A case study on the transformation of context-aware domain data onto XML schemas

In order to accelerate the development of context-aware applications, it would be convenient to have a smooth path between the context models and the automated services that support these models. This paper discusses how MDA technology (metamodelling and the QVT standard) can support the transformation of high-level models of context-aware services onto the implementation of these services using web services. The total transformation process from context-aware services onto web services involves the following aspects: 1. service signatures, which should be translated onto WSDL definitions; 2. context-aware domain data used as input and output data in service operations, which should be translated onto XML schemas; and 3. service behaviours, which should be used to generate the service implementation. This paper concentrates on the modelling and transformation of the context-aware domain data. The results of this paper are generally applicable to the transformation of elements of any domain-specific language expressed in terms of a metamodel onto XML Schema data

Context-aware adaptation in DySCAS

DySCAS is a dynamically self-configuring middleware for automotive control systems. The addition of autonomic, context-aware dynamic configuration to automotive control systems brings a potential for a wide range of benefits in terms of robustness, flexibility, upgrading etc. However, the automotive systems represent a particularly challenging domain for the deployment of autonomics concepts, having a combination of real-time performance constraints, severe resource limitations, safety-critical aspects and cost pressures. For these reasons current systems are statically configured. This paper describes the dynamic run-time configuration aspects of DySCAS and focuses on the extent to which context-aware adaptation has been achieved in DySCAS, and the ways in which the various design and implementation challenges are met

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

System Support for Managing Invalid Bindings

Context-aware adaptation is a central aspect of pervasive computing applications, enabling them to adapt and perform tasks based on contextual information. One of the aspects of context-aware adaptation is reconfiguration in which bindings are created between application component and remote services in order to realize new behaviour in response to contextual information. Various research efforts provide reconfiguration support and allow the development of adaptive context-aware applications from high-level specifications, but don't consider failure conditions that might arise during execution of such applications, making bindings between application and remote services invalid. To this end, we propose and implement our design approach to reconfiguration to manage invalid bindings. The development and modification of adaptive context-aware applications is a complex task, and an issue of an invalidity of bindings further complicates development efforts. To reduce the development efforts, our approach provides an application-transparent solution where the issue of the invalidity of bindings is handled by our system, Policy-Based Contextual Reconfiguration and Adaptation (PCRA), not by an application developer. In this paper, we present and describe our approach to managing invalid bindings and compare it with other approaches to this problem. We also provide performance evaluation of our approach

An Event-Based Coordination Model for Context-Aware Applications

International audienceContext-aware applications adapt their behavior depending on changes in their environment context. Programming such applications in a modular way requires to modularize the global context into more specific contexts and attach specific behavior to these contexts. This is reminiscent of aspects and has led to the notion of context-aware aspects. This paper revisits this notion of context-aware aspects in the light of previous work on concurrent event-based aspect-oriented programming (CEAOP). It shows how CEAOP can be extended in a seamless way in order to define a model for the coordination of concurrent adaptation rules with explicit contexts. This makes it possible to reason about the compositions of such rules. The model is concretized into a prototypical modeling language

Towards a user-centric and multidisciplinary framework for designing context-aware applications

Research into context-aware computing has not sufficiently addressed human and social aspects of design. Existing design frameworks are predominantly software orientated, make little use of cross-disciplinary work, and do not provide an easily transferable structure for cross-application of design principles. To address these problems, this paper proposes a multidisciplinary and user-centred design framework, and two models of context, which derive from conceptualisations within Psychology, Linguistics, and Computer Science. In a study, our framework was found to significantly improve the performance of postgraduate students at identifying the context of the user and application, and the usability issues that arise

Modeling Adaptive Behaviors in Context UNITY

Context-aware computing refers to a paradigm in which applications sense aspects of the environment and use this information to adjust their behavior in response to changing circumstances. In this paper, we present a formal model and notation (Context UNITY) for expressing quintessential aspects of context-aware computations; existential quantification, for instance, proves to be highly effective in capturing the notion of discovery in open systems. Furthermore, Context UNITY treats context in a manner that is relative to the specific needs of an individual application and promotes an approach to context maintenance that is transparent to the ap-plication. In this paper, we construct the model from first principles, introduce its proof logic, and demonstrate how the model can be used as an effective abstraction tool for context-aware applications and middleware

Toward a multidisciplinary model of context to support context-aware computing

Capturing, defining, and modeling the essence of context are challenging, compelling, and prominent issues for interdisciplinary research and discussion. The roots of its emergence lie in the inconsistencies and ambivalent definitions across and within different research specializations (e.g., philosophy, psychology, pragmatics, linguistics, computer science, and artificial intelligence). Within the area of computer science, the advent of mobile context-aware computing has stimulated broad and contrasting interpretations due to the shift from traditional static desktop computing to heterogeneous mobile environments. This transition poses many challenging, complex, and largely unanswered research issues relating to contextual interactions and usability. To address those issues, many researchers strongly encourage a multidisciplinary approach. The primary aim of this article is to review and unify theories of context within linguistics, computer science, and psychology. Summary models within each discipline are used to propose an outline and detailed multidisciplinary model of context involving (a) the differentiation of focal and contextual aspects of the user and application's world, (b) the separation of meaningful and incidental dimensions, and (c) important user and application processes. The models provide an important foundation in which complex mobile scenarios can be conceptualized and key human and social issues can be identified. The models were then applied to different applications of context-aware computing involving user communities and mobile tourist guides. The authors' future work involves developing a user-centered multidisciplinary design framework (based on their proposed models). This will be used to design a large-scale user study investigating the usability issues of a context-aware mobile computing navigation aid for visually impaired people

Weaving a fabric of socially aware agents

The expansion of web-enabled social interaction has shed light on social aspects of intelligence that have not been typically studied within the AI paradigm so far. In this context, our aim is to understand what constitutes intelligent social behaviour and to build computational systems that support it. We argue that social intelligence involves socially aware, autonomous individuals that agree on how to accomplish a common endeavour, and then enact such agreements. In particular, we provide a framework with the essential elements for such agreements to be achieved and executed by individuals that meet in an open environment. Such framework sets the foundations to build a computational infrastructure that enables socially aware autonomy.This work has been supported by the projects EVE(TIN2009-14702-C02-01) and AT (CSD2007-0022)Peer Reviewe