Popularity of mobile devices is accompanied by widespread security problems, such as MAC address spoofing in wireless networks. We propose a probabilistic approach to temporal anomaly detection using smoothing technique for sparse data. Our technique builds up on the Markov chain, and clustering is presented for reduced storage requirements. Wireless networks suffer from oscillations between lo...

In order to protect vital data in today’s internet environment and prevent misuse, especially insider abuse by valid users, we propose a novel two-step detecting approach to distinguish potential misuse behaviour (namely anomalous user behaviour) from normal behaviour. First, we capture the access patterns of users by using association rules. Then, based on the patterns and users’ sequential be...

There has been significant recent interest in studying consumer behavior in sponsored search environments. Sponsored search is the fastest growing form of advertising on the Internet. A number of factors have contributed to this growth. The ads tend to be highly targeted and offer a higher return on investment for advertisers compared to other marketing methods. In addition the large audience i...

Social media systems rely on user feedback and rating mechanisms for personalization, ranking, and content filtering. However, when users evaluate content contributed by fellow users (e.g., by liking a post or voting on a comment), these evaluations create complex social feedback effects. This paper investigates how ratings on a piece of content affect its author’s future behavior. By studying ...

Traffic generation in mobile networks is heavily dependent on user behavior because the users move around with their terminals. For example, at a special event such as a fireworks display or football game, the people will congregate in a specific place and may try to make calls, generating unpredictable excessive traffic, leading to network congestion. When the users cannot get through due to c...

Existing desktop search applications, trying to keep up with the rapidly increasing storage capacities of our hard disks, are an important step towards more efficient personal information management, yet they offer an incomplete solution. While their indexing functionalities in terms of different file types they are able to cope with are impressive, their ranking capabilities are basic, and rel...

* This work was performed in the BISANTE (Broadband Integrated Satellite Network Traffic Evaluations) Esprit project supported by the EC under research grant EP28425. See http://www.bisante.org ABSTRACT In this paper, a user-behavior oriented workload generator for OPNET is presented. In this novel approach, both packet generation and user interaction with applications and services that cause t...

As ubiquitous computing (ubicomp) technologies reach maturity, smart phones and context-based services are gaining mainstream popularity. A smart phone accompanies its user throughout (nearly) all aspects of his life, becoming an indispensable assistant the busy user relies on to help navigate his life, using map applications to navigate the physical world, email and instant messaging applicati...