A Rule Based Publish/Subscribe Context Dissemination Middleware

Abstract

Context information is vital data coming from mobile devices to add a value for the application execution. Such applications are called context-aware or context-sensitive applications. To enable context-aware applications in a distributed environment, first the context raw data is measured from sensors. After interpreting and structuring the data, the context objects have to be disseminated all over the distributed system. This paper introduces a context dissemination middleware based on a mobile Web Service framework. It eases the development of context aware applications by providing an abstraction layer hiding complex protocols. In addition, the protocols are optimized in terms of reducing latencies and network load. Moreover, to provide observation (monitoring) service of arbitrary context information, a rule description (policy) language has been designed, developed and structured. Web services eventing has been implemented for sending event notifications. The architecture and a prototypical implementation of the context middleware is presented in detail.

Adaptive context monitoring in heterogeneous environments

“…The mobile device only forwards context information from context sensors to the server KB and receives the processed monitoring results, instead of processing the contexts locally. To effectively handle the wide non-redundant contexts in the service-side KB, manageable rule-based policies are made to be a part of the KB [1], and would be adapted to suit the current conditions. By employing this overlay model we take the load off mobile devices.…”

“…Context awareness plays a vital role in heterogeneous networks and systems, such as Ambient Networks (AN), and is a proven efficient approach for adapting network services [1] [2][3] [4]. Monitoring of context information to efficiently enable context-awareness in various applications is being under vigorous research.…”

“…Alongside context awareness, the main theories employed in our context monitoring scheme include: Ambient networks [5], Overlay Networks [6], Agents [7], and Policies [1]. Our context monitoring scheme employs a novel overlay-based framework in ANs.…”