基于协同多目标算法的多机器人路径规划

多机器人路径规划是群体机器人协同工作的前提,其特点是在防碰撞与避障的前提下追求多方面资源的最小消耗.针对这一特点,提出协同非支配排序遗传算法,解决具有多个优化目标的多机器人路径规划问题;运用改进的多目标优化算法,克服多目标优化取权值的不足,同时考虑机器人能源与时间两大资源,以多机器人的路径总长度、总平滑度、总耗时为规划目标.同时引入合作型协同算法框架,将难以求解的多变量问题分组求解.每个机器人的路径视为子种群,子种群通过带精英策略的非支配排序遗传算法,进化并筛选出子种群的部分进入协同进化,每次迭代更新外部的精英解集,最终生成一组非支配路径解.仿真结果表明,在栅格地图环境下,本文算法可有效实现多移动机器人的多优化目标路径规划.     

基于协同进化的混合变量多目标粒子群优化算法求解无人机协同多任务分配问题

无人机多机协同控制系统近年来已被广泛地应用在军事打击、海洋监测、陆地航拍和灾情探测等领域.针对无人机协同多任务分配问题,为了更加准确地描述无人机协同多任务分配场景,本文考虑实际应用场景下的多种复杂约束,并以无人机飞行总航程最少和任务完成时间最短为优化目标,构建了混合变量多约束的无人机协同多任务分配问题模型M-CMTAP.为了高效求解上述模型,本文提出一种基于协同进化的混合变量多目标粒子群优化算法C-MOPSO.C-MOPSO采用基于任务分配和路径规划的编码方法表示无人机的任务分配结果和路径规划结果及基于约束处理的可行解初始化方法生成可行粒子;同时利用基于结构学习的重组策略对粒子进行更新以提高种群的多样性和收敛性;并引入协同进化策略在两个子种群之间进行合作进化以提高算法的搜索效率.根据无人机和目标的分布状态设计4个代表性的测试实例并验证算法性能,实验结果表明,与其他采用协同进化策略的算法相比,所提算法在解的收敛性和解集多样性上均具有显著的性能优势.     

多层级设施选址-路径规划问题建模及算法

基于有向图对物流网络多层级设施选址-路径规划问题,建立混合整数规划数学模型,提出量子进化算法与遗传算法协同的双智能算法集成求解方案.量子进化算法解决设施选址和设施分配,遗传算法进行路径规划,并提出可达配送区域的搜索策略和路径长度为权重的设施分配优化策略以提高算法效率.实例测试表明,所提出的数学模型和组合智能算法是可行而有效的,可为多层级设施选址-路径规划问题提供理论与方法指导.     

水下机器人最优逃生线路规划研究与仿真

水下机器人最优逃生路线规划方法在海洋资源探测方面发挥巨大作用;水下环境较为复杂,机器人在逃生过程中规划逃生路线需要考虑复杂的水下环境,建立过多的约束条件;传统的机器人路径规划模型应用到水下时,会导致建模较慢,规划耗时;为了避免上述缺陷,提出基于贪婪遗传算法的水下机器人最优逃生线路规划方法;将自适应遗传算法与贪婪算法相结合,针对水下机器人最优逃生路线规划问题求解,获取最合理的逃生线路,保证水下机器人的安全运行;实验结果表明,利用改进算法进行水下机器人最优逃生路线规划,能够在大量的逃生路线中选取满足逃生约束条件的最优路线,缩短逃生时间,保证逃生效率,最终保证水下机器人的安全逃生。     

基于改进粒子群算法的机器人路径规划方法

提出一种基于粒子群算法的机器人路径规划方法.将路径规划看作一个带约束的优化问题,约束条件为路径不能经过障碍物,优化目标为整个路径的长度最短.机器人工作空间中的障碍物描述为多边型,对障碍物的顶点进行编号.利用粒子群算法进行路径规划,每一个粒子定义为一个由零或障碍物顶点编号组成的集合,在粒子的迭代过程中考虑约束条件,惯性权重随迭代次数动态改变,使算法既有全局搜索能力也有较强的局部搜索能力.仿真结果表明该方法的正确性和有效性.     

