Showing papers in "Ocean Engineering in 2019"

TL;DR: Current research trends in the field of AUVs and future research directions are presented and localization and navigation techniques such as inertial navigation to simultaneous localization and mapping being used in current AUVs are discussed in detail.

TL;DR: In this article, the authors reviewed the wakes of different cross-sectional bluff bodies, including circular, square, triangular and rectangular cylinders, and the dependence on the two parameters of Strouhal number, vorticity, circulation, and efflux angle of vortices in the wake of bluff bodies.

TL;DR: A probabilistic trajectory prediction model is proposed that describes the uncertainty in future positions along the ship trajectories by continuous probability distributions and has high prediction accuracy and meets the demands of real-time applications.

TL;DR: This study proposes an efficient method to overcome multiship collision avoidance problems based on the Deep Reinforcement Learning (DRL) algorithm and demonstrates its excellent adaptability to unknown complex environments with various encountered ships.

TL;DR: The proposed GVO-CAS can offer rule-compliant evasive actions with a minimum number of required actions for ships and shows the great potential to use the GVO algorithm in both manned and unmanned ships at sea.

TL;DR: A deep deterministic policy gradient (DDPG) algorithm, which is an actor-critic-based reinforcement learning algorithm, was adapted to capture the USV’s experience during the path-following trials.

TL;DR: A path planning and manipulating approach based on Q-learning, which can drive a cargo ship by itself without requiring any input from human experiences is proposed, which is more effective in self-learning and continuous optimisation, and therefore closer to human manoeuvring.

TL;DR: A comparison of data-driven, multiple regression algorithms for predicting ship main engine FOC considering two different shipboard data acquisition strategies, noon-reports and Automated Data Logging & Monitoring (ADLM) systems is presented.

TL;DR: The rigorous stability analysis based Lyapunov’s method demonstrates the uniform ultimate boundedness of all the tracking errors in the closed-loop system and the effectiveness of the proposed controllers.

TL;DR: Investigation of the state recovery and disturbance estimation of unmanned surface vehicles in the presence of unknown disturbances as well as unmeasured surge, sway, and yaw velocities finds that both velocity and disturbance information can be reconstructed from the position-heading measurement by using global positioning system and gyrocompass.

TL;DR: In this paper, a data driven Digital Twin of the ship is built, leveraging on the large amount of information collected from the on-board sensors, and is used for estimating the speed loss due to marine fouling.

TL;DR: A fuzzy unknown observer-based robust adaptive path following control (FUO-RAPFC) scheme for an underactuated surface vehicle (USV) is proposed, suffering from multiple unknowns including unmodeled dynamics, uncertainties, and disturbances.

TL;DR: The finite-time stability of the systems and the boundedness of containment errors are proved by utilizing graph theory, finite time theory, and Lyapunov technique.

TL;DR: A series of experimental studies on flow-induced vibration (FIV) of two identical elastically mounted circular cylinders in tandem arrangement were carried out in a low turbulence surface water channel as mentioned in this paper.

TL;DR: The novel concept of probabilistic ship domain is proposed, which depicts the ship domain boundary as the vague value rather than the crisp value with a forbidden boundary and a desired boundary, and an effective big AIS data driven approach is developed to determine the probabilism ship domain.

TL;DR: The cost-sharing and multi-function of the breakwater-WEC system can help facilitate the engineering application of the floating breakwaters and WECs.

TL;DR: A fuzzy logic based approach for ship-bridge collision alert by considering ship particulars, bridge parameters and natural environment is proposed and can be implemented in the decision support system for safe navigation or be included in the process of autonomous navigation.

TL;DR: It is concluded that lack of Bridge Resource Management Communication, lack of Communication between Ships, Fatigue and Collision Regulation Violations are the elements with higher occurrence rates and would also have great potential contributing to oil tanker collision once the likelihoods deteriorated.

TL;DR: Results may be used to target the development of condition monitoring systems focusing on critical systems and to find optimal O&M strategies by understanding failure paths of main offshore wind turbine systems resulting in a lower cost of energy and a more optimal risk-return balance.

TL;DR: The results demonstrated that the improved DBSCAN outperforms two existing clustering methods in marine traffic c pattern recognition and exhibits superior performance in terms of both time and quality.

TL;DR: In this paper, the effect of surface roughness on the frictional resistance of a ship was analyzed using a Computational Fluid Dynamics (CFD) based unsteady Reynolds Averaged Navier-Stokes (RANS) simulation model.

TL;DR: The main feature of the proposed control law is that it preserves the advantages of robust control and it does not need the knowledge of the upper bound of the disturbance and it is easy to tune in real applications.

TL;DR: Strict stability analysis indicates that the designed robust formation control law can make AUVs achieve the predefined time-varying formation, while guaranteeing uniform ultimate boundedness of all signals of the AUV formation closed-loop control systems.

TL;DR: Simulation results show that the proposed MPP achieves remarkable path-planning performance in terms of both collision avoidance and adaptability to complex environments.

TL;DR: This paper attempts to provide an insight into a process of accident development related to risks in ship mooring operation which presents a great challenge for ship's crew.

TL;DR: Rigorous theoretical analysis and extensive simulation studies demonstrate that the proposed approach has good tracking accuracy, stability, and anti-jamming ability, thus leading to satisfying trajectory tracking control.

TL;DR: Simulation results substantiate the effectiveness of the proposed path-guided time-varying formation controllers and show the capability of collision avoidance and connectivity preservation against model uncertainties, ocean disturbances and unknown input gains.

TL;DR: The superiority of the proposed swarm control strategy is that the distributed controller and flexible formation enable USVs to follow the target and avoid collisions autonomously.

TL;DR: A practical and robust system identification modelling method for ship manoeuvring motion is presented, to alleviate the impact of noise-induced problems, such as parameter drift or over-fitting, on the model reliability.

TL;DR: The proposed Three-Dimensional Dijkstra’s algorithm can generate global opti- mum ship routing encountering less harsh sea environment, leading to at least 5% reduction of fuel consumption within the analysed cases, and can perform multi-objective voyage optimization with accurate ETA in the planning process.