产品正逆向混合建模的方法研究

为了解决常规逆向过程中由点云生成实体模型的低效和不易建模的问题,课题组采用正逆向混合建模方法完成模型重构。课题组借助Handyscan获取模型的点云数据后,利用逆向工具完成点云数据的处理,之后在Geomagic Design X环境下完成模型的重建。经精度分析,重建的模型能够达到预期建模目标,验证了由点云数据重构出实体模型的可行性,该模型可用于进一步的创新设计。正逆向混合建模的可靠性和高效性使其成为缩短产品研发周期、进行产品创新设计的有利途径。     

Y型模块化多电平变换器原理及其在中压馈线互联中的研究

针对未来配网中压馈线柔性互联的迫切需求,提出了采用Y型模块化多电平变换器(Y modular multilevel converter, Y MMC)实现柔性多状态开关功能的研究思路。首先分析其拓扑结构与工作原理,采用功率外环电流内环的双闭环控制策略,在MATLAB/Simulink平台中搭建了系统仿真模型。在10 kV中压配网环境下,仿真研究了Y MMC对有功功率和无功功率的传输性能及系统的动态响应。结果表明所搭建的系统有较好的性能,该研究为新型交 交拓扑的柔性多状态开关用于中压配网环境下的适用性提供了参考。     

小型回转点云的配准研究

针对回转半径较大的小型回转点云配准时其回转特征不明显问题,提出一种先利用最小二乘法计算出点云的拟合平面并将所有点投影到该平面上,再利用滚球算法计算该二维点云数据的边界,并对边界点云进行3次B样条拟合,最后根据B样条曲线的变化特点,找出特征点,并利用特征点进行配准。对于回转半径较大且尺寸较小的回转点云,由于其回转特性不是非常明显,因此完全依靠其回转特性进行配准,会有一定的难度,所以需要利用其他一些特征进行配准。最后通过三坐标扫描仪获取物体的外表面形状数据,然后进行配合验证,结果表明可以准确获取特征点。该方法可以有效地对小型点云进行配准。     

Estimating the Upper Support Point in Deconvolution

Abstract.  We consider estimation of the upper boundary point F ⁻¹ (1) of a distribution function F with finite upper boundary or 'frontier' in deconvolution problems, primarily focusing on deconvolution models where the noise density is decreasing on the positive halfline. Our estimates are based on the (non-parametric) maximum likelihood estimator (MLE) of F . We show that (1) is asymptotically never too small. If the convolution kernel has bounded support the estimator (1) can generally be expected to be consistent. In this case, we establish a relation between the extreme value index of F and the rate of convergence of (1) to the upper support point for the 'boxcar' deconvolution model. If the convolution density has unbounded support, (1) can be expected to overestimate the upper support point. We define consistent estimators , for appropriately chosen vanishing sequences ( β _n ) and study these in a particular case.     

A Spatio-Temporal Model for Functional Magnetic Resonance Imaging Data – with a View to Resting State Networks

Abstract.  Functional magnetic resonance imaging (fMRI) is a technique for studying the active human brain. During the fMRI experiment, a sequence of MR images is obtained, where the brain is represented as a set of voxels. The data obtained are a realization of a complex spatio-temporal process with many sources of variation, both biological and technical. We present a spatio-temporal point process model approach for fMRI data where the temporal and spatial activation are modelled simultaneously. It is possible to analyse other characteristics of the data than just the locations of active brain regions, such as the interaction between the active regions. We discuss both classical statistical inference and Bayesian inference in the model. We analyse simulated data without repeated stimuli both for location of the activated regions and for interactions between the activated regions. An example of analysis of fMRI data, using this approach, is presented.     

关于限制性手写体汉字的一种识别方法

成功地提出了关于限制性手写体汉字的一种识别方法，并在４８６ＤＸ／６６ＰＣ机上进行了模拟实验，取得了一定的效果。对于经预处理后的手写体汉字，采用结构识别法、统计决策法和模糊数学法相结合的一种方法。另外，提出了对相似文字的识别方法     

基于服务驱动假说的消费者自提包裹选择意愿研究

基于淘宝网买家样本,分析了上门投递服务缺陷、上门投递感知风险与消费者自提意愿的关系,试图在新的认知环境下重新检验服务驱动假说。研究表明,上门投递服务缺陷一方面对消费者自提意愿产生了直接的促进作用,另一方面也通过上门投递感知风险的中介效应施加了间接作用;自提感知价值既在上门投递服务缺陷与消费者自提意愿间发挥了调节作用,又对上门投递感知风险的中介作用产生了调节。根据研究结论,可推测当前阶段下服务驱动假说具有一定合理性,相关企业应当明确自提点服务定位,并且需要调整营销推广思路。     

论法国败降的转折点意义

法国败降以后 ,法西斯集团最终结成军事同盟 ,但国际反法西斯同盟也趋向形成 ;希特勒自此掉入了自掘的两线作战的陷阱。这两个方面注定了侵略与反侵略的最后结局 ,注定了希特勒最后失败的命运。因此说 ,法国败降具有转折点意义     

论何其芳现代格律诗的出发点

何其芳的"现代格律诗"提法,有两个纠缠在一起的出发点:其一它是一种很强的意识形态行为,承担了新政权在文化领域中的规训要求;其二它是一种被召唤的诗人个体行为。梳理清楚"现代格律诗"的出发点,会发现一个综合的何其芳。     

Bayesian point null hypothesis testing via the posterior likelihood ratio

This paper gives an exposition of the use of the posterior likelihood ratio for testing point null hypotheses in a fully Bayesian framework. Connections between the frequentist P-value and the posterior distribution of the likelihood ratio are used to interpret and calibrate P-values in a Bayesian context, and examples are given to show the use of simple posterior simulation methods to provide Bayesian tests of common hypotheses.