source: other-projects/nightly-tasks/diffcol/trunk/model-collect/Word-PDF-Basic/archives/HASH019c.dir/doc.xml@ 29404

Last change on this file since 29404 was 29404, checked in by ak19, 6 years ago

Trying to rebuild the Word-PDF-Basic collection with unique dc.Title metadata for docs with identical final names and with the 2nd browsing classifier sorted on dc.Title, in order to produce a consistent order for browse classifier children (files under browsing classifiers). This is necessary for perl 5.18/5.17 and later, since they randomise the order of children of unsorted classifiers and for those children with identical filenames

File size: 41.0 KB
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53&lt;A name=1&gt;&lt;/a&gt;&lt;b&gt;Applications for Bibliometric Research&lt;/b&gt;&lt;br&gt;
54&lt;b&gt;in the Emerging Digital Libraries&lt;/b&gt;&lt;br&gt;
55Sally Jo Cunningham&lt;br&gt;
56Department of Computer Science&lt;br&gt;
57University of Waikato&lt;br&gt;
58Hamilton, New Zealand&lt;br&gt;
60&lt;b&gt;Abstract:&lt;/b&gt; Large numbers of research documents have recently become available on&lt;br&gt;
61the Internet through “digital libraries”, and these collections are seeing high levels of&lt;br&gt;
62use by their related research communities. A secondary use for these document&lt;br&gt;
63repositories and indexes is as a platform for bibliometric research. We examine the&lt;br&gt;
64extent to which the new digital libraries support conventional bibliometric analysis, and&lt;br&gt;
65discuss shortcomings in their current forms. Interestingly, these electronic text&lt;br&gt;
66archives also provide opportunities for new types of studies: generally the full text of&lt;br&gt;
67documents are available for analysis, giving a finer grain of insight than abstract-only&lt;br&gt;
68online databases; these repositories often contain technical reports or pre-prints, the&lt;br&gt;
69“grey literature” that has been previously unavailable for analysis; and document&lt;br&gt;
70“usage” can be measured directly by recording user accesses, rather than studied&lt;br&gt;
71indirectly through document references.&lt;br&gt;
72&lt;b&gt;1. Introduction&lt;/b&gt;&lt;br&gt;
73In recent years a number of &amp;quot;digital libraries&amp;quot; have become available through the&lt;br&gt;
74Internet. While the technology promises in the future to support large, heterogenous&lt;br&gt;
75collections, at present the most widely used of the academically-focussed digital&lt;br&gt;
76libraries are generally repositories of one or two types of document (typically technical&lt;br&gt;
77reports, journal articles, pre-prints, or conference proceedings), grouped by discipline.&lt;br&gt;
79&lt;A name=2&gt;&lt;/a&gt;A distinguishing characteristic of these digital libraries is that the full text of documents&lt;br&gt;
80are often available for retrieval, as well as bibliographic records.The sciences are&lt;br&gt;
81represented much more heavily in the present crop of digital libraries than the social&lt;br&gt;
82sciences, arts, or humanities. They are maintained by professional societies,&lt;br&gt;
83universities, research laboratories, and even private individuals. Access is generally&lt;br&gt;
84free, both to search and to download documents.&lt;br&gt;
85The emergence of these subject-specific digital libraries is particularly important&lt;br&gt;
86given the pattern of access to materials presently employed by research scientists.&lt;br&gt;
87Informal exchanges of preprints, reprints, and photocopies of papers passed on by&lt;br&gt;
88colleagues currently are major venues for the transmission of scientific information&lt;br&gt;
89between researchers in the sciences. In one study, the dependence on these sources&lt;br&gt;
90ranges from 12% (for chemistry) to 39% (for mathematics) of all papers cited in&lt;br&gt;
91researchers' own publications [11]. A qualitative study of study of how computer&lt;br&gt;
92scientists locate and retrieve documents (computing is one of the domains considered&lt;br&gt;
93later in this paper) indicates that for that field, technical reports and research documents&lt;br&gt;
94found in various locations on the Internet are a preferred source of information [6].&lt;br&gt;
95Many of the digital library systems discussed in this paper are repositories for just this&lt;br&gt;
96type of literature. The documents tend to be of high quality: primarily technical&lt;br&gt;
97reports or working papers from research institutions (both academic and commercial),&lt;br&gt;
98as well as advance copies of work accepted for publication in conventional paper&lt;br&gt;
99journals. Moreover, these digital libraries are also coming to include refereed work&lt;br&gt;
100published digitally (in electronic journals). Anecdotal evidence suggests that in their&lt;br&gt;
101fields, these digital libraries are coming to be the resource of choice for locating cutting&lt;br&gt;
102edge work.&lt;br&gt;
