基于仿人发育的混合空域智能无人机 防碰撞策略研究

随着低空开放政策的实施,无人机将会脱离隔离空域,进入低空与各式各样飞行器混合进行飞行。而防碰撞能力作为无人机的关键技术,在混合空域中保持无人机安全飞行起到了至关重要的作用。通过对人的发育式学习防碰撞机理进行分析,建立了面向混合空域中密集障碍的实体模型和发育模型,最终构建了基于仿人发育的无人机防碰撞方法。仿真实验表明,提出的方法不仅使无人机可以通过学习与发育不断提高飞行安全性,而且还可以随着环境熟悉度的提升,加快无人机防碰撞行为,提高了无人机在混合空域密集障碍中的安全性与智能性。     

面向无人机自主防碰撞的认知博弈制导控制

针对非隔离空域中的无人机碰撞规避问题,提出一种基于认知博弈制导的无人机自主防碰撞方法.首先,描述了非隔离空域中无人机自主防碰撞控制问题.其次,建立了无人机与入侵机的运动学模型,并构建了无人机的认知安全域,将无人机碰撞规避问题转化为涉及两方的博弈问题.然后,提出了制导策略集的求解方法.最后,仿真结果验证了所提方法的有效性.     

无人机认知防碰撞系统安全边界研究

无人机认知防碰撞控制是借鉴人类认知智能,建立复杂动态环境无人机防碰撞控制的新思路,其认知决策的安全边界是系统设计的重要问题.本文整体考虑环境威胁与无人机的相互作用关系,建立了“认知无人机-环境系统”模型.进而定义了系统的防碰撞稳定性,并导出了认知无人机-环境系统的防碰撞稳定条件.在此基础上,通过分析防碰撞稳定的安全特征量,解算出面向动态正向碰撞的无人机认知防碰撞系统的安全边界.仿真实验分析了“云雀”无人机的安全边界特性和防碰撞控制要求,并与其他方法进行了对比.     

认知无人机–环境系统的防碰撞稳定性

借鉴人在复杂动态环境中的自主防碰撞行为,可以构建具有认知防碰撞能力的无人机.针对认知防碰撞决策的有效性问题,将认知无人机与环境的动态交互过程作为整体,通过分析认知无人机-环境系统状态的运动模式,基于混合时间集建立了认知无人机-环境系统的脉冲微分包含(IDI)模型.按照认知无人机防碰撞过程的IDI运行机理,将系统状态空间划分为三类运行域,建立了认知无人机-环境系统的防碰撞稳定性定义,进而运用IDI理论,导出了使认知无人机-环境系统防碰撞稳定的充要条件.仿真实验结果表明,导出的防碰撞稳定条件可以为无人机认知防碰撞决策的有效性提供依据.     

城市密集不规则障碍空间无人机航路规划

随着国家低空开放和民用无人机的普及,小型无人机在城市空间的使用将会越来越广泛,城市空间的密集不规则障碍环境对无人机的安全提出了严峻挑战.针对传统的全局航路规划方法在密集不规则障碍环境中容易陷入局部"死区"而导致飞行危险的问题,通过设计当前航点到无人机视界的航路代价函数,建立了局部视界范围内的最优回溯模型,提出基于局部回溯和广度优先思想相结合的综合路径规划方法.仿真对比实验表明,本文提出的航路规划方法避免了传统的全局规划方法存在的局部"死区"问题,可在密集障碍环境中为无人机规划出安全可飞的航路,使无人机能够规避任意不规则形状的危险障碍,提高了无人机在城市低空环境中飞行的安全性.     

基于威胁度评估的机器人神经动态避撞策略

针对动态环境下移动机器人的自主碰撞规避,构建了包含感知模块、威胁规避模块和目标牵引模块的神经避撞决策系统.通过深入分析采样周期内威胁与机器人的相对速度、激光雷达有效探测距离以及威胁预测方位等因素对避撞机动效率和安全性的影响,对机器人各机动速度区的危险等级进行划分并建立相应的威胁度定量评估模型,再将其引入局部决策器以修正各节点的输出,进而提出了一种基于机动策略威胁度评估的神经动态避撞方法.仿真实验表明,相比于传统的神经导航,所提方法不仅优化了规避路径,而且代价更小.     

基于齐次变换的低空无人机防撞导引控制方法北大核心

针对传统低空无人机控制方法容易与障碍目标发生碰撞、安全飞行距离控制效果不好的问题,提出齐次变换的低空无人机防撞导引控制方法。建立三自由度模型,明确无人机飞行运动规律,计算视场内障碍目标方位,创建飞机、目标与视场的相对方位关联模型;利用齐次变换推算无人机与障碍点之间的距离,完成实时危险预警;对航行路线采取空间构建,改进无人机航迹路线,在路径搜索方式中代入启发式权重系数;运用加权值自适应方法获得航迹代价评估函数,对飞行纵向与横向依次设计导引控制律,完成准确的无人机障碍规避目标。仿真结果证实,所提方法防撞导引控制性能优秀,能够与障碍物保持安全飞行距离,可在现实场景中广泛使用。     

基于知识库的无人机作战自主决策方法的研究

提高无人机的自主决策能力是提升无人机在现代战争中作战能力的重要手段。通过对无人机对地作战过程的研究,分析归纳影响无人机自主决策的相关因素,并将无法用数学模型描述的军事规则使用产生式规则来表达,建立作战规则库。然后提出一种基于知识库的自主决策方法,该方法通过动态贝叶斯网络模拟人对态势的认知,通过产生式规则进行决策,其中加入实体的状态描述来控制决策流程,以此来完成无人机的自主决策。仿真结果表明,该方法科学有效,可使无人机自主做出合理决策。     

基于群集行为的分布式多无人机编队动态避障控制

针对无人机编队保持和动态障碍物规避控制问题,本文提出了一种新的基于群集行为的分布式多无人机编队控制和避障控制算法.首先考虑了由机间气流等因素带来的干扰,基于吸引/排斥势场和一致性方法,设计了分布式无人机编队的队形保持控制算法,对编队内无人机之间的距离进行控制.进一步考虑外部移动障碍对无人机编队的影响,引入了排斥势场产生...     

基于纳什议价的无人机编队自主重构控制方法

针对任务环境下携带不同载荷的无人机(Unmanned aerial vehicles, UAVs)组成的编队, 为实现无人机间的相互支援和补充而进行编队重构控制, 运用多目标多人博弈理论, 将其转化为纳什谈判过程. 结合分布式模型预测控制(Distributed model predictive control, DMPC)方法, 设计一种基于纳什谈判的分布式预测控制(Nash bargaining solution-DMPC, NBS-DMPC)算法求解该问题, 并对算法收敛性进行了证明. 仿真实验表明, 该算法能够有效控制编队自主重构, 实现编队无人机间的威胁规避和协同保护, 同时能够有效降低无人机编队自主重构控制问题的求解规模.     

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。