基于蚁群模拟退火算法的水下机器人路径规划

全局路径规划是水下机器人(AUV)研究领域的重要课题之一,文中研究已知障碍物环境条件下的水下机器人路径规划问题;提出一种分布路径规划方法,首先建立移动机器人路径规划的数学模型,介绍了蚁群算法、模拟退火算法的原理,然后考虑到蚁群算法搜索时间较长,易出现停滞现象的缺点,提出蚁群模拟退火算法来解决大范围海洋复杂环境下水下机器人的路径规划问题;通过仿真实验,表明所提算法有效,并且计算简单、收敛速度快,能够满足水下机器人导航的要求.     

移动机器人的路径规划算法与仿真

研究移动机器人全局路径优化的问题,由于机器人路径随机性强,空间大,存在冗余路径,影响规划速度.传统的进化算法存在着早熟的缺点而得不到最优路径.为了克服传统算法的缺点,提高进化算法的进化速度和精确性,将云理论和粗糙集相结合应用于机器人路径规划,以提高机器人路径规划的效率.仿真由栅格法描述环境随机生成初始路径群,首先利用粗糙集训练得出一系列可行路径的集合,然后利用云进化方法对种群优化,最终得最优行走路线.仿真结果验证改进算法在收敛速度和搜索质量上都有明显的改善.     

基于改进的樽海鞘群算法求解机器人路径规划问题

为了探索出更好解决机器人路径规划问题的方法,提出一种差异演化的寄生樽海鞘群算法.首先在领导者位置更新公式中加入对应的上一代领导者位置信息,加强全局搜索的充分性,同时引入自适应惯性权重,更好平衡领导者在不同进化阶段对于广度和深度搜索的不同需求,提高寻优精度.然后在算法结构中引入具有不同演化策略和寄生行为机制的寄生-宿主双种群及宿主群劣汰思想,增加种群的多样性,提高算法跳出局部极值的能力.理论分析证明了改进算法的时间复杂度与基本算法相同,6种对比算法在10个不同特征的标准测试函数上进行仿真对比测试,实验结果表明：该算法的寻优精度、收敛性能均有显著提高和改善.最后将改进算法与三次埃尔米特插值相结合,以路径上的节点组合为基础定义算法中个体位置的编码方式,以绕开障碍、最短路径为目标构造了适应度函数和约束条件,求解机器人路径规划问题.在不同复杂程度的障碍物场景和不同插值方法下进行的算例求解结果显示,该算法寻优结果的最佳值、平均值和方差整体上明显优于其他5种性能优越的代表性对比算法,也验证了融合埃尔米特插值方法对于求解机器人路径规划问题的优越性和有效性.     

多地貌环境下的移动机器人路径规划研究

针对多地貌环境下的移动机器人路径规划问题,建立多目标优化模型,并采用微粒群算法解决该问题.首先,采用区域权值表示机器人在各种地形下的通行困难度;然后,结合局部优化准则计算机器人的通行时间,通过计算机器人与危险源之间覆盖的面积来衡量路径的危险程度,并将上述问题转化为两目标优化问题;最后,采用多目标微粒群优化算法优化上述问题.仿真结果表明了所提出方法的有效性.     

人工蜂群算法在移动机器人路径规划中的应用

研究机器人路径规划优化问题,机器人工作环境复杂,运动路径上存在许多障碍物.针对提高机器人安全导航性能问题,传统群智能算法存在早熟、搜索效率低等难题,难以获得全局最优路径.为了获得最优机器人运动路径,避免碰撞的发生,提出了一种人工蜂群算法的机器人路径规划方法.首先采用栅格法对机器人工作环境进行建模,然后机器人路径规划目标点作为蜜源,最后蜂群之间信息交换、协作搜索最优机器人运动路径.结果表明,人工蜂群算法解决了传统群智能算法存在的难题,加快了机器人路径规划求解速度,以较短时间找到最短机器人运动路径.     

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。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

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。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.