基于Petri网与遗传算法的可重入生产系统调度

可重入生产系统调度问题属于NP难题,该文建立了系统的扩展Petri网模型,并且将遗传算法方法与调度规则结合起来用于解决可重入生产系统的调度问题。针对可重入生产系统生产过程的动态复杂性,首先建立了一类综合调度规则,然后提出了基于设备分组与分时段的综合规则组合的可重入生产系统调度策略,并采用遗传算法与基于Petri网模型的过程仿真相结合的方法对综合规则组合进行优化,仿真比较验证了该调度策略的有效性。     

基于神经元动态规划的可重入生产系统调度的仿真框架

提出一个基于神经元动态规划解决可重入生产系统调度问题的仿真框架．根据可重入生产系统的特点建立状态集，并将调度问题表示成相应的马尔可夫决策过程．选择合理的性能指标，采用神经元动态规划产生每一步的调度，并在仿真中优化策略．仿真算例验证了该方法的有效性，三种调度策略的结果比较表明了神经元动态规划方法的优越性．本仿真框架还可拓展至其他类型的生产调度问题．     

可重入式生产车间调度的计算机仿真与优化研究

对于冷拔钢管生产车间的可重入生产的调度问题,采用计算机仿真软件系统eM-Plant来进行仿真优化求解.首先设定工件的成组规则,简化调度问题为投料策略与派工策略,然后采用遗传算法进行调度参数优化.仿真结果的对比表明遗传算法对此类问题的求解有较强的优化性能和稳定性.     

离散事件和混杂系统的调度控制*

从系统控制的角度研究了离散事件和混杂系统的调度问题.回顾了我们以前的工作,包括拉格朗日松弛技术,分布实时set-up 调度,随机和可维修系统的调度,神经网络及其它搜索技术的调度,制造系统和库存系统的安全点策略,以及并行处理系统的一些新的启发调度规则,等等.然后介绍了可重入生产系统调度控制的一些新结果.可重入生产系统在现代VLSI制造系统中是非常重要的.建立了QBD型模型,并用Neuts的矩阵几何方法求解.用随机搜索方法解决了监测站的设置问题.数值仿真结果证明了这种方法的有效性和适应性.     

基于遗传算法的可重入半导体生产线的调度

半导体生产线的可重入性使得半导体生产车间的调度成为NP难题.基于遗传算法的调度是将遗传算法应用到半导体生产线的投料策略和调度策略上,通过合理的编码来寻找一组投料策略和调度策略的组合,来解决可重入半导体生产线的调度问题.和以往的方法不同,这种方法可以从全局上来调度半导体生产线,充分发挥出各种策略的优势.仿真结果表明这种方法对于产出量、制造周期偏差、瓶颈设备利用率等关键生产指标都有明显改善.     

可重入生产系统的平均报酬型强化学习调度

在可重入生产系统中,一个重要的问题就是对调度策略进行优化,以提高系统平均输出率.本文采用了一种平均报酬型强化学习算法来解决该问题,直接从所关心的系统品质出发,自动获得具有自适应性 的动态调度策略.仿真结果表明,其性能优于两种熟知的优先权调度策略.     

基于遗传算法的某航空发动机装配车间优化调度

航空发动机装配车间装配生产线的调度问题,是一类比较典型的混合Flowshop问题,同时还带有工件可重人等特点,这就区别于一般的Flowshop和Jobshop调度问题,因此,将可重入混合车间调度问题划为第三类调度问题。关于重入式混合车间生产调度的优化问题通常来说都是属于NP难问题。文中通过某航空发动机装配车间生产线的研究,以最小化最大完工时间为目标函数,借助随机矩阵的编码方式和改进的交叉方法与变异方法,提出了基于遗传算法的调度优化方法。最后实验结果表明,文中提出的改进算法能够有效地实现装配车间调度的优化。     

基于混合遗传算法的重入式流水线调度研究

针对可重入式生产流水线的大规模调度优化问题,提出了一种改进的混合遗传算法。在计算适应值的过程中利用信息素算法的正反馈机制,解决工件在重入环节的竞争问题。并将禁忌搜索算法中独有的记忆功能引入到遗传算法的交叉与变异的进化过程中,可以有效的避免算法早熟和迂回搜索。通过实例仿真,表明改进后的算法相比于普通的遗传算法不仅有较强的收敛性,并且具有更快的寻优功能,是解决复杂调度问题的有效算法。     

晶圆重入加工的组合设备终止暂态的调度与分析

晶圆重入是半导体组合设备加工中典型的复杂加工工艺,分析和优化暂态加工过程对于晶圆重入加工具有重要意义.为了满足加工需求和提高组合设备的加工性能,基于稳态重入加工的双臂组合设备Petri网模型和1-晶圆周期调度策略,采用虚拟晶圆的加工模式分析了系统的终止暂态过程,讨论了系统终止暂态的加工时间分布,并给出相应的解析式进行描述.利用eM-Plant仿真平台建立了重入加工的双臂组合设备终止暂态的仿真模型,并用例子验证了1-晶圆周期调度的可行性及解析式的有效性,为研究晶圆重入加工过程的优化提供了有效方法和手段.     

基于Petri网仿真的航空发动机装配车间调度

针对含有并行机器组、可进行多品种小批量生产的可重入航空发动机装配车间,其调度问题的研究属于NP难问题。文中首先采用分层有色赋时Petri网进行系统的逻辑分析;然后给出了三种调度规则:①FCFS+;②SPT+CR+返工工件优先加工;③返工工件优先加工+ATC来实现生产调度;最后采用离散事件系统仿真方法,研究了上述3种调度算法对于最小化系统总的拖期时间的性能影响。实验结果表明,第二种调度最能有效的改善系统性能。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。