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Affiliation |
Engineering educational research section Information and Communication Technology Program |
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Title |
Professor |
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External Link |
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OKAZAKI Naonobu
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Degree 【 display / non-display 】
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Doctor (Engineering) ( 1992.3 Tohoku University )
Research Areas 【 display / non-display 】
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Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Communication and network engineering
Papers 【 display / non-display 】
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Usuzaki Shotaro, Takahashi Nobuya, Kamada Taiki, Aburada Kentaro, Yamaba Hisaaki, Park Mirang, Okazaki Naonobu
IEICE Communications Express 14 ( 12 ) 441 - 444 2025.12
Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：一般社団法人 電子情報通信学会
In this study, we propose a text-based CAPTCHA that utilizes human visual completion to prevent automated programs from getting through, without affecting human cognition. This CAPTCHA requires users to enter the reading of the kanji strings, whose centers are hidden behind a black bar. This method makes it challenging for machines to recognize the characters, while still allowing humans to identify the original text through their visual completion ability. We evaluate both the usability and security of the proposed CAPTCHA. To assess usability, we observed how humans respond to the CAPTCHA challenge. For the security evaluation, we tested the machine’s ability to read the kanji using a Convolutional Neural Network (CNN). The results showed that the proposed CAPTCHA achieves a success rate comparable to traditional CAPTCHAs, with a slightly shorter response time than a similar type of CAPTCHA. Furthermore, security experiments have shown that it exhibits a certain degree of resistance against simple convolutional neural networks.
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Optimal Weighted Voting-Based Collaborated Malware Detection for Zero-Day Malware: A Case Study on VirusTotal and MalwareBazaar Reviewed
Naonobu Okazaki, Shotaro Usuzaki, Tsubasa Waki, Hyoga Kawagoe, Mirang Park, Hisaaki Yamaba and Kentaro Aburada
Future Internet 16 ( 8 ) 259 2024.7
Authorship：Lead author, Corresponding author Language：English Publishing type：Research paper (scientific journal)
DOI： 10.3390/fi16080259
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Usability improvement in color constancy CAPTCHA Reviewed
Shotaro Usuzaki, Wang Yihan, Kentaro Aburada, Hisaaki Yamaba, Kayoko Takatsuka, Tetsuro Katayama, Mirang Park, and Naonobu Okazaki
IEICE Communications Express 2024.6
Authorship：Last author Language：English Publishing type：Research paper (scientific journal)
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プロジェクト・スケジュールの遅延リスク分析のための手法の開発 Reviewed
高塚佳代子, 佐藤知一, 油田健太郎, 岡崎直宣
化学工学論文集 49 ( 6 ) 159 - 165 2023.11
Authorship：Last author Language：Japanese Publishing type：Research paper (scientific journal)
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Takatsuka Kayoko, Nagatomo Yoki, Uchida Noriyuki, Ikeda Takuya, Mukunoki Masayuki, Okazaki Naonobu
Journal of Robotics, Networking and Artificial Life 10 ( 1 ) 17 - 24 2023.10
Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：ALife Robotics Corporation Ltd.
This study aimed to reduce the effect of the examining environment on accuracy by using an eye movement detection system, a VR head-mounted display. We reproduced the inspection environment in a virtual reality environment and performed the cover test, a basic inspection technique for tropia and phoria. We then developed a system that uses eye data collected by eye tracking to detect the directions and magnitudes of eye misalignment. The Maddox method, an existing testing procedure, was used to verify the accuracy. We have confirmed its effectiveness in detecting the directions and magnitudes of horizontal eye misalignment.
