基于改进K-means聚类的案例检索策略

针对目前基于案例推理系统中案例检索存在的问题,根据K-means算法思想,分别设计一个案例聚类算法及案例检索算法。根据K-means算法的不足,对初值选取规则及案例检索算法进行改进。分析基于案例权重的样本案例选取规则,并论述案例聚类算法和检索算法。实验结果表明,该方法能有效提高案例检索效率及案例检索结果的召回率。     

基于蚁群的图像情感特征聚类算法的研究

随着图像检索系统的发展,合理地组织和管理图像数据库已经逐渐成为图像检索的关键。首次将蚁群聚类算法应用在基于图像特征的情感聚类分析中,并对原有的蚁群聚类算法进行了改进。该算法通过计算样本间的欧式距离确定起始蚂蚁,模拟蚂蚁对食物的捡起和丢弃行为,根据提取的图像主颜色特征,对图像情感进行聚类。实验表明该算法能够取得较好的聚类效果和较高的检索效率。     

聚类技术在图像检索中的应用

本文从聚类技术对提高图像检索效率方面的改善,介绍了聚类技术的基本理论和在图像检索系统应用.     

基于CBR的信息系统案例检索多Agent模型研究

将Multi-Agent技术应用于信息系统案例检索中,结合CBR技术与Web Service思想,提出了基于CBR的信息系统案例检索多Agent系统的模型框架和运作流程,设计了基于智能聚类的案例检索算法,通过神经网络的自组织学习优化案例检索的过程,使得该多Agent系统成为具有高度自治性的自我学习与完善的系统,为信息系统案例检索系统的研究与开发提供了一定的借鉴.     

基于网格聚类的案例检索策略

基于案例推理的智能推荐系统是大型科学仪器协作共用网的重要组成部分。通过对案例库按网格进行聚类,设计并实现一个基于异构案例库的检索策略。分析案例库网格划分原则及案例聚类规则,论述案例聚类算法及在聚类基础上的案例检索策略。实验结果表明,该方法能够有效地降低案例检索时间,提高案例库的可维护性。     

一种k-means聚类的案例检索算法

针对CBR系统中案例检索算法存在的问题,根据k-means算法思想,将案例库进行聚类,在聚类基础上设计了一个案例检索算法。分析了样本案例的选取规则,重点论述了案例检索算法。根据实验结果表明,该方法能够有效地提高案例检索结果的召回率及案例检索效率。     

基于交互式遗传算法和粗糙集的图像检索方法

针对如何在图像检索系统中客观地表达用户的感知,提出了一种基于粗糙集和遗传算法的相关反馈图像检索方法.采用粗糙集的方法求出图像的最简视觉特征子集,采用交互式遗传算法,对每一次反馈得到的候选图像集进行评价,利用遗传算子从图像库中选出接近用户需求的图像.实验表明该方法能有效的提高检索效率,是一种更为理想的检索方法.     

面向信息检索的快速聚类算法

随着信息检索技术的迅猛发展,针对检索系统的改进已逐渐成为研究的热点.聚类是一种有效的改进策略,通过对检索结果进行聚类,可以使用户快速地定位到自己感兴趣的检索信息所在的类别.然而,传统的检索聚类算法要么运行效率低下,要么类别划分能力不强,使它们无法真正地用于检索系统中.针对此问题,提出了一种新颖的检索聚类算法,该算法首先通过极大极小值理论从检索返回的文档集中抽取多个聚点,并依此形成初始文档类划分结果.在此基础上,算法对初始文档类的特征集合进行细化调整以使类别的划分更加精确;同时对不满足收敛条件的文档类进行层次分裂以解决信息的分层描述问题.实验表明:此算法的时间复杂度与现有的检索聚类技术相差不多,并且由于对特征集合进行迭代调整使得类别的划分更加准确合理.     

DRR:一种多维案例检索优化算法研究

基于本体的案例检索系统中,由于数据库中的案例数量随着时间的推移而成倍增加,案例检索的效率不断降低。提出了一种多维案例检索算法—DRR,该算法通过将多维空间案例点降维成二维空间点,利用一个二维空间点来代表类案例点组成的集合,并对此二维空间点建立R树空间索引,通过两级检索的方法,加速了检索效率和准确率。实验证明,该方法不仅提高了案例检索的准确率,还极大地提高了案例检索的效率。     

一种关系数据库对象级别检索结果的聚类方法

针对关系数据库元组级别关键词检索中存在查询语句多义性及展现结果冗余性等问题,提出一种关系数据库对象级别检索结果的聚类方法。以对象的观点,综合考虑检索结果的相关性和多样性,从结构和内容两个层面对其聚类。基于覆盖树对检索结果进行同构判断,实现第一级聚类;利用核函数计算同构类别中检索结果间所包含内容的相似性,实现第二级聚类;同时对聚类后的结果集进行动态更新。该聚类方法有效降低了展现结果的冗余性,增加了用户可选择的结果类别,提高了检索系统的性能。     

