To address the issue of low accuracy in ship trajectory prediction in complex navigable waters, this paper proposes a GRU-Attention-BiLSTM model for ship trajectory prediction. In the encoder part, the Gated Recurrent Unit (GRU) is employed to capture temporal features in trajectory sequences. The decoder adopts a Bidirectional Long Short-Term Memory Network (BiLSTM) integrated with an Attention mechanism to adjust the weights of data features. The model input is based on the longitude, latitude, speed and heading of the ship at the historical moment, and the ship density in the water area after median filtering smoothing is introduced as an additional feature. Using Automatic Identification System (AIS) data from the core port area of Ningbo-Zhoushan Port in March 2024, the model was trained and validated. Quantitative and qualitative comparisons with GRU, LSTM, Seq2Seq-LSTM, Attention-BiLSTM, and Transformer models demonstrate that the proposed model achieves superior prediction performance across different prediction durations and navigation scenarios.

With the rapid development of global shipping, port cargo volumes are increasing significantly, leading to growing issues of vessel congestion and delays, which in turn severely constrain port operations. In response to the challenges posed by surging cargo volumes, ship congestion, and aggravated pollution, this paper proposes a Time-Berth & Pollution (TB&P) model. The model takes the difference between the actual and expected time in port as the objective function, aiming to minimize operating costs and pollution emissions, subject to constraints related to time, space, and machinery/equipment. To solve the TB&P model, an improved version of the basic Beluga Whale Optimization (BWO) algorithm is developed, termed the Opposition Learning Beluga Whale Optimization (OBWO) algorithm. The feasibility and superiority of the proposed model and improved algorithm are verified through case data from a port. Results demonstrate that, compared with traditional models, the established model significantly reduces the extent of ship delays and mitigates water pollution in the port area. Furthermore, the proposed OBWO algorithm exhibits enhanced stability and accuracy relative to other selected algorithms.

To foster a new development paradigm, the Yangtze River Economic Belt serves as a crucial hub connecting the domestic and international circulations. As the leading port and core node of the Yangtze River Economic Belt, Shanghai Port's strategic role as one of the most critical infrastructure has become increasingly prominent. The Shanghai International Shipping Center is facing a bottleneck of spatial resource constraints in upgrading its service capacity. This paper evaluates port operational efficiency by constructing models for port service intensity, waiting probability, and queuing theory. It quantifies the impact of resource constraints using a ship loss rate model under different system capacities, while comparing development strategies of typical domestic and foreign ports to analyze the core challenges confronting the Shanghai International Shipping Center. Model analysis indicates that the structural contradiction between port service demand and spatial resource supply has become a key constraint on its high-quality development. Looking ahead, the expansion and upgrading of port-shipping resources and optimizing spatial resource allocation will enable the Shanghai International Shipping Center to effectively unleash the advantages of direct river-sea transportation, significantly improve port service capacity and the navigation efficiency of the Yangtze River Golden Waterway, and reduce the comprehensive logistics costs of the whole society. This development path will not only promote the green transformation and digital-intelligent upgrading of the shipping industry but also strengthen the country's supply chain security and expand high-level opening-up, laying a solid foundation for the long-term and sustainable development of the Shanghai International Shipping Center.

This study employs the MARIS model and a convective diffusion model to simulate the diffusion of nuclear wastewater released from Japan. Based on the simulation results, it proposes optimized methods for ballast water exchange to prevent the direct discharge of radioactive ballast water into ports, thereby mitigating potential threats to the ecological environment. The research focuses on the Fukushima nuclear incident and the subsequent continuous release of 1.3 million tons of nuclear wastewater into the ocean. Results indicate that radioactive substances are mainly concentrated in the surface layer of the ocean, with detectable enrichment of radioactive elements such as cesium in seawater and aquatic organisms near the Fukushima nuclear power plant. Consequently, ships operating near eastern Japanese ports are taking in ballast water contaminated with radioactive materials, including cesium-134 and cesium-137. Using a convective diffusion module, the study simulates the variation in radioactive substance concentrations during ballast water exchange at different distances, providing theoretical support for optimizing exchange strategies. The findings show that performing a secondary ballast water exchange more than 20 nautical miles from Japan's coast can reduce radioactive substance concentrations in ballast water to one ten-thousandth of the pre-exchange levels. The conclusions of this study can assist maritime regulatory authorities in formulating effective management measures, thereby contributing to the protection of marine ecosystems.

To achieve carbon neutrality, governments and enterprises are accelerating the decarbonization process in the shipping industry. This paper focuses on the Low-Carbon Maritime Supply Chain (LMSC), considering both government policies and consumers' green preferences. A two-stage Stackelberg game model between shipping companies and freight forwarders is developed to determine optimal pricing and carbon emission reduction strategies, while examining the impacts of carbon taxes, government subsidies, and consumers' green preferences on decision-making. The analysis yields three main findings: First, cooperation between freight forwarders and shipping companies maximizes overall profits for the LMSC; however, to achieve higher emission reduction levels, both parties should co-lead the supply chain. Second, government subsidies and enhanced low-carbon awareness produce dual effects: while they help reduce emissions and increase corporate profits, they may also raise TEU market prices for consumers under certain conditions. Third, although carbon taxes significantly improve the low-carbon performance of the LMSC, they reduce profits for all participants and increase TEU market prices.

