Mining sequential patterns with periodic wildcard gaps

Closed frequent similar pattern mining: Reducing the number of frequent similar patterns without information loss

Frequent pattern mining is a classic data mining technique, generally applicable to a wide range of application domains, and a mature area of research. The fundamental challenge arises from the combinatorial nature of frequent itemsets, scaling exponentially with respect to the number of unique items. Apriori-based and FPTree-based algorithms have dominated the space thus far. Initial phases of this research relied on the Apriori algorithm and utilized a distributed computing environment; we proposed the Cartesian Scheduler to manage Apriori's candidate generation process. To address the limitation of bottom-up frequent pattern mining algorithms such as Apriori and FPGrowth, we propose the Frequent Hierarchical Pattern Tree (FHPTree): a tree structure and new frequent pattern mining paradigm. The classic problem is redefined as frequent hierarchical pattern mining where the goal is to detect frequent maximal pattern covers. Under the proposed paradigm, compressed representations of maximal patterns are mined using a top-down FHPTree traversal, FHPGrowth, which detects large patterns before their subsets, thus yielding significant reductions in computation time. The FHPTree memory footprint is small; the number of nodes in the structure scales linearly with respect to the number of unique items. Additionally, the FHPTree serves as a persistent, dynamic data structure to index frequent patterns and enable efficient searches. When the search space is exponential, efficient targeted mining capabilities are paramount; this is one of the key contributions of the FHPTree. This dissertation will demonstrate the performance of FHPGrowth, achieving a 300x speed up over state-of-the-art maximal pattern mining algorithms and approximately a 2400x speedup when utilizing FHPGrowth in a distributed computing environment. In addition, we allude to future research opportunities, and suggest various modifications to further optimize the FHPTree and FHPGrowth. Moreover, the methods we offer will have an impact on other data mining research areas including contrast set mining as well as spatial and temporal mining.

Sequential pattern mining is a challenging problem that has received much attention in the past few decades. The mining of large sequential databases can be very time consuming and produces a large number of unrelated patterns that must be evaluated. In this paper, we explore the problems of frequent prefix, prefix-closed, and prefix-maximal pattern mining along with their suffix variants. By constraining the pattern mining task, we are able to reduce the mining time required while obtaining patterns of interest. We introduce notations related to prefix/suffix sequential pattern mining while providing theorems and proofs that are key to our proposed algorithms. We show that the use of projected databases can greatly reduce the time required to mine the complete set of frequent prefix/suffix patterns, prefix/suffix-closed patterns, and prefix/suffix-maximal patterns. Theoretical analysis shows that our approach is better than the current existing approach, and empirical analysis on various datasets is used to support these conclusions.

Frequent pattern mining is a basic problem in data mining and knowledge discovery. The discovered patterns can be used as the input for analyzing association rules, mining sequential patterns, recognizing clusters, and so on. However, discovering frequent patterns in large scale datasets is an extremely time consuming task. Most research in the area of association rule discovery has focused on the method of efficient frequent pattern discovery, e.g. Park, Chen & Yu (1995); Savasere, Omiecinski & Navathe (1995); Han, Pei & Yin (2000); Pei, Han, Lu, Nishio, Tang & Yang (2001). When seeking all associations that satisfy constraints on support and confidence, once frequent patterns have been identified, generating the association rules is trivial. In the last decade, various algorithms have been proposed on this problem, e.g. maximal pattern mining - Grahne & Zhu (2003); closed pattern mining - Pei, Han & Mao (2000); Grahne & Zhu (2003); mining the most interesting frequent patterns - Fu, Kwong & Tang (2000); Han, Wang, Lu & Tzvetkov (2002, 2005); Hirate, Iwahashi & Yamana (2004). However, some challenges are still existed and need to be overcome. In this paper, a mathematical space will be introduced with some new related concepts and propositions to design a new algorithm for solving frequent patterns mining problem. It is hoped that such an improved algorithm will be simple to implement and more efficient.

Similarity analysis of frequent sequential activity pattern mining

Sequential pattern mining is a technique which finds out frequent patterns from the data set with a time attribute. Dynamic weighted sequential pattern mining can be applied to a computing environment that is constantly changed according to time period and it can be applied to a variety of environments with changes of weight value. In this paper, we propose a new sequential pattern mining method to discover frequent sequential patterns by applying the dynamic weight. This method reduces the number of candidate patterns by dynamic weight according to the relative time sequence. This also decreases the memory usage and processing time compared with existing methods. And we show the importance of processing USN (Ubiquitous Sensor Network) stream data with hash map structure and the method of renewing current frequent pattern list.

