一种改进的交错脉冲解速度模糊方法

研究了脉冲多普勒气象雷达中用于解速度模糊的交错脉冲方法，理论分析了时域脉冲对处理中速度估计公式的局限性，同时对该公式进行了修正。仿真结果表明，改进的交错脉冲方法具有更好的解速度模糊性能，而且易于实时处理。     

Education-driven research in CAD

We argue for a new research category, named education-driven research (EDR), which fills the gap between traditional field-specific research that is not concerned with educational objectives and research in education that focuses on fundamental teaching and learning principles and possibly on their customization to broad areas (such as mathematics or physics), but not to specific disciplines (such as CAD). The objective of EDR is to simplify the formulation of the underlying theoretical foundations and of specific tools and solutions in a specialized domain, so as to make them easy to understand and internalize. As such, EDR is a difficult and genuine research activity, which requires a deep understanding of the specific field and can rarely be carried out by generalists with primary expertise in broad education principles. We illustrate the concept of EDR with three examples in CAD: (1) the Split and Tweak subdivisions of a polygon and its use for generating curves, surfaces, and animations; (2) the construction of a topological partition of a plane induced by an arbitrary arrangement of edges; and (3) a romantic definition of the minimal and Hausdorff distances. These examples demonstrate the value of using analogies, of introducing evocative terminology, and of synthesizing the simplest fundamental building blocks. The intuitive understanding provided by EDR enables the students (and even the instructor) to better appreciate the limitations of a particular solution and to explore alternatives. In particular, in these examples, EDR has allowed the author to: (1) reduce the cost of evaluating a cubic B-spline curve; (2) develop a new subdivision curve that is better approximated by its control polygon than either a cubic B-spline or an interpolating 4-point subdivision curve; (3) discover how a circuit inclusion tree may be used for identifying the faces in an arrangement; and (4) rectify a common misconception about the computation of the Hausdorff error between triangle meshes. We invite the scientific community to encourage the development of EDR by publishing its results as genuine research contributions in peer-reviewed professional journals.     

3DFD Simulation of Asymmetric Wave Field by Side-wall Acoustic Tool in Open and Cased Wells

1. Introduction Side-wall acoustic logging tools, such as the Segmented Bond Tool (SBT) from Baker Atlas and the tools for open hole measurements, utilize acoustic transducers mounted on six pads to make compensated acoustic velocity and attenuation measurements which are not affected by mud weight, gas cut, fast formation effects, casing surface conditions or reasonable tool de- centralizing. Studies on the wave fields generated by these tools are very important to tool design and data int…     

多层砖砌体房屋震害分析及抗震措施

介绍了我国砖砌体房屋历年来遭受震害的程度以及砖砌体的抗震性能，针对一些震害现象，分别从建筑布置和抗震措施加强对砖砌体的抗震性能进行论述。     

钢管混凝土柱交错桁架结构水平承载性能试验

目的 研究钢管混凝土柱交错桁架结构抗侧性能.方法 对1个3层1/3缩尺的钢管混凝土柱交错桁架结构进行水平加载试验,介绍试验方案和试验过程,分析整体结构在水平荷载作用下的受力性能、破坏机理、刚度退化规律、延性以及水平荷载在桁架与柱之间的分配关系.结果 在水平荷载作用下桁架的受压斜腹杆失稳以及受拉斜腹杆拉断导致钢管混凝土柱交错桁架结构破坏;交错桁架结构具有较大的初始侧向刚度,随着水平荷载的增加,结构的刚度退化较快;结构侧向刚度下降到初始侧向刚度50%后,交错桁架结构达到承载能力极限状态.结论 桁架发生破坏,钢管混凝土柱基本完好,交错桁架采用钢管混凝土柱合理.     

