Research On Technologies Of Design And Implementation For Activity-Oriented Context-Aware (AOCA) Application Systems

Pervasive/ubiquitous computing is a new computing paradigm which attempts to embed abundant computing resources into the environment. For users, such kind of computing is ubiquitous and transparent. The improvement of the software and hard-ware technologies makes pervasive computing possible, thus causing extensive atten-tion from both academic and industrial field. One of the focuses of such researches is called context-awareness, an essential ability of pervasive computing system. To be specific, it refers to the ability for the computing system can sense the environment, and react based on it. From the software methodology perspective, studies have been carried out on comprehending the notion of context, developing context-aware appli-cations, and ways of supporting the runtime of such applications. This research area is in a booming phase.This paper considers a typical kind of application with the above computing paradig-m, namely activity-oriented context-aware (AOCA) applications. Users of such appli-cations perform various activities of daily life in a smart space autonomously, and the function of AOCA applications is to provide environment support for the activi-ties. Users’ requirements of these applications are represented as the constraints for the environment. These constraints, in the meantime, are highly dependent on users’ activities. In pervasive computing, such kind of application is commonly seen, e.g., smart homes and elderly care systems. However, In AOCA applications, constraints for environment vary not only from person to person, but also from activity to activity. The openness of these constraints makes it difficult for developers to understand and specify them once and for all during the development. Furthermore, the environment of such application is also open and dynamic, so that it is also difficult to be developed once and for all. On the other hand, existing programming models for context-aware applications mainly attempt to deal with information from an overall level and develop once and for all. Few of them are qualified to support the development and the related running process of AOCA applications.For this new application form, this paper focuses on the construction of the sys-tem. Using "separation of concerns" as the guiding idea, this paper studies the tech-nologies of design and implementation for activity-oriented context-aware (AOCA) application systems from the perspectives of concept model, programming model, software development support, software runtime support system, etc. The innovative achievements are as follows.● An activity-oriented context (AOC) model is proposed. Based on this model, this paper provides the software model and the programming model for activity-oriented context-aware applications. In this approach, a context, which is dy-namic and local, is organized around a specific activity at runtime. The software model is composed of an environment infrastructure and constraints of applica-tions. This model reflects the idea of "separation of concerns". The proposed programming model is characterized by its light-weight and incremental nature, which caters to the openness and personalization of AOCA applications.● An AOCA applications development platform supporting above model is de-signed and implemented. This platform supports the independent and incremen-tal development of environment infrastructure and constraints related to activi-ties. The development of environment infrastructure is supported by a graphi-cal development tool; constraints are described by a domain-specific language AOCL. This platform also provides a whole AOCA application programming interface (API) for application developers.● A light-weight, pluggable runtime support platform for AOCA applications is designed and implemented. This platform supports the running of the artifacts developed by the proposed approach. Directed by the AOC concept model, the platform generates an unique context for each activity at its specific runtime. Proactive context managers are launched to manage such context. The managers check whether the constraints for environment are satisfied and provide services for the users proactively.● A formalization method of AOCA applications based on Ambient Calculus/Am-bient Logic is given in order to enhance the reliability of such applications. This method formalizes AOCA applications with Ambient Calculus and gives a for-mal specification of system-level and application-level consistency constraints with Ambient Logic. Designers and developers of AOCA applications are able to use the formal tools and specification method to formalize AOCA applica-tions in each development and runtime steps in order to detect faults in the early phases.