基于改进A*算法室内移动机器人路径规划

A*算法常用于二维地图的路径规划,但是在利用其进行室内移动机器人路径规划时,存在过多的冗余点和拐点,造成了内存消耗过大和路径不平滑。针对上述问题,提出了一种改进的A*算法。结合跳跃点搜索理论,利用先验信息,用选取的关键点代替了传统A*算法中Openlist和Closelist的点,减小了计算量,提高了运算速度。运用反向搜索策略,对路径进行二次规划,删除不必要的转折点,降低了路径长度。将路径在转折点处进行动态圆平滑处理,提高了路径的平滑性。为了验证改进A*算法的性能,将其应用于不同尺寸仿真栅格环境地图和处于真实室内环境的机器人中,实验结果表明,在相同环境下,改进算法相较于传统的A*算法,在运行时间、路径长度和平滑程度上均有明显的提高。     

基于BIM的地图构建与导航研究

为了提高移动机器人在作业过程中获得现场环境地图的效率,提出了利用BIM技术建立导航地图的方式,获取IFC信息映射到二维栅格,从而快速构建地图;对于室内移动机器人在移动过程中能更快更好的到达目标点的问题,首先对传统A*算法做改进,将原有的8邻域搜索扩展为48邻域搜索,增加了搜索方向,优化了搜索角度;同时考虑了机器人的安全性,对规划路径进行了改进,使得规划的路径与障碍物保持了一定距离;其次,为了避开场地出现的动态障碍物,采用将改进的A*算法与动态窗口法融合,在保证全局路径最优的基础上,实现避障效果;通过实验仿真,表明了改进的A*算法比传统A*的算法在运行时间上快了2倍以上,路径转折点的角度差比原来减少了28%以上,路径长度上更短且不再紧贴障碍物;而融合算法比改进的A*算法在路径平滑性上有所提高,能及时避开随机障碍物,更加适用于环境变化的室内场景。     

基于人工势场的A*算法的移动机器人路径规划

为了解决传统A*算法规划路径时未考虑到障碍物分布对路径选取的影响,文中提出了一种改进的A*算法.将人工势场的思想与传统的A*算法相结合,对栅格地图中的障碍物赋予斥力场函数并计算周围栅格的斥力大小,进行路径搜索时将栅格的斥力大小引进到A*算法的评价函数当中以改进A*算法的搜索能力.通过MATLAB仿真和Turtlebot机器人的实验结果表明,与传统的A*算法相比,改进后的新算法与人工势场算法相结合,规划出了更优的路径,提高了路径规划效率,且搜索速度提高了 13.40％～29.68％,路径长度缩短了 10.56％～24.38％,路径节点数减少了 6.89％～27.27％,因此,改进的A*算法的优化效果明显,具有有效性和可行性.     

基于人工势场的A*算法的移动机器人路径规划

为了解决传统A*算法规划路径时未考虑到障碍物分布对路径选取的影响,文中提出了一种改进的A*算法.将人工势场的思想与传统的A*算法相结合,对栅格地图中的障碍物赋予斥力场函数并计算周围栅格的斥力大小,进行路径搜索时将栅格的斥力大小引进到A*算法的评价函数当中以改进A*算法的搜索能力.通过MATLAB仿真和Turtlebot机器人的实验结果表明,与传统的A*算法相比,改进后的新算法与人工势场算法相结合,规划出了更优的路径,提高了路径规划效率,且搜索速度提高了 13.40％～29.68％,路径长度缩短了 10.56％～24.38％,路径节点数减少了 6.89％～27.27％,因此,改进的A*算法的优化效果明显,具有有效性和可行性.     

基于邻域拓展的静态路径规划A*算法研究

为了解决传统的A*算法搜索自由度低,规划出的路径长度长且转角大的问题,提出了一种改进的A*算法.改进算法将传统的8邻域搜索拓展到24邻域,并利用引导向量优化邻域数量,提升搜索效率;采用路径平滑算法消除路径中的冗余节点,优化平滑路径.在不同障碍率、不同栅格地图等12种模拟场景下的100次有效实验与真实地图下的20次有效实...     

