The present aim was to study the preference of tactile feedback stimulations given by non-physical (i.e., solid) piezo-actuated buttons. Participants (n=16) ranked 16 different tactile feedback stimuli varied by 4 output delays and 4 vibration durations. The results showed that the mean ranks of the stimuli differed significantly from each other. The timing parameters of delay and duration interacted with each other, for example, so that preference of certain vibration duration fluctuated in response to different output delays. Using a very short time window (i.e., 10-453 ms) combining both delay and duration parameters of the feedback could result either in favorable or significantly less favorable subjective experience. The results suggest that a preferred perception of tactile feedback from non-physical buttons requires careful design and controlling of the timing parameters.

The present aim was to study if thermal stimuli presented to the palm can affect emotional responses when measured with emotion related subjective rating scales and changes in skin conductance response (SCR). Two target temperatures, cold and warm, were created by either decreasing or increasing the temperature of the stimulus 4 °C in respect to the participants current hand temperature. Both cold and warm stimuli were presented by using two presentation methods, i.e., dynamic and pre-adjusted. The results showed that both the dynamic and pre-adjusted warm stimuli elevated the ratings of arousal and dominance. In addition, the pre-adjusted warm and cold stimuli elevated the SCR. The results suggest that especially pre-adjusted warm stimuli can be seen as effective in activating the autonomic nervous system and arousal and dominance dimensions of the affective rating space.

Cutaneous saltation provides interesting possibilities for applications. An illusion of vibrotactile mediolateral movement was elicited to a left dorsal forearm to investigate emotional (i.e., pleasantness) and cognitive (i.e., continuity) experiences to vibrotactile stimulation. Twelve participants were presented with nine saltatory stimuli delivered to a linearly aligned row of three vibrotactile actuators separated by 70 mm in distance. The stimuli were composed of three temporal parameters of 12, 24 and 48 ms for both burst duration and inter-burst interval to form all nine possible uniform pairs. First, the stimuli were ranked by the participants using a special three-step procedure. Second, the participants rated the stimuli using two nine-point bipolar scales measuring the pleasantness and continuity of each stimulus, separately. The results showed especially the interval between two successive bursts was a significant factor for saltation. Moreover, the temporal parameters seemed to affect more the experienced continuity of the stimuli compared to pleasantness. These findings encourage us to continue to further study the saltation and the effect of different parameters for subjective experience.

A prototype of friction-based horizontally rotating fingertip stimulator was used to investigate emotional experiences and behavioral responses to haptic stimulation. The rotation style of 12 different stimuli was varied by burst length (i.e., 20, 50, 100 ms), continuity (i.e., continuous and discontinuous), and direction (e.g., forward and backward). Using these stimuli 528 stimulus pairs were presented to 12 subjects who were to distinguish if stimuli in each pair were the same or different. Then they rated the stimuli using four scales measuring the pleasantness, arousal, approachability, and dominance qualities of the 12 stimuli. The results showed that continuous forward-backward rotating stimuli were rated as significantly more unpleasant, arousing, avoidable, and dominating than other types of stimulations (e.g., discontinuous forward rotation). The reaction times to these stimuli were significantly faster than reaction times to discontinuous forward and backward rotating stimuli. The results clearly suggest that even simple haptic stimulation can carry emotional information. The results can be utilized when making use of haptics in human-technology interaction.

Haptic stimulation in motion has been studied only little earlier. To provide guidance for designing haptic interfaces for mobile use we carried out an initial experiment using C-2 actuators. 16 participants attended in the experiment to find out whether there is a difference in perceiving low-amplitude vibrotactile stimuli when exposed to minimal and moderate physical exertion. A stationary bike was used to control the exertion. Four body locations (wrist, leg, chest and back), two stimulus durations (1000 ms and 2000 ms) and two motion conditions with the stationary bicycle (still and moderate pedaling) were applied. It was found that cycling had significant effect on both the perception accuracy and the reaction times with selected stimuli. Stimulus amplitudes used in this experiment can be used to help haptic design for mobile users.

As structured graphs are widely used in various application areas for conceptual modeling, the need for interactive layout adjusting methods is clearly recognized in the domain of graph drawing applications. We present a graph manipulation method where the process of adjusting and manipulating graphs is broken down into a group of direct and interactive tools. The tools are visualized as large tool-specific mouse cursors that are easily adjustable. Colors and highlighting are used to identify different tools and their operating ranges. According to the usability studies, the tools proved to be reasonably easy to use with only a short introductory time. The users could also select appropriate tools for each manipulation task without problems and were satisfied with the functionality as well as the visualization of the tools. The usefulness of the tools in manipulating graph drawings was also recognized.