共查询到20条相似文献，搜索用时 140 毫秒
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论高校文献课教学的发展规律 总被引：5，自引：0，他引：5
论高校文献课教学的发展规律朱育培Ａｂｓｔｒａｃｔ：Ｉｎｐｒｏｃｅｓｓｏｆｉｎｓｒｕｃｔｉｎｇｄｏｃｕｍｅｎｔａｔｉｏｎｃｏｕｒｓｅｉｎｃｏｌｌｅｇｅｓａｎｄｕｎｉｖｅｒｓｉｔｉｅｓ，ｔｈｅｉｎｆｏｒｍａｔｉｏｎｃｏｎｓｃｉｏｕｓｎｅｓｓｏｆｔｅａｃｈ... 相似文献
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图书馆员职业道德实践中的良心观 总被引：1，自引：0，他引：1
图书馆员职业道德实践中的良心观蔡金钟Ａｂｓｔｒａｃｔ：Ｔｈｅｃｏｎｃｓｃｉｅｎｃｅｃｏｎｃｅｐｔｐｌａｙｓａｎｉｍｐｏｒｔａｎｔｒｏｌｅｆｏｒｌｉｂｒａｒｉａｎｓｉｎｔｈｅｐｒｏｆｅｓｓｉｏｎａｌｅｔｈｉｃｓｐｒａｃｔｉｃｅｓ．Ｉｔｃｏｎ－ｔａｉｎｓ... 相似文献
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树立信息观念 开创文献情报工作新局面 总被引：4，自引：0，他引：4
树立信息观念开创文献情报工作新局面白国应Ａｂｓｔｒａｃｔ：Ｔｈｅｂａｓｉｃｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｔｈｅｓｅｎｓｅｏｆｉｎｆｏｒｍａｔｉｏｎａｒｅｐｒａｃｔｉｃａｌｎｅｓｓ，ｋｎｏｗｌｅｄｇｅａｂｌｅｎｅｓｓ，ｔｒａｎｓｍｉｓｓｉｂｉｌｉｔ... 相似文献
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论文献的科学评价功能 总被引：6，自引：0，他引：6
论文献的科学评价功能娄策群ＡＢＳＴＲＡＣＴＳｉｎｃｅｐｕｂｌｉｃａｔｉｏｎｓａｒｅｒｅｓｕｌｔｓｏｆｒｅｓｅａｒｃｈａｎｄｔｈｅｉｒｍｅ－ｄｉａ，ｔｈｅｙｒｅｆｌｅｃｔｖａｒｉｏｕｓａｓｐｅｃｔｓｏｆｓｃｉｅｎｃｅａｎｄｔｈｕｓｈａｖｅｔｈｅｆｕｎｃ... 相似文献
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情报科学技术的新发展 总被引：1，自引：0，他引：1
情报科学技术的新发展谢新洲Ａｂｓｔｒａｃｔ：Ｉｎｆｏｒｍａｔｉｏｎｓｃｉｅｎｃｅａｎｄｔｅｃｈｎｏｌｏｇｙｈａｓｉｎｔｈｅｒｅｃｅｎｔｙｅａｒｓｍａｋｅａｖｅｒｙｆａｓｔｐｒｏｇｒｅｓｓ，Ｔｈｅｐａｐｅｒｉｎｔｒｏｄｕｃｅｓｎｅｗｐｒｏｇｒｅｓｓｅｓ... 相似文献
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对新形势下学术活动的思考王启宇Ａｂｓｔｒａｃｔ：Ｌｉｂｒａｒｙａｃａｄｅｍｉｃａｃｔｉｖｉｔｉｅｓｕｎｄｅｒｔｈｅｎｅｗｓｉｔｕａｔｉｏｎｈａｖｅｗｉｔｎｅｓｓｅｄｎｅｗｔｒｅｎｄｓ．Ｓｏｃｉｅｔｉｅｓｏｆｌｉｂｒａｒｙｓｃｉｅｎｃｅｓｈｏｕｌｄｂｏ... 相似文献
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Keshra Sangwal 《Journal of Informetrics》2013,7(2):487-504
The distributions of citations L, two- (IF2) and five-year impact factors (IF5), and citation half-lives λ of journals published in different selected countries are analyzed using Langmuir-type relation: yn = y0 {1 ? αKn/(1 + Kn)}, where yn denotes Ln, IF2n or IF5n of n-ranked journal, y0 is the value of yn when journal rank n = 0, α is an empirical effectiveness parameter, and K is the Langmuir constant. It was found that: (1) the general features of the distribution of Ln, IF2n or IF5n of the journals published in different individual countries are similar to the results obtained before by the author from the analysis of the citation distribution data of papers of individual authors (K. Sangwal, Journal of Informetrics 7 (2013) 36–49), (2) in contrast to the theoretically expected value of the effectiveness parameter α = 1, the calculated values of α > 1 for journals published in different countries, (3) the trends of the distribution of cited half-lives λn of journals differ from those of Ln, IF2n and IF5n data for different countries, and show one, two or three linear regions, the longest linear regions with low slopes are observed in the case of countries publishing relatively high number of journals, and (4) the product of the Langmuir constant K and the number N of journals for the processes of citations and two- and five-year impact factors of journals published in different countries is constant for a process. The results suggest that: (1) the values of α > 1 are associated with a process that retards the generation of items (i.e. citations or impact factors), the difference (α ? 1) being related to the dissemination of contents of the journals published by a country, and (2) the constancy of KN is related to the publication potential of a country. 相似文献
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The definitions of the rational and real-valued variants of the h-index and g-index are reviewed. It is shown how they can be obtained both graphically and by calculation. Formulae are derived expressing the exact relations between the h-variants and between the g-variants. Subsequently these relations are examined. In a citation context the real h-index is often, but not always, smaller than the rational h-index. It is also shown that the relation between the real and the rational g-index depends on the number of citations of the article ranked g + 1. Maximum differences between h, hr and hrat on the one hand and between g, gr and grat on the other are determined. 相似文献
