经济实用的数据备份中心

在我国企业计算机信息网正在迅速建立和扩展的今天,中心计算机房运行的可靠性对企业的生产管理至关重要。虽然目前国际上针对中心服务器、中心计算机房、甚至整个机房大楼故障或瘫痪的防止,已有一些备份效果好、恢复时间短的高可用实时热备份技术,但因其投资极高(要求远程高速通讯线路、相同机型和维护费用高昂等),国内绝大多数企业难以承受。该文将就如何改善企业网核心机房的可用性和恢复问题,主要是针对防范诸如中心服务器故障、中心机房对外通讯故障、甚至整个中心机房或机房大楼的瘫痪等严重故障,采用关系数据库技术和程序实现技术,给出了一些适合国内企业的、投资少、较为经济实用的冷备份实现技术和思想。     

Calculation of first integrals of a two-dimensional ODE system near a degenerate stationary point by computer algebra tools

An autonomous system of ordinary differential equations resolved with respect to derivatives is considered. To study its local integrability in a neighborhood of a degenerate stationary point, an approach based on the power geometry method is used. In a previous work, for some two-dimensional system depending on five parameters, a complete set of conditions on these parameters that are necessary conditions of local integrability of the considered system near a strongly degenerate stationary point was found. In this work, it is shown that these conditions are sufficient for global integrability of the system, and the corresponding first integrals of motion are found by using computer algebra tools.     

Geometric non-linear analysis of channel sections under end shortening,using different versions of the finite strip method

Two finite strip methods, namely the full-energy and the semi-energy FSM, are developed for predicting the geometrically non-linear response of channel sections with simply supported ends when subjected to uniform end shortening in their plane. The developed finite strip methods are then applied to analyze the post-local-buckling behaviour of some representative channel sections. The comparison of results revealed the fact that for the channel sections under study, the full-energy finite strip method is capable of predicting results with a greater degree of accuracy than that of the results obtained by the semi-energy finite strip method. This is due to the fact that a lower level of compressional stiffness is experienced in the case of the full-energy FSM results as compared to those observed in the case of semi-energy FSM. It is however worth noting that at the expense of slightly less accurate results, the current semi-energy analysis is benefiting from considerably less computer CPU time, due to the implementation of a fairly small number of degrees of freedom, as compared to the CPU time elapsed by the computer when the full-energy method is applied. It is noted that in the current semi-energy approach only one term is utilized, whereas several terms are implemented in the formulation of the full-energy method. Therefore, it is expected that the accuracy of the semi-energy approach will improve and correspondingly the required computer CPU time will increase if more than one term is utilized in its formulation.     

一种基于变点统计分析的图像边缘检测的方法

基于统计的图像边缘检测方法是计算机视觉中边缘检测的重要方法之一。提出了一种基于非参数变点统计分析的方向性边缘检测算法,该方法可以最小化对图像数字特征的先验信息的需求。深入讨论该算法在含有高斯噪声和椒盐噪声的灰度图像处理中的一些问题,通过实验与MATLAB的经典的边缘算子sobel算子和canny算子相比较。该方法不仅能很好地检测出图像的真实边缘,而且有效地抑制了两种噪声对边缘检测的影响,取得了较好的效果。     

Enterprise Integration—Business Processes Integrated Management: a proposal for a methodology to develop Enterprise Integration Programs

An approach to develop Enterprise Integration Programs to assist enterprises in their migration path towards integration is proposed. It is called IE—GIP (Enterprise Integration—Business Processes Integrated Management, acronyms in Spanish). The topic is very important in industrial engineering nowadays because of the growing need to improve existing industrial systems and to organise such complex systems faster, better, and in a more systematic way. The contribution to the field of Enterprise Integration is mostly a methodological one. More specifically, it is based on the integration of Purdue Enterprise Reference Architecture (PERA) and Open System Architecture for Computer Integrated Manufacturing (CIMOSA) principles to propose an integration approach for industrial enterprises. Starting from existing leading proposals (CIMOSA, PERA, GERAM), a methodology has been defined and some extension to an architecture and supporting computer tools are discussed. The proposal covers the life cycle of an Enterprise Integration Program in a top-down approach. The approach is centred on the business process concept, but is based on a vision/process/people/technology view of the enterprise. The methodology divides the work into two major phases before system construction: master planning and CIM programme development. The method adapts the system life cycle of PERA but uses, whenever possible, the CIMOSA architecture with its business process approach. New CIMOSA-like constructs are introduced to be used in activities along with the methodology when necessary. To support the modelling phases of the proposal and to provide guidance to users of the methodology, computer supported tools have been developed in the course of this work.     

