Nowadays, numerous journals and conferences have published articles related to context-aware systems, indicating many researchers' interest. Therefore, the goal of this paper is to review the works that were published in journals, suggest a new classification framework of context-aware systems, and explore each feature of classification framework. This paper is based on a literature review of context-aware systems from 2000 to 2007 using a keyword index and article title search. The classification framework is developed based on the architecture of context-aware systems, which consists of the following five layers: concept and research layer, network layer, middleware layer, application layer and user infrastructure layer. The articles are categorized based on the classification framework. This paper allows researchers to extract several lessons learned that are important for the implementation of context-aware systems.

Context-aware systems

The capacity to gather and timely deliver to the service level any relevant information that can characterize the service-provisioning environment, such as computing resources/capabilities, physical device location, user preferences, and time constraints, usually defined as context-awareness, is widely recognized as a core function for the development of modern ubiquitous and mobile systems. Much work has been done to enable context-awareness and to ease the diffusion of context-aware services; at the same time, several middleware solutions have been designed to transparently implement context management and provisioning in the mobile system. However, to the best of our knowledge, an in-depth analysis of the context data distribution, namely, the function in charge of distributing context data to interested entities, is still missing. Starting from the core assumption that only effective and efficient context data distribution can pave the way to the deployment of truly context-aware services, this article aims at putting together current research efforts to derive an original and holistic view of the existing literature. We present a unified architectural model and a new taxonomy for context data distribution by considering and comparing a large number of solutions. Finally, based on our analysis, we draw some of the research challenges still unsolved and identify some possible directions for future work.

/pdf/a-survey-of-context-data-distribution-for-mobile-ubiquitous-5bopu05rxl.pdf

A survey of context data distribution for mobile ubiquitous systems

During the last years, a continuous convergence and fusion of computing and networking systems is stressed in the ICT research community. Context awareness appears to be a major research "glue-point" of such kind of heterogeneous environments' integration. In this survey paper, we aim to assemble all the "puzzle-pieces" of the emerging research area of Context Aware Mobile and Wireless Networking (CAMoWiN) in order to provide the reader a holistic representation of the work having been done in the past emphasizing in recent research efforts. A precise definition of abstract Context Aware (CA) functionalities together with a clear classification of related state-of-the-art proposals are provided in the form of a proposed taxonomy scheme per CA functionality. Each taxonomy scheme can also serve as a sufficiently general framework permitting the easy classification of novel CAMoWiN solutions emerging in the near future. Therefore, our study not only defines all the possible components of a CAMoWiN architecture and clearly points out the similarities and differences of all research efforts in the field but also evaluates future research trends and paves the way for the researchers to work beyond the concepts investigated in this work. Finally, apart from identifying the open challenges, which arise when applying traditional concepts of pervasive computing to mobile and wireless networks, we further map them to the Mobile Cloud Computing paradigm, whose concepts appear to be very promising regarding next generation networking and computing environments' integration.

A Survey on Context-Aware Mobile and Wireless Networking: On Networking and Computing Environments' Integration

The Internet of Things (IoT) refers to extending the Internet to devices such as home appliances, consumer electronics, and sensor networks. As multiple heterogeneous devices attempt to create area networks, one of the major challenges is the interoperability and com-posability of their services. The traditional way to address interoperability is to define standards; however, there are many standards and specifications that are incompatible with each other. In this paper we propose an application layer solution for interoperability. The key idea is to utilize device semantics provided by existing specifications and dynamically wrap them in our middleware into semantic services. Next, with the help of Semantic Web technologies, users can create and then execute complex tasks involving multiple heterogeneous devices. We demonstrate how our framework automates interoperability without any modifications to existing standards, devices, or technologies, while providing to the user an intuitive semantic interface with services that can be executed by combining devices in the network.

Semantic middleware for the Internet of Things

Designing viable business models for context-aware mobile services

The acceptance of next-generation mobile communication systems depends to a large extent on the services and applications that can be offered to customers. Tailoring the services to actual user needs is considered to be crucial for the success of future wireless technology. The individual user, "I", has to be put in the center of service provisioning. In this article, we report the work developed by the Working Group 2 of the Wireless World Research Forum on a service infrastructure framework for the future wireless world. Major service capabilities such as personalization, ambient awareness, and adaptability are described along with a reference model focusing in I-centric communication.

I-centric communications: personalization, ambient awareness, and adaptability for future mobile services

Service platform functions are enablers of adaptive communication services and applications that hide the heterogeneity of the infrastructure, manage personal reachability, manage implicit context, and adapt modality to the context. Furthermore, they can offer a diversity of services, whereby an optimal tradeoff can be made for end users in comfort, cost, security, and mobility. We consider the enablers of context-aware services in distributed environments and present a context management framework that is generic through its hierarchic ordering of context sources and extensible with multiple reasoning realizations. The article focuses on the architectural principles and reasoning methods of the framework

H. van Kranenburg

Papers

I-centric communications: personalization, ambient awareness, and adaptability for future mobile services

A context management framework for supporting context-aware distributed applications

Amigo: Ambient Intelligence for the networked home environment