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In this paper, we deal with the problem of handling solutions in an external archive with the use of a relaxed form of Pareto dominance called ?-dominance and a variation of it called pa?-dominance. These two relaxed forms of Pareto dominance have been used as archiving strategies in some multi-objective evolutionary algorithms (MOEAs). The main objective of this work is to improve the ?-dominance based schemes to handle nondominated solutions, or to retain nondominated solutions in an external archive. Thus, our main contribution is to add an extra objective function only at the time of accepting a nondominated solution into the external archive, in order to preserve some solutions which are normally lost when using any of the aforementioned relaxed forms of Pareto dominance. Such a proposal is inexpensive (computationally speaking) and quite effective, since it is able to produce Pareto fronts of much better quality than the aforementioned archiving techniques. 相似文献
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《Computer Networks》1999,31(11-16):1495-1507
The Web mostly contains semi-structured information. It is, however, not easy to search and extract structural data hidden in a Web page. Current practices address this problem by (1) syntax analysis (i.e. HTML tags); or (2) wrappers or user-defined declarative languages. The former is only suitable for highly structured Web sites and the latter is time-consuming and offers low scalability. Wrappers could handle tens, but certainly not thousands, of information sources. In this paper, we present a novel information mining algorithm, namely KPS, over semi-structured information on the Web. KPS employs keywords, patterns and/or samples to mine the desired information. Experimental results show that KPS is more efficient than existing Web extracting methods. 相似文献
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自适应网站能够提高网站对用户的服务质量。本文首先给出自适应网站的总体框架,对框架中主要模块做详细的分析,包括数据预处理、数据挖掘、页面推荐和站点调整。在数据挖掘模块给出一种有效的识别用户访问模式的算法,该算法利用数据库查询简化频繁最大前向访问路径集的查找,并在此基础上形成频繁访问路径图,为页面推荐和站点调整做好准备。最后给出自适应网站的设计原则。 相似文献
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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. 相似文献
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It is important to provide long-term preservation of digital data even when those data are stored in an unreliable system such as a filesystem, a legacy database, or even the World Wide Web. In this paper we focus on the problem of archiving the contents of a Web site without disrupting users who maintain the site. We propose an archival storage system, the InfoMonitor, in which a reliable archive is integrated with an unmodified existing store. Implementing such a system presents various challenges related to the mismatch of features between the components such as differences in naming and data manipulation operations. We examine each of these issues as well as solutions for the conflicts that arise. We also discuss our experience using the InfoMonitor to archive the Stanford Database Groups Web site. 相似文献
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HTML文档重复模式挖掘是找到Web页面编码模版的关键,是Web数据自动抽取和Web内容挖掘的基础。传统的基于字符串匹配和树匹配的重复模式挖掘方法虽然具有较高的精确度,但是其性能对于处理海量的Web页面来说仍然是一个挑战。为了提高性能,提出了一种基于缩进轮廓的HTML文档重复模式挖掘方法。该方法首先定义了缩进轮廓模型,是一种由HTML文档每行代码的缩进值及行首的HTML标签构成的数据结构,它是HTML文档的一种简化抽象;该方法通过检测缩进轮廓中的串联重复波段,间接地挖掘HTML文档中的重复模式。实验表明,该方法不但具有较高的精确度,而且较明显地提升了性能。 相似文献
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Hua-Fu Li 《Expert systems with applications》2009,36(8):11304-11311
Online mining of path traversal patterns from continuous Web click streams is one of the challenging research problems of Web usage mining. Most of previous works focus on mining path traversal patterns over the entire history of Web click streams. Mining the recent changes of Web click streams can provide valuable information for the analysis of the Web click streams. In this paper, we propose a new, online mining algorithm, called Top-DSW (top-k path traversal patterns of stream Damped Sliding Window), to discover the set of top-k path traversal patterns from streaming maximal forward references, where k is the desired number of path traversal patterns to be mined. An effective summary data structure, called TKP-DSW-list (a list of top-k path traversal patterns of stream Damped Sliding Windows) is developed to maintain the essential information about the top-k path traversal patterns from the maximal forward references within a stream damped sliding window. An effective space pruning mechanism, called TKR-list-maintain, is developed to control the memory requirement of the TKP-DSW-list. Experimental studies show that the proposed Top-DSW algorithm is an efficient, single-pass algorithm for online mining of the set of top-k path traversal patterns over stream damped sliding windows. 相似文献
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Shashikumar G. Totad R. B. Geeta P. V. G. D. Prasad Reddy 《Knowledge and Information Systems》2012,33(2):475-490
