https://i-jmst.vimaru.edu.vn/index.php/i-jmst/issue/feed 2026-03-30T00:00:00+00:00 Open Journal Systems https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/14 2026-01-26T08:05:02+00:00 Van Truong Nguyen nguyenvantruong@vimaru.edu.vn Dr. Xuan Long Nguyen nguyenxuanlong@vimaru.edu.vn Dr. Dang Thai Vu vudangthai@vimaru.edu.vn Dr. Hanh Hoang Thi Hong hanhhth.hh@vimaru.edu.vn

International Maritime Organization and countries have been paying special attention to Maritime Autonomous Surface Vessels (MASS). MASS is assessed to be able to bring benefits to the world maritime industry, but it also raises legal issues that need to be further studied and improved. Countries in the region have many activities related to MASS, typically issuing MASS standards, building MASS test sea areas, smart ports, sandboxes, etc. This study analyzes and evaluates in detail the policies, strategies and regulations of some typical countries in the region on MASS. In addition, the article also analyzes and synthesizes the current regulations of international conventions, whether or not they are suitable for MASS. From that analysis, the article presents experiences for Vietnam as well as other countries in the region to shorten the time to build and improve regulations for MASS. Develop action strategies for the construction, testing and development of MASS in practice. At the same time, the article also emphasizes the need to further strengthen regional cooperation in the ASEAN region.

2026-03-30T00:00:00+00:00 Copyright (c) 2026 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/16 2025-12-22T13:05:04+00:00 Dr. Huu Truong Vu truongvh.ctt@vimaru.edu.vn

The Multi-Objective Multi-Verse Optimizer (MOMVO) is applied to the structural optimization of a real-world berthing dolphin (BD). The BD structure is represented in SAP2000 using a detailed finite element model of piles and cap, with berthing and mooring loads defined in accordance with international guidelines. Two conflicting objectives are considered simultaneously: minimizing construction cost and minimizing the maximum structural displacement. Structural and geotechnical requirements are incorporated through a penalty-based constraint handling scheme to ensure compliance with Vietnamese design standards. The optimization results indicate that MOMVO generates well-distributed Pareto-optimal solutions that outperform the existing design. Relative to the baseline configuration, the optimal solutions achieve cost reductions of up to 70% while significantly decreasing structural displacement, with several compromise solutions available to balance both objectives. The results demonstrate that the proposed MOMVO–FEM framework provides practical and feasible design alternatives for improving the efficiency and safety of pile-supported marine structures.

2026-03-30T00:00:00+00:00 Copyright (c) 2026 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/22 2025-12-22T13:00:21+00:00 Thi Chang Tran changtt.ctt@vimaru.edu.vn

This study analytically investigates the wave reflection from a triangular floating platform in conbination with dual surface-piercing thin barriers over a sloped bottom using the eigenfunction matching method (EMM). The problem is formulated with linear water wave theory; eigenfunction expansions describe wave interactions across regions with varying bathymetry and boundaries. By imposing continuity of velocity potential and pressure at interfaces, a numerically solvable system is established. Reflection coefficients are analyzed with varying platform, barrier, and seabed parameters. Results show that barrier configuration and seabed slope significantly affect the reflected wave. The findings inform the design of structures for wave energy dissipation, platform protection, and nearshore barriers.

2026-03-30T00:00:00+00:00 Copyright (c) 2026 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/28 2026-01-09T08:16:51+00:00 Master Le Huy Vu huy.vule@vimaru.edu.vn Nguyen Thi Nha Trang trangntn@vimaru.edu.vn Master Nhung Nguyen Thi Cam nhungntc.ktb@vimaru.edu.vn

This paper studies the impacts of logistics performance on Vietnam’s export efficiency, using the stochastic frontier gravity model (SFGM). While the existing literature focused on the relationship between logistics and exports from a cost-reduction perspective, this paper scrutinizes the efficiency perspective of international trade. The analysis utilizes bilateral export data between Vietnam and its trading partners from 2005 to 2022. Greene’s True Random Effects (TRE) and True Fixed Effects (TFE) estimators are applied within the SFGM framework to address unobserved, time-invariant heterogeneity among trading pairs between Vietnam and its partners while enabling export efficiency to temporally change. The results show that both Vietnam’s and partners’ logistics performances significantly and positively affect export efficiency, diminishing the gap between actual bilateral export turnovers and the corresponding potential levels. The effect of Vietnam’s logistics performance is higher than that of its trading partners, indicating the greater importance of export logistics capabilities. These results indicate the crucial role of logistics in reducing “behind the border” constraints and provide a new insight into the logistics-trade relationship. The robustness of the findings is confirmed using instrumental variables regression. The policy implications include the necessity of consistent investments and improvements in logistics performance to overcome implicit trade barriers, further unlock Vietnam’s export potential, and facilitate its competitiveness in the international markets

2026-03-30T00:00:00+00:00 Copyright (c) 2026 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/32 2026-02-02T04:05:29+00:00 Van Minh Nguyen nvminh@dut.udn.vn Tung Nhu Vo vntung@dut.udn.vn Ngoc Hanh Nguyen Tran 107230085@sv1.dut.udn.vn Van Tu Mai 103220275@sv1.dut.udn.vn Thi Thu Quynh Nguyen quynhnt.dt@vimaru.edu.vn

