A study on attack methods using LLM in Question-Answering task　　　　　　　　　　　　　　　
鈴木 悠真; 大瀧 保広, Corresponding
暗号と情報セキュリティシンポジウム予稿集, Jan. 2025

Categorization of ICT Inquiry Data using Mail Subjects
Taisuke Kawamata; Kazuyuki Yamamoto; Yasuhiro Ohtaki, 情報系センターにおける業務の一つである問合わせ対応の効率化を目的に，問合わせデータを機械的にカテゴライズする方法を検討した．問合わせはメールで行われることが多いが，メールの本文には問合わせと無関係なノイズが多く含まれ，それらのノイズを前処理で削除するための工程が，自動的なカテゴライズを困難なものにしている．そこで本研究では，メールの件名が本文の要約であり，また短文であることからノイズが少ないという点に着目し，件名の活用方法について検討を行う．短文に含まれる単語情報を効果的に活用するため，文書の文脈を考慮することが可能な深層言語モデルBERTを用いて特徴抽出を行った．実際の問い合わせデータを対象に，抽出した特徴をクラスタリングし，人間のカテゴライズと比較した．その結果，件名を用いた分類は本文を用いた分類よりも意味としてまとまったクラスタを生成することが明らかになった．これにより，件名を活用することで，メール分析における前処理の課題を解決できる可能性が示唆された．, Academic eXchange for Information Environment and Strategy
Journal for Academic Computing and Networking, Nov. 2024, [Reviewed]

Web Applications for Sharing Teacher PC Screen to Student PCs via WebRTC
Tatsuma Okuda; Michitoshi Niibori; Hiroshi Noguchi; Yasuhiro Ohtaki; Masaru Kamada, Springer Nature Switzerland
Lecture Notes on Data Engineering and Communications Technologies, 20 Sep. 2024, [Reviewed]

証明書管理支援システムの開発と運用コストの検証
山本 一幸; 大瀧 保広,

大学ではサーバ証明書やクライアント証明書等の電子証明書を多くのシステムで活用している．茨城大学では，電子証明書として国立情報学研究所が提供する電子証明書発行サービスを利用しており，発行管理を大学の情報系センターの教職員が行っている．サーバ管理者やクライアント証明書の利用者から証明書更新や再発行に関していくつかの問題が発生している．一般的に企業では情報システム部門がすべてのサーバやパソコンを管理し，電子証明書のインストールや管理も一括で実施することが多い．しかし，大学では電子証明書の発行や配付については情報系センター等の情報システム部門が統括管理するが，運用管理については，教職員や学生が個人で管理している場合が多い．情報システム部門が統括管理していないことで更新や配付に関する運用コストが増加する傾向にある．本論文では，証明書の有効期限，更新手続き，旧証明書の失効の管理やクライアント証明書の配付等を統合して実施するための証明書管理支援システムを開発した．開発したプロトタイプシステムについて説明し，これを活用したことによる運用コスト削減について検証する．

, 一般社団法人大学ICT推進協議会
学術情報処理研究, 28 Dec. 2022

Constructing a Client Certificate Distribution System
Yasuhiro Ohtaki; Kazuyuki Yamamoto, Lead, Springer
L. Barolli et al. (eds.), Advances in Network-based Information Systems (NBiS-2022), Lecture Notes in Networks and Systems, Sep. 2022, [Reviewed]

Constructing Opaque Predicate using Homomorphic Encryption
Yohsuke Hirano,Yasuhiro Ohtaki, Corresponding, Springer
Advances in Network-based Information Systems (NBiS-2022), Lecture Notes in Networks and Systems, Sep. 2022, [Reviewed]

準同型暗号を用いたOpaque Predicateの提案　　　　　　　　　　　　　　　
平能耀介; 大瀧保広, Corresponding, 電子情報通信学会 情報セキュリティ専門委員会
暗号と情報セキュリティシンポジウム予稿集, 20 Jan. 2022

A graphical front-end interface for React.js considering state-transition diagrams.
Shotaro Naiki; Masaki Kohana; Michitoshi Niibori; Shusuke Okamoto; Yasuhiro Ohtaki; Masaru Kamada
International Journal of Grid and Utility Computing, 2022

児童・生徒向け情報セキュリティ対策を実施した附属学校ネットワークの構築
山本一幸; 大瀧保広; 野口宏; 西原忠史; 羽渕裕真; 外岡秀行, 国立大学法人 情報系センター協議会
学術情報処理研究, 01 Nov. 2021, [Reviewed]

