异构群体队形光滑变换控制方法

针对现有群体队形控制方法在队形变换异构性、光滑性、条理性等方面的不足,提出一种基于几何约束机制的受限异构群体队形控制方法.首先采用Morphing方法生成由初始形状平滑变换到目标形状的一系列中间约束形状;然后引入基于质心的容量限制Power图对个体在约束形状中的内部布局进行建模,产生所需的异构分布;最后提出面向Power图的Lloyd导航算法,以控制个体进行无碰撞的光滑移动.实验结果表明,该方法稳定可靠,队形变换平滑流畅,非均匀人群分布可用于制作自然的群组动画和仿真真实场景,适用于不同规模、不同队形的异构群体队形控制.     

基于Voronoi图的群体队形控制方法

影视作品中采用群体队形控制技术来制作大量角色处于某种队形运动的场景，但许多群体队形技术往往侧重于对自由移动的个体角色进行控制，而忽视了对队形运动的整体控制，导致场景画面缺乏美感性、整体性和条理性。针对这些问题，提出了基于Voronoi图的群体队形控制方法。首先，将群体队形进行Voronoi图空间划分，建立一个包含所有智能体的队形网格；然后，提出一种新的群体队形形变算法，采用人工势能场和相对速度障碍法进行合理避障，再结合弹簧系统使群体队形在形变过程中尽可能保持整体稳定；最后，采用Lloyd算法快速恢复到目标队形。实验结果表明，该方法可以很好地模拟群体队形变换运动，适用各种复杂场景，具有美感、整体、条理的队形变换效果。     

群组动画中的队形约束与控制方法

针对影视制作中对大规模虚拟群体运动控制的需求,提出一种基于队形约束的群体运动编辑与控制方法.首先利用贪心算法构建从初始队形到目标队形中个体位置的配对关系;然后对其进行优化,在保持个体相对位置的同时尽可能减少路线交叉;最后通过匹配虚拟角色的运动来合成流畅、逼真的群组动画.采用文中方法用户只需输入群体规模以及群体队形轮廓,即可实现对群体运动的编辑与控制.实验结果表明,该方法能够对不同规模、不同队形间的群体运动实现有效控制,从而提高群组动画制作的效率.     

群体动画中路径自动规划方法研究

为了在制作群体动画时产生逼真的运动路径,在群体运动的模拟中设计了碰撞检测和碰撞避免的方法,并基于微粒群算法和人工蜂群算法提出了群体动画路径自动规划方法.仿真实验表明;该方法能够实现群体动画运动路径的自动设计,提高了群体动画的制作效率.     

团体操虚拟编排和演练原型系统

采用有指导的虚拟人群仿真技术，对团体操编排和演练进行计算机仿真，设计并实现了一个团体操编排和演练原型系统，该系统由团体操队形及图案设计子系统和团体操虚拟排练子系统构成．给出了系统结构与功能，并介绍了系统实现的路径规划、避碰和实时绘制等关键技术．实验结果表明，该系统能够为团体操创编人员改进队形与图案变化的设计质量和提高设计效率提供方便，为团体操编排和演练人员提供辅助工具．     

一种保持Agent团队队形的路径规划方法

Agent团队能够在动态环境中完成复杂的任务,路径规划同题是Agent团队研究的主要问题之一.对Agent团队的路径规划问题进行了分析,提出了一种保持Agent团队队形的规划算法(ATPP).该算法是一种集中式的全局规划方法,使用改进的A*算法得到Leader的路径,通过对Leader路径的优化得到关键点表和队形转换表,利用关键点表和队形转换表得到团队中非Leader成员的路径.队形转换表可以使行进中的队形变换更合理,并且减少了队形维护时需要的通信量.通过调整算法中的两个影响因子,可以分别得到侧重于队形和侧重于距离的路径,改进了Hao的方法.     

