Web Access Patterns Research Articles

An Optimization Method for Sequence Event Detection

Composite event processing systems are useful in various application domains such as stock data stream monitoring, RFID data management, web access pattern monitoring, etc. The tree-based method is a typical method for implementing composite event processing system. In this paper, we introduce an optimization method called “condensed composition” for the tree-based composite event processing. “Condensed composition” divides the events in groups to participate the composition. We analyze the reason why the performance is improved and propose the idea of using the statistics of the “condensation degree” to dynamically decide using condensed composition or not for different data characteristics. In the experiments, the “condensed composition” method significantly improved the performance on the real stock data.

Web content recommender system based on consumer behavior modeling

Web surfing has become a popular activity for many consumers who not only make purchases online, but also seek relevant information on products and services before they commit to buy. The authors propose a web recommender that models user habits and behaviors by constructing a knowledge base using temporal web access patterns as input. Fuzzy logic is applied to represent real-life temporal concepts and requested resources of periodic pattern-based web access activities. The fuzzy representation is used to construct a knowledge base of the user's web access habits and behaviors, which is used to provide timely personalized recommendations to the user. The proposed approach is applicable to delivery of recommendations on consumers' portable devices because compute-intensive processing is performed offline and in advance. With the increasing availability and popularity of webenabled consumer mobile devices, it is believed that the CE world of tomorrow will be increasingly web-oriented. Experiments conducted to evaluate the performance of the proposed approach have shown very good results.

맵리듀스 프레임웍 상에서 맵리듀스 함수 호출을 최적화하는 순차 패턴 마이닝 기법

시퀀스(sequence) 데이터가 주어졌을 때 그 중에서 빈번(frequent)한 순차 패턴을 찾는 순차 패턴 마이닝(sequential pattern mining)은 여러 어플리케이션(application)에 사용되는 중요한 데이터마이닝 문제이다. 순차 패턴 마이닝은 웹 접속 패턴, 고객 구매 패턴, 특정 질병의 DNA 시퀀스를 찾는 등 광범위한 분야에서 사용된다. 본 논문에서는 맵리듀스(MapReduce) 프레임웍 상에서 맵리듀스 함수 호출을 최적화하는 순차 패턴 마이닝 알고리즘을 개발하였다. 이 알고리즘은 여러 대의 기계에 데이터들을 분산시켜 병렬적으로 빈번한 순차 패턴을 찾는다. 실험적으로 다양한 데이터를 이용하여 파라미터 값을 변화시켜가며 제안된 알고리즘의 성능을 종합적으로 확인하였다. 그리고 실험 결과를 통해 제안된 알고리즘은 기계 수에 대해 선형적인 속도 개선을 보인다는 것을 확인하였다. Sequential pattern mining that determines frequent patterns appearing in a given set of sequences is an important data mining problem with broad applications. For example, sequential pattern mining can find the web access patterns, customer's purchase patterns and DNA sequences related with specific disease. In this paper, we develop the sequential pattern mining algorithms using MapReduce framework. Our algorithms distribute input data to several machines and find frequent sequential patterns in parallel. With synthetic data sets, we did a comprehensive performance study with varying various parameters. Our experimental results show that linear speed up can be achieved through our algorithms with increasing the number of used machines.

Mining Sequential Patterns in Dense Databases

Sequential pattern mining is an important data mining problem with broad applications, including the analysis of customer purchase patterns, Web access patterns, DNA analysis, and so on. We show on dense databases, a typical algorithm like Spade algorithm tends to lose its efficiency. Spade is based on the used of lists containing the localization of the occurrences of pattern in the sequences and these lists are not appropriated in the case of dense databases. In this paper we present an adaptation of the wellknown diffset data representation [12] with Spade algorithm. The new version is called dSpade. Since diffset shows high performance for mining frequent itemsets in dense transactional databases, experimental evaluation shows that dSpade is suitable for mining dense sequence databases.

EWAP-mine: enhanced mining algorithm to mine web access pattern from WAP-tree

As the information available on the World Wide Web is increasing day-by-day, access to the websites is also increasing which results in huge amount of web log data (also called web usage data). Discovery and analysis of useful information from these web logs become a practical necessity. Frequent access pattern, which is the sequence of accesses pursued by users frequently, is one of the interesting and useful knowledge in practice. Web access pattern tree (WAP-tree) mining is a frequent pattern mining technique for web log access sequences, which first stores the original web access sequence database on a prefix tree for storing non-sequential data. WAP-tree algorithm then, mines the frequent sequences from the WAP-tree by recursively reconstructing intermediate trees, starting with suffix sequences and ending with prefix sequences. In this paper, we propose a more efficient algorithm named eWAP-mine (enhanced web access pattern mining algorithm), which is based directly on the initial conditional web access sequence base (1-CWASD) of each frequent event and eliminates the need for reconstructing intermediate conditional WAP-trees.

