High Average-utility Itemset Mining Research Articles

Maintenance algorithm for high average-utility itemsets with transaction deletion

High-utility itemset mining (HUIM) is an extension of traditional association-rule mining that can find profitable itemsets for decision-making. It faces, however, a limitation since the utility of an itemset increases along with the size of it. High-average utility itemset mining (HAUIM) provides a fair measure to find the average-utility of an itemset, which is more reasonable to design the sales strategies for making the efficient decision. Traditional algorithms of HAUIM mostly focus on mining high average-utility itemsets (HAUIs) from the static database. When the database size is changed, for example, transaction insertion/deletion, the discovered information is required to be updated, thus the updated database is necessary to be re-scanned for identifying the set of HAUIs in the batch manner. In this paper, we present an updating algorithm called FUP-HAUIMD to maintain the discovered HAUIs with transaction deletion. When some transactions in the database are deleted, the designed FUP-HAUIMD algorithm can easily update the discovered HAUIs without scanning the database all the time. The designed FUP-HAUIMD algorithm divides the itemsets into four cases based on the modified fast updated (MFUP) concept. The average-utility (AU)-list structure is further utilized to keep the necessary ramification for later mining progress. Experiments are then conducted to compare the designed FUP-HAUIMD algorithm with the state-of-the-art baseline algorithm running on the batch mode, and the developed approach shows better performance in terms of runtime, number of examined patterns, and scalability.

Efficiently updating the discovered high average-utility itemsets with transaction insertion

High-utility itemset mining (HUIM) is an extension of frequent-itemset mining (FIM) but considers the unit profit and quantity of items to discover the set of high-utility itemsets (HUIs). Traditionally, the utility of an itemset is the summation of the utilities of the itemset in all the transactions regardless of its length. This approach is, however, inappropriate in real-world applications since the utility of the itemset increases along with the number of items within it. High average-utility itemset mining (HAUIM) was designed to provide more reasonable utility measure by taking the size of the itemset into account. Existing algorithms can only handle, however, the static database and unsuitable for the dynamic environment since the size of data is frequently changed in real-life situations. In this paper, an incremental high-average utility pattern mining (IHAUPM) algorithm is presented to handle the incremental database with transaction insertion. The well-known fast updated (FUP) concept in the FIM is modified to adopt the designed algorithm, thus efficiently updating the discovered HAUIs. Based on the designed model for HAUIM with transaction insertion, the proposed IHAUPM algorithm can easily only handle the inserted transactions. Experiments are carried on six datasets and the results showed that the designed algorithm has better performance than the state-of-the-art algorithms performing in the batch manner.

Top-k high average-utility itemsets mining with effective pruning strategies

High average-utility itemset (HAUI) mining has recently received interest in the data mining field due to its balanced utility measurement, which considers not only profits and quantities of items but also the lengths of itemsets. Although several algorithms have been designed for the task of HAUI mining in recent years, it is hard for users to determine an appropriate minimum average-utility threshold for the algorithms to work efficiently and control the mining result precisely. In this paper, we address this issue by introducing a framework of top-k HAUI mining, where \(k\) is the desired number of high average-utility itemsets to be mined instead of setting a minimum average-utility threshold. An efficient list based algorithm named TKAU is proposed to mine the top-k high average-utility itemsets in a single phase. TKAU introduces two novel strategies, named EMUP and EA to avoid performing costly join operations for calculating the utilities of itemsets. Moreover, three strategies named RIU, CAD, and EPBF are also incorporated to raise its internal minimal average-utility threshold effectively, and thus reduce the search space. Extensive experiments on both real and synthetic datasets show that the proposed algorithm has excellent performance and scalability.

