Ryosei Kojima

小嶋 凌勢

Ph.D. Student, Degree Program in Informatics
Digital Nature Group (Yoichi Ochiai Lab), University of Tsukuba

Non-contact Haptic Display Using Air Vortex Rings

Ryosei Kojima

About

5+ years of R&D experience leading award-winning air-vortex systems for accessibility and contributing to HIFU-based tactile interfaces. End-to-end engineering expertise from theoretical design to practical implementation, with societal impact in accessibility and HCI. Co-authored paper on HIFU Embossment of Acrylic Sheets accepted at ACM CHI 2024.

Education

Apr 2023 – Present
University of Tsukuba Doctor of Informatics (GPA: 4.0/4.3)
Digital Nature Group, Advised by Associate Professor Yoichi Ochiai
Apr 2021 – Mar 2023
University of Tsukuba Master of Informatics (GPA: 3.7/4.3)
Digital Nature Group, Advised by Associate Professor Yoichi Ochiai
Apr 2017 – Mar 2021
Meiji University Bachelor of Engineering in Mechanical Engineering
Fluid Engineering Laboratory, Advised by Professor Jun Sakakibara

Research

HIFU Embossment of Acrylic Sheets

Jun 2023 – May 2024 | ACM CHI 2024

Proposed a new embossing method using High-Intensity Focused Ultrasound (HIFU) to form arbitrary emboss patterns on acrylic sheets without molds. Built an experimental system combining HIFU transducers, a water tank, XYZ plotter, amplifier, and oscilloscope. Conducted comprehensive experiments across 51 points × 9 conditions varying amplitude (8.90–26.7 Vrms), irradiation time (1–50 s), and focal distance (32.25–69.75 mm), identifying parameter conditions that control emboss height, transparency, and line formation.

Air Talk-Starter: Air Vortex Haptic Notification for DHH Users

Apr 2021 – May 2023 | James Dyson Award Japan National Winner

Addressed the issue that Deaf/hard-of-hearing (DHH) individuals often miss the moment someone starts speaking to them, by creating a non-contact, air-vortex-based system that delivers a gentle tactile cue on the user's head. Managed all project phases from air-vortex generation theory to prototyping, control algorithm development, and user studies, achieving >90% directional accuracy at 1–2 m.

Publications

First Author

  1. Ryosei Kojima, Akihisa Shitara, Tatsuki Fushimi, Ryogo Niwa, Takayuki Hoshi, Yoichi Ochiai. "Demonstrating SHITARA: Sending Haptic Induced Touchable Alarm by Ring-shaped Air Vortex." ACM CHI 2023 Hot Desk Demo (peer-reviewed), Hamburg, Germany, Apr 2023.
  2. Ryosei Kojima, Akihisa Shitara, Tatsuki Fushimi, Ryogo Niwa, Takayuki Hoshi, Yoichi Ochiai. "SHITARA: Sending Haptic Induced Touchable Alarm by Ring-shaped Air Vortex." arXiv preprint, 2023. DOI

Co-Author

  1. Ayaka Tsutsui, Takahito Murakami, Tatsuki Fushimi, Ryosei Kojima, Kengo Tanaka, Yoichi Ochiai. "Evaluating Tactile Perception of Robot-Controlled HIFU Embossing." HRI Companion '26, pp. 558–562, 2026. DOI
  2. Ayaka Tsutsui, Tatsuki Fushimi, Takahito Murakami, Ryosei Kojima, Kengo Tanaka, Yoichi Ochiai. "HIFU Embossment of Acrylic Sheets." CHI '24, Article 431, pp. 1–23, 2024. (acceptance rate: 26%) DOI
  3. Shieru Suzuki, Kazuma Aoyama, Ryosei Kojima, Kazuya Izumi, Tatsuki Fushimi, Yoichi Ochiai. "ExudedVestibule: Enhancing Mid-air Haptics through Galvanic Vestibular Stimulation." SIGGRAPH '23 Posters, Article 41, pp. 1–2, 2023. DOI

Domestic Conference

  1. Chikane Urairi, Takayuki Hoshi, Ryosei Kojima, Tatsuki Fushimi, Yoichi Ochiai. "Investigation of Pest Detachment Effects by Air Vortex Rings for Practical Whitefly Control Robots." 69th Annual Meeting of the Japanese Society of Applied Entomology and Zoology, Makuhari Messe, Mar 2026.

Patents

Awards & Funding

Grants & Scholarships

2024–2026
University of Tsukuba Tuition Exemption (Full): ¥267,900 × 4 terms
2023–2026
JST SPRING Section 1 Research Fellow: Annual stipend of ¥2.9M (¥2.4M living expenses, ¥0.5M research funds)
2022
INNO-vation Program "Disruptive Challenge" Challenger: Top 16 / 1,717 applicants (0.9%), received ¥1,000,000
2022–2023
JASSO Type 1 Scholarship: Monthly ¥88,000, fully exempted repayment for excellent grades

Awards

2024
NEXT YOUNG ARTIST AWARD 2024, Game & Interaction Category, Excellence Award: Top 5 / 384 entries
2023
University of Tsukuba President's Award: Top honor awarded to ~12 out of 2,103 graduates (0.5%)
2022
WIRED Creative Hack Award Finalist: Top 16 / 253 teams (6.3%)
2022
28th Student CG Contest Nominee: Top 26 / 404 teams (6.4%)
2022
James Dyson Award Japan National Winner: Air Talk-Starter

Teaching Assistant (TA)

2025
"Survey and Data Analysis" TA (University of Tsukuba, Jan–Feb 2025)
2024
"Presentation Battle for Interdisciplinary Communication" TA (University of Tsukuba, Apr–Nov 2024)
2021–2022
"Introduction to Contents" TA (University of Tsukuba, Sep 2021–Jan 2022)

Research Assistant (RA)

2024–2025
Pixie Dust Technologies, Inc. & University of Tsukuba Joint Research "Digital Nature Strategic Research Platform" RA (Dec 2024–Feb 2025)
2023–2024
University of Tsukuba, Faculty of Library, Information and Media Science RA (Jul 2023–Mar 2024)
2022–2023
Pixie Dust Technologies, Inc. & University of Tsukuba Joint Research "Digital Nature Strategic Research Platform" RA (Jun 2022–Mar 2023)

Other Activities

2023
Public Outreach: Organized a public workshop at the National Museum of Emerging Science and Innovation (Miraikan)
2023
TV Appearance: Presented Air Talk-Starter on NHK's "Baribara"
2023
Invited Talk: Delivered a talk on Air Talk-Starter at IBM Japan
2021
Radio Appearance: Guest on FUTURES Yoichi Ochiai RADIO PIXIE DUST

Skills

Hardware Design
Autodesk Fusion, Autodesk EAGLE
Programming Languages
Python, MATLAB, C++, Arduino, JavaScript
Electrical Tools
Oscilloscope, Function Generator, High-speed Bipolar Power Supply
Fabrication
CNC Milling Machine, 3D Printing (FDM, SLA), Laser Cutter
Precision Measurement
Laser Doppler Vibrometer, High-speed Camera, 3-axis Stage Controller, Anemometer
Optical Tools
Femtosecond Laser, Galvanometer Scanner, Spectroradiometer

Contact

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