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A compressed full-text self-index for a text T, of size u, is a data structure used to search for patterns P, of size m, in T, that requires reduced space, i.e. space that depends on the empirical entropy (H
k
or H
0) of T, and is, furthermore, able to reproduce any substring of T. In this paper we present a new compressed self-index able to locate the occurrences of P in O((m + occ)log u) time, where occ is the number of occurrences. The fundamental improvement over previous LZ78 based indexes is the reduction of the search
time dependency on m from O(m
2) to O(m). To achieve this result we point out the main obstacle to linear time algorithms based on LZ78 data compression and expose
and explore the nature of a recurrent structure in LZ-indexes, the suffix tree. We show that our method is very competitive in practice by comparing it against other state of the art compressed
indexes.
相似文献
| Arlindo L. OliveiraEmail: |
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In the present work we introduce a modification of the h-index for multi-authored papers with contribution based author name ranking. The modified h-index is denoted by hmc-index. It employs the framework of the hm-index, which in turn is a straightforward modification of the Hirsch index, proposed by Schreiber. To retain the merit of requiring no additional rearrangement of papers in the hm-index and in order to overcome its shortage of benefiting secondary authors at the expense of primary authors, hmc-index uses combined credit allocation (CCA) to replace fractionalized counting in the hm-index. The hm-index is a special form of hmc-index and fits for papers with equally important authors or alphabetically ordered authorship. There is a possibility of an author of lower contribution to the whole scientific community obtaining a higher hmc-index. Rational hmc-index, denoted by hmcr-index, can avoid it. A fictitious example as a model case and two empirical cases are analyzed. The correlations of the hmcr-index with the h-index and its several variants considering multiple co-authorship are inspected with 30 researchers’ citation data. The results show that the hmcr-index is more reasonable for authors with different contributions. A researcher playing more important roles in significant work will obtain higher hmcr-index. 相似文献
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We consider the following autocompletion search scenario: imagine a user of a search engine typing a query; then with every
keystroke display those completions of the last query word that would lead to the best hits, and also display the best such
hits. The following problem is at the core of this feature: for a fixed document collection, given a set D of documents, and an alphabetical range W of words, compute the set of all word-in-document pairs (w, d) from the collection such that w ∈ W and d ∈ D. We present a new data structure with the help of which such autocompletion queries can be processed, on the average, in
time linear in the input plus output size, independent of the size of the underlying document collection. At the same time,
our data structure uses no more space than an inverted index. Actual query processing times on a large test collection correlate
almost perfectly with our theoretical bound.
