December 2024
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8 Reads
Journal of Marine Engineering & Technology
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December 2024
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8 Reads
Journal of Marine Engineering & Technology
December 2024
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6 Reads
ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems Part A Civil Engineering
November 2024
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36 Reads
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1 Citation
IEEE Transactions on Intelligent Transportation Systems
The field of ship autonomous navigation has always garnered significant interest due to its future development potential for intelligent ships and unmanned ships. While there has been extensive research on autonomous navigation in open waters, less focus has been given to coastal waters due to the complexity of the environment and traffic flow. In order to resolve this problem, the dynamic adaptive decision-making method for ship autonomous navigation in coastal waters is presented. A digital twin environment model tailored to the characteristics of coastal waters has been developed, which can dynamically replicate the current ship navigation environment by incorporating multi-source heterogeneous information from ship equipment. The autonomous navigation decision-making method is obtained by integrating an Improved Velocity Obstacle (IVO) for ship collision avoidance and a Line of Sight (LOS) algorithm for ship trajectory tracking. Moreover, a time-rolling algorithm is employed to facilitate specific navigation decision-making in time-varying environments and to account for the uncertainty of target ship motion over time. This comprehensive algorithm has been tested and validated in two different scenarios. The results demonstrate that the proposed navigation decision-making method is reasonable and effective for the ship navigating in the coastal water, particularly in multi-ship encounter situations of target ships suddenly altering course or changing speed.
June 2024
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21 Reads
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1 Citation
ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems Part A Civil Engineering
May 2024
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24 Reads
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3 Citations
Journal of Marine Science and Engineering
Sorting out the requirements for intelligent functions is the prerequisite and foundation of the top-level design for the development of intelligent ships. In light of the development of inland intelligent ships for 2030, 2035, and 2050, based on the analysis of the division of intelligent ship functional modules by international representative classification societies and relevant research institutions, eight necessary functional modules have been proposed: intelligent navigation, intelligent hull, intelligent engine room, intelligent energy efficiency management, intelligent cargo management, intelligent integration platform, remote control, and autonomous operation. Taking the technical realization of each functional module as the goal, this paper analyzes the status quo and development trend of related intelligent technologies and their feasibility and applicability when applied to each functional module. At the same time, it clarifies the composition of specific functional elements of each functional module, puts forward the stage goals of China’s inland intelligent ship development and the specific functional requirements of different modules under each stage, and provides reference for the Chinese government to subsequently formulate the top-level design development planning and implementation path of inland waterway intelligent ships.
April 2024
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10 Reads
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2 Citations
Applied Ocean Research
October 2023
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32 Reads
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9 Citations
Ocean Engineering
July 2023
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68 Reads
Applied Sciences
A maneuvering decision-making model based on time series rolling and feedback compensation methods is proposed to solve the problem of high traffic risk in Chengshantou traffic separation scheme (TSS) waters. Firstly, a digital traffic environment model suitable for the TSS waters is proposed. Secondly, a navigation risk identification method in these waters is constructed based on the digitized traffic environment and situation identification model in the Chengshantou TSS waters. Thirdly, considering the requirements of the rules and good seamanship, minimum course altering is obtained by combining the collision avoidance mechanism. Lastly, a maneuvering decision-making model in the TSS waters based on time series rolling and feedback compensation methods is developed. The simulation results show that the ship can correctly identify the collision risk and appropriately obtain maneuvering decisions, and can resume the planned route under the premise of ensuring safety. When the target ships alter course or change speed, the ship can also make adaptive maneuvering decisions. In summary, the proposed method meets the requirement of safe navigation in Chengshantou waters and provides a theoretical basis for the realization of intelligent navigation in waters similar to TSS.
January 2023
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39 Reads
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28 Citations
Ocean Engineering
Ship autonomous collision avoidance has attracted increasing attention in recent years. However, more attention is paid to the scenario in which the target ship keeps its course and speed. Less attention is paid to the development of a collision avoidance decision-making system under the uncertainty of the target ship's movement in a complex multi-ship encounter situation. Based on the idea of model predictive control (MPC), this paper proposes an autonomous ship collision avoidance decision-making system (CADMS) suitable for the uncertainty of ship motion. The CADMS includes four modules: collision risk analysis module, control and execution module, ship trajectory prediction module and collision avoidance decision-making model. The proposed model can be implemented in the collision avoidance decision-making system for safe navigation or it can be included in the ship autonomous navigation process. The decision-making model is achieved from a risk identification-motion prediction-ship control-scheme implementation perspective, and the dynamic and uncertainty features of the ship action (i.e., alter course or change speed) are considered in the modelling process. The real-time rolling update of ship collision avoidance decisions is realised based on the time series rolling method. Four scenarios are designed to demonstrate the collision avoidance decision-making system's performance. The results show that the proposed collision avoidance decision-making system is a reasonable and effective system for collision avoidance, particularly in multi-ship encounter situations of target ships suddenly altering course or change speed.
