**5. Conclusion and future works**

In this study, the subjects' ability to identify the location and direction of acoustic spatial sequences and follow it was evaluated through three experiments to discuss the practicality and feasibility of the proposed evacuation guidance systems.

In the first and second experiments, the accuracy rate and response time of subjects for identification the different sequences of sound stimuli were compared among several experimental conditions combining factors: the stimulus the type, emission interval, the distance between loudspeakers, and the sequence patterns. In the first experiment, the accuracy rates improved when the voice stimulus was used and when the emission-time interval was extended. Additionally, it was confirmed that the identification performance becomes better as the distance from the position of subject gets shorter.

In the second experiment, we observed no significant difference in the accuracy rates and response times for different sequence patterns (straight line and rightangle) under the experimental conditions.

In the third experiment the ability of people to follow the sequences of the emitting sound was evaluated based on the success rate and the required time to do so. The three experimental factors were considered, which were the stimulus type, the type of loudspeaker, and complexity of the sequence measured by number of turning points on it. In the third experiment, people took more time but could follow the sequences of emitting sound, which included five turning points. The required time is shorter in using the dynamic speaker than the capacitor flat speaker. This result suggests that subjects can perform sound localization for a sequence of the sounds emitting on dynamic speakers more easily than the capacitor flat one.

The results of this study demonstrate the practicality of an evacuation guidance system using a sound sequence that emits specific sounds on a set of loudspeakers. The factors affecting the performance of subject's identification of the acoustic stimuli were examined and analyzed, but the level of factors dealt with was limited such as the frequency change region of the swept-sound. Therefore, a more detailed analysis of the degree of influence of each factor is needed in the practical application of the proposed guidance stem for further studies.
