International Journal of Geo-Information Review Global Research on Artificial Intelligence from 1990–2014: Spatially-Explicit Bibliometric Analysis Jiqiang Niu 1,*, Wenwu Tang 2,3, Feng Xu 1, Xiaoyan Zhou 4 and Yanan Song 4 1 School of Urban and Environmental Science, Xinyang Normal University, Xinyang 464000, China; [email protected] 2 Department of Geography and Earth Sciences, University of North Carolina at Charlotte, Charlotte, NC 28262, USA; [email protected] 3 Center for Applied Geographic Information Science, University of North Carolina at Charlotte, Charlotte, NC 28262, USA 4 School of Resource and Environmental Science, Wuhan University, Wuhan 430079, China; [email protected] (X.Z.); [email protected] (Y.S.) * Correspondence: [email protected]; Tel.: +86-188-3767-2366 Academic Editors: Kathleen Stewart, Alexander Klippel and Wolfgang Kainz Received: 5 February 2016; Accepted: 10 May 2016; Published: 16 May 2016 Abstract: In this article, we conducted the evaluation of artificial intelligence research from 1990–2014 by using bibliometric analysis. We introduced spatial analysis and social network analysis as geographic information retrieval methods for spatially-explicit bibliometric analysis. This study is based on the analysis of data obtained from database of the Science Citation Index Expanded (SCI-Expanded) and Conference Proceedings Citation Index-Science (CPCI-S). Our results revealed scientific outputs, subject categories and main journals, author productivity and geographic distribution, international productivity and collaboration, and hot issues and research trends. The growth of article outputs in artificial intelligence research has exploded since the 1990s, along with increasing collaboration, reference, and citations. Computer science and engineering were the most frequently-used subject categories in artificial intelligence studies. The top twenty productive authors are distributed in countries with a high investment of research and development. The United States has the highest number of top research institutions in artificial intelligence, producing most single-country and collaborative articles. Although there is more and more collaboration among institutions, cooperation, especially international ones, are not highly prevalent in artificial intelligence research as expected. The keyword analysis revealed interesting research preferences, confirmed that methods, models, and application are in the central position of artificial intelligence. Further, we found interesting related keywords with high co-occurrence frequencies, which have helped identify new models and application areas in recent years. Bibliometric analysis results from our study will greatly facilitate the understanding of the progress and trends in artificial intelligence, in particular, for those researchers interested in domain-specific AI-driven problem-solving. This will be of great assistance for the applications of AI in alternative fields in general and geographic information science, in particular. Keywords: Artificial Intelligence; bibliometric analysis; scientific outputs; research trends; SCI-expanded; Conference Proceedings Citation Index-Science 1. Introduction Artificial Intelligence (AI) is a subject that studies theories, methods, and applications with respect to simulation, extension, and expansion of human intelligence for problem-solving. Application domains of AI include robotics, voice recognition, image recognition, natural language processing, and ISPRS Int. J. Geo-Inf. 2016, 5, 66; doi:10.3390/ijgi5050066 www.mdpi.com/journal/ijgi ISPRS Int. J. Geo-Inf. 2016, 5, 66 2 of 18 ISPRS Int. J. Geo-Inf. 2016, 5, 66 2 of 19 essence of intelligence and design intelligent machines that can act as human behavior. AI has expertattracted systems researchers [1]. 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