蚁群算法在无线传感器网络中的应用研究

针对蚁群算法（Ant ColoW System,ACS）在无线传感器网络路由中对网络拥塞问题和能量控制方面的不足,提出了一种改进的蚁群算法。该算法将蚁群的信息素与网络节点的能量结合起来,在蚁群算法收敛的同时,通过动态地调整信息素来减少其最优路径上的信息素浓度．通过采用最优、最差路径信息素全局更新策略加快搜索速度,避免了网络拥塞和个别节点能量消耗过快的问题。从而延长了整个网络的生命周期。通过实验验证了该方法的可行性,并给出了实验结果。     

EE-UDRA: 带环境元素的水下传感器网络分布式路由算法

现阶段的水下传感器网络(UWSN,underwater sensor networks)路由算法的研究工作大多都没有对部署的水下环境做具体分析,不同水下环境与网络性能之间的相关性研究较少,同时针对水下信道利用率低、能量消耗和延迟时间较大等问题,提出融合了环境元素的水下传感器网络分布式路由算法(EE-UDRA),分析了不同的水下传播环境以及环境元素对路由算法性能的影响,通过增长型分组队列的管理方法重点解决了水下信道利用率较低的问题,并在提高信道利用率的基础上通过分析能耗或延迟的可控因素来寻找能耗最低或延迟最小的路由路径。实验结果显示,环境元素对相同算法的运行结果带来了一定的影响。在提高信道利用率的同时,EE-UDRA算法选择的最佳路由路径在减少能量消耗,缩短延迟时间上具有较好的效果。     

改进的蚁群算法网络节点覆盖优化研究

研究无线网络节点覆盖优化问题,由于传感器网络节点冗余和供电能量限制,影响网络的生命周期.针对当前传感器网络存在的热区问题,导致求解困难,提出一种将蚁群算法运用到无线传感器网络节点最优覆盖问题上.充分利用了蚁群优化算法的优点,算法首先对网络中的节点进行非均匀部署,将信息素放置在传感器网络节点上,每个节点赋予两个信息素,分别指示该节点两个不同的信息量.在算法中设置了有效的启发式信息以引导蚂蚁的搜索行为.蚂蚁将根据信息素和启发式信息决定使用哪些节点进行覆盖,进行建立求解模型,将模型变为简单的线性规划问题.仿真结果表明,当前经典的网络节点覆盖算法相比,算法提高网络覆盖率、降低了网络能耗,并对优化网络节点覆盖.     

基于改进蚁群优化的无线传感器网络路由算法

针对无线传感器网络节点能量、通信能力有限等特点,提出了一种改进蚁群优化的路由算法,算法对下一节点的选择充分考虑了通信距离和剩余能量等因素,将蚂蚁搜索行为集中到最优解附近,为避免早熟收敛行为的发生,将信息素轨迹的值域范围进行限制,通过对信息素轨迹的平滑化,快速逼近无线传感器网络最优路径;仿真结果证明,该算法有效地减少了网络能量消耗、节点死亡数量和链路长度,延长了网络生命期。     

蚁群优化算法在WSN路由中的应用研究

介绍了基本蚁群算法的原理和适用范围,总结出了基本蚁群算法在求解最优路径问题时,虽然具有很强的发现较优解的能力,但是存在容易陷入局部最优解和收敛时间过长等问题。考虑到基本蚁群算法在无线传感器网络路由上应用的不足,提出了一种改进后的蚁群算法,并将其应用到传感器网络路由中。该算法不仅在状态转移概率公式中引入罚函数和动态权重因子,而且采用局部信息素更新和全局信息素更新结合的方式更新路径信息,充分考虑到传感器节点与节点间的传输距离,并且充分考虑传感器节点的剩余能量。最后通过仿真实验,得到了基本蚁群算法和改进后的蚁群算法在传感器节点剩余能量和传输数据包时网络延迟的不同曲线,验证了改进后的蚁群算法在无线传感器网络路由选择上的高效性。     

蚁群优化的无线传感器网络路由仿真研究

针对无线传感器节点提供能鼍的电池有限,因此无线传感器网络的路由设计应有效地利用能量.为了有效地延长网络的生命周期,提出了一种基于蚁群优化的尤线传感器网络路由算法.首先根据节点剩余的能量进行簇头选择;然后通过简单易于实现、支持多路径的蚁群算法进行路由选择,通过相邻簇头节点间广播各自的距离和剩余能景信息,在整个网络中建立与更新簇头间的蚁群信息素浓度;最后根据蚁群信息素浓度计算各相邻簇头被选择作为下一跳的概率,从而形成网络簇间路由.在NS2平台下进行了仿真实验,实验结果表明,与LEAcH算法相比,减少了平均能耗,网络存活节点数增加,有效地延长了网络生命期.结果证明,蚁群算法在无线传感器网络中能够很好的找到最佳路由.     

融合粒子群与改进蚁群算法的AUV路径规划算法

针对传统蚁群算法在处理自主式水下机器人AUV（Autonomous Underwater Vehicle）三维路径规划问题时存在初期寻径能力弱、算法收敛速度慢等问题,提出一种融合粒子群与改进蚁群算法的AUV路径规划算法PSO-ACO（Particle Swarm Optimization-improved Ant Colony Optimization）。基于空间分层思想建立三维栅格模型实现水下环境建模;综合考虑路径长度、崎岖性、危险性等因素建立路径评价模型;先使用粒子群算法预搜索路径来优化蚁群算法的初始信息素;再对蚁群算法改进状态转移规则、信息素更新方式并加入奖惩机制实现全局路径规划。实验表明,算法能有效提高初期寻径能力和全局搜索能力,减少收敛迭代次数并缩短搜索使用时间。     

无线传感器网络中基于蚁群算法的能量空洞规避策略

无线传感器网络(WSN)具有特殊的能量空洞(Energy Hole)现象,蚁群算法的随机自适应性使其很适合应用于无线传感器网络环境,所以在缓解能量空洞有效性分析的基础上,提出了一种基于蚁群算法的局部区域能量空洞规避策略,通过蚁群算法的自适应性实现了无线传感器网络运行过程中能量空洞规避,搜索出一条最优路径。仿真实验表明,该算法能够有效地延长网络的生命周期。     

一种基于蚁群算法的WSN路由算法

针对蚁群算法（Ant Colony System,ACS）在无线传感器网络路由中对网络拥塞问题和能量控制方面的不足,提出了一种改进的蚁群算法。该算法将蚁群的信息素与网络节点的能量结合起来,在蚁群算法收敛的同时,减少其最优路径上的信息素浓度,避免了网络拥塞和个别节点能量消耗过快的问题,从而延长了整个网络的生命周期。通过实验验证了该方法的可行性,并给出了实验结果。     

一种均衡能量的自适应蚁群路由算法

由于网络结构多变和节点资源受限等问题,新型自组织网络都要求其路由协议不仅具有自适应性,而且要能够感知能量.提出一种能够均衡能量的自适应蚁群路由算法.该算法将作为节点参数的能量转化为链路参数,然后使用含有节点能量利用率的网络延迟作为路由代价度量,从而使得信息素既能够表示路径质量,又能够表示路径上的节点能量利用率,因此数据包逐跳路由时能够合理选择出下一跳节点.同时,蚁群优化使得该算法能够自适应网络变化,平衡流量.基于NS2的模拟实验证明该算法能够均衡节点能量从而具有较好的性能.     

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.