汽车转向梯形断开点位置的优化设计

应用空间机构运动学的原理,采用Matlab编制转向梯形断开点的通用优化计算程序,确定汽车转向梯形断开点的最佳位置,从而将悬架导向机构与转向杆系的运动干涉减至最小,为双横臂式独立悬架转向梯形设计提供了精确适用的方法.     

Image segmentation using voronoi polygons and MCMC, with application to muscle fibre images

We investigate a Bayesian method for the segmentation of muscle fibre images. The images are reasonably well approximated by a Dirichlet tessellation, and so we use a deformable template model based on Voronoi polygons to represent the segmented image. We consider various prior distributions for the parameters and suggest an appropriate likelihood. Following the Bayesian paradigm, the mathematical form for the posterior distribution is obtained (up to an integrating constant). We introduce a Metropolis-Hastings algorithm and a reversible jump Markov chain Monte Carlo algorithm (RJMCMC) for simulation from the posterior when the number of polygons is fixed or unknown. The particular moves in the RJMCMC algorithm are birth, death and position/colour changes of the point process which determines the location of the polygons. Segmentation of the true image was carried out using the estimated posterior mode and posterior mean. A simulation study is presented which is helpful for tuning the hyperparameters and to assess the accuracy. The algorithms work well on a real image of a muscle fibre cross-section image, and an additional parameter, which models the boundaries of the muscle fibres, is included in the final model.     

Optimal on-line detection of outside observations

Suppose that a Markov process X₁,X₂,… appears consecutively. There are two random moments of time θ₁ and θ₂, independent of (X_n). The distribution of the process (X_n) changes for the first time at instant θ₁ and for the second time at instant θ₂. Our objective is to find a stopping rule based only upon the former values of (X_n) which maximizes the probability that the moment of stopping is between θ₁ and θ₂. A sufficient condition is given under which an optimal stopping time is finite. The maximal probability corresponding to the optimal rule is found.     

库存动力系统研究

文章将企业库存理论与动力系统结合起来 ,揭示了二者间的内在联系 ,建立了库存动力系统的概念和相关理论。系统研究了一、二阶库存动力系统的特点、建模与控制。结合实例对一阶系统进行了预测与调制。具有理论和实际意义     

对政府分配功能和税收分配功能的重新界定

重新界定政府分配功能应明确两点:一是政府分配功能存在于国民收入分配的全过程;二是现实中政府分配功能具有二重性,即积极作用和负面影响。重新界定税收分配功能应明确两点:一是税收分配功能存在于国民收入分配的全过程;二是税收分配功能有多种作用形式。     

理想气体直线过程中一个值得注意的问题

本文指出了理想气体系统经历负斜率直线过程时吸放热混合出现的热传递现象；导出了负斜率直线过程中系统的绝热点体积公式；纠正了含有负斜率直线过程的循环效率的错误计算。     

Countermeasures for night work performance deficits: The effect of napping or caffeine on continuous performance at night

Napping and caffeine consumption, two common strategies for improving alertness and performance on the night shift, were investigated in two separate studies. Performance was measured with a simulated assembly line task (SALT) during a single night work shift. Both strategies proved beneficial. Performance and subjective alertness were improved following either a 2.3-h evening nap or ingestion of caffeine (4 mg/kg) prior to the work shift. The effects were noted particularly at the trough of circadian alertness. Although neither napping nor caffeine countered the strong circadian influence on performance and alertness in the early morning hours, both strategies attenuated their sharp decline. Further research is required to determine the generalizability of these findings beyond a single night shift and in different populations of workers, such as older age groups, or chronic caffeine users.     

Robust Bayesian hypothesis testing in the presence of nuisance parameters

Robust Bayesian testing of point null hypotheses is considered for problems involving the presence of nuisance parameters. The robust Bayesian approach seeks answers that hold for a range of prior distributions. Three techniques for handling the nuisance parameter are studied and compared. They are (i) utilize a noninformative prior to integrate out the nuisance parameter; (ii) utilize a test statistic whose distribution does not depend on the nuisance parameter; and (iii) use a class of prior distributions for the nuisance parameter. These approaches are studied in two examples, the univariate normal model with unknown mean and variance, and a multivariate normal example.     

A three-dimensional object point process for detection of cosmic filaments

Summary.  We propose to apply an object point process to delineate filaments of the large scale structure in red shift catalogues automatically. We illustrate the feasibility of the idea on an example of the recent 2dF Galaxy Redshift Survey, describe the procedure and characterize the results.     

初始点任意优化问题的广义梯度投影法

利用广义投影与罚函数技巧和辅助规划处理带等式和不等式约束问题以及采用二阶段搜索方法，给出了一个初始点可任意的带不等式和等式约束的优化问题的广义梯度投影算法，并证明了该算法具有全局收敛性。文中削弱了文献［１］的条件，保持了它的优越性，罚参数在计算过程中自动调整且只需适当大，因此，在实际运用中不会有太大的困难。