Bias Estimation for Low-Cost IMU Including X- and Y-Axis Accelerometers in INS/GPS/Gyrocompass

Inertial navigation systems (INSs) provide autonomous position estimation capabilities independent of global navigation satellite systems (GNSSs). However, the high cost of traditional sensors, such as fiber-optic gyroscopes (FOGs), limits their widespread adoption. In contrast, micro-electromechanical system (MEMS)-based inertial measurement units (IMUs) offer a low-cost alternative; however, their lower accuracy and sensor bias issues, particularly in maritime environments, remain considerable obstacles. This study proposes an improved method for bias estimation by comparing the estimated values from a trajectory generator (TG)-based acceleration and angular-velocity estimation system with actual measurements. Additionally, for X- and Y-axis accelerations, we introduce a method that leverages the correlation between altitude differences derived from an INS/GNSS/gyrocompass (IGG) and those obtained during the TG estimation process to estimate the bias. Simulation datasets from experimental voyages validate the proposed method by evaluating the mean, median, normalized cross-correlation, least squares, and fast Fourier transform (FFT). The Butterworth filter achieved the smallest angular-velocity bias estimation error. For X- and Y-axis acceleration bias, altitude-based estimation achieved differences of 1.2 × 10−2 m/s2 and 1.0 × 10−4 m/s2, respectively, by comparing the input bias using 30 min data. These methods enhance the positioning and attitude estimation accuracy of low-cost IMUs, providing a cost-effective maritime navigation solution.公開日: 2025-02-21journal articl

風力下におけるタグボートを用いた自動着桟システムの研究

東京海洋大学修士(海洋科学)東京海洋大学修士学位論文 2024年度(2025年3月) 海運ロジスティクス 修士 第4616号指導教員: 岡崎忠胤全文公表年月日: 2025-06-13master thesi

Preparation, isolation and identification of novel antioxidant peptides from extruded-expanded tuna bone meal

Tuna bone, a by-product of fish processing, is rich in protein but often underutilized. This study aimed to enhance its bioavailability by preparing nanoscale tuna bone meal through extruded-expanded technology and subsequently hydrolyzing it with proteases to produce antioxidant peptides. The extruded-expanded tuna bone meal (EE-FB) exhibited a significantly reduced average particle size (296.45 nm) compared to non-extruded-expanded samples (982.85 nm). This indicates that extruded-expanded treatment has a significant effect on the particle size change of tuna bone meal, which helps to ensure sufficient contact between tuna bone meal and protease during the enzymatic hydrolysis and improve the enzymatic hydrolysis rate. Optimal enzymatic hydrolysis conditions were determined using response surface methodology: dual-enzyme (trypsin and alcalase) dosage of 4600 U·g−1, solid-liquid ratio of 1:6.90 (w/v), and hydrolysis time of 4.10 h, achieving a degree of hydrolysis (DH) of 45.06 %. The hydrolysate was fractionated by ultrafiltration, further purified by Sephadex G-15 gel chromatography, and identified six novel peptides: VQQPL, VTDLN, AGPQGP, APDPFR, GDRAFLI, and SGPAGPA by LC-ESI-MS/MS. Six novel peptides have shown the ability to scavenge free radicals (DPPH, superoxide, hydroxyl). The molecular weight of the six new peptides was <1000 Da and they exhibited antioxidant activity. This may be attributed to the hydrophobic and alkaline amino acids contained in the peptide. This study provides a rapid and efficient method for producing bioactive peptides from tuna bone, with potential applications in functional food and pharmaceutical production.公開日: 2025-06-20journal articl

コイ稚魚の成長及び健康状態に及ぼすシラス及びグレープフルーツ精油の影響

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716号指導教員: 舞田正志全文公表年月日: 2025-06-16doctoral thesi

An Empirical Analysis of the Linkages between Green/Blue Bonds and Social Impacts

