A Scientometrics Study of Rough Sets in Three Decades JingTao Yao and Yan Zhang Department of Computer Science University of Regina [jtyao, zhang83y]@cs.uregina.ca Oct. 8, 2013
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 2/22 Introduction of Rough Sets proposed by Professor Zdzis law Pawlak in the early 1980s. a mathematical approach dealing with inconsistent and uncertain data. approximate a concept in terms of a pair of sets which give the lower and the upper approximation of the concept. be in a state of constant development over three decades. three approaches in rough set research: content based approach, method based approach, scientometric approach.
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 3/22 Scientometrics Method Scientometrics is the science that measures and analyzes science. We may gain more understanding of a research domain by examining its publications. Research impact may be measured by citations. Citation may be used as a bibliometric indicator to predict research influences and development. The more recent or current highly cited papers in a research field, the more likely the field will grow rapidly in the near future.
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 4/22 Web of Science Web of Science (WoS) is one of Thomson Reuters s key products. http://thomson-reuters.com/web-of-science/ WoS collects bibliographic information of research articles of high quality journals and selected international conferences. The database collects not only bibliographic information but also the information of citation relationship amongst research articles.
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 5/22 Search in Web of Science A rough set paper: containing phrase rough sets or rough set or rough computing or rough computation. The Topic field is defined as the words or phrases within article titles, keywords, or abstracts. Not all rough set publications are included in the search, e.g., Transactions on Rough Sets.
Rough Set papers published in three decades 1 0 0 0 9 0 0 8 0 0 N u m b e r o f P a p e rs 7 0 0 6 0 0 5 0 0 4 0 0 3 0 0 2 0 0 1 0 0 0 1 9 8 2 1 9 8 5 1 9 8 6 1 9 8 7 1 9 8 8 1 9 8 9 1 9 9 0 1 9 9 1 1 9 9 2 1 9 9 3 1 9 9 4 1 9 9 5 1 9 9 6 1 9 9 7 1 9 9 8 1 9 9 9 P u b lic a tio n Y e a r 2 0 0 0 2 0 0 1 2 0 0 2 2 0 0 3 2 0 0 4 2 0 0 5 2 0 0 6 2 0 0 7 2 0 0 8 2 0 0 9 2 0 1 0 2 0 1 1 2 0 1 2 2 0 1 3 J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 6/22
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 7/22 Most prolific authors Table: Most prolific authors Authors Papers Authors Papers Authors Papers Slowinski R 92 Hu QH 58 Grzymala-busse JW 43 Skowron A 91 Pal SK 57 Ramanna S 43 Yao YY 83 Miao DQ 55 Wang J 42 Wang GY 74 Chen DG 52 Polkowski L 41 Peters JF 72 Slezak D 52 Suraj Z 41 Wu WZ 70 Qian YH 48 Zhu W 40 Zhang WX 68 Li TR 47 Pawlak Z 39 Tsumoto S 67 Yu DR 46 Shi KQ 39 Greco S 66 Lin TY 44 Cheng CH 38 Liang JY 59 Ziarko W 44 Jensen R 37
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 8/22 Top 15 countries or territories Table: Top 15 countries or territories Countries Papers Countries Papers Countries Papers P. R. China 3741 India 290 Wales 67 Poland 660 Taiwan 286 Iran 64 USA 440 Italy 120 South Korea 62 Canada 428 England 91 Germany 61 Japan 356 Malaysia 76 Spain 59
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 9/22 Top 15 institutions Table: Top 15 institutions Organizations Papers Organizations Papers Univ Regina 177 Zhejiang Univ 87 N China Elect Power Univ 154 Zhejiang Ocean Univ 80 Chinese Acad Sci 132 Shanghai Jiaotong Univ 74 Polish Acad Sci 117 Univ Manitoba 74 Harbin Inst Technol 116 Tongji Univ 73 Xian Jiaotong Univ 106 Indian Stat Inst 68 SW Jiaotong Univ 99 Polish Japanese Inst Infor Technol 68 Warsaw Univ 93
