The network structure of a hyperlinked environment can be a rich source of information about the content of the environment, provided we have effective means for understanding it. We develop a set of algorithmic tools for extracting information from the link structures of such environments, and report on experiments that demonstrate their effectiveness in a variety of context on the World Wide Web. The central issue we address within our framework is the distillation of broad search topics, through the discovery of “authorative” information sources on such topics. We propose and test an algorithmic formulation of the notion of authority, based on the relationship between a set of relevant authoritative pages and the set of “hub pages” that join them together in the link structure. Our formulation has connections to the eigenvectors of certain matrices associated with the link graph; these connections in turn motivate additional heuristrics for link-based analysis.

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Authoritative sources in a hyperlinked environment

We present VOSviewer, a freely available computer program that we have developed for constructing and viewing bibliometric maps. Unlike most computer programs that are used for bibliometric mapping, VOSviewer pays special attention to the graphical representation of bibliometric maps. The functionality of VOSviewer is especially useful for displaying large bibliometric maps in an easy-to-interpret way. The paper consists of three parts. In the first part, an overview of VOSviewer’s functionality for displaying bibliometric maps is provided. In the second part, the technical implementation of specific parts of the program is discussed. Finally, in the third part, VOSviewer’s ability to handle large maps is demonstrated by using the program to construct and display a co-citation map of 5,000 major scientific journals.

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Software survey: VOSviewer, a computer program for bibliometric mapping.

A new form of document coupling called co-citation is defined as the frequency with which two documents are cited together. The co-citation frequency of two scientific papers can be determined by comparing lists of citing documents in the Science Citation Index and counting identical entries. Networks of co-cited papers can be generated for specific scientific specialties, and an example is drawn from the literature of particle physics. Co-citation patterns are found to differ significantly from bibliographic coupling patterns, but to agree generally with patterns of direct citation. Clusters of co-cited papers provide a new way to study the specialty structure of science. They may provide a new approach to indexing and to the creation of SDI profiles.

Co-citation in the scientific literature: A new measure of the relationship between two documents

bibliometrix: An R-tool for comprehensive science mapping analysis

We review the recent rapid progress in the statistical physics of evolving networks. Interest has focused mainly on the structural properties of complex networks in communications, biology, social sciences and economics. A number of giant artificial networks of this kind have recently been created, which opens a wide field for the study of their topology, evolution, and the complex processes which occur in them. Such networks possess a rich set of scaling properties. A number of them are scale-free and show striking resilience against random breakdowns. In spite of the large sizes of these networks, the distances between most of their vertices are short - a feature known as the 'small-world' effect. We discuss how growing networks self-organize into scale-free structures, and investigate the role of the mechanism of preferential linking. We consider the topological and structural properties of evolving networks, and percolation and disease spread on these networks. We present a number of models demonstrat...

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Evolution of networks

Many ongoing selective dissemination systems designers assume that the librarian can be omitted from active participation in execution of the master plan. ISI's four years of experience with ASCA® service have shown that librarians must be an integral part of the system and engage in an active dialogue between users and the machine. Specific examples of how librarians can best serve the information needs of scientists using SDI systems are examined. It is the basic contention of this paper that the librarian should serve as an intermediary between users and the numerous new information media. In this manner the librarian can filter and translate the requirements of individual scientists to conform with the inherent limitations of all machine systems while exploiting their capabilities to the fullest.

The role of the medical librarian in SDI systems.

La ciencia en España desde la perspectiva de las citaciones (1981-1992)

“This year’s Annual Convention will emphasize the unsatisfied needs for information of various segments of our society.” Such was the key sentence of the call for papers issued by our Program Committee in February 1970. Unfortunately, only a few papers seem, in my opinion, to have been clearly focused on the problem we had hoped they would discuss. One that did was Dr. Ralph Lapp’s paper on information gaps between the Congress and the military. I had not expected to hear Dr. Lapp talk about the methodologies that we, as specialists, could put at the disposal of the Congress, in bridging the terrifying information gap between two such paramount sectors of our societ y, but I had hoped that more of us would have suggested how we could apply the expertise we have developed during the last twenty years to perhaps less important, but nonetheless still serious problems now confronting an information-conscious but information-poor society—as you have heard Dr. Shera so eloquently describe it today. I have searched for reasons why it is dit%cult for us to do what Dr. Lapp implies needs doing. It seems not to be that we are unable or unwilling to discover and examine everyday information problems of society. Rather, in thinking about means to correct such problems, we too often confuse complexity with erudition. Dr. Lapp has told us how technologists of the militaryindustrial complex overwhelm our elected representativ& with floods of incomprehensibly complex jargon. In times when the cash boxes of grantfunding and contracting agencies were overflowing, it was as easy to accept such facile proposals as to produce them; but now that grants and contracts are no longer simply there for the asking, scientists must do something to which only a few in this audience are probably accustomed. They must sell an idea, and to sell one must usually be brief, simple, and to the point. With simplicity, brevity, and relevance I have sold more information services after one halfhour with the right man than ever I could have sold during a week’s wideranging discussion of the information problem with every member of a univemity faculty or an industrial research department. But just as we cannot now forego simplicity in the presentation of a proposal, we can no longer afford to overlook it in formulating the substance of what we propose. There are too many problems in this information-poor society that may be susceptible to basically simple solutions. And those problems are too serious to allow us to

Information science and the information-conscious society

Engineers, on the other hand, were rarely seen in the library. They obtained their highly focused information by reading technical reports and recent conference literature. When I showed Current

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Eugene Garfield

Papers

The role of the medical librarian in SDI systems.

La ciencia en España desde la perspectiva de las citaciones (1981-1992)

Information science and the information-conscious society

Why Is the Engineer So Different from the Scientist

Citation indexes in information retrieval