基于Web访问信息的用户兴趣迁移模式的研究

针对用户浏览网页的兴趣会随时间而变化这一现象,设计了一种网络用户兴趣迁移模式的挖掘模型。把用户的访问兴趣通过隐马尔可夫模型抽象成一种时间序列,以此反映用户兴趣的序列性,进而利用GSP算法从用户兴趣序列中挖掘出用户兴趣的迁移模式。实验证明该方法是有效的,从时间属性上更深层次地描述了用户兴趣的变化情况。     

基于隐马尔可夫模型的电子商务网站结构优化*

针对电子商务网站中部分商品页面不处于用户预期位置,导致用户访问代价较大的情况,提出一种使用隐马尔可夫模型对网站结构进行优化建模的方法。首先建立一个隐马尔可夫模型用于模拟用户带有目的(表现为某种目标商品)的访问过程,再使用该模型挖掘出用户隐藏在访问序列中的目的,最后通过新增超链接实现网站结构优化。实验证明用该方法解决网站结构优化问题具备一定的可行性和有效性。     

基于隐半马尔可夫模型的用户兴趣特征提取

针对网络用户兴趣行为特征的抽取,提出了一种基于隐半马尔可夫模型的用户兴趣特征提取模型,通过用状态驻留时间的概率来控制用户浏览行为,使描述兴趣特征的隐状态和时间的相关性更紧密地结合起来,并且根据隐半马尔可夫模型可以产生多观察值序列的特性,把文本信息划分成多个文本块子区域,使每个子区域的特征和其中一个观察值序列对应起来。实验结果表明,利用隐半马尔可夫模型进行特征提取比HMM方法有更高的准确率和召回率。     

门户个性化兴趣获取与迁移模式发现

个性化服务技术为门户平台上的兴趣挖掘研究带来了新的挑战,如何隐式地获取门户用户兴趣行为以及发现兴趣迁移模式是其中的重要课题.在对门户个性化兴趣映射描述的基础上,提出了一种独立于门户平台的含隐私保护的门户个性化兴趣获取机制,可实现不同兴趣访问行为的隐式获取以及操作语义分析,并采用兴趣扩展规则描述方式进行了隐私保护.结合门户个性化兴趣影响以及兴趣目的预测,给出了带有门户个性化兴趣描述的隐Markov模型扩展,可用于发现不同用户的门户个性化兴趣迁移模式.最后通过验证实验给出了有效性和可行性的结论分析.     

基于隐马尔可夫模型的符号序列自组织聚类

本文提出一种基于模型的、适合变长符号序列的自组织聚类算法。隐马尔可夫模型被用于表达各个聚类，批处理自组织特征被用于符号序列的聚类过程。实验结果表明该算法能有效发现变长符号序列中的聚类模式。     

基于隐式马尔可夫链的基因发现模型和算法

探讨了隐式马尔可夫链在基因发现中的应用。提出了一个基于GHMM(泛化的隐式马尔可夫链)的基因发现系统的简化的模型，论述了用该模型和扩展的Viterbi算法发现基因的方法，介绍了用于描述编码区和非编码区及信号的模型和实现。     

基于曲线波隐马尔可夫模型的人脸检测

提出了一种基于曲线波隐马尔可夫模型的混合人脸检测算法.曲线波变换是一种多尺度几何变换,具有很好的方向性,能用极少的非零系数精确表示图像的边缘,是一种最稀疏的表示方法.根据隐马尔可夫模型对人脸拓扑结构的约束,采用3状态的隐马尔可夫模型进行从粗到细的人脸检测.实验结果表明,这种算法具有较好的检测速度与正确率及鲁棒性.     