In the present scenario of global economy and World Wide Web, large sets of evolving and distributed data can be handled efficiently by incremental data mining. Frequent patterns are very important in knowledge discovery and data mining process, such as mining of association rules, correlations. FP-tree is a very versatile data structure used for mining of frequent patterns in knowledge discovery and data mining process. FP-tree is a compact representation of transaction database that contains frequency information of all relevant frequent patterns (FP) of the database. All of the existing incremental frequent pattern mining algorithms, such as AFPIM, CATS, CanTree, CP-tree, and SPO-tree, perform incremental mining by processing one transaction of the incremental part of database at a time and updating it to the FP-tree of initial (original) database. Here, in this paper, we propose a novel method that takes advantage of FP-tree representation of incremental transaction database for incremental mining. We propose a batch incremental processing algorithm BIT_FPGrowth that restructures and merges two small consecutive duration FP-trees to obtain a FP-tree of the FP-Growth algorithm. Our BIT_FPGrowth uses FP-tree as preprocessed data repository to get transactions (i.e., item-sets), unlike other sequential incremental algorithms that read transactions from database. BIT_FPGrowth algorithm takes less time for constructing FP-tree. Our experimental results show that, as the size of the database increases, increase in runtime of BIT_FPGrowth is much less and is least of all the other algorithms. 相似文献
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Web的数据挖掘 总被引:1,自引:0,他引:1
李健 《数字社区&智能家居》2006,(32)
文章主要描述了WEB页数据挖掘的基本任务,包括内容、结构、使用等。针对Web数据的复杂性和特殊性,Web的数据挖掘除日志等一小部分可以用常用的数据挖掘方法外,必须对Web页做必要的数据处理,使之达到结构化数据的挖掘要求,或使用XML技术来构造半结构数据模式再进行数据挖掘。 相似文献
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Frequent Web navigation patterns generated by using Web usage mining techniques provide valuable information for several applications
such as Web site restructuring and recommendation. In conventional Web usage mining, semantic information of the Web page
content does not take part in the pattern generation process. In this work, we investigate the effect of semantic information
on the patterns generated for Web usage mining in the form of frequent sequences. To this aim, we developed a technique and
a framework for integrating semantic information into Web navigation pattern generation process, where frequent navigational
patterns are composed of ontology instances instead of Web page addresses. The quality of the generated patterns is measured
through an evaluation mechanism involving Web page recommendation. Experimental results show that more accurate recommendations
can be obtained by including semantic information in navigation pattern generation, which indicates the increase in pattern
quality. 相似文献
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Data Preparation for Mining World Wide Web Browsing Patterns 总被引:8,自引:0,他引:8
The World Wide Web (WWW) continues to grow at an astounding rate in both the sheer volume of traffic and the size and complexity of Web sites. The complexity of tasks such as Web site design, Web server design, and of simply navigating through a Web site have increased along with this growth. An important input to these design tasks is the analysis of how a Web site is being used. Usage analysis includes straightforward statistics, such as page access frequency, as well as more sophisticated forms of analysis, such as finding the common traversal paths through a Web site. Web Usage Mining is the application of data mining techniques to usage logs of large Web data repositories in order to produce results that can be used in the design tasks mentioned above. However, there are several preprocessing tasks that must be performed prior to applying data mining algorithms to the data collected from server logs. This paper presents several data preparation techniques in order to identify unique users and user sessions. Also, a method to divide user sessions into semantically meaningful transactions is defined and successfully tested against two other methods. Transactions identified by the proposed methods are used to discover association rules from real world data using the WEBMINER system [15]. 相似文献
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针对制丝生产线工序流程复杂,需要监控的工艺指标多,为提高监控的全面性和准确度,减少生产中由于质量缺陷带来的损失,采用Web技术对每一道工序的工艺指标进行在线监控和超限提醒。通过Web网页实时访问制丝生产数据采集系统,获得各项工序段的生产数据,监控网页将获得的数据生成相应的趋势图,同时监控工艺指标是否满足设定值,并通过语音对监控人员进行提醒。结果表明,监控人员可以在一个Web网页上浏览所有工序的实时生产状况,当制丝生产出现异常,听到语音提示后能迅速确定异常工序段,及时避免质量缺陷带来的损失。该系统应用于长城雪茄烟厂的制丝生产线中,有效减少了生产中的断料次数,提高了烟丝生产的质量。 相似文献
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Most work on pattern mining focuses on simple data structures such as itemsets and sequences of itemsets. However, a lot of recent applications dealing with complex data like chemical compounds, protein structures, XML and Web log databases and social networks, require much more sophisticated data structures such as trees and graphs. In these contexts, interesting patterns involve not only frequent object values (labels) appearing in the graphs (or trees) but also frequent specific topologies found in these structures. Recently, several techniques for tree and graph mining have been proposed in the literature. In this paper, we focus on constraint-based tree pattern mining. We propose to use tree automata as a mechanism to specify user constraints over tree patterns. We present the algorithm CoBMiner which allows user constraints specified by a tree automata to be incorporated in the mining process. An extensive set of experiments executed over synthetic and real data (XML documents and Web usage logs) allows us to conclude that incorporating constraints during the mining process is far more effective than filtering the interesting patterns after the mining process. 相似文献
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简单的、可扩展的、基于脚本的科学数据处理存档系统S4PA,是NASA Goddard地球科学数据和信息服务中心分布式数据存档中心GES DISC DAAC近年发展和使用的、进行气象卫星遥感数据处理和存储管理的系统。本文全面介绍了S4PA的发展历程、建设原则、系统设计和技术特点。其核心思想是采用成熟技术对气象卫星数据处理和存储进行流程化设计,使资源有效利用率达到最优。S4PA的成功应用,证明了这是一种先进的、低成本的、稳定的、可扩展的数据处理和存档系统。本文有助于将国际先进的数据存档技术应用于我国海量数据的数据处理和存档、数据管理的实际工作中。 相似文献