Estimating User's Movement Path with Wi-Fi Authentication Log　　　　　　　　　　　　　　　
Jun Yamano; Yasuhiro Ohtaki; Kazuyuki Yamamoto, Corresponding, Springer
Advances in Networked-Based Information Systems. NBiS 2021. Lecture Notes in Networks and Systems, Sep. 2021, [Reviewed]

Another HTML5 Implementation of Web-Com for Embedding Chalk Annotations and Talk Voices into HTML Documents
Koki Maruyama; Yasuhiro Ohtaki; Michitoshi Niibori; Tatsuhiro Yonekura; Masaru Kamada, Web-Com is a tool for teachers to record their chalk annotations and talk voices onto a web document to produce a lively e-learning content. It was originally developed as a Windows application in 2005 and then implemented solely on the basis of HTML5 and JavaScript in 2017 so that it may work on any contemporary web browsers. The only drawback of the previous implementation in 2017 was that the original web document had to be transformed into a single static image file to appear in the resulting e-learning content and thus that the dynamical capability of the original web document is lost. This paper presents a much better implementation that produces the resulting e-learning content as another web document where the original web document, the chalk annotations, and the talk voices are embedded as they are so that the dynamical contents like hyperlinks, buttons, animations and movies in the original web document are preserved in the resulting e-learning content., Springer
Advances in Intelligent Systems and Computing, 2021

問合せデータの分散表現を用いた分類　　　　　　　　　　　　　　　
山本一幸; 大瀧保広; 佐藤伸也; 嶌田敏行; 野口宏; 羽渕裕真; 外岡秀行, 情報系センター協議会
第15回 国立大学法人情報系センター研究集会, 25 Sep. 2020, [Reviewed]

レベル分けによる多要素認証の要否の実現と認証連携の拡張　　　　　　　　　　　　　　　
野口宏; 大瀧保広; 山本一幸; 西原忠史; 外岡秀行, 情報系センター協議会
第15回 国立大学法人情報系センター研究集会, 25 Sep. 2020, [Reviewed]

茨城大学における遠隔授業／テレワーク支援　　　　　　　　　　　　　　　
大瀧保広; 嶌田敏行; 山本一幸; 野口宏; 佐藤伸也; 外岡秀行; 羽渕裕真, 国立大学法人 情報系センター協議会
第15回 国立大学法人情報系センター研究集会, 25 Sep. 2020, [Reviewed]

短期間での多要素認証への移行と定常運用に向けた業務の自動化　　　　　　　　　　　　　　　
大瀧保広; 西原忠史; 山本一幸; 野口宏, Lead, 情報系センター協議会
第15回 国立大学法人情報系センター研究集会, 25 Sep. 2020, [Reviewed]

茨城大学における遠隔授業／テレワーク支援
大瀧保広; 嶌田敏行; 山本一幸; 野口宏; 佐藤伸也; 外岡秀行; 羽渕裕真, Lead, 国立大学法人 情報系センター協議会
学術情報処理研究, 25 Sep. 2020, [Reviewed]

レベル分けによる多要素認証の要否の実現と認証連携の拡張
野口宏; 大瀧保広; 山本一幸; 西原忠史; 外岡秀行, 国立大学法人 情報系センター協議会
学術情報処理研究, 25 Sep. 2020, [Reviewed]

問合せデータの分散表現を用いた分類
山本一幸; 大瀧保広; 佐藤伸也; 嶌田敏行; 野口宏; 羽渕裕真; 外岡秀行, 国立大学情報系センター協議会
学術情報処理研究, 25 Sep. 2020, [Reviewed]

〔Major achievements〕A Practical Implementation of Searchable Encrypted Audit Logging System
Ohtaki Y.; Togashi K., Lead, Springer
Advances in Networked-Based Information Systems. NBiS 2020. Advances in Intelligent Systems and Computing, Sep. 2020, [Reviewed]

印刷環境による学生の印刷行動の変化
大瀧 保広; 野口 宏; 山本 一幸; 外岡 秀行; 鎌田 賢, Lead
学術情報処理研究, 17 Sep. 2019, [Reviewed]

情報セキュリティインシデント対応のための茨大型情報共有システムの構築と検証
山本 一幸; 大瀧 保広; 野口 宏; 羽渕 裕真; 外岡 秀行
学術情報処理研究, 17 Sep. 2019, [Reviewed]