近年、（企業や大学を含む）日本の様々な組織が、環境債（グリーンボンド）及びブルーボンドを発行し、自然資本への取り組みを加速させている。ブルーボンドは、水資源や海洋関連事業に特化した環境債を指す。本稿では、1,203社の最新の日本企業のデータに基づき、（潜在変数である）企業の「社会インパクト創出力（社会性）」と、複数の観測変数との繋がりに着目し、分析を行った。変数は、以下の通りである［環境債、CSV（共通価値の創造）事業、CE（サーキュラー・エコノミー：循環型経済社会）の取り組み、SDGs、ステークホルダー・ダイアログ（機関投資家を含む利害関係者との対話）、国際イニシアティブ（SASBスタンダード、TNFD、RE100）］。さらに、8つの産業を対象に、2種類の潜在変数（社会性と経済性）の繋がりについても、構造方程式モデリング（SEM）を用い考察を加えた。その結果、6つの産業において有意な正の相関（社会性と経済性の両立）がみられた。特に食品関連産業では、社会性と観測変数の「環境債及びブルーボンド等」との間で、有意な強い正の関連性が示された。Various Japanese organizations, including companies and universities, have begun issuing green bonds and blue bonds to accelerate their environmental initiatives. Green bonds are designed to support projects related to climate change and the environment. Similarly, the aim of blue bonds is to facilitate projects addressing problems regarding water resources and marine biodiversity. Based on an examination of 1,203 Japanese companies, this study explores the relationship between “social/economic impacts” and observed variables, such as Green/Blue Bonds, CSV (Creating Shared Value) Projects, CE (Circular Economy) Initiatives, SDGs (The Sustainable Development Goals), Multi-Stakeholder Dialogues, and Global Environmental Initiatives (The SASB Standards, TNFD, and RE100), etc. In addition, Structural Equation Modeling (SEM) was used to analyze the links between the latent variables (“Social Impact” and “Economic Performance”) in 8 industries. The findings showed that there were statistically significant correlations between the two latent variables in 6 out of 8 industries. Green/blue bonds and green loans, especially for companies in the food industry, play an important role in achieving strong social impacts.近藤久美子: 東京海洋大学海の研究戦略マネジメント機構Kumiko KONDO: Office of Management and Strategy for Marine Studies (MS-Square), Tokyo University of Marine Science and Technologydepartmental bulletin pape

Development of a Method for in vivo Direct Monitoring of Stored Fat Burning Using Stable Isotope-labeled Fatty Acids

We developed a novel approach for direct and rapid evaluation of the fat-burning effects of various food ingredients in vivo. Male ICR mice were fed a diet containing stable isotope-labeled palmitic acid, and fat oxidation was quantified by measuring the production of labeled carbon dioxide (13CO2) generated during β-oxidation. By evaluating the 24-h fat burning profile, we demonstrated the immediate fat-burning effect of caffeine and the gradual fat-burning effect of curcumin. This methodology allows fat-burning-specific detection rather than fat absorption inhibition, thereby providing a powerful tool for comparing fat-burning effects of different food components in vivo.公開日: 2025-04-01journal articl

Recent Achievements of the OQEANOUS Plus Program＊6 and Its Impact on Global Education at Tokyo University of Marine Science and Technology

