A study explores the way people organize information in support of projects ("teach a course", "plan a wedding", etc.). The folder structures to organize project information -especially electronic documents and other filesfrequently resembled a "divide and conquer" problem decomposition with subfolders corresponding to major components (subprojects) of the project. Folders were clearly more than simply a means to one end: Organizing for later retrieval. Folders were information in their own right -representing, for example, a person's evolving understanding of a project and its components. Unfortunately, folders are often "overloaded" with information. For example, folders sometimes included leading characters to force an ordering ("aa", "zz"). And folder hierarchies frequently reflected a tension between organizing information for current use vs. repeated re-use.

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A portable acoustic tracking system has been developed f o r t h e Navy to track underwater cons t r u c t i o n teams i n water d e p t h s t o 300 f t . The tracking system can be deployed and operated by t h e d i v e r s and i s intended for use in remote areas and for nearshore survey, maintenance, and c o n s t r u c t i o n work. A self-calibrating system provides a geo-