Computer Systems are exposed to an increasing number of different types of security threats due to the expanding of internet in recent years. How to detect network intrusions effectively becomes an important security technique. Many intrusions aren't composed by single events, but by a series of attack steps taken in chronological order. Analyzing the order in which events occur can improve the attack detection accuracy and reduce false alarms. Intrusion is a multi step process in which a number of events must occur sequentially in order to launch a successful attack. Intrusion detection using sequential pattern mining is a research topic focusing on the field of information security. Sequential Pattern Mining is used to discover the frequent sequential pattern in the event dataset. Sequential Pattern mining algorithms can be broadly classified into Apriori based, Pattern growth based and a combination of both. The first algorithm is based on the characteristic of Apriori and the second uses a pattern growth approach. The major drawback of the Apriori based algorithm is the multiple scans of the database, generating maximal patterns. In this paper, a simulation study of both the algorithms, a modified AprioriALL Algorithm to optimize the processing by including set theory techniques and the original AprioriALL algorithm is done on a network intrusion dataset from KDD cup 1999. Experimental results show that the modified algorithm shrinks the dataset size. At the most, it also scans the database twice. Also, as the interestingness of the itemset is increased with the dataset shrinking it leads to efficient sequences with high associativity. As the database is reduced, the time taken to mine sequences also reduces and is faster than Apriori based algorithm.

Recent research in frequent pattern mining (FPM) has shifted from obtaining the complete set of frequent patterns to generating only a representative (summary) subset of frequent patterns. Most of the existing approaches to this problem adopt a two-step solution; in the first step, they obtain all the frequent patterns, and in the second step, some form of clustering is used to obtain the summary pattern set. However, the twostep method is inefficient and sometimes infeasible since the first step itself may fail to finish in a reasonable amount of time. In this paper, we propose an alternative approach to mining frequent pattern representatives based on a uniform sampling of the output space. Our new algorithm, Musk, obtains representative patterns by sampling uniformly from the pool of all frequent maximal patterns; uniformity is achieved by a variant of Markov Chain Monte Carlo (MCMC) algorithm. Musk simulates a random walk on the frequent pattern partial order graph with a prescribed transition probability matrix, whose values are computed locally during the simulation. In the stationary distribution of the random walk, all maximal frequent pattern nodes in the partial order graph are sampled uniformly. Experiments on various kind of graph and itemset databases validate the effectiveness of our approach.

One of the sub areas of the data mining includes sequential pattern mining. This mining algorithm is to find the repeating patterns after mining the sequence databases. These are used to find the relation between the various items in the data for different purposes. As these data keep changing according to the change in time, mining should be done on incremented or updated database to obtain the frequent sequential patterns. The proposed algorithm in this paper uses modified algorithm of sequential pattern mining including concepts of fuzzy space intervals. In this algorithm, frequently occurring sequential patterns in the sequence database are mined using apriori like method. Fuzzy theory is used for mining the space interval between the frequently occurring sequences. The sequentially occurring candidate patterns are found first. After that follows the frequently occurring sequential patterns, which are found by calculating the minimum fuzzy support along with the use of the fuzzy number. Each space cluster is found by fuzzy support computation. The final results comprises the frequently occurring fuzzy space sequentially based patterns. At last the outcome also confirms the excellence of the suggested MISPFSI algorithm.

BackgroundMany studies report about detection and functional characterization of cis-regulatory motifs in untranslated regions (UTRs) of mRNAs but little is known about the nature and functional role of their distribution. To address this issue we have developed a computational approach based on the use of data mining techniques. The idea is that of mining frequent combinations of translation regulatory motifs, since their significant co-occurrences could reveal functional relationships important for the post-transcriptional control of gene expression. The experimentation has been focused on targeted mitochondrial transcripts to elucidate the role of translational control in mitochondrial biogenesis and function.ResultsThe analysis is based on a two-stepped procedure using a sequential pattern mining algorithm. The first step searches for frequent patterns (FPs) of motifs without taking into account their spatial displacement. In the second step, frequent sequential patterns (FSPs) of spaced motifs are generated by taking into account the conservation of spacers between each ordered pair of co-occurring motifs. The algorithm makes no assumption on the relation among motifs and on the number of motifs involved in a pattern. Different FSPs can be found depending on different combinations of two parameters, i.e. the threshold of the minimum percentage of sequences supporting the pattern, and the granularity of spacer discretization. Results can be retrieved at the UTRminer web site: . The discovered FPs of motifs amount to 216 in the overall dataset and to 140 in the human subset. For each FP, the system provides information on the discovered FSPs, if any. A variety of search options help users in browsing the web resource. The list of sequence IDs supporting each pattern can be used for the retrieval of information from the UTRminer database.ConclusionComputational prediction of structural properties of regulatory sequences is not trivial. The presented data mining approach is able to overcome some limits observed in other competitive tools. Preliminary results on UTR sequences from nuclear transcripts targeting mitochondria are promising and lead us to be confident on the effectiveness of the approach for future developments.

