Wireless networking technology is evolving but is facing problems of limited network bandwidth, high error rates, poor security,etc. New designs in mobile applications are needed to overcome these problems in mobile computing. Dynamic application partitioning is a potentially useful technique for developing new mobile applications. This thesis presents a case study of an object-oriented mobile e-mail browser, M-Mail, built using the Mentat system, with the mail folders modeled as Mentat objects. This application can be partitioned dynamically according to the wireless network conditions by placing the distributed objects at a mobile client or a proxy server. The thesis further describes a dynamic application partitioning scheme which determines when and how the application should be partitioned. The scheme mainly looks at the following factors: network bandwidth, error rate, latency as well as the size of the mobile objects and the costs of object method invocations. This scheme is implemented inside the Mentat system to provide transparency to the application developers and users. We execute M-Mail within the emulated wireless testbed at the Mobile Computing Group of the UniversityofWaterloo and the experimental results are presented. These experiments confirm that the dynamic partitioning scheme performs the best in low-bandwidth environment and achieves the best results for large folder objects. This scheme provides the mobile applications with better adaptability under the wireless environment than the static schemes of placing all the objects on one host. iv Acknowledgement Thanks to the everlasting God. Iwould like to thank my supervisor, Dr. Thomas Kunz, for his continuous guidance and suggestions on my research. I am grateful to Professor JohnnyWong and Pr...

Many contemporary inter-networked information systems simply co-exist and act in isolation. The component systems are typically heterogeneous since they have been developed under different data modeling formalisms and platforms. Yet, there is an ever increasing demand to create a unified information system in which users have efficient access to distributed information resources. In this paper, we present a architectural framework that can assist in building such aggregates of information systems. Key features of this framework find their origin in environments proposed by various standardization groups. 1 Introduction To function effectively, large organizations have to handle large volumes of information. To this end, automated information servers have been deployed at an ever increasing rate as the most effective way of dealing with this task. Companies have developed over time independent information systems for production, personnel, sales, marketing, research, and development. ...