Implementation of Interactive Tutorial for IslayPub by Hooking User Events　　　　　　　　　　　　　　　
Daisuke Tanaka; Masaki Kohana; Michitoshi Niibori; Yasuhiro Ohtaki; Shusuke Okamoto; Masaru Kamada
The 8th International Workshop on Web Services and Social Media (WSSM-2019), Sep. 2019, [Reviewed]

An Image Source Checker for Educational Presentation Materials
Yasuhiro Ohtaki, Springer
Advances in Network-Based Information Systems,,Lecture Notes on Data Engineering and Communication Technologies, Sep. 2018, [Reviewed]

Transition of Information Studies on Japanese Secondary Education - Meta Text Analysis of the Government Course Guidelines, 2018　　　　　　　　　　　　　　　
Yuki Watanabe; Masanao Kobayashi; Noboru Nakamichi; Rieko Inaba; Shinya Watanabe; Takashi Hasuike; Takeo Tatsumi; Tomoharu Ugawa; Yasuhiro Ohtaki; Yoshifumi Yamamoto; Kei Onishi; Toshio Matsuura; Hiroshi Ishikawa
Conference Proceedings of Hawaii International Conference on Education 2018, Jan. 2018, [Reviewed]

A university information system made robust against natural disasters by taking advantage of remotely distributed campuses
Hiroshi Noguchi; Yasuhiro Ohtaki; Masaru Kamada, InderScience
International Journal of Space-Based and Situated Computing, Nov. 2016, [Reviewed]

Deployment of Single Sign-On Environment for Office365 and Shibboleth with multi factor authentication
Hiroshi Noguchi; Yasuhiro Ohtaki; Yukio Takahashi; Masaru Kamada, 学術情報処理研究編集委員会
Journal for Academic Computing and Networking, Sep. 2016, [Reviewed]

Study of future strategy ICT center - Better quality of services in the case of Ibaraki University –　　　　　　　　　　　　　　　
Hiroshi Noguchi; Yasuhiro Ohtaki; Masaru Kamada; Masanori Itaba; Satoru Ozawa
Proceedings of International Symposium on ICT in Development 2015, Nov. 2015, [Reviewed]

Design and Practice of File Backup System Taking Advantage of Remotely Distributed Campuses
Hiroshi Noguchi; Yasuhiro Ohtaki; Masaru Kamada, We present a file backup system designed for a university on the basis of its experiences with the 2011 east Japan earthquake. This system has two levels of security: (1) The web site for public relations and the e-mail systems for communications that will work continuously even in the case of commercial power failure. (2) The personal computer systems that will be down during power failure but will restart working without any loss of data as soon as the power supply is back. The former has been implemented by employing a private cloud computing platform and a public one in combination. To the latter, the same cloud-computing approach was not applicable because it causes latency and extra cost of communications in the normal time to keep the frequently accessed data in a cloud storage. Fortunately, this particular university has three campuses so far away that one may be destroyed by a single disaster but the other two will survive. Taking advantage of the remote campuses, we designed and implemented a file storage system that keeps the original copy on-premise in a campus and its backup copy in one of the other two campuses. Its operations have shown that the communication traffic among the campuses increased only by half in order to keep the data safe against natural disasters., IEEE
PROCEEDINGS 2015 18TH INTERNATIONAL CONFERENCE ON NETWORK-BASED INFORMATION SYSTEMS (NBIS 2015), 2015

Deployment of Local Private Data Center for BCP and Plan for Its Use
Hiroshi Noguchi; Yasuhiro Ohtaki; Masaru Kamada
Journal for Academic Computing and Networking, Sep. 2014, [Reviewed]

How to update documents verifiably in searchable symmetric encryption
Kaoru Kurosawa; Yasuhiro Ohtaki, In a searchable symmetric encryption (SSE) scheme, a client can store encrypted documents to a server in such way that he can later retrieve the encrypted documents which contain a specific keyword, keeping the keyword and the documents secret. In this paper, we show how to update (modify, delete and add) documents in a verifiable way. Namely the client can detect any cheating behavior of malicious servers. We then prove that our scheme is UC-secure in the standard model. © Springer International Publishing 2013., Springer Verlag
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2013, [Reviewed]

File backup system taking advantage of remotely distributed campuses
Hiroshi NOGUCHI; Yasuhiro OHTAKI; Masaru KAMADA, 学術情報処理研究編集委員会
Journal for Academic Computing and Networking, 13 Sep. 2012, [Reviewed]

