旋转式倒立摆系统控制策略研究

介绍了一种新型的旋转式倒立摆实验装置,对其系统模型进行动力学分析,建立了一个四阶状态空间方程。分别采用状态反馈和最优控制方法对其进行仿真研究,在此基础上实现倒立摆实时稳定控制。     

Optimization of threshold for local spectrum sensing with energy detector

Spectrum sensing is the first step of cognitive radio (CR). In this area, previous researches mostly consider distributed local nodes which are under identical channel conditions, hence uniform and fixed detection threshold is set with energy detector. However, the distributions of nodes in real environments are not quite the same. In this paper, the optimal threshold to minimize the total detection error over additive white Gaussion noise (AWGN) channel is derived firstly. Then the dynamic threshold scheme is proposed to reduce the average total detection error. Simulations have shown that, with this scheme, sensing performance is improved.     

A simplified differential game model for the optimal choice of tax rate

IntroductionTaxisthemainsourceofthefinancialrevenueofacountry.Itdependslargelyonthegrossnationalproduction,whichisinturndeterminedtoasignificantextentbythegrowthoffirms[1-2].So,inordertoincreasetaxrevenues,thegovernmentshouldpaysufficientattentiontothechoiceoftaxrateswhichmayaffecttheeconomicbehaviorofafirm,suchasinvestmentstrategy,capitalstructureanddividendpolicy[3-5].Therefore,itisinappropriateforthegovernmenttotakesomeofthekeyeconomicvariablesofthefirmasexogenousinalongperiod.Whenselectin…     

Does lengthening the school day increase students’ academic achievement? Results from a natural experiment in Chile

This study (an impact evaluation of the Chilean full school day program) uses difference-in-differences to estimate the effect of a large increase in instructional time on high school students’ academic achievement. The main findings are (i) the program had a positive effect on students’ achievement in both mathematics and language; (ii) the effect-size on language achievement was 0.05–0.07 standard deviations and not sensitive to control for covariates, different control groups, and historical trends; (iii) the effect on mathematics achievement was not sensitive to control for covariates, but was sensitive to use different control groups, and historical trends; the effect-size on mathematics achievement ranged from 0.00 to 0.12 standard deviations; and (iv) the program effect has been constant over time. Finally, there is evidence suggesting that the program had larger positive effects on rural students, students who attended public schools, and students situated in the upper part of the achievement distribution.     

我国农村职业教育资源配置主要问题探析

我国城乡一体化进程的不断推进对农村职业教育提出了越来越高的要求,但制约我国农村职业教育发展的关键因素是资源配置。当前,我国农村职业教育资源配置面临着资源总量不足、资源配置失衡、资源分割以及资源整合水平不高等问题。而现行财税制度、城乡二元社会结构、行政管理体制僵化以及市场机制失灵则是导致这些问题的重要原因。     

现阶段我国税制改革的思路

1994年的税制改革是一次全方位、根本性的改革,是税制发展史上的一个里程碑。但随着社会主义市场经济体制的逐渐完善,现行税制存在的问题也日益凸显,如税制结构不合理、税收负担不公平和计税基础不够宽等。结合我国现阶段税制运行的实际情况,借鉴最适课税理论的思想,坚持效率优先、兼顾公平的原则,我国应当进一步推进税制改革,即调整间接税与直接税,实现二者的合理搭配;保留差别待遇,规范税收优惠;加快费税改革,扩大计税基础。     

活性污泥法多变量最优控制的遗传算法实现

针对最优控制传统算法存在的一些问题,着重研究了采用遗传算法在限制有机物排放总量时,使污水处理运行费用最低的最优控制问题,提出了一种新的污水处理最优控制问题的计算方法,提高了计算效率.     

根平方平均的最优凸组合不等式

本文得到最大值α和最小值β,使得对所有的a,b>0,a≠b双向不等式αC(a,b)+(1-α)A(a,b)相似文献   

内蒙古通辽市科尔沁区基层卫生院卫生资源配置的公平性研究

目的通过对内蒙古通辽市科尔沁区乡镇（苏木）卫生院卫生资源配置现状与公平性分析,查找存在的问题,为和谐社会建设和政府决策提供科学依据。方法采用整群分层随机抽样的方法,对通辽市科尔沁区9个乡镇（苏木）卫生院大型仪器设备、实有床位数等进行了调查,结果均采用SPSS15.0软件建立数据库,进行统计分析,用数学软件Matlab7.0绘制Lorenz曲线并计算Gini系数值。结果 2004～2008年五年间科尔沁区乡镇（苏木）卫生院占地面积、固定资产总值、总建筑面积、大型仪器设备、实有床位数呈现较快的增长;大型仪器设备、实有床位数按人口分布、地理分布的Gini系数分别为：0.32、0.46、0.39、0.53。结论通辽市科尔沁区乡镇（苏木）卫生院规模、布局不尽合理,卫生资源拥有量较少,条件较差,床位资源无论是按人口分布,还是按地理分布的公平性较差,在一定程度上造成了看病难,服务差等问题。这些问题可以通过推进乡镇（苏木）卫生院改革,增加资金投入等途径予以解决。     

辽宁省科技资源配置现状及优化对策分析

利用2000 年到2010 年的统计数据,分析辽宁省科技资源的配置状况,认为辽宁省的科技资源在总体质 量、总体数量、增长率以及科技资源的资源共享平台等方面存在较大的问题,应该在科技资源的市场化配置模式、科 技资源的共享平台构建、构建官产学研R&D联盟等几个层面加以改进,进而促进辽宁科技水平的提升。