103For specialized subjects such as high energy physics, this dependence on&lt;br&gt;
104informal or extra-library dissemination can be much higher. Ginsparg ([9], [10])&lt;br&gt;
105reports that fields in physics have traditionally relied heavily on preprint exchanges, and&lt;br&gt;
106the digital repositories of physics preprints begun in 1991 (the PHYSICS E-PRINT&lt;br&gt;
107ARCHIVES) have to a large extent supplanted conventional publishing and physical&lt;br&gt;
109&lt;A name=3&gt;&lt;/a&gt;paper mailing of technical reports. By providing ready access to information sources&lt;br&gt;
110that are already preferentially utilized by scientists, the digital libraries show potential to&lt;br&gt;
111increase access to information that until recently was expensive or difficult to acquire in&lt;br&gt;
112paper form. Indeed, in some fields (most notably physics) this process has already&lt;br&gt;
113begun, as researchers in less developed countries report access to ongoing research&lt;br&gt;
114through the Internet repositories that their local libraries could not afford to acquire&lt;br&gt;
115through conventional journal subscriptions ([9], [10]).&lt;br&gt;
116The primary use for new bibliographic resources is, of course, for the contents&lt;br&gt;
117of the documents involved. A secondary use for emerging resources is as a basis for&lt;br&gt;
118bibliometric analysis of the subject field. With the conventionally published scientific&lt;br&gt;
119literature, the sheer difficulty of accumulating statistics discouraged bibliometric&lt;br&gt;
120research until the advent of large bibliographic databases in the 1960's. Computerized&lt;br&gt;
121bibliographic databases sparked a significant increase in the number of large-scale&lt;br&gt;
122bibliographic studies, as significant portions of the collection and analysis of data could&lt;br&gt;
123be automated ([12], [13]). The availability of CD-ROM versions of bibliographic&lt;br&gt;
124databases has been of particular importance, since they provide a cheaper alternative to&lt;br&gt;
125the online commercial databases [3].&lt;br&gt;
126These computerized bibliographic resources have drawbacks, however. The&lt;br&gt;
127greatest is that the full text of documents are rarely available, and even abstracts are not&lt;br&gt;
128always present. This obviously limits the types of bibliometric research that can be&lt;br&gt;
129conducted &lt;i&gt;solely&lt;/i&gt; through these databases. In addition, these databases are generally&lt;br&gt;
130limited to formally published documents (those appearing in selected books, journals,&lt;br&gt;
131and conference proceedings). The &amp;quot;grey literature&amp;quot; of technical reports, pre-prints, and&lt;br&gt;
132other works not formally published are largely ignored, and it is this absence of easy&lt;br&gt;
133access to these documents that has hampered the analysis of these important forms of&lt;br&gt;
134scientific communication.&lt;br&gt;
135The digital libraries currently in existence complement the online and CD-ROM&lt;br&gt;
136bibliographic databases. They are best suited for examinations of the &amp;quot;physical&amp;quot;&lt;br&gt;
137characteristics of documents (for example, document length), analysis based on&lt;br&gt;
139&lt;A name=4&gt;&lt;/a&gt;bibliographic information that can be automatically extracted from the document text or&lt;br&gt;
140the sometimes unevenly formatted bibliographic records (such as obsolescence&lt;br&gt;
141studies), and usage studies (geographic or institutional origin of users, date/time of&lt;br&gt;
142access, individual patterns of document retrieval, etc.). Because references are present&lt;br&gt;
143in the document file but not identified by field, co-citation and bibliographic coupling&lt;br&gt;
144research is not well-supported, and conducting these studies requires considerable&lt;br&gt;
145effort on the part of the researcher.&lt;br&gt;
146The variety of bibliographic repositories in the available digital libraries in itself&lt;br&gt;
147has great potential in conducting bibliometric research. Sigogneau et al [15] present a&lt;br&gt;
148case study illustrating the ways in which the strengths of different databases can be&lt;br&gt;
149played off each other; they conduct a fine-grained analysis of the emergence of research&lt;br&gt;
150fronts in molecular and cellular biology, and demonstrate that the observations gleaned&lt;br&gt;
151from two complementary bibliographic databases provide greater insight into their&lt;br&gt;
152problem. Similarly, it appears that the types of bibliographic data that can be gleaned&lt;br&gt;
153from the relatively unstructured digital libraries can be profitably combined with data&lt;br&gt;
154from online databases, CD-ROMS, and other more conventional bibliographic&lt;br&gt;
156This paper is organized as follows: Section 2 discusses the types of indexing&lt;br&gt;
