While dynamic difficulty adjustment techniques can enhance the player engagement, overly apparent difficulty adjustments may have a detrimental effect on the overall gaming experience. Hence, it is desirable to implement game difficulty controls as unnoticeable as possible. We interpret this issue as a research question: Is it possible to reduce the objective difficulty of a game without influencing the subjective difficulty that players perceive?, and propose two techniques for dynamically adjusting game difficulty that is imperceptible to players: Collision Detection Area Adjustment and Time Elapse Manipulation. We integrated these two techniques into a simple shoot’em up game and evaluated their effectiveness through a user study. The results support the claim that these difficulty adjustment techniques can reduce the objective difficulty of a game without influencing the subjective difficulty that players perceive. This study could be beneficial, not just as a rare example in the research in difficulty adjustment that distinguishes objective difficulty and subjective difficulty, but also as a practical technique for difficulty adjustment that can avoid the negative impact on the gaming experience.

Picture books are considered beneficial for children in many ways (e.g., psychological development and language acquisition), yet some children have less opportunity to receive such benefits because of their visual impairment. Considering such a situation, we designed Alice and Her Friend, an interactive book for visually-impaired children. While we put a significant focus on multisensory interaction, the book is designed entirely in black, intending both to emphasize that visually-impaired people also enjoy rich multisensory experiences and to raises awareness of the needs that visually-impaired children have. We used the book to interview experts in related fields to investigate practical needs among visually-impaired children. Based on their insights, we also propose a novel research topic, "creative technologies for the disabled"; it is necessary to support people with disabilities to create what they need by themselves, since the degrees and types of visual impairment significantly differ among visually-impaired people.

We developed a novel marker tracking method with shape-free designable markers, which can be visually meaningful to users. The method can work fast enough to provide a real-time camerabased interaction even on low performance CPUs such as one used in mobile Internet devices. Features such as visually communicative design and inexpensive computational cost are very desirable for users with mobile devices in the mobile/pervasive interaction environment. The method utilizes the topological region adjacency to detect the marker candidates and then apply a simple method similar to geometric-hashing to determine the detected maker by voting to the hash tables. By such a combination of two different approaches, our method can distinguish those markers with the same topological structure and is also capable of 6-DoF post estimation whereas most of the existing topology-based systems can not distinguish markers with the same topological.

In this paper, we describe a new method for camera-based fiducial tracking. Our new method is based on the combination of topological region adjacency and angle information, where as related works by Johnston's RAG target [7], Costanza's D-Touch [3], and Kaltenbrunner's reacTIVision [2] are based on the uniqueness of the topological region adjacency structure.

Tre Marie is an interactive audio-visual dance improvised performance. The system in progress is a RF-ID (radio-frequency identification) technology for dance performance, which improvises, live visuals on stage. The performance is a reconstructed architecture of space that encodes the spatial aesthetics of the interaction between human, theatrical and cinematic space.