一种传输能量固定的数据聚集调度近似算法

针对现有的基于物理干扰模型的数据聚集调度近似算法具有较高的延时问题, 提出了一种改进的传输能量固定的数据聚集调度近似算法。该算法首先根据节点的通信半径构造一个网络通信图, 然后在该通信图中构造一棵数据聚集树, 使节点根据数据聚集树分层进行数据调度。在数据调度过程中, 首先将整个网络划分为若干个圆形区域, 然后对各个区域进行着色, 最后对颜色相同的区域同时进行节点的数据调度。理论分析表明, 该算法的延时上界为（X+1）²(Δ+12R+4)+R。仿真模拟结果表明, 该算法产生的数据聚集延时远低于现有算法。     

无线传感器网络中的改进数据聚集调度算法

针对现有聚集数据调度近似算法具有较高延时上界的问题,提出一种改进的聚集数据调度近似算法。建立一棵根在中心结点的广度优先搜索树,分层构造一个最大独立集(MIS),使MIS中相邻的2个结点相距两跳。将MIS中的结点连接起来,形成一棵根在中心结点的数据聚集调度树,使结点按数据聚集调度树进行分层数据调度。在数据聚集调度树的构造过程中,对于任意支配点,以最小的结点连接其相距两跳的支配点。对于2个相邻支配点的公共邻居支配点,通过在距中心点最近的支配点加入数据聚集树,使其在数据调度过程中将数据发送给距中心点最近的支配点,从而降低数据的聚集延时。实验结果表明,与SAS算法、Guo’s算法和IAS算法相比,该算法的数据聚集延时更低,其延时上界为14R+△?10。     

无线传感网中一种改进的分布式数据聚集调度算法

针对无线传感器网络中实时数据收集具有较高的延时问题, 提出了一种改进的无通信冲突的分布式数据聚集调度近似算法。该算法首先在最大独立集的基础上建立一棵根在sink的数据聚集树, 然后各个节点按数据聚集树分层进行数据调度。在数据聚集树的构造过程中, 对于两个相距两跳的支配点, 它们共同的、相距两跳的支配点, 通过距sink最近的支配点加入数据聚集树; 而在数据调度过程中, 采用一种新的选择标准从竞争集中选择节点进行数据调度。通过这两方面的改进, 有效地降低了数据的聚集延时。理论分析表明, 该算法的延时上界为14R+Δ; 仿真模拟的结果表明, 该算法产生的数据聚集延时远低于现有算法。     

受SINR约束的最小延时数据聚集调度算法

针对现有的基于物理干扰模型的数据聚集调度近似算法具有延时较高的问题,提出了一种改进的数据聚集调度近似算法。该算法首先构造一个连通支配集作为数据聚集树,使各节点根据数据聚集树分层进行数据调度;然后将整个网络划分为若干个边长相等的正方形区域,使每个区域中最多包含一个支配节点;最后对各个区域进行着色,并从颜色相同的每个正方形区域中任选一个普通节点,使它们能同时将数据汇聚到相应的支配节点。当数据从所有普通节点聚集到相应支配节点后,则将这些正方形区域构成一个大小相同的块,并采用四种颜色对这些块进行着色,使颜色相同的各个块中任选一条通信链路能够同时进行数据传输而不会发生通信冲突和干扰。理论分析表明,该算法的延时上界为K2Δ＋8K2R-3R;仿真模拟的结果表明,该算法产生的数据聚集延时低于现有算法。     

传感器网络中一种实时的自适应时隙调度算法

无线传感器网络节点数目众多,MAC协议为节点分配工作时隙面临能量利用不高、节点延时较长等方面的难题。目前基于时隙调度的MAC协议一般采用等长的时隙大小,不能适应数据流量变化大的网络且忽略与网络层的融合,没有利用路由层信息来减低时隙分配算法性能代价。提出一种基于路由转发树的时隙调度算法（ATSA）,网络采用簇结构,在簇内构造一棵路由转发树,根据路由转发树形成的路径信息对节点实时获取节点每轮需要发送的数据量大小,根据节点的数据量大小来分配节点每轮需要的时隙,然后由簇头据此动态地为成员节点分配时隙,降低时隙划分的能量和时间代价,减少空闲侦听时间,避免串音。仿真表明,该算法有效地提高了网络能量利用效率,延长了网络生存周期,降低数据包的延时。     

基于簇的无线传感网络流量负载的时隙调度协议*

针对大规模的无线传感器网络MAC协议在能量有效、低延时等方面的不足,提出一种基于簇的自适应时隙调度协议（ATSP）。整个网络由一些较小单位的簇组成,在每个簇内构造一棵数据聚集树,根据数据聚集树对节点每轮需要发送的数据流量进行加权,决定该节点的时隙大小;然后由簇头动态调节簇内节点时隙更新频率和顺序,可以降低时隙划分的能量和时间代价,减少节点的空闲侦听时间,避免串音。仿真表明,该协议有效地提高了网络能量有效性,延长了网络生存周期,降低数据包的延时。     

基于数据关联性的无线传感器网络簇内数据管理算法

无线传感器网络(Wireless sensor networks, WSNs)节点能量有限, 能量高效的数据管理和延长网络寿命是该领域的技术难题. 在以簇构建的传感器网络中, 利用节点的计算和分析功能, 提出了基于数据关联性的簇内数据管理算法. 簇头利用误差函数和模糊函数分析成员感知数据的关联性, 获取节点感知数据综合支持度, 由此将成员节点划分为冲突节点、补充节点和可靠节点, 对不同类别节点采用不同的调度规则以便降低簇内能耗和尽可能实现簇间节点能耗均衡, 并给出了簇头数据融合的处理方法. 仿真结果表明算法能够实现簇内数据分类管理, 并能有效降低簇内数据收发量和延长网络寿命.     

无线传感器网络中一种基于可靠性的数据收集算法

为实现无线传感器网络数据的低延时、高可靠性收集,将数据收集时涉及到的收集树构建、链路调度与功率分配联合问题定义为一个使数据收集延时最小化的优化问题。将该问题分成2个子问题：低延时数据收集树的构建和针对数据收集树的链路调度与功率分配,并为每个子问题提供一种多项式启发算法。仿真结果表明,与现有数据收集策略相比,该算法的数据收集延时明显降低,且可靠性更高。     

实现能量均衡消耗的簇内路由仿真研究

针对无线传感器网络中数据转发存在的高耗能以及传输延时等问题,提出一种新的路由算法。相对于传统的分层路由协议在簇内采用直接数据转发,即一个簇内的成员节点直接向簇头结点转发数据。该算法结合排队理论,在综合考虑影响簇中能量消耗和端到端延迟的因素的基础上指导节点采用直接数据转发或是间接数据转发方式进行数据发送。仿真实验表明,该算法具有良好的效率和实用性。     

无线传感器网络分簇拓扑的覆盖区域节点调度优化算法研究

利用区域分割的方法建立了一种覆盖区域冗余节点的优化调度机制,实现对完全覆盖区域内冗余节点的休眠调度,并将该机制引入无线传感器网络的分簇结构中,提出一种基于分簇拓扑的节点调度优化算法。算法通过控制簇内冗余节点进行休眠,减少簇首的数据通信量和簇成员中工作的冗余节点个数,降低了网络能耗。仿真结果表明,与未考虑冗余节点休眠调度的分簇算法相比,该算法有效提高了网络能量利用率,延长了网络生命期。     

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.