@article{oai:miyazaki-u.repo.nii.ac.jp:00005702,
 author = {Yamaba, Hisaaki and 山場, 久昭 and 市元, 祐弥 and Aburada, Kentaro and 油田, 健太郎 and Okazaki, Naonobu and 岡崎, 直宣 and Ichimoto, Yuya},
 journal = {宮崎大学工学部紀要, Memoirs of Faculty of Engineering, University of Miyazaki},
 month = {Jul},
 note = {According to the a growth of troubles caused by malicios programs called bots, CAPTCHA (Comletely Automated Public Turing test to tell Coputers and Humans Apart) comes to be an important roll in the current information society. CAPTCHA identifies bots from legitimate human users by requiring some questions that are easy for humans to solve but difficult for bots. However, the progress of computing technology such as OCR, bots come to be able to solve present CAPTCHAs. In order to outcome such troublesome bots, more sophisticated CAPTCHA that equips high cognitive ability like human is desired. In this paper, we propose a new CAPTCHA scheme that uses random dot patterns. Human can recognize a moving cluster filled by random dot patterns from a background filled by random dot patterns; however, loses the cluster in the background when the cluster pauses. Since image recognition by computer programs is usually carried out frame by frame, it is hard for bots to recognize a moving cluster filled by random dot patterns from a random dot pattern background. The proposed CAPTCHA requires users to answer a text that is filled by a random dot pattern and moves on a background that is also filled by another random dot pattern. Several experiments were carried out to confirm that the proposed CAPTCHA scheme has enough resistance against bots attacks using representative image recognition methods. Other experiments were also carried out to evaluate the usability of the proposed CAPTCHA scheme. The system usability scheme (SUS) was adopted in the experiments. The results of the experiments showed that the CAPTCHA scheme is usable enouth and has enoungh resistance against bots attacks.},
 pages = {349--353},
 title = {ランダムドットを用いた文字列CAPTCHAの提案},
 volume = {47},
 year = {2018},
 yomi = {ヤマバ, ヒサアキ and イチモト, ユウヤ and アブラダ, ケンタロウ and オカザキ, ナオノブ}
}