基于隐马尔可夫的系统入侵检测方法

针对入侵检测中普遍存在误报与漏报过高的问题,本文提出一种新的基于隐马尔可夫模型的系统入侵检测方法。该方法以程序正常执行过程中产生的系统调用序列为研究对象,首先建立计算机运行状况的隐马尔可夫模型,然后在此模型的基础上提出一个用于计算机系统实时异常检测的算法。实验证明,用这种方法建模的系统在不影响检测率的情况下,比传统的数据建设模节省存储空间,并且准确率高。     

隐半马尔可夫模型在剩余寿命预测中的应用

剩余寿命预测是作出正确的状态维修决策的基础和前提,是设备退化状态识别的重要内容。隐马尔可夫模型（HMM）是一种具有较强模式分类能力的统计分析算法,但是它不能直接用于剩余寿命的预测,而且考虑到隐马尔可夫模型的局限性和剩余寿命预测模型的可解释性,应用隐半马尔可夫模型（HSMM）进行建模和预测。针对HSMM的训练算法极易陷人局部极值点的问题,提出了基于改进微粒群优化算法（MPSO）进行修正。实验结果证明了该方法在设备剩余寿命预测研究上的有效性和可行性。     

基于隐马尔可夫模型和免疫粒子群优化的多序列比对算法

序列的多重比对是生物序列分析研究中的一个重要内容．基于免疫系统的疫苗接种和受体编辑模型，结合粒子群优化方法提出了一种免疫粒子群优化算法，将该算法用于隐马尔可夫模型的学习过程，进而构建了一种基于隐马尔可夫模型和免疫粒子群优化的多序列比对算法，从BAliBASE比对数据库中选取了一些比对例子进行了模拟计算，并与Baum-Welch算法进行了比较．结果表明，所提出的方法不仅提高了比对的准确程度，而且缩减了比对所花费的时间。     

一种Web挖掘的框架

随着Web信息量的增长，Web用户也迅速增长，如何在海量信息中找出用户需要的信息变得更加重要。基于Web服务器日志，分析在线用户的浏览行为，挖掘Web数据并找出用户的遍历模式已经成为一个新的研究领域。针对Web站点的结构，给出了一个Web挖掘的完整框架，允许在分析复杂的遍历模式时加入约束条件，然后对框架中算法的执行效率和执行准确性进行比较和分析，同时展望了Web挖掘的未来研究方向。     

Mining Web navigation patterns with a path traversal graph

Understanding the navigational behaviour of website visitors is a significant factor of success in the emerging business models of electronic commerce and even mobile commerce. However, Web traversal patterns obtained by traditional Web usage mining approaches are ineffective for the content management of websites. They do not provide the big picture of the intentions of the visitors. The Web navigation patterns, termed throughout-surfing patterns (TSPs) as defined in this paper, are a superset of Web traversal patterns that effectively display the trends toward the next visited Web pages in a browsing session. TSPs are more expressive for understanding the purposes of website visitors. In this paper, we first introduce the concept of throughout-surfing patterns and then present an efficient method for mining the patterns. We propose a compact graph structure, termed a path traversal graph, to record information about the navigation paths of website visitors. The graph contains the frequent surfing paths that are required for mining TSPs. In addition, we devised a graph traverse algorithm based on the proposed graph structure to discover the TSPs. The experimental results show the proposed mining method is highly efficient to discover TSPs.     

Mining preferred navigation patterns by consolidating both selection and time preferences

Preferred navigation patterns (PNP) are those contiguous sequential patterns whose elements are preferred by users to be selected as the next steps between several different selections and are preferred by users to spend much time on. Such navigation path and time preferred patterns are more actionable than any other finds only considering either path or time in various web applications, such as web user navigation, targeted online advertising and recommendation. However, due to the conceptual confusion and limitation on navigation preference in the existing work, the corresponding algorithms cannot discover actionable preferred navigation patterns. In this paper, we study the problem of preferred navigation pattern mining by involving both navigation path and time length. Firstly, we carefully define the concepts of time preference and selection preference for time-related path sequences, which can well reflect user interests from the relative path selection and time consumption respectively. Secondly, we propose an efficient PNP-forest algorithm for identifying PNPs, by first introducing PNP-forest data structure, and then presenting PNP-forest growth and maintenance mechanism, associated with optimization strategies. Then we introduce a more efficient mining algorithm called PrefixSpan_Forest, which integrates the advantages of PrefixSpan and PNP-forest. The performance of these two algorithms are also evaluated and the results show that the algorithms can discover PNPs effectively.     

