一种基于局部随机游走的标签传播算法

社区结构是复杂网络的重要特征之一,识别网络中不同功能的社区对理解复杂网络特性具有重要作用。基于标签传播的社区发现算法通常以节点的直接邻居作为邻域更新标签,可能无法准确发现社区结构或导致得到的社区划分结果不稳定。针对此问题,提出了一种基于局部随机游走的标签传播算法(Local Random Walk Based Label Propagation Algorithm, LRW-LPA),利用节点的k步邻域内局部重要性指标选择重要性最低的节点作为起始节点,进行带重启的局部随机游走以确定起始节点的局部邻域;选择此局部邻域范围内出现次数最多且影响值最大的标签来更新起始节点标签。LRW-LPA采用带重启的局部随机游走过程能更准确地确定节点的合适邻域范围,提高了算法的稳定性。与LPA,BGLL,Infomap, Leiden, Walktrap等经典社区发现算法在12个真实网络和12个人工构造网络上的比较实验表明,LRW-LPA算法在标准互信息(NMI)、调整兰德系数(ARI)和模块度(Q)等方面表现良好。     

一种新的基于标签传播的复杂网络重叠社区识别算法

针对现有基于标签传播的复杂网络重叠社区识别方法所存在的社区识别精度不稳定,以及随机性较强等缺陷,提出一种新的基于标签传播的复杂网络重叠社区识别算法NOCDLP(a novel algorithm for overlapping community detection based on label propagation).该算法首先搜索网络中若干以度较高节点为中心的完全子图,并以这些完全子图为起点进行标签传播;其次通过分析节点与社区连接强度以及社区接纳某节点后的社区内部连接紧密度情况给出节点归属社区强度函数,以此作为标签传播的依据提高社区的识别精度;再次,在标签传播过程中,NOCDLP算法设置标签传播控制标记,以避免标签传播算法随机性较强的缺陷;最后,在已形成的社区中通过整理重叠节点获得更准确的重叠社区结构.算法在人工网络与真实网络中完成测试,同时与多个经典算法进行对比分析,实验结果验证了NOCDLP算法是有效的、可行的.     

融合特征向量中心性与标签熵的标签传播算法

重叠社区结构挖掘旨在发现复杂网络中多个独立社区之间的重叠部分，其在社交、交通、舆情乃至反恐等领域具有广泛的应用。然而，目前基于标签传播的重叠社区挖掘算法在社区结构模糊的网络中表现出较强的随机性，导致准确度不高。针对重叠社区模糊边界导致的不确定性和低准确度问题，提出一种融合特征向量中心性与标签熵的标签传播算法ECLE-LPA。ECLE-LPA通过融合节点的K-核迭代因子与特征向量中心性来计算节点影响力并初始化节点标签，在标签传播过程中，通过节点标签熵和节点间亲密度更新节点标签列表及其标签隶属度，从而较好地克服了社区模糊边界的识别问题。实验结果表明：在Les Miserables、Polbooks、Football、Polblogs和Netscience等真实网络中，ECLE-LPA划分结果的EQ值普遍比对比算法提高了1%～3%;在社区结构模糊的人工网络中，ECLE-LPA划分结果的NMI值比其他标签传播算法提高了10%以上。     

基于深度强化学习的复杂网络可扩展社区检测

针对复杂网络社区检测可扩展性不足与准确性不高的问题,提出一种复杂网络可扩展社区检测算法。该算法由两个阶段构成,第一阶段根据邻域度数方差检测网络中的候选社区中心,基于网络拓扑结构评估节点的相似性,基于相似性进行标签传播,建立网络的初始化社区;第二阶段基于深度强化学习对网络社区结构进行微调与优化,利用深度强化学习强大的感知能力与决策能力提高社区结构的准确性。实验结果表明,由该算法发现的网络社区获得了较高的准确性。     

基于标签传播的两阶段社区检测算法

社区检测是复杂网络分析的重要研究任务之一,其检测结果有助于人们深入理解复杂网络的社区结构,同时为下游任务提供支持,如内容推荐、链路检测等。针对复杂网络的社区检测问题,提出了一种基于标签传播的两阶段社区检测算法——TS-LPA。TS-LPA采用扩展邻域的思想来量化节点的传播能力,并在此基础上,利用节点信息和网络中边的权重等信息,提出了新的评价指标来衡量节点的中心性和节点之间的影响力。所提算法在计算节点中心性的基础上确定了节点标签更新的顺序和种子节点的选择策略,消除了算法在更新过程中的不稳定。在节点标签更新的过程中,为了更好地利用邻居节点标签类别来进行标签更新,TS-LPA采用广度优先传播的思想,提出了第二阶段标签传播方式。当标签开始传播的时候,待更新节点的所有邻居节点都对该节点的类别标签产生影响,同时,为了减轻周围邻居节点对待更新节点的支配程度,除邻居节点的影响外,加入附近种子节点对待更新节点的影响,共同完成节点的标签更新。在不同的真实数据集和人工合成数据集的实验结果分析表明,TS-LPA在消除随机性、表现出较强稳定性的同时,有效提高了社区检测的质量。     

