PD statistical features,some suggestions for the PD detection system design,generator parameter optimization and the PD pulse extracting were given.The results of this work would be beneficial to the increase of the sensitivity when performing the PD detection on insulation systems for inverter-fed motors at repetitive square voltages and thus,improving the reliability of inverter-fed motors.