一种基于TTA算法的船用有源滤波器

船舶上变压器,变频器,同步发电机等必然会产生谐波电流,船用有源滤波器的使用可以明显改善电流波形,减小电压与电流的畸变率,提高系统功率因素.文中详细介绍了TTA算法应用于船用有源滤波器的优点与实现过程.使用PSIM仿真验证了TTA算法应用于船用有源滤波器有较好的谐波与无功补偿效果.     

一种基于偏差最大相校正的电力有源滤波器

给出了一种基于偏差最大相校正的电力有源滤波器的实现方法。根据检测部分生成的指令电流控制变流器的模式,产生相应的跟随电流。通过偏差最大相校正的滞环比较PWM方法,在对逆变器各种工作状态分析的基础上,提出了主电路的控制策略,随机PWM的产生及对直流侧电压的要求。仿真结果表明,该方法可准确地跟踪指令电流,原理清晰,控制简单,可实现动态补偿。     

谐波的危害及其抑制方法

随着工业、农业和人民生活水平的不断提高,除了需要电能成倍增长,对供电质量及供电可靠性的要求也越来越多,电力质量(PowerQuality)受到人们的日益重视. 随着我国电能质量治理工作的深入开展,基于瞬时无功功率理论的有源滤波器进行谐波治理将会有巨大的市场潜力.综合动态的谐波治理措施并同时考虑电网的无功功率补偿问题.是电力企业当前面临的一大课题.     

逆变器共电压调节器并联运行的仿真研究

本文分析了共电压调节器逆变器并联运行的系统结构和并联系统的均流原理以及环流特性,最后用saber软件对此并联系统进行了仿真分析,验证了该控制方式的可行性。     

我国电力供需平衡周期性震荡的原因及应对策略研究

本文从系统的观点出发．结合电力工业的特点,分析了影响电力供需平衡的主要影响因素及其因果关系,建立了反映电力供给需求动态变化的系统动力学模型,模拟仿真了各种调节手段的运用对电力供应需求系统的影响,并从完善规划、加强需求侧管理两方面提出抑制电力供需周期性震荡的措施与建议。该模型的建立为系统的分析电力供需的动态变化提供了一定的参考和依据。     

并联机床精度分析研究

介绍了并联机床的误差分类及特点。结合并联机构的特点,应用微分关系建立了并联6-SPS机构位姿误差分析的正解模型,给定各结构参数误差即可得出主轴端的位姿误差。应用此模型可定量分析结构误差对主轴端位姿误差的影响,为并联机床的精度综合提供了理论依据。     

基于DSP Builder的IIR数字低通滤波器的设计

数字滤波器在数字信号处理的各种应用中有着广泛的应用。数字滤波器既可以是有限长脉冲响应（FIR）滤波器也可以是无限长脉冲响应（IIR）滤波器。通过对两者特点的比较,采用DSPBuilder实现了八阶IIR语音低通数字滤波器,通过四个二阶节级联构成数字椭圆低通滤波器,滤波器在通带内波动小于0．5dB,阻带内衰减大于60dB,完成软硬件仿真与验证。结果表明。该方法简单易行,能满足设计要求。从而验证了采用DSPBuilder实现IIR滤波器设计硬件化的独特优势。     

逆变器并联运行控制策略研究

环流是影响逆变器并联运行性能的一个重要因素,本文介绍了环流产生的原因及环流反馈控制原理,并基于此原理提出了一种双逆变器并联控制策略,并通过仿真验证了所提方法有效抑制环流。     

逆变器无互联线并联运行控制方案及其改进措施

本文分析并联逆变器功率特性和下垂控制理论,提出了传统下垂控制方法。从改善系统动态性能出发,对下垂控制算法作了改进。仿真结果表明,采用该改进算法的并联控制系统稳态性能好,动态响应快,模块间的功率均分性能和环流抑制能力良好。     

巴特沃思数字滤波器的设计与仿真实现

本文介绍了IIR巴特沃思数字低通滤渡器的设计方法与步骤,并运用MATLAB实现了巴特沃思数字滤波器的设计与仿真.     

Labour Market Policies and Long-term Unemployment in a Flow Model of the Australian Labour Market

This paper develops a general equilibrium job matching model, which is used to assess the impact of active labour market policies, reductions in unemployment benefits and reductions in worker bargaining power on long-term unemployment and other key macro variables. The model is calibrated using Australian data. Simulation experiments are conducted through impulse response analysis. The simulations suggest that active labour market programs (ALMPs) targeted at the long-term unemployed have a small net impact and produce adverse spillover effects on short-term unemployment. Reducing the level of unemployment benefits relative to wages and worker bargaining power have more substantial effects on total and long-term unemployment and none of the spillover effects of ALMPs.     

基于神经网络的房地产估价模型研究及其Matlab实现

研究目的:分析人工神经网络应用于房地产估价的思路以及估价流程,采用Madab神经网络工具箱函数编程采实现基于神经网络的房地产估价模型的构建、训练与仿真.研究方法:文献资料法和案例分析法.研究结果:以训练样本为基础,建立基于神经网络的房地产估价模型,用测试样本检验,得出估价模型的精度较高.研究结论:神经网络对包含多种因素影响的房地产估价具有优势,基于神经网络的房地产估价模型具有很强的实用性和可操作性.     

