The Time-Scaled Trapezoidal Integration Rule for Discrete Fractional Order Controllers

In this paper, the time-scaled trapezoidal integration rule for discretizing fractional order controllers is discussed. This interesting proposal is used to interpret discrete fractional order control (FOC) systems as control with scaled sampling time. Based on this time-scaled version of trapezoidal integration rule, discrete FOC can be regarded as some kind of control strategy, in which strong control action is applied to the latest sampled inputs by using scaled sampling time. Namely, there are two time scalers for FOC systems: a normal time scale for ordinary feedback and a scaled one for fractional order controllers. A new realization method is also proposed for discrete fractional order controllers, which is based on the time-scaled trapezoidal integration rule. Finally, a one mass position 1/s^k control system, realized by the proposed method, is introduced to verify discrete FOC systems and their robustness against saturation non-linearity.     

K5×Sn的交叉数

By connecting the 5 vertices of K5 to other n vertices, we obtain a special family of graph denoted by Hn. This paper proves that the crossing number of Hn is Z(5, n) +2n+[n/2] 1, and the crossing number of Cartesian products of K5 with star Sn is Z(5, n) + 5n + [n/2]+1.     

Radial drawings of graphs: Geometric constraints and trade-offs

This paper studies how to compute radially layered drawings of graphs by taking into account additional geometric constraints which correspond to typical aesthetic and semantic requirements for the visualization. The following requirements are considered: vertex centrality, edge crossings, curve complexity, and radial distribution of the vertices. Trade-offs among these requirements are discussed and different linear-time drawing algorithms are presented.     

Voronoi drawings of trees

We study the problem of characterizing sets of points whose Voronoi diagrams are trees and if so, what are the combinatorial properties of these trees. The second part of the problem can be naturally turned into the following graph drawing question: Given a tree T, can one represent T so that the resulting drawing is a Voronoi diagram of some set of points? We investigate the problem both in the Euclidean and in the Manhattan metric. The major contributions of this paper are as follows.

• We characterize those trees that can be drawn as Voronoi diagrams in the Euclidean metric.

• We characterize those sets of points whose Voronoi diagrams are trees in the Manhattan metric.

• We show that the maximum vertex degree of any tree that can be drawn as a Manhattan Voronoi diagram is at most five and prove that this bound is tight.

• We characterize those binary trees that can be drawn as Manhattan Voronoi diagrams.

一种改进型PRI变换雷达信号分选技术

在对传统的脉冲重复间隔（PRI）变换法进行介绍的基础上，提出了一种改进型的PRI变换法来估计脉冲重复间隔，并给出了相应的门限设定方法，另外，文中还提出了一种适用的快速脉冲抽取算法。仿真表明，该方法对固定PRI、抖动PRI和参差PRI脉冲序列都有较好的估计效果。     

Springback compensation in deep drawing applications

This work deals with the problem of springback compensation in sheet metal forming. Satisfactory results can be achieved by performing “die compensation”: the die is modified pretending to obtain a different configuration at the end of the punch stroke, but in order that the final piece coincides with the desired one after the deformation due to springback. Empirical die compensation has nowadays been replaced by numerical simulation, but the inverse problem that needs to be solved is non-trivial since the transformation from the modified geometry of the die and the final piece obtained from it implies a very complex FEM simulation. In this work we set the whole process of springback compensation on solid physical and mathematical grounds. An optimization algorithm based on the Gauss-Newton method is proposed to deliver automatic die compensation and its performance is investigated on some test cases.     

光栅图元的交互拾取与矢量图形的光栅化

作为工程图样矢量转换过程中一个十分重要的手段,光栅图像与矢量图表的混合编辑技术越来越受到人们的重视。光栅图元的交互提以和矢量图形的光栅化过程是这一技术的核心。本文在介绍工程图样矢量转换过程的基础上,详细描述了光栅图元的交互提取和矢量图形的光栅化方法。     

基于梯形波分析信号的一种新方法

本文以电子学中的一种常见波形——梯形波为研究对象,考虑了它的主要性质,并利用双正交性质,研究了一个信号如何才能表示成梯形波形式的问题.对非正交函数的研究是信号分析理论的有益补充.     

Excel 随机抽签系统在物理实验操作考试中的应用

针对大学物理实验操作考试中实验项目的抽签问题，提出了利用Excel中的 VFP实现现场随机抽签的方式。以某次操作考试为例，详细介绍了具体的实现方法和操作，解决了传统抽签的困难、繁琐和耗时等问题，而且体现了随机抽签考试的公开、公平、公正，该方法简单实用。     

Decoupling the effects of crystallinity and orientation on the shear piezoelectricity of polylactic acid

Shear piezoelectricity has been shown to be linearly proportional to the product of polymer crystallinity and orientation. However, investigations concerning the singular and cumulative effects of these parameters are incomplete since these studies relied exclusively on using orientation to alter crystallinity. In this research, polylactic acid (PLA) samples were fabricated by a dual drawing/annealing process to expand the investigation into the relationship between crystallinity, orientation, and shear piezoelectricity. The results of this study show for the first time that PLA shear piezoelectricity possesses a stronger relationship with the product of crystallinity and orientation than either of these parameters individually. However, this research also shows that processing of PLA for shear piezoelectric applications should focus only on achieving large degrees of orientation, which will inherently lead to increases in crystallinity as well. This approach will optimize PLA's shear sensing capabilities while avoiding certain detrimental effects, specifically embrittlement and a reversal of polymer chain orientation, which can occur during annealing. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 1555–1562, 2011