基于滑模变结构的感应电动机直接转矩控制

针对感应电动机常规直接转矩控制中存在磁链、转矩脉动大,低速控制不精确等问题,在建立α-β坐标系感应电动机数学模型的基础上,提出了一种基于滑模变结构的新型直接转矩控制方法。该方法利用转速滑模变结构控制器代替常规直接转矩控制中的PI控制器,可有效减小常规直接转矩控制中的磁链和转矩脉动,增强了系统的稳定性。仿真结果证明了该方法的正确性。     

A balanced solution of a fuzzy soft set based decision making problem in medical science

The purpose of this paper is two folded. Firstly, the concept of mean potentiality approach (MPA) has been developed and an algorithm based on this new approach has been proposed to get a balanced solution of a fuzzy soft set based decision making problem. Secondly, a parameter reduction procedure based on relational algebra with the help of the balanced algorithm of mean potentiality approach has been used to reduce the choice parameter set in the parlance of fuzzy soft set theory and it is justified to the problems of diagnosis of a disease from the myriad of symptoms from medical science. Moreover the feasibility of this proposed method is demonstrated by comparing with Analytical Hierarchy Process (AHP), Naive Bayes classification method and Feng's method.     

On the sizing of a solar thermal electricity plant for multiple objectives using evolutionary optimization

Design, implementation and operation of solar thermal electricity plants are no more an academic task, rather they have become a necessity. In this paper, we work with power industries to formulate a multi-objective optimization model and attempt to solve the resulting problem using classical as well as evolutionary optimization techniques. On a set of four objectives having complex trade-offs, our proposed procedure first finds a set of trade-off solutions showing the entire range of optimal solutions. Thereafter, the evolutionary optimization procedure is combined with a multiple criterion decision making (MCDM) approach to focus on preferred regions of the trade-off frontier. Obtained solutions are compared with a classical generating method. Eventually, a decision-maker is involved in the process and a single preferred solution is obtained in a systematic manner. Starting with generating a wide spectrum of trade-off solutions to have a global understanding of feasible solutions, then concentrating on specific preferred regions for having a more detailed understanding of preferred solutions, and then zeroing on a single preferred solution with the help of a decision-maker demonstrates the use of multi-objective optimization and decision making methodologies in practice. As a by-product, useful properties among decision variables that are common to the obtained solutions are gathered as vital knowledge for the problem. The procedures used in this paper are ready to be used to other similar real-world problem solving tasks.     

浅谈软件开发过程中的方法问题

先进的制造模式要求信息集成和功能集成贯穿于产品生命周期的每一阶段,功能的集成需要软件系统的支持,从而推动先进制造模式的实现。软件开发过程是建造软件解决方案的关键要素。本文详细讨论了两类主要的过程开发方法,即面向对象方法和结构化方法。     

多阶段规划工业园区的双重功能共享储能配置

以工业园区共享储能为研究对象,提出了包含储能和不间断电源双重功能的工业园区共享储能结构框架,建立了共享储能设备容量和共享储能运营商净现值的模型,为通过优化配置共享储能设备以实现新能源出力备用和替代不间断电源提供了一种可行的路径;采用场景树表示工业园区电力负荷和光伏的随机性,建立了一个旨在使共享储能运营商经济效益最大化的多阶段随机规划模型,并采用随机对偶动态规划算法对模型进行求解;利用具体算例验证了模型的有效性。     

IS风险评估方法分类研究*

尝试分别从信息技术演化过程和驱动因素两个方面对信息系统风险评估方法(ISRAM)进行分类.首先选择信息技术和ISRAM发展的时间主线划分ISRAM,然后提取ISRAM设计实现过程中考虑的驱动因素划分ISRAM,并分别给出两种分类方法的半形式化描述;最后,分析目前ISRAM面临的挑战和未来发展趋势.     

常态化推进部队作战训练成果进课堂途径探究

为落实新时代军事教育方针为战育人要求,增强以战领教意识,不断提升军事教育实战化水平,分析了常态化推进部队作战训练成果进课堂现阶段存在的问题,从深化对常态化推进部队作战训练成果进课堂的认识、健全部队作战训练成果进课堂的途径机制和加强部队作战训练成果进课堂的转化运用三方面提出了解决问题的途径,给出了实施效果.     

Modelling of plastic flow, heat transfer and microstructural evolution during rolling of eutectoid steel rods

A study was undertaken in an attempt to quantitatively describe the rolling process of eutectoid steel rods. Finite element method was employed to model plastic flow and heat transfer in the deformed material, and heat transfer during cooling to ambient temperature. The numerical calculation gave an assessment of the strain, strain rate and temperature distributions in the work piece. This allowed the prediction of the austenite microstructure evolution during the process. Finally, the relationships describing the microstructure-mechanical properties were used to quantitatively characterize the influence of processing parameters on strength of rods after rolling.     

一种交流阻抗和弱极化相结合的腐蚀速度测量方法

提出了交流阻抗和弱极化技术相结合的腐蚀速度测量的方法，并依此研制了CMB-4510腐蚀速度测量仪.有效地解决了线性极化技术因估算塔菲尔系数所带来的理论误差，进一步消除了因介质电阻IR降的影响产生的测量误差.结果表明，CMB-4510腐蚀速度测量仪测得的几种体系的腐蚀速度、极化电阻以及介质电阻与M398所测得结果相同；测量缓蚀剂的缓蚀效果与挂片失重法的测试结果完全吻合.