Concurrency in Web Access Patterns Mining

Web usage mining is an interesting application of data mining which provides insight into customer behaviour on the Internet. An important technique to discover user access and navigation trails is based on sequential patterns mining. One of the key challenges for web access patterns mining is tackling the problem of mining richly structured patterns. This paper proposes a novel model called Web Access Patterns Graph (WAP-Graph) to represent all of the access patterns from web mining graphically. WAP-Graph also motivates the search for new structural relation patterns, i.e. Concurrent Access Patterns (CAP), to identify and predict more complex web page requests. Corresponding CAP mining and modelling methods are proposed and shown to be effective in the search for and representation of concurrency between access patterns on the web. From experiments conducted on large-scale synthetic sequence data as well as real web access data, it is demonstrated that CAP mining provides a powerful method for structural knowledge discovery, which can be visualised through the CAP-Graph model.

Binary Coded Web Access Pattern Tree in Education Domain

Web Access Pattern (WAP), which is the sequence of accesses pursued by users frequently, is a kind of interesting and useful knowledge in practice. Sequential Pattern mining is the process of applying data mining techniques to a sequential database for the purposes of discovering the correlation relationships that exist among an ordered list of events. WAP tree mining is a sequential pattern mining technique for web log access sequences, which first stores the original web access sequence database on a prefix tree. WAP-tree algorithm then, mines the frequent sequences from the WAP-tree by recursively re-constructing intermediate trees. In this paper, we propose efficient sequential pattern techniques called BC-WAP (Binary Coded WAP). The proposed algorithm uses Kongu Arts and Science College web logs for sequential pattern mining. It eliminates recursively reconstructing intermediate WAP trees during the mining by assigning the binary codes to each node in the WAP tree. The results of the experiments show the efficiency of the improved algorithm.

Web Access Pattern Algorithms in Education Domain

Sequential pattern mining discovers frequent user access patterns from web logs. Apriori-like sequential pattern mining techniques requires expensive multiple scans of database. So, now days, WAP (Web Access Pattern) tree based algorithm is used. It is faster than traditional techniques. However, the use of conditional search strategies in WAP-tree based mining algorithms requires re-construction of large numbers of intermediate conditional WAP-trees, which is also very costly.In this paper, Kongu Arts and Science College (KASC) web logs are taken for mining. Here, we propose an efficient sequential pattern mining techniques for KASC web log access sequences known as CS-WAP Tree. This proposed algorithm modifies the WAP tree approach for improving efficiency. The proposed algorithm totally eliminates the need to engage in numerous reconstructions of intermediate WAP trees and considerable reduces execution time. The results of experiments show the efficiency of the improved algorithm. The next key aim is to compare WAP algorithms.

Mining strong positive and negative sequential patterns

In data mining field, sequential pattern mining can be applied in divers applications such as basket analysis, web access patterns analysis, and quality control in manufactory engineering, etc. Many methods have been proposed for mining sequential patterns. However, conventional methods only consider the occurrences of itemsets in customer sequences. The sequential patterns discovered by these methods are called as positive sequential patterns, i.e., such sequential patterns only represent the occurrences of itemsets. In practice, the absence of a frequent itemset in a sequence may imply significant information. We call a sequential pattern as negative sequential pattern, which also represents the absence of itemsets in a sequence. The two major difficulties in mining sequential patterns, especially negative ones, are that there may be huge number of candidates generated, and most of them are meaningless. In this paper, we proposed a method for mining strong positive and negative sequential patterns, called PNSPM. In our method, the absences of itemsets are also considered. Besides, only sequences with high degree of interestingness will be selected as strong sequential patterns. An example was taken to illustrate the process of PNSPM. The result showed that PNSPM could prune a lot of redundant candidates, and could extract meaningful sequential patterns from a large number of frequent sequences.

Impact of memory on human dynamics

Our experience of web access slowing down is a consequence of the aggregated web access pattern of web users. This is just one example among several human-oriented services which are strongly affected by human activity patterns. Recent empirical evidence is indicating that human activity patterns are characterized by power-law distributions of inter-event times, where large fluctuations rather than regularity is the common case. I show that this temporal heterogeneity can be explained by two mechanisms: (i) humans have some perception of their past activity rate and (ii) based on that they react by accelerating or reducing their activity rate. Using these two mechanisms I explain the inter-event time statistics of Darwin's and Einstein's correspondence and the email activity within an university environment. Moreover, they are typical examples of the accelerating and reducing class, respectively. These results are relevant to the system design of human-oriented services.

Enhancing Mobile Web Access Using Intelligent Recommendations

Intelligent Web recommendations derived from frequent user Web-access patterns can help typical mobile users efficiently navigate standard Web sites. To facilitate mobile Web access, mobile clients' display resolution must gradually increase. Additionally, servers need a simple and elegant solution for displaying content effectively on mobile devices. We propose an implicit server-side approach using intelligent Web recommendations that can significantly enhance the mobile-browsing experience.