157and searching available with current digital libraries; Section 3 gives examples of&lt;br&gt;
158conventional bibliometric techniques applied to Internet-accessible archives; Section 4&lt;br&gt;
159discusses opportunities to directly measure usage of documents and to detect&lt;br&gt;
160information-seeking patterns in researchers; and Section 5 presents our conclusions.&lt;br&gt;
161&lt;b&gt;2. Indexing and searching in current digital libraries&lt;/b&gt;&lt;br&gt;
162At present, the types of indexing fields for most academically-oriented digital&lt;br&gt;
163library systems are limited. Many schemes index on user-supplied document&lt;br&gt;
164descriptions, abstracts, or similar document surrogates (for example, the PHYSICS E-&lt;br&gt;
165PRINT ARCHIVE [10], a collection of physics pre-prints and technical reports). As will&lt;br&gt;
167&lt;A name=5&gt;&lt;/a&gt;be discussed below, the quality of this user-provided data can be highly variable, and&lt;br&gt;
168may unfavorably impact the usefulness of the index for searching. Alternatively, a&lt;br&gt;
169designated site librarian may maintain a catalog (eg, the WATERS [14] system, now&lt;br&gt;
170subsumed by NCSTRL (, both primarily collections of&lt;br&gt;
171computer science technical reports); in this case the quality of the bibliographic&lt;br&gt;
172information may be expedited to be higher, but fewer sites will be likely to support&lt;br&gt;
173such a librarian and therefore fewer documents are likely to be included in the digital&lt;br&gt;
174library. In a “harvesting” system such as the computer science technical report&lt;br&gt;
175collections supported by HARVEST [2] or the NEW ZEALAND DIGITAL LIBRARY&lt;br&gt;
176computer science technical report collection ([16], [17]), documents are indexed from&lt;br&gt;
177passive repositories (that may not even be aware that their documents are being&lt;br&gt;
178included in the digital library). Harvesting systems therefore cannot rely on the&lt;br&gt;
179presence of bibliographic data of any sort.&lt;br&gt;
180Because of the relative paucity of high-quality bibliographic data available to&lt;br&gt;
181many of the current academically- or research-focussed digital library collections, their&lt;br&gt;
182search interfaces tend to be more primitive than those ordinarily found in online&lt;br&gt;
183bibliographic databases or library catalogs. Systems such as NCSTRL can support&lt;br&gt;
184author, title, and subject searching, but this more sophisticated search functionality&lt;br&gt;
185comes at the expense of requiring participating repositories to use specific software. As&lt;br&gt;
186a consequence, these latter systems may provide access to a small number of sites than&lt;br&gt;
187harvesting systems. Harvesters may access a broader range of providers, but at the&lt;br&gt;
188penalty of being limited to unfielded, keyword searches over the raw text of the&lt;br&gt;
189document or document surrogate.&lt;br&gt;
190Specifically, the indexing in existing digital libraries has a variety of shortcomings for&lt;br&gt;
191bibliometric applications:&lt;br&gt;
193&lt;i&gt;lack of fielded indexing:&lt;/i&gt; As noted above, some large and widely used digital&lt;br&gt;
194libraries (such as the computer science technical report collection of the NEW&lt;br&gt;
195ZEALAND DIGITAL LIBRARY) may lack formal cataloging entirely, and rely on&lt;br&gt;
197&lt;A name=6&gt;&lt;/a&gt;keyword searching over the raw document text. Obviously this makes field-&lt;br&gt;
198dependent analysis more difficult (for example, locating documents produced by&lt;br&gt;
199specific authors), and in the worst case my require a manual examination of all&lt;br&gt;
200files in the collection in order to reliably identify a desired document subset.&lt;br&gt;
201However, keyword search techniques that approximate fielded searching results&lt;br&gt;
202may suffice: for example in the NEW ZEALAND DIGITAL LIBRARY computer&lt;br&gt;
203science technical report collection, limiting the keyword search for “Johnson”&lt;br&gt;
204to a search of first pages only is likely to retrieve documents written by Johnson&lt;br&gt;
205(since for the majority of computer science technical reports, the first page&lt;br&gt;
206contains little more than author, title, date, and institution details).&lt;br&gt;
207A more principled approach to extracting bibliographic information is embodied&lt;br&gt;
208in the CiteSeer tool [1]. This software parses raw, unfielded academic&lt;br&gt;
209documents and attempts to identify such indexing information as author, title,&lt;br&gt;
210reference list, etc. Obviously such a tool cannot attain 100% accuracy over a&lt;br&gt;
211heterogenous document collection, but in practice it appears useful in that it can&lt;br&gt;
212make a good first pass in processing a set of documents, providing an initial set&lt;br&gt;
213of parsed documents for analysis. The remaining (presumably much smaller) set&lt;br&gt;
