Maria Strimpakou

Hybrid context modeling: a location-based scheme using ontologies

Context awareness is an inherent feature of pervasive computing. It enhances the proactiveness of the system thus requiring less user attention and fewer human-machine interactions, it supports intelligent personalization features, and it can assist the system to address the user requirements considering the current conditions. Nevertheless, in such environments, various types of context information are involved and need to be efficiently managed and maintained, soundly interpreted, rapidly processed, and securely disseminated by the system. Thus, an interoperable and flexible context representation scheme is necessary that will support efficient context interpretation and reasoning and will perform well in distributed large-scale context-aware systems. This paper is concerned with the development of a hybrid context representation scheme that aims to combine the maintenance, distribution and administrative facilities of a location-based context model and the semantic advantages of context ontologies

Context modelling and management in ambient-aware pervasive environments

Services in pervasive computing systems must evolve so that they become minimally intrusive and exhibit inherent proactiveness and dynamic adaptability to the current conditions, user preferences and environment. Con-text awareness has the potential to greatly reduce the human attention and interaction bottlenecks, to give the user the impression that services fade into the background, and to support intelligent personalization and adaptability features. To establish this functionality, an infrastructure is required to collect, manage, maintain, synchronize, infer and disseminate context information towards applications and users. This paper presents a context model and ambient context management system that have been integrated into a pervasive service platform. This research is being carried out in the DAIDALOS IST Integrated Project for pervasive environments. The final goal is to integrate the platform developed with a heterogeneous all-IP network, in order to provide intelligent pervasive services to mobile and non-mobile users based on a robust context-aware environment.

Location-based context retrieval and filtering

Context-based applications are supposed to decrease human-machine interactions. To this end, they must interpret the meaning of context data. Ontologies are a commonly accepted approach of specifying data semantics and are thus considered a precondition for the implementation of context-based systems. Yet, experiences gained from the European project Daidalos evoke concerns that this approach has its flaws when the application domain can hardly be delimited. These concerns are raised by the human limitation in dealing with complex specifications. This paper proposes a relaxation of the situation: Humans strength is the understating of natural languages, computers, however, possess superior pattern matching power. Therefore, it is suggested to enrich or even replace semantic specifications of context data items by free-text descriptions. For instance, rather than using an Ontology specification to describe an Italian restaurant the restaurant can simply be described by its menu card. To facilitate this methodology, context documents are introduced and a novel information retrieval approach is elucidated, evaluated, and analysed with the help of Bose-Einstein statistics. It is demonstrated that the new approach clearly outperforms conventional information retrieval engines and is an excellent addition to context Ontologies.

COMPACT: Middleware for context representation and management in pervasive computing

Context awareness is one of the key aspects of pervasive computing systems. In such systems, a plethora of dynamic context information needs to be constantly retrieved, soundly interpreted, rapidly processed, maintained in various repositories, and securely disseminated. Thus, a flexible, scalable and interoperable context representation scheme needs to be established and solid context management mechanisms need to be adopted, which will perform well in large‐scale distributed pervasive systems. This paper elaborates on the COMPACT context middleware that has been designed to cope with the issues above and saturate pervasive computing environments with context awareness functionality.

Privacy-Aware Modelling and Distribution of Context Information in Pervasive Service Provision

Context awareness is an essential cornerstone in future pervasive computing systems. It has the potential to greatly reduce the user attention and interaction bottlenecks, to give humans the impression that services fade into the background, and to support intelligent personalization features. Nevertheless, in order to create such an environment, a growing amount of personal information has to be provided to the system, either manually or automatically. Hence the digital trace and representation users have in the system is getting dangerously detailed, thus stressing the need for privacy protection. DAIDALOS (Satyanarayanan, 2001) is a European research project in the area of 3G and beyond, which aims to combine heterogeneous networks in a transparent and seamless way, and develop on top of this a pervasive environment for applications and end-users. This paper describes the main models and mechanisms that have been established to provide federated context-aware services and protect the privacy of their users

Optimising context data dissemination and storage in distributed pervasive computing systems

Context management systems are expected to administrate large volumes of spatial and non-spatial information in geographical disperse domains. In particular, when these systems cover wide areas such as cities, countries or even the entire planet, the design of scalable storage, retrieval and propagation mechanisms is paramount. This paper elaborates on mechanisms that address advanced requirements, including support for distributed context databases management; efficient query handling; innovative management of mobile physical objects and optimization strategies for distributed context data dissemination. These mechanisms establish a robust spatially-enhanced distributed context management framework that has already been designed and carefully implemented and thoroughly evaluated.

Designing next generation middleware for context-aware ubiquitous and pervasive computing

Ubiquitous computing systems that strive to be minimally intrusive and exhibit inherent pro-activeness and dynamic adaptability to the user preferences and environment need to be context-aware. Context Awareness (CA) has the potential to greatly alleviate the human attention and interaction bottlenecks, increase the service flexibility and support intelligent personalisation and adaptability features. This paper has sprung out from the work in Daidalos IST Integrated Project on the development of a ubiquitous and pervasive service provisioning platform. This platform is based on a robust context-aware environment that aims to advance the vision of Ambient Intelligence (AmI) toward technical and economic viability.

Distributed Spatial Database Management for Context Aware Computing Systems

Context management systems collect large volumes of spatial and non-spatial information. In particular, when these systems cover large areas like cities, countries or even the entire planet, the design of scalable storage, retrieval and delivery mechanisms is paramount. The Daidalos context management system has been design to meet the requirements of large scale systems. This paper presents the Daidalos approach for a scalable distributed data management approach. The system architecture, the management of mobile database nodes and federation issues are described.

Experiences with middleware and mobile agents in an e-commerce European project

This paper presents several experiences and conclusions about the usage of the J2EE middleware platform in an e-commerce mediation framework, and introduces mobile agent possibilities within the same environment. The main conclusions are taken from the Smart-EC project, where J2EE and mobility are considered as a value added in its architecture. Other advanced technologies such as XML based multi-device publishing and the utilisation of e-commerce ontologies to handle static and dynamic aspects of complex services or to control their transactional properties, are also considered in the project.

Seamless Incorporation of Agents in an E-Commerce Intermediation Platform

This paper describes the realization of a business-to-business intermediation e-commerce platform. The main concern derives from the combined usage of two emerging technologies, namely the Java 2 Enterprise Edition (J2EE) and the Mobile Agent Technology (MAT). The key issues that are addressed in this paper are the following. First, the scenario of the proposed system. Second, the definition of the required functionality and its design by means of appropriate service components based on J2EE principles. Third, the exploitation of agents in terms of their detailed design and implementation activities. Finally, the evaluation of the two interoperable technologies.