Interoperating Context Discovery Mechanisms

Context-Aware applications adapt their behaviour to the current situation of the user. This information, for instance user location and user availability, is called context information. Context is delivered by distributed context sources that need to be discovered before they can be used to retrieve context. Currently, multiple context discovery mechanisms exist, exhibiting heterogeneous capabilities (e.g. communication mechanisms, and data formats), which can be available to context-aware applications at arbitrary moments during the ap-plication’s lifespan. In this paper, we discuss a middleware mechanism that en-ables a (mobile) context-aware application to interoperate transparently with different context discovery mechanisms available at run-time. The goal of the proposed mechanism is to hide the heterogeneity and availability of context discovery mechanisms for context-aware applications, thereby facilitating their development

A Rule-Based Approach Towards Context-Aware User Notification Services

Pervasive Computing is the vision of technology that is invisibly embedded in our natural surroundings. Users are offered unobtrusive services that require minimal attention. In this paper the Awareness and Notification Service (ANS) is presented that enables to rapidly build applications that inform users about their environment. Additionally, the service offers notifications tailored to the user's preferences and current context. ANS takes a rule based approach based on the Event-Condition-Action pattern. Users specify when and what should be notified to them by using a convenient ANS rule language. This flexible mechanism allows to rapidly develop applications that provide context-aware notifications without the need to write programming code to activate rules, nor to implement personalized notifications

Controlling services in a mobile context-aware infrastructure

Context-aware application behaviors can be described as logic rules following the Event-Control-Action (ECA) pattern. In this pattern, an Event models an occurrence of interest (e.g., a change in context); Control specifies a condition that must hold prior to the execution of the action; and an Action represents the invocation of arbitrary services. We have defined a Controlling service aiming at facilitating the dynamic configuration of ECA rule specifications by means of a mobile rule engine and a mechanism that distributes context reasoning activities to a network of context processing nodes. In this paper we present a novel context modeling approach that provides application developers and users with more appropriate means to define context information and ECA rules. Our approach makes use of ontologies to model context information and has been developed on top of web services technology

Application of a conceptual framework for the modelling and execution of clinical guidelines as networks of concurrent processes

We present a conceptual framework for modelling clinical guidelines as networks of concurrent processes. This enables the guideline to be partitioned and distributed at run-time across a knowledge-based telemedicine system, which is distributed by definition but whose exact physical configuration can only be determined after design-time by considering, amongst other factors, the individual patient's needs. The framework was applied to model a clinical guideline for gestational diabetes mellitus and to derive a prototype that executes the guideline on a smartphone. The framework is shown to support the full development trajectory of a decision support system, including analysis, design and implementation

Supporting the developers of context-aware mobile telemedicine applications

Telemedicine, which is defined as providing healthcare and sharing of medical knowledge over distance using telecommunication means, is a promising approach to improve and enhance the healthcare provisioning process. However, only recently, technology has evolved (i.e. miniaturization of high power mobile devices that can use high bandwidth mobile communication mechanisms) such that feasible advanced telemedicine applications can be developed. Current telemedicine systems offer proprietary solutions that are used in specific disease domains. For the acceptation, rapid development and introduction of novel and advanced telemedicine applications, there is a need for architectural mechanisms that supports developers in rapidly developing such telemedicine applications. The research discussed in this paper, focuses on the development of such mechanisms. I would like to thank my supervisors M. van Sinderen and A. van Halteren for their contributions to my research and this paper. This work is part of the Freeband AWARENESS Project (http://awareness.freeband.nl). Freeband is sponsored by the Dutch government under contract BSIK 03025