The hydrodynamic resistance of container ships, especially at medium to high speeds, is greatly influenced by the bulbous bow, an essential design element. The KRISO Container Ship (KCS) has been widely used as a benchmark model because of its well-documented geometry and validated experimental data. A brief overview of the literature on the geometric effects and optimization of bulbous bows for KCS-type vessels is provided in this work. A comparative analysis is conducted among empirical prediction methods, CFD simulations, and experimental tests. Important geometrical factors are analyzed in relation to total and wave-making resistance, including bulb length, width, tip height, and volume ratio. The findings show that coordinated multi-parameter optimization, as opposed to discrete geometric adjustments, is necessary for efficient resistance reduction. A move toward integrated, data-driven, and multi-objective design techniques for energy-efficient bulbous bow development is reflected in recent developments in AI-assisted design, parametric modeling, and surrogate-based optimization.

2026-03-30T00:00:00+00:00 Copyright (c) 2026 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/35 2026-01-15T08:08:12+00:00 Assoc. Prof Van Nam Hoang namhv.vck@vimaru.edu.vn Minh Ngoc Nguyen nguyenminhngocsnu@snu.ac.kr

This paper employs advanced optimal techniques to design an acoustic lens composed of an anisotropic metamaterial. The structure of the optimized lens consists of random rigid scatters embedded in a matrix, in which the sizes of the scatters are treated as design variables of the optimization problem. The numerical examples demonstrate that the optimized lens can focus plane waves onto a focal region of subwavelength scale. At the focal distance of , the optimized design achieves subwavelength focusing, characterized by a full width at half maximum (FWHM) of, along with a high sound pressure level (SPL) of 14.7 dB at the focal point. This performance surpasses the diffraction limit, owing to the enhancement of evanescent waves through multiple scattering. Moreover, the optimized lens can offer a potential for a wide operating frequency range.

2026-03-30T00:00:00+00:00 Copyright (c) 2026 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/43 2026-02-06T04:05:05+00:00 Tat Minh Huynh minhht@vimaru.edu.vn Dr. Minh Duc Nguyen ducnguyen@vimaru.edu.vn

Decision 749/QD-TTg identifies logistics as a priority sector in Vietnam’s digital economy strategy toward 2030, placing increasing pressure on seaports to pursue digital transformation. Assessing digital maturity in this setting, however, remains difficult. Most international port digital maturity frameworks are developed for environments characterized by advanced infrastructure, automated data systems, and stable governance arrangements—conditions that are only partially present in Vietnam. This study proposes the Vietnam Port Digital Index as a conceptual readiness framework designed for emerging economies. The framework is developed through a three-stage process comprising literature-informed synthesis, conceptual clustering of capability pillars, and contextual screening against domestic governance and data constraints. Rather than treating technology adoption as a sufficient indicator of maturity, the Vietnam Port Digital Index explicitly incorporates organizational capacity and policy readiness as core analytical dimensions. The framework therefore provides a context-sensitive structure for understanding digital transformation in Vietnamese seaports and establishes a foundation for subsequent empirical operationalization and quantitative assessment.

2026-03-30T00:00:00+00:00 Copyright (c) 2026 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/44 2026-01-29T15:30:23+00:00 Quyen Nguyen Huu quyennh.ddt@vimaru.edu.vn Cuong Nguyen Hung cuongnh.ddt@vimaru.edu.vn My Truong Cong mytc.ddt@vimaru.edu.vn

This paper explores the problem of trajectory tracking control for Underactuated Surface Vessels (USVs) subject to unknown environmental disturbances and other uncertainties. The proposed controlled system consists of an Adaptive Sliding Mode Control (ASMC), an High-Order Extended State Observer (HO-ESO), and an energy-optimal Thrust Allocation (TA) algorithm between the propeller and the rudder. An HO-ESO is introduced to estimate unmeasured system states and unknown external disturbances, enhancing the control system’s sustainability. Moreover, to improve the precision in trajectory tracking and mitigate the conventional sliding mode control’s chattering phenomenon, an adaptive control law is designed to dynamically adjust control gains. Furthermore, unlike conventional control methods, input control signals are typically assumed to be ideal. An energy-optimal thrust allocation algorithm is developed to convert control signals from the controller into practical reference commands for the actuators. By establishing a nonlinear optimization problem, the proposed TA scheme helps to reduce the total amount of energy consumption while ensuring physical actuator constraints and maintaining satisfactory trajectory tracking performance. This paper also performs a stability analysis based on Lyapunov theory, which proves that all tracking errors in the closed-loop system are bounded and stable. Simulation studies, which are conducted in the Matlab-Simulink application, has validated the superiority of the proposed integrated controller, in terms of its tracking accuracy, disturbance rejection capability, and energy efficiency compared with existing methods.

2026-03-30T00:00:00+00:00 Copyright (c) 2026 International Journal of Marine Science and Technology