214of unparsable documents can then be dealt with manually.&lt;br&gt;
216&lt;i&gt;lack of consistency in field formatting:&lt;/i&gt; Current digital libraries usually acquire&lt;br&gt;
217bibliographic information from either the authors of submitted articles or&lt;br&gt;
218automatic extraction routines (retrieving bibliographic details from catalog files&lt;br&gt;
219that may or may not be in a given document site, and that may or may not be in&lt;br&gt;
220an easily parsable form). Neither of these methods produce records with&lt;br&gt;
221standard formatting, which causes problems with automated bibliometric&lt;br&gt;
222analysis. Consider the following examples selected from entries in the hep-th&lt;br&gt;
223(high energy physics) collection of the PHYSICS E-PRINT ARCHIVES:&lt;br&gt;
225&lt;A name=7&gt;&lt;/a&gt;(i)&lt;br&gt;
226Authors: A. Yu. Alekseev, V. Schomerus&lt;br&gt;
228Authors: Adel Bilal and Ian. I. Kogan&lt;br&gt;
230Authors: Paul S. Aspinwall and David R. Morrison (with an appendix &lt;br&gt;
231by Mark Gross)&lt;br&gt;
233Authors: A. H. Chamseddine and Herbi Dreiner (ETH-Zurich)&lt;br&gt;
234In this case, typical for existing digital libraries, there is no standardized format&lt;br&gt;
235for authors' names (here, appearing with full names, initials plus last name, and&lt;br&gt;
236a mixture of the two); no standard convention for separating author names&lt;br&gt;
237(here, either a comma or &amp;quot;and&amp;quot; are used); and parenthetical information can&lt;br&gt;
238include a variety of information such as the name of an associate author or the&lt;br&gt;
239institutional affiliations of an author. Manual processing or specially crafted&lt;br&gt;
240software would be required to reformat these fields for analysis.&lt;br&gt;
242&lt;i&gt;duplicate entries: &lt;/i&gt; Digital libraries that draw documents from a variety of sources&lt;br&gt;
243may inadvertently contain duplicate items. Unfortunately, the irregular&lt;br&gt;
244formatting of the bibliographic information makes it difficult to automatically&lt;br&gt;
245detect these duplicates.&lt;br&gt;
247&lt;i&gt;implicit field tagging:&lt;/i&gt; In some repositories, items are not explicitly tagged with&lt;br&gt;
248certain types of information – most commonly the document's date of&lt;br&gt;
249publication or production. Instead, the date is implicit in the document's title&lt;br&gt;
250(eg, its numeration in a technical report series) or in the location of the document&lt;br&gt;
251in the file structure of the repository (eg, separate directories exist for each&lt;br&gt;
252year). A second common piece of implicit data is the authors’ institutional&lt;br&gt;
253affiliations. This may be contained in the document itself (typically on a cover&lt;br&gt;
254page), or may be implicit in the document’s location (for example, a&lt;br&gt;
255corporation’s technical reports are stored in its ftp repository). Again, in these&lt;br&gt;
257&lt;A name=8&gt;&lt;/a&gt;cases special processing is required to append this field information to a&lt;br&gt;
258document record for bibliometric analysis. &lt;br&gt;
260&lt;i&gt;extraction of document text:&lt;/i&gt; Few of the documents stored in the research-&lt;br&gt;
261oriented digital libraries discussed in this paper are straight ascii text; instead,&lt;br&gt;
262documents may appear in a variety of file formats, such as LaTeX, PostScript,&lt;br&gt;
263PDF, etc. If the contents of the documents are to be automatically processed&lt;br&gt;
264(for example, to count the words in a document, or to extract reference&lt;br&gt;
265publication dates for an obsolescence study), then the text must be extracted.&lt;br&gt;
266Utilities are available to convert most common document formats to ascii.&lt;br&gt;
267It is likely that many of these problems will be addressed as the Internet-based&lt;br&gt;
268document indexing systems mature. Even minor changes can greatly increase the&lt;br&gt;
269useability of a bibliographic database for bibliometric research. For example, the&lt;br&gt;
270addition of an explicit date tag to many online databases in 1975 sparked new&lt;br&gt;
271applications in time series research [3].&lt;br&gt;
272&lt;b&gt;3. Opportunities for applications of bibliometric techniques&lt;/b&gt;&lt;br&gt;
273One type of bibliometric research concentrates on quantifying fundamental,&lt;br&gt;
274structural details about a subject literature: how many items are published, how many&lt;br&gt;
275authors are publishing, over what time period documents are likely to be used, etc.&lt;br&gt;
276More complex studies analyze the relationships between documents, such as how&lt;br&gt;
277documents cluster into subjects. The following examples give a flavour of the&lt;br&gt;
278bibliometric research that is possible using the emerging digital libraries:&lt;br&gt;
279&lt;i&gt;examining the “physical” characteristics of archived documents&lt;/i&gt;&lt;br&gt;
280One relatively straightforward type of bibliometric study characterizes the&lt;br&gt;
281formats of different literatures. For example, Figure 1 presents a the range of the size&lt;br&gt;
283&lt;A name=9&gt;&lt;/a&gt;of computer science technical reports as measured by their length in pages. Of the&lt;br&gt;
28445,720 documents in the CSTR collection as of April 1998, nearly 1600 did not contain&lt;br&gt;
285page divisions in their files (and hence are excluded from analysis). Note that the&lt;br&gt;
286number of pages in the shorter documents (&amp;lt;50 pages) falls into an approximately&lt;br&gt;
287normal distribution (slightly skewed to the left), while presumably the longer&lt;br&gt;
288documents represent Masters’ and Doctoral theses. A surprising number of documents&lt;br&gt;
289are very short (between one and 5 pages); these may represent the type of condensed&lt;br&gt;
290results frequently found in the “technical notes”, “short papers”, and “poster sessions”&lt;br&gt;
291of computing conferences and journals. The average number of pages per document,&lt;br&gt;
29227.5, appears to be slightly longer than the common upper bound for a computing&lt;br&gt;
293journal article, although this observation must be confirmed by a similar study of the&lt;br&gt;
294lengths of formally published computing articles.&lt;br&gt;
295This type of analysis is of particular interest for technical reports, since they&lt;br&gt;
296have not been studied in the same detail as formally published papers. A comparison of&lt;br&gt;
297the physical characteristics of the formal and informal literature could provide&lt;br&gt;
298supporting evidence for common beliefs about the relationship between the two types&lt;br&gt;
299of documents. For example, do publishing constraints force journal and proceedings&lt;br&gt;
300articles to be shorter than technical reports, and therefore presumably omit technical&lt;br&gt;
301details of findings? Do technical reports contain more/less extensive reference sections?&lt;br&gt;
302If reference sections of technical reports are longer than those of published articles, then&lt;br&gt;
303citation links are being ommitted in published works; if technical reports contain fewer&lt;br&gt;
304references, then this may confirm earlier indications that computer scientists tend to&lt;br&gt;
305“research first” and do literature surveys later [6].&lt;br&gt;
306Figure 1. Range of sizes of CS technical reports, measured by number of pages&lt;br&gt;
307&lt;i&gt;obsolescence studies.&lt;/i&gt;&lt;br&gt;
308A document is considered obsolete when it is no longer referenced by the&lt;br&gt;
309current literature. Typically, documents receive their greatest number and frequency of&lt;br&gt;
311&lt;A name=10&gt;&lt;/a&gt;citations immediately after publication, and the frequency of citation falls rapidly as time&lt;br&gt;
312passes. One technique for estimating the obsolescence rate of a body of literature– the&lt;br&gt;
313&lt;i&gt;synchronous&lt;/i&gt; method – is to find the median date in the references of the documents.&lt;br&gt;
314This median date is subtracted from the year of publication for the documents, yielding&lt;br&gt;
315the &lt;i&gt;median citation age&lt;/i&gt;. As would be expected, this median varies between the&lt;br&gt;
316disciplines. Typically the social sciences and arts have a higher median citation age&lt;br&gt;
317than the “hard” sciences and engineering, indicating that documents obsolesce more&lt;br&gt;
318quickly for the latter fields.&lt;br&gt;
319As noted in Section 2, references are not generally explicitly tagged in existing&lt;br&gt;
320digital repositories. However, reference dates can usually be extracted from the&lt;br&gt;
321document text by first locating the reference section (usually delimited by a &amp;quot;references&amp;quot;&lt;br&gt;
322or &amp;quot;bibliography&amp;quot; section heading), and then extracting all numbers in the appropriate&lt;br&gt;
323ranges for dates for the field under study.&lt;br&gt;
324To illustrate this process, 188 technical reports were sampled from Internet-&lt;br&gt;
325accessible repositories1 and used as source documents for a synchronous obsolescence&lt;br&gt;
326study. Conveniently, the repositories chosen organize technical reports into sub-&lt;br&gt;
327directories by their date of publication. The reference dates for each technical report&lt;br&gt;
328were automatically extracted by software that scanned the document’s file for numbers&lt;br&gt;
329of the form 19XX, since previous studies indicate that few if any computing reports&lt;br&gt;
330reference documents published in previous centuries [5]. Table 1 presents the median&lt;br&gt;
331citation age calculated for these documents, broken down by repository and the year of&lt;br&gt;
332publication for the source documents from which the reference dates were extracted:&lt;br&gt;
333Table 1. Median citation ages for technical report repositories&lt;br&gt;
