基于模糊RBF神经网络的柴油机电液调速控制方法

介绍了电液调速执行器的动态特性,设计了电液调速控制回路,实现了模糊RBF神经网络对柴油机油门执行器位置的控制。将一种基于模糊RBF神经网络的PID控制器应用于柴油机调速控制中,详细说明了模糊RBF神经网络控制器的设计过程,它结合了传统PID以及神经网络和模糊控制的优点,可以在线调整得到一组最优的PID控制参数。仿真结果表明该系统比传统模糊控制的响应速度快、超调小,且适应性强,具有推广价值。     

臭氧技术在柴油机中的应用

通过对柴油发动机臭氧助燃机理分析,设计了臭氧发生器,并将其用于6135型柴油发动机台架试验中。试验结果证明：臭氧参与柴油发动机的燃烧过程起到了节油和降低排放的双重效果。     

石家庄市大气颗粒物与能见度相关性研究

运用计量地理学相关分析的方法,以石家庄市2009年12月~2011年1月数据为例,研究大气颗粒物与能见度变化的相关性.研究结果显示:相对湿度与大气能见度呈显著负相关,与颗粒物质量浓度相关性较差;大气颗粒物质量浓度与能见度之间呈负相关,[0.43,0.65)μm粒径范围内二者相关性较显著.     

中国农业产出缺口测算及其价格效应研究————基于劳动力有限供给视角

城镇化和工业化吸收了大量农村剩余劳动力,导致农业生产投入要素失衡,加剧了农副产品消费需求和产出供给的矛盾,产生价格上涨压力。基于“缺口-价格”模型的实证研究显示,负向农业产出缺口对农副产品价格具有滞后1-3期的直接正效应,18个省份分地区面板回归验证了直接价格效应的存在且滞后期为3-4期;工农业产出缺口存在长期均衡关系,但短期内两者的影响弹性不显著。由此可知,农业产出缺口对通货膨胀存在直接效应和间接效应,治理通胀要从加大农业生产扶持、协调工农业生产和畅通农副产品流通渠道入手。     

Reml and best linear unbiased prediction in state space models

This article takes a hierarchical model approach to the estimation of state space models with diffuse initial conditions. An initial state is said to be diffuse when it cannot be assigned a proper prior distribution. In state space models this occurs either when fixed effects are present or when modelling nonstationarity in the state transition equation. Whereas much of the literature views diffuse states as an initialization problem, we follow the approach of Sallas and Harville (1981,1988) and incorporate diffuse initial conditions via noninformative prior distributions into hierarchical linear models. We apply existing results to derive the restricted loglike-lihood and appropriate modifications to the standard Kalman filter and smoother. Our approach results in a better understanding of De Jong's (1991) contributions. This article also shows how to adjust the standard Kalman filter, the fixed inter- val smoother and the state space model forecasting recursions, together with their mean square errors, for he presence of diffuse components. Using a hierarchical model approach it is shown that the estimates obtained are Best Linear Unbiased Predictors (BLUP).     

Non-Gaussian Ornstein–Uhlenbeck-based models and some of their uses in financial economics

Non-Gaussian processes of Ornstein–Uhlenbeck (OU) type offer the possibility of capturing important distributional deviations from Gaussianity and for flexible modelling of dependence structures. This paper develops this potential, drawing on and extending powerful results from probability theory for applications in statistical analysis. Their power is illustrated by a sustained application of OU processes within the context of finance and econometrics. We construct continuous time stochastic volatility models for financial assets where the volatility processes are superpositions of positive OU processes, and we study these models in relation to financial data and theory.     

Smoothing a Time Series by Segments of the Data Range

We consider the problem of estimating a trend with different amounts of smoothness for segments of a time series subjected to different variability regimes. We propose using an unobserved components model to consider the existence of at least two data segments. We first fix some desired percentages of smoothness for the trend segments and deduce the corresponding smoothing parameters involved. Once the size of each segment is chosen, the smoothing formulas here derived produce trend estimates for all segments with the desired smoothness as well as their corresponding estimated variances. Empirical examples from demography and economics illustrate our proposal.     

波前滤波小波函数的理论分析和构造方法

从惠更斯-菲涅耳的衍射理论出发．分析了受限孔径衍射相当于波前滤波．以夫琅和费单缝、圆孔为例．得到了小波在波前滤波时应满足的条件．并给出了满足波前滤波条件的小波的构造方法．     

用余弦调制PR－FIR方法构造M带正交小波基

离散小波变换将离散时间信号分解为一系列不同分辨率下的离散近似信号和离散细节，紧支的正交规范小波与完全重构正交镜像滤波器（ＰＲ－ＱＭＦ）相对应。在紧支正交小波基的构造条件下，利用余弦调制完全重构滤波器组的方法，实现了Ｍ带紧支正交小波基的构造，计算机模拟表明该方法非常简单、有效。