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Preserving long-term access to digital information resources is one of the key challenges facing libraries and information centers today. The University of North Texas (UNT) Libraries has entered into partnership agreements with federal and state agencies to ensure permanent storage and public access to a variety of government information sources. As digital resource preservation encompasses a wide variety of interrelated activities, the UNT Libraries are taking a phased approach to ensure the long-term access to its digital resources. Formulation of preservation policy and creation of preservation metadata for electronic files and digital collections are among the most important steps. This paper discusses the issues related to digital resources preservation and demonstrates the role of preservation metadata in facilitating the preservation activities in general. In particular, it describes the efforts being made by the UNT libraries to ensure the long-term access and preservation of various digital information resources.

Digital Library for Earth Science Education, DLESE / The community digital library has emerged as a recent evolution in the development of digital libraries. A community digital library is distinct through having a community of potential users define and guide the development of the library. In this article, we present how the geoscience community has worked to develop The Digital Library for Earth System Education (DLESE) in the light of recent work in the area of meta-design, the design of the design process. The development of DLESE is described utilizing a conceptual framework developed from the analysis of a variety of open source projects.

The Belgians Otlet en La Fontaine created the Universal Decimal Classification in order to collect and organize the world's knowledge. This happened in an age when information was almost exclusively made available by libraries. Since the internet, the quantity of information outside libraries is enormous and keeps growing every day. The internet is accessible to anybody, it is fundamentally unorganized and its content changes constantly. Collecting and organizing the world's knowledge seem to have become an impossible ambition. Perhaps it is even unnecessary, since search engines make information retrievable now. And why would we organize information if we can find it? So what will be the role of UDC and libraries in this internet environment? Libraries can still play a role as a major information provider, if they adapt fully to the expectations of a modern end user. The design and the functionalities of online catalogues should allow maximal accessibility, usability and active participation of the end user in the internet environment. Metadata, like UDC, should maximize the visibility of information, enrich it and invite the end user to assign metadata himself.

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There has been in recent years a surge of interest about new software products that make it possible for libraries to offer assistance to online users via chat. Such software offers far more interactivity than instant messaging programs and allow for a richer experience for both librarian and user. Surveys chat reference services around the globe and analyzes trends in the provision of this new mode of assistance. Also presents discussion of why chat reference service is gathering attention as well as its limitations and drawbacks.

The dissertation is a description of an analysis and a case study of an Optimization Stage for a Standard Cell oriented silicon compiler. Using the AHPL hardware description language, a complete representation hierarchy (functional, logic, and layout) is proposed for circuits defined at a Register Transfer level. The design of a new class of methods for layout analysis and optimization is based on this hierarchy. A layout evaluation method is based on the analysis of an activity graph derived from a circuit layout. The cost measure for such a graph is defined and used in evaluation of the necessary and sufficient conditions for design optimality (NSCDO). Iterations within the optimization process are controlled using a synthetic measure derived from these optimality conditions. A proposed layout optimization heuristic, derived from NSCDO, allows for better routing channel area utilization without compromising a circuit's timing performance. It is based on an analysis of the timing behavior modifications introduced by the various materials used as interconnectors resulting in an improvement of the load dependency of the output driving capabilities of cells. The dissertation contains an example of a quantitative analysis of a CMOS digital circuit. A system implementing some of the algorithms described above has been written in FORTRAN77.

The problems of noise removal, and simultaneous noise removal and deblurring of imagery are common to many areas of science. An approach which allows for the unified treatment of both problems involves modeling imagery as a sample of a random process. Various nonstationary image models are explored in this context. Attention is directed to identifying the model parameters from imagery which has been corrupted by noise and possibly blur, and the use of the model to form an optimal reconstruction of the image. Throughout the work, emphasis is placed on both theoretical development and practical considerations involved in achieving this reconstruction. The results indicate that the use of nonstationary image models offers considerable improvement over traditional techniques.