Publication 1 deals with the monitoring and exploration of EEG waveforms. Here the other authors were primarily responsible for the medical aspects and implications of the study. The methodology related to preprocessing, computation of the maps, and visualization of the results was mainly the responsibility of the author of the thesis.
In Publication 2 the idea of computing the taxonomies of countries with the SOM based on socioeconomic data, as well as valuable guidance and contributions to the writing of the article are credited to Professor Teuvo Kohonen. The author of the thesis designed and conducted the practical part of the study.
Studies on the WEBSOM full-text document analysis method are described in Publications 3, 4, 5, and 6. The basic system is presented in Publication 3, subsequently developed vast maps in Publication 4, and the exploration interface and suggested ways of using it in Publication 5. The original idea of using a two-stage SOM architecture for organizing document collections was due to Mr. Timo Honkela, and the methods for producing huge SOMs efficiently (presented in Publication 4) were originated by Professor Kohonen. Most other ideas and details, and the implementation and the experiments were developed jointly as a team, and it is not possible to give a full account of all of the differences in the contributions of the team members. The ideas that are predominantly due to the author of the thesis are the efficient encoding of the documents by table lookups and a subsequent convolution, analyzed in detail in Publication 6, and the entropy-based weighting of the words in computing word category histograms (described in Publication 4).
New procedures for comparing self-organized maps were introduced in Publication 7. The realization of the potential importance of comparing maps without judging their relative goodness was due to Ms Krista Lagus. Professor Kohonen should also be credited for valuable discussions related to comparing SOMs. The idea of the presented goodness measure as well as the design of the measures and the experiments was predominantly due to the author of the thesis.
In Publication 8 the ASSOM architecture conceived by Professor Kohonen [Kohonen, 1995a, Kohonen, 1995b, Kohonen, 1995c, Kohonen, 1996] is described, and a set of experiments made to demonstrate its capabilities is reported in detail. The theoretical aspects of the ASSOM, some minor details notwithstanding, are due to Professor Kohonen. The contributions of the author of the thesis are the joint development of the mathematical analysis part of the Publication with Professor Kohonen, and the joint conduction of the experiments with Mr. Harri Lappalainen.