People of ACM - Koji Yatani

November 5, 2020

Why is this an exciting time to be working at the intersection of human-computer interaction and ubiquitous computing?

My group is driving application-oriented research through novel interactive systems. It is always exciting to work in human-computer interaction (HCI) and ubiquitous computing as they are the best places to discuss applications on emerging information technologies. Research on applications touches on many exciting challenges. Besides technical improvements, we need to understand what practices and problems people currently have, and how we can design technology to better fit their activities. Application-oriented thinking enables researchers to develop a capability to obtain a comprehensive perspective on both technology and humans in addition to skills to drive technical breakthroughs.

I am also always fascinated by the diversity of research I witness in HCI and ubiquitous computing. ACM UbiComp is one of my favorite conferences, where I am impressed by very strong technical work as well as investigations on the user experience of novel information technology in real life. When I joined the University of Tokyo, I was determined that I would lead a laboratory where students are working on a variety of cool projects that span multiple research topics instead of a group where all projects simply fit under a single umbrella. This decision was really a big challenge to me (and still is!) because I often need to go outside my comfort zone, but this life always leads me to new knowledge and interests, and it is a luxury in my life.

Will you tell us what you mean by “creativity and productivity support,” and give an example of an application you worked on in this area?

It was a great honor for me to receive the IPSJ/ACM Award for Early Career Contributions to Global Research for productivity support through mobile applications. Much of the work was done in collaboration with wonderful colleagues and interns when I worked at Microsoft Research Asia. For example, Darren Edge and I worked on a variety of interactive systems to support presentation activities, from creating slides to delivery. TalkZones is one great example of our research outcomes, a mobile interface to support presenters to keep to their allotted presentation time as well as flexibility to adjust when talks are running over/under their allotted time.

Another instance is decision making support through mobile applications. As smartphones have become commodity devices, users now frequently perform information collection and decision making on those devices. We created ReviewCollage, which allows users to compare two entities in online review websites (e.g., restaurants and products) through a collection of visualizations. Our system can be most useful when the entities to compare are similar because it can highlight the differences in the visualizations.

For creativity support, we have worked mostly on supporting artistic expressions in different media, such as drawing and music performance. For example, we have developed interactive drawing support through auto-completion mechanisms ( and With such systems, users can focus on their expressions without needing to perform repetitive manipulations. We are currently working on interactive support for music and dance activities, and I hope we can share these exciting results soon.

What is an exciting project that you and your team are working on now at the University of Tokyo’s Interactive Intelligent Systems Laboratory?

Recently, we have started several projects on usable security. In one of the projects, we investigated how nudges can influence adolescent users’ intentions on social networking services (SNS). We conducted a large-scale survey with adolescent SNS users (self-identified high school and university students). We collected approximately 30,000 responses about their intended actions in nine scenarios with different designs of nudges displayed. The interfaces with nudges are very simple; they just include one sentence of “warnings,” but it can influence people’s decisions. The results are intriguing. We found that participants were more likely to avoid potentially risky choices when presented with negative frames (e.g., “90% of users would not share a photo without permission”) than affirmative ones (e.g., “10% of users would”). We also revealed that nudges with general suggestions or negative social nudges could be effective in scenarios where there is a 50/50 chance for participants to choose a risky action.

In addition to such quantitative investigations, we are also working on creating additional value in security systems. We have proposed the concept of dual-purpose biometrics, biometrics authentication systems that enable concurrent physiological or behavioral sensing. Such extracted data can enrich existing health-related applications while users would still simply perform authentication (e.g., unlocking a smartphone with their fingerprints). We have created a photoplethysmography-sensing mechanism in fingerprint authentication on smartphones as an example of dual-purpose biometrics, and we are currently working hard to further expand our concept.

What is an example of an emerging AI application that will have broad impact on IoT systems in the coming years?

People’s lifestyles often change drastically. Remote/distributed working styles triggered by COVID-19 are one recent example we have seen. It is amazing to see how people manage to adapt to new lifestyles through technology while new issues arise, such as socialization in online communication media. I believe that people’s lifestyles will be further diversified, and “one-size-fits-all” designs and services will not fit emerging lifestyles. As HCI researchers, we should investigate and understand people’s diverse activities and lifestyles more deeply, and AI and IoT are critical to making it happen. Findings from such studies should lead us to the creative use of technology to enable novel applications. Or it may highlight potential risks and threats, which we should warn society about before they become real. As an HCI researcher, it is exciting to leverage the power of emerging information technology infrastructures to illustrate the future through novel applications—and our work at the IIS Lab demonstrates this.

Koji Yatani is an Associate Professor and 2017 UTokyo Excellent Young Researcher at the University of Tokyo, where he leads the Interactive Intelligent Systems Laboratory (IIS Lab). His research interests lie in human-computer interaction (HCI) and ubiquitous computing, focusing on novel applications of emerging information infrastructure, such as AI and IoT systems. Some of his recent research topics include creativity and productivity support, sensing technologies for personal healthcare, and usable security.

Yatani was one of the founding editors of Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies (PACM IMWUT). His volunteer roles also include serving as the Vice Chair of the ACM Japan SIGCHI Chapter and the Steering Committee Chair for the annual ACM UbiComp conference. Yatani’s honors include receiving the Research Institute of Electrical Communication (RIEC) Award from Tohoku University, and the Information Processing Society of Japan (IPSJ)/ACM Award for Early Career Contributions to Global Research.