改进遗传算法与领航跟随法的机器人编队方法

针对传统遗传算法在求解机器人路径规划问题时存在的收敛速度慢、路径不平滑问题,对其进行了改进,在适应度函数中加入了路径平滑度因素,选择操作时平滑度较好的路径更容易被选中。在种群选择时将最优个体直接复制到下一代,有效地保留了父代优良基因。在领航机器人规划路径阶段,使用改进的遗传算法为领航机器人规划出一条安全无碰撞且平滑度较好的最优路径。在跟随机器人跟随阶段,使用领航跟随法控制每一个跟随机器人使其与领航者保持特定的距离与角度,从而形成设定的队形。最后通过MATLAB软件建立栅格地图进行仿真,验证了该算法的可行性,与传统遗传算法相比,改进遗传算法收敛速度更快,且路径更加平滑。     

Agent-Based群体模拟中的朝向计算方法

基于智能体(agent-based)的群体模拟中,已有的朝向计算方法易产生个体的朝向突变或僵硬的转弯行为,导致高密度群体的三维运动效果失真.为此提出一种适用于agent-based模型的双层朝向处理方法.在理论层上,依据角动量约束构建出朝向旋转方程,在计算路径过程中综合考虑个体期望方向、角速度约束、外部干扰转动等因素,计算个体朝向的初值;在数据层上,采用朝向过滤技术对初值进行处理,并在四元素空间内进行球面插值,最终生成群体的运动朝向.实验结果证明,该方法能实时地计算出自然平滑的高密度群体朝向数据.     

多机器人协同队形变换算法与实现

在面向任务的应用中,越来越多的任务需要多机器人协作才能完成.多机器人编队能有效提高任务完成效率并且保证可靠性,与单个机器人相比具有相当的优势.多个机器人要保持一个稳定的队形,其系统内部必须有信息的传递和交换.多机器人之间的队形保持难点在于每个机器人之间要实时获取其它机器人的位置坐标信息并且根据拓扑约束进行反馈调节.为解决上述问题,提出采用分布式控制和局部通信机制,避免使用全局绝对坐标.根据多机器人的物理约束、信息交换和控制策略建立并实现了多机器人编队的l-(φ)-l模型,与传统算法相比,实现了领航者根据跟随者的信息进行自身调节,提高了队形保持的稳定性.从仿真结果看,多个机器人能快速地进行队形变换,变换过程中没有相互的碰撞,并可以顺利通过障碍物,队形误差小.     

可变形网格引导的群体队形仿真

目的 许多群体运动仿真算法侧重于模拟由大量自由移动个体所组成的群体行为,而针对具有特定队形的群体运动仿真算法较少。为解决这一问题,采用改进的网格引导方法,利用可变形网格对群体运动进行控制。方法 首先,对群体队形进行三角划分,建立一个连接所有智能体的队形网格。然后,利用障碍势场法在群体运动的过程中对队形网格进行变形,使智能体在避免与障碍物发生穿透的同时尽可能保持整体队形稳定。最后,针对障碍物穿过队形网格时可能造成的局部智能体 “错位现象”,提出了基于吸引点的网格引导方法,使群体绕过障碍物后能迅速恢复原来队形。结果 使用Unity软件对军队行进、动态车流、群体表演等场景中的智能体编队移动进行仿真,并设置了不同规模的群组交换实验进行对比。本文算法的实时计算花销主要集中在网格变形阶段：在队形网格顶点总数为1 000时,单位仿真步内网格变形阶段的平均运行时间为20.15 ms。队形网格划分阶段是一个预先进行的过程,不影响算法实时性。基于吸引点的网格引导方法提高了智能体的全局移动效率,使队形变化更加自然流畅。结论 实验结果表明,可变形网格引导的群体队形仿真算法在群体运动过程中能有效维持队形稳定,无论障碍环境是静态的还是动态的都能实现良好的群体避障,说明算法的有效性。     

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。     

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.