Model-Based Clustering and Visualization of Navigation Patterns on a Web Site

We present a new methodology for exploring and analyzing navigation patterns on a web site. The patterns that can be analyzed consist of sequences of URL categories traversed by users. In our approach, we first partition site users into clusters such that users with similar navigation paths through the site are placed into the same cluster. Then, for each cluster, we display these paths for users within that cluster. The clustering approach we employ is model-based (as opposed to distance-based) and partitions users according to the order in which they request web pages. In particular, we cluster users by learning a mixture of first-order Markov models using the Expectation-Maximization algorithm. The runtime of our algorithm scales linearly with the number of clusters and with the size of the data; and our implementation easily handles hundreds of thousands of user sessions in memory. In the paper, we describe the details of our method and a visualization tool based on it called WebCANVAS. We illustrate the use of our approach on user-traffic data from msnbc.com.     

Incremental and interactive mining of web traversal patterns

Web mining involves the application of data mining techniques to large amounts of web-related data in order to improve web services. Web traversal pattern mining involves discovering users’ access patterns from web server access logs. This information can provide navigation suggestions for web users indicating appropriate actions that can be taken. However, web logs keep growing continuously, and some web logs may become out of date over time. The users’ behaviors may change as web logs are updated, or when the web site structure is changed. Additionally, it can be difficult to determine a perfect minimum support threshold during the data mining process to find interesting rules. Accordingly, we must constantly adjust the minimum support threshold until satisfactory data mining results can be found.The essence of incremental data mining and interactive data mining is the ability to use previous mining results in order to reduce unnecessary processes when web logs or web site structures are updated, or when the minimum support is changed. In this paper, we propose efficient incremental and interactive data mining algorithms to discover web traversal patterns that match users’ requirements. The experimental results show that our algorithms are more efficient than other comparable approaches.     

Prediction of user navigation patterns by mining the temporal web usage evolution

Advances in the data mining technologies have enabled the intelligent Web abilities in various applications by utilizing the hidden user behavior patterns discovered from the Web logs. Intelligent methods for discovering and predicting user’s patterns is important in supporting intelligent Web applications like personalized services. Although numerous studies have been done on Web usage mining, few of them consider the temporal evolution characteristic in discovering web user’s patterns. In this paper, we propose a novel data mining algorithm named Temporal N-Gram (TN-Gram) for constructing prediction models of Web user navigation by considering the temporality property in Web usage evolution. Moreover, three kinds of new measures are proposed for evaluating the temporal evolution of navigation patterns under different time periods. Through experimental evaluation on both of real-life and simulated datasets, the proposed TN-Gram model is shown to outperform other approaches like N-gram modeling in terms of prediction precision, in particular when the web user’s navigating behavior changes significantly with temporal evolution.     

Mining Navigation Patterns Using a Sequence Alignment Method

In this article, a new method is illustrated for mining navigation patterns on a web site. Instead of clustering patterns by means of a Euclidean distance measure, in this approach users are partitioned into clusters using a non-Euclidean distance measure called the Sequence Alignment Method (SAM). This method partitions navigation patterns according to the order in which web pages are requested and handles the problem of clustering sequences of different lengths. The performance of the algorithm is compared with the results of a method based on Euclidean distance measures. SAM is validated by means of user-traffic data of two different web sites. Empirical results show that SAM identifies sequences with similar behavioral patterns not only with regard to content, but also considering the order of pages visited in a sequence.     

蚁群算法在Web站点导航中的应用研究

Web站点导航是Web数据挖掘的一个重要研究领域,是准确理解用户访问网站行为的关键;传统Web站点导航技术很难全面反映出用户对页面浏览的兴趣程度,找到用户感兴趣页面路径准确度比较低;为提高找到用户感兴趣页面路径准确度,提出一种基于蚁群算法的Web站点导航技术;将网络用户看作人工的蚂蚁,用户的浏览兴趣作蚂蚁的信息素,通过利用Web日志数据采用正负反馈机制和路径概率选择机制建立一个Web站点导航模型,挖掘用户感兴趣页面的导航路径;仿真实验结果表明,基于蚁群算法的Web站点导航技术提高了找到用户感兴趣页面路径准确度,更加能够准确反映出用户的浏览兴趣,用于Web站点导航是可行的。