Usability evaluation of touch panel-based mobile device on user interface with multimodal feedback

We conduct a study to evaluate the user-friendliness of compact input device on multimodal interface. The interface provides visual and auditory feedback while the tactile feedback generated by the rolling unit attached to the Compact input device. Based on these interfaces, a set of experiments is conducted to compare their efficiencies. The measurement criteria used in this experiment are number of characters inputted, the operational time for the task in seconds, and opinion in term of understandability and comfort ability towards settings of the combination of the user interfaces in discrete indices. The experimental results show that with the proper combination of feedback interfaces for the user, the efficiency can be improved by either the reduction in operational time or the increase of accuracy in text inputting. The appropriateness of the combination of interfaces is also justified with the user's satisfaction towards using the device to conduct the predefined text-inputting task.