采用双向搜索在多权值路网中查找较优长路径

求解最短路径是图研究中的一个经典问题。目前大多数相关研究都假设图中每条边只有一种权值。然而在实际应用中,有时候图中的边设有多种权值,求解最短路时需要综合计算多种权值,并采用用户自定义的聚合函数f将路径的多种权值映射到一个实数上,用以比较路径的长短。当f不是线性函数时,最短路的子路不一定也是最短路,于是大部分求解最短路的算法对此问题并不适用。文中提出了一种双向搜索方法,用以在多权值路网中求解最短路近似解。实验表明,本方法适用于长路径查询。与单向搜索相比,该方法有较高的运行效率。与基于Dijkstra算法的贪心算法相比,该方法有较高的准确率。     

求解区间图K-连接最短路径问题的在线算法

针对含有n个区间的区间图K-连接最短路径(K-SP)问题,提出一种求解区间图K-SP问题的在线算法。分析区间图及其最短路径问题的特有性质,利用改进的动态规划算法和贪心算法,优化在线算法的时间复杂度。理论分析结果表明,该算法的时间复杂度为O(nK+nlgn),与目前已知最优的离线算法复杂度相同。     

动态网络最短路问题的复杂性与近似算法

有向网络的最短路问题在交通、通信系统的最优路径计算以及多阶段决策过程的最优轨线设计等实际问题中有着重要应用.经典模型及算法解决固定弧权条件下的最短路问题,而实际中,网络往往是动态的,即弧权依赖于时间变化,例如在交通拥堵时运行时间会变长,这时经典的最短路算法不再适用.文中证明了动态网络的最短路问题是NP-困难的;给出了最短路稳定性的充要条件,并在此基础上提出一种基于稳定区间的近似算法,通过模拟实验验证了该算法的有效性.     

散乱数据点集曲线重构的最短路逼近算法

给出了散乱数据点集曲线重构的最短路逼近算法．算法根据数据点的分布构造带权连通图,通过求解带权连通图的最短路径,将散乱数据点集的曲线重构问题转化为有序数据点集的曲线重构问题．算法可以对单连通、多连通和封闭的数据点集进行重构．重构曲线较好地保持了数据点集的形状和走向,尤其是带尖点的数据点集的形状特征．最后给出不同拓扑结构的数据点集的重构曲线实例．     

一种基于移动IPv6路由寻址的最短路径优化算法

移动IPv6的路由寻址是一个最短路径优化问题,最著名的两种最短路径算法是迪杰斯特拉(Dijkstra)算法和弗洛伊德(Floyd)算法,这两种算法的时间复杂度都是O(n3).本文通过对这两种经典算法的研究与分析,提出一种求最短路径的优化算法.该算法的时间复杂度是O(e*n),在连通图中,该算法能够比Floyd算法少近50%的迭代次数,在非连通图中e<相似文献   

带均匀分布权值的最短路问题

最短路问题是网络设计中的一个基本问题,当前研究工作都基于边的权值是确定的这一假设。论文研究边的权值是一区间数时的最短路问题,利用优化理论,建立了目标函数系数在区间上均匀分布的模糊线性整数规划模型。通过引入正、负理想点概念,将模型转化为具有确定系数的单目标优化问题,给出了求解算法,并证明了算法的时间复杂性是多项式时间的。仿真实例说明了模型和算法的有效性。     

基于字节指纹极值特征的数据分块算法

针对基于内容的数据分块算法中基本滑动窗口算法不能确定最大数据块的问题,提出一种基于字节指纹极值特征的数据分块算法。算法以上一个块边界点为起点构建最大块长区间,通过定义字节指纹极值域半径函数F并利用函数F值的分布特性,以概率1在允许的最大块长的区间内确定下一个块边界点。该算法克服了基本滑动窗口等分块算法不能确定最大分块长度的不足,其时间复杂度为O(n)。     

一类多约束最短路问题的模拟退火算法

讨论了一类NP-C问题——多弧权约束最短路问题．通过对搜索操作和参数的合理设置,提出求解多约束最短路问题的模拟退火算法,并通过对实例的计算表明该算法能快速,有效地求出多约束最短路问题的最优解。     

最短时限最少耗费指派问题的一种解法

对最短时限最少耗费指派问题分两步求解,第一步使用最大优先指派算法(MSFA)结合二分图匹配快速求解最短时限值;第二步在已求得的最短时限下,构造带权二分图,使用最小带权二分图指派算法求解,得到最短时限下的最少耗费指派解。所提出的求解方法思路简单清晰,便于计算机实现。     

基于区间的时间序列分类算法的研究

时间序列分类是时间序列数据挖掘的一个分支,针对传统时间序列分类模型存在的失真的问题,文章提出了基于区间权值的集成算法EAIW(Ensemble AlgorithmofInterval Weights)。首先利用区间权值计算方法,为时间序列的不同区间赋予不同的权值,对计算做了并行化处理,以解决子序列特征不明显的问题。进而确定集成分类器的基分类器,以保证集成分类器的性能。然后,在训练集上训练集成分类器,并行化改进集成分类器训练、分类较为耗时的部分。文章将提出的算法在时间序列分类数据库上进行了实验,结果表明提出的算法比基准算法最优正确率数目高25%,并且算法在并行化之后具备可伸缩性。     

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.