![An overview illustrates the construction and use of dual-map overlays. Citation arcs, cocitation links, and trajectories over time facilitate the study of multiple sets of publications at an interdisciplinary level, an organizational level, and the individual publication level. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]](https://www.researchgate.net/profile/Chaomei-Chen/publication/236039476/figure/fig7/AS:296582177148934@1447722109490/An-overview-illustrates-the-construction-and-use-of-dual-map-overlays-Citation-arcs_Q320.jpg)
![The initial appearance of the user interface, simultaneously showing citing and cited journal base maps. The base map of 10,330 citing journals is on the left. The base map of 10,253 cited journals is on the right. The colors depict clusters identified by Blondel's clustering algorithm. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]](https://www.researchgate.net/profile/Chaomei-Chen/publication/236039476/figure/fig1/AS:289157520871442@1445951933333/The-initial-appearance-of-the-user-interface-simultaneously-showing-citing-and-cited_Q320.jpg)
![The boundary of each cluster is shown to depict how its members are distributed. Clusters in both base maps overlap substantially. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]](https://www.researchgate.net/profile/Chaomei-Chen/publication/236039476/figure/fig9/AS:296582240063489@1447722124031/The-boundary-of-each-cluster-is-shown-to-depict-how-its-members-are-distributed-Clusters_Q320.jpg)
![Citation patterns in an overlay of 405 articles that cited the Wakefield et al. (1998) article. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]](https://www.researchgate.net/profile/Chaomei-Chen/publication/236039476/figure/fig4/AS:296582147788828@1447722102812/Citation-patterns-in-an-overlay-of-405-articles-that-cited-the-Wakefield-etal-1998_Q320.jpg)
![Citation patterns from 2005 to 2006 differ from those in 2004. In terms of the cited patterns, the citations to environment, toxicology, and nutrition in 2004 were no longer observable in 2005 to 2006. Instead, a group of new publications to history, philosophy, and records appeared. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]](https://www.researchgate.net/profile/Chaomei-Chen/publication/236039476/figure/fig11/AS:296582277812224@1447722133200/Citation-patterns-from-2005-to-2006-differ-from-those-in-2004-In-terms-of-the-cited_Q320.jpg)
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Patterns of Connections and Movements in Dual-Map Overlays: A New Method of Publication Portfolio Analysis
Abstract and Figures
Portfolio analysis of the publication profile of a unit of interest, ranging from individuals, organizations, to a scientific field or interdisciplinary programs, aims to inform analysts and decision makers about the position of the unit, where it has been, and where it may go in a complex adaptive environment. A portfolio analysis may aim to identify the gap between the current position of an organization and a goal that it intends to achieve or identify competencies of multiple institutions. We introduce a new visual analytic method for analyzing, comparing, and contrasting characteristics of publication portfolios. The new method introduces a novel design of dual-map thematic overlays on global maps of science. Each publication portfolio can be added as one layer of dual-map overlays over two related but distinct global maps of science, one for citing journals and the other for cited journals. We demonstrate how the new design facilitates a portfolio analysis in terms of patterns emerging from the distributions of citation threads and the dynamics of trajectories as a function of space and time. We first demonstrate the analysis of portfolios defined on a single source article. Then we contrast publication portfolios of multiple comparable units of interest, namely, colleges in universities, corporate research organizations. We also include examples of overlays of scientific fields. We expect the new method will provide new insights to portfolio analysis.
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... The top 10 authors by publication volume in the field of tendon tissue engineering are shown in Fig. 4a. The author with the highest publication volume is Chang, James (35), followed by Chen, Xiao (28) and Gomes, Manuela E. (28). In scientific literature, core authors are those scholars who make significant contributions to a particular field or research direction, and their number is proportional to the square root of the total number of authors in the field [27]. ...
... The top 10 authors by publication volume in the field of tendon tissue engineering are shown in Fig. 4a. The author with the highest publication volume is Chang, James (35), followed by Chen, Xiao (28) and Gomes, Manuela E. (28). In scientific literature, core authors are those scholars who make significant contributions to a particular field or research direction, and their number is proportional to the square root of the total number of authors in the field [27]. ...