Near optimality of the discrete persistent access caching algorithm

Renewed interest in caching techniques stems from their application to improving the performance of the World Wide Web, where storing popular documents in proxy caches closer to end-users can significantly reduce the document download latency and overall network congestion. Rules used to update the collection of frequently accessed documents inside a cache are referred to as cache replacement algorithms. Due to many different factors that influence the Web performance, the most desirable attributes of a cache replacement scheme are low complexity and high adaptability to variability in Web access patterns. These properties are primarily the reason why most of the practical Web caching algorithms are based on the easily implemented Least-Recently-Used (LRU) cache replacement heuristic. In our recent paperJelenković and Radovanović (2004c), we introduce a new algorithm, termed Persistent Access Caching (PAC), that, in addition to desirable low complexity and adaptability, somewhat surprisingly achieves nearly optimal performance for the independent reference model and generalized Zipf's law request probabilities. Two drawbacks of the PAC algorithm are its dependence on the request arrival times and variable storage requirements. In this paper, we resolve these problems by introducing a discrete version of the PAC policy (DPAC) that, after a cache miss, places the requested document in the cache only if it is requested at least $k$ times among the last $m$, $m \geq k$, requests. However, from a mathematical perspective, due to the inherent coupling of the replacement decisions for different documents, the DPAC algorithm is considerably harder to analyze than the original PAC policy. In this regard, we develop a new analytical technique for estimating the performance of the DPAC rule. Using our analysis, we show that this algorithm is close to optimal even for small values of $k$ and $m$, and, therefore, adds negligible additional storage and processing complexity in comparison to the ordinary LRU policy.

Mining Web Log Sequential Patterns with Position Coded Pre-Order Linked WAP-Tree

Sequential mining is the process of applying data mining techniques to a sequential database for the purposes of discovering the correlation relationships that exist among an ordered list of events. An important application of sequential mining techniques is web usage mining, for mining web log accesses, where the sequences of web page accesses made by different web users over a period of time, through a server, are recorded. Web access pattern tree (WAP-tree) mining is a sequential pattern mining technique for web log access sequences, which first stores the original web access sequence database on a prefix tree, similar to the frequent pattern tree (FP-tree) for storing non-sequential data. WAP-tree algorithm then, mines the frequent sequences from the WAP-tree by recursively re-constructing intermediate trees, starting with suffix sequences and ending with prefix sequences. This paper proposes a more efficient approach for using the WAP-tree to mine frequent sequences, which totally eliminates the need to engage in numerous re-construction of intermediate WAP-trees during mining. The proposed algorithm builds the frequent header node links of the original WAP-tree in a pre-order fashion and uses the position code of each node to identify the ancestor/descendant relationships between nodes of the tree. It then, finds each frequent sequential pattern, through progressive prefix sequence search, starting with its first prefix subsequence event. Experiments show huge performance gain over the WAP-tree technique.

Adaptive neural network clustering of Web users

The degree of personalization that a Web site offers in presenting its services to users is an important attribute contributing to the site's popularity. Web server access logs contain substantial data about user access patterns. One way to solve this problem is to group users on the basis of their Web interests and then organize the site's structure according to the needs of different groups. Two main difficulties inhibit this approach: the essentially infinite diversity of user interests and the change in these interests with time. We have developed a clustering algorithm that groups users according to their Web access patterns. The algorithm is based on the ART1 version of adaptive resonance theory. In our ART1-based algorithm, a prototype vector represents each user cluster by generalizing the URLs most frequently accessed by all cluster members. We have compared our algorithm's performance with the traditional k-means clustering algorithm. Results showed that the ART1-based technique performed better in terms of intracluster distances. We also applied the technique in a prefetching scheme that predicts future user requests.

An efficient forward-backward algorithm for an explicit-duration hidden Markov model

Existing algorithms for estimating the model parameters of an explicit-duration hidden Markov model (HMM) usually require computations as large as O((MD/sup 2/ + M/sup 2/)T) or O(M/sup 2/ DT), where M is the number of states; D is the maximum possible interval between state transitions; and T is the period of observations used to estimate the model parameters. Because of such computational requirements, these algorithms are not practical when we wish to construct an HMM model with large state space and large explicit state duration and process a large amount of measurement data to obtain high accuracy. We propose a new forward-backward algorithm whose computational complexity is only O((MD + M/sup 2/)T), a reduction by almost a factor of D when D > M and whose memory requirement is O(MT). As an application example, we discuss an HMM characterization of access traffic observed at a large-scale Web site: we formulate the Web access pattern in terms of an HMM with explicit duration and estimate the model parameters using our algorithm.

NCSA's World Wide Web server: design and performance

To support continued growth, WWW servers must manage a multigigabyte (in some instances a multiterabyte) database of multimedia information while concurrently serving multiple request streams. This places demands on the servers' underlying operating systems and file systems that lie far outside today's normal operating regime. Simply put, WWW servers must become more adaptive and intelligent. The first step on this path is understanding extant access patterns and responses. The article examines extant Web access patterns with the aim of developing more efficient file-caching and prefetching strategies.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>