A Spatio-temporal Scientometrics Framework

for Measuring the Citation Impact of

Publications and Scientists

Song Gao, Yingjie Hu, Krzysztof Janowicz, Grant Mckenzie

Space and Time Knowledge Organization Lab (STKO)

University of California Santa Barbara

http://stko.geog.ucsb.edu

Gao, S., Hu, Y., Janowicz, K., & McKenzie, G. (2013, November). A spatiotemporal scientometrics framework for

exploring the citation impact of publications and scientists. In Proceedings of the 21st ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems(pp. 204-213). ACM.

“Knowledge is power.”

not only about knowledge itself

but also about how it spreads out.

Motivation

• Publication citations have great meanings

– Quality of the research

– Recognition among the research community

– Influence of a research

– Evaluation of a individual researcher

e.g. h-index

Motivation

• Web of Science

Motivation

• Google Scholar

Motivation

• Microsoft Academic Search

Motivation

• The number of citations has often been used to

measure the influence of scientific publications.

• Question: Can we know the spatial impact of a

paper by just looking at only a number?

STKO Citation Map

• - Searching publications using keywords or author names

• - Geolocating publications according to the first author’s institution

• - Visualizing how a publication is cited by researchers in different countries over the years

• - Discovering potential collaborators in different regions who have cited your publication frequently

• - Sharing the spatial patterns of your citations with your friends on social media (e.g., Facebook, Twitter, and Google Plus)

http://stko-work.geog.ucsb.edu:8080/map/

Demo

http://stko-work.geog.ucsb.edu:8080/map/

Data sources

• Publication, citation, and author’s information

are provided by Microsoft Academic Search.

• Basemap data is from OpenStreetMap, and

rendered by CloudMade.

Spatial-temporal Analysis of

Scientometrics

Related work

• Scientific activities such as co-publication,

citation, and labor mobility display clear spatial

patterns (Frenken et al., 2009)

• The publications are highly clustered in a few

countries and co-publications tend to occur

domestically rather than internationally.

• Glänzel (2001) and Leydesdorff (2010)

Related work• Prof. Michael Batty: The Geography of Scientific Citation

Related Work

Börner, K., Penumarthy, S., Meiss, M., & Ke, W. (2006). Mapping the diffusion of scholarly knowledge among major US research institutions. Scientometrics,68(3), 415-426.

Insights

• Discussions about spatio-temporal patterns

• The role of distance in citation patterns

• Geospatial citation index (s-index) for

individual researchers

For Publications

(1) Categorical Place Impact

(2) Spatio-Temporal Density Estimation

(3) Cartograms

(4) Distance Distribution Curves of Citations

(5) Spatial Point Pattern Analysis

(1) Categorical Place Impact

• Quantitatively measure geospatial impact

based on the hierarchical structure of places

• Granularity: institution, ZIP, town/city,

county/province, state, country

– Addr. Extraction: e.g., Department of Geography, University of California Santa Barbara, Santa

Barbara, CA 93106, United States.

– Reverse-Geocoding: (lat: 34.41254, long: -119.84813)

Temporal Trends

(2) Spatio-Temporal Kernel Density

Estimation (STKDE)

n: the number of citations, hs and ht are the spatial and temporal bandwidths. ks and kt are kernel functions for multivariate probability density estimation withgiven bandwidths hs and ht

(2) Spatio-Temporal Kernel Density

Estimation (STKDE)

Spatio-Temporal Citation Mean Centers

e.g., Berners-Lee, T., Hendler, J., & Lassila, O. (2001). The semantic web. Scientific american, 284(5).

(3) Citation Cartogram

(4) Citation Distance Distributions

• Probability density functions (PDF)

• Cumulative distribution functions (CDF)

C(D) = Nc * Prob(D <= d)

we compare the pairwise citation at given distance intervals from CDFs and get the corresponding counts of citations, denoted as (Cp; dp), i.e., Cp citations occur within the pquantile distance dp.

(5) Spatial Point Pattern Analysis

• mean of citation-to-nearest-citation distance

(MC2NCD)

• average-nearest-neighbor-distance (ANND) index

complete spatial randomness (CSR)

Experiments

Categorical Places of Citations

Categorical Places of Citations

a*Nc1.71

b*Nc1.76

Individual Researchers

h-index (Hirsch, 2005)

h ≈ 12 might be a typical value for advancement to tenure

(associate professor)

h ≈ 18 might be a typical value for advancement to full

professor.

h ≈ 45 membership in the National Academy of Sciences

of the United States of America

Geospatial Index (s-index)

• A scientist has a geospatial-index s_country if s of his or her Np papers have been cited in at least s countries.

• A scientist has a geospatial-index s_city if s of his or her Np papers have been cited in at least sα

cities/towns.

• A scientist has a geospatial-index s_institution if s of his or her Np papers have been cited in at least sβ

institutions.

Conclusions and Future Work

• Provide an alternative way to explore the citation

impact of publications and researchers

• Citation Map REST Web Services for researchers

• Domain-based citation data analysis

Citation MapSTKO Citation Map, UC Santa Barbara

Thanks for your attention!

http://stko-work.geog.ucsb.edu:8080/map/