基于AUVs的水下移动无线传感器网络愈合算法

水下移动无线传感器网络（MUWSNs）动态演化特性制约着网络的拓扑的可靠性,很大程度上限制了MUWSNs的推广应用。针对水下实体移动导致的MUWSNs拓扑失效,提出了一种基于自主式水下航行器（AUV）的MUWSNs拓扑愈合算法,并构建了水下实体移动模型,利用AUV自主移动特性对失效拓扑进行快速愈合。仿真结果验证了该算法的正确性和有效性,极大地提高了MUWSNs可靠性,对MUWSNs拓扑领域研究具有一定贡献。     

水下移动无线传感器网络拓扑

水下移动无线传感器网络是当今世界各国的研究热点之一. 水下复杂环境以及传感器节点移动特性使得水 下移动无线传感器网络拓扑具备了动态演化性, 同时, 水声通信也对水下移动无线传感器网络的可靠性产生了一定 影响. 首先归纳分析水下移动无线传感器网络国内外的研究现状及进展, 并剖析了水声通信对水下移动无线传感器 网络拓扑的影响; 然后凝炼出3 个科学问题, 重点论述了拓扑生成、拓扑愈合及拓扑优化; 最后对未来研究方向进行 了展望, 以期为该领域的深入研究提供清晰的思路.

     

基于移动Agent的无线传感器网络拓扑发现机制

对监测区域中部署的传感器节点的拓扑发现是传感器网络应用的前提,它反映了传感器网络的监测能力。考虑目前拓扑发现算法中能量消耗过多、网络连通性不强等问题,文中结合移动Agent的特点,提出了一种基于移动Agent的无线传感器网络拓扑发现机制,通过建立数学模型,利用相关邻近图（relative neighborhood graph）理论生成网络拓扑。实验结果表明,基于移动Agent的拓扑发现机制相对于当前存在的拓扑发现算法具有很好的稳定性和良好的节能效果,该算法可以解决节点拓扑请求信息讨多导致过多能量消耗的问颢．     

基于移动WSN目标追踪算法

水下移动无线传感器网络是追踪水下目标的重要手段,由于水下环境复杂,传感器节点会因为损坏或能量耗尽等问题脱离WSN网络,造成目标追踪困难。针对该问题,在拓扑熵理论基础上建立移动WSN目标追踪算法模型,利用拓扑熵对空间中点集拓扑关系描述移动WSN节点的部署情况。当有节点脱网后,通过不断计算拓扑熵值的变化合理调度节点移动,实现节点移动过程中的分布式自适应部署。仿真结果表明,在传感器节点损耗的情况下,提出算法和现有WSN目标追踪方法相比,在优化移动传感器网络的部署和目标追踪方面,具有更高的算法性能和效率。     

水下无线传感器网络节点部署优化研究

为降低水下传感器网络的部署成本,文中对水下无线传感器节点数目和覆盖率进行优化,提出了针对不同网络拓扑模型的水下无线传感器节点部署优化模型。首先,分析不同网络模型对覆盖性能的影响;然后,利用遗传算法求解优化问题,分别以网络节点数目和覆盖率作为适应度函数求解。通过仿真实验验证了该算法的有效性,结果显示:该策略能够在单个传感器覆盖半径减少的情况下以更少的节点数目达到更高的覆盖率,从而降低水下传感器网络节点部署成本。     

无线传感器网络的拓扑控制研究*

讨论了拓扑控制的目标,利用随机图理论研究了无线传感器网络拓扑控制的模型及代表性算法;基于网络结构的不同,分析和比较了无线传感器网络中各种拓扑控制机制的特征;深层剖析了无线传感器网络拓扑控制与连通、调度之间的关系;最后对拓扑控制亟待解决的问题进行了总结和展望。     

基于小世界模型的WSN簇间拓扑优化方法

针对无线传感器网络节点因能量消耗、硬件故障、通信因素等导致的链路失效问题,提出一种基于复杂网络小世界模型Kleinberg的无线传感器网络簇间拓扑优化方法,该方法依据簇头节点的局部视图ViewList信息中的长链与短链构建WSN簇间拓扑.实验分析表明,利用该方法演化的无线传感器网络拓扑在节点失效概率为0.2时,网络寿命比DECDC提高25%,并具有良好的能量均衡性和较低的消耗代价.该方法构建的拓扑具有较好的容错性和较强的鲁棒性.     

基于无线传感器的物联网网络拓扑发现算法研究

在基于无线传感器的物联网中,由于传感器硬件设备的局限性和动态性,以及组成的网络通信带宽有限等,在网络中准确、及时地获取网络的拓扑信息变得非常困难,而如何全面、准确、快速地进行网络拓扑发现对于物联网的网络管理、故障定位和拥塞控制等研究和更多的上层应用具有重要的意义。提出了一种基于移动代理的模糊动态拓扑发现算法的设计方案。不仅通过构造网络模糊拓扑信息的处理方法和移动代理的迁移、活跃度等相关策略模型,给出了移动代理和传感器节点的最优拓扑发现数量比,而且还根据模糊知识处理已有的研究,获得了完整的基于传感器的物联网网络拓扑发现算法。通过实验验证表明,本算法不仅改进了网络拓扑的发现效率,并且具有较小的网络能耗等。     

无线传感器网络非均匀等级分簇拓扑结构研究

网络拓扑结构影响着传感器节点的负载均衡与生存周期,分簇结构是无线传感网络的一种有效地拓扑管理方式。根据血管网络特征以及对构建无线传感器网络拓扑结构的启示,提出了无线传感器网络非均匀等级分簇拓扑结构。分析血管网络结构特征,建立数学模型和网络拓扑结构,对具有压力差的网络节点进行等级标定。根据改进粒子群算法进行非等概率静态分簇,形成不同等级区域具有密度和规模不等的非均匀等级分簇拓扑结构。仿真分析表明,此算法能优化网络分簇,均衡节点能耗,延长网络生命期,避免网络能耗热点问题。     

基于半监督拉普拉斯映射的移动定位算法

在无线传感器网络节点移动定位过程中,网络拓扑结构不断进行更新,以致影响预测模型的精确度。为此,提出一种基于拉普拉斯映射的移动定位算法。分析无线传感器网络的布局特点,引入局部拓扑结构和非信标节点信息,将节点定位问题放在半监督框架中进行研究。实验结果表明,与同类算法相比,该算法提高了预测模型的泛化能力和节点的定位精度,具有更高的稳定性。     

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.