... The use of journal overlay analysis can demonstrate the disciplinary relationships between cited and citing literature in the field of tendon tissue engineering [28]. The journal overlay map of the field is shown in Fig. 5c. ...
Introduction
As a significant branch of tissue engineering, tendon tissue engineering has developed rapidly, driven by advancements in new technologies and the refinement of medical theories. This study summarizes its development by analyzing historical evolution, research hotspots, and future trends to reveal core research directions and potential pathways.
Methods
Based on literature from WoS CC (1991–2024) and analyzed using VOSviewer, CiteSpace, and Bibliometrix, the study evaluates publication trends and research patterns.
Results
Findings show continuous growth in annual publications. The United States and China are key contributors with close collaboration. Chang James is the most prolific author, and stable research teams have emerged, though inter-team cooperation remains limited. Acta Biomaterialia publishes the most papers in this field, characterized by interdisciplinary integration. Key research focuses include scaffolds, seed cells, and rotator cuff injuries. Frontiers involve ideal scaffold construction, tendon adhesion prevention, and regeneration strategies. Future directions emphasize novel biomaterials, tendon-bone interface healing, innovative seed cell cultivation, tendon growth microenvironment construction, and clinical translation of research outcomes.
Conclusion
This bibliometric analysis reveals the core research directions and potential pathways in tendon tissue engineering, providing a reference for future studies.
... A dual-map overlay is a visual representation that maps the citation relationships between citing and cited journals (33). This overlay provides a comprehensive view of how research in a specific field is interconnected with other disciplines, highlighting the interdisciplinary flow of knowledge. ...
Background
Diabetes mellitus and sarcopenia are chronic metabolic disorders characterized by bidirectional interactions, frequently coexisting as comorbidities whose interrelationship has garnered increasing scientific attention. This study pioneers a bibliometric analysis to systematically investigate their association, aiming to map the knowledge structure, evolutionary trajectories, current foci, and emerging frontiers within this area.
Methods
We retrieved 2,773 publications from the Web of Science Core Collection from inception until December 26, 2024, and visual analyses were conducted using CiteSpace, VOSviewer, R, and Microsoft Excel. The analysis characterized disciplinary distributions, publication outputs, national/regional contributions, institutional collaborations, authorship networks, journal profiles, references, and keywords.
Results
Annual publications demonstrated sustained growth, with the United States dominating scholarly contributions. Research exhibited marked interdisciplinary integration, although investigations linking type 1 diabetes mellitus with sarcopenia remain limited. Current research hotspots included shared pathological mechanisms such as insulin resistance and chronic inflammation, clinical characterization of specific subtypes such as sarcopenic obesity, imaging-based assessment of muscle dysfunction in diabetes, and the therapeutic efficacy of exercise as an intervention. Mechanistic exploration was determined to be the primary driver of domain advancement.
Conclusion
The field has evolved from theoretical frameworks to clinical applications, highlighting the importance of uncovering common pathophysiological mechanisms and pinpointing potential therapeutic targets. Future priorities include refining screening and diagnostic protocols, optimizing preventive strategies, and developing personalized interventions. Cross-disciplinary innovations integrating multi-omics and precision medicine are poised to reshape this research landscape.
... In this study, bibliometric visualisation was performed using two software packages, CiteSpace (version 6.2.3) and VOSviewer (version 1.6.19). CiteSpace focuses on knowledge structure and evolutionary trends in the temporal dimension of the literature (C. Chen, 2006;C. Chen and Leydesdorff, 2014;Y. Zhu and Hu, 2023), and VOSviewer has advantages in data visualisation and ease of operation in showing literature relationships (Van Eck and Waltman, 2010;Cobo et al. 2011b;Zhong and Lin, 2022;Cândido et al. 2023). The two tools can be used in conjunction to complement each other's strengths and to fully reveal the knowledge structure ...
