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Keränen H (2001)
A mobile retrieval user interface for heterogeneous multimedia document bases.
M.Sc. thesis, Department of Electrical Engineering, University of Oulu, Finland (in Finnish).

This thesis studies the suitability of existing retrieval user interface solutions for multimedia retrieval and proposes a paper prototype of a multimedia retrieval user interface for mobile terminals. The thesis reviews the essence of multimedia and the criteria that users want to search different types of media with. People usually want to search raw media, such as photographs, by their context information. When editing raw media for a multimedia presentation, the context information of the raw media normally transforms into the content information of the multimedia presentation. Thus content is the most important search target in multimedia presentations. In this thesis, retrieval user interface solutions are divided into browsing interfaces and query interfaces. Simple one- or two-dimensional visualisation techniques work best when exploring document space on the small screen of mobile terminal devices. Summaries of multimedia documents speed up the browsing and make it easier. Also advancements in positioning technologies bring new possibilities to searching multimedia. The existing query user interfaces are not ideal for multimedia retrieval. This thesis studies the different metaphors and different views in query definition, but problems arise especially in accommodating Boolean logic to queries. To solve these problems, this thesis presents a novel graphical query language. It also reviews different possibilities for presenting query results and techniques supporting the search process. In addition, a paper prototype of a multimedia retrieval user interface for mobile devices is created by using user-centred design. The user interface is designed especially to match the needs of a mobile journalist. The paper prototype showed that it is possible to construct the retrieval system, and the user interface was successfully designed for a small screen.