Mobile computing is becoming more and more popular and
common. In the near future, people will be able to use mobile computers
(Laptops, palmtops, etc.) to do various computing tasks and to access the
Internet from anywhere and anytime at will. The development of wireless
facilities and mobile computers has made this goal possible, and some of the
mobile applications exist already. But the situation
is still far from ideal. There is still a lot of work to be
done to reach the goal. Compared with a wired network environment, a
mobile computing network has a lot of problems. A
wireless link has low bandwidth and is unstable. Mobile devices are resource
limited, like memory, storage, display area, power, etc. All these factors
cause problems for mobile applications. Mobile network users usually suffer
from long latencies and frequent disconnection, mobile applications suffers
from bad performance. In recent years, a lot of research have
been done to deal with these issues, to improve the mobile application
performance. The proposed techniques include caching, prefetching, compression,
etc.
The goal of this thesis is to study the techniques to improve client performance in client/server mobile computing systems, to identify which of the techniques are most promising and can be adapted to a tourist application (map viewing on small handheld devices, or other information like buses, menus, and theatre agendas, traffic and weather, etc.). We designed and implemented a mobile client/server application - a Mobile Map System. Based on our study on mobile computing techniques and the features of the mobile map application, we identified some caching and prefetching techniques and integrated them into our mobile map application. Through experiments, we studied the impact of these techniques to the performance of the application and concluded that the caching only method is a better solution to improve the performance of the mobile map application.