本稿は、本学が2021年度から実施する、日中韓・ASEAN大学間の海洋分野の高度専門職業人育成を目指す学生交流事業「オケアヌスプラス」が本学のグローバル教育に与えた新たな展開について考察した。第一に、オンラインを活用した導入プログラムへの参加が、実渡航を伴う中長期留学の参加に繋がる「段階的な留学モデルコース」を確立し、学生が卒業や就職活動に支障を感じることなく、外国の大学での教育研究による単位互換・学位取得も可能とし、学生の流動性を高められた。第二に、多様なアジアの大学間で、国際的な基準に配慮した質の保証を伴う単位互換ガイドラインCTSEAAを制定した。第三に、オンラインの活用がプログラムの教育効果を高め、コミュニケーションの機会を増やす手段として有効であること、そして第四に、教職員間ネットワークの強化が事業実施の重要な基盤となることを示した。また、初めての修了生アンケート結果の分析から、オケアヌスプラスの教育効果及び課題を確認できた。引き続き、事業最終年度（2025年度）に向けて、特に、留学による学びの可視化に取り組み教育効果を検証し、本学のグローバル教育に資する成果を目指す。This report examines the impact of the OQEANOUS Plus Program (OPP), a student exchange framework with quality assurance established between seven leading marine universities in Japan, China, ROK and ASEAN, on global education initiatives at Tokyo University of Marine Science and Technology. The OPP has demonstrated significant influence in four primary areas: (1) the provision of online and hybrid short-term introductory courses has established a phased study abroad model, leading students progressively engage in longer-term on-site exchange courses enabling seamless credit transfers and double-degree opportunities, without imposing any career constraints; (2) CTSEAA was established and authorized as a fundamental guideline on credit transfers and academic record conversions, ensuring quality assurance in international student exchanges; (3) the strategic integration of online platforms has enhanced both the quality of education and cross-cultural communication opportunities; and (4) building a strong professional network among academic and administrative personnel is the key to the successful execution of the OPP. Furthermore, post-program student surveys have revealed not only positive educational outcomes but also areas that require further attention, offering valuable insights for the future evolution of the program.中馬愛: 東京海洋大学学務部国際・教学支援課Ai CHUMAN: Academic Support and International Division, Tokyo University of Marine Science and Technology (TUMSAT)八田育美: 東京海洋大学学務部国際・教学支援課Ikumi HATTA: Academic Support and International Division, Tokyo University of Marine Science and Technology (TUMSAT)加賀絵里奈: 東京海洋大学学務部国際・教学支援課Erina KAGA: Academic Support and International Division, Tokyo University of Marine Science and Technology (TUMSAT)飯野知宏: 東京海洋大学学務部教務課Tomohiro IINO: Academic Affairs Division, Tokyo University of Marine Science and Technology (TUMSAT)申蓮花: 東京海洋大学学務部国際・教学支援課Lianhua SHEN: Academic Support and International Division, Tokyo University of Marine Science and Technology (TUMSAT)小山裕子: 東京海洋大学学務部国際・教学支援課Yuko OYAMA: Academic Support and International Division, Tokyo University of Marine Science and Technology (TUMSAT)呉海云: 東京海洋大学学術研究院海洋環境科学部門Haiyun WU: Department of Ocean Sciences, Tokyo University of Marine Science and Technology (TUMSAT)廣野育生: 東京海洋大学学術研究院海洋生物資源学部門Ikuo HIRONO: Department of Marine Biosciences, Tokyo University of Marine Science and Technology (TUMSAT)舞田正志: 東京海洋大学Masashi MAITA: Tokyo University of Marine Science and Technology (TUMSAT)departmental bulletin pape

Custom-made medium approach for effective enrichment and isolation of chemolithotrophic iron-oxidizing bacteria

Chemolithotrophic 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

GNSSとIMU統合に基づくスマートフォン測位の最適化とAIを利用した静止判定

東京海洋大学修士(工学)東京海洋大学修士学位論文 2025年度(2025年9月) 海運ロジスティクス 修士 第4664号指導教員: 久保信明全文公表年月日: 2025-12-18master thesi

Relationship between escape behavior of juvenile Pacific bluefin tuna and bag net shape of set net

定置網におけるクロマグロの漁獲量の調整方法の開発は課題の1つである。その調整方法の1つとして網から自然逃避しやすいと言われているクロマグロの行動特性を利用することが考えられる。そこで，クロマグロ小型魚の箱網外への逃避と，漁場の流速，箱網底面の深度，経過時間，尾叉長の関係を調査した。その結果，潮流による箱網底面の吹き上がりがクロマグロの自然逃避を促すことがわかった。箱網深度よりも定置網漁業での利用機会が多い潮流の情報は，クロマグロ小型魚の漁獲コントロールに役立つ可能性がある。Controlling the catch of Pacific bluefin tuna in set nets is an important issue in stock management of the species in order to comply with quotas under international regulations. Bluefin tuna, once inside set net gear, tend to escape naturally due to the structure of set net gear before landing. Investigating the shape of the set net depending on oceanographic conditions, which are relevant for natural escape, may yield clues for controlling the catch. We therefore studied the relationship between fishing conditions and escape behavior of Pacific bluefin tuna by a tagging experiment. The test results were analyzed by a generalized linear model and the best model was selected by Akaike’s information criterion. The explanatory variables were body length of Pacific bluefin tuna, tidal current velocity, bottom of the minimum bag net depth, and elapsed time. The results showed that escape of Pacific bluefin tuna was affected by minimum bag net depth and tidal current speed, because the tidal current raised the bag net bottom and reduced the swimming space for the tuna. These results may be useful for future resource management of Pacific bluefin tuna in set nets.公開日: 2025-07-10journal articl