Context-aware and resource efficient sensing infrastructure for context-aware applications

Middleware for wireless sensor networks and middleware for context-aware applications both provide information abstraction and programming support for gathering, pre-processing, and managing sensor data. However the former mostly concentrates on optimising the operations of the resource constrained hardware and simplifying access to the raw sensor data while the latter focuses on gathering sensor data, pre-processing it to the abstract context information required by the applications and providing reasoning on this data. In this paper, we explore the idea of enhancing middleware for context-aware applications with solutions from sensor networks middle ware to allow resource efficient and contextaware management of sensing infrastructure. The decisions on which sensor data needs to be delivered to the middleware for evaluation are based on current contextual situations. The approach allows to trade the level of confidence in context information for resource efficiency in context provisioning without a detrimental effect on the functionality of contextaware applications. © 2010 IEEE

Bringing Context-Awareness to Applications in Ad Hoc Mobile Networks

Context-aware mobile applications require constant adapta-tion 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 a middleware infrastructure for sensing, collect-ing, and providing context information to applications. In this paper, we demonstrate the feasibility of providing such a middleware that 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 opportunis-tically encountered components. We also discuss the novel context-aware abstractions the middleware provides and the programming knowledge necessary to write applications using our middleware. Finally, we provide examples demonstrating the flexibility of the infrastructure and its abil-ity to support differing tasks from a wide variety of application domains

A novel middleware for the mobility management over the Internet

The features of mobility, which enormously impact on how communication is evolving into the future, represent a particular challenge in today’s wireless networking research. After an identification and evaluation of the gap between the discontinuities of the communication service inherent to the physical layer of mobile networks and the continuity requirements issue from the stream centric multimedia applications, we propose a novel middleware 3MOI (Middleware for the Mobility Management Over the Internet) which can perform efficient and context-aware mobility management and satisfy new mobility requirements such as dynamical location management, fast handover, and continuous connection support

An adaptive modelling infrastructure for context-aware mobile computing

Context provides information about the present status of people, places, things, network and devices in the environment. Context-awareness refers to the use of context information for an application to adapt its functionality to the current context of use. Development of context-aware applications is inherently complex. Previous researches on mobile computing emphasize on programmable interfaces for development of context-aware systems. There are limited researches that emphasize on the modelling aspects of adaptive applications. This research aims at developing a complete infrastructure for development of context-aware applications. The infrastructure consists of a middleware for context-aware application development that is supported by a set of context information modelling and reasoning facilities. It aims at extending the capabilities of context-aware middleware infrastructures by incorporating novel approaches to model context and situations under uncertainty. This thesis addresses the key challenges in context-aware computing by a complete infrastructure that aims at achieving the following: (1) support for fuzzy composition of high level context abstraction from low level detector context, and fuzzy-based inference mechanisms, (2) support for mobile services that can be dynamically composed and migrated with reference to adaptation requirements for different context situations, (3) support for modelling of adaptation components and entities

MobiPADS: a reflective middleware for context-aware mobile computing

distributed computing services that essentially abstract the underlying network services to a monolithic “black box. ” In a mobile operating environment, the fundamental assumption of middleware abstracting a unified distributed service for all types of applications operating over a static network infrastructure is no longer valid. In particular, mobile applications are not able to leverage the benefits of adaptive computing to optimize its computation based on current contextual situations. In this paper, we introduce the Mobile Platform for Actively Deployable Service (MobiPADS) system. MobiPADS is designed to support context-aware processing by providing an executing platform to enable active service deployment and reconfiguration of the service composition in response to environments of varying contexts. Unlike most mobile middleware, MobiPADS supports dynamic adaptation at both the middleware and application layers to provide flexible configuration of resources to optimize the operations of mobile applications. Within the MobiPADS system, services (known as mobilets) are configured as chained service objects to provide augmented services to the underlying mobile applications so as to alleviate the adverse conditions of a wireless environment. Index Terms—Middleware, mobile applications, mobile computing support services, mobile environments.

A model for context awareness for mobile applications using multiple-input sources

Context-aware computing enables mobile applications to discover and benefit from valuable context information, such as user location, time of day and current activity. However, determining the users’ context throughout their daily activities is one of the main challenges of context-aware computing. With the increasing number of built-in mobile sensors and other input sources, existing context models do not effectively handle context information related to personal user context. The objective of this research was to develop an improved context-aware model to support the context awareness needs of mobile applications. An existing context-aware model was selected as the most complete model to use as a basis for the proposed model to support context awareness in mobile applications. The existing context-aware model was modified to address the shortcomings of existing models in dealing with context information related to personal user context. The proposed model supports four different context dimensions, namely Physical, User Activity, Health and User Preferences. A prototype, called CoPro was developed, based on the proposed model, to demonstrate the effectiveness of the model. Several experiments were designed and conducted to determine if CoPro was effective, reliable and capable. CoPro was considered effective as it produced low-level context as well as inferred context. The reliability of the model was confirmed by evaluating CoPro using Quality of Context (QoC) metrics such as Accuracy, Freshness, Certainty and Completeness. CoPro was also found to be capable of dealing with the limitations of the mobile computing platform such as limited processing power. The research determined that the proposed context-aware model can be used to successfully support context awareness in mobile applications. Design recommendations were proposed and future work will involve converting the CoPro prototype into middleware in the form of an API to provide easier access to context awareness support in mobile applications

Reflective mobile middleware for context-aware applications

The increasing popularity of mobile devices, such as mobile phones and personal digital assistants, and advances in wireless networking technologies, are enabling new classes of applications that present challenging problems to application designers. Applications have to be aware of, and adapt to, variations in the execution context, such as fluctuating network bandwidth and decreasing battery power, in order to deliver a good quality of service to their users. We argue that building applications directly on top of the network operating system would be extremely tedious and error-prone, as application developers would have to deal with these issues explicitly, and would consequently be distracted from the actual requirements of the application they are building. Rather, a middleware layered between the network operating system and the application should provide application developers with abstractions and mechanisms to deal with them. We investigate the principle of reflection and demonstrate how it can be used to support context-awareness and dynamic adaptation to context changes. We offer application engineers an abstraction of middleware as a dynamically customisable service provider, where each service can be delivered using different policies when requested in different contexts. Based on this abstraction, current middleware behaviour, with respect to a particular application, is reified in an application profile, and made accessible to the application for run-time inspection and adaptation. Applications can use the meta-interface that the middleware provides to change the information encoded in their profile, thus tailoring middleware behaviour to the user's needs. However, while doing so, conflicts may arise; different users may have different quality-of-service needs, and applications, in an attempt to full these needs, may customise middleware behaviour in conflicting ways. These conflicts have to be resolved in order to allow applications to come to an agreement, and thus be able to engage successful collaborations. We demonstrate how microeconomic techniques can be used to treat these kinds of conflicts. We offer an abstraction of the mobile setting as an economy, where applications compete to have a service delivered according to their quality-of-service needs. We have designed a mechanism where middleware plays the role of the auctioneer, collecting bids from the applications and delivering the service using the policy that maximises social welfare; that is, the one that delivers, on average, the best quality-of-service. We formalise the principles discussed above, namely reflection to support context-awareness and microeconomic techniques to support conflict resolution. To demonstrate their effectiveness in fostering the development of context-aware applications, we discuss a middleware architecture and implementation (CARISMA) that embed these principles, and report on performance and usability results obtained during a thorough evaluation stage

Correlating context-awareness and mutation analysis for pervasive computing systems

Proceedings of the International Conference on Quality Software, 2010, p. 151-160Pervasive computing systems often use middleware as a means to communicate with the changing environment. However, the interactions with the context-aware middleware as well as the interactions among applications sharing the same middleware may introduce faults that are difficult to reveal by existing testing techniques. Our previous work proposed the notion of context diversity as a metric to measure the degree of changes in test inputs for pervasive software. In this paper, we present a case study on how much context diversity for test cases relates to fault-based mutants in pervasive software. Our empirical results show that conventional mutation operators can generate sufficient candidate mutants to support test effectiveness evaluation of pervasive software, and test cases with higher context diversity values tend to have higher mean mutation scores. On the other hand, for test cases sharing the same context diversity, their mutation scores can vary significantly in terms of standard derivations © 2010 IEEE.published_or_final_versio

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