arXiv subjects

Loet Leydesdorff

Publications and source records attributed to Loet Leydesdorff.

At least 73 records · Page 4Linked to original sources

arXiv2016

Identification of long-term concept-symbols among citations: Can documents be clustered in terms of common intellectual histories?

"Citation classics" are not only highly cited, but also cited during several decades. We test whether the peaks in the spectrograms generated by Reference Publication Years Spectroscopy (RPYS) indicate such long-term impact by comparing across RPYS for subsequent time intervals. Multi-RPYS enables us to distinguish between short-term citation peaks at the research front that decay within ten years versus historically constitutive (long-term) citations that function as concept symbols (Small, 1978). Using these constitutive citations, one is able to cluster document sets (e.g., journals) in terms of intellectually shared histories. We test this premise by clustering 40 journals in the Web of Science Category of Information and Library Science using multi-RPYS. It follows that RPYS can not only be used for retrieving roots of sets under study (cited), but also for algorithmic historiography of the citing sets. Significant references are historically rooted symbols among other citations that function as currency.

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arXiv2015

The Globalization of Academic Entrepreneurship? The Recent Growth (2009-2014) in University Patenting Decomposed

The contribution of academia to US patents has become increasingly global. Following a pause, with a relatively flat rate, from 1998 to 2008, the long-term trend of university patenting rising as a share of all patenting has resumed, driven by the internationalization of academic entrepreneurship and the persistence of US university technology transfer. We disaggregate this recent growth in university patenting at the US Patent and Trademark Organization (USPTO) in terms of nations and patent classes. Foreign patenting in the US has almost doubled during the period 2009-2014, mainly due to patenting by universities in Taiwan, Korea, China, and Japan. These nations compete with the US in terms of patent portfolios, whereas most European countries--with the exception of the UK--have more specific portfolios, mainly in the bio-medical fields. In the case of China, Tsinghua University holds 63% of the university patents in USPTO, followed by King Fahd University with 55.2% of the national portfolio.

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arXiv2015

Regional and Global Science: Latin American and Caribbean publications in the SciELO Citation Index and the Web of Science

We compare the visibility of Latin American and Caribbean (LAC) publications in the Core Collection indexes of the Web of Science (WoS)--Science Citation Index Expanded, Social Sciences Citation Index, and Arts & Humanities Citation Index--and the SciELO Citation Index (SciELO CI) which was integrated into the larger WoS platform in 2014. The purpose of this comparison is to contribute to our understanding of the communication of scientific knowledge produced in Latin America and the Caribbean, and to provide some reflections on the potential benefits of the articulation of regional indexing exercises into WoS for a better understanding of geographic and disciplinary contributions. How is the regional level of SciELO CI related to the global range of WoS? In WoS, LAC authors are integrated at the global level in international networks, while SciELO has provided a platform for interactions among LAC researchers. The articulation of SciELO into WoS may improve the international visibility of the regional journals, but at the cost of independent journal inclusion criteria.

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arXiv2015

Networks of reader and country status: An analysis of Mendeley reader statistics

The number of papers published in journals indexed by the Web of Science core collection is steadily increasing. In recent years, nearly two million new papers were published each year; somewhat more than one million papers when primary research papers are considered only (articles and reviews are the document types where primary research is usually reported or reviewed). However, who reads these papers? More precisely, which groups of researchers from which (self-assigned) scientific disciplines and countries are reading these papers? Is it possible to visualize readership patterns for certain countries, scientific disciplines, or academic status groups? One popular method to answer these questions is a network analysis. In this study, we analyze Mendeley readership data of a set of 1,133,224 articles and 64,960 reviews with publication year 2012 to generate three different kinds of networks: (1) The network based on disciplinary affiliations of Mendeley readers contains four groups: (i) biology, (ii) social science and humanities (including relevant computer science), (iii) bio-medical sciences, and (iv) natural science and engineering. In all four groups, the category with the addition "miscellaneous" prevails. (2) The network of co-readers in terms of professional status shows that a common interest in papers is mainly shared among PhD students, Master's students, and postdocs. (3) The country network focusses on global readership patterns: a group of 53 nations is identified as core to the scientific enterprise, including Russia and China as well as two thirds of the OECD (Organisation for Economic Co-operation and Development) countries.