UC-secure searchable symmetric encryption
Kaoru Kurosawa; Yasuhiro Ohtaki, For searchable symmetric encryption schemes (or symmetric-key encryption with keyword search), the security against passive adversaries (i.e. privacy) has been mainly considered so far. In this paper, we first define its security against active adversaries (i.e. reliability as well as privacy). We next formulate its UC-security. We then prove that the UC-security against non-adaptive adversaries is equivalent to our definition of privacy and reliability. We further present an efficient construction which satisfies our security definition (hence UC-security). © 2012 Springer-Verlag.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2012, [Reviewed]

Real-time cheat-free gaming on the basis of time-stamp service　　　　　　　　　　　　　　　
Shunsuke Mogaki; Masaru Kamada; Tatsuhiro Yonekura; Shusuke Okamoto; Yasuhiro Otaki; Mamun Bin Ibne Reaz
International Journal of Computer Science and Network Security, Jan. 2009

Estimation of color images by box splines from their observation through honeycomb color filter
Tomoko Yokokawa; Masaru Kamada; Yasuhiro Ohtaki; Tatsuhiro Yonekura, An experimental test has been done on the suitability of box splines for the estimation of color images from their observation through the honeycomb color filter. The estimation is made by following the framework of consistent sampling by Unser and Aldroubi. Numerical evaluation of the estimation errors has shown that the best estimation may be made by choosing the box splines which are twice locally averaged along each of the three axes consisting of the unilateral triangular mesh. A close look at estimated images has indicated that those box splines are almost free from directional jaggy noises that the traditional B-splines suffer from., IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, Dec. 2006

Estimation of color images by box splines from their observation through honeycomb color filter
Tomoko Yokokawa; Masaru Kamada; Yasuhiro Ohtaki; Tatsuhiro Yonekura, An experimental test has been done on the suitability of box splines for the estimation of color images from their observation through the honeycomb color filter. The estimation is made by following the framework of consistent sampling by Unser and Aldroubi. Numerical evaluation of the estimation errors has shown that the best estimation may be made by choosing the box splines which are twice locally averaged along each of the three axes consisting of the unilateral triangular mesh. A close look at estimated images has indicated that those box splines are almost free from directional jaggy noises that the traditional B-splines suffer from., IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, Dec. 2006, [Reviewed]

A scheme for partial disclosure of transaction log
Y Ohtaki; M Kamada; K Kurosawa, To investigate cyber-criminals, Police sometimes asks Administrator of a computer system to disclose the whole transaction log. Administrator, however, wants to protect the privacy of innocent users. This paper presents a solution for the disclosure/privacy problem of transaction log. In this scheme, Police can search over the encrypted records of the transaction log by keywords. The administrator discloses only the records which include the keyword, but nothing more. Police can verify that the administrator faithfully disclosed all the records which include the keyword., IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES, Jan. 2005, [Reviewed]

A network game based on fair random numbers
Masaru Kamada; Kaom Kurosawa; Yasuhiro Ohtaki; Shusuke Okamoto, A compromising technique is proposed for deterring clients from cheating by robot players in skill-based real-time network games. This technique is to inject a fair random noise into the manual input for a real-time game modeled as a chaotic dynamical system. The fair random noise is determined by means of the bit commitment protocol so that neither host nor client can control the noise in their favor. A scenario possibly plotted by a robot player for its victory may be spoiled by slight noise injection because of the sensitivity of chaotic systems to the input. The noise injection brings a luck-based factor into a skill-based game. In this sense, the technique proposed in this paper is not a solution but a compromise for the inherent problem of robot players with the skill-based network games. An example implementation of pinball is presented. Copyright © 2005 The Institute of Electronics, Information and Communication Engineers., Institute of Electronics, Information and Communication, Engineers, IEICE
IEICE Transactions on Information and Systems, 2005

Constructing a searchable encrypted log using encrypted inverted indexes
Y Ohtaki, Searchable encrypted log provides a facility to disclose only records which match some specified conditions. However, searching on an encrypted log takes a long time because checking for the condition usually requires a vast number of public key operations. In the field of plain text search, inverted index is a typical data structure to improve the performance of search speed which turns a bunch of comparison into a simple table lookup. This paper introduces an encrypted version of inverted index which can be used for a searchable encrypted log. Encrypted inverted index enables to determine all records that contain a keyword while contents of other records are kept secret. Statistic information such as frequency of each word is also not revealed. A prototype system is implemented to show the efficiency., IEEE COMPUTER SOC
2005 International Conference on Cyberworlds, Proceedings, 2005, [Reviewed]

