Towards Effects-Based Service Description And Integration In Pervasive Environments Aitor Urbieta, Ekain Azketa, Inma Gomez, Jorge Parra Software Technologies Area Ikerlan Technological Research Centre 20500 Mondragon, Spain aurbieta@ikerlan.es Nestor Arana Computing and Electronics Department Mondragon Unibertsitatea 20500 Mondragon, Spain narana@eps.mondragon.edu ABSTRACT In the vision of pervasive computing environments, these are populated by smart devices which adapt depending on the user context in order to meet the user needs and look after them. Nevertheless, current devices describe their functio- nalities in a very simple manner (not in an expressive way) and therefore, it is difficult to automate the behaviour of the environment, service discovery and aggregation. Some current research works are trying to tackle these problems. In a previous work we justified the need for an effects- and conditions-based approach for service representation in this kind of environments. An analysis of the main semantic ser- vice description languages was also carried out, concluding that none of them provides an ontological model for effects and conditions definition. The main aim of this research work is to cover this gap defining and describing an onto- logy for semantic representation of effects and conditions for user interaction, service discovery and service integration in pervasive environments. Categories and Subject Descriptors D.2.11 [Software Engineering]: Software Architectures General Terms Design, Experimentation Keywords Effects, conditions, context, semantic services, pervasive ser- vices 1. INTRODUCTION A pervasive environment establishes a mechanism to pro- vide users with all the functionality of the devices, com- ponents and local and distributed software applications in a flexible, integrated and almost transparent way for the Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. SIPE’08, July 7, 2008, Sorrento, Italy. Copyright 2008 ACM 978-1-60558-208-5/08/07 ...$5.00. end-user as Weiser states in [28]. All this implies that the computational devices are integrated, embedded and distri- buted in the physical media and surroundings around us. It is, therefore, a non-intrusive distribution of all these devices with the goal of offering user-centred functions. These environments, instead of being seen as a set of no- des and independent computational components, must be observed as the medium that allows users to complete a set of simple or complex tasks by using the available services. In order to do that, the devices must be aware of the exis- tence of other devices and must be able to establish coali- tions among them with limited human intervention if any at all [11]. Pervasive computing tries to get away from the paradigm of the user in front of a PC as the only interaction mechanism with software components and tries to promote the use of mobile and embedded devices [3]. All this will lead us to change many of the current application design patterns to adapt to the new challenges opened up by this ever increasing type of device such as dynamicity, mobility, resource constraints, connectivity, etc. Nowadays, we are already surrounded by many devices. We are referring not only to PCs, PDAs or mobile phones as computational nodes, but also a wide variety of devi- ces such as embedded devices [8], cars, TVs, DVD players, multimedia portable devices, video game players, domestic appliances, etc. Although we have the necessary infrastruc- ture to achieve the goal proposed by Weiser [28], the reality is that we are a long way from doing so. The main fact that explains this paradox is that the majority of the de- vices are isolated and furthermore the features they offer are described in a syntactic or semantic way, but exclusively based on inputs and outputs, so the functionalities offered by services cannot be adequately consumed by users or ot- her devices that populate the environment. That is why it is necessary to have mechanisms that describe services with more information related to the service behaviour and a way to achieve this is by using effects (produced in the world after the correct execution of the service) and con- ditions (necessary for the correct execution of the service). In this way, an adequate service selection could be achieved for not only a low-level service representation (operations described by inputs and outputs) but also high level service behaviour (described with necessary effects and conditions in the environment). Thus, this paper tries to bridge the gap between services behaviour and contextual information using an ontological model for service effects and condition representation. 1