一种有效的用于范例提取的改进聚类算法

针对传统范例提取算法随范例教增加而效率下降快的缺点，结合基于选择的CLARA聚类方法和NCL聚类算法的优点，给出了一种有效的无监督聚类学习算法．通过实验表明，该算法能在无监督下对范例进行准确归类，将它用于CBR的范例提取中，能大大地提高范例提取的速度和质量。     

相似案例自适应选择算法及其应用

为提高相似案例选择的效率和准确性，将有向无环图支持向量机（DAGSVM）多类分类器应用到相似案例选择中．提出多类分类器有效分辨阈值的概念，在保证一定案例选择准确度的前提下．对自适应构造案例集进行相似案例选择．提高相似案例选择的效率．将该方法应用于光动力治疗（PDT）鲜红斑痣（PWS）案例推理专家系统．实验结果表明了该方法的有效性．     

A Multi-Resolution Content-Based Retrieval Approach for Geographic Images

Current retrieval methods in geographic image databases use only pixel-by-pixel spectral information. Texture is an important property of geographical images that can improve retrieval effectiveness and efficiency. In this paper, we present a content-based retrieval approach that utilizes the texture features of geographical images. Various texture features are extracted using wavelet transforms. Based on the texture features, we design a hierarchical approach to cluster geographical images for effective and efficient retrieval, measuring distances between feature vectors in the feature space. Using wavelet-based multi-resolution decomposition, two different sets of texture features are formulated for clustering. For each feature set, different distance measurement techniques are designed and experimented for clustering images in a database. The experimental results demonstrate that the retrieval efficiency and effectiveness improve when our clustering approach is used.     

Transferring Case Knowledge To Adaptation Knowledge: An Approach for Case-Base Maintenance

In this article we propose a case-base maintenance methodology based on the idea of transferring knowledge between knowledge containers in a case-based reasoning (CBR) system. A machine-learning technique, fuzzy decision-tree induction, is used to transform the case knowledge to adaptation knowledge. By learning the more sophisticated fuzzy adaptation knowledge, many of the redundant cases can be removed. This approach is particularly useful when the case base consists of a large number of redundant cases and the retrieval efficiency becomes a real concern of the user. The method of maintaining a case base from scratch, as proposed in this article, consists of four steps. First, an approach to learning feature weights automatically is used to evaluate the importance of different features in a given case base. Second, clustering of cases is carried out to identify different concepts in the case base using the acquired feature-weights knowledge. Third, adaptation rules are mined for each concept using fuzzy decision trees. Fourth, a selection strategy based on the concepts of case coverage and reachability is used to select representative cases. In order to demonstrate the effectiveness of this approach as well as to examine the relationship between compactness and performance of a CBR system, experimental testing is carried out using the Traveling and the Rice Taste data sets. The results show that the testing case bases can be reduced by 36 and 39 percent, respectively, if we complement the remaining cases by the adaptation rules discovered using our approach. The overall accuracies of the two smaller case bases are 94 and 90 percent, respectively, of the originals.     

基于特征加权C均值聚类算法的案例索引和检索

一个成功的案例推理系统高度取决于如何设计出一个精确并且高效的案例检索机制。提出用特征加权C均值聚类算法（WF—C—means）把源案例中的初始案例分成几类。在WF—C—means的分类结果基础上提出了案例索引方案。实验表明,研究的结果对于一个现实的案例推理系统非常有用。     

Customer segmentation issues and strategies for an automobile dealership with two clustering techniques

Companies can use customer segmentation to group customers with similar characteristics together and identify the differences between groups to develop marketing strategies. This study investigates the problem of customer segmentation in relation to automotive customer relationship management and presents a real case study of an automobile dealer in Taiwan. Although several past studies have adopted different clustering techniques with which to group customer attributes, few have simultaneously considered customer transaction behaviour and customer satisfaction variables. In addition, most previous work has used only a single clustering method for customer segmentation, which results in unreliable results and leads to inadequate marketing decisions. Therefore, in this study, we consider two clustering techniques, k‐means and expectation maximization, and compare their results for correctness. The experimental results show that four customer groups are identified with both clustering methods: loyal, potential, VIP and churn customer groups. Based on the segmentation results, several customized marketing strategies aimed at each of the four customer groups are suggested to improve the quality of services for effective customer relationship management.     

一种基于滑动窗口的案例检索算法

在基于K-means的案例检索算法中,目标案例初次映射的失败会导致案例检索成功率降低。针对该问题,提出一种基于滑动窗口的案例检索算法。分析滑动窗口维护策略,利用滑动窗口收集案例库中权重较高且最近常使用的案例,增加案例采样数量。实验结果表明,该算法能提高检索成功率,检索时间较短且案例映射次数较少。     

基于案例推理的信息系统业务流程知识重用技术研究

本文在研究信息系统业务流程设计的知识表示与重用技术的基础上,提出了一种基于案例的智能化设计知识重用方法进行信息系统业务流程设计.重用方法包含案例表示、基于相似度算法和智能聚类的案例检索、案例优化、案例库组织四个方面.综合四个方面,实现了基于案例推理的业务流程案例检索和知识重用实验系统原型,并进行了实验.实验结果表明本重用方法具有较好的可行性、有效性、效率与质量.