November 2022
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48 Reads
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4 Citations
Journal of Marine Science and Engineering
There is a need to study the evolutionary laws of the risks in the navigation environments of complex marine areas. This can promote shipping safety using an early-warning system. The present study determines shipping flows and meteorological conditions in a marine area on the basis of meteorological and automatic identification system (AIS) data. It also determines the uncertainty evolution law of the navigation environment’s influencing factors. Moreover, a navigation risk evolution system for ships in complex marine areas was developed. A case study was carried out in a coastal area of China on the basis of the determined evolutionary laws. Evolution in the navigational environment risk within the case study area was analyzed. The results showed that the hydrometeorology wind factor has the greatest impact on the risk of ship collisions. This work was not only able to show advances in navigational collision environmental evolution laws but also provides a theoretical reference for the evaluation and early warning of risks in shipping environments.
... For a balance between the need for timely decision-making and the reliability of predictions, a 15-minute prediction time is decided based on the environmental conditions, traffic density, and so on (Gao and Zhang 2024). The prediction ensures that our model is both practical and relevant to the operational realities of maritime navigation, providing robust support for the effective avoidance of collisions and navigational hazards (Zhao et al. 2024). ...
November 2024
IEEE Transactions on Intelligent Transportation Systems
... On one hand, ship electronic systems have long relied on specialized industry protocol standards [2]. Although these standards offer a high degree of standardization, the protocols are ill-suited to meet the connectivity requirements of modern, general-purpose intelligent devices [3]. During the process of ship digitization, intelligent systems need to integrate diverse data and functional modules. ...
May 2024
Journal of Marine Science and Engineering
... IZZ and JZZ denote the moments of inertia and additional inertia, respectively. For a detailed understanding and calculation of these variables, references [15], [16], and [17] should be consulted. ...
April 2024
Applied Ocean Research
... In the context of ship trajectory prediction, the future motion characteristics of a ship are intricately linked to its historical and present motion patterns. Within the framework of long short-term memory (LSTM), the historical motion patterns of a ship can be encapsulated through cell states, thereby establishing a long-term memory [13][14][15][16][17]. The LSTM architecture employs sigmoid and tanh activation functions for its two input gates, where input data passes through these gates to extract features that are subsequently directly combined and fed into the cell state [18]. ...
January 2023
Ocean Engineering
... This relationship likely corresponds to the cyclical rise and fall of temperatures across seasons, with SST peaking in summer and reaching lower levels in winter. Additionally, the moderate positive correlation between SST and SSH (0.42) may reflect a trend of rising sea surface height as temperatures increase, which could be partially attributed to thermal expansion effects [37]. When water temperature rises, ocean water volume expands, leading to an increase in sea surface height. ...
October 2023
Ocean Engineering
... Thus, flange and shaft can be connected by using chamfers as shown in Fig. 1a. Due to the frequent changes of winds, waves and currents and other geographical environment and navigational status of ships during sailing [1], the main shaft could be subjected to cyclic torsional and bending loads, and the structural inhomogeneity could also lead to the occurrence of elastic stress concentration effects. This main shaft with one notch for research purpose can be shown in Fig. 1b, T is the torque, D is diameter of cross section of smooth part of the specimen, d is diameter of cross section of notch part, h is the radius difference of cross section between smooth part and notch part, and ρ is curvature radius of the u-notch. ...
November 2022
Journal of Marine Science and Engineering
... To further narrow down the feasible solution space, Zheng et al. [26] introduced multiple constraints in their method, improving the accuracy of the collision avoidance strategy. Zhang et al. [27] proposed a real-time collision avoidance method for autonomous ships based on an improved velocity obstacle algorithm and a gray cloud model, incorporating COLREGs. ...
October 2022
... Characteristics such as ship maneuverability, ship size and ship type are not considered in this paper. Nevertheless, these factors are known to play an important role in collision avoidance under certain conditions Zhao et al., 2022). Furthermore, more advanced methods for assessing the risk of collision between two ships have been proposed, see e. g. ...
September 2022
Applied Sciences
... The engine system contains many combustible materials, such as fuels or chemicals, which can potentially be ignited. Any thermal source that ignites these materials can cause fire accidents [6][7][8]. Shao et al. [9] identified hazard identification as an essential stage in the unique development of a ship. It was found that the most significant risk factors in the engine system were fire accidents caused by fuel leakage from connecting valves or flanges. ...
September 2022
Ocean Engineering
... The CRI is a crucial physical quantity that quantifies the urgency of avoiding collisions between ships, which is determined by various factors such as the relative velocity, bearing, and distance between the two ships (Zhang et al. 2022). The CRI serves as a valuable tool to assess collision urgency in different scenarios and contribute to determining priorities during multi-ship collision avoidance situations. ...
June 2022
Journal of Marine Science and Engineering