https://i-jmst.vimaru.edu.vn/index.php/i-jmst en-US Tue, 30 Dec 2025 00:00:00 +0000 OJS 3.2.1.1 http://blogs.law.harvard.edu/tech/rss 60 https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/21 Accurate forecasting of project cost and schedule is essential for effective project control and decision-making. Traditional earned value management (EVM) offers a deterministic view of performance but fails to capture the uncertainties inherent in dynamic project environments. This study introduces a probabilistic forecasting approach that integrates EVM with Monte Carlo simulation to model the stochastic behavior of cost and schedule performance indices. Two hypothetical project scenarios are analyzed to demonstrate the method’s applicability: one characterized by cost efficiency but schedule delay, and another by schedule progress but cost overrun. In both cases, cumulative project data—planned value, earned value, and actual cost—are used to generate probabilistic estimates of cost and duration at completion, along with confidence intervals and risk profiles. The results show that the proposed framework produces smoother and more credible forecasts while quantifying the likelihood of budget and schedule outcomes. This enhances the interpretability and reliability of EVM by linking performance trends with uncertainty, offering project managers deeper insights for proactive and risk-informed decision-making. Kim Son Luong, Nhu Son Doan Copyright (c) 2025 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/21 Tue, 30 Dec 2025 00:00:00 +0000 https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/11 The paper evaluates the stress-strain relationships of different structural element groups of ship structures subjected to longitudinal bending moments at the ultimate limit state (ULS). The incremental-iterative method proposed by the International Association of Classification Societies (IACS) is applied. In this method, the hull cross-section is divided into three groups of structural elements, each assigned to one of six common failure modes. Bulk carriers (BCs) are employed to illustrate the calculation results. Accordingly, the paper presents the stress-strain curves of the different structural element groups, as well as the stress and strain experienced by each structural element at the ULS under hogging and sagging conditions. One notable finding is that the sagging condition generates higher stresses in the ship structure compared to the hogging condition. The top-side tank region experiences the highest stress levels, reaching the material’s yield stress when the ship approaches its ultimate longitudinal bending capacity. Additional discussions are also provided in this paper. Van Tuyen Vu, Quang Quan Do, Huy Chinh Cu, Huy Vu Nguyen Copyright (c) 2025 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/11 Tue, 30 Dec 2025 00:00:00 +0000 https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/24 This study employed the OpenFOAM framework coupled with the olaFlow solver to simulate wave-driven overland flows in an idealized coastal community, with a particular focus on the validation of the numerical model as the first preliminary research study. A series of large-scale 1:16 laboratory experiments in a three-dimensional wave basin, conducted under a wide range of water levels, wave conditions, and structural configurations, including a seawall (SW) and a submerged breakwater (SB), served as the benchmark for validation. Model performance was assessed by comparing time series of offshore and onshore free-surface elevations, horizontal velocities, and hydrodynamic loads (forces and pressures) on building arrays in an idealized constructed environment. Furthermore, the validation results exhibited a strong agreement between measured and simulated hydrodynamic and loading variables, with normalized root-mean-square errors (NRMS) less than 15.32% and an index of agreement (IA) up to 0.95. These findings establish that the olaFlow solver can reliably reproduce time series of hydrodynamic parameters, providing a robust foundation for subsequent evaluation of coastal flooding mitigation strategies. Van Hai Dang, Van Khoi Pham, Sungwon Shin Copyright (c) 2025 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/24 Tue, 30 Dec 2025 00:00:00 +0000 https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/19 The urgent demand to reduce carbon emissions from the cement and concrete industry has motivated the development of carbon-negative technologies. This study provides a comprehensive assessment of potential solutions for Vietnam’s infrastructure, focusing on two key applications: precast revetment blocks for coastal dikes and lightweight foam concrete for highway embankments. For precast blocks subjected to 2-hour CO2 curing, an average uptake of 70 kg CO2/m3 was recorded, with net sequestration of 62.6 kg CO2/m3 after subtracting curing-related emissions. At the project scale of 1,000 m3, this corresponds to approximately 62-65 tons of CO2 permanently stored. For CO2-foam concrete, the average uptake reached 87 kg CO2/m3, equivalent to 87 tons per 1,000 m3. Incorporating nano-silica or nano-CaCO3 increased compressive strength by 30-35% and enhanced CO₂ fixation by 5-10%, enabling a reduction of 5-8% in cement content while maintaining required design strength. When compared to baseline C30 concrete (~295 kg CO2/m3), these results highlight the potential to achieve net-negative emissions. The findings confirm that the deployment of carbon-negative concrete in Vietnam’s coastal and highway infrastructure could significantly contribute to the Net Zero 2050 target while providing durability and mechanical performance benefits. Thi Ly Pham, Phan Anh Nguyen Copyright (c) 2025 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/19 Tue, 30 Dec 2025 00:00:00 +0000 https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/17 Conventional mooring line design for floating structures often relies on empirical or trial-and-error methods, leading to inefficient material use and increased costs. This study proposes a multi-objective optimization framework using the Multi-Objective Particle Swarm Optimization (MOPSO) algorithm to design a single mooring line, with a novel emphasis on the sinker’s mass. The approach simultaneously minimizes the mooring line weight and sinker mass while satisfying strength, stability, and seabed contact constraints. The resulting Pareto front reveals a clear trade-off between these objectives, with an optimal "knee point" offering a balanced design. Compared to empirical designs, the optimized configuration reduces mooring line weight by 15.9% and sinker mass by 22.3%, demonstrating significant material and cost savings. This method provides a systematic and efficient tool for enhancing the design of mooring systems in offshore engineering applications. Xuan Truong Nguyen, Quoc Hoan Pham Copyright (c) 2025 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/17 Tue, 30 Dec 2025 00:00:00 +0000 https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/18 This paper presents a methodology for determining the wave surface profile and the velocity components of water particles from the wave spectrum of a random sea state to calculate the loads acting on the buoy. For the calculation of mooring lines with attached weights under random loads, the finite element method (FEM) is applied. The parameters of the governing dynamic equations are identified, the Newmark method is used for time integration, and a computational program is developed. The program is verified by comparing the results of the static problem with the dynamic problem under constant loading, demonstrating the correctness of the algorithm and computation. The program is then applied to calculate mooring lines with attached weights for an actual navigational buoy subjected to wind, current, and random wave loads, demonstrating the practical applicability of the proposed approach. Van Tuan Dao, Thi Diem Chi Nguyen Copyright (c) 2025 International Journal of Marine Science and Technology https://i-jmst.vimaru.edu.vn/index.php/i-jmst/article/view/18 Tue, 30 Dec 2025 00:00:00 +0000