Originated from the theories of fuzzy logic, neural networks, soft computing and computational intelligence techniques, Fuzzy Cognitive Maps (FCMs) can be understood as a modeling methodology based on exploiting knowledge and experience. In general, FCMs belong to the granular computing field, which refers to the conceptualization/processing of information granules (i.e., concepts). At the same time, FCMs can model causal relationships in complex systems that evolve with time.
Figure 1(a) illustrates the interface of the developed FCM-Viewer application. As it can be seen from the latter, a series of user-selection categories is available. In particular, the requirement for the FCM-Viewer to function is the loading of the concept interconnection weights matrix. This could be realized in two ways, i.e., either from a Matlab format (.mat) file or as a variable from the Matlab workspace. As soon as the weights matrix is loaded, a series of concept layout parameters becomes available. With the navigation buttons (PREVIOUS-NEXT-GO TO), the user could navigate to each concept and alter/save its characteristics or use the defaults button that directly corresponds the default values to all variables. Moreover, the user could set the weights layout, select the FCM layout type, enable/disable nodes auto size, set the scaling factor (values greater (smaller) than 1 shrink (expand) the FCM representation), select the arrows characteristics and the weights layout. Via the HELP button, a help video is automatically triggered that visually explains all the functionalities of the FCM-Viewer.
When the aforementioned parameters are set, the FCM could be created and visualized in a new window (Figure 1(b)) with available menu functionalities of saving, exporting, moving, zoom in/out, and node right-click functionalities, such as highlighting of the ancestors/descendants or both, along with the node properties. The visualized FCM could also be exported as a visual object handle and loaded again as a separate object (see Figure 1(a)-bottom), to facilitate the easy access to existing FCMs.
It should be noted that the FCM-Viewer requires prior installation of the Matlab Bioinformatics Toolbox; hence, with the initiation of the FCM-Viewer application, the user is automatically informed about the existence or not of the specific toolbox in the currently running Matalb version (>R2011 version is preferable). Finally, a mouse-over help is available for each button of the FCM-Viewer, whereas a series of warnings/information messages or returns to previous states is evoked when a wrong selection is performed by the user.
It should be noted that FCM-Viewer is freely available upon request.