An algorithm to build convex hulls for 3‐D objects

Abstract

In this paper, a new algorithm based on the Quickhull algorithm is proposed to find convex hulls for 3‐D objects using neighbor trees. The neighbor tree is the data structure by which all visible facets to the selected furthest outer point can be found. The neighboring sequence of ridges on the outer boundary of all visible facets also can be found directly from the neighbor tree. This new algorithm is twice as efficient as Barber's algorithm.     

Geometry of the minimum zone flatness functional: planar and spatial case

The zone straightness and flatness functional is constructed from the definition of the measure. The geometry of the straightness functional is illustrated in the plane, and in three dimensions, a novel means to visually represent flatness is described using the zone separation body. The zone separation body is a new construction that is uniquely associated with every measurement dataset and can be used to represent the flatness functional visually.     

Study of a stochastic model of the“dangling spider” problem with an infinite previous history and poisson switchings

To study the stability of the stochastic“dangling spider” model, the second Lyapunov method is substantiated for stochastic functional differential equations with the entire previous history. Translated from Kibernetika i Sistemnyi Analiz, No. 4, pp. 79–105, July–August, 2000.     

A recurrent stochastic binary network

Stochastic neural networks are usually built by introducing random fluctuations into the network. A natural method is to use stochastic connections rather than stochastic activation functions. We propose a new model in which each neuron has very simple functionality but all the connections are stochastic. It is shown that the stationary distribution of the network uniquely exists and it is approxi-mately a Boltzmann-Gibbs distribution. The relationship between the model and the Markov random field is discussed. New techniques to implement simulated annealing and Boltzmann learning are pro-posed. Simulation results on the graph bisection problem and image recognition show that the network is powerful enough to solve real world problems.     

也门71区块地震资料采集方法

也门71区块地表及地下地质条件异常复杂，激发接收条件差，原始资料信噪比低，静校正问题突出，资料成像困难，尤其是山地资料更是如此。特殊的地震地质条件，给地震采集带来施工和技术上的困难。为此，通过分析工区地震地质条件及以往资料质量等，对71区块地震资料采集方法进行了研究，通过优选观测系统、激发因素，采用混合震源采集、弯直线施工，地震资料品质大幅提高，该项目的成功经验也可为类似条件区的地震勘探提供借鉴。     

Existence of the l-th moment of a solution to a stochastic functional-differential equation with the entire prehistory

The definition of a strong solution to a stochastic differential-functional equation with the entire prehistory is given, and basic inequalities required for obtaining existence and uniqueness theorems are proved. Global existence and uniqueness theorems are proved. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 4, pp. 142–151, July–August 2008.     

用ATUOLISP构建的射影平面解析刀具角度

提出了用ATUOLISP构建射影平基本思想和方法；编制了射影平面的构建程序；用实例说明该软件在刀具角度解析中的应用。     

Simultaneous ℋ︁2/ℋ︁∞ control of uncertain jump systems with functional time‐delays

This paper presents new results pertaining to the control design of a class of linear uncertain systems with Markovian jump parameters. An integral part of the system dynamics is a delayed state in which the time‐delays are mode dependent. The jumping parameters are modelled as a continuous‐time, discrete‐state Markov process and the uncertainties are norm‐bounded. We construct an appropriate Lyapunov–Krasovskii functional and design a simultaneous ℋ︁₂/ℋ︁_∞ controller which minimizes a quadratic ℋ︁₂ performance measure while satisfying a prescribed ℋ︁_∞‐norm bound on the closed‐loop system. It is established that sufficient conditions for the existence of the simultaneous ℋ︁₂/ℋ︁_∞ controller and the associated performance upper bound are cast in the form of linear matrix inequalities. Simulation results are provided and extension to the case where the jumping rates are subject to uncertainties is presented. Copyright © 2007 John Wiley & Sons, Ltd.     

大跨度结构随机脉动风场的快速模拟方法

针对传统谐波合成法计算量巨大、内存耗费多的缺点,研究了空间各点的分解功率谱密度函数曲线随频率变化的特点。在此基础上,提出采用三次均匀B样条插值方法来拟合分解谱密度函数曲线,引入矩阵Cholesky分解的优化递归算法来加速矩阵分解速度,同时利用FFT技术来减少谐波项合成所需要的时间。经过上述的改进,可以大大提高双索引频率下谐波合成法的计算效率。最后利用两个算例表明,这种方法可以高效、准确地模拟出适合大跨度结构的随机脉动风场。     

Hierarchical stochastic production planning for flexible automation workshops

This paper presents the hierarchical stochastic production planning (HSPP) problem for flexible automation workshops (FAWs) in agile manufacturing environments, which is a multiple-period multiple-product problem with random material supply, demands, capacities, processing times, rework and waste products. To solve the HSPP problem, a mathematical model is built up first. Then, an algorithm for HSPP is deduced in detail by using a stochastic interaction/prediction approach. The corresponding software package named as stochastic interaction/prediction algorithm (SIPA) has been developed and is presented in this paper, through which examples of HSPP have been studied, and which show that the algorithm can optimally decompose medium-term random product demand plans of an FAW into short-term stochastic production plans to be executed by FMSs in the FAW. Finally, the application of the algorithm is presented in detail through one of those examples.