基于海德平衡理论的老年人出行态度转变分析

基于海德平衡理论,探讨了老年人公交出行行为及态度改变的机理.基于老年人出行行为特性机理分析,从平衡理论的视角,构建老年人公交出行的"P-O-X"三角平衡模型,研究老年人为获得良好的公交出行体验,在态度关系链上选择比较容易改变的关系加以转换的平衡状态调整机理.以北京市南磨房周边老年人为研究对象,开展老年人公交出行行为和意愿调查,并建立老年人错峰出行意愿模型,量化分析非平衡状态与平衡状态转换过程.结果表明:69%的老年人愿意通过调整公共交通出发时刻,将不平衡状态转化成平衡状态,可为老年人出行机动性改善提供数据支持.     

基于物理模型的烟雾模拟

在分析研究流体物理特性算法基础上,提出一种新的烟雾模拟实现方法。该方法基于物理模型的求解简化方程模拟烟雾的动态变化过程。模型中采用了非粘性欧拉方程,通常它比其他用粘性Navier-Stoke方程建模的更适合用来对气体进行建模并且减少计算量。实验验证该模型还可以正确处理烟雾与移动的物体之间的相互作用。     

杭州“智慧医疗”系统功能属性用户需求研究

目的确定杭州"智慧医疗"系统用户使用现状及各版块功能属性用户需求模型。方法在综合前期现状调研获取的杭州"智慧医疗"各版块用户行为现状及焦点小组和深入访谈发掘的用户各版块需求基础之上,编制KANO问卷对31家医院455名用户进行调查。结果 (1)用户对于智慧医疗的了解度和使用频率均不高;但使用意愿较强。(2)确立了各版块的KANO属性归类,其中属于线性属性(O)的有诊间结算的支付安全性,属于魅力型(A)的有分时预约的预约便捷性和时间精确性、诊间结算的便捷性、多功能自助机的便捷性和人工指导服务、智慧医疗App的使用便捷性和功能全面性、微信平台推送内容的便民性和及时性。结论 (1)用户对智慧医疗的总体了解度和使用频率均不高,但使用意愿较强,智慧医疗系统应基于用户需求进行优化并强化宣传推广。(2)各功能属性优先顺序如下:诊间结算的支付安全性、分时预约的预约便捷度、诊间结算的便捷度、分时预约的时间精确性、多功能自助机的人工指导服务、操作便捷度、智慧医疗APP功能全面性、使用便捷度、微信平台推送内容的便民度、推送内容及时性。     

A practical approximation algorithm for the LMS line estimator

The problem of fitting a straight line to a finite collection of points in the plane is an important problem in statistical estimation. Robust estimators are widely used because of their lack of sensitivity to outlying data points. The least median-of-squares (LMS) regression line estimator is among the best known robust estimators. Given a set of n points in the plane, it is defined to be the line that minimizes the median squared residual or, more generally, the line that minimizes the residual of any given quantile q, where 0<q?1. This problem is equivalent to finding the strip defined by two parallel lines of minimum vertical separation that encloses at least half of the points.The best known exact algorithm for this problem runs in O(n²) time. We consider two types of approximations, a residual approximation, which approximates the vertical height of the strip to within a given error bound ε_r?0, and a quantile approximation, which approximates the fraction of points that lie within the strip to within a given error bound ε_q?0. We present two randomized approximation algorithms for the LMS line estimator. The first is a conceptually simple quantile approximation algorithm, which given fixed q and ε_q>0 runs in O(nlogn) time. The second is a practical algorithm, which can solve both types of approximation problems or be used as an exact algorithm. We prove that when used as a quantile approximation, this algorithm's expected running time is . We present empirical evidence that the latter algorithm is quite efficient for a wide variety of input distributions, even when used as an exact algorithm.     

弹性介质瑞雷面波交错网格有限差分法数值模拟

为了研究瑞雷面波在复杂地质条件下的传播规律和波场特征,采用交错网格高阶有限差分方法对浅层各向同性弹性介质进行了包括瑞雷面波和体波在内的全波场模拟.通过均匀半空间模型和层状介质模型的模拟,验证了含有瑞雷面波的全波场理论的正确性.