To address the safety and economic requirements for ships navigating the complex ice environments of Arctic waters, this paper proposes a multi-objective improved Sparrow Search Algorithm (SSA) to optimize both wind resistance and ice resistance. The Risk Index Outcome (RIO), calculated by the Polar Operational Limit Assessment Risk Indexing System (POLARIS), and the safe water depth threshold are adopted as constraints to ensure navigation safety and mitigate the impact of resistance on navigation efficiency along Arctic routes. First, meteorological and ice data for the Arctic route are processed, and a grid environment map is constructed according to ship type. Second, safe navigable areas are identified, and a multi-objective function model is established. Finally, the improved sparrow search algorithm is applied to optimize the route and is compared with other typical path planning algorithms to verify the effectiveness and feasibility of the proposed method. The results indicate that the optimal path generated by the improved sparrow search algorithm, based on the multi-objective model of wind and ice resistance, can significantly reduce ship resistance during navigation-achieving a reduction of up to 10.9%. Moreover, there is no significant difference in path length or running time compared with other algorithms. This study provides an economical and reliable optimization solution for ship navigation in Arctic routes.

The arrival and handling times of vessels are subject to significant uncertainty. Triangular fuzzy numbers, characterized by upper and lower bounds and a most likely value, provide an effective means of representing such imprecise information. In this context, this paper first establishes a fuzzy integer programming model for berth allocation at container terminals, aiming to minimize the total departure delay time of vessels. An improved Multi-Verse Optimizer (MVO) algorithm is then proposed to solve the model, incorporating solution repair and breakout strategies. Comparative analysis shows that, in contrast to deterministic berth allocation schemes, the proposed fuzzy berth allocation approach demonstrates notable advantages in reducing total departure delay time and exhibits greater effectiveness in handling uncertainty. Moreover, the improved MVO algorithm achieves solution speed improvements of 59.9%, 44%, and 26.1% in small, medium, and large scale experiments, respectively, compared to the standard multi-verse optimizer. These results indicate that the proposed algorithm can efficiently solve the fuzzy integer programming model for berth allocation and offers valuable decision-making support for addressing berth allocation problems under fuzzy uncertainty.

To effectively identify vessels using fuel with excessive sulfur content, a reverse calculation method for determining fuel sulfur content was developed based on emission and diffusion characteristics. A Gaussian puff compensation model was applied to estimate the emission source strength of vessels from monitored SO₂ concentrations at designated points. In addition, a computational model for vessel fuel consumption was established using key vessel parameters, including the power and fuel consumption rates of main and auxiliary engines. The proposed method demonstrated superior performance compared to the mainstream carbon balance method in detecting vessels with non-compliant sulfur content, achieving detection and false detection rates of 86.60% and 2.06%, respectively. Over a 30-day continuous monitoring period, the fuel sulfur content of 2,743 vessels was successfully determined, representing an effective detection rate of 82.72%. Among these, 131 vessels were identified as potentially exceeding sulfur limits. Subsequent verification confirmed that 111 vessels used non-compliant fuel, resulting in an assessment accuracy of 84.73%. These findings demonstrate the method's capability to enable real-time monitoring of fuel sulfur content without requiring CO₂ concentration data.

This article firstly reviews the relevant background and process of revising China Maritime Code which is the first comprehensive and systematic revision in over thirty years. After elucidating the new historical mission of the Law in the new era, from the perspective of providing a solid legal safeguard for high-quality development of the shipping industry, it focuses on analyzing seven key institutional developments as follows: harmonizing domestic and international carriage of goods by sea rules, establishing the legal status of electronic transport records, regarding the port operators as actual carriers, prudently increasing limitation of liability amounts, clarifying the non-typical security attribute of ship finance leasing, improving the marine insurance rule system, and introducing countermeasure clauses. Finally, it proposes directional considerations regarding the implementation of new law, formulation of supporting rules, and future legislative development.

This article focuses on the significant revisions to the time limit system in the new Maritime Code of China, systematically examining the institutional restructuring in four key areas: the one-year time limit for the carriage of goods by sea, the recourse time limitation, special causes for the interruption of maritime time limitations, and the commencement of the time limitation for marine insurance claims. The research shows that the new Code has made important progress in maintaining the internationally accepted one-year benchmark, constructing a balanced bilateral time limit structure, appropriately broadening the causes for interruption, and unifying the commencement standard for insurance claims, thereby significantly enhancing the legal system's certainty and international harmonization. However, the new Code might face challenges in local adaptation, including the absence of an agreement-based extension mechanism, limited recourse time limitation relief space, and unclear special rules for liability insurance and subrogation. By analyzing the new legal system and evaluating its effectiveness and potential limitations, this article aims to provide response strategies for the shipping industry and judicial practice, promoting the continuous optimization of China's maritime legal environment.