Open Access Collection of International and Scholarly Papers
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SDNにおけるDDoS攻撃のリアルタイム二段階検知システムの研究
Full text link東京海洋大学修士(工学)東京海洋大学修士学位論文 2024年度(2025年3月) 海洋システム工学 修士 第4598号指導教員: 大島浩太全文公表年月日: 2025-06-13master thesi
氷再結晶化挙動の評価方法とそのカッパ-カラギーナン含有糖溶液への応用
Full text link東京海洋大学博士(海洋科学)東京海洋大学博士学位論文 2024年度(2025年3月) 応用生命科学 課程博士 甲715号指導教員: 松川真吾doctoral thesi
Captive spawning of cone snails, Conus fulmen and Conus pulicarius (Gastropoda: Neogastropoda: Conidae)
No full textLaboratory culture experiments have been conducted to investigate larval development in cone snails of the genus Conus, primarily focusing on Hawaiian species. As a foundation for studying the larval biology of Japanese Conus species, the present study examined captive spawning in C. fulmen and C. pulicarius. Conus fulmen was cultured in aquariums at 24, 26, and 28 °C, and C. pulicarius at 23 and 26 °C. Spawning occurred at 24 °C for C. fulmen and at 26 °C for C. pulicarius, with both species producing egg capsules containing viable eggs.公開日: 2025-06-01journal articl
A study on AIS positional error analysis and transmission frequency requirements of attitude data for future vessel monitoring
No full textAutomatic Identification System (AIS) provides estimated position time along with reception time and a time stamp at the receiving station; however, the exact position estimation time remains unidentified. Therefore, this study examines the extent of positional error when using current AIS reception time. As a result, a maximum positional error of 116.9 m was observed between AIS and RTK-GPS (Real-Time Kinematic GPS). Subsequent time correction reduced this error to less than 10 m, with the product of ship speed and correction time nearly matching the error pre-correction. Consequently, it was concluded that transmitting position estimation time is essential for maintaining the reliability of Position Accuracy transmitted by AIS or VHF Data Exchange System (VDES). Furthermore, VDES may possess the communication capacity to transmit and receive vessel attitude data. Therefore, to assess the required transmission frequency, the data transmission period of roll and pitch attitude data was analysed through the mutual correlation of acceleration and angular velocity. The results indicated that the correlation coefficient for each axis exceeded 0.65 at frequencies of 0.5 Hz or higher.公開日: 2025-05-2618K1396022K04550journal articl
Custom-made medium approach for effective enrichment and isolation of chemolithotrophic iron-oxidizing bacteria
No full textChemolithotrophic neutrophilic iron (Fe)-oxidizing bacteria, which mainly belong to the family Gallionellaceae, universally prevail in terrestrial environments changing Fe cycling. However, they are typically recognized as difficult-to-culture microbes. Despite efforts, there are few Fe(II)-oxidizing lithotroph isolates; hence, their physiological and ecological knowledge remains limited. This limitation is largely owing to difficulties in their cultivation, and we hypothesize that the difficulty exists because substrate and mineral concentrations in the cultivation medium are not tuned to a specific environmental condition under which these organisms live. To address this hypothesis, this study proposes a novel custom-made medium approach for chemolithotrophic Fe(II)-oxidizing bacteria; a method that manipulates medium components through diligent analysis of field environment. A new custom-made medium simulating energy substrates and nutrients under the field condition was prepared by modifying both chemical composition and physical setup in the glass-tube medium. In particular, the modification of the physical setup in the tube had a significant effect on adjusting dissolved Fe(II) and O2 concentrations to the field environment. Using the medium, Gallionellaceae members were successfully enriched and a new Gallionellaceae species was isolated from a natural hot spring site. Compared with conventional medium, the custom-made medium has significantly higher ability in enriching Gallionellaceae members.公開日: 2025-05-0519H0308719H0430221K1987123K2704223H00534journal articl
Design of a biplane hyper-efficiency trawl door (HETD) through structure optimization
No full textBased on the developed biplane hyper-lift trawl door (HLTD), a structure optimization approach integrating a radial basis function neural network, a multi-objective genetic algorithm, and computational fluid dynamics (CFD) analysis was employed to design a biplane hyper-efficiency trawl door (HETD), with the objective of achieving reduced fuel consumption for the same swept sea area. The mechanism by which the biplane HETD outperformed the biplane HLTD in hydrodynamic performance at an attack angle of 20° was clarified through variance analysis and CFD visualization. Hydrodynamic experiments confirmed that the maximum lift coefficient of the biplane HETD was 2.11, which was slightly smaller than that of the biplane HLTD (2.18), while the corresponding drag coefficient decreased by 27.6%, resulting in a significant increase of 30.0% in the lift-to-drag ratio. The stall angle of the biplane HETD was also reduced by 5° compared to the biplane HLTD. Subsequently, a pair of sleds was attached to the bottom of the biplane HETD to reduce contact with the seabed and thereby reduce friction without affecting its hyper-efficiency characteristics.公開日: 2025-01-24journal articl
