2,200 research outputs found
A unified approach to mapping and clustering of bibliometric networks
In the analysis of bibliometric networks, researchers often use mapping and
clustering techniques in a combined fashion. Typically, however, mapping and
clustering techniques that are used together rely on very different ideas and
assumptions. We propose a unified approach to mapping and clustering of
bibliometric networks. We show that the VOS mapping technique and a weighted
and parameterized variant of modularity-based clustering can both be derived
from the same underlying principle. We illustrate our proposed approach by
producing a combined mapping and clustering of the most frequently cited
publications that appeared in the field of information science in the period
1999-2008
Construction of a Pragmatic Base Line for Journal Classifications and Maps Based on Aggregated Journal-Journal Citation Relations
A number of journal classification systems have been developed in
bibliometrics since the launch of the Citation Indices by the Institute of
Scientific Information (ISI) in the 1960s. These systems are used to normalize
citation counts with respect to field-specific citation patterns. The best
known system is the so-called "Web-of-Science Subject Categories" (WCs). In
other systems papers are classified by algorithmic solutions. Using the Journal
Citation Reports 2014 of the Science Citation Index and the Social Science
Citation Index (n of journals = 11,149), we examine options for developing a
new system based on journal classifications into subject categories using
aggregated journal-journal citation data. Combining routines in VOSviewer and
Pajek, a tree-like classification is developed. At each level one can generate
a map of science for all the journals subsumed under a category. Nine major
fields are distinguished at the top level. Further decomposition of the social
sciences is pursued for the sake of example with a focus on journals in
information science (LIS) and science studies (STS). The new classification
system improves on alternative options by avoiding the problem of randomness in
each run that has made algorithmic solutions hitherto irreproducible.
Limitations of the new system are discussed (e.g. the classification of
multi-disciplinary journals). The system's usefulness for field-normalization
in bibliometrics should be explored in future studies.Comment: accepted for publication in the Journal of Informetrics, 20 July 201
CitNetExplorer: A new software tool for analyzing and visualizing citation networks
We present CitNetExplorer, a new software tool for analyzing and visualizing
citation networks of scientific publications. CitNetExplorer can for instance
be used to study the development of a research field, to delineate the
literature on a research topic, and to support literature reviewing. We first
introduce the main concepts that need to be understood when working with
CitNetExplorer. We then demonstrate CitNetExplorer by using the tool to analyze
the scientometric literature and the literature on community detection in
networks. Finally, we discuss some technical details on the construction,
visualization, and analysis of citation networks in CitNetExplorer
Bibliometric cartography of information retrieval research by using co-word analysis
The aim of this study is to map the intellectual structure of the field of Information Retrieval (IR) during the period of 1987-1997. Co-word analysis was employed to reveal patterns and trends in the IR field by measuring the association strengths of terms representative of relevant publications or other texts produced in IR field. Data were collected from Science Citation Index (SCI) and Social Science Citation Index (SSCI) for the period of 1987-1997. In addition to the keywords added by the SCI and SSCI databases, other important keywords were extracted from titles and abstracts manually. These keywords were further standardized using vocabulary control tools. In order to trace the dynamic changes of the IR field, the whole 11-year period was further separated into two consecutive periods: 1987-1991 and 1992-1997. The results show that the IR field has some established research themes and it also changes rapidly to embrace new themes
Software tools for conducting bibliometric analysis in science: An up-to-date review
Bibliometrics has become an essential tool for assessing and analyzing the output of scientists, cooperation between
universities, the effect of state-owned science funding on national research and development performance and educational
efficiency, among other applications. Therefore, professionals and scientists need a range of theoretical and practical
tools to measure experimental data. This review aims to provide an up-to-date review of the various tools available
for conducting bibliometric and scientometric analyses, including the sources of data acquisition, performance analysis
and visualization tools. The included tools were divided into three categories: general bibliometric and performance
analysis, science mapping analysis, and libraries; a description of all of them is provided. A comparative analysis of the
database sources support, pre-processing capabilities, analysis and visualization options were also provided in order to
facilitate its understanding. Although there are numerous bibliometric databases to obtain data for bibliometric and
scientometric analysis, they have been developed for a different purpose. The number of exportable records is between
500 and 50,000 and the coverage of the different science fields is unequal in each database. Concerning the analyzed
tools, Bibliometrix contains the more extensive set of techniques and suitable for practitioners through Biblioshiny.
VOSviewer has a fantastic visualization and is capable of loading and exporting information from many sources. SciMAT
is the tool with a powerful pre-processing and export capability. In views of the variability of features, the users need to
decide the desired analysis output and chose the option that better fits into their aims
Journal portfolio analysis for countries, cities, and organizations: maps and comparisons
Using Web of Science data, portfolio analysis in terms of journal coverage can be projected onto a base map for units of analysis such as countries, cities, universities, and firms. The units of analysis under study can be compared statistically across the 10,000+ journals. The interdisciplinarity of the portfolios is measured using Rao-Stirling diversity or Zhang et al.'s improved measure 2D3. At the country level we find regional differentiation (e.g., Latin American or Asian countries), but also a major divide between advanced and less-developed countries. Israel and Israeli cities outperform other nations and cities in terms of diversity. Universities appear to be specifically related to firms when a number of these units are exploratively compared. The instrument is relatively simple and straightforward, and one can generalize the application to any document set retrieved from the Web of Science (WoS). Further instruction is provided online at http://www.leydesdorff.net/portfolio
Global Maps of Science based on the new Web-of-Science Categories
In August 2011, Thomson Reuters launched version 5 of the Science and Social
Science Citation Index in the Web of Science (WoS). Among other things, the 222
ISI Subject Categories (SCs) for these two databases in version 4 of WoS were
renamed and extended to 225 WoS Categories (WCs). A new set of 151 Subject
Categories (SCs) was added, but at a higher level of aggregation. Since we
previously used the ISI SCs as the baseline for a global map in Pajek (Rafols
et al., 2010) and brought this facility online (at
http://www.leydesdorff.net/overlaytoolkit), we recalibrated this map for the
new WC categories using the Journal Citation Reports 2010. In the new
installation, the base maps can also be made using VOSviewer (Van Eck &
Waltman, 2010).Comment: Scientometrics, in pres
Knowledge Integration and Diffusion: Measures and Mapping of Diversity and Coherence
I present a framework based on the concepts of diversity and coherence for
the analysis of knowledge integration and diffusion. Visualisations that help
understand insights gained are also introduced. The key novelty offered by this
framework compared to previous approaches is the inclusion of cognitive
distance (or proximity) between the categories that characterise the body of
knowledge under study. I briefly discuss the different methods to map the
cognitive dimension
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