Dynamic Context Bindings, Infrastructural Support for Context-aware Applications

The world is increasingly equipped with high-capacity, interconnected, mobile and embedded computing devices. Context-awareness provides an attractive approach to personalize applications such that they better suit the user’s needs in this rich computing environment. Context-aware applications use context information, offered by context sources, to adapt their behavior to the situation at hand. The exchange of context information requires an association between a context consuming context-aware application and suitable context producing context sources. We call these associations ‘context bindings’. Developing context-aware applications is complex due to some intrinsic characteristics of context sources. Firstly, context sources are distributed. Consequently, creating a context binding requires some form of discovery and selection of context sources. Secondly, context sources are arbitrary available during the life-span of the application. This makes a binding hard to maintain. Finally, context sources offer context information with a fluctuating quality. This makes a binding possibly unsuitable for the application. Currently, developers need to spend considerable effort to develop application code to create and maintain required context bindings, which can deal with these complexities. This thesis provides insights in the generic characteristics of context-aware applications and their development process. We propose an abstraction, called the Context Binding Transparency. This transparency has as goal to mask the complexities of creating and maintaining context bindings for the application developer. In this way, we facilitate the development process of context-aware applications. The responsibility for creating and maintaining context bindings is relieved from the application developer and is shifted to a context binding infrastructure. This enables application developers to focus on the development of primary application logic rather than the logic needed to create and maintain context bindings. The application developer interacts with the context binding infrastructure using context retrieval and publishing services, and a context requirement specification language. This language enables application developers to specify their requirement at a high level of abstraction rather than in programming code. In this thesis, we propose a realization of such a context requirement specification language, coined the Context Binding Description Language (CBDL). This language is developed to be generic for a broad range of context-aware applications. Additionally, we propose a realization of a context binding infrastructure called the Context-Aware Component Infrastructure (CACI). This infrastructure realizes a context binding transparency and is composed of a context binding mechanism and a context discovery interoperability mechanism. The context binding mechanism uses CBDL documents, specified by the application developers, to create and maintain context bindings on behalf of the application. The process of creating a binding consists of discovery of context sources at available context discovery mechanisms, selection of suitable context sources, establishment of a binding of the application to these context sources, and maintenance of this binding. Maintenance of a context binding includes re-binding to other suitable context sources in case of lost or (re-)appearing context sources and fluctuating quality of context. This thesis gives an example of a possible rebinding algorithm. The context discovery interoperability mechanism enables context-aware applications to interoperate transparently with different context discovery mechanisms available in the application environment. The goal of the interoperability mechanism is to hide the heterogeneity and fluctuating availability of context discovery mechanisms for context-aware applications. The context discovery interoperability mechanism is a supporting mechanism for the context binding mechanism. It can also be used independently by context-aware applications that do not leverage from the context binding mechanism. We have created a proof-of-concept prototype of CACI, using the OSGi component framework. The prototype includes implementations of the context binding mechanism and the context discovery interoperability mechanism. Evaluation of the proposed context binding transparency and infrastructure consists of a user survey and a comparison on the development effort and software quality of a Telemedicine case implementation with and without CACI. The survey indicated a general interest of possible users in the features of the context binding transparency. The case implementations indicated a possible improvement in the development process of higher quality context-aware applications when using a context binding infrastructure. This research stresses that the availability of context information and the quality of this information highly influences the development of context-aware applications. By using a middleware infrastructure to support the creation and maintenance of context bindings, the development of higher quality context-aware applications can be simplified

SimuContext: Simply Simulate Context

Testing and demonstrating context-aware applications is challenging. Gathering and using ‘life’ contextual information for these purposes, often requires significant extra development effort. Furthermore, repeating tests and demonstrations of context-aware applications that use ‘life’ context information, in a controlled way, is difficult or often impossible to achieve. This paper presents a context simulation framework, called SimuContext, which abstracts from the complexity of interfacing with physical context sources and facilitates testing and demonstrating context-aware applications in a controlled way

Context-aware QoS provisioning for an M-health service platform

Inevitably, healthcare goes mobile. Recently developed mobile healthcare (i.e. m-health) services allow healthcare professionals to monitor a mobile patient�s vital signs and provide feedback to this patient anywhere and any time. Due to the nature of current supporting mobile services platforms, mhealth services are delivered with a best-effort, i.e., there are no guarantees on the delivered quality of service (QoS). In this paper, we argue that the use of contextual information in an mhealth services platform improves the delivered QoS. We give a first attempt to merge contextual information with a QoS-aware mobile services platform in the m-health services domain. We illustrate this with an epilepsy tele-monitoring scenario

A Rule-Based Approach Towards Context-Aware User Notification Services

Pervasive Computing is the vision of technology that is invisibly embedded in our natural surroundings. Users are offered unobtrusive services that require minimal attention. In this paper the Awareness and Notification Service (ANS) is presented that enables to rapidly build applications that inform users about their environment. Additionally, the service offers notifications tailored to the user’s preferences and current context. ANS takes a rule based approach based on the Event- Condition-Action pattern. Users specify when and what should be notified to them by using a convenient ANS rule language. This flexible mechanism allows to rapidly develop applications that provide context-aware notifications without the need to write programming code to activate rules, nor to implement personalized notifications

Grounded Contextual Reasoning enabling Innovative Mobile Services

This paper reflects our findings on the technological feasibility of a mobile service scenario. We will show that despite the scenario being quite ordinary for endusers, the required service support functionality is rather complex. The realisation hinges on intricate grounded contextual reasoning about location information, user profiles and other situational context information. In particular, existing engineering methods and state-of-the-art technologies very well enable, for example, timely warning of a sales manager, who is late for and on his way to a business meeting. Furthermore, such techniques readily enable recommending the ‘best’ alternative travel schemes such that he arrives in time for his meeting. We report on our findings with implementing a sophisticated location reasoner of such a commuter-assistant that ultimately aligns commuting and meeting preference schemes of the sales manager