Context-Aware Adaptation for Mobile Devices

International audienceThis paper discusses the problem of content adaptation for mobile devices. The adaptation considers the context of the client and also the environment where the client request is received. A device independent model is defined and used in order to achieve automatic adaptation of the content based on its semantic and the capabilities of the target device. Our system includes a context description model and a client repository and offers device contexts management and querying functions. The proposed system uses the XQuery language to query the profiles and delivers the results in the form of SOAP services

Context-Aware Adaptation of Mobile Multimedia Presentations

With increasing capabilities of mobile devices, the number of mobile multimedia services grows steadily. Usage of multimedia services and especially the presentation of multimedia content is more challenging in a mobile environment than on stationary devices due to the diversity of mobile devices and their parameters, the sparse resources of the air interface or the changing context. This position paper introduces an approach for context-aware adaptation of mobile multimedia presentations. For this, a middleware architecture is proposed that performs an automatic and distributed adaptation process: while the server provides a pre-processing of the content, the client completes the overall adaptation. To support this task, the Adaptation Rule Language (ARL) was developed which is introduced in this paper as well

A middleware service for coordinated adaptation of communication services in groups of devices

Abstract—Recent research in pervasive computing has shown that context-awareness and dynamic adaptation are fundamental requirements of mobile distributed applications. However, most approaches that focus on context-aware dynamic adaptation use only the context information available at the mobile device to trigger a local adaptation. However, for distributed collaborative applications this is clearly insufficient, since a same adaptation has to be done, in synch, at all mobile devices of the group, and hence should also be based on a commonly agreed context. Therefore, for such kinds of applications one requires mechanisms and protocols to exchange the context information among the devices and to coordinate of the adaptation operations at a group of mobile device. In this paper we present a middleware service for coordinated adaptation of communication services in groups of devices. At each device this adaptation is achieved with minimal disruption for the application’s remote interactions. This middleware service is based on the notion of global context and a generic protocol for global context election and synchronization of the adaptation steps, which we called Moratus. Our middleware service was implemented using JGroups and evaluated for groups of up to 30 devices, showing acceptable latency for groups of such size. I

Enabling Context-Aware Web Services: A Middleware Approach for Ubiquitous Environments

In ubiquitous environments, mobile applications should sense and react to environmental changes to provide a better user experience. In order to deal with these concerns, Service-Oriented Architectures (SOA) provide a solution allowing applications to interact with the services available in their surroundings. In particular, context-aware Web Services can adapt their behavior considering the user context. However, the limited resources of mobile devices restrict the adaptation degree. Furthermore, the diverse nature of context information makes difficult its retrieval, processing and distribution. To tackle these challenges, we present the CAPPUCINO platform for executing context-aware Web Services in ubiquitous environments. In particular, in this chapter we focus on the middleware part that is built as an autonomic control loop that deals with dynamic adaptation. In this autonomic loop we use FraSCAti, an implementation of the Service Component Architecture (SCA) specification, as the execution kernel for Web Services. The context distribution is achieved with SPACES, a flexible solution based on REST (REpresentational State Transfer ) principles and benefiting from the COSMOS (COntext entitieS coMpositiOn and Sharing ) context manage- ment framework. The application of our platform is illustrated with a mobile commerce application scenario that combines context-aware Web Services and social networks

Odin: Context-Aware Middleware for Mobile Services

Abstract—Mobile devices such as smart phones are increas-ing permeating society. With strides in computational power, coupled with the ability to connect to other small devices, smart phones are able to host novel services. To address the repetitive problems associated with mobile service development, namely service reachability, scalability and availability, we have developed Odin, which is a middleware platform for mobile service provisioning. Beyond providing a provisioning solution, Odin conserves scarce resources such as network bandwidth and device power supply. However, Odin has previously lacked an ability to take into account operational context. In this paper, we present context-aware extensions to Odin that further optimise resource usage. Augmented with support for context types that include location, performance, power and network, Odin is able to propagate context information to applications and dynamic adapt the middleware’s behaviour. Novelty of the work lies in a solution whose device overhead is very low, and one that offers a coherent approach to context dis-semination and adaptation. Based on quantitative evaluation, context-aware Odin’s low overhead is demonstrated along with significant gains in resource conservation. I

A Software Engineering Perspective on Context-Awareness in Ad Hoc Mobile Environments

Context-aware mobile applications require constant adaptation to their changing environments. Technological advancements have increased the pervasiveness of mobile computing devices such as laptops, handhelds, cellular phones, and embedded sensors. The sheer amount of context information necessary for adaptation places a heightened burden on application developers as they must manage and utilize vast amounts of data from diverse sources. Facilitating programming in this data-rich environment requires an infrastructure for sensing, collecting, and providing context information to applications. In this paper, we demonstrate the feasibility of providing such an infrastructure. It allows programmers to focus on high-level interactions among programs and to employ declarative abstract specifications of context in settings that exhibit high levels of mobility and transient interactions with opportunistically encountered components. We also discuss the novel context-aware abstractions we implemented and the programming knowledge necessary to write applications using our middleware. Finally, we provide examples that demonstrate the flexibility of the infrastructure and its ability to support a variety of applications

"InstantSocial" – Implementing a Distributed Mobile Multi-user Application with Adaptation Middleware

In this position paper we explore how new capabilites of mobile devices could be used to setup distributed multi-user mobile applications with potentially high interest for end users. We describe an example of such an application by transposing Internet social network trends and principles to a mobile ad hoc environment. Then we present a tentative design and implentation sketch of this application in terms of the MUSIC context-aware adaptation middleware we are currently developing

Context-Aware Computation Offloading for Mobile Cloud Computing: Requirements Analysis, Survey and Design Guideline

AbstractAlong with the rise of mobile handheld devices the resource demands of respective applications grow as well. However, mobile devices are still and will always be limited related to performance (e.g., computation, storage and battery life), context adaptation (e.g., intermittent connectivity, scalability and heterogeneity) and security aspects. A prominent solution to overcome these limita- tions is the so-called computation offloading, which is the focus of mobile cloud computing (MCC). However, current approaches fail to address the complexity that results from quickly and constantly changing context conditions in mobile user scenarios and hence developing effective and efficient MCC applications is still challenging. Therefore, this paper first presents a list of re- quirements for MCC applications together with a survey and classification of current solutions. Furthermore, it provides a design guideline for the selection of suitable concepts for different classes of common cloud-augmented mobile applications. Finally, it presents open issues that developers and researchers should be aware of when designing their MCC-approach

Design and implementation of a Context-Aware Health Service Platform (CAHS)

Computers are no match to humans in deducing situational information from their environment and in using it in their interactions. The advent of the context-aware applications seems to offer a way out to the computer that is not context-sensitive. The 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. This papier has focused on the design of Context-Aware Health Services (CAHS) platform, which provide a health applications framework embedded on mobile devices. Our proposed platform is capabilities for context manager and adaptations according to context changes. It is designed to base on the SOA principles for achieving a flexible and dynamic architecture