Center of Excellence in Space Data and Information Science, Year 9

This report summarizes the range of computer science related activities undertaken by CESDIS(Center of Excellence in Space Data and Information Sciences) for NASA in the twelve months from July 1, 1996 through June 30, 1997. These activities address issues related to accessing, processing, and analyzing data from space observing systems through collaborative efforts with university, industry, and NASA space and Earth scientists

Issues for bringing digital libraries into public use

In much the same way that the field of artificial intelligence produced a cult which fervently believed that computers would soon think like human beings, the existence of electronic books has resurrected the paperless society as a utopian vision to some, an apocalyptic horror to others. In this essay we have attempted to provide realistic notions of what digital libraries are likely to become if they are a popular success. E-books are capable of subsuming most of the media we use today and have the potential for added functionality by being interactive. The environmental impact of having millions more computers will be offset to some degree, perhaps even exceeded, by the fact that televisions, stereos, VCR's, CD players, newspapers, magazines, and books will become part of the computer system or be made redundant. On the whole, large-scale use of digital libraries is likely to be a winning proposition. Whether or not this comes to pass depends on the directions taken by today's researchers and software developers. By involving the public, the effort being put into digital libraries can be leveraged into something which is big enough to make a real change for the better. If digital libraries remain the exclusive property of government, universities, and large research firms, then large parts of the world will remain without digital libraries for years to come, just as they have remained without digital phone service for far too long. If software companies try to scuttle the project by patenting crucial algorithms and using proprietary data formats, all of us will suffer. Let us reverse the errors of the past and create a truly open digital library system

On Data Management in Pervasive Computing Environments

Abstract—This paper presents a framework to address new data management challenges introduced by data-intensive, pervasive computing environments. These challenges include a spatio-temporal variation of data and data source availability, lack of a global catalog and schema, and no guarantee of reconnection among peers due to the serendipitous nature of the environment. An important aspect of our solution is to treat devices as semiautonomous peers guided in their interactions by profiles and context. The profiles are grounded in a semantically rich language and represent information about users, devices, and data described in terms of “beliefs,” “desires, ” and “intentions. ” We present a prototype implementation of this framework over combined Bluetooth and Ad Hoc 802.11 networks and present experimental and simulation results that validate our approach and measure system performance. Index Terms—Mobile data management, pervasive computing environments, data and knowledge representation, profile-driven caching algorithm, profile driven data management, data-centric routing algorithm. æ

Virtual Telescopes in Education

Virtual Telescopes in Education is providing the services required to operate a virtual observatory comprising distributed telescopes, including an interactive, constraint-based scheduling service, data and resource archive, proposal preparation and review environment, and a VTIE Journal. A major goal of VTIE is to elicit from learners questions about the nature of celestial objects and the physical processes that give rise to the spectacular imagery that catches their imaginations. Generation of constrained science questions will assist learners in the science process. To achieve interoperability with other NSDL resources, our approach follows the Open Archives Initiative and the W3C Semantic Web activity

Online Data Compression in a Mass Storage File System

A Unix based mass storage file system which provides access to the stored data only through the ftp protocol has provided the incentive to examine the performance of inserting an online data compression algorithm at each client in order to increase the effective capacity of the storage system. Two online compression algorithms were tested, namely the Ziv-Lempel (gzip) and LZW (compress) algorithms, using both a sequential and a pipelined implementation. Their performance was compared based on their execution time and the compression ratio attained for different types of files. The results show that in addition to a significant increase of the effective storage capacity, network traffic is reduced and the effective size of the disk cache is also increased thereby increasing the number of hits. 1 Introduction Mass storage systems are used in research environments for storing data generated by scientific simulations and satelite observations in amounts on the order of terabytes. The cos..