Intelligent agents have become prevalent in everyday IT products and services. To improve an agent's knowledge of a user and the quality of personalized service experience, it is important for the agent to cooperate with the user (e.g., asking users to provide their information and feedback). However, few works inform how to support such user-agent co-performance from a human-centered perspective. To fill this gap, we devised Co-Performing Agent, a Wizard-of-Oz-based research probe of an agent that cooperates with a user to learn by helping users to have a partnership mindset. By incorporating the probe, we conducted a two-month exploratory study, aiming to understand how users experience co-performing with their agent over time. Based on the findings, this paper presents the factors that affected users' co-performing behaviors and discusses design implications for supporting constructive co-performance and building a resilient user-agent partnership over time.

Recently, self-tracking devices such as wearable activity trackers have become more available to end users. While these emerging products are imbued with new characteristics in terms of human-computer interaction, it is still unclear how to describe and design for user experience in such devices. In this paper, we present a three-week field study, which aimed to unfold users' experience with wearable activity trackers. Drawing from Knapp's model of interaction stages in interpersonal relationship development, we propose three stages of relationship development between users and self-tracking devices: initiation & experimentation, intensifying & integration, and stagnation & termination. We highlight the challenges in each stage and design opportunities for future self-tracking devices.

Recently, a great amount of conversation is taking place through mobile instant messaging (MIM) applications. The emergence of mobile messengers has enabled people to spend significant time in MIM, dwelling with close people. To investigate how this persistent use of MIM shaped the roles and meanings of MIM chatrooms, we conducted semi-structured interviews with ten users of KakaoTalk, one of the most popular MIM applications in South Korea. By understanding how participants determine the notion of centrality in MIM, we discovered three functional regions, namely, primary, secondary, and tertiary regions, which respectively support different functions not only in communication, but also in social interaction with various types of relationships: performing everyday life, connecting to the maintained social capital, and connecting to the expired relationship. Based on the valued meanings and user behaviors in those regions, we highlight two approaches that would trigger a new perspective in the design of messaging applications.

People worldwide are increasingly acquiring collections of virtual possessions. While virtual possessions have become ubiquitous, little work exists on how people value and form attachments to these things. To investigate, we conducted a study with 48 young adults from South Korea, Spain and the United States. The study probed on participants' perceived value of their virtual possessions as compared to their material things, and the comparative similarities and differences across cultures. Findings show that young adults live in unfinished spaces and that they often experience a sense of fragmentation when trying to integrate their virtual possessions into their lives. These findings point to several design opportunities, such as tools for life story-oriented archiving, and insights on better forms of Cloud storage.

In this paper, we suggest interactivity, which defines dynamic and invisible characteristics of an interactive system, as a medium for self-expression in an online communication environment. Since existing means of self-expression are visual- or text-oriented, they cover only a part of one's real self. Interactivity, however, is invisible, but still evokes emotional experiences depending on its value. Therefore, we expected that one's interactivity expression customization would also represent the different dimensions of one's characteristics. This study aims to explore the possibility of interactivity expressions as a new way of self-expression in an online communication environment. By conducting a user study with a social website prototype, namely, iSpace, in which each user's personal site can be distinguished by their different interactivity expressions, this study provides understandings of rationales and patterns of interactivity expressions, and design implications which we expect to inspire designers to consider them strategically in their design practices.

Statistical graphics on the web such as a tag cloud visually represent statistical data which are generated by website users. While sighted people can scan the latest information through the dynamic changes of statistical graphics, blind people, who cannot perceive them, lose opportunities to keep up to date in this quickly-changing society. In order to enable blind people to experience socially-generated statistical graphics, we propose a new assistive device, namely, Handscope, which translates statistical graphics on websites into simple height changes of its haptic pole. We conducted a two-phase user study with blind people in order to test its usability and explore its effects on the quality of blind users' web experiences. The results show the meaningful contribution of Handscope in extending the area of blind people's web experiences.