Physical and chemical oceanographic data during Umitaka-maru cruise of the 61st Japanese Antarctic Research Expedition in January 2020
No full textThe Southern Ocean connects all major ocean basins and plays a pivotal role in the meridional overturning circulation of global oceans. High-quality physical (temperature, salinity, and dissolved oxygen) and chemical (nutrients) oceanographic data from the Southern Ocean are thus critical for an improved understanding of future climates. As part of the Japanese Antarctic Research Expedition, Umitaka-maru have annually observed high-quality conductivity-temperature-depth (CTD) and water sampling data (salinity, dissolved oxygen, and nutrients) along a 110°E transect in January. Sea surface temperature and salinity were obtained continuously with a thermosalinograph (TSG) along the cruise track between the ports of Fremantle and Hobart. Data quality was validated by following as far as possible the recommendations for instruments and methods of the Global Ocean Ship-Based Hydrographic Investigation Program. This report presents the latest data collected in 2020 and is the fourth report for this journal, of which the first presented data collected in 2017.公開日: 2025-06journal articl
Reframing David Lyon’s Argument on the Relationship between Risk and Surveillance: Through Comparing Surveillance Society Theory with Reflexive Modernization Theory
Full text linkデイヴィッド・ライアンは、現代社会における監視の諸問題を主たる研究の対象としていることで知られる社会学者である。その研究成果は社会学をはじめとする研究領域で頻繁に引用されてきたが、どのような思想や理論に基づいたものであるのかということは、これまでほとんど顧みられてこなかった。ライアンは理論研究と事例研究の両方を視野に入れ、自身の主張との相違や関連性を多角的に論じている。その一例として、社会学者のアンソニー・ギデンズやウルリッヒ・ベックによる再帰的近代化論及びその一部であるリスク社会論に、本稿では注目する。ライアンは、監視とリスクの関係を問う過程で、これらの人物の研究成果に繰り返し言及し、自身の主張との関連性を示している。しかし、その記述の多くは断片的にとどまり、両者の見解や議論の異同は必ずしも明確ではない。以上のような認識に基づいて、ギデンズ及びベックとの比較検討を通じて、ライアンによる監視とリスクの関係をめぐる議論を体系的に再構成し、その意義とさらなる展開の可能性を示すことが、本稿の課題である。David Lyon is a sociologist known for his research on the issues of surveillance in the contemporary society. His research findings have been frequently cited in sociology and other fields of research, but little attention has been paid to the ideas and theories on which his research is based. Lyon discusses the differences and connections with his own claims from various angles taking into account both theoretical research and case studies. As an example, this paper focuses on reflexive modernization theory and risk society theory, which is its part, by sociologists Anthony Giddens and Ulrich Beck. Lyon repeatedly refers to their research findings and shows the relevance of his own argument in the process of questioning the relationship between surveillance and risk. However, most of his descriptions remain fragmentary, and the differences and similarities between their understandings and arguments are not necessarily clear. Based on the above-mentioned concerns, the purpose of this paper is to reframe systematically Lyon's argument of the relationship between surveillance and risk through a comparative study with Giddens and Beck, and to show its significance and the possibility of further development.萩原優騎: 東京海洋大学学術研究院海洋政策文化学部門Yuki HAGIWARA: Department of Marine Policy and Culture, Tokyo University of Marine Science and Technology (TUMSAT)departmental bulletin pape
2023/2024 Annual Cruise Report of the T/V Umitaka Maru Voyage : 【UM-22-05】 Cruise Report
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The Gaps between “New Migrant AMA Divers” and Local Communities: Challenges for Sustaining AMA Divers’ Culture
Full text link本稿では、2022年度から2023年度までの2年間、計7県8地域で行った聞き取り調査の結果をまとめ、新規就労海女（新人海女）の就業経路を類型化した上で、新人海女、特に新人移住海女の直面している就業上の問題と地域コミュニティ内の問題を明示し、そこから導かれる諸々の障壁について示唆する。そこでは、新人海女が、その就業に際して、1) 潜水技術、2) 収入、3) 兼業、という三つの「不足」とともに、地域コミュニティ内において、 1) 地縁、2) 血縁、3) 外部、という三つの「結びつき」を抱えており、それらの「不足」と「結びつき」が絡まり合って、新人移住海女と地域社会とのギャップが見られるのである。This paper summarizes the results of interviews conducted in eight regions in seven prefectures over a two-year period from 2022 to 2023. After categorizing the employment paths of newly employed female divers (new migrant AMA divers), the paper firstly identifies the employment problems which they face and the relationship problems within local communities where they live, and then suggests their barriers that can be derived from these problems. In particular, new migrant AMA divers face three “lacks” in their employment: 1) diving skills, 2) income, and 3) dual employment, as well as three “ties” within the local communities: 1) regional, 2) blood, and 3) external ones. Moreover, these “lacks” and “ties” are intertwined, resulting in the gaps between new migrant AMA divers and the local communities.小暮修三: 東京海洋大学学術研究院海洋政策文化学部門Shuzo KOGURE: Department of Marine Policy and Culture, Tokyo University of Marine Science and Technology (TUMSAT)departmental bulletin pape