It has been well recognized that frequent pattern mining plays an essential role in many important data mining tasks. However, frequent pattern mining often generates a very large number of patterns and rules, which reduces not only the efficiency but also the effectiveness of mining. Recent work has highlighted the importance of the constraint-based mining paradigm in the context of mining frequent itemsets, associations, correlations, sequential patterns, and many other interesting patterns in large databases.Recently, we developed efficient pattern-growth methods for frequent pattern mining. Interestingly, pattern-growth methods are not only efficient but also effective in mining with various constraints. Many tough constraints which cannot be handled by previous methods can be pushed deep into the pattern-growth mining process. In this paper, we overview the principles of pattern-growth methods for constrained frequent pattern mining and sequential pattern mining. Moreover, we explore the power of pattern-growth methods towards mining with tough constraints and highlight some interesting open problems.

In this paper, we focus on frequent pattern mining using non Boolean similarity functions Several properties and propositions that allow pruning the search space of frequent similar patterns, are proposed Based on these properties, an algorithm for mining frequent similar patterns using non Boolean similarity functions is also introduced We evaluate the quality of the frequent similar patterns computed by our algorithm by means of a supervised classifier based on frequent patterns.

High volumes of wide varieties of valuable data of different veracities can be easily generated or collected at a high velocity from various big data applications and services. Embedded in these big data are valuable knowledge and useful information, which can be discovered by data science solutions. As a popular data science task, frequent pattern mining aims to discover implicit, previously unknown and potentially useful information and valuable knowledge in terms of sets of frequently co-occurring items. Many of the existing frequent pattern mining algorithms return large numbers of frequent patterns, of which only a small portion may be of interest to users. In this paper, we present a constrained mining algorithm that allows crowds of users to collaboratively vote for their interesting patterns. Such an algorithm takes the benefits of crowdsourcing, crowdvoting and collaborative filtering for the data analytics and mining of popular constrained frequent patterns from big data applications and services.

Clinical research has led to the development of new medications and medication strategy may change to gain better treatment outcomes. With the increasing attention to the evidence based medical guideline, it is important for clinicians to study the medication strategy changes. This study is interested in evaluating long-term prescriptions of type 2 diabetes patients provided by Kyoto University Hospital following the release of a new medication in 2010. Frequent sequential pattern mining (FSPM) is a prominent tools for extracting frequent patterns. However, the number of the result set could be enormous and may inhibit clinicians in assessing the results. To help the clinicians, a medication progression graph (MPG) is constructed using adjacent (1-sequence) frequent patterns produced by the singleton pattern mining. Compared to conventional frequent patterns, singleton's patterns features full itemsets and 1-step distance. Hence, the pattern represents the true medication transition event. Using the graph, a clinical physician was able to observe a significant increase of physician's activities in changing the medication after the release (i.e., in MPG that start with Sulfonylurea after 2010, the number of edges is increase by 2.83 and the number of nodes is increase by 2.27 compared to before 2010). Our preliminary results show that the new visualization method enables a clinician to analyze a medication strategy changes after the new medication released.

Sequential pattern mining is an important mining task for discovering sequential patterns along with their insight relationships in many real-world applications. In practice, sequence databases are kept changing over the time along with their business. For some reasons, some sequences in the database are asked to be deleted from the database. In order to have a synchronization of discovered sequential patterns with the database from which they have been discovered, the sequential pattern mining task is re-considered with many challenges. As the number of deleted sequences is often smaller than the size of the entire database, re-mining from scratch the updated database might incur a high cost because sequential pattern mining is a computationally expensive task. In this paper, our work aims at an efficient incremental mining solution to the sequential pattern mining task with sequence deletions. Different from the existing works, we propose an expanded prefix tree by extending the existing prefix tree with additional structures for capturing more necessary information for the incremental mining process. Based on this tree, we propose an incremental sequential pattern mining algorithm, SPMD, for finding a complete set of sequential patterns with no re-scanning the original database, when a number of sequences in the database are deleted. Experimental results on the benchmark databases have confirmed that our SPMD algorithm outperforms the re-mining from scratch with the PrefixSpan algorithm with less running time.