334The median citation age ranges between 2 and 4 years, which is consistent with&lt;br&gt;
335previous examinations of computing and information systems literature ([5], [4]).&lt;br&gt;
336When graphed, the distribution of reference dates show the exponential curve typically&lt;br&gt;
337found in obsolescence studies, including the final droop due to an “immediacy effect”&lt;br&gt;
339&lt;A name=11&gt;&lt;/a&gt;as fewer very new documents are available for citation [7]. These types of results&lt;br&gt;
340provide confirmation that references used in computer science technical reports (the pre-&lt;br&gt;
341eminent “grey literature” of the computing field) conforms to the same patterns as&lt;br&gt;
342references found in the formally published literature.&lt;br&gt;
343&lt;i&gt;co-citation and bibliographic coupling studies&lt;/i&gt;&lt;br&gt;
344The rate at which documents cite each other (co-citation) or cite the same&lt;br&gt;
345documents (bibliographic coupling) can be used to produce &amp;quot;maps&amp;quot; of a subject&lt;br&gt;
346literature. These techniques rely on analysis of the references of documents, and these&lt;br&gt;
347references must be in a common format. While digital libraries contain full text of&lt;br&gt;
348documents, their references are not standardized, and indeed are not even tagged as&lt;br&gt;
349such. To perform these studies the references must be manually extracted and&lt;br&gt;
350processed–a tedious process that is only worthwhile for documents (such as technical&lt;br&gt;
351reports) that are not included in existing citation databases such as the Science Citation&lt;br&gt;
352Index and Social Science Citation Index.&lt;br&gt;
353&lt;i&gt;detecting cycles or regularities in the rate of production of research&lt;/i&gt;&lt;br&gt;
354Analysis of trends in the production of technical reports can give indications&lt;br&gt;
355about working conditions that affect research; for example, is more research produced&lt;br&gt;
356over the summer, when the teaching load is lighter? or is research steadily produced&lt;br&gt;
357throughout the year?&lt;br&gt;
358Figure 2. Distribution of the number of documents submitted to hep-th, 1992-1994&lt;br&gt;
359Figures 2 and 3 present statistics on document accumulation in the hep-th (high&lt;br&gt;
360energy physics) e-print server, a part of the PHYSICS E-PRINT ARCHIVE. This system&lt;br&gt;
361is one of the oldest formal pre-print archives, and has become the primary means for&lt;br&gt;
362information dissemination in its field. Examination of these figures reveals several&lt;br&gt;
363trends. Clearly the absolute number of documents deposited in the repository has&lt;br&gt;
365&lt;A name=12&gt;&lt;/a&gt;tended to increase over the time period. For all three years, research production has its&lt;br&gt;
366lowest point in January and February, increases through May and June, then decreases&lt;br&gt;
367until August and September. At that point the rate of production steps up, reaching a&lt;br&gt;
368yearly peak in November and December. This pattern is less clear for 1992, which&lt;br&gt;
369might be expected as the archive was established in mid-1991.&lt;br&gt;
370Figure 3. Distribution of the percentage of documents submitted to hep-th, 1992-1994&lt;br&gt;
371&lt;b&gt;4. Analysis of usage data&lt;/b&gt;&lt;br&gt;
372The emerging Internet-based digital libraries will permit research on scientific&lt;br&gt;
373information collection and use at a much finer grain than is possible with current paper&lt;br&gt;
374libraries or online bibliographic databases. Current bibliometric or scientometric&lt;br&gt;
375research of this type must measure information use indirectly – for example, through&lt;br&gt;
376examination of the list of references appended to published articles. However, it is well&lt;br&gt;
377known that authors do not necessarily include in the reference list all documents that&lt;br&gt;
378could have been cited, and conversely that not all references listed may have been&lt;br&gt;
379actually “used” in performing the research; citation behavior can be affected by a&lt;br&gt;
380number of motivating factors (Garfield lists &lt;i&gt;15&lt;/i&gt; possible reasons in [8]).&lt;br&gt;
381Digital library transaction logs provide a powerful tool for direct analysis of&lt;br&gt;
382document “usage”: since digital libraries contain the actual document (rather than only a&lt;br&gt;
383document surrogate), the relative amount of “use” that a digital library’s clients make of&lt;br&gt;
384a given document sees can be estimated from the number of times the document file is&lt;br&gt;
385downloaded (and, presumably, the document is read). Note that file downloading is a&lt;br&gt;
386much stronger statement on the part of the user than, for example, having a&lt;br&gt;
387bibliographic record appear in the query result set for a conventional bibliographic&lt;br&gt;
