Emotion in user interface, voice interaction system. - Vlaho Kostov; Shuichi Fukuda (SMC, 2000)

Cellular phone ringing tone recommendation system based on collaborative filtering method. - Vlaho Kostov; Eiichi Naito; Jun Ozawa (CIRA, 2003)

Analysis of Wearable Interface Factors for Appropriate Information Notification. - Vlaho Kostov; Jun Ozawa; Satoshi Matsuura (ISWC, 2004)

Platform for timely portable-push information delivery. - Vlaho Kostov; Jun Ozawa; Eiichi Naito (CCNC, 2006)

Analysis of Appropriate Timing for Information Notification Based on Indoor User's Location Transition. - Vlaho Kostov; Takashi Tajima; Eiichi Naito; Jun Ozawa (PerCom, 2006)

Evaluation of Appropriate Body Placement and Notification Modality of a Wearable Clip-on Notifier Using an Experimental Platform. - Vlaho Kostov; Eiichi Naito; Takashi Tajima; Jun Ozawa (J. Adv. Comput. Intell. Intell. Informatics, 2007)