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.     

一种无人机三维航迹规划算法研究

在研究无人机三维航迹规划问题时,针对基于传统人工蜂群算法易陷入局部最优值、后期收敛速度变慢、寻优效率低的问题,提出了一种改进人工蜂群算法的无人机航迹规划方法。首先,在建立包括经纬度、海拔高度信息的三维飞行区域模型后,加入了地形约束模型,并引入新的综合航迹代价评价方式。然后,在算法中引入自适应搜索策略、新型概率选择策略与Logistic混沌搜索算子来增强其对原始信息的开采能力,提高其收敛速度以及加强其鲁棒性。最后,通过三维航迹规划仿真和面对突发威胁的局部航迹再规划仿真对所提算法的有效性进行了验证。结果表明,改进后的算法提高了全局收敛能力,在收敛速度和精度上优于遗传算法和传统人工蜂群算法,适合用来解决无人机的三维航迹规划问题。     

基于组合算法的地磁匹配导航航迹规划

研究无人机地磁匹配导航问题,为优化航迹规划,根据地磁匹配导航的特点,针对无人机航迹规划建立了特有的航迹规划模型,并提出利用组合算法对无人机的航迹进行规划.设定地磁基准图中无人机必须经过的航迹点,利用Dijkstra算法求得一条从起始点到目标点的粗选航迹,然后考虑威胁在内的各种代价应用改进“编码”的粒子群算法对粗选航迹进行优化.仿真结果表明组合算法能够克服传统算法易陷入局部最优的缺陷,大大提高了全局搜索能力,验证了组合地磁匹配导航航迹规划的有效可行性.     

无人机三维实时航迹规划

无人机航迹规划是无人机任务规划中最重要也是最复杂的环节,针对基本粒子群航迹规划算法后期容易陷入局部最优解、算法容易“早熟”、规划出的航迹精度不高等问题,提出了一种以并行方式进行的双种群粒子群航迹规划算法;双种群粒子群算法由两个向相反方向搜索的种群构成,这两个种群协同优化,扩展了搜索范围,克服了基本粒子群算法后期容易陷入局部最优解的问题,提高了航迹的精度;如果无人机在飞行过程中检测到突发威胁,则寻找邻近航迹点作为实时重规划点,规划其到目标点的航迹;通过仿真验证了算法的有效性,并满足了实时性的要求。     

实况气象资料与遗传蚁群算法相结合的航迹规划研究

利用国家气象中心提供的T106实况数值预报产品,采用预报指数模式计算飞机积冰、颠簸等潜在威胁区域,进而建立气象威胁场;在气象威胁场基础上利用遗传蚁群算法进行航迹规划,使无人机在满足约束条件下以最小代价规避气象威胁区域;仿真结果表明,该航迹规划方法可行、高效,能够准确、快速寻优到最优航迹,具有一定的实用价值。     

基于遗传算法的无人机航路规划优化研究

研究无人机航路规划优化问题,为了提高无人机航路规划效率和精度,传统的遗传算法易陷入局部最优、收敛速度慢导致无人机航路规划效率低、寻优精度较差等问题.为解决上述问题,提出了一种基于改进遗传算法的无人机航路规划方法.改进算法前期采用了保优选择策略和改进编码方案对无人机航路进行优化,加快了搜索速度、提高规划效率,使之适应大规模威胁问题求解;后期结合无人机特点,改进交叉和变异算子,通过改进使得每轮搜索后每-软的最优航路能更好地反映求解的质量,有效地加快了收敛,保持了稳定性.最后用改进的遗传算法对无人机航路规划进行了仿真.实验结果表明,方法避免了陷入局部最优、收敛速度加快、寻优精度提高,并缩短了搜索时间,航路规划效率明显提高.提出的算法可以引申应用于类似情况下的路线规划问题,具有-定的推广意义.     

巡航导弹参考航迹规划算法研究

为了提高巡航导弹的生存能力和杀伤概率,预先规划参考飞行航迹是一个重要的方法.由程序生成规划用数字地图,根据遗传算法的基本思想,采用改进的编码机制对巡航导弹在威胁已知的模拟数字地图上的飞行航迹进行整体规划,航迹种群随机生成,用加入各种威胁和约束条件影响的适应值函数对个体进行评价,通过选择交叉变芹算了使种群进化,最后所得到适应值最高的航迹个体即可作为导掸的参考飞行航迹.通过编程仿真试验,所得参考航迹可以有效的实现地形跟踪、地形威胁回避.算法由于控制参数的限制,得到的最优路径是次优化的;遗传算法的初始种群及控制参数的确定足改善算法寻优性能的主要因素.     

基于改进蚁群算法的无人机动态航路规划

研究无人机航路规划,针对基本蚁群算法易于陷入局部最优、规划航路耗时长的问题,对基本蚁群算法进行了改进;引入航路点的动态自适应选择策略和信息素挥发因子动态自适应调整准则,有效克服了基本蚁群算法的不足,并对规划出的航路进行了平滑处理,使其更加满足无人机实际飞行需求;通过仿真分别规划出无人机在静态威胁和动态威胁中的航迹,仿真结果表明,与基本蚁群算法和遗传算法相比,改进的蚁群算法在两种飞行环境中均能规划出较优的航路。     

基于改进A~*算法的灾后井下无人机航迹规划

针对传统A~*算法应用在煤矿灾后井下环境侦测的无人机航迹规划中存在搜索点冗余、遇到突发威胁时实时性较差等问题,提出了一种逆向变权重稀疏A~*算法。根据无人机自身性能约束及灾后井下威胁模型,从目标点到起始点进行全局静态航迹规划,避免大量无效搜索;根据无人机执行任务的需要设置不同权重系数,得到侧重航程或安全的航迹;通过引入次目标点策略,仅对被突发威胁覆盖的航迹进行修正,可在短时间内有效避开突发威胁。仿真结果表明,利用该算法进行航迹规划用时较短,无人机受到的威胁较小,可有效保障航迹规划的实时性和安全性。     

多约束条件下无人机航迹规划

针对多约束条件下的无人机航迹快速规划问题,建立了导航精度约束下无人机航迹规划模型,并设计了“基于Dijkstra算法的航迹规划法”求解模型。通过校正策略优选、校正方案优选和O-D邻接矩阵处理方式,简化搜索路径,降低计算量,提高执行效率,从而实现对传统Dijkstra算法的改进。在满足导航精度约束条件的前提下,以航迹长度最短和经过校正点数量最少为研究目标进行仿真实验,并将所得结果与传统Dijkstra算法和遗传算法所得结果分别进行对比,发现此算法在精度与复杂度方面均优于传统算法和遗传算法。此结果表明,导航精度约束下无人机航迹规划模型和“基于Dijkstra算法的航迹规划法”在解决多约束下无人机航迹规划问题方面具有一定的正确性、有效性和先进性。     

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。