388system; the user downloads only &lt;i&gt;after&lt;/i&gt; the document has been found potentially relevant&lt;br&gt;
389through examination of its document surrogate. Additionally, downloading is&lt;br&gt;
390frequently time-consuming and sometimes costly (depending on local pricing for&lt;br&gt;
392&lt;A name=13&gt;&lt;/a&gt;Internet access). Downloaded documents are therefore highly likely at least to be&lt;br&gt;
393scanned, if not read closely. The transaction logs for a digital library can provide a&lt;br&gt;
394global picture of the use of documents in the collection, since all user interactions with&lt;br&gt;
395the library can be automatically logged for analysis. By contrast, it is of course&lt;br&gt;
396impossible to track usage of print bibliographies, and very difficult to monitor usage of&lt;br&gt;
397bibliographic data available on CD-ROM across more than one or two sites.&lt;br&gt;
398Furthermore, analysis of search requests by geographic location, institution,&lt;br&gt;
399and sometimes even individual user are also possible. As an example, Table 2 presents&lt;br&gt;
400a portion of the summary of usage statistics (broken down by domain code) for queries&lt;br&gt;
401to the computer science technical collection of the NEW ZEALAND DIGITAL LIBRARY.&lt;br&gt;
402Examination of the data indicates that the heaviest use of the collection comes from&lt;br&gt;
403North America, Europe (particularly Germany and Finland), as well as the local New&lt;br&gt;
404Zealand community and nearby Australia. As expected for such a collection, a large&lt;br&gt;
405proportion of users are from educational (.edu) institutions; surprisingly, however, a&lt;br&gt;
406similar number of queries come from commercial (.com) organizations, indicating&lt;br&gt;
407perhaps that the documents are seeing use in commercial research and development&lt;br&gt;
409Table 2. Accesses to the NEW ZEALAND DIGITAL LIBRARY CS collection by Domain&lt;br&gt;Code&lt;br&gt;
410Of course, usage levels can also be further broken down by IP number&lt;br&gt;
411(indicating institutions), and systems requiring users to register may also be able to&lt;br&gt;
412analyze usage on an individual basis. Since the query strings themselves are also&lt;br&gt;
413recorded in the transaction logs, this domain/institution/individual activity could also be&lt;br&gt;
414linked to specific subjects through the query terms. Summaries of this type could be&lt;br&gt;
415invaluable for studies of geographic diffusion and distribution of research topics.&lt;br&gt;
416Transaction log analysis can also indicate time-related patterns in the&lt;br&gt;
417information seeking behavior of digital library users. As a sample of this type of&lt;br&gt;
418analysis, Paul Ginsparg notes a seven day periodicity in the number of search requests&lt;br&gt;
420&lt;A name=14&gt;&lt;/a&gt;made to the PHYSICS E-PRINT archives (Figure 4, reproduced from [9]). From this he&lt;br&gt;
421adduces that many physicists do not yet have weekend access to the Internet (an&lt;br&gt;
422alternative, slightly more cynical hypothesis is that even high energy theoretical&lt;br&gt;
423physicists take the weekend off).&lt;br&gt;
424Figure 4. Summary of search requests to the physics pre-print archives&lt;br&gt;
425&lt;b&gt;5. Conclusion&lt;/b&gt;&lt;br&gt;
426This study suggests opportunities for conducting bibliometric research on the&lt;br&gt;
427evolving digital libraries. These repositories are suitable platforms for conventional&lt;br&gt;
428bibliometric techniques (such as obsolescence studies, quantification of physical&lt;br&gt;
429characteristics of documents comprising a subject literature, time analysis, etc.). The&lt;br&gt;
430ability to directly monitor access to documents in digital libraries also enables&lt;br&gt;
431researchers to explicitly quantify document usage, as well as to implicitly measure&lt;br&gt;
432usage through citations. Additional facilities could aid in the performance of&lt;br&gt;
433bibliographic experiments, such as: improved tagging of document fields; provision of&lt;br&gt;
434utilities to strip out titles, authors, etc. from common document formats; and the ability&lt;br&gt;
435to easily eliminate duplicate entries from downloaded library subsets. Unfortunately,&lt;br&gt;
436the most useful of these additional facilities – those associated with a higher degree of&lt;br&gt;
437cataloging – run counter to the underlying philosophy of many digital libraries: to&lt;br&gt;
438avoid, if possible, manual processing and formal cataloging of documents. While&lt;br&gt;
439adherence to this principle can limit the accuracy of fielded searching (or indeed,&lt;br&gt;
440preclude it altogether), it can also avoid the cataloging bottleneck and permit digital&lt;br&gt;
441libraries to provide access to larger numbers of documents.&lt;br&gt;
442The digital libraries complement the information currently available through&lt;br&gt;
443paper, online, and CD-ROM bibliographic resources. While these latter databases&lt;br&gt;
