Noha Ibrahim

Semantic Service Substitution in Pervasive Environments

A computing infrastructure where everything is a service offers many new system and application possibilities. Among the main challenges, however, is the issue of service substitution for the application execution in such heterogeneous environments. An application would like to continue to execute even when a service disappears, or it would like to benefit from the environment by using better services with better QoS when possible. In this article, we define a generic service model and describe the equivalence relations between services considering the functionalities they propose and their non functional QoS properties. We define semantic equivalence relations between services and equivalence degree between non functional QoS properties. Using these relations we propose semantic substitution mechanisms upon the appearance and disappearance of services that fits the application needs. We developed a prototype as a proof of concept and evaluated its efficiency over a real use case.

Building Home Monitoring Applications: From Design to Implementation into The Amigo Middleware

The proliferation of smart communication devices based on technologies such as Radio-Frequency Identification (RFID) makes ubiquitous computing evolving at a frantic pace. This evolution leads to the development of applications, called monitoring applications, that offer a host of new functionalities based on context information provided by tagged entities. In this paper, we introduce a software architecture dedicated to monitoring applications and define a mapping to the Amigo middleware which is dedicated to ambient computing. We illustrate our approach by developing two real-size applications for child monitoring and object reminder. In these experiments, our approach have demonstrated its usability and ease of programming.

ROCS: a remotely provisioned OSGi framework for ambient systems

One of the challenges of ambient systems lies in providing all the available services of the environment to the ambient devices, even if they do not physically host those services. Although this challenge has come to find a solution through cloud computing, there are still few devices and operating systems that enable applications execution by only uploading the required components into the runtime environment. The ROCS (Remote OSGi Caching Service) framework is a novel proposal which relies on a heavy-weighted standard Java/OSGi stack. It is distributed between class servers and ambient devices to provide full functionalities to resource-constrained environments. The ROCS framework provides improvements in two areas. First, it defines a minimal bootstrap environment that runs a standard Java/OSGi stack. Secondly, it provides an architecture for loading any necessary missing class from remote servers into memory at runtime. Our first results show similar performances when classes are either remotely downloaded into the main memory from a local network or from a flash drive. These results suggest a way to design minimalistic middleware that dynamically obtain their applications from the network as a first step towards cloud-aware operating systems.

C-ANIS: a contextual, automatic and dynamic service-oriented integration framework

Ubiquitous computing environments are highly dynamic by nature. Services provided by different devices can appear and disappear as, for example, devices join and leave these environments. This article contributes to the handling of this dynamicity by discussing service integration in the context of service-oriented architectures. We propose C-ANIS: a Contextual, Automatic and dyNamic Integration framework of Services. C-ANIS distinguishes two different approaches to service integration: automatic integration and on-demand integration. Automatic integration automatically extends the capabilities of an existing service S, leaving the interface of S unchanged. On-demand integration builds a new service on request from a list of given services. We have implemented C-ANIS based on the OSGi/Felix framework and thereby demonstrated the feasibility of these two service integration concepts. We have also implemented a toolkit providing two different techniques to realize the automatic and on-demand service integration concepts: Redirection, i.e. calling interfaces and replication, i.e. copying implementations of services1.

Context-aware Specialization of Semantic Rules for choosing Services in Pervasive Environments

The development of many highly dynamic environments, such as pervasive environments, has modified the behavior of users and consequently, their expectations of systems and applications executed in these environments. Thus, a user can connect to different places, and, each time, would like to use the functionalities offered by the physically or logically close environment. This paper proposes a novel approach for specializing strategies for choosing, and then using services in a pervasive environment. To the best of our knowledge, strategies for the use of services in a pervasive environment are dynamic but ad-hocly defined during the development phase. By changing the context, the strategy can change and be replaced by another one predefined in the application development phase. Our idea is to provide a context-aware mechanism which is able to adapts dynamically the condition and action parts of the rule of the strategy to the context without the need to specify how, during the development of applications. Only a general strategy is defined in the development phase. At run time, a dynamic specialization adapted to the context, provides a specialized strategy from the general one.

ANIS: a negotiated integration of services in distributed environments

The development of highly dynamic distributed environments modifies the runtime behavior of applications Applications tend to use services available everywhere in the environment and would like to, whenever it is possible and/or needed, integrate services offered by the local environment In particular, if no single service can satisfy the functionality required by the application, combining existing services together should be a possibility in order to fulfill the request. In this article, we propose ANIS: A Negotiated Integration System Our system provides a framework including a set of integration management interfaces – Integrable, Negotiable, IntegrationLifeCycle – and the tools implementing these interfaces These tools offer different techniques of integration (local/remote composition, local/remote weaving, deployment by downloading/uploading), negotiation by contracts and the capability to manage the life cycle of the integration. A prototype based on Java platform and OSGi technology is implemented as a proof-of-concept to demonstrate the potential of ANIS.