I wish to express my deepest gratitude to Academy Professor Teuvo Kohonen without whom this work would not have been possible. As the inventor of the Self-Organizing Map he has created this area, and as the leader of the Neural Networks Research Centre he has gathered a stimulating and effective environment. I wish to thank professor Kohonen for his most invaluable advice and fatherly personal encouragement. His support has covered an overwhelming expertise in the technical and methodological issues as well as in the philosophical underpinnings of the field. Without his efforts from the 1960's till these days the concentrated and well-equipped research would not have been possible.
As a member of the WEBSOM team I have received great help and support. Central parts of this work are based on this collaboration. Therefore, I wish to show my deepest gratitude to Dr.Tech. Samuel Kaski, Prof. Teuvo Kohonen, and Ms Krista Lagus. I also wish to thank former colleagues Dr.Tech. Ari M. Vepsäläinen and Mr. Ville Pulkki for their efforts, and all the current and former colleagues in the Neural Networks Research Centre and in the Laboratory for Information Processing Science of Helsinki University of Technology, in VTT Information Technology, in VTKK Tietopalvelu, in Kielikone project of Sitra foundation, and in the Department of Information Processing Science of University of Oulu.
I wish to thank the prereviewers Prof. Fred Karlsson and Prof. Pasi Koikka-lainen for their invaluable and constructive comments on the work and suggestions for improvements.
I have received a lot of valuable help, advice and comments during the years of research work from many current and former supervisors and colleagues, collaborators, and academic friends. I wish to express my warmest thanks to Ms Riitta Alkula, Dr. Harri Arnola, Mr. Jukka Honkela, Ms Sanna Hätönen, Dr. Heikki Hyötyniemi, Dr. Mauri Kaipainen, Dr. Jari Kangas, Prof. Fred Karlsson, Ms Taru Kuhanen, Mr. Aarno Lehtola, Prof. Seppo Linnainmaa, Dr. Kirsti Lonka, Ms Sini Maury, Prof. Erkki Oja, Ms Eeva Palosuo, Dr. Inga-Britt Persson, Mr. Jarno Raukko, Mr. Timo Sampolahti, and Prof. Olli Simula. I hope that the inevitable omissions will be forgiven.
Last but not least, I would like to thank Dr. Kaarlo Jaakkola and Dr. Jari Ahlberg as well as Shiatsu specialist Raija Koivisto for their efforts in ensuring my health recovery without which I would not have been able to write this thesis.
The thesis is dedicated to my parents: Maila, who left this world too early, Kaisa and Unto; and to Kristiina and Johanna whose patience I gratefully acknowledge; and especially to Catherine who has given me her understanding support and the deepest motivation for the work in its last phases.
I hope that this work provides insight into how it is possible to learn to understand, and, on the other hand, why it is not always easy to understand, although the same words are used. As a more straightforward consequence I also wish that the methodological results support development of applications that help people to communicate with each other efficiently by providing means for finding relevant information, and, in the long run, help in preventing unnecessary misunderstandings.