Unanticipated Dynamic Adaptation of Context-Aware Services

2013 IEEE 20th International Conference on Web Services, 2013

The idea to build systems based on services, by reusing and combining software made available independently via different technologies and channels and dynamically organizing them into coherent processes, has a very well recognized potential. Achieving this potential stands crucially on the ability to recognize and exploit the context in which such applications operate, in terms of the available services, of the actual setup at run-time, and of the interaction with human actors. Changing contexts require run-time reaction, by adapting the ongoing overall process enacted by the service-based system to unexpected deviations. Continuous context-aware adaptation is hencefore a strong requirement in this setting. In this paper, we propose a service delivery platform designed for the continuous context-aware adaptation of service-based systems, based on the idea of monitoring the underlying context via a hierarchical model, and using the context to drive the choice and execution of adaptive pervasive flows. We describe the approach through an example from the smart cities e-mobility domain.

2013 IEEE International Conference on Services Computing, 2013

There is an increasing demand for context-aware adaptive services that can evolve at runtime in response to unanticipated changes in their environments or functionalities. Enabling the runtime evolution of such context-aware adaptive services is still a major challenge. In this paper, we introduce a novel approach to tackle this challenge. At the development time, our approach explicitly models a context-aware adaptive service from three aspects: functionality, context, and adaptive behaviour. As such, these aspects and their relationships can be clearly captured and easily manipulated. The approach also generates the executable artifacts of the composite service from their models. These artifacts are engineered with the ability to be changed at runtime (i.e. evolvable artifacts). To cope with unanticipated changes, we adopt the models@runtime concept for keeping the service model alive at runtime. This model is then manipulated by the software engineer to take into account such changes. To apply the model changes to the running service's composition, differences between the running service model and its evolved model are computed. Then, adaptation actions corresponding to the differences are generated and applied to the service's evolvable artifacts. To demonstrate the approach applicability, we have used it to develop and evolve two case studies: travel guide and electronic exam services.

2013 ACS International Conference on Computer Systems and Applications (AICCSA), 2013

Ubiquitous computing has revolutionized the way we use computing. The widespread of wearable devices and the seamless connectivity between them have transcended the traditional computing era to the pervasive computing and enable new opportunities for a user to perform his/her operation all the time and everywhere. These new environments are characterized by large quantity of heterogeneous services and context-aware applications that dynamically join and leave the network. Such environment will constitute a large-scale internetworking infrastructure and likely to provide a new level of openness and dynamics. For achieving its goal, ubiquitous computing needs the context data brought by the seamlessly connected devices either mobile handset or embedded in the surrounding physical environment and imperceptible to a user. Indeed, context and context-awareness provide computing spaces with the capability to usefully adapt the services they provide. We present our mechanism of adaptation of services by a policy-driven, contextaware manner. The adaptation is based on enumerating the different policies of a service object. As the execution environment, user context and preferences change, the service object will be adapted to use different behaviors, driven by user preferences. The adaptation process is able to capture and to process context-dependent preferences and qualitative uncertainty labels which are used to determine which set of preferences should be considered in a given context. To demonstrate this mechanism we will provide an example scenario and evaluate our solution.

2007 IEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications, 2007

Technology is paving the way for ubiquitous services. However, the delivery environment is characterized by its complexity which emanates from the diversity in end user terminals and networking infrastructures. Hence, adaptation is vital to the portability and personalization of the ever increasing content and services offered to users. This paper proposes a context-aware Adaptation Manager architecture for adaptation management. The architecture aims to analyse the service delivery context to determine the required adaptations in order to enable efficient ubiquitous accessibility and personalization to the user situation and preferences. This paper presents technologies which have been identified useful for this purpose and how they are applied to deliver the functionality of the Adaptation Manager architecture, including ontology, OWL-DL, SWRL, reasoning and XSTL.

2008

Abstract Pervasive computing infrastructure makes it possible for mobile users to run software services on extremely heterogeneous and resource-constrained mobile devices. Heterogeneity and device limitedness creates serious problems for the development and deployment of mobile services that are able to run properly on the execution context and are able to ensures that users experience the ldquobestrdquo Quality of Service possible according to their needs and specific contexts of use.

International Journal of Computer & Information Science & Engineering 2 (3), 2008

Devices in a pervasive computing system (PCS) are characterized by their context-awareness. It permits them to provide proactively adapted services to the user and applications. To do so, context must be well understood and modeled in an appropriate form which enhance its sharing between devices and provide a high level of abstraction. The most interesting methods for modeling context are those based on ontology however the majority of the proposed methods fail in proposing a generic ontology for context which limit their usability and keep them specific to a particular domain. The adaptation task must be done automatically and without an explicit intervention of the user. Devices of a PCS must acquire some intelligence which permits them to sense the current context and trigger the appropriate service or provide a service in a better suitable form. In this paper we will propose a generic service ontology for context modeling and a context-aware service adaptation based on a service oriented definition of context.

Computers are no match to humans in deducing situational information from their environment and in using it in their interactions. The advent of Context-aware applications seems to offer a way out to the computer that is not context-sensitive. Context aware applications can adapt their behaviors according to the perceived context or situation, without explicit user intervention, thereby providing human-centric services. To simplify the complexity of developing applications, context aware framework, which introduces context awareness into the environment where the applications are executed, is highlighted to provide a homogeneous interface involving generic context management and adaptation solutions. In this paper, we cover a preliminary background, such as the principles of context, context awareness, context modeling, and context reasoning, is provided for a comprehensive understanding of context aware framework. On this basis, an overview of existed framework architectures is presented and their main features explained. Our contribution focuses on comparing and analyzing of the presented middleware architectures are performed based on prime criteria, which we have defined before. This comparison will be helpful to determine limits of existing context aware frameworks and identify future research opportunities in there frameworks.

2015

The introduction of new communication infrastructures such as Beyond 3rd Gen-eration (B3G) and the widespread usage of small computing devices are rapidly changing the way we use and interact with technology to perform everyday tasks. Ubiquitous networking empowered by B3G networking makes it possible for mobile users to access networked software services across continuously changing heteroge-neous infrastructures by resource-constrained devices. Heterogeneity and devices’ limitedness, create serious problems for the development and dynamic deployment of mobile applications that are able to run properly on the execution context and consume services matching with the users ’ expectations. Furthermore, the ever-changing B3G environment calls for applications that self-evolve according to con-text changes. Out of these problems, self-evolving adaptable applications are in-creasingly emerging in the software community. In this paper we describe how CHAMELEON, a declarative framework for...

Lecture Notes in Computer Science, 2006

A common trend in modern applications is the move towards more mobile, adaptive, customisable software. The evolution of software from static, invariant tools for narrow portions of a task to adaptive, open interaction frameworks is embodied in the use of a variety of technologies for creating a reconfigurable application. Perhaps the two most important techniques are Adaptive architectures and Ubiquitious Computing. However, many techniques employed merging these two technologies to form the vision of a truly ubiquitous, adaptive environment have so far failed to take full account of the expressive quality of both context and adaptivity. This paper presents a new, semantic interopration-based approach to creating context-informed adaptive applications that make maximum use of the rich content that can be found in both technologies.