The research work in this thesis was divided into three phases; Analysis and design,
Prototype I, and Prototype II (depicted in Figure 2.2). The phases were executed in a
consecutive order. Lessons learned from the research conducted in the first phase
influenced the work in the second phase, etc. The objective of the first phase was to get
an overview of the current state-of-the-art constituting a basis for ideas. In the second
phase, the objective was to test those ideas and validate theories created in the first
phase by implementing a prototype and conducting an experiment with real users. The
objective of the third, and last phase, was to get further insight on the construction of
FVs. Therefore, we implemented a new FV construction (FVC) algorithm as part of the
second prototype. The FVC algorithms were validated by conducting controlled
laboratory experiments. For each of these phases a set of four tasks (i.e. a research
cycle) was executed in a consecutive order (depicted in Figure 2.2). The theoretical
framework is then revised for each new loop of the research cycle. The revision being
based on lessons learned from the previous loop of the cycle