Handling Data-Based Concurrency in Context-Aware Service Protocols

Dependency analysis is a technique to identify and determine data dependencies between service protocols. Protocols evolving concurrently in the service composition need to impose an order in their execution if there exist data dependencies. In this work, we describe a model to formalise context-aware service protocols. We also present a composition language to handle dynamically the concurrent execution of protocols. This language addresses data dependency issues among several protocols concurrently executed on the same user device, using mechanisms based on data semantic matching. Our approach aims at assisting the user in establishing priorities between these dependencies, avoiding the occurrence of deadlock situations. Nevertheless, this process is error-prone, since it requires human intervention. Therefore, we also propose verification techniques to automatically detect possible inconsistencies specified by the user while building the data dependency set. Our approach is supported by a prototype tool we have implemented.Comment: In Proceedings FOCLASA 2010, arXiv:1007.499

Ontology-Based Context-Aware Service Discovery for Pervasive Environments

Existing service discovery protocols use a service matching process in order to offer services of interest to the clients. Potentially, the context information of the services and client can be used to improve the quality of service matching. To make use of context information in service matching, service discovery needs to address certain challenges. Firstly, it is required that the context information should have unambiguous representation. Secondly, the mobile devices should be able to disseminate context information seamlessly in the fixed network. And thirdly, dynamic nature of the context information should be taken into account. The proposed Context Aware Service Discovery (CASD) architecture deals with these challenges by means of an ontological representation and processing of context information, a concept of nomadic mobile context source and a mechanism of persistent service discovery respectively. This paper discusses proposed CASD architecture, its implementation and suggests further enhancements

Goal-Driven Context-aware Service Composition

Two important aspects are associated with service composition. One is to understand the needs and constraints for a new added-value composite service, and otherwise it would lead to an ad-hoc effort for service composition. The second is to reflect the changes of computing environment to the service composition to catch up the on-demand of users. This paper introduces a goal-driven approach to specify the user requirements and demands that guides the service composition, and proposes context awareness to adapt to a dynamically changing environment. Computing contexts, including physical context, user profile and computed results, are gathered by various services, and imported into an ontology based a context repository. A Goal Description Language, Context Condition/Effect are designed to describe the dynamic semantics of goal requirements and service capability. A planner is designed and implemented to dynamically compose services based on the current contexts, and a service runner is designed and implemented to invoke proper services based on the contexts and interactions with users. ?2010 IEEE.EI

A Distributed Context-Aware Trust Management Architecture

The realization of a pervasive context-aware service platform imposes new challenges for the security and privacy aspects of the system in relation to traditional service platforms. One important aspect is related with the management of trust relationships, which is especially hard in a pervasive environment because users are supposed to interact with entities unknown before hand in an ad-hoc and dynamic manner. Current trust management solutions do not adapt nor scale well in this dynamic service provisioning scenario because they require previously defined trust relationships in order to operate. The objective of this thesis is to design, prototype and validate a context-aware distributed trust management architecture in order to address: (a) the lack of integration between available trust solutions and security and privacy management languages, and (b) the dynamic characteristics of a context-aware service platform

Context-Aware Service Discovering System for Nomad Users

International audienceThis paper presents an architecture for a system that provides nomad users, context-aware personalised services. Users might need any sort of services: information about the weather forecast for the next day, or about a museum in the neighbour worth to visit. These services are known as stateless services. More complex situations ocurre when services are stateful. Such services are, for example those which need users to be logged in (e.g. booking a room in a hotel). The question discussed in the text are those related to: i) user's privacy, ii) recommendation and discovery of services, iii) composition of recommended services into a composite service, and iv) execution of the resulting composite service

Context-Aware Service Selection with Uncertain Context Information

The current evolution of Service-Oriented Computing in ubiquitous systems is leading to the development of context-aware services. These are services whose description is enriched with context information related to the service execution environment and adaptation capabilities. This information is often used for discovery and adaptation purposes. However, in real-life systems context information is naturally dynamic, uncertain and incomplete, which represents an important issue when comparing service description and user requirements. Uncertainty of context information may lead to an inexact match between provided and required service capabilities, and consequently to the non-selection of services. In order to handle uncertain and incomplete context information, we propose a mechanism inspired by graph-comparison for matching contextual service descriptions using similarity measures that allow inexact matching. Service description and requirements are compared using two kinds of similarity measures: local measures, which compare individually required and provided properties, and global measures, which take into account the context description as a whole. We show how the proposed mechanism is integrated in MUSIC, an existing adaptation middleware, and how it enables more optimal adaptation decision making

Rule-based Reasoning Mechanism for Context-aware Service Presentation

With universal usability geared towards user focused customisation, a context reasoning engine can derive meaning from the various context elements and facilitate decision-taking for applications and context delivery mechanisms. The heterogeneity of available device capabilities means that the recommendation algorithm must be in a formal, effective and extensible form. Moreover, user preferences, capability context and media metadata must be considered simultaneously to determine appropriate presentation format. Towards this aim, this paper presents a reasoning mechanism that supports service presentation through a rule-based mechanism. The validation of the approach is presented through application use cases

Business Model Development for a Mobile Context-aware Service

Mobile information services, preceded on tablet computers, smartphones or other mobile devices, are a significant source of information for people nowadays. By including context data, a new category of information services has been established. On the application side, a range of innovative services, providing the user with an added-value, could be observed in the previous years, boosted by the wide-spread adoption of smartphones in developed countries. For the application provider, the question how to configure the business model is crucial: several factors such as the service configuration, the revenue model and the configuration of the value creation network, which all can be seen as decisive factors for success or failure of a service. In this paper we present a context-aware service named \u27Digital Graffiti\u27 and describe the process of the business model development. As an outcome of this process, a specific business model, based on feasibility and future prospect, was chosen and further described

Context-aware service front-ends

Context-aware adaptation of user interfaces have been investigated since the early 80's to provide mechanisms for stakeholders to propose, implement and execute adaptation, enabling users to efficiently interact with adaptive and adaptable applications. Today, adapting UIs according to the context of use becomes inevitable. Not only because users interact with applications from many distinct environments (platforms, devices and users' profile vary significantly), but also because such applications must provide a high usability level regardless of the contexts of use, efficiently adapting themselves according to the context. In this sense, Serenoa project proposes its 2nd workshop, to join experts in the domain of context-aware adaptation to exchange experiences, discuss current trends, promote approaches, and raise awareness for this field