Proxy caching algorithms to reduce response delay　　　　　　　　　　　　　　　
Qusai Abuein; Susumu Sibusawa; Yasuhiro Ohtaki, October 1-4, 2002, Tsukuba, JAPAN
Proceedings of IASTED International Conference, Networks, Parallel and Distributed Processing, and Applications, 2002, [Reviewed]

Three-dimensional measurement approach for seal identification
R Haruki; M Rioux; Y Ohtaki; T Horiuchi; K Yamamoto; H Yamada; K Toraichi, This paper proposes a new approach to deal with the various quality of the reference impressions by measuring the seal to register as 3D (three-dimensional) image, that is, range image. By registering a seal as 3D image, it becomes possible to construct various 2D impressions from it according to the affixing conditions of the reference impression such as the affixing slant, the affixing pressure, the state of the ink on the seal surface and so on. Then, the accurate and easy identification of the seals will be possible by comparing the constructed impression with the reference impression. The performance is verified by experiment, and the result shows that plural 2D impressions according to the affixing conditions can be constructed from only one 3D image of the registered seal., IEICE-INST ELECTRON INFO COMMUN ENG
IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS, Dec. 1995, [Reviewed]

On Method of Extracting Joint Points for Generating Function-Fonts of Multi-Symbols
Takahiko Horiuchi; Kazuo Toraichi; Yasuhiro Ohtaki, 電気学会
電気学会論文誌, Dec. 1993, [Reviewed]

COMPRESSING DATA VOLUME OF LEFT-VENTRICULAR CINEANGIOGRAMS
K TORAICHI; T HORIUCHI; RE KALMAN; Y OHTAKI; H NAGASAKI, In this paper a method of compressing data volume for left ventricular cineangiograms is proposed. This method enables digital-optical discs to store the cineangiograms with an equivalent recording density to that of HDTV VTR's while preserving the quality of the original image. The data volume of the cineangiograms is compressed by approximating function and storing its coefficients. With this method, each cineangiogram frame is first decomposed into three regions: the inner part, the inner wall, and the background (using a statistical method previously reported by the authors). Each region is then compressed by means of a difference operation and an adaptive approximation with smooth functions.
Performance is tested on 20 cases using actual cineangiograms. The specifications were verified for a spatial resolution of 1000 TV lines, a dynamic range of 60 dB, an SNR of 40 dB [p-p/rms], volume compression to 7% of the original volume, and 0.19 [second/frame] for decoding on a 1.7 MFLOPS computer., IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, Jun. 1993, [Reviewed]

On a Method of Restoring a Polyhedron from Three Orthographic Views by Relaxation Matching
HORIUCHI Takahiko; TORAICHI Kazuo; YAMAMOTO Kazuhiko; YAMADA Hiromitsu; OHTAKI Yasuhiro, 図面データの正確さを前提とした三面図から多面体を復元する手法は,論理的な規則を用いることによって確立された.手書き三面図を入力とした多面体復元システムの構築を目的とするとき,データに生じる誤差を吸収できる柔軟な多面体復元手法が必要である.本論文は,頂点の座標値に誤差をもつワイヤフレームモデルから,多面体を復元することを目的としている.復元手法として,規則を用いた手法を適用すると,誤差の影響によって,多面体を構成する面の候補が増加するため,探索すべき組合せの数の爆発が生じてしまう.そこで,データの誤差を吸収でき,かつ計算量を指数関数的に増大させない手法が必要となる.本論文では,多面体復元手法として,確率的弛緩法を用いている.復元は,座標値の誤差の影響によって確定的に定められない面の対応を確率的に取り扱い,最も確からしい対応を選択することによって行われる.本手法を種々の例題に適用することによって,その有効性を明らかにしている., The Institute of Electronics, Information and Communication Engineers
The Transactions of the Institute of Electronics,Information and Communication Engineers., 25 Jan. 1993, [Reviewed]

Compressing EEG Data Using Adaptive Function Approximation
Kazuo Toraichi; Youji Ishiyama; Yasuhiro Ohtaki; Ryoji Haruki, 電気学会
電気学会論文誌, Jan. 1993, [Reviewed]

DATA-COMPRESSION METHOD OF LEFT-VENTRICULAR CINEANGIOGRAMS FOR THEIR DIGITAL DATABASE SYSTEM
Y OHTAKI; K TORAICHI; T HORIUCHI; F NAGASAKI, Victoria, British Columbia, Canada, I E E E
IEEE PACIFIC RIM CONFERENCE ON COMMUNICATIONS, COMPUTERS AND SIGNAL PROCESSING : PROCEEDINGS, VOLS 1 AND 2, 1993, [Reviewed]

