面向存在不确定对象的组最近邻查询方法

组最近邻查询是空间对象查询领域的一类重要查询,通过该查询可找到距离给定查询点集最近的空间对象.由于图像分辨率或解析度的限制等因素,空间对象的存在不确定性广泛存在于某些涉及图像处理的查询应用中.这些对象位置数据的存在不确定性会对组最近邻查询结果产生影响.本文给出面向存在不确定对象的概率阈值组最近邻查询定义,设计了高效的查询处理机制,通过剪枝优化等手段提高概率阈值组最近邻查询效率,并进一步提出了高效概率阈值组最近邻查询算法.采用多个真实数据集对概率阈值组最近邻算法进行了实验验证,结果表明所提算法具有良好的查询效率.     

面向不确定数据的概率障碍k聚集最近邻查询

针对现有方法无法有效处理不确定数据的障碍k聚集最近邻查询问题的不足,提出了基于不确定Voronoi图的概率障碍k聚集最近邻查询(probabilistic obstacle k aggregate nearest neighbor query,POk ANN)方法。该方法分为3个阶段,分别是查询点集处理阶段、过滤阶段和精炼阶段。在处理阶段,计算查询点集的最小覆盖圆圆心q,为剪枝做准备。过滤阶段针对3种聚集函数设计了不同的过滤算法,去除不可能成为结果的数据点进而得到候选集合。精炼阶段将候选集合中概率值大于给定阈值的k个数据点集合存入结果集合并返回给用户。理论研究和实验表明,所提出的方法在概率障碍k聚集最近邻查询方面有明显的优势。     

一种面向不确定对象的可见k近邻查询算法

真实世界中,常存在很多障碍物,影响空间对象到查询点的可见性及距离,可见k近邻查询查找距查询点最近的k个可见对象,是时空查询领域的一类重要算法.由于度量设备误差以及通信开销的限制等因素,空间对象位置不确定因素广泛存在.文中拟对不确定对象执行可见k近邻查询,提出了概率可见k近邻(PVkNN)查询,即查找前k个成为查询点最近邻居概率最大的节点.为了高效地执行这一查询,文中提出了k-界限剪枝方法,基于可见质心的紧缩过滤以及对不可见对象的剪枝策略,从空间角度过滤掉不符合条件的对象.为避免对候选集合中每个对象的概率都进行精确计算,从概率角度提出了根据概率上下限来对候选集合进行进一步的求精方法,采用近似采样技术来获取可见区域的比例,实现了对PVkNN的高效计算.采用真实和模拟数据集设计实验,充分验证了算法的效率和精度.     

基于距离阈值的不确定图可达性查询处理

在不确定数据的处理中,不确定图作为典型的数据模型得到了广泛的关注,研究的内容包括基于不确定图的子图匹配、最近邻查询及连接查询等,本文研究基于距离阈值的不确定图可达性查询,即给定不确定图及图中任意两点s、t和距离阈值d,返回s和t的d可达的概率.提出一种基于随机抽样的可达性查询处理算法.定义了一种不确定图可能图实例的分类树模型.为了提高图实例分类的获取效率,提出基于双向遍历的优化分类树模型.设计了基于图实例类抽样的可达性查询处理算法并通过理论分析和实验验证了算法的性能.     

基于概率的反向K最近邻高效查询算法研究

反向K最近邻查询需要确定以给定查询对象作为其k个最近邻之一的所有对象。然而由于大量应用需要处理未知数据,人们迫切需要能够处理未知对象的新算法。这里的主要问题是,一个对象属于RKNN结果集的事件不再是一个确定性事件,而是一个以一定概率成立的随机变量。对基于概率论的未知数据集反向K最近邻(PRKNN)搜索问题展开研究,以足够大的概率返回以查询对象为其最近邻的未知对象。基于一种新的考虑了距离相关性的修剪机制,提出一种PRNN高效查询算法。此外,还给出了如何将该算法扩展至PRKNN(其中k>1)查询处理。最后,将该算法与当前其他最新算法作比较,实验评估结果表明,该算法性能明显优于其他算法。     

不确定数据上范围受限的最近邻查询算法

不确定数据的查询处理是数据库领域近年来的热点研究课题.提出一种不确定数据上的范围受限的最近邻查询.给定不确定数据集D={o1,o2,…,on},范围约束R是一个简单多边形,q为一固定的查询点,范围受限的最近邻查询返回的是在数据集D中,既满足范围约束R,又能成为查询点q的最近邻的对象集合.为处理该查询,提出了范围受限的最近邻核心集的概念和范围受限的最近邻核心集的查找算法.并提出一种计算范围受限的最近邻候选集的优化方法,降低了查询代价.最后通过实验验证了该算法的有效性.     

室内概率阈值反向最近邻查询

室内空间变得越发的庞大和复杂,随之产生了越来越多的室内空间查询需求.目前已有文献提出了针对室内空间环境的范围查询和最近邻查询,而作为常见的空间查询类型的反向最近邻查询,尚未有相关的研究.为此,提出了室内概率阈值反向最近邻查询和基于定位设备的设备可达图模型.在图模型基础上,提出了室内概率阈值反向最近邻查询处理算法,该算法由基于图模型的批量剪枝、基于室内距离的剪枝、基于概率的剪枝和概率计算4部分构成,通过剪枝策略修剪掉不可能出现在结果集中的对象,从而缩小了查询空间,提高了效率.     

受限网络移动对象的概率最近邻查询

基于自由空间移动对象概率最近邻查询,给出受限网络移动对象概率最近邻(CNPNN)查询概念,提出一种基于网络概率Voronoi图的CNPNN查询算法.利用基于网络距离的概率度量得到不确定数据的网络概率Voronoi单元,建立网络概率Voronoi 图覆盖受限网络.使用对点查询具有优势的R+树,对不确定数据的网络概率Voronoi单元进行索引,减少搜索时间.确定查询对象所在网络Voronoi单元,得到查询对象最可能的最近邻.实验结果表明,该算法时间复杂度为O(n2+mlogmn),在一定条件下具有较好的性能.     

一种局部相关不确定数据库快照集合上的概率频繁最近邻算法

局部相关空间不确定数据越来越受到许多实际应用的关注.提出了一种新颖的定义在不确定数据库的多个快照上的概率频繁近邻查询,目的是在多个快照数据上找到以一定概率频繁成为查询点最近邻的那些对象.应用现有的基于传统数据和基于不确定数据上的近邻查询算法直接处理这种查询会产生昂贵的开销.为了很好地解决这一问题,提出了一般的处理框架,...     

基于不确定数据的top-k概率相互最近邻查询*

不确定数据上的概率相互最近邻查询具有重要的实际应用,针对目前关于这方面的研究尚少,提出了不确定数据上的概率相互最近邻的top-k查询算法。首先对问题进行描述与定义,其次总结可行的裁剪规则,从而裁剪查询对象中未计算的实例点。通过实验表明,该算法能有效地降低最近邻查询中的I/O开销,提高查询的响应速度。     

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.