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arXiv2015

Replicability and the public/private divide

In a recent letter, Carlos Vilchez-Roman criticizes Bornmann et al. (2015) for using data which cannot be reproduced without access to an in-house version of the Web-of-Science (WoS) at the Max Planck Digital Libraries (MPDL, Munich). We agree with the norm of replicability and therefore returned to our data. Is the problem only a practical one of automation or does the in-house processing add analytical value to the data? Is the newly emerging situation in any sense different from a further professionalization of the field? In our opinion, a political economy of science indicators has in the meantime emerged with a competitive dynamic that affects the intellectual organization of the field.

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arXiv2015

Strategic Intelligence on Emerging Technologies: Scientometric Overlay Mapping

This paper examines the use of scientometric overlay mapping as a tool of 'strategic intelligence' to aid the governance of emerging technologies. We develop an integrative synthesis of different overlay mapping techniques and associated perspectives on technological emergence across the geographical, social, and cognitive spaces. To do so, we longitudinally analyse (with publication and patent data) three case-studies of emerging technologies in the medical domain. These are: RNA interference (RNAi), Human Papilloma Virus (HPV) testing technologies for cervical cancer, and Thiopurine Methyltransferase (TPMT) genetic testing. Given the flexibility (i.e. adaptability to different sources of data) and granularity (i.e. applicability across multiple levels of data aggregation) of overlay mapping techniques, we argue that these techniques can favour the integration and comparison of results from different contexts and cases, thus potentially functioning as platform for a 'distributed' strategic intelligence for analysts and decision-makers.

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arXiv2015

Can "Hot Spots" in the Sciences Be Mapped Using the Dynamics of Aggregated Journal-Journal Citation Relations?

Using three years of the Journal Citation Reports (2011, 2012, and 2013), indicators of transitions in 2012 (between 2011 and 2013) are studied using methodologies based on entropy statistics. Changes can be indicated at the level of journals using the margin totals of entropy production along the row or column vectors, but also at the level of links among journals by importing the transition matrices into network analysis and visualization programs (and using community-finding algorithms). Seventy-four journals are flagged in terms of discontinuous changes in their citations; but 3,114 journals are involved in "hot" links. Most of these links are embedded in a main component; 78 clusters (containing 172 journals) are flagged as potential "hot spots" emerging at the network level. An additional finding is that PLoS ONE introduced a new communication dynamics into the database. The limitations of the methodology are elaborated using an example. The results of the study indicate where developments in the citation dynamics can be considered as significantly unexpected. This can be used as heuristic information; but what a "hot spot" in terms of the entropy statistics of aggregated citation relations means substantively can be expected to vary from case to case.

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arXiv2015

The Normalization of Occurrence and Co-occurrence Matrices in Bibliometrics using Cosine Similarities and Ochiai Coefficients

We prove that Ochiai similarity of the co-occurrence matrix is equal to cosine similarity in the underlying occurrence matrix. Neither the cosine nor the Pearson correlation should be used for the normalization of co-occurrence matrices because the similarity is then normalized twice, and therefore over-estimated; the Ochiai coefficient can be used instead. Results are shown using a small matrix (5 cases, 4 variables) for didactic reasons, and also Ahlgren et al.'s (2003) co-occurrence matrix of 24 authors in library and information sciences. The over-estimation is shown numerically and will be illustrated using multidimensional scaling and cluster dendograms. If the occurrence matrix is not available (such as in internet research or author co-citation analysis) using Ochiai for the normalization is preferable to using the cosine.