RESTORING TO A POLYHEDRON FROM 3 ORTHOGRAPHIC VIEWS BY RELAXATION MATCHING METHOD
T HORIUCHI; K TORAICHI; Y OHTAKI; K YAMAMOTO; H YAMADA, I E E E
IEEE PACIFIC RIM CONFERENCE ON COMMUNICATIONS, COMPUTERS AND SIGNAL PROCESSING : PROCEEDINGS, VOLS 1 AND 2, 1993, [Reviewed]

A Multi-stage algorithm of extracting joing points for generating function-fonts　　　　　　　　　　　　　　　
Ryoji Haruki; Kazuo Toraichi; Yasuhiro Ohtaki
Proceedings of the 2nd International Conference on Document Analysis and Recognition, 1993, [Reviewed]

ON COMPRESSING METHOD OF EEG DATA FOR THEIR DIGITAL DATABASE
Y OHTAKI; K TORAICHI; Y ISHIYAMA, I E E E
ICASSP-92 - 1992 INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING, VOLS 1-5, 1992, [Reviewed]

A method of automatically compressing fonts with high resolution　　　　　　　　　　　　　　　
Y.Ohtaki; K.Toraichi; T.Horiuchi; M.Kamada, Saint-Malo, France
Proceedings of the 1st International Conference on Document Analysis and Recognition, 30 Sep. 1991, [Reviewed]

茨城大学における特色ある取り組み : 「情報戦略機構」の新設 4つの力を結集し情報インフラ整備から情報戦略企画まで担う
羽渕 裕真; 大瀧 保広
文部科学教育通信, 10 Oct. 2022, [Invited]

Deployment of Local Private Data Center for BCP and Plan for Its Use
野口 宏; 大瀧 保広; 鎌田 賢
学術情報処理研究 Journal for academic computing and networking, 25 Sep. 2014

File Manager that Shows Off Notes Out of the Files
Satoshi Kozawa; Michitoshi Niibori; Yasuhiro Ohtaki; Masaru Kamada
2014 17TH INTERNATIONAL CONFERENCE ON NETWORK-BASED INFORMATION SYSTEMS (NBIS 2014), 2014, [Reviewed]

A Platform for Collaborative Creation of Identification Guide on the Web　　　　　　　　　　　　　　　
Satomi Suzuki; Yasuhiro Ohtaki
Proc. of the 6th International Student Conference at Ibaraki University, 13 Nov. 2010, [Reviewed]
Last

Partial disclosure of searchable encrypted data with support for boolean queries
Yasuhiro Ohtaki
ARES 2008: PROCEEDINGS OF THE THIRD INTERNATIONAL CONFERENCE ON AVAILABILITY, SECURITY AND RELIABILITY, 2008, [Reviewed]

Time-stamp service makes real-time gaming cheat-free
Shunsuke Mogaki; Masaru Kamada; Tatsuhiro Yonekura; Shusuke Okamoto; Yasuhiro Ohtaki; Mamun Bin Ibne Reaz
Proceedings of the 6th ACM SIGCOMM Workshop on Network and System Support for Games, NetGames '07, 2007, [Reviewed]

A Proposal of Client Oriented Digital Content Distribution Model　　　　　　　　　　　　　　　
Toshihiro SUZUKI; Yasuhiro OHTAKI; Tatsuhiro YONEKURA
電子情報通信学会2種研究会第5回サイバーワールド研究会, 07 Dec. 2006

暗号化ロギング装置の実装　　　　　　　　　　　　　　　
佐藤公保; 大瀧保広; 鎌田賢; 黒澤馨
平成１６年度 第１回茨城大学サテライトベンチャービジネスラボラトリ共同研究開発センター合同成果報告会予稿集, 16 Sep. 2004

マルチメディアとセキュリティの新技術　　　　　　　　　　　　　　　
米倉達広; 渋沢進; 新納浩幸; 岡本秀輔; 大瀧保広
財団法人日立地区産業支援センター主催「先端・基盤技術研究会」パネル討論会講演集, Mar. 2004

ログの証拠保全と捜査協力のためのプラットフォーム　　　　　　　　　　　　　　　
財団法人 日本地区産業支援センター 平成15年度 地域産学連携強化支援事業活動報告書, Mar. 2004

