Yasuhide Mori

Memory-based architecture for distributed WWW caching proxy

Abstract In networks with heavy WWW traffic, the disk I O performance can become a bottleneck for caching proxies. To solve this problem, we propose a memory-based architecture for WWW caching proxies. The features of the proposed architecture are (1) a cache contents control that retrieves only frequently accessed WWW pages, and (2) an automatic distribution mechanism that enables efficient cache space sharing among multiple caching proxies. A statistical analysis shows that our approach reduces the required cache space. It consumes only 1 10 the cache space of current typical proxies while retaining the same cache hit rate. The reduced cache space enables the use of fast DRAMs in the caching proxies, and solves the disk I O problem.

Visualization of Information Spaces to Retrieve and Browse Image Data

We have developed a user interface for similarity-based image retrieval, where the distribution of retrieved data in a high-dimensional feature space is represented as a dynamical scatter diagram of thumbnail images in a 3-dimensional visualization space and similarities between data are represented as sizes in the 3-dimensional space. Coordinate systems in the visualization space are obtained by statistical calculations on the distribution of feature vectors of retrieved images. Our system provides some different transformations from a high-dimensional feature space to a 3-dimensional space that give different coordinate systems to the visualization space. By changing the coordinates automatically at some intervals, a spatial-temporal pattern of the distribution of images is generated. Furthermore a hierarchical coordinate system that consists of some local coordinate systems based on key images can be defined in the visualization space. These methods can represent a large number of retrieved results in a way that users can grasp intuitively.