Despite the widely recognised importance of packaging design’s influence on purchase intention in both academic and industrial spheres, there remains a dearth of comprehensive research at the intersection of these two concepts, particularly as no evaluation in the current field has been conducted through systematic bibliometric analysis. Based on this, this study aims to explore the current state and trends in the research domain of packaging design and purchase intention relationships through a mixed-methods systematic review. A total of 221 academic articles were selected from high-quality journals indexed in the Web of Science (WoS) database. The study employs a hybrid methodology combining bibliometric analysis techniques (including performance analysis and science mapping) with the Scientific Procedures and Rationales for Systematic Literature Reviews (SPAR-4-SLR) protocol for systematic literature reviews, whilst utilising bibliometric visualisation analysis tools CiteSpace and VOSviewer to analyse annual publications, scientific collaboration networks, disciplinary distribution, research hotspots and trends, and key variables. The findings indicate that the five core research themes in this field are: The Role of Packaging in Consumer Decision Process, Visual and Structural Elements of Packaging Design, Product Expectations and Evaluation Induced by Packaging, Packaging Information Communication and Processing, and Environmental Impact and Sustainability of Packaging. Furthermore, this study proposes future research directions using the Theory, Method, Context (TMC) framework. This research not only provides researchers with important research trends in the field but also offers valuable references and guidance for marketers and designers.
... As a crucial tool for quantitatively analyzing the scientific literature structure and evolutionary patterns [24], bibliometrics can precisely identify research hotspot evolution, core knowledge producers, and interdisciplinary interaction modes through high-frequency keyword co-occurrence, collaborative network analysis, and temporal mapping [25]. Compared to methods like meta-analysis focusing on parameter quantitative integration, bibliometrics' core advantage lies in its macro-scale analysis capability to systematically reveal knowledge network characteristics of technological development trajectories (such as knowledge flow direction and interdisciplinary nodes) and social network attributes (like institutional collaboration patterns and national competitiveness landscapes), rather than being limited to statistical parameter inference. ...
Driven by global carbon neutrality goals, biochar has gained significant attention due to its stable carbon sequestration capabilities and environmental benefits. This research employs bibliometric tools such as VOSviewer 1.6.16, Citespace 6.2 R6, and Scimago Graphica to systematically analyze 2076 publications from the Web of Science Core Collection between 2007 and 2024, aiming to clarify the evolutionary trajectory, research hotspots, and international collaboration patterns of biochar carbon sequestration research while identifying future knowledge gaps for innovation. Research results reveal a three-stage developmental characteristic: 2007–2014 was a slow accumulation period for fundamental mechanism exploration, 2015–2020 was an accelerated expansion period driven by policies like the Paris Agreement, and 2021 to the present marks an exponential growth phase of interdisciplinary integration due to global carbon market consolidation. China and the United States are core producing countries, though inter-institutional deep collaboration remains insufficient. Research hotspots have progressively shifted from early biochar preparation and carbon stability to multiple waste materials (such as rice straw and urban carbon sequestration waste) and co-pyrolysis technologies (significantly emerging since 2022), with machine learning applications in process optimization becoming a nascent direction. The study recommends increasing cross-disciplinary research funding, establishing biochar raw material pollution standards, and promoting coordinated policies that combine biochar carbon sequestration with agricultural efficiency to support global carbon reduction objectives. Notably, the research’s reliance on the Web of Science Core Collection may limit coverage of non-English literature and regional studies. By quantitatively analyzing technological evolution and collaboration networks, this study provides a data-driven framework for optimizing biochar carbon sequestration strategies, helping bridge the gap between laboratory potential and actual climate emission reduction, and offering focused action pathways for policymakers and researchers.
... The Dual-Map Overlay visualizes citation relationships between distinct disciplinary domains, aiding researchers in understanding knowledge flow and cross-disciplinary influences (Chen and Leydesdorff, 2014). This analytical tool provides novel insights into the academic impact and intellectual contributions of research entities. ...