超流通とコンテンツID　　　　　　　　　　　　　　　
大瀧保広
平成15年度 第６回技術部研修会技術発表報告集, 2003, [Invited]

Protecting user's privacy while collecting usage records on superdistribution
OHTAKI Yasuhiro
IPSJ SIG Notes, 02 Jun. 2000

An Access Log Management Scheme Based on Superdistribution Technology
Masaji Kawahara; Yasuhiro Ohtaki
情報処理学会 電子知的財産社会基盤研究会報告, 02 Jun. 2000

Superdistribution in the context of open-source software
Masaji Kawahara; Yasuhiro Ohtaki
情報処理学会 電子化知的財産・社会基盤研究会研究報告, 02 Jun. 2000

Proceting user's privacy while collecting usage records on superdistribution　　　　　　　　　　　　　　　
Yasuhiro Ohtaki
電子化知的財産・社会基盤研究会技術報告, 02 Jun. 2000

Handling Usage Records for Multible Accounts in the Prototype Superdistribution Label Reader
村上耕平; 進藤重直; 中村貴輝; 大瀧保広
情報処理学会 電子化知的財産・社会基盤研究会 研究報告, 30 Jan. 1999

ディジタル情報の権利保護技術
大瀧保広
情報の科学と技術, 1998

Network Community and Superdistribution　　　　　　　　　　　　　　　
Yasuhiro Ohtaki
筑波ネットワーク研究, 02 Aug. 1997

高速ネットワーク・大容量メディア時代の著作権管理システム　　　　　　　　　　　　　　　
M.Kawahara; R.Mori; Y.Ohtaki
OHM, Aug. 1997

ソフトウェア超流通技術報告　　　　　　　　　　　　　　　
森亮一; 河原正治; 大瀧保広
日本電子工業振興協会97-シ-1 マイクロコンピュータの高度利用に間する調査研究報告書, Mar. 1997

Superdistribution for Digital Contents　　　　　　　　　　　　　　　
Masaji Kawahara; Ryoichi Mori; Yasuhiro Ohtaki
画像電子学会誌, 1997

Business Infrastructures on Multimedia Networks　　　　　　　　　　　　　　　
Yasuhiro Ohtaki; Ryoichi Mori; Masaji Kawahara
Journal of the Robotics Society of Japan, 1997

超流通 : 知的財産権処理のための電子技術
森亮一; 河原正治; 大瀧保広
情報処理学会誌, Feb. 1996

ソフトウェア超流通技術報告　　　　　　　　　　　　　　　
森亮一; 河原正治; 大瀧保広
日本電子工業振興協会96-シ-1,マイクロコンピュータに関する 調査研究報告書, 1996

Developing Environment on Superdistribution Architecture
Yasuhiro Ohtaki
Technical Report of IEICE ISEC94, 1994

超流通技術調査報告　　　　　　　　　　　　　　　
森亮一; 河原正治; 大瀧保広
日本電子工業振興協会92-パ-6 マイクロコンピュータに関する調査報告書, Mar. 1992

Cryptographic managements for Superdistribution　　　　　　　　　　　　　　　
Yasuhiro Ohtaki; Ryoichi Mori
電子情報通信学会技術研究報告, 1991

The Accounting Process in Software Usage Monitor for Superdistribution
Shinichi Ueki; Yasuhiro Ohtaki; Ryoichi Mori
情報処理学会 情報システム研究会 研究報告, 1990

Superdistribution Architecture　　　　　　　　　　　　　　　
Ryoichi Mori; Masaji Kawahara; Masahide Shinozaki; Yoshiyuki Akiba; Yasuhiro Ohtaki
Proceedings on The 1990 Symposium on Cryptography and Information Security, 1990, [Reviewed]

An Overview of Superdistribution Technology　　　　　　　　　　　　　　　
Masaji Kawahara; Yasuhiro Ohtaki; Ryoichi Mori
情報処理学会 電子化知的財産・社会基盤研究会 研究報告, 19 Sep. 1989

Recent Status of Superdistribution Research Project　　　　　　　　　　　　　　　
Ryoichi Mori; Masaji Kawahara; Masahide Shinozaki; Yasuhiro Ohtaki
情報処理学会「利用者指向の情報システム」シンポジウム, 1989

デジタルネイティブのための情報リテラシー　　　　　　　　　　　　　　　
大瀧保広; 山本一幸; 羽渕裕真, Joint work
学術図書出版, 30 Mar. 2024
9784780612288