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 10/22 Top 10 journals including rough set articles Table: Top 10 journals Journals Papers Information Sciences 230 Fundamenta Informaticae 160 Expert Systems with Applications 135 Advanced Materials Research 100 International Journal of Approximate Reasoning 83 Knowledge Based Systems 78 Applied Mechanics and Materials 65 European Journal of Operational Research 52 Fuzzy Sets and Systems 52 Computers Mathematics with Applications 41
Citation each year 7 0 0 0 6 0 0 0 5 0 0 0 C ita tio n s 4 0 0 0 3 0 0 0 2 0 0 0 1 0 0 0 0 1 9 8 4 1 9 8 5 1 9 8 6 1 9 8 7 1 9 8 8 1 9 8 9 1 9 9 0 1 9 9 1 1 9 9 2 1 9 9 3 1 9 9 4 1 9 9 5 1 9 9 6 1 9 9 7 1 9 9 8 1 9 9 9 2 0 0 0 Y e a r 2 0 0 1 2 0 0 2 2 0 0 3 2 0 0 4 2 0 0 5 2 0 0 6 2 0 0 7 2 0 0 8 2 0 0 9 2 0 1 0 2 0 1 1 2 0 1 2 2 0 1 3 J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 11/22
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 12/22 Top 20 cited papers Table: Top 20 cited papers Paper Total Average Main Results Citations per Year 1 Pawlak 1982 3694 115.44 Seminal paper, proposed RS 2 Ziarko 1993 659 31.38 Variable precision RS 3 Dubois+ 1990 565 23.54 Combining with fuzzy sets 4 Pawlak+ 2007 495 70.71 RS survey 5 Kryszkiewicz 1998 386 24.12 App - imcompete information table 6 Greco+ 2001 372 28.62 App - decision analysis 7 Pawlak+ 1995 352 18.53 Basic theory of RS 8 Slowinski+ 2000 323 23.07 Generalized RS 9 Pawlak+ 2007 315 45.00 RS survey 10 Mitra+ 2000 304 21.71 RS survey 11 Pawlak+ 2007 275 39.29 RS survey 12 Yao YY 1998 267 16.69 Research methods in RS 13 Kryszkiewicz 1999 249 16.60 App - imcompete information table 14 Yao YY 1998 236 14.75 Generalized RS using binary relation 15 Swiniarski+ 2003 231 21.00 App - feature selection 16 Pawlak 1998 231 14.40 App - data analysis 17 Yao YY 1996 219 12.17 Interpretation of RS 18 Wu WZ+ 2003 205 18.64 Combining with fuzzy sets 19 Pawlak 2002 198 16.50 App - data analysis 20 Polkowski+ 1996 194 10.78 Basic theory of RS
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 13/22 Classification of papers In top 20 cited papers, twelve papers are about basic rough set theory and generalized rough sets, two papers are about combining rough sets with other theories, six papers are about applications of rough sets. In top 200 cited papers, applications of rough sets and combination with other theories account for 27% and 49.5%. The number of papers about applications of rough sets in different areas are constantly increasing.
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 14/22 Impact authors Table: Impact authors Authors Cites cts Authors Cites cts Pawlak Z 5957 10 Jensen R 548 5 Slowinski R 1689 8 Mi JS 545 4 Skowron A 1510 5 Shen Q 544 5 Yao YY 1456 10 Mitra S 520 3 Ziarko W 1088 3 Zhu W 474 4 Zhang WX 798 6 Grzymalabusse J 458 2 Greco S 758 4 Hu QH 407 3 Matarazzo B 758 4 Pal SK 392 4 Kryszkiewicz M 749 3 Vanderpooten D 323 1 Wu WZ 737 6 Zopounidis C 312 2 Dubios D 641 2 Yu DR 305 3 Prade H 641 2 Hayashi Y 304 1
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 15/22 Top 20 cited papers in recent 5 years Table: Top 20 cited papers in recent 5 years Paper Total Average Main Results Citations per Year 1 Feng F+ 2008 91 15.17 Soft sets 2 Yao YY+ 2008 81 13.50 Reduction in DTRS 3 Yao YY 2008 76 12.67 Probabilistic rough sets 4 Hu QH+ 2008 75 12.50 App - feature subset selection 5 Zhu W 2009 69 13.80 Generalized RS 6 Hu QH+ 2008 65 10.83 App - neighborhood classifier 7 Jensen+ 2009 64 12.80 App - feature selection 8 Wu WZ 2008 60 10.00 Attribute reduction 9 Qian YH+ 2010 55 13.75 Reduction accelerator 10 Wang XZ+ 2008 52 8.67 App - rule induction 11 Thangavel+ 2009 48 9.60 Reduction (survey) 12 Liu GL 2008 48 8.00 Generalized RS 13 Qian YH+ 2008 48 8.00 Measures 14 Yang XB+ 2008 45 7.50 Dominance RS 15 Feng F+ 2010 44 11.00 Soft sets 16 Yao YY 2010 41 10.25 Introduced three-way decision 17 Xiao Z+ 2009 41 8.20 App - forecasting 18 Bai CG+ 2010 38 9.50 Combining with grey system 19 Li H+ 2008 38 6.33 App - prediction 20 Feng F+ 2011 37 12.33 Soft sets
