CARISMA: Context-Aware Reflective mIddleware System for Mobile Applications

TLDR

Mobile devices are widely used and increasingly networked, enabling distributed applications that must adapt to changing context such as bandwidth, battery, connectivity, and service availability, and these adaptations can involve conflicting policies. The paper aims to classify conflict types in mobile computing and argue that they must be resolved at execution time rather than statically during design. CARISMA is a reflective middleware that offers primitives for policy‑based context handling, implements a sealed‑bid auction method to resolve policy conflicts at runtime, and demonstrates this approach in a distributed mobile application. Evaluation shows that conflict resolution incurs no significant overhead, validating the practicality of the approach.

Abstract

Mobile devices, such as mobile phones and personal digital assistants, have gained wide-spread popularity. These devices will increasingly be networked, thus enabling the construction of distributed applications that have to adapt to changes in context, such as variations in network bandwidth, battery power, connectivity, reachability of services and hosts, etc. In this paper, we describe CARISMA, a mobile computing middleware which exploits the principle of reflection to enhance the construction of adaptive and context-aware mobile applications. The middleware provides software engineers with primitives to describe how context changes should be handled using policies. These policies may conflict. We classify the different types of conflicts that may arise in mobile computing and argue that conflicts cannot be resolved statically at the time applications are designed, but, rather, need to be resolved at execution time. We demonstrate a method by which policy conflicts can be handled; this method uses a microeconomic approach that relies on a particular type of sealed-bid auction. We describe how this method is implemented in the CARISMA middleware architecture and sketch a distributed context-aware application for mobile devices to illustrate how the method works in practice. We show, by way of a systematic performance evaluation, that conflict resolution does not imply undue overheads, before comparing our research to related work and concluding the paper.