Background
Transcranial ultrasound stimulation (TUS) is a non-invasive neuromodulation technique with promising clinical potential. Its therapeutic efficacy and safety are significantly influenced by stimulation parameters. However, the global research hotspots and future research trends of TUS application in the field of rehabilitation are unclear. This study analyzes the status of TUS research. Understand the annual publication trends, international and institutional cooperation pattern and influential authors and journals and keyword hotspot.
Methods
A comprehensive literature search was conducted on the Web of Science core database using TUS-related subject headings until 27 December 2024. Two researchers independently screened articles based on pre-determined inclusion and exclusion criteria. Software packages such as CiteSpace and VOSviewer were used to visualize the results.
Results
A total of 577 literatures were included. The results show that the annual publication volume shows an increasing trend, reaching a peak in 2024. The United States, China and Germany dominated the number of publications, with the largest number of institutions being Harvard University, the University of Toronto and Brigham and Women’s Hospital. Brain stimulation is the journal with the most articles and citations. Research hotspots include transcranial magnetic stimulation, noninvasive brain stimulation, Parkinson’s disease, and Alzheimer’s disease.
Conclusion
A bibliometric analysis of the literature shows that research interest in transcranial ultrasound stimulation is growing rapidly, with annual publications growing exponentially since 2013 and receiving increasing attention from researchers. The findings suggest that TUS is currently used primarily in neurological diseases, particularly in the study of Parkinson’s disease and Alzheimer’s disease. At the same time, it is found that an emerging international cooperation model with the partnership between the United States, China and Germany as the core has gradually taken shape. Although preclinical studies have shown promising neuromodulator effects, the current study suggests that TUS needs to undergo further multicenter clinical validation. These findings provide evidence to guide future research priorities for non-invasive neuromodulation.
Introduction
FcγR (Fc gamma receptor) is a glycoprotein involved in various biological activities, such as inflammation and tumor immunity, and new ideas about the role of FcγR have also been published recently. Our study utilized journals derived from those published from 2004 to 2024 to analyze the research hotspots and cutting-edge ideas in this field.
Method
All publications were searched using the web of science core collection database. VOSviewer, the R package Biblioshiny in R-studio and CiteSpace (version 6.1.R6) were utilized to perform bibliometric analysis which focused on authors, countries, organizations, keywords, etc.
Result
The analysis of this article is based on 6849 articles related to FcγR from 107 countries and 37,487. The most cited reference in FcγR field is the article “Fcgamma Receptors as Regulators of Immune Responses,” authored by Nimmerjahn. Country/region analysis shows that the United States of America (USA) has far more citation frequency and publications than other countries. The most recent hotspots and keywords are “COVID-19” and “SARS-CoV-2.”
Discussion
Through bibliometric analysis, we can clearly recognize the evolution of the field of FcγR research, from the original cellular immunity to tumor immunity to the occurrence of the latest viral immunity, which may guide the direction of research in the field and allow researchers to be more aware of the current status and frontiers of the field.
