The main goal of this thesis is to conceive and design a platform for context-aware services in a mobile-computing environment. In this chapter a conclusion is given based on the analysis performed followed by additional guidelines for future work.
7.1 Conclusion
This thesis is focusing on exploring the Context Toolkit, as a sample of a context-aware framework, detecting its strengths and weaknesses, identifying the possible enhancements and successively proposing a design of a new context aware framework.
From the analysis performed on the Context Toolkit, it can be concluded that it possesses a number of good design principles such as: reusability, distributed approach, resource discovery mechanism, storage of context data, automatic unsubscribing, context monitoring and feedback etc. However, weaknesses are present as well: the discoverer is a single point of failure, there is a need for clocks synchronization, there is no automatic restarting, there is lack of interoperability support, privacy and security are not yet implemented, there is no reasoning engine, and there is an absence of a conflict solving mechanism.
In this thesis, some of these issues were closely looked into and examined. For example, a quality of context mechanism is proposed for improving the quality of the application by making it more reliable and offering service adequate to the application developer’s or user’s demands. Also several proposals were suggested as a possible way of improving the resource discovery mechanism. Moreover, a matter that would need further focus is the interoperability, in particular making the context data and services provided from one platform available for discovery and usage by others as well. A mechanism has to be developed that will interface with different platforms and will reuse the context sources implemented with different frameworks by providing a common interface that everybody can interact with.
A prototype application has also been developed for the purpose of evaluating the Context Toolkit and obtaining hands-on experience of building a context-aware application. Each widget was easily developed, but integration of all the services has not been a seamless task, since the way they interact between each other has to be carefully established and implemented. Another difficulty was the testing; setting up all the involved context parameters on a joined timescale that matches the present, at times was found somewhat troublesome. Also, dealing with different technologies required studying all the sensors’ specifications and interfaces just to be able to extract the context info needed for the application.
Consequently, after gaining practical experience with developing a sample application and analyzing the Context Toolkit, a conceptual model of a context-aware platform was proposed. It defines the components necessary for building context-aware applications, and the interactions between them. The suggested design is general and should fulfill the demands of a number of application areas of the context-aware application development. It is a combination of several studied architectural designs. It comprises the widget paradigm, the blackboard model and complies with the networked services approach.
Some of the platforms reviewed totally lack important modules for building a complete context-aware application. Therefore, when designing the platform several aspects were taken into consideration such as: the necessity of quality of context handling, conflict resolution, reasoning engine and a privacy and security module.
Approaches such as user-centered design, prediction of user’s preferences and testing these assumptions are important for the design of the platform therefore an analyzer of the user behavior was also a component added in the proposed architecture.
Furthermore, a general flow of actions has been defined that presents the main idea of the system’s functioning.
Finally, the designed platform does not drastically defer from the other analyzed. Most of them follow the layered approach and have similar abilities because they are based on similar methodologies. What defers in the proposed model is the completeness. It covers the central points of concern that improve the performance and the overall quality of the developed applications.
7.2 Future work
Further work in this area encompasses several aspects, outlined as following:
The prototype was developed in order to get familiar with the Context Toolkit, its drawbacks, missing functionalities, sample design principles, software practices, technologies and examine the need for its future expansion. It has not been built in order to satisfy scalability issues and it was developed without the intention to go in real production. It serves only as a proof of concept. However, there are issues in its current implementation that can be further improved. The application could be expanded to support remote monitoring of several persons at a time, sending SMS messages to the elderly and his family members in case of an alerting situation and enriching the application with more context information in order to get more exact
information about the current situation. New services can also be offered: fall detection, abnormal heart rate state alarm, nutritional recommendations, fridge monitoring system (by tracking the items left inside the refrigerator and constructing the shopping list) etc.
Concerning the Context Toolkit, its future development can cover: complete implementation of the quality of context mechanism including a conflict resolution engine which will be standardized and will adapt on the information provided, extending the widget description with other parameters that describe it in greater details, introducing redundancy in the system and replicating the Discoverer component for achieving better reliability, and adding a module that will aid interoperability by making the context info more available to other frameworks.
Moreover, proposing solutions for the other weaknesses detected and their implementation can also be a topic for further work.
Last, the proposed context-aware framework in this thesis is general. It defines the architectural design principles and identifies the necessary components. Further work would include more detailed specification of the building elements and selection of the algorithms that some need to define. This should be followed with an implementation of the proposed solutions and sample application development which will serve for evaluation purposes.