时间序列数据挖掘中特征表示与相似性度量研究综述

分别分析了时间序列特征表示和相似性度量在数据挖掘中的作用和意义,对目前已有的主要方法进行了综述,分析各自存在的优缺点;同时,探讨了将来值得关注的问题,为进一步研究时间序列数据的特征表示和相似性度量提供了方向。     

个性化搜索引擎推荐算法研究*

将个性化引入搜索引擎出现了稀疏性、精确性、扩展性等新问题。针对以上问题,提出了一种基于SVD（单值分解）影响集的协作过滤推荐算法,在利用矩阵相关技术以及扩大影响的基础上,将用户潜在感兴趣的资源推荐给用户。实验表明,该算法可有效解决以上存在的问题,显著提高个性化系统的推荐质量。     

基于语义向量模型的Web服务匹配方法*

针对当前Web服务匹配方法中存在的缺陷,将语义Web服务匹配方法与信息检索技术相结合,提出一种利用语义相似度扩展向量模型的Web服务匹配方法,并通过实验对匹配效果进行了检验与分析。实验结果证明,与基于经典向量模型的匹配方法和相关语义匹配方法相比,该匹配方法具有更高的准确率。     

平板边界层湍流的数值分析

对于不可压缩平板边界层的时间模式的直接数值模拟（DNS）而言,在转捩后继续计算,就可以得到湍流直接数值模拟结果．分析计算结果发现,当湍流充分发展后,其平均流剖面、各种量的脉动均方根值和雷诺应力等沿平板法向的分布都具有相似性．不过,从转捩完成至湍流充分发展之间有一过渡过程,其间上述相似性不成立．这一结果为简化但又较准确地计算工程技术问题中的湍流提供了一种可能性．此外,还分析了其他一些湍流特征,如形状因子和位移排移厚度随时间的演化规律．为了观察到相干结构,须将展向的计算域缩小一半,以增加分辨率,研究结果表明,湍流边界层近壁区存在相干结构,其主要表现是准流向涡或涡对．     

Web-Based Semantic Similarity: An Evaluation in the Biomedical Domain

Computation of semantic similarity between concepts is a very common problem in many language related tasks and knowledge domains. In the biomedical field, several approaches have been developed to deal with this issue by exploiting the structured knowledge available in domain ontologies (such as SNOMED-CT or MeSH) and specific, closed and reliable corpora (such as clinical data). However, in recent years, the enormous growth of the Web has motivated researchers to start using it as the corpus to assist semantic analysis of language. This paper proposes and evaluates the use of the Web as background corpus for measuring the similarity of biomedical concepts. Several ontology-based similarity measures have been studied and tested, using a benchmark composed by biomedical terms, comparing the results obtained when applying them to the Web against approaches in which specific clinical data were used. Results show that the similarity values obtained from the Web for ontology-based measures are at least and even more reliable than those obtained from specific clinical data, showing the suitability of the Web as information corpus for the biomedical domain.     

Composing Cardinal Direction Relations Based on Interval Algebra

Direction relations between extended spatial objects are important commonsense knowledge. Skiadopoulos proposed a formal model for representing direction relations between compound regions (the finite union of simple regions), known as SK-model. It perhaps is currently one of most cognitive plausible models for qualitative direction information, and has attracted interests from artificial intelligence and geographic information system. Originating from Allen first using composition table to process time interval constraints; composing has become the key technique in qualitative spatial reasoning to check the consistency. Due to the massive number of basic directions in SK-model, its composition becomes extraordinary complex. This paper proposed a novel algorithm for the composition. Basing the concepts of smallest rectangular directions and its original directions, it transforms the composition of basic cardinal direction relations into the composition of interval relations corresponding to Allen''s interval algebra. Comparing with existing methods, this algorithm has quite good dimensional extendibility, that is, it can be easily transferred to the tridimensional space with a few modifications.     

R&D项目价值评估的灰色B-S模型

针对传统净现值法不能有效评估RD项目价值的缺点,探讨了RD项目价值评估的适用方法,建立了基于区间灰数的RD项目价值评估灰色B-S模型,通过实例说明了该模型的有效性,并与传统净现值法的评估结果进行比较.结果表明,实物期权方法在评估RD项目价值时具有优势,为RD项目投资决策提供了一条新思路.     

基于模糊聚类分析中布尔矩阵法的一种改进算法

为避免布尔矩阵法中当截矩阵不是等价矩阵时需要对布尔矩阵重新构造才能实现分类,引入了分类对象间相似比的概念,引进了聚类分析中的布尔矩阵法.实例证明,与传统的几种分类方法的分类结果相比,改进算法得出的分类结果比较符合实际情况,更易让人接受和理解.     

增强Fisher判决的Bagging集成分类方法

提出了一种样本间的相似性度量方法,并将这种相似性度量信息附加到Fisher线性判别的类内、类间离散度矩阵,使得Fisher判决准则在使类内距离迭最小、类间距离迭最大的同时,也使类内相似度迭最小、类间相似度达最大,获得比原始Fisher判剐更好的投影矩阵。实验证明,与Bagging集成的Fisherfaee比较,该方法显示出更好的识别率。