Kavram olarak dijital aktivizm, toplumsal hareketlere dahil olan bireylerin ve bu hareketlerin katılımcılarının, otorite konumundaki kurum/kişilere karşı taleplerini ifade etmek için dijital medyayı kullandıkları kamusal bir faaliyet olarak tanımlanabilir. Bu çalışmada dijital aktivizm ve toplumsal cinsiyet arasındaki ilişkinin ortaya konulması amaçlanmaktadır. Ortaya çıkan eğilimleri ve gelişmeleri belirlemek için performans analizi ve görselleştirme teknikleri kullanılarak 475 çalışmanın bibliyometrik analizi yapılmıştır. Yazarlar, ülkeler, referanslar ve anahtar kelimelerin sınıflandırmaları, kümeleri ve atıf patlamalarını belirlemek için CiteSpace ve VOSviewer programları birlikte kullanılmıştır. Bu çalışmanın amacı, araştırma alanını şekillendiren temel temaları, iş birliklerini ve eğilimleri belirleme hedefi ile dijital aktivizm ve toplumsal cinsiyet hakkındaki mevcut literatürün kapsamlı bir analizini sağlayarak eğilimleri ortaya koymak ve gelecek yönelimlere dair ön görülerde bulunmaktır. Alanda en çok yayının üretildiği ülkeler sırasıyla Amerika Birleşik Devletleri, İngiltere ve Kanada olarak belirlenmiştir. Alanda öne çıkan dergiler ise Feminist Media Studies, Women's Studies International Forum ve Feminist Theory olarak bulunmuştur. Alanda en üretken yazarlar, Fernandez Romero, Nunez Puente ve Bartlett iken; en çok atıfı alan çalışmaların yazarları ise; Baer (2016), Clark (2016) ve Mendes (2018) olmuştur. En çok kullanılan kelimeler ise “feminizim”, “sosyal medya” “feminist aktivizm”, “dijital aktivizm”, “aktivizm” ve “toplumsal cinsiyet” olarak öne çıkmıştır. Belge ortak atıf analizleri sonucunda dijital feminist aktivizm, sosyal medya aktivizmi ve ırkçılık karşıtı çalışmalar temel kümeler olarak bulgulanmıştır. Yapılan analizler sonucunda dijital aktivizmin toplumsal cinsiyet çalışmalarına yeni bir soluk getirdiği ve gelecekte de bu yöndeki çalışmaların artarak devam edeceği düşünülmektedir.
With the rapid advancement of internet technology and the frequent occurrence of cyberattacks, the importance of cybersecurity continues to expand, making it essential to systematically explore the current state and development trends in this field. This study conducts a visual analysis of international cybersecurity research collected in the Web of Science SSCI Collection using CiteSpace (6.4.R1). The findings indicate a positive development trend in international cybersecurity research, characterized by increasingly significant interdisciplinary features and distinct phases. However, challenges persist in areas such as academic collaboration, journal coverage, and research perspectives. The study suggests that future cybersecurity research will be influenced by more disciplines, further enhancing interdisciplinary integration and achieving breakthroughs in technological innovation, policy formulation, and talent cultivation. The conclusions of this research provide valuable insights for the theoretical and practical advancement of cybersecurity, encouraging innovation and sustained intellectual cooperation within the discipline.
Background
Connexin 43 (Cx43) plays a pivotal role in tumor growth, metastasis, and disease progression. This study employs bibliometric analysis to identify key research trends and emerging hotspots in Cx43-related solid tumor research.
Methods
In December 2024, the Web of Science Core Collection (WoSCC) database was searched for publications on Cx43 in solid tumor research from 2000 to 2024. Bibliometric analysis and data visualization were primarily conducted using CiteSpace, VOSviewer, and Bibliometrix, with a focus on visualizing aspects such as countries, institutions, journals, authors, references, and keywords in the field.
Results
A total of 1,666 publications were retrieved, with the annual number of articles and citations continuing to grow. The United States and China had the highest number of publications, while the University of Western Ontario in Canada was the leading institution, with the most publications by Christian C.G. Nau. Lampe, P.D. was the most cited author. The International Journal of Molecular Sciences was the most frequently published journal, and the Journal of Biological Chemistry was the most frequently co-cited journal. High-frequency keywords included phosphorylation, breast cancer, gastric cancer, prognostic markers, anti-tumor immune response, and drug resistance.
Conclusion
Contemporary research focuses on the role of Cx43 phosphorylation in tumorigenesis, progression, and metastasis, its potential as a prognostic biomarker, and its critical role as an immunotherapeutic target and in tumor drug resistance. These studies provide a comprehensive analysis for a deeper understanding of the role of Cx43 in solid tumors and help to promote further research in this area.