相似文献
| Ingmar WeberEmail: |
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The scientific impact of a publication can be determined not only based on the number of times it is cited but also based on the citation speed with which its content is noted by the scientific community. Here we present the citation speed index as a meaningful complement to the h index: whereas for the calculation of the h index the impact of publications is based on number of citations, for the calculation of the speed index it is the number of months that have elapsed since the first citation, the citation speed with which the results of publications find reception in the scientific community. The speed index is defined as follows: a group of papers has the index s if for s of its Np papers the first citation was at least s months ago, and for the other (Np ? s) papers the first citation was ≤s months ago. 相似文献
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Five ratios RH, RT, SH, ST and SZ derived from the three-part division of a set of sources in h-core, h-tail and uncited sources are defined. Dynamic changes in the three independent ratios RH, SH and SZ are studied for six selected topics. Data about these topics are obtained from the Web of Science for scientific papers and Derwent Innovations Index for technical patents. It is observed that all RH- and SH-values decrease when the time span widens, while SZ stays the same or increases; and that all RH- and SH-values for papers are larger than the corresponding values for patents. The shifted Lotka distribution is used in a theoretical interpretation of these empirical phenomena. 相似文献
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《Journal of Informetrics》2014,8(4):972-984
The distribution of cumulative citations L and contributed citations Lf to individual multiauthored papers published by selected authors working in different scientific disciplines is analyzed and discussed using Langmuir-type function: yn = y0[1 − αKn/(1 + Kn)], where yn denotes the total number of normalized cumulative citations ln* and normalized contributed citations lnf* received by individual papers of rank n, y0 is the maximum value of yn when n = 0, α ≥ 1 is an effectiveness parameter, and K is the Langmuir constant related to the dimensionless differential energy Q = ln(KNc), with Nc as the number of papers receiving citations. Relationships between the values of the Langmuir constant K of the distribution function, the number Nc of papers of an individual author receiving citations and the effectiveness parameter α of this function, obtained from analysis of the data of rank-size distributions of the authors, are investigated. It was found that: (1) the quantity KNc obtained from the real citation distribution of papers of various authors working in different disciplines is inversely proportional to (α − 1) with a proportional constant (KNc)0 < 1, (2) the relation KNc = (KNc)0/(α − 1) also holds for the citation distribution of journals published in countries of two different groups, investigated earlier (Sangwal, K. (2013). Journal of Informetrics, 7, 487–504), and (3) deviations of the real citation distribution from curves predicted by the Langmuir-type function are associated with changing activity of sources of generation of items (citations). 相似文献
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Jennifer S. Milligan 《Archival Science》2007,7(4):359-367
Curious Archives examines the creation of the museum of archives, the Musée de l’Histoire de France, at the Imperial Archives
of France under the direction of Leon de Laborde, 1858–1867. This museum was intended as a crucial tool for publicizing the
Archives and educating the public, but also represented a break from the Archives’ role as administrative storehouse both
in practice and in the popular imagination. The museum’s conception and reception reveal conflicts around the Archives’ mission
and contents, particularly regarding public interest, the potential dangers of public curiosity, and nature of documentary
and historical knowledge in nineteenth-century France.
相似文献
| Jennifer S. MilliganEmail: |
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Beatrice S. Bartlett 《Archival Science》2007,7(4):369-390
This article describes the first half century of the Communist government’s supervision and management of the central-government
archives of the last two dynasties. Immediately with the Communist ascent to power in 1949, the new government took great
interest in assembling and protecting the country’s archival documents, readying the Ming-Qing archives for access to scholars,
and preparing for publication of selected materials. By the 1980s Beijing’s Number One Historical Archives, in charge of the
largest holding of Ming-Qing documents, had become the first Chinese authority to complete a full sorting and preliminary
catalogues for such a collection. Moreover, to facilitate searches, an attempt has recently begun to create a subject-heading
system for these and other holdings in the country. In the first half century’s final decades, foreign researchers were admitted
for the first time and tours and international exchanges began to take place.
相似文献
| Beatrice S. BartlettEmail: |