The need to securely share information on an ad-hoc basis between collaborating entities is increasingly becoming important. We propose a coalition based access control model (CBAC), comprised of three layers: coalition, role and user-object. Our model enables translation of coalition level policies to implementation level access control in a manner similar to that of the layers of the TCP/IP p...

In the area of agent-based computing there are many proposals for speciic system architectures, and a number of proposals for general approaches to building agents. As yet, however, there are few attempts to relate these together, and even fewer attempts to provide methodologies which relate designs to architectures and then to exe-cutable agents. This paper provides a rst attempt to address th...

* We present visualization and layout algorithms that can enhance informal storytelling using personal digital data such as photos in a face-to-face social setting. In order to build a more intuitive browser for retrieval, navigation and story-telling, we introduce a novel optimized layout technique for large image sets, which respects (context-sensitive) mutual similarities as visualized on a ...

We explore the idea of using a possibilistic graphical model as the basis for a world model that drives a dialog system. As a first step we have developed a system that uses text-based dialog to derive a model of the user’s family relations. The system leverages its world model to infer relational triples, to learn to recover from upstream coreference resolution errors and ambiguities, and to l...

The popularization of mobile devices in the last years has led to the development of an increasing number of services. However the technical limitations of mobile devices call for services that require minimal interactions with the user and adapt their behaviors to the user’s expectations. Context-awareness has proven to facilitate personalization of services by enabling the adaptation of the s...

In this paper we present a novel approach to shape similarity estimation based on ordinal correlation. The proposed method operates in three steps: object alignment, contour to multilevel image transformation and similarity evaluation. This approach is suitable for use in CBIR. The proposed technique produced encouraging results when applied on the MPEG-7 test data.

With the advent of mobile computing and mobile services becoming more widespread and more complex, the development process of those services requires an ever more important focus on numerous design issues. The heterogeneous environment, reaching from different networks and devices to different software platforms embedded on such devices, implies difficulties in making a mobile service broadly a...

Exploratory learning has been proved to be beneficial for learning when guidance and support is provided. This is a challenging issue as balance between freedom and control is a strong requirement in this context. In this paper the challenges involved are discussed together with the way they affect the process of learner modelling. We discuss previous attempts to model the learner in explorator...

Personalisation and context-awareness are fundamental concerns in Telephony. This paper introduces a rule-based system 4CRULES which enables context-sensitive call control by the means of feature configuration rules. 4CRULES is interoperable with standard context services and compositional feature architectures. It has been designed to resolve feature interactions, manage conflicting preference...