生态文明建设下风、光发电生态效益模拟与评估——以甘肃省为例

在我国生态文明建设日益受到重视的背景下,文章对风、光发电的生态影响进行了整体、全面的研究。首先,构建了分析风电和光伏发电对生态系统影响的系统动力学(system dynamics,SD)模型,并提出一种改进的耦合协调度模型;然后,以甘肃省为例进行SD情景模拟;最后,评估了多政策情景下甘肃省生态系统耦合协调度。结果表明,风电技改增效和光伏发电技改增效更有利于整个生态系统的发展。通过理论分析论证了甘肃省现行风、光发电政策的科学性,并为进一步发展风、光发电从而促进生态文明建设提出建议。     

Testing commodity futures market efficiency under time-varying risk premiums and heteroscedastic prices

We propose a novel test to measure market efficiency while estimating the time-varying risk premiums of commodity futures, given that the prices are heteroscedastic. The risk premium is estimated using a state-space model with a Kalman filter modified for heteroscedasticity. Using 79 commodity futures traded on 16 exchanges during the period 2000–2014 and a Monte Carlo simulation, we demonstrate that the proposal produces robust results compared with conventional approaches. The global financial crisis has improved the efficiency and affected the trading volumes of commodity futures, but it has had no effect on the average or the volatility of risk premiums.     

A maximum likelihood approach to estimating dynamic models with unobserved independent variables

A maximum likelihood method to estimate the parameters of dynamic models containing unobserved independent variables is proposed. The approach is to maximize the likelihood of the residuals produced by the recursive Kalman filter equations applied to the model in state-space form. A simulation study is presented comparing the proposed method to the instrumental variable approach. An example using real data is given which estimates models of the Permanent-Income Hypothesis.     

电网投资决策定量分析技术与模型——基于动态规划方法的实证预测

首先介绍了1999—2007年我国电力行业投资的发展趋势,继而分析了动态规划方法的基本原理,构建了基于动态规划方法的电网投资决策分析技术与模型;最后以某电网企业为例,说明了该方法的应用策略并检验了应用效果,通过实证模拟研究给出了该电网企业的最佳投资组合策略、投资规模和投资时机。     

基于知识权力和知识交互行为的产业集群多重知识网络演化分析

针对产业集群知识网络中客观存在但却未受关注的知识权力,结合自适应知识交互行为,采用多主体建模与仿真方法,分析知识权力的动态变化导致的产业集群多重知识网络演化。结果表明:知识权力差距及知识交互行为是促使产业集群多重知识网络形成及演化的基础,产业集群多重知识网络的演化过程具有典型的阶段性特征,其网络结构呈现出网络节点密集性与稀疏性相结合、强联结与弱联结并存、度分布高度异质性的特征。利用实际产业集群网络验证仿真结果,证明了该仿真模型的可信性。     

Modelling upstream and downstream market power in bilateral oligopoly

This article develops a general model that estimates market power exertion in a bilateral market relationship for processors and retailers where each may also have market power in their primary input market and output markets, respectively. Monte Carlo experiments are used to generate industry data for market structures such as perfect competition, monopoly, monopsony, bilateral imperfect competition with an integrated processor/retailer, bilateral imperfect competition with separate processor and retailer, and bilateral imperfect competition with four adjacent upstream and downstream markets. Then, new empirical industrial organization models are estimated using the data with models that match the market structure under which the data were generated (true) and with models that reflect alternative market structures (alternative). The general model is derived using the production function approach without imposing the fixed proportion assumption. Monte Carlo simulation results indicate that the general model is preferred to alternative models that presume competitive behaviour by processors in primary input procurement and by retailers in the output market. Results indicate that less flexible models lead to biased market power estimates in the presence of market power in the corresponding input and output markets.     

财政分权、转换系数与经济增长

在古典增长模式和内生增长模式下,以往文献多是注重规模因素和供给层面对经济增长的决定作用。事实上,结构因素、需求层面和调控层面对经济增长的决定作用越来越居于主导地位。基于此,本文通过引入转换系数这个概念,构建了一个集规模因素与结构因素、供求力量与调控力量于一体的集成型经济增长模型;通过模型的模拟得出经济体系中的转换系数在现阶段对经济增速的影响最为显著;进而指出企业家是推动经济增长的中坚力量。另外,作为案例,本文综合计量和模拟等数学工具,就SARS对经济的冲击与政府抗击疫情和挽救市场进行了模拟。     

The determinants of child mortality in the Philippines: estimation of a structural model

"This paper employs a longitudinal data set from the Philippines to estimate a structural model of the determinants of infant mortality. To control for the endogeneity of some explanatory variables, a set of reduced form equations for these outcomes is estimated simultaneously with the mortality hazard. A non-parametric discrete factor method is used to control for common unobservable factors in the error terms. Birth interval and parity lose explanatory power once biological measures are considered in the model. The results indicate significant correlations across the equations' error terms. The significant effects of breastfeeding and growth on mortality are quantified in simulation experiments." The data are from a longitudinal survey conducted in metropolitan Cebu between 1983 and 1986.