基于K路径算法的多无人机协同航迹规划

对于满足无人机团队中各机同时到达目标这样一个特定的协同要求,首先采用K路径算法实现了无人机的多航迹规划,然后采用速度控制和K路径算法相结合的办法实现了各无人机之间的时间协同.对整个协同航迹规划问题,采用一种分散式求解方法,把高维优化问题分解成低维、计算量小、通讯数据少的问题.     

改进量子遗传算法在无人机航迹规划中的应用

研究无人机航迹规划优化问题,有效地规避威胁,可提高无人机的生存能力.但传统量子遗传算法在航迹规划方面局部寻优精度较低、稳定性差.为解决上述问题,提出改进量子遗传算法的无人机航迹规划方法.首先上述算法采用一维编码表示航迹,并对影响有效规避威胁的适应度构造代价模型和惩罚策略;针对量子遗传算法初始种群的单一性,引入关于概率划分的小生境协同进化策略,并对各种群采用动态量子旋转角,并借鉴狼群分配原则对种群进行更新,提高收敛速度;利用精英选择运算,创建精华种群,保留父代中最佳个体.仿真结果表明,上述算法的无人机航迹规划效率高,稳定性好,能够获得平滑的低代价航迹,是一种有效可行的航迹规划算法,且具有一定的推广意义.     

针对动态目标的多无人机协同组合差分进化搜索方法

针对多无人机动态目标协同搜索问题,提出一种组合差分进化无人机协同搜索航迹规划方法.建立动态目标协同搜索环境信息图模型及无人机运动模型.基于改进差分蝙蝠算法和自适应差分进化算法,设计基于种群数量自适应分配的组合框架,将差分进化算法中的变异、交叉和选择机制引入蝙蝠算法,构建组合差分进化算法的协同搜索算法,并对无人机动态目标协同搜索的航迹进行优化.针对待搜索目标轨迹随机多变且具有规避侦察特性的现实场景,建立可回访数字信息图和自适应目标搜索增益函数,从而提高无人机对动态目标的捕获能力.最后,通过仿真结果验证所提出的无人机动态目标协同搜索算法的有效性.     

基于集成约束无人机两步制航迹规划方法

无人机航迹规划是一个富含地形威胁、雷达威胁和自身可飞性等多约束的优化问题.采用两步制的规划框架,提出一种基于集成约束的无人机航迹规划方法.规划第1阶段采用基于多种群策略的差分进化优化方法,规划第2阶段采用海洋捕食者算法的Lévy运动优化;集成约束机制在搜索过程中动态更新约束策略来补偿可行解数量骤减,抑制搜索停滞.与典型算法和约束处理策略进行对比,实验结果表明,所提出无人机航迹规划方法收敛性好、稳定性强,能够有效地求解复杂多约束无人机航迹规划问题.     

多无人机模糊多目标分布式地面目标协同追踪

针对城市环境中多约束条件下多无人机协同追踪地面目标问题,综合考虑具有不同重要性等级的多个优化目标,提出了一种基于分布式预测控制的模糊多目标航迹规划方法.首先,考虑城市环境中建筑物对无人机视线遮挡、无人机和传感器能量消耗等因素,分别采用目标覆盖度、控制输入代价和开关量形式传感器能耗等为目标函数,将多无人机协同追踪航迹规划转化为多目标优化问题;然后,基于分布式预测控制框架,利用每架无人机未来有限时域内的预测状态,构建多无人机之间的避碰约束,并结合最小转弯半径等约束,形成分布式协同航迹规划模型;最后,针对多个优化目标的不同重要性等级要求,利用模糊满意优化思想将目标模糊化,并根据更重要目标具有更重要满意度的原则,将优先等级表示为松弛满意度序,通过在线求解得到有限时域内每架无人机的局部航迹;与传统多目标加权算法仿真结果对比,验证了所提方法的有效性,充分说明了该方法能够获得同时满足目标优化和重要性等级要求的最优航迹.     

基于生物地理学优化的多UCAV协同航迹规划

研究多无人机协同路径规划问题,为了获取从起始点到达目标点,能够避开各种阻碍的最优运动路径,提出了一种基于BBO的多UCAV协同航迹规划方法.通过对地形环境、航迹表示方式进行描述,将生物地理学优化算法运用于多UCAV协同航迹规划,对约束条件及威胁进行分析,建立了UCAV航迹规划模型及多UCAV协同航迹规划模型;对BBO算法适宜度向量编码及迁徙模型进行了分析,设计了相应的优化算子;最后,构建了多UCAV协同航迹规划的求解框架,并结合BBO算法开展了相应的仿真.仿真结果表明,改进方法较好地实现了多UCAV协同航迹规划的优化.     

基于高维多目标优化的多无人机协同航迹规划

随着无人机应用领域的增多,多无人机协同航迹规划问题变得愈发重要.然而,现存的多无人机协同航迹规划问题大多将多个目标加权转换为单目标问题进行优化,为减少多目标加权的主观性,本文提出一种基于高维多目标优化的多无人机协同航迹规划模型,此模型可以同时优化多无人机航迹距离代价、多无人机航迹威胁代价、多无人机航迹能耗代价,以及多无...     

关于无人机飞行航迹跟踪优化控制研究北大核心CSCD

研究无人机任务规划中的飞行航迹跟踪优化控制。为克服传统航迹规划算法仅使用航迹关键点难以满足无人机执行任务对航迹跟踪的要求,提出了一种用C^2样条算法融合的无人机三维航迹跟踪优化控制方法,解决了不同航段中无人机的可飞性、边界限制、过载限制等约束。首先针对巡航段航迹采用融合算法中的3D样条优化生成具有时效性的光滑航迹曲线。然后针对任务段航迹采用融合算法中的4D样条优化进一步生成能控制航迹关键点速度的航迹曲线,完成整条航迹的跟踪优化。仿真结果表明,关于C^2样条算法融合的无人机三维航迹优化方法能有效地优化出无人机的实际飞行轨迹,有助于无人机的航迹跟踪控制。能够满足任务规划中无人机对航迹跟踪优化控制的高精度要求,为任务执行提供良好航迹条件。     

基于改进约束差分进化算法的动态航迹规划

为解决三维复杂环境下无人机动态航迹规划问题,提出一种基于改进约束差分进化算法的动态航迹规划方法,以满足对实时性及动态搜索精度的要求.首先,根据无人机航迹规划特点将其描述为包括飞行约束及威胁约束在内的约束优化问题,并构造目标代价函数和约束限制函数;其次,将广义反向学习和自适应排序变异操作引入到约束差分进化算法中,以提高算法的多样性、收敛速度和寻优精度;最后,利用自适应权衡模型对各状态下的约束限制进行处理,充分利用“精英”个体信息,实现对目标适应值的合理转换.通过仿真实验以及与3种先进约束差分进化算法比较表明:所提方法能够有效实现静态及动态威胁回避,规划出安全适航的飞行路径,实现地形跟随;相较于其他3种算法,所提方法具有寻优性能好、鲁棒性强、收敛速度快和可靠性高等优势.     

双机协同交叉定位的三维航迹规划

面向双机协同交叉定位任务,以提高测向定位精度为目的,解决无人机的航迹规划问题。通过分析双机交叉定位的圆概率误差和无人机的动力学约束,建立双机交叉定位的三维航迹规划模型,引入带约束条件的粒子群优化算法,动态规划无人机的航迹,以持续提高测向定位精度,实现无人机的自动化控制。仿真结果表明:粒子群优化算法能有效规划出无人机的航迹,持续提高测向定位精度,算法时效性高,有一定的实际应用价值。     

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。     

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.