444generally have the advantage of standardized formatting of bibliographic fields, the&lt;br&gt;
445digital libraries are freely accessible, often contain &amp;quot;grey literature&amp;quot; that is otherwise&lt;br&gt;
447&lt;A name=15&gt;&lt;/a&gt;unavailable for analysis, and generally make the full text of documents available. The&lt;br&gt;
448insights gained from analysis of digital libraries will add to the store of &amp;quot;information&lt;br&gt;
449about information&amp;quot; that we have gained from older types of bibliographic repositories.&lt;br&gt;
451[1] Bollacker, K.D., S. Lawrence, and C.L.Giles, CiteSeer: An Autonomous Web&lt;br&gt;
452Agent for Automatic Retrieval and Identification of Interesting Publications,&lt;br&gt;
453&lt;i&gt;Proceedings of the Second International Conference on Autonomous Agents&lt;/i&gt;&lt;br&gt;
454(Minneapolis/St. Paul, May 9-13), 1998.&lt;br&gt;
455[2] Bowman, C.M., P.B. Danzig, U. Manber, and M.F. Schwartz, Scalable Internet&lt;br&gt;
456resource discovery: Research problems and approaches, &lt;i&gt;Communications of&lt;/i&gt;&lt;br&gt;
457&lt;i&gt;the ACM 37(8)&lt;/i&gt; (1994) 98-107.&lt;br&gt;
458[3] Burton, Hilary D. , Use of a virtual information system for bibliometric analysis,&lt;br&gt;
459&lt;i&gt;Informaton Processing &amp;amp; Management 24(1)&lt;/i&gt; (1988) 39-44.&lt;br&gt;
460[4] Cunningham, S.J., An empirical investigation of the obsolescence rate for&lt;br&gt;
461information systems literature, &lt;i&gt;Library and Information Science&lt;/i&gt;&lt;br&gt;
462&lt;i&gt;Research&lt;/i&gt;., 1996,;br&gt;
463 [5] Cunningham, S.J., and D. Bocock, Obsolescence of computing literature.&lt;br&gt;
464&lt;i&gt;Scientometrics&lt;/i&gt; &lt;i&gt;34(2) &lt;/i&gt; (1995), pp. 255-262.&lt;br&gt;
465 [6] Cunningham, S.J. and Lynn Silipigni Connaway, Information searching&lt;br&gt;
466preferences and practices of computer science researchers, &lt;i&gt;Proceedings of&lt;/i&gt;&lt;br&gt;
467&lt;i&gt;OZCHI '96&lt;/i&gt; (1996) 294-299.&lt;br&gt;
468[7] de Solla Price, D.J., Citation measures of hard science, soft science, technology,&lt;br&gt;
469and nonscience. In: C.E. Nelson and D.K. Pollock (eds), &lt;i&gt;Communication&lt;/i&gt;&lt;br&gt;
470&lt;i&gt;among scientists and engineers&lt;/i&gt; (Heath Lexington, 1970).&lt;br&gt;
471[8] Garfield, E., &lt;i&gt;Citation Indexing: Its theory and application in Science, Technology&lt;/i&gt;&lt;br&gt;
472&lt;i&gt;and Humanities (&lt;/i&gt;Wiley, 1979).&lt;br&gt;
474&lt;A name=16&gt;&lt;/a&gt;[9] Ginsparg, P. After dinner remarks: 14 Oct ‘94 APS meeting at LANL, 1994&lt;br&gt;
475(&amp;lt;URL:;gt; ).&lt;br&gt;
476[10] Ginsparg, P., First steps towards electronic research communication, &lt;i&gt;Computers&lt;/i&gt;&lt;br&gt;
477&lt;i&gt;in Physics 8(4)&lt;/i&gt; (1994) 390-401. &lt;br&gt;
478[11] Hallmark, J., Scientists' access and retrieval of references cited in their recent&lt;br&gt;
479journal articles, &lt;i&gt; College and Research Libraries 55(3)&lt;/i&gt; (1994) 199-210.&lt;br&gt;
480[12] Hawkins, D.T. , Unconventional uses of on-line information retrieval systems:&lt;br&gt;
481on-line bibliometric studies, &lt;i&gt;Journal of the American Society for Information&lt;/i&gt;&lt;br&gt;
482&lt;i&gt;Science 28&lt;/i&gt; (1977) 13-18.&lt;br&gt;
483[13] McGhee, P.E. , P.R. Skinner, K. Roberto, N.J. Ridenour, and S.M. Larson,&lt;br&gt;
484Using online databases to study current research trends: an online bibliometric&lt;br&gt;
485study, &lt;i&gt;Library and Information Science Research 9&lt;/i&gt; (1987) 285-291.&lt;br&gt;
486[14] Maly, K., E.A. Fox, J.C. French, and A.L. Selman, Wide area technical report&lt;br&gt;
487server (&lt;i&gt;Technical Report , &lt;/i&gt; Dept. of Computer Science, Old Dominion&lt;br&gt;
488University, &lt;br&gt;
4891994. &lt;br&gt;
490Also &lt;br&gt;
491available &lt;br&gt;
492at &lt;br&gt;
493 &lt;br&gt;
494 &lt;br&gt;
496;gt; ).&lt;br&gt;
497[15] Sigogneau, M.J. , S. Bain, J.P. Courtial, and H. Feillet, Scientific innovation in&lt;br&gt;
498bibliographical databases: a comparative study of the Science Citation Index&lt;br&gt;
499and the Pascal database, &lt;i&gt;Scientometrics 22(1)&lt;/i&gt; (1991) 65-82.&lt;br&gt;
500[16] Witten, I.H., S.J. Cunningham, M. Vallabh, and T.C. Bell, A New Zealand&lt;br&gt;
501digital library for computer science research, &lt;i&gt;Proceedings of Digital Libraries&lt;/i&gt;&lt;br&gt;
502&lt;i&gt;'95&lt;/i&gt; (1995) 25-30.&lt;br&gt;
503[17] Witten, I.H., C. Nevill-Manning, and S.J. Cunningham, A public library based&lt;br&gt;
504on full-text retrieval, &lt;i&gt;Communications of the ACM&lt;/i&gt; 41(4), 1998, p. 71&lt;br&gt;
506&lt;A name=17&gt;&lt;/a&gt; &lt;br&gt;
5071Documents were randomly sampled from the DEC&lt;br&gt;
508(, Sony&lt;br&gt;
509(, and Ohio (ftp://archive.cis.ohio-&lt;br&gt; technical report repositories&lt;br&gt;
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