Books 【 display / non-display 】
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Slow HTTP POST DDoS Attack Prevention Method that Monitors Payload Size and Number of Connections
Ozaki Y., Usuzaki S., Aburada K., Yamaba H., Park M., Okazaki N.（ Role： Sole author）
Lecture Notes on Data Engineering and Communications Technologies 2026
The threat of distributed denial-of-service (DDoS) attacks has increased in recent years. In particular, the slow HTTP POST attack overwhelms web servers by maintaining slow connections with small payloads. Previous research has addressed this threat by monitoring the number of simultaneous connections and using programmable P4 switches. However, these approaches have shown limitations when facing distributed attacks from multiple IP addresses. In this study, we developed an improved defense method that monitors both the number of simultaneous connections and the payload size to more effectively identify a slow HTTP POST DDoS attack by capturing its characteristics. Experimental comparisons with existing methods demonstrated that connection-based monitoring alone is insufficient against distributed attacks, whereas our new method achieves better performance. Ultimately, implementing this method on a P4 switch is expected to reduce server load by blocking malicious traffic before it reaches the server, thereby enhancing the robustness of the entire system.
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水野 忠則 , 中村 嘉隆, 田 学軍, 清原 良三, 石原 進, 久保田 真一郎, 岡崎 直宣, 太田 賢 (通信工学), 稲村 浩, 舟阪 淳一, 油田 健太郎（ Role： Joint author）
共立出版 2024.3 （ ISBN:9784320125766 ）
Language：Japanese Book type：Textbook, survey, introduction
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ネットワークセキュリティ
関良明，河辺義信，西垣正勝，岡崎美蘭，岡崎直宣，本郷節之，岡田安功（ Role： Joint author , 全247頁（分担）142-160頁）
共立出版 2017.9
Language：Japanese Book type：Scholarly book
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コンピュータネットワーク概論
水野忠則，岡崎直宣 他（ Role： Joint author , 全269頁（分担）241-260頁）
共立出版 2014.9
Language：Japanese Book type：Scholarly book
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コンピュータ概論
白鳥則郎，岡崎直宣 他（ Role： Joint author , 全257頁（分担）172-184頁）
共立出版 2013.1
Language：Japanese Book type：Scholarly book
MISC 【 display / non-display 】
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Usuzaki S., Aburada K., Yamaba H., Katayama T., Mukunoki M., Park M., Okazaki N.
Artificial Life and Robotics 27 ( 1 ) 2022.2
Authorship：Last author Language：English Publishing type：Rapid communication, short report, research note, etc. (scientific journal) Publisher：Artificial Life and Robotics
In the original publication of the article, on Figs. 4 and 5, “CNN” should read as “MLP”. In addition, under the section “4.2 Human and machine success rate”, on the paragraph “For evaluation of the machine success …”, in the following sentence “In the attack experiment, we applied the famous color …” CNN (Convolutional Neural Network) should be corrected as MLP (Multilayer perceptron). The correct sentence should read as “In the attack experiment, we applied the famous color constancy algorithm, Gray-World, Max-RGB, Gray-Edge [11], Second Derivative Gray-Edge, and MLP (Multilayer perceptron) to images that were saved in the experiment for the human success rate
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地域通貨を用いたコミュニティ活性化支援システムの試作
小林亜衣，甲斐健太郎，岡崎直宣
宮崎大学工学部紀要 ( 36 ) 251 - 256 2007.8
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (bulletin of university, research institution) Publisher：宮崎大学工学部
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階層型ネットワークアドレス変換を用いたIP移動透過性の実現手法における安全な通信方式の検討
岡崎直宣，馬着英臣
宮崎大学工学部紀要 ( 36 ) 289 - 296 2007.8
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (bulletin of university, research institution) Publisher：宮崎大学工学部
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センサネットワークにおけるホップ数に基づくルーティング方式の提案