Parallel Delaunay triangulation in E3: make it simple

The randomized incremental insertion algorithm of Delaunay triangulation in E³ is very popular due to its simplicity and stability. This paper describes a new parallel algorithm based on this approach. The goals of the proposed parallel solution are not only to make it efficient but also to make it simple. The algorithm is intended for computer architectures with several processors and shared memory. Several versions of the proposed method were tested on workstations with up to eight processors and on datasets of up to 200000 points with favorable results.     

一种均衡可扩展计算机体系结构分布式模拟方法

分布式并行模拟是提高体系结构模拟速度的有效技术手段之一.首先,建立了分布式并行模拟的通用性能分析模型,并对典型系统的并行加速比、并行效率等性质进行了理论分析,得出了一些有用的结论.在此基础上,提出了均衡可扩展分布式并行模拟方法SEDSim（scalable and evenly distributed simulation）.SEDSim 针对模拟节点负载不均衡问题,提出了开销模型指导的指令区间均衡分割和分配策略CoMEPA（cost model guided evenly partitionand allocation）;针对分布式并行模拟与非连续、任意数量抽样模拟区间的高效集成,提出了基于最小等价距离（minimum equivalent cost,简称MinEC）的指令区间分配策略MinEC.基于sim-outorder 实现了SEDSim,采用SPECCPU2000 中的部分程序对其速度和精度进行了测试,理论分析和测试结果均表明了SEDSim 的优势：相对于常用的方法或策略,CoMEPA 和MinEC 分别能够获得多达约1.6 倍和1.4 倍的性能提升.     

B3样条曲线曲面拟合法及其在拱坝形体设计中的应用

本文提出一种基于Ｂ３样条的自由曲线,曲面拟合方法,该方法除具有Ｂ样条拟合的主要优点外还具拟合曲线,曲面,通过所有型值点的特点,结合拱坝形体设计实例,说明了此方法的正确性和实用性     

The geometric correction of SAR imagery for the analysis of lineaments

The geometric correction of SAR images is required for many applications that entail the merging of SAR images with other data sources. One example of such applications is the mapping of geological features from SAR images. An accurate model-based geometric correction is computer and labour intensive. When a large number of images are used, this task can be prohibitive and it is then quicker to use an empirical method. This approach has been compared to the model approach and the reported results are conflicting. In some studies it has been argued that the empirical method can produce accurate geocorrection in areas of limited relief. In other studies, however, the positional accuracy using that method has been found to be unacceptable. In this Letter it is argued that in some applications, positional accuracy may not be of utmost importance and that more relevant measures such as the accuracy of orientation should be used. A geometrical method is designed to investigate the bias in orientation when an empirical method is used.     

内存泄漏的动态跟踪分析

内存泄漏是软件开发中的一个难以定位和修正的严重错误。在大多数情况下,动态内存的有效域虽未明确写出,但仍是程序的局部;且程序动态运行的轨迹在一定程度上反映程序的静态性质。基于以上观察,开发了在面向函数定位框架中嵌入动态分析的内存泄漏监测新方法。新方法中,先建立程序的函数动态调用树,其中包含程序分配释放内存的信息,再在调用树中总结程序的静态性质,为内存泄漏定位提供有价值的信息。该文用两个实例展示这个方法的有效性。     

Celtic knotwork. 1 [graphic technique]

Celtic knotwork is a beautiful form of ornament. Creating a pleasing design is a matter of aesthetics, but the mechanics of the process fit naturally into the framework of a computer program. I describe Bain's construction method (1951), explain how to write a program to implement it, discuss some ways to improve the output, and show some results. My approach is to use the computer to develop a sketch, which then serves as the basis for a hand drawing     

FPS游戏中基于HTN的Anytime规划器的研究

动态性和实时性电脑游戏世界的两个关键特征。Anytime规划是能够产生满足上述两个特征的行为的规划方法。分层任务网络（Hierarchical Task Network,HTN）是表示分层规划的一种形式,它非常适合于表达电脑游戏中非玩家角色（non-player character,NPC）复杂的目标。以著名的第一人称射击（First-Person Shooter,FPS）游戏虚幻竞技场2004（Unreal Tournament 2004）作为游戏平台,为NPC设计实现了一个基于HTN规划的anytime规划器,并使用遗传算法调整规划目标的优先级。该规划器可以根据环境变化随时中断规划并给出可用的规划结果,同时具有一定的适应性。实验表明它能够使NPC的行为更智能。     