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arXiv2015

Can Technology Life-Cycles Be Indicated by Diversity in Patent Classifications? The crucial role of variety

In a previous study of patent classifications in nine material technologies for photovoltaic cells, Leydesdorff et al. (2015) reported cyclical patterns in the longitudinal development of Rao-Stirling diversity. We suggested that these cyclical patterns can be used to indicate technological life-cycles. Upon decomposition, however, the cycles are exclusively due to increases and decreases in the variety of the classifications, and not to disparity or technological distance, measured as (1 - cosine). A single frequency component can accordingly be shown in the periodogram. Furthermore, the cyclical patterns are associated with the numbers of inventors in the respective technologies. Sometimes increased variety leads to a boost in the number of inventors, but in early phases--when the technology is still under constructio--it can also be the other way round. Since the development of the cycles thus seems independent of technological distances among the patents, the visualization in terms of patent maps can be considered as addressing an analytically different set of research questions.

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arXiv2015

Can Intellectual Processes in the Sciences Also Be Simulated? The Anticipation and Visualization of Possible Future States

Socio-cognitive action reproduces and changes both social and cognitive structures. The analytical distinction between these dimensions of structure provides us with richer models of scientific development. In this study, I assume that (i) social structures organize expectations into belief structures that can be attributed to individuals and communities; (ii) expectations are specified in scholarly literature; and (iii) intellectually the sciences (disciplines, specialties) tend to self-organize as systems of rationalized expectations. Whereas social organizations remain localized, academic writings can circulate, and expectations can be stabilized and globalized using symbolically generalized codes of communication. The intellectual restructuring, however, remains latent as a second-order dynamics that can be accessed by participants only reflexively. Yet, the emerging "horizons of meaning" provide feedback to the historically developing organizations by constraining the possible future states as boundary conditions. I propose to model these possible future states using incursive and hyper-incursive equations from the computation of anticipatory systems. Simulations of these equations enable us to visualize the couplings among the historical--i.e., recursive--progression of social structures along trajectories, the evolutionary--i.e., hyper-incursive--development of systems of expectations at the regime level, and the incursive instantiations of expectations in actions, organizations, and texts.

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arXiv2015

Simple arithmetic versus intuitive understanding: The case of the impact factor

We show that as a consequence of basic properties of elementary arithmetic journal impact factors show a counterintuitive behaviour with respect to adding non-cited articles. Synchronous as well as diachronous journal impact factors are affected. Our findings provide a rationale for not taking uncitable publications into account in impact factor calculations, at least if these items are truly uncitable.

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arXiv2015

Scientometrics and Science Studies: From Words and Co-Words to Information and Probabilistic Entropy

The tension between qualitative theorizing and quantitative methods is pervasive in the social sciences, and poses a constant challenge to empirical research. But in science studies as an interdisciplinary specialty, there are additional reasons why a more reflexive consciousness of the differences among the relevant disciplines is necessary. How can qualitative insights from the history of ideas and the sociology of science be combined with the quantitative perspective? By using the example of the lexical and semantic value of word occurrences, the issue of qualitatively different meanings of the same phenomena is discussed as a methodological problem. Nine criteria for methods which are needed for the development of science studies as an integrated enterprise can then be specified. Information calculus is suggested as a method which can comply with these criteria.

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arXiv2015

The Dynamics of Triads in Aggregated Journal-Journal Citation Relations: Specialty Developments at the Above-Journal Level

Dyads of journals related by citations can agglomerate into specialties through the mechanism of triadic closure. Using the Journal Citation Reports 2011, 2012, and 2013, we analyze triad formation as indicators of integration (specialty growth) and disintegration (restructuring). The strongest integration is found among the large journals that report on studies in different scientific specialties, such as PLoS ONE, Nature Communications, Nature, and Science. This tendency towards large-scale integration has not yet stabilized. Using the Islands algorithm, we also distinguish 51 local maxima of integration. We zoom into the cited articles that carry the integration for: (i) a new development within high-energy physics and (ii) an emerging interface between the journals Applied Mathematical Modeling and the International Journal of Advanced Manufacturing Technology. In the first case, integration is brought about by a specific communication reaching across specialty boundaries, whereas in the second, the dyad of journals indicates an emerging interface between specialties. These results suggest that integration picks up substantive developments at the specialty level. An advantage of the bottom-up method is that no ex ante classification of journals is assumed in the dynamic analysis.

