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Asymmetric von Mises Scaling. SHOJIMA Kojiro The National Center for University Entrance Examinations shojima@rd.dnc.ac.jp. Purpose of Research. Development of an asymmetric multidimensional scaling (MDS) method using a technique from directional statistics
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Asymmetric von Mises Scaling SHOJIMA Kojiro The National Center for University Entrance Examinations shojima@rd.dnc.ac.jp
Purpose of Research • Development of an asymmetric multidimensional scaling (MDS) method using a technique from directional statistics • Asymmetric von Misesscaling (AMISESCAL)
Directional Statistics (c.f., Mardia & Jupp, 2000) • A branch of statistics dealing with angles, courses, and directions as data • Magnetic field analysis, animalmigration, disease transmission route, etc.
Slider von Mises distribution • Normal distribution in directional statistics μ: mean direction κ: concentration
Model ||xi-xj|| xj δij θji Person j μj κj κi μi xi Person i πji=f(θji|μj, κj) θij πij=f(θij|μi,κi) 1 5
Stress Function • Optimization • 1st Stage: Genetic Algorithm (GA) • 2nd Stage: Steepest Descent Method (SDM)
7 7 7 7 7 1 1 1 7 7 7 1 1 1 1 1 7 7 7 7 1 1 1 1 7 7 1 1 1 1 B C C A D A D B A C B
Omnidirectionality and the Amount ofOne-sided Love Omnidirectional and more love Omnidirectional and less love Reduces to the conventional von Mises distribution when ω=1/(2π)
Problem xj δij Person j xi πij=f(θij|μi,κi) Person i 1 5
Stress Function (2) • Adding Penalty Function U • Reward when there are one-sided love targets in the direction of heavy density • Penalty when there is no target in the direction of heavy density • Optimization • GA+SDM
Result 7 7 7 7 C C 1 1 7 1 1 7 1 1 D A A D B B
Future Tasks • Dealing with diagonal elements • Expansion to 3D model space • Expansion to 2 mode (multi-group or longitudinal) data Thank you for your attention. Kojiro Shojima (shojima@rd.dnc.ac.jp)