一种求有限零和博弈解的仿真方法

博弈论是专门研究有利害冲突关系的数学理论,零和博弈是一类在社会竞争中适用面广泛的数学模型。解有限零和博弈问题的经典方法是线性规划方法。但它的运算复杂度随博弈参加者数量和选择战略数量的增加而急剧增加,并且编程复杂。该文所阐述的布朗方法是一种基于仿真的求解零和博弈的解法,它通过仿真具体的博弈过程来获得博弈的解。该方法的运算复杂度不会随着博弈加者数量的增加而急剧增加,克服了使用线性规划单纯型算法的缺陷。并且该方法计算步骤简单,易于编程实现,因此适用于计算机求解大规模的零和博弈问题。该文对这个算法做了具体介绍,并使用该方法求解了一个具体的博弈问题,最后根据得出的结果对布朗方法的特点进行了讨论。     

Constrained optimal estimation and control

A requirement of many multi-input multi-output control and estimation problems is a special structure of the gain matrix. This paper presents a constrained optimal method by which it is possible to constrain some elements of the gain matrix and to optimize the behaviour using the remaining parameters. Only linear constraints are considered and an algorithm based on a modified Riccati equation is obtained. The asymptotic solution for the steady state can be reduced to a sequence of classical Riccati equations by using an iterative approach. Numerical techniques have been found and computer programmes developed. Numerical examples are given.     

视频中的实时降雪与积雪模拟

雪景模拟,特别是基于视频和图像的实时模拟,在计算机动画、游戏和影视特效制作领域有着广泛的应用.但是现有雪景模拟方法中,计算机图形学方法的三维背景建模复杂,而图像处理的相关方法多没有结合背景信息.结合图形和图像的方法,提出基于深度图信息在视频或图像上模拟具有层次感的粒子系统降雪,并在背景图像上添加动态积雪的效果;为增强真实感,对雪花运动建模并实现实时风场;同时加入运动模糊、色调调整、雾气渲染等方式以改进视觉效果.实验结果证明,该方法渲染出的雪景十分真实,并且速度达到了实时要求.     

微机控制直流电机及其激光图形显示系统

直流电机的工作方式比较多,但是如何有效地把它们设计成为图形显示器件却是一个比较复杂又很实用的课题;文中研究了一个利用微机控制三种直流电机工作的激光图形显示系统;使用了三种不同类型的电机:可逆电机、伺服电机和反应式电机;设计了基于计算机控制的偏振、旋转和步进三种直流电机工作方式,分析了利用微机控制直流电机来显示激光图形的软硬件工作原理,给出了图形的几何变换算法及程序流程;最后展示了部分输出结果图,取得了较满意的效果。     

Computerized analytical solutions in dynamic programming

This paper concerns the computerized computation of analytical solutions to certain dynamic programming problems. The method is an algebraic approach as opposed to the discrete grid approximation technique typically used in dynamic programming. The algebraic approach, where applicable, has considerable computational advantages over the grid method.

The problems considered are those with additive quadratic returns, linear transitions, a single state variable, and a decision variable per stage. Both convex and nonconvex returns are allowed, as well as certain nonserial stage structures. An analytical procedure for quadratic problems and its implementation in a computer program are discussed. Comparisons between the analytical approach and grid approximation methods are made with respect to computational time and accuracy. Because of the computational attractiveness of the analytical approach, it has potential for use in approximation schemes for more general dynamic programming problems.     

Computer system architecture for laboratory automation

This paper describes the various approaches that may be taken to provide computing resources for laboratory automation. Three distinct approaches are identified, the single dedicated small computer, shared use of a larger computer, and a distributed approach in which resources are provided by a number of computers, linked together, and working in some cooperative way. The significance of the microprocessor in laboratory automation is discussed, and it is shown that it is not simply a cheap replacement of the minicomputer.     

On the nature of block-pulse operational matrices: some further results

The paper presents some further results concerning the methods of the block-pulse functions. Based on an earlier paper, it is shown, that the technique of the block-pulse operational matrices can be simplified by considering its discrete nature and connections with the well-known Z transform. This new approach results in simple recursive algebraic equations and can be used successfully for linear and non-linear, time-invariant and time-varying systems. First, the methods of the block-pulse convolution and stretch matrices are replaced with the method of the so-called ‘block-pulse transform’. Next, the same technique gives the recursive algebraic equations for the non-linear differential equations. The form of the recursive equations depends on the choice of the particular type of block-pulse integrating matrices (conventional, generalized and so on). Then, the block-pulse transform is applied for solving varying systems with and without delays. Finally, some new results concerning the block-pulse technique of the inverse Laplace transform for irrational and transcendental transfer functions are given. A new theorem of the equivalence of the two methods is derived and proved. Many illustrative examples show the superiority of the new approach, which compared with the methods of block-pulse or Walsh matrices seems to be very attractive, simple in the construction and easily used in a computer program.