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Table 4. Access by Non-US Sites
Multimedia Use in ETDs
One of the main objectives of NDLTD is to promote student creativity through the use of diverse types of multimedia content in ETDs, while making students comfortable with the use of this technology to exploit richer modes of self-expression.
Table 5 indicates how much of this objective has been achieved in the VT-ETD collection, with a breakdown of the 8,056 multimedia files contained in a selection of 2,180 available ETDs. This illustrates both that authors are beginning to shift towards non-textual media and that some are moving away from the early single-file paradigm of digitization.
|Still image||BMP, DXF, GIF, JPG, TIFF|
|Video||AVI, MOV, MPG, QT|
|Text||PDF, HTML, TXT, DOC, XLS|
|Other||Macromedia, SGML, XML|
Table 5. Multimedia use in VT-ETD collection
In terms of copyright, a significant issue is whether to allow the electronic document to be viewed worldwide, on campus only, or not at all. The mixed case, which is a unique capability of electronic documents, occurs when some portions (e.g., particular chapters or multimedia files) have restricted access while others are more widely available. The majority of Virginia Tech students allow their documents to be viewable worldwide (see Figure 1) - but some initially choose not to grant worldwide access in order to protect their publication rights. To address this concern, there are ongoing discussions with publishers to help them understand the goals and benefits of NDLTD [NDLTD, 1999]. We are pleased to see a change in attitude by some publishers over the course of the project. The American Chemical Society developed a policy more favorable to NDLTD as a result of lengthy discussions and the American Physics Society has been receptive to issues concerning the Open Archives Initiative and NDLTD.
Figure 1. Student and committee choice for ETD availability from Virginia Tech
(2668 ETDs as of July 17, 2000).
In order to support many of the current and future research and service-related activities, work has begun to define standards that will enable more consistent exchange of information in an interoperable environment. Among the first of these projects is ETDMS - the Electronic Thesis and Dissertation Metadata Standard - and a related project for name authority control.
Electronic Thesis and Dissertation Metadata Standard (ETDMS)
ETDMS was developed in conjunction with the NDLTD, and has been refined over the course of the last year. The initial goal was to develop a single standard XML DTD for encoding the full text of an ETD. Among other things, an ETD encoded in XML could include rich metadata about the author and work that could easily be extracted for use in union databases and the like. During initial discussions it became clear that the methods used by different institutions to prepare and deal with theses and dissertations would make it all but impossible to agree on a single DTD for encoding the full text of an ETD. Many institutions were unwilling or unprepared to use XML to encode ETDs at all.
Thus, instead of an XML DTD for encoding the full text of an ETD, ETDMS emerged as a flexible set of guidelines for encoding and sharing very basic metadata regarding ETDs among institutions. Separate work continues in parallel on a suite of DTDs, building on a common framework, for full ETDs.
ETDMS is based on the Dublin Core Element Set [DCMI, 1999], but includes an additional element specific to metadata regarding theses and dissertations. Despite its name, ETDMS is designed to deal with metadata associated with both paper and electronic theses and dissertations. It also is designed to handle metadata in many languages, including metadata regarding a single work that has been recorded in different languages. The ETDMS standard [Atkins, et al., 2001] provides detailed guidelines on mapping information about an ETD to metadata elements.
ETDMS already is supported as an output format for the Open Archives interface to the Virginia Tech ETD collection. ETDMS will be accepted as an input format for the union catalog currently being developed in conjunction with VTLS [VTLS, 2001]. NDLTD strongly encourages use of ETDMS.
Each reference to an individual or institution in an ETDMS field should contain a string representing the name of the individual or institution as it appears in the work. In addition, these references also may contain a URI that points to an authoritative record for that individual or institution. Associating authority control with NDLTD seems particularly appropriate since universities know a great deal about those to whom they award degrees and since a thesis or dissertation often is the first significant publication of a student.
The NDLTD: Authority Linking Proposal [Young, 2001] identifies several goals for a Linked Authority File (LAF) system to support this requirement:
- LAF records should be freely created and shared among participants. While a central authority database is an option, the LAF design expects the database to be distributed to share cost. Individual participants or groups should be able to host a copy of the LAF database and share changes they make to local copies of LAF records with other hosts using the Open Archives Initiative (OAI) protocol [Lagoze and Van de Sompel, 2001]. The mechanism for keeping records in sync is described in the proposal.
- The URIs should be meaningful and useful to anyone outside NDLTDs domain. A benefit of using the OAI protocol is that individual LAF records will be accessible via an OAI GetRecord request (discussed in the second part of this article).
- The URIs should be persistent and current. This raises a number of challenges, such as duplicate resolution. By using PURLs [OCLC, 2001] in ETDMS records, the underlying OAI GetRecord URLs can be rearranged without affecting the ETDMS records that rely on them.
- The model should be scalable and applicable beyond NDLTD. The LAF model was designed to work entirely with open standards and open-source software.
The LAF design has other advantages over alternatives such as the Library of Congress Name Authority Database [Library of Congress, 2001]. Only the level of participation among decentralized participants limits the coverage of the collection. Because the records are based on XML, the content of LAF records can be as broad or narrow as needed. Finally, because they are distributed using the OAI protocol, multiple metadata formats can be supported.
Future of NDLTD
The statistics presented illustrate that the production and archiving of electronic theses and dissertations is fast becoming an accepted part of the normal operation of universities in the new electronic age. NDLTD is dedicated to supporting this trend with tools, standards, and services that empower individual institutions to set up and maintain their own collections of ETDs. At the same time NDLTD promotes the use of these ETDs through institutional websites as well as portal-type websites that aggregate the individual sites and create seamless views of the NDLTD collection.
Ongoing research and service-provision projects are addressing the problems of how to merge together the currently distributed and somewhat isolated collections hosted at each member institution. The second part of this article discusses some of these projects in detail, including development of the Union Catalog Portal based on VTLSs Virtua system and the myriad of research efforts investigating how to provide better services to researchers with specific information-seeking needs and behaviors.
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