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arXiv2015

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 on 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 (in press) 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 WoS. Further instruction is provided online at http://www.leydesdorff.net/portfolio .

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arXiv2015

Recent Developments in China-U.S. Cooperation in Science

China's remarkable gains in science over the past 25 years have been well documented (e.g., Jin and Rousseau, 2005a; Zhou and Leydesdorff, 2006; Shelton & Foland, 2009) but it is less well known that China and the United States have become each other's top collaborating country. Science and technology has been a primary vehicle for growing the bilateral relationship between China and the United States since the opening of relations between the two countries in the late 1970s. During the 2000s, the scientific relationship between China and the United States--as measured in coauthored papers--showed significant growth. Chinese scientists claim first authorship much more frequently than U.S. counterparts by the end of the decade. The sustained rate of increase of collaboration with one other country is unprecedented on the U.S. side. Even growth in relations with eastern European nations does not match the growth in the relationship between China and the United States. Both countries can benefit from the relationship, but for the U.S., greater benefit would come from a more targeted strategy.

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arXiv2015

Highly-cited papers in Library and Information Science (LIS): Authors, institutions, and network structures

As a follow-up to the highly-cited authors list published by Thomson Reuters in June 2014, we analyze the top-1% most frequently cited papers published between 2002 and 2012 included in the Web of Science (WoS) subject category "Information Science & Library Science." 798 authors contributed to 305 top-1% publications; these authors were employed at 275 institutions. The authors at Harvard University contributed the largest number of papers, when the addresses are whole-number counted. However, Leiden University leads the ranking, if fractional counting is used. Twenty-three of the 798 authors were also listed as most highly-cited authors by Thomson Reuters in June 2014 (http://highlycited.com/). Twelve of these 23 authors were involved in publishing four or more of the 305 papers under study. Analysis of co-authorship relations among the 798 highly-cited scientists shows that co-authorships are based on common interests in a specific topic. Three topics were important between 2002 and 2012: (1) collection and exploitation of information in clinical practices, (2) the use of internet in public communication and commerce, and (3) scientometrics.

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arXiv2015

A Review of Theory and Practice in Scientometrics

Scientometrics is the study of the quantitative aspects of the process of science as a communication system. It is centrally, but not only, concerned with the analysis of citations in the academic literature. In recent years it has come to play a major role in the measurement and evaluation of research performance. In this review we consider: the historical development of scientometrics, sources of citation data, citation metrics and the "laws" of scientometrics, normalisation, journal impact factors and other journal metrics, visualising and mapping science, evaluation and policy, and future developments.

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arXiv2015

Bibliometrics/Citation networks

In addition to shaping social networks, for example, in terms of co-authorship relations, scientific communications induce and reproduce cognitive structures. Scientific literature is intellectually organized in terms of disciplines and specialties; these structures are reproduced and networked reflexively by making references to the authors, concepts and texts embedded in these literatures. The concept of a cognitive structure was introduced in social network analysis (SNA) in 1987 by David Krackhardt, but the focus in SNA has hitherto been on cognition as a psychological attribute of human agency. In bibliometrics, and in science and technology studies (STS) more generally, socio-cognitive structures refer to intellectual organization at the supra-individual level. This intellectual organization emerges and is reproduced by the collectives of authors who are organized not only in terms of inter-personal relations, but also more abstractly in terms of codes of communication that are field-specific. Citations can serve as indicators of this codification process.

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