Non-Destructive Integrity Assessment of Austenitic Stainless-Steel Membranes via Magnetic Property Measurements

Abstract This study proposes a novel non-destructive methodology for assessing structural integrity in liquefied natural gas (LNG) carrier cargo containment systems (CCSs), addressing limitations of conventional inspection techniques like visual inspection and vacuum box testing. The method leverages strain-induced martensitic transformation (SIMT) in austenitic stainless steel (SUS304L), widely used in CCS membranes, quantifying magnetic permeability […]

Scheduling optimization of hull block assembly line using constraint programming and discrete-event simulation

Abstract Scheduling of a block assembly line in a shipyard is commonly known as the Permutation Flow-shop Scheduling Problem (PFSP) in Operation Research (OR), which has been extensively studied in various papers since the 1950s. However, existing solutions often involve simplifying real-world problems with certain assumptions, limiting their practical applicability. In recent times, Constraint Programming […]

Framework for state features design in job shop scheduling with deep reinforcement learning: Beyond empirical approaches

Abstract This paper addresses a critical research gap in applying deep reinforcement learning to job shop scheduling problems by focusing on state feature design, which has been largely treated as an empirical matter. We present three key contributions: (1) a state feature design framework for reinforcement learning application in scheduling domain: dynamics equation (DE) and predicting […]

Analysis of sortie generation on an aircraft carrier with discrete event simulation

Abstract The sortie generation rate (SGR), defined as the number of sorties an aircraft carrier can launch and recover within a specified time, is a key metric for evaluating operational capacity. However, accurately predicting SGR is challenging due to complex deck constraints, bottlenecks, and maritime conditions. This study proposes a discrete event simulation framework incorporating […]

Aggregate nesting: Transforming multi-material dynamic allocation for cost-effective manufacturing

Abstract Multi-material nesting optimization is a critical challenge in industries such as shipbuilding, where both cost-efficiency and adaptability are essential. Traditional single-material nesting approaches often fail to address the complexities of dynamic and large-scale production environments. This study proposes the Aggregate Nesting (AN) methodology, which dynamically allocates items across multiple plates to optimize material yield […]

Accounting for wave-induced environmental uncertainty in CO₂ emission predictions for maritime operations

Abstract Reliable estimation of greenhouse gas (GHG) emissions from maritime operations is vital for understanding their environmental impact and supporting international decarbonization policies such as those mandated by the International Maritime Organization (IMO). However, current CO₂ prediction methods often overlook environmental uncertainties—particularly wave-induced resistance—which significantly influence engine performance and emissions in real-world conditions. This study […]

Development of a methodology for evaluating the susceptibility of naval surface ships based on naval engagement simulation

Abstract This study presents a simulation-based methodology for evaluating the susceptibility of naval surface ships in realistic engagement environments. Susceptibility is a critical indicator of ship survivability, yet most prior assessments have relied on deterministic or static probabilistic chains that assume fixed probabilities for detection, tracking, and interception. Such approaches fail to capture the dynamic […]

From material characterization to process simulation: Performance evaluation of amine-infused resins for CO2 capture

Abstract Selective capture of CO2 using solid CO2 sorbents provides an effective solution for a simplified CO2 capture process, however it demands high CO2 capture performance with low regeneration energy. A solid adsorbent incorporating diethanolamine (DEA) within a cross-linked polystyrene based porous ion-exchange resin was synthesized. DEA was incorporated into the channels of the resin by infusion, denoted as […]

Hybrid approach for enhanced wave spectrum estimation integrating semi-supervised learning and wave buoy analogy

Abstract This study presents an innovative approach for estimating wave parameters by integrating a modified wave-buoy analogy with semi-supervised learning techniques, utilizing ship motion responses. The proposed methodology employs a two-step method to accurately determine wave parameters including incoming wave direction, spreading strength, height, and period. In the first step, the primary incoming wave direction […]