The Object-Oriented paradigm approaches the software development by representing real world entities into classes of software objects. Interactions between classes can be captured by patterns. A pattern language is a collection of patterns composed to solve a complex design problem. This paper presents a collection of object-oriented design patterns structured to form a pattern language for Rol...

We propose a practice-oriented scheme for protecting RAM access pattern. We first consider an instance which relies on the use of a secure (trusted) hardware buffer; it achieves both security and performance levels acceptable in practice by adapting ideas from oblivious RAM mechanisms, yet without the expensive (re-)shuffling of buffers. Another instance requires no special hardware, but as a r...

The data grid technology, which uses the scale of the Internet to solve storage limitation for the huge amount of data, has become one of the hot research topics. Recently, data replication strategies have been widely employed in distributed environment to copy frequently accessed data in suitable sites. The primary purposes are shortening distance of file transmission and achieving files from ...

With the explosive growth of data available on the World Wide Web, discovery and analysis of useful information from the World Wide Web becomes a practical necessity. Web access pattern, which is the sequence of accesses pursued by users frequently, is a kind of interesting and useful knowledge in practice. In this paper, we study the problem of mining access patterns from Web logs e ciently. A...

We present a case study in which sequence mining algorithms were applied to web access log data. The data are from a portal that is targeted for business users. In this portal, like in many others, content is described using a set of descriptors, such as keywords, category and type. We investigate whether representing content by the type rather than its identifier enables existing sequence mini...

In this paper, we develop a new indexing method for large web access-logs. We are concerned with pattern queries, which advocate the search for access sequences that contain certain query patterns. They find applications in processing web-log mining results (e.g., finding typical/atypical access-sequences). The proposed method focuses on scalability to web-logs’ sizes. For this reason, we exami...

Privacy and confidentiality are crucial issues in content-based publish/subscribe (CBPS) networks. We tackle the problem of end-user privacy in CBPS. This problem raises a challenging requirement for handling encrypted data for the purpose of routing based on protected content and encrypted subscription information. We suggest a solution based on a commutative multiple encryption scheme in orde...

Access control is concerned with granting access to sensitive data based on conditions that relate to the past or present, so-called provisions. Expressing requirements from the domain of data protection necessitates extending this notion with conditions that relate to the future. Obligations, in this sense, are concerned with commitments of the involved parties. At the moment of granting acces...

A recurring security scenario involves the problem of removing the access rights of an employee upon employee termination. A solution is presented in the form of procedures and an infrastructure. Operationally, sensors track security-related user operations (e.g. password use and object accesses) to determine the true access rights associated with a user. Security administrators combine that in...

In this paper we present our A/V collaboration system based on our XGSP collaboration framework and NaradaBrokering messaging middleware. Using publish/subscribe event model, this system can provide videoconferencing services to heterogeneous endpoints such as H.323, SIP and Access Grid. This paper discusses the common a/v collaboration model shared by all kinds of A/V conferencing clients and ...