TUB-HAUPM: Tighter Upper Bound for Mining High Average-Utility Patterns

High-utility itemset mining (HUIM) has been gaining popularity in the field of data mining. Frequent itemset mining used to be the main tool to reveal high-frequency patterns but failed to consider the concept of profit. HUIM, on the other hand, obtains the itemsets and is practical in commercial applications. A main challenge in HUIM is that HUIM should handle the exponential search space for HUIM when the number of distinct items and the size of the database are both too large. The other challenge is that existing HUIM methods overlook the length of high-utility itemsets; hence, a large itemset gets an unreasonable estimated profit as opposed to the actual value. Therefore, several algorithms were proposed to mine high average-utility itemsets. High average-utility itemset mining (HAUIM) is an extension for the traditional HUIM, which provides a different measure with HUIM. It discovers utility patterns by considering both their utilities and lengths. To reduce the searching space in HAUIM, average-utility upper-bound, looser upper-bound utility, and a revised tighter upper-bound model are proposed to prune the searching graph in HAUIM. These three upper-bounds for high average-utility itemsets decrease the number of candidate patterns efficiently. However, they still overestimate a high average-utility itemset and waste on assessing the unnecessary patterns. Two new tighter upper-bounds, maximum following utility upper-bound and top-k transaction-maximum utility upper-bound, are proposed in this paper to further contract the size of candidate pattern set. Experiments conducted on several benchmark data sets show that the proposed method outperforms the previous HAUIM algorithms in terms of runtime, the number of join operations, and scalability.

MEMU: More Efficient Algorithm to Mine High Average-Utility Patterns With Multiple Minimum Average-Utility Thresholds

High average-utility itemsets mining (HAUIM) is an emerging topic in data mining. Compared to traditional high utility itemset mining, HAUIM more fairly measures the utility of itemsets by considering their lengths (number of items). Many previous studies have presented algorithms to efficiently mine high average-utility itemsets (HAUIs). Most of these algorithms, however, only mine HAUIs using a single minimum high average-utility threshold, which limits their usefulness to analyze real data. This is a problem because different items are not equally important to the user. The importance of an item can be expressed for example in terms of weights, interestingness or unit profit. In the past, a baseline algorithm called HAUIM-MMAU was presented to mine HAUIs using multiple minimum high average-utility thresholds. However, it uses a generate-and-test approach to mine HAUIs using a level-wise approach, which is time consuming. In this paper, we propose an efficient algorithm to discover HAUIs based on the average-utility list structure. A tighter upper-bound model is used to reduce the search space instead of the one used in traditional HAUIM, which is called the auub model. Three pruning strategies are also respectively developed to increase the performance HAUIs. Experiments show that the proposed algorithm outperforms the state-of-the-art HAUIM-MMAU algorithm in terms of runtime, memory usage, number of candidates, and scalability.

A fast algorithm for mining high average-utility itemsets

Mining high-utility itemsets (HUIs) in transactional databases has become a very popular research topic in recent years. A popular variation of the problem of HUI mining is to discover high average-utility itemsets (HAUIs), where an alternative measure called the average-utility is used to evaluate the utility of itemsets by considering their lengths. Albeit, HAUI mining has been studied extensively, current algorithms often consume a large amount of memory and have long execution times, due to the large search space and the usage of loose upper bounds to estimate the average-utilities of itemsets. In this paper, we present a more efficient algorithm for HAUI mining, which includes three pruning strategies to provide a tighter upper bound on the average-utilities of itemsets, and thus reduce the search space more effectively to decrease the runtime. The first pruning strategy utilizes relationships between item pairs to reduce the search space for itemsets containing three or more items. The second pruning strategy provides a tighter upper bound on the average-utilities of itemsets to prune unpromising candidates early. The third strategy reduces the time for constructing the average-utility-list structures for itemsets, which is used to calculate their upper bounds. Substantial experiments conducted on both real-life and synthetic datasets show that the proposed algorithm with three pruning strategies can efficiently and effectively reduce the search space for mining HAUIs, when compared to the state-of-the-art algorithms, in terms of runtime, number of candidates, memory usage, performance of the pruning strategies and scalability.

Efficient algorithm for mining high average-utility itemsets in incremental transaction databases

In this paper, we present a novel algorithm for efficiently mining high average-utility itemsets (HAUIs) from incremental databases, in which their volumes can be expanded dynamically. The previous algorithms have inefficiencies in that they must scan a given database multiple times so as to generate candidate itemsets and determine valid itemsets level by level. The reason is that they follow the basic framework of an Apriori-like approach. This drawback can cause critical problems in processing incremental databases because scanning a database becomes a tougher task as the size of the database is increased. In contrast, the algorithm proposed in this paper builds a compact tree structure maintaining all necessary information in order to avoid such excessive database scanning during its mining process. The previous algorithms suffer from the huge generation of unnecessary candidate itemsets at each level accompanied by the naive combination based candidate generation manner of an Apriori-like approach, which generates candidate itemsets with (k+1)-lengths by simply joining itemsets with k-lengths. On the other hand, our algorithm employs the pattern growth approach, which allows the algorithm to generate a set of only essential candidate itemsets. In order for our algorithm to constantly preserve the compactness of its tree structure during the entire incremental mining process, a restructuring technique is exploited. In the performance evaluation, we show that our algorithm is faster and consumes less memory space than competitors.