一种优化的标签传播方法

社区发现是复杂网络分析领域的一项重要研究内容,而标签传播算法因在分析复杂网络时具有时间复杂度低等优点,获得广泛关注.但标签传播算法中的随机策略降低社区划分结果的稳定性和效率.为解决随机策略引起的问题,提出了一种优化的标签传播方法.该方法引入标签权重,并与标签一起组成二元组,根据标签二元组、节点间的联系度等因素为节点分配初始化标签;同时,在标签传播过程中,根据节点间的联系度等因素进行标签更新.实验结果证明了该方法的有效性和有用性.     

基于随机游走的改进标签传播算法

社区发现是挖掘社交网络隐藏信息的一个有用的工具,而标签传播算法（LPA）是社区发现算法中的一种常见算法,不需要任何的先验知识,且运行速度快。针对标签传播算法有很强的随机性而导致的社区发现算法结果不稳定的问题,提出了一种基于随机游走的改进标签传播算法（LPARW）。首先,根据在网络上进行随机游走确定了节点重要性的排序,从而得到节点的更新顺序;然后,遍历节点的更新序列,对每个节点将其与排序在其之前的节点进行相似性计算,若该节点与排序在其之前的节点是邻居节点且它们之间的相似性大于阈值,则将排序在其之前的节点选为种子节点;最后,将种子节点的标签传播给其余的节点,得到社区的最终划分结果。将所提算法与一些经典的标签传播算法在4个有标签的网络和5个无标签的真实网络上进行比较分析,实验结果表明所提算法在标准互信息（NMI）、调整兰德系数（ARI）和模块度等经典的评价指标上的性能均优于其余对比算法,可见该算法具有很好的社区划分效果。     

基于三级邻居影响力分析的重叠社区发现算法

针对目前重叠社区发现算法时间复杂度较高、社区发现稳定性较差的问题,基于标签传播和COPRA方法,提出一种基于三级邻居节点影响力分析的重叠社区发现算法OCDITN。使用三级邻居节点影响力度量方法TIM(three-level influence measurement)计算节点间的影响力,根据节点影响力确定选择更新节点的顺序;在节点标签更新策略中,根据计算节点与其邻居之间的相似度确定邻居节点标签的更新顺序,计算各节点标签隶属度,发现重叠社区。实验分别基于人工模拟网络数据集和真实世界网络数据集进行测试,与SLPA、LPANNI、COPRA算法相比,该算法在EQ和Qvo两个评价标准上性能分别提升7%和12%,社区划分结果更稳定,社区划分质量更高。     

基于多标签传播的重叠社区发现优化算法

标签传播算法是一种被广泛应用的社区发现算法,该算法为网络中的每个节点分配一个初始标签,然后通过传播标签来发现复杂网络中的潜在社区,具有时间复杂度低的特点。当前基于标签传播的重叠社区发现算法存在忽略节点重要性差异、需要人为设置参数等不足。针对该类算法在重叠社区发现方面的缺陷,提出一种基于多标签传播的重叠社区发现优化算法。该算法使用K-核分解方法找出若干个社区核心节点,以这些节点为种子节点,逐层向外传播标签;在进行标签选择的时候以邻居节点标签的种类来决定重叠节点的标签个数。实验表明,该算法明显改善了社区发现的性能,提高了划分结果的稳定性和准确性。     

基于社区划分的节点重要性评估方法

对于PageRank方法结果过于集中,未考虑复杂网络社区结构特性的问题,提出了一种改进的,基于复杂网络社区划分的节点重要性排序方法CD-PR。根据标签传播算法（LPA）对复杂网络进行社区划分的结果,将社区的内外连接关系转化为社区选择的概率表示;按照社区选择概率,分别从各个社区提取一定比例的候选关键节点;将这些候选节点重新排序,得到关键节点排序结果。以4个真实复杂网络作为实验数据,与现有算法进行对比,进行SIR传播性能实验。实验结果表明,CD-PR算法筛选出的节点在整体传播性能上具有更好的效果,CD-PR算法可以有效地对复杂网络的节点进行重要性排序。     

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.