Search

This paper describes a peer-to-peer (p2p) system (beacond) that is suitable for teaching important concepts in ubiquitous computing. The system exposes issues in peer location, p2p services, security and privacy issues. The system provided enough background to compliment class lectures and assisted students in designing their own course projects. Students continue to explore ideas exposed by beacond; some of these ideas are being further developed for publication in research conferences[1]. We present our experiences in using this framework for three different course offerings.

Medical images are captured in a 16-bit high-resolution grayscale format and are large, frequently reaching MBs per image and PBs for the archive. Regulatory compliance requirements make de-ploying new full image compression techniques difficult. Instead of forcing applications and end users to deal with the deployment complexity, we show that image data can be effectively and transparently compressed by the storage infrastructure. We analyzed our MICA compressor performance using five million publicly available medical images (> 2.2 TB) in three different image formats from eight sources. With 8KB blocks, we achieved 13% better compression, 10% better compression throughput and 782% better uncompression throughput than JPEG-LS. MICA also offered some compression for non-medical data that was incidentally stored in the same storage system.

Faunus addresses the challenge of specifying and managing complex collaboration sessions. Many entities from various administrative domains orchestrate such sessions. Faunus decouples the entities that specify the session from entities that activate and manage them. It restricts the operations to specific agents using capabilities. It unifies the specification and management operations through its naming system. Each Faunus name is persistent and globally unique. A collection of attributes are attached to each name. Together, they represent a collection of services that form a collaboration session. Anyone can create a name; the creator has full read and write privileges that can be delegated to others. With the proper capability, anyone can modify session attributes between an active and inactive state. Though the system is designed for Internet scale deployments, the security model for providing and revoking capabilities currently assumes an Intranet style deployment. We have incorporated Faunus into a DisplayCast system that originally used Zeroconf. We are incorporating Faunus into another project that will fully exercise the power of Faunus.