Forbidden Magnification? II.
Erzsébet Merényi, A. C. JAIN · 2004
Abstract. The twin of this paper, “Forbidden Magnification? I.” [1], presents systematic SOM simulations with the explicit magnification control scheme of Bauer, Der, and Herrmann [2] on data for which the theory does not guarantee success, namely data that are n-D, n> 2 and/or data whose components in the different dimensions are not statistically independent. For the unsupported n = 2 cases that we investigated the simulations show that even though the magnification exponent αachieved achieved by magnification control is not the same as the intended αintended, the direction and sign of αachieved systematically follows αintended with a more or less constant offset. We experimentally showed that for simple synthetic higher dimensional data negative magnification has the desired effect of improving the detectability of rare classes. In this paper we study further theoretically unsupported cases, including experiments with real data. 1 Known limits of SOM magnification control