摘要:

AbstractThe similarity and stability analysis of the two partitioning type clustering algorithms, which appeared in this journal recently, are presented with respect to two different metrics. This article also includes other aspects of the algorithms, such as the number and size of the clusters generated, the similarity between the members of a cluster and the corresponding centroid, and other relevant details. In the experiments, a document collection consisting of the titles, abstracts, and keywords of 167 ACM TODS publications was used.

ISSN:0002-8231    

DOI:10.1002/asi.4630360101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThis article describes the design and development of a new type of thesaurus based on lexical‐semantic relations. Relational thesauri have been constructed to perform a new type of term classification. These relational thesauri are generally applicable to any document collection and their maintenance is relatively simple. A series of experiments to evaluate thesauri of this new type have been run on an information retrieval system called IRS at Illinois Institute of Technology. The results of experiments with queries enhanced using thesauri based on several different groups of relations have been compared against performance with the original queries. Thesauri from most groups, except antonyms, made improvements in recall as well as in precision. The best results come from a set of ill‐formed queries with few index terms. These results have been analyzed with both precision‐recall graphs and statistical tests. While thesauri that combine a number of relations together have been most effective in a batch environment, there is reason to believe that individual relations will be more useful in an interactive retrieval system that presents index terms to the user and allows him to choose those that best convey his me

ISSN:0002-8231    

DOI:10.1002/asi.4630360102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractConcepts and techniques used in contemporary social network analysis are applied to a network of journals based on citation. By means of procedures drawing on the notion of structural equivalence, a set of blocks or positions, containing journals, are delineated. These blocks have a very close correspondence to a categorization of the journals based on their aims and objectives, supporting the idea of treating the journals of a discipline as a status‐role relational system. By means of the reduced image of the network, a highly centralized and hierarchical structure appears. Some hypotheses concerning the structure and operation of journal networks are advance

ISSN:0002-8231    

DOI:10.1002/asi.4630360103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractUsing the Random Graph Hypothesis, the statistical validity of co‐citation graphs has been investigated as a function of co‐citation strength for a given value of citation frequency. The results show that for both high and low values of co‐citation strength the partition of cited documents produced by the co‐citation relationship may be statistically invalid. Critical thresholds can be identified that define the limits of statistical validity. Within these limits, there is a narrow region of statistical validity where the associated structures are not an artifact of the clustering procedure and can be interpreted. It is concluded that the choice of citation and co‐citation thresholds can be influenced by formal considerations which insure statistically meaningful partitions rather than arbitrary decisions which can produce meaningless interpretations. Experimental and theoretical implications for the co‐citation graph and other bibliometric structures ar

ISSN:0002-8231    

DOI:10.1002/asi.4630360104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractImmense cultural changes are taking place in contemporary society. We are in the initial stage of a new era in which our society will view itself and its relationship with an increasingly technetronic world in radically different ways. Powered by abundant, proliferating technology, the advent of this new global epoch demands reasoned personal and professional responses reflecting unique modes of thought and behavior. This article discusses these changes and the meaning and depth of their relationship to medical libraries. Ideas for creating organizational environments that allow and encourage people to embrace change and initiate innovations are presented. Only by actively debating and creatively experimenting with these and other ideas will we be able to ensure our continued viability as information specialists and managers in the future.

ISSN:0002-8231    

DOI:10.1002/asi.4630360105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractRecent technological developments are changing the context, and may change the content and form, of personal information systems. Major developments causing such changes are (1) a substantial increase in the commercially available support services, (2) a proliferation of microcomputer systems claiming to support personal systems, (3) the capability to download citations from secondary services into private files, and (4) a developing awareness of, or desire to, incorporate the computer‐based personal system into a broader, integrated information environment which would include other functions such as electronic mail, automated office functions, etc. These developments raise economic questions for the user, will affect efforts to standardize system interfaces, and may bring basic changes in the ways an individual develops and uses his personal information syste

ISSN:0002-8231    

DOI:10.1002/asi.4630360106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe Administration on Aging (AoA) sponsored a national information system known as the SCAN system. The SCAN bibliographic database went on‐line in March 1982. Congress, however, had repealed the authority for the clearinghouse, so the Government let all of the services of SCAN expire by September 1982. The Government then tried to keep the SCAN information accessible by offering it to the private sector. The Government solicited applicants through both theFederal Registerand theCommerce Business Daily.As a result, the American Association of Retired Persons (AARP) and AoA signed an agreement calling for AARP to make much of the SCAN information accessible on‐line and to update

ISSN:0002-8231    

DOI:10.1002/asi.4630360107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0002-8231    

DOI:10.1002/asi.4630360109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0002-8231    

DOI:10.1002/asi.4630360110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0002-8231    

DOI:10.1002/asi.4630360111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY