Negative sequential pattern mining

University of Technology, Sydney. Faculty of Engineering and Information Technology.Sequential pattern mining provides an important way to obtain special patterns from sequence data. It produces important insights on bioinformatics data, web-logs, customer transaction data, and so on. Different from traditional positive sequential pattern (PSP) mining, negative sequential pattern (NSP) mining takes negative itemsets into account besides positive ones. It would be more interesting in applications where non-occurring itemsets need to be considered. This thesis reports our previous and the latest research outcomes in this area. The contributions of the thesis are as following. • A comprehensive literature review of negative frequent pattern mining is described. • A general framework of the NSP mining is proposed. It can be used to describe the big picture of both PSP and NSP mining problems. • Three innovative algorithms are proposed to mine NSP efficiently. • Extensive experiments about the three algorithms on either synthetic or real-world datasets show that the proposed methods can find NSP efficiently. • A case study describes a real-life application on customer claims analysis in health insurance industry. Three algorithms of NSP mining are proposed in this thesis, listed as below: (1) The first algorithm Neg-GSP (Zheng, Zhao, Zuo & Cao 2009) is based on a PSP mining algorithm GSP (Srikant & Agrawal 1996). Neg-GSP deals with negative problem by introducing new methods of joining and generating candidates, which borrow ideas from GSP algorithm. And also, an effective pruning method to reduce the number of candidates is proposed as well. (2) The second one is a Genetic Algorithm based algorithm (Zheng, Zhao, Zuo & Cao 2010), which is called GA-NSP. It is proposed to find NSP with novel crossover and mutation operations, which are efficient at passing good genes on to next generations. An effective dynamic fitness function and a pruning method are also provided to improve performance. (3) The third algorithm e-NSP (Dong, Zheng, Cao, Zhao, Zhang, Li, Wei & Ou 2011) is based on the Set Theory. It mines NSP by only involving the identified PSP, without re-scanning the database. In this way, mining NSP does not require any additional database scans. It facilitates the existing PSP mining algorithms to mine NSP. It offers a new strategy for efficient mining of NSP. The results of extensive experiments about the three algorithms show that they can find NSP efficiently. They have good performance compared with some other existing NSP mining algorithms, such as PNSP (Hsueh, Lin & Chen 2008). If we compare the problem statements of the above three methods, Neg-GSP and GA-NSP share the same definitions, e-NSP uses stronger constraints since it requires clear boundary to follow the Set Theory. When comparing their performances, GA-NSP algorithm slightly outperforms Neg-GSP in terms of execution time, but it may miss some patterns in the complete result sets due to limitations of Genetic Algorithm. Apparently, e-NSP is the most efficient and effective one since it does not need to scan datasets to calculate the support of NSP. Although adding stronger constraints on e-NSP makes the search space much smaller than what it is under the normal definitions, it is still very practicable while being used in some real-life applications. Following that, NSP mining case studies coming from health insurance industry are introduced. Based on real-life customer claims datasets, we use the proposed NSP mining methods to find PSP and NSP on solving two business issues, one is in ancillary service over-service analysis, another is fraud claim detection. Both of the two case studies demonstrate the benefits gained from mining NSP

Mining Frequent Itemsets Using Genetic Algorithm

In general frequent itemsets are generated from large data sets by applying association rule mining algorithms like Apriori, Partition, Pincer-Search, Incremental, Border algorithm etc., which take too much computer time to compute all the frequent itemsets. By using Genetic Algorithm (GA) we can improve the scenario. The major advantage of using GA in the discovery of frequent itemsets is that they perform global search and its time complexity is less compared to other algorithms as the genetic algorithm is based on the greedy approach. The main aim of this paper is to find all the frequent itemsets from given data sets using genetic algorithm

Encapsulation of Soft Computing Approaches within Itemset Mining a A Survey

Data Mining discovers patterns and trends by extracting knowledge from large databases. Soft Computing techniques such as fuzzy logic, neural networks, genetic algorithms, rough sets, etc. aims to reveal the tolerance for imprecision and uncertainty for achieving tractability, robustness and low-cost solutions. Fuzzy Logic and Rough sets are suitable for handling different types of uncertainty. Neural networks provide good learning and generalization. Genetic algorithms provide efficient search algorithms for selecting a model, from mixed media data. Data mining refers to information extraction while soft computing is used for information processing. For effective knowledge discovery from large databases, both Soft Computing and Data Mining can be merged. Association rule mining (ARM) and Itemset mining focus on finding most frequent item sets and corresponding association rules, extracting rare itemsets including temporal and fuzzy concepts in discovered patterns. This survey paper explores the usage of soft computing approaches in itemset utility mining

Scalable Bayesian modeling, monitoring and analysis of dynamic network flow data

Traffic flow count data in networks arise in many applications, such as automobile or aviation transportation, certain directed social network contexts, and Internet studies. Using an example of Internet browser traffic flow through site-segments of an international news website, we present Bayesian analyses of two linked classes of models which, in tandem, allow fast, scalable and interpretable Bayesian inference. We first develop flexible state-space models for streaming count data, able to adaptively characterize and quantify network dynamics efficiently in real-time. We then use these models as emulators of more structured, time-varying gravity models that allow formal dissection of network dynamics. This yields interpretable inferences on traffic flow characteristics, and on dynamics in interactions among network nodes. Bayesian monitoring theory defines a strategy for sequential model assessment and adaptation in cases when network flow data deviates from model-based predictions. Exploratory and sequential monitoring analyses of evolving traffic on a network of web site-segments in e-commerce demonstrate the utility of this coupled Bayesian emulation approach to analysis of streaming network count data.Comment: 29 pages, 16 figure