We present a novel approach to visually locate bodies of research within the sciences, both at each moment of time and dynamically. This article describes how this approach fits with other efforts to locally and globally map scientific outputs. We then show how these science overlay maps help benchmark, explore collaborations, and track temporal changes, using examples of universities, corporations, funding agencies, and research topics. We address conditions of application, with their advantages, downsides and limitations. Overlay maps especially help investigate the increasing number of scientific developments and organisations that do not fit within traditional disciplinary categories. We make these tools accessible to help researchers explore the ongoing socio-cognitive transformation of science and technology systems. Comment: 40 pages, 6 Figures
A standard approach to large network visualization is to provide an overview of the network and a detailed view of a small component of the graph centred around a focal node. The user explores the network by changing the focal node in the detailed view or by changing the level of detail of a node or cluster. For scalability, fast force-based layout algorithms are used for the overview and the detailed view. However, using the same layout algorithm in both views is problematic since layout for the detailed view has different requirements to that in the overview. Here we present a model in which constrained graph layout algorithms are used for layout in the detailed view. This means the detailed view has high-quality layout including sophisticated edge routing and is customisable by the user who can add placement constraints on the layout. Scalability is still ensured since the slower layout techniques are only applied to the small subgraph shown in the detailed view. The main technical innovations are techniques to ensure that the overview and detailed view remain synchronized, and modifying constrained graph layout algorithms to support smooth, stable layout. The key innovation supporting stability are new dynamic graph layout algorithms that preserve the topology or structure of the network when the user changes the focus node or the level of detail by in situ semantic zooming. We have built a prototype tool and demonstrate its use in two application domains, UML class diagrams and biological networks. Index Terms—Graph drawing, constraints, stress majorization, force directed algorithms, multidimensional scaling.
Retracting published scientific articles is increasingly common. Retraction is a self-correction mechanism of the scientific community to maintain and safeguard the integrity of scientific literature. However, a retracted article may pose a profound and long-lasting threat to the credibility of the literature. New articles may unknowingly build their work on false claims made in retracted articles. Such dependencies on retracted articles may become implicit and indirect. Consequently, it becomes increasingly important to detect implicit and indirect threats. In this article, our aim is to raise the awareness of the potential threats of retracted articles even after their retraction and demonstrate a visual analytic study of retracted articles with reference to the rest of the literature and how their citations are influenced by their retraction. The context of highly cited retracted articles is visualized in terms of a co-citation network as well as the distribution of articles that have high-order citation dependencies on retracted articles. Survival analyses of time to retraction and postretraction citation are included. Sentences that explicitly cite retracted articles are extracted from full-text articles. Transitions of topics over time are depicted in topic-flow visualizations. We recommend that new visual analytic and science mapping tools should take retracted articles into account and facilitate tasks specifically related to the detection and monitoring of retracted articles.
Using the option Analyze Results with the Web of Science, one can directly generate overlays onto global journal maps of science. The maps are based on the 10,000+ journals contained in the Journal Citation Reports (JCR) of the Science and Social Sciences Citation Indices (2011). The disciplinary diversity of the retrieval is measured in terms of Rao-Stirling's “quadratic entropy” (Izsák & Papp, 1995). Since this indicator of interdisciplinarity is normalized between 0 and 1, interdisciplinarity can be compared among document sets and across years, cited or citing. The colors used for the overlays are based on Blondel, Guillaume, Lambiotte, and Lefebvre's (2008) community-finding algorithms operating on the relations among journals included in the JCR. The results can be exported from VOSViewer with different options such as proportional labels, heat maps, or cluster density maps. The maps can also be web-started or animated (e.g., using PowerPoint). The “citing” dimension of the aggregated journal–journal citation matrix was found to provide a more comprehensive description than the matrix based on the cited archive. The relations between local and global maps and their different functions in studying the sciences in terms of journal literatures are further discussed: Local and global maps are based on different assumptions and can be expected to serve different purposes for the explanation.
We report on the development of an interface to the US Patent and Trademark
Office (USPTO) that allows for the mapping of patent portfolios as overlays to
basemaps constructed from citation relations among all patents contained in
this database during the period 1976-2011. Both the interface and the data are
in the public domain; the freeware programs VOSViewer and/or Pajek can be used
for the visualization. These basemaps and overlays can be generated at both the
3-digit and 4-digit levels of the International Patent Classifications (IPC) of
the World Intellectual Property Organization (WIPO). The basemaps can provide a
stable mental framework for analysts to follow developments over searches for
different years, which can be animated. The full flexibility of the advanced
search engines of USPTO are available for generating sets of patents and/or
patent applications which can thus be visualized and compared. This instrument
allows for addressing questions about technological distance, diversity in
portfolios, and animating the developments of both technologies and
technological capacities of organizations over time.