守田可南子，佐藤雄亮，岡崎直宣
宮崎大学工学部紀要 ( 36 ) 281 - 288 2007.8
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (bulletin of university, research institution) Publisher：宮崎大学工学部
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アドホックネットワークにおける階層型複数経路構築手法の提案と評価
油田健太郎，高辻慎吾，岡崎直宣
宮崎大学工学部紀要 ( 36 ) 273 - 280 2007.8
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (bulletin of university, research institution) Publisher：宮崎大学工学部
Presentations 【 display / non-display 】
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Proposal and implementation of a shoulder-surfing attack resistant authentication method using two shift functions International conference
Yoshihiro Kita, Fumio Sugai, Mirang Park, Naonobu Okazaki
The Second International Conference on Cyber Security, Cyber Peacefare and Digital Forensic (CyberSec2013) (Kuala Lumpur, Malaysia) The Society of Digital Information and Wireless Communications (SDIWC)
Event date： 2013.3.4 - 2013.3.6
Language：English Presentation type：Oral presentation (general)
Venue：Kuala Lumpur, Malaysia
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Proposal of a content access control scheme on a reputation value over P2P networks International conference
Kentaro Aburada, Mirang Park, Masami Ikeda, Hisaaki Yamaba, Naonobu Okazaki
The Sixth International Conference on Mobile Computing and Ubiquitous Networking (ICMU 2012) (Okinawa Japan) Information Processing Society of Japan
Event date： 2012.5.23 - 2013.5.24
Language：English Presentation type：Oral presentation (general)
Venue：Okinawa Japan
Awards 【 display / non-display 】
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Best Paper Award
2017.8 NBiS-2017
Shotaro Usuzaki, Yuki Arikawa, Hisaaki Yamaba, Kentaro Aburada, Shin-ichiro Kubota, Mirang Park, Naonobu Okazaki
Award type：Award from international society, conference, symposium, etc. Country：Japan
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技術賞
2015.4 化学工学会
高塚佳代子，高橋弘季，久保田真一郎，山場久昭，岡崎 直宣
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
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優秀論文賞
2014.7 情報処理学会
横山 絵美里，宗 裕文，川端 良樹，久保田真一郎，岡崎 直宣
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
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情報処理学会学会活動貢献賞
2012.3 情報処理学会
岡崎 直宣
Award type：Honored in official journal of a scientific society, scientific journal Country：Japan
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優秀論文賞
2007.7 情報処理学会
油田健太郎，佐藤雄亮，岡崎直宣，冨田重幸，朴 美娘
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
Grant-in-Aid for Scientific Research 【 display / non-display 】
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DXの急展開に対応する超強靭なパスワード・リスト攻撃防止基盤の確立
Grant number：22K12013 2022.04 - 2026.03
独立行政法人日本学術振興会 科学研究費基金 基盤研究(C)
Authorship：Principal investigator
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安全なモバイルクラウドサービス実現のための利用者の環境適応型認証法の提案
Grant number：17H01736 2017.04 - 2020.03
科学研究費補助金 基盤研究(B)
Authorship：Principal investigator
安全なモバイルクラウドサービス実現のための利用者の環境適応型認証法の提案
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プロジェクトマネジメントの応用的研究
Grant number：15K12463 2015.04 - 2019.03
科学研究費補助金 挑戦的萌芽研究
Authorship：Principal investigator
プロジェクトマネジメントの応用的研究 －重要家畜伝染病の防疫活動への適用－
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ユビキタス・センサネットワーキング基盤構築のための高効率・高信頼通信方式の研究
Grant number：20500069 2008.04 - 2011.03
科学研究費補助金 基盤研究(C)
Authorship：Principal investigator
ユビキタス・センサネットワーキング基盤構築のための高効率・高信頼通信方式の研究
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深層学習を用いた筋電位による多要素個人認証の複数点測定による高精度化
Grant number：24K14948 2024.04 - 2027.03
独立行政法人日本学術振興会 科学研究費基金 基盤研究(C)
Authorship：Coinvestigator(s)
Available Technology 【 display / non-display 】
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モバイル端末向け個人認証システムの開発
自動プログラムによる遠隔攻撃の対策に関する研究
匿名通信システムに関する研究Message：上記の他、IoT技術の重要な部分を担うセンサネットワークについて、そこで特に求められる信頼性や省電力に注力したネットワーク構築技術などの研究を行っています。