Multi-resolution cache management in digital virtual library

We envision a particular kind of digital libraries application, the application of user experience in walking through a large virtual environment, viewing virtual objects from different distances and angles. To provide a good performance of such applications, we need to address several research issues. First, we must be able to model virtual objects effectively. The recently developed multi-resolution object modeling techniques are capable of simplifying the object models and therefore reducing the time to render them. Second, with the limited bandwidth of the Internet, caching of suitable objects of high affinity will reduce the dependency on the network and thus, could reduce the response time. Third, the Internet often suffers from disconnection. A caching mechanism that allows objects to be cached with at least their minimum resolution will be useful to provide at least a coarse view of the objects to the viewer. In this paper, we propose a multi-resolution caching mechanism and investigate the effectiveness of the mechanism in supporting virtual walkthrough applications in the Internet environment. The caching mechanism allows virtual objects from a remote database server to be cached in the local storage of a client at various degrees of resolution. We also attempt to quantify the performance of the mechanism via simulated experiments.