A critical part of a scientific activity is to discern how a new idea is related to what we know and what may become possible. As the number of new scientific publications arrives at a rate that rapidly outpaces our capacity of reading, analyzing, and synthesizing scientific knowledge, we need to augment ourselves with information that can guide us through the rapidly growing intellectual space effectively. In this article, we address a fundamental issue concerning with what information may serve as early signs of potentially valuable ideas. In particular, we are interested in information that is routinely available and derivable upon the publication of a scientific paper without assuming the availability of additional information such as its usage and citations. We propose a theoretical and computational model that predicts the potential of a scientific publication in terms of the degree to which it alters the intellectual structure of the state of the art. The structural variation approach focuses on the novel boundary-spanning connections introduced by a new article to the intellectual space. We validate the role of boundaryspanning in predicting future citations using three metrics of structural variation, namely, modularity change rate, cluster linkage, and centrality divergence, along with more commonly studied predictors of citations such as the number of co-authors, the number of cited references, and the number of pages. Main
Global maps of science can be used as a reference system to chart career trajectories, the location of emerging research frontiers, or the expertise profiles of institutes or nations. This paper details data preparation, analysis, and layout performed when designing and subsequently updating the UCSD map of science and classification system. The original classification and map use 7.2 million papers and their references from Elsevier's Scopus (about 15,000 source titles, 2001-2005) and Thomson Reuters' Web of Science (WoS) Science, Social Science, Arts & Humanities Citation Indexes (about 9,000 source titles, 2001-2004)-about 16,000 unique source titles. The updated map and classification adds six years (2005-2010) of WoS data and three years (2006-2008) from Scopus to the existing category structure-increasing the number of source titles to about 25,000. To our knowledge, this is the first time that a widely used map of science was updated. A comparison of the original 5-year and the new 10-year maps and classification system show (i) an increase in the total number of journals that can be mapped by 9,409 journals (social sciences had a 80% increase, humanities a 119% increase, medical (32%) and natural science (74%)), (ii) a simplification of the map by assigning all but five highly interdisciplinary journals to exactly one discipline, (iii) a more even distribution of journals over the 554 subdisciplines and 13 disciplines when calculating the coefficient of variation, and (iv) a better reflection of journal clusters when compared with paper-level citation data. When evaluating the map with a listing of desirable features for maps of science, the updated map is shown to have higher mapping accuracy, easier understandability as fewer journals are multiply classified, and higher usability for the generation of data overlays, among others.
We explain the barycentre method and show how to apply it in a practical situation. A country's mean centre of publica-tion, or publication barycentre, is defined and its evolution is studied in the case of China's centre of publication. Data for this application are taken from the Chinese Science Cita-tion Database (CSCD). It is shown that China's publication barycentre slowly moves to the south and that it approaches the population barycentre. Tentative explanations for this southward movement, based on economic and educational considerations, are given. It is observed that inequality in publication between administrative units (regions) decreases slowly.
With the program HistCite™ it is possible to generate and visualize the most relevant papers in a set of documents retrieved from the Science Citation Index. Historical reconstructions of scientific developments can be represented chronologically as developments in networks of citation relations extracted from scientific literature. This study aims to go beyond the historical reconstruction of scientific knowledge, enriching the output of HistCite™ with algorithms from social-network analysis and information theory. Using main-path analysis, it is possible to highlight the structural backbone in the development of a scientific field. The expected information value of the message can be used to indicate whether change in the distribution (of citations) has occurred to such an extent that a path-dependency is generated. This provides us with a measure of evolutionary change between subsequent documents. The forgetting and rewriting of historically prior events at the research front can thus be indicated. These three methods - HistCite, main path and path dependent transitions - are applied to a set of documents related to fullerenes and the fullerene-like structures known as nanotubes.