データ駆動時代の情報リテラシー　　　　　　　　　　　　　　　
大瀧保広; 山本一幸; 羽渕裕真, Joint work
学術図書出版, Mar. 2020
9784780608069

Academic Information Literacy　　　　　　　　　　　　　　　
Miyuki Uno; Yasuhiro Ohtaki; Hiroshi Noguchi; Hiromasa Habuchi, Joint work
学術図書出版, 20 Mar. 2015
9784780604290

準同型暗号を用いたOpaque Predicateの提案　　　　　　　　　　　　　　　
平能耀介 大瀧保広
2022年度 暗号と情報セキュリティシンポジウム, 20 Jan. 2022, 電子情報通信学会 情報セキュリティ研究専門委員会
20220118, 20220121

茨城大学におけるダークネット宛通信のハニーポットによる分析と比較　　　　　　　　　　　　　　　
戸谷 信暁; 米山 一樹; 大瀧 保広; 山本 一幸; 西原 忠史
2020年度 暗号と情報セキュリティシンポジウム, 28 Jan. 2020
20200128, 20200131

Forward Privacyを考慮した動的な検索可能暗号　　　　　　　　　　　　　　　
佐藤尋時; 大瀧保広
第32回暗号と情報セキュリティシンポジウム, 23 Jan. 2015, 電子情報通信学会情報セキュリティ研究専門委員会

柱状回転体を用いたCAPTCHAの提案　　　　　　　　　　　　　　　
木村祐貴; 大瀧保広
第32回暗号と情報セキュリティシンポジウム, 23 Jan. 2015, 電子情報通信学会情報セキュリティ専門委員会

Practical Dynamic SSE with Forward Privacy　　　　　　　　　　　　　　　
Hirotoki Sato; Yasuhiro Ohtaki
ISCIU10, 15 Nov. 2014, Ibaraki University

A Proposal of CAPTCHA Using Rotating Prismatic Objects　　　　　　　　　　　　　　　
Yuki Kimura; Yasuhiro Ohtaki
ISCIU10, 15 Nov. 2014, Ibaraki University

How to Update Documents Verifiably in Symmetric Searchable Encryption　　　　　　　　　　　　　　　
Kaoru KUROSAWA and Yasuhiro OHTAKI
Crytography and Network Security 2013,ecture Notes in Computer Science, 01 Nov. 2013

A Platform for Collaborative Creation of Identification Guide on the Web　　　　　　　　　　　　　　　
Satomi Suzuki; Yasuhiro Ohtaki
Proc. of the 6th International Student Conference at Ibaraki University, 13 Nov. 2010

Partial disclosure of searchable encrypted data with support for boolean queries　　　　　　　　　　　　　　　
Yasuhiro Ohtaki
Third International Conference on Availability, Reliability and Security, 06 Mar. 2008, IEEE

Constructing an Encrypted Searchable Log using Encrypted Inverted Indexes　　　　　　　　　　　　　　　
Yasuhiro Ohtaki
International Conference on CYBERWORLDS, Nov. 2005

The World of Superdistribution - In the case of digital audio data -　　　　　　　　　　　　　　　
Yasuhiro Ohtaki
Proceedings of the 1996 engineering sciences society conference of IEICE, 18 Sep. 1996

Apr. 2018 - Present

Apr. 2017 - Present

Apr. 2017 - Present

2008 - Present

2010 - 2020

Apr. 2004 - Mar. 2009

2008

1994 - 1997

2002 - Present, IEEE

1996 - Present, 電子情報通信学会

Jul. 1989 - Present, 情報処理学会

検索可能暗号の応用システムに関する研究
基盤研究(C)
茨城大学
01 Apr. 2018 - 31 Mar. 2023

A Study on a Robust Log Storage based on P2P network　　　　　　　　　　　　　　　
基盤研究(C)
Oct. 2010 - Mar. 2014

デジタル情報の権利保護機構に関する研究
奨励研究(A)
茨城大学
1995 - 1995

6095057, 特開2014-174661, 特願2013-45246, 検索システム、検索方法および検索プログラム
黒澤馨、大瀧保広

5970193, 特開2013-161154, 特願2012-20691, 検索システム、検索方法および検索プログラム
黒澤馨、大瀧保広

特願2003-126244, アクセスログ管理方法

意外と身近なサイバー攻撃　　　　　　　　　　　　　　
lecturer
茨城県県北生涯学習センター, 現代的課題対策講座「G4備えあれば患いなし」, 26 Jun. 2022 - 26 Jun. 2022