The Java Context Awareness Framework (JCAF) – A Service Infrastructure and Programming Framework for Context-Aware Applications

Abstract. Context-awareness is a key concept in ubiquitous computing. But to avoid developing dedicated context-awareness sub-systems for specific applica-tion areas there is a need for more generic programming frameworks. Such frame-works can help the programmer to develop and deploy context-aware applications faster. This paper describes the Java Context-Awareness Framework – JCAF, which is a Java-based context-awareness infrastructure and programming API for creating context-aware computer applications. The paper presents the design principles behind JCAF, its runtime architecture, and its programming API. The paper presents some applications of using JCAF in three different applications and discusses lessons learned from using JCAF.

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 new framework for ubiquitous context-aware healthcare applications

Nowadays, there is a significant lack of generic application frameworks providing third party developers with the appropriate mechanisms for building ubiquitous contextaware healthcare applications over medical heterogeneous networks. In this paper, we propose a new framework integrating context-aware and security mechanisms with mechanisms that allow the ease exploitation of the core networks’ functionality to enable third party developers to build reliable and secure ubiquitous context-aware healthcare applications over medical heterogeneous networks

Intelligibility and user control of context-aware application behaviours

Context-aware applications adapt their behaviours according to changes in user context and user requirements. Research and experience have shown that such applications will not always behave the way as users expect. This may lead to loss of users' trust and acceptance of these systems. Hence, context-aware applications should (1) be intelligible (e.g., able to explain to users why it decided to behave in a certain way), and (2) allow users to exploit the revealed information and apply appropriate feedback to control the application behaviours according to their individual preferences to achieve a more desirable outcome. Without appropriate mechanisms for explanations and control of application adaptations, the usability of the applications is limited. This paper describes our on going research and development of a conceptual framework that supports intelligibility of model based context-aware applications and user control of their adaptive behaviours. The goal is to improve usability of context-aware applications

Towards social paradigms for mobile context-aware computing in smart cities

Ponència presentada a la 11ª Conferencia Ibérica de Sistemas y Tecnologías de Información (CISTI 2016) celebrada a Gran Canaria els dies 15-18 de juny de 2016Mobile context-aware computing is an essential component of the smart cities infrastructure. Attempts were made to develop a model that can effectively represent a system in device to support context-aware behavior. The purpose of this paper is to identify deficiencies of the previously developed model and propose solutions to improve it.The authors gratefully acknowledge funding from the European Commission through the GEO-C project (H2020- MSCA-ITN-2014, Grant Agreement Number 642332, http://www.geo-c.eu/). Carlos Granell has been partly funded by the Ramón y Cajal Programme (grant numbers RYC-2014- 16913

Programming support for time-sensitive adaptation in cyberphysical systems

Cyberphysical systems (CPS) integrate embedded sensors, actuators, and computing elements for controlling physical processes. Due to the intimate interactions with the surrounding environment, CPS software must continuously adapt to changing conditions. Enacting adaptation decisions is often subject to strict time requirements to ensure control stability, while CPS software must operate within the tight resource constraints that characterize CPS platforms. De- velopers are typically left without dedicated programming support to cope with these aspects. This results in either to neglect functional or timing issues that may potentially arise or to invest significant efforts to implement hand-crafted so- lutions. We provide programming constructs that allow de- velopers to simplify the specification of adaptive processing and to rely on well-defined time semantics. Our evaluation shows that using these constructs simplifies implementations while reducing developers’ effort, at the price of a modest memory and processing overhead

MultiS: A Context-Server for Pervasive Computing

AbstractContext-aware applications are capable of recognizing environmental changes and adapting their behavior to the new context. This process can be divided into three stages: monitoring, context recognition and adaptation. On the monitoring layer, raw information about the environment is collected from sensors. The context recognition layer processes the data acquired from the context and transforms it into information which can be useful for the adaptation process. With this information, the adaptation system can determine what behavior is correct for the application in each different context. This paper proposes a context server called MultiS, which has the goal of solving the problems arising from the context recognition layer, and which includes the following advantages: a) the production of new context data based on the information of several sensors and an ability to react to changes in the environment; b) definition of a composed language for the context data called CD-XML; c) support for mobility

Mobile cloud contextual awareness with the cloud personal assistant

This paper presents our efforts to bridge the gap between mobile context awareness, and mobile cloud services, using the Cloud Personal Assistant (CPA). The CPA is a part of the Context Aware Mobile Cloud Services (CAMCS) middleware, which we continue to develop. Specifically, we discuss the development and evaluation of the Context Processor component of this middleware. This component collects context data from the mobile devices of users, which is then provided to the CPA of each user, for use with mobile cloud services. We discuss the architecture and implementation of the Context Processor, followed by the evaluation. We introduce context profiles for the CPA, which influence its operation by using different context types. As part of the evaluation, we present two experimental context-aware mobile cloud services to illustrate how the CPA works with user context, and related context profiles, to complete tasks for the user

Context-oriented programming for adaptive wireless sensor network software

We present programming abstractions for imple- menting adaptive Wireless Sensor Network (WSN) software. The need for adaptability arises in WSNs because of unpredictable environment dynamics, changing requirements, and resource scarcity. However, after about a decade of research in WSN programming, developers are still left with no dedicated support. To address this issue, we bring concepts from Context-Oriented Programming (COP) down to WSN devices. Contexts model the situations that WSN software needs to adapt to. Using COP, programmers use a notion of layered function to implement context-dependent behavioral variations of WSN code. To this end, we provide language-independent design concepts to organize the context-dependent WSN operating modes, decoupling the ab- stractions from their concrete implementation in a programming language. Our own implementation, called CONESC, extends nesC with COP constructs. Based on three representative applica- tions, we show that CONESC greatly simplifies the resulting code and yields increasingly decoupled implementations compared to nesC. For example, by model-checking every function in either implementations, we show a ≈50% reduction in the number of program states that programmers need to deal with, indicating easier debugging. In our tests, this comes at the price of a maximum 2.5% (4.5%) overhead in program (data) memory

Sociology Paradigms for Dynamic Integration of Devices into a Context-Aware System

Ubiquitous and m obile context - aware computing is an essential component of the smart cities infrastructure. Widely available wireless networks, the maturity level of distributed computing and the increasing number of mobile devices have significantly influenced the human experience with computing. In the present paper, we discuss the need for a model that will be able to represent a formal structure of a context - aware system in a device . The core functionality of the model is expected to expose context - aware behaviour and support dynamic integration of mobile devices and context - aware behaviour. The major contribution of this work is to identify deficiencies of the existing model which is using the notions from sociology such as Role, Ownership and Responsibility.The authors gratefully acknowledge funding from the European Commission through the GEO-C project (H2020-MSCA-ITN-2014, Grant Agreement Number 642332, http://www.geo-c.eu/)