基于双向搜索改进A*算法的自动导引车路径规划

在面积比较大的或划分精细的栅格地图中进行自动导引车(AGV)行驶路径规划时,经典的A*算法搜索得到的路径往往冗余节点和转折点较多,搜索路径时间较长.为了提高A*算法的实时性,提出了一种基于双向搜索路径的A*算法.首先,对于A*算法的启发函数引入父节点和Chebyshev Distance,改进启发函数;其次,引入双向路径搜索的动态窗口,同时从路径的起点和终点搜索路径,得到一条初始路径,并论述了动态窗口的大小对于双向搜索路径的影响;最后,依据关键点搜索原理,剔除初始路径中存在的冗余节点,得到最终的搜索路径.实验证明,相较于单向改进A*算法和改进人工势场算法,双向搜索改进A*算法搜索路径耗费时间分别降低了22.9％和78.4％,路径包含节点数分别降低了82.2％和99.5％,证明了算法的有效性.     

基于双向搜索改进A*算法的自动导引车路径规划

在面积比较大的或划分精细的栅格地图中进行自动导引车(AGV)行驶路径规划时,经典的A*算法搜索得到的路径往往冗余节点和转折点较多,搜索路径时间较长.为了提高A*算法的实时性,提出了一种基于双向搜索路径的A*算法.首先,对于A*算法的启发函数引入父节点和Chebyshev Distance,改进启发函数;其次,引入双向路径搜索的动态窗口,同时从路径的起点和终点搜索路径,得到一条初始路径,并论述了动态窗口的大小对于双向搜索路径的影响;最后,依据关键点搜索原理,剔除初始路径中存在的冗余节点,得到最终的搜索路径.实验证明,相较于单向改进A*算法和改进人工势场算法,双向搜索改进A*算法搜索路径耗费时间分别降低了22.9％和78.4％,路径包含节点数分别降低了82.2％和99.5％,证明了算法的有效性.     

非结构化场景下基于改进JPS算法的移动机器人路径规划

针对移动机器人在大范围非结构化场景下的路径规划问题,在改进跳点搜索(JPS)算法的基础上结合A*搜索,提出一种基于分层栅格地图的Jump A*(JA*)路径规划算法.该算法对三维点云地图进行栅格化分层处理,将环境信息划分为结构层与非结构层,并建立搜索策略切换规则,依据图层信息使用不同的搜索策略,从而有效减少计算量.为了验证JA*算法的有效性,在图层比例不同的三维地图中进行仿真,仿真结果表明,JA*算法相比于传统的A*算法遍历节点更少,搜索效率更高;相比于双向A*算法,具有更高的鲁棒性.最后将JA*算法应用在公开数据集中,实验结果表明,JA*算法能有效解决移动机器人在大范围非结构化场景下的路径规划问题.     

单边矩形扩展A~*算法

提出了一种新的单边矩形扩展A*(REA*)算法.新算法采用受迫扩展规则,在以矩形单元探索地图的过程中,用单条公共边取代相邻矩形的2条冗余独立边,从而提高了算法效率,简化了终止条件,优化了路径质量.在无需对地图进行预处理的情况下,算法速度比传统A*算法提高1个数量级以上.算法能够保证得到栅格最优的路径点序列,且最终路径(由路径点间直线组成)总是比栅格最优路径更短.典型地图集上的实验结果表明,相比于现有REA*算法,新算法提高了对复杂地图的处理能力和算法效率上限.新算法路径长度更短,路径转折次数更少,因此路径质量更优.除了在低复杂且不开阔的地图上外,新算法平均效率也高于REA*算法.     

基于A*改进算法的四向移动机器人路径搜索研究

在由栅格法构建的环境地图中,利用A*算法进行路径搜索时存在搜索范围广、搜索速度慢、路径曲折等问题.针对栅格地图及具有四向移动机器人的特点,从搜索方向、启发函数构建、机器人加减速以及转向成本等几个方面对A*算法进行研究和改进,提出一种基于启发信息的扩展节点算法,降低偏离最佳路径节点的扩展数量.改进后的A*算法平均可降低67.1%的搜索面积、49.2%的计算时长、24.9%的路径成本及减少51.1%的转向次数,提高了路径的搜索速度和平滑度.     

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。