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 16/22 Classification of papers In top 20 cited papers in recent 5 years, eight papers are about basic rough set theory and generalized rough sets, five papers are about combining rough sets with other theories, seven papers are about applications of rough sets. There are many new and young researchers, many of them from China, contributed to the highly cited papers in recent five year. Most of highly cited papers in last five years are extensions and applications of existing research, compared with top 20 cited papers in three decades. The theory of three-way decisions, motivated by rough set three-regions but goes beyond rough sets, is a promising research direction that may lead to new breakthrough.
Inspec Table: Number of papers published each year (Inspec) Year 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 Papers 1 1 4 6 10 10 12 14 11 14 23 Year 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Papers 30 105 49 117 70 186 138 150 185 329 360 Year 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Papers 415 525 693 922 1236 1331 1346 993 759 44 1 6 0 0 1 4 0 0 1 2 0 0 N u m b e r o f P a p e rs 1 0 0 0 8 0 0 6 0 0 4 0 0 2 0 0 0 1 9 8 4 1 9 8 6 1 9 8 8 1 9 9 0 1 9 9 2 1 9 9 4 1 9 9 6 1 9 9 8 P u b lic a tio n Y e a r J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 17/22 2 0 0 0 2 0 0 2 2 0 0 4 2 0 0 6 2 0 0 8 2 0 1 0 2 0 1 2 2 0 1 4
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 18/22 IEEE Digital Library Table: Number of papers published each year (IEEE) Year 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 Papers 2 2 2 5 18 7 11 16 20 34 61 Year 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Papers 43 84 119 234 248 427 507 568 277 253 26 6 0 0 5 0 0 N u m b e r o f P a p e rs 4 0 0 3 0 0 2 0 0 1 0 0 0 1 9 9 2 1 9 9 4 1 9 9 6 1 9 9 8 2 0 0 0 2 0 0 2 2 0 0 4 2 0 0 6 2 0 0 8 2 0 1 0 2 0 1 2 2 0 1 4 P u b lic a tio n Y e a r
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 19/22 Developments of Rough sets 1 Rough set theory can be considered as an independent discipline. Probabilistic Rough Sets Decision-Theoretic Rough Sets Game-Theoretic Rough Sets Bayesian Rough Sets Information Theoretic Rough Set Approach Variable Precision Rough Sets Parameterized Rough Sets Dominance-based Rough Ret Approach 2 Generalized Rough Sets from three directions: binary relation based rough sets covering based rough sets subsystem based rough sets
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 20/22 Developments of Rough sets (continue) 3 Rough set theory has been combined with other theories, Fuzzy Sets Granular Computing The theoty of Three-way Decision Neural Network 4 Rough set applications, data analysis feature selection decision making (rules mining) incomplete information system multi-criteria decision analysis
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 21/22 Conclusion The analyses were conducted with other databases, IEEE Digital Library, Google scholar, and Inspec. The results more or less confirm with findings reported here. Rough sets has been in a state of constant development. Applying rough sets to different areas become more important. In order to broaden and deepen the study of rough sets, combining rough sets with other theories should be emphasized.
J. T. Yao & Y. Zhang A Scientometrics Study of Rough Sets in Three Decades 22/22 Questions?