EHAUPM: Efficient High Average-Utility Pattern Mining With Tighter Upper Bounds

High-utility itemset mining (HUIM) has become a popular data mining task, as it can reveal patterns that have a high-utility, contrarily to frequent pattern mining, which focuses on discovering frequent patterns. High average-utility itemset mining (HAUIM) is a variation of HUIM that provides an alternative measure, called the average utility, to select patterns by considering both their utilities and lengths. In the last decades, several algorithms have been developed to mine high average-utility itemsets (HAUIs). But most of them consume large amounts of memory and have long execution times, since they generally utilize the average-utility upper-bound ( auub ) model to overestimate the average utilities of itemsets. To improve the performance of HAUIM, this paper proposes two novel tighter upper-bound models as alternative to the traditional auub model for miningHAUIs. The looser upper-bound model considers the remaining-maximum utility in transactions to reduce the upper bound on the utilities of itemsets. The second upper-bound model ignores irrelevant items in transactions to further tighten the upper bound. Three pruning strategies are also designed to reduce the search space for mining HAUIs by a greater amount compared with the state-of-the-art HAUI-Miner algorithm. Experiments conducted on several benchmark data sets show that the designed algorithm integrating the two novel upper-bound models outperforms the traditional HAUI-Miner algorithm in terms of runtime, memory usage, number of join operations, and scalability.

Mining of high average-utility itemsets using novel list structure and pruning strategy

A novel algorithm for efficiently mining high average-utility itemsets is presented in this paper. The algorithm utilizes list structures, which compactly capture all information needed to calculate the actual average-utilities of itemsets so as to mine all high average-utility itemsets without the generation of candidate itemsets. The algorithm thus does not require any scanning of a given transactional database after initial two scans for constructing list structures of itemsets with 1-lengths. The algorithm can generate all high average-utility itemsets through its depth-first search based mining process, which is conducted by recursively constructing list structures of itemsets with (k+1)-lengths from list structures of itemsets with k-lengths. In order to avoid the expansion of unpromising itemsets that cannot be expanded to high average-utility itemsets, a novel pruning technique using tight upper-bounds of itemsets’ average-utilities is designed and applied to the algorithm. Therefore, the runtime and memory efficiencies of the algorithm are able to be enhanced significantly because the search space of its mining process can be considerably reduced. Various experiments were performed by using four real datasets and two groups of synthetic datasets. Experimental results support that the proposed algorithm has runtime, memory, and scalability performances superior to those of existing algorithm.

An efficient algorithm to mine high average-utility itemsets

With the ever increasing number of applications of data mining, high-utility itemset mining (HUIM) has become a critical issue in recent decades. In traditional HUIM, the utility of an itemset is defined as the sum of the utilities of its items, in transactions where it appears. An important problem with this definition is that it does not take itemset length into account. Because the utility of larger itemset is generally greater than the utility of smaller itemset, traditional HUIM algorithms tend to be biased toward finding a set of large itemsets. Thus, this definition is not a fair measurement of utility. To provide a better assessment of each itemset’s utility, the task of high average-utility itemset mining (HAUIM) was proposed. It introduces the average utility measure, which considers both the length of itemsets and their utilities, and is thus more appropriate in real-world situations. Several algorithms have been designed for this task. They can be generally categorized as either level-wise or pattern-growth approaches. Both of them require, however, the amount of computation to find the actual high average-utility itemsets (HAUIs). In this paper, we present an efficient average-utility (AU)-list structure to discover the HAUIs more efficiently. A depth-first search algorithm named HAUI-Miner is proposed to explore the search space without candidate generation, and an efficient pruning strategy is developed to reduce the search space and speed up the mining process. Extensive experiments are conducted to compare the performance of HAUI-Miner with the state-of-the-art HAUIM algorithms in terms of runtime, number of determining nodes, memory usage and scalability.