Showing papers in "Ocean Engineering in 2020"

TL;DR: In this article, the authors provide an overview of the current state and future trends of the offshore wind farms worldwide along with the technological challenges, especially the wind farm layout and the main components.

TL;DR: The power take-off systems of the wave energy converters (WEC) based on the different working methods of their power take off systems are reviewed, showing that the mechanical direct drive system is the most popular.

TL;DR: The fluid dynamics of flapping foils are reviewed in this paper, where a wide range of researches are conducted for the two-dimensional flapping foil which has a relatively simple geometry, however, for a three-dimensional foil, the aspect ratio and shape take effects and completely distinct fluid dynamics are revealed compared with the 2D one.

TL;DR: The computed results in this paper are more conformity with statistical data for that the error of predicted failure rate of this study is 4.5%, which can be compared with that of 13% concluded by fault tree analysis.

TL;DR: A deep reinforcement learning (DRL)-based collision avoidance method is proposed for an unmanned surface vehicle (USV) and a grid map representation of the ship encounter situation was suggested to utilize the visual recognition capability of deep neural networks for analyzing the complex and ambiguous situations that are typically encountered.

TL;DR: The simulating waves nearshore-LSTM (SWAN-L STM) model was proposed to make a single-point prediction, and it outperformed the standard SWAN model with an improvement in accuracy of over 65%.

TL;DR: The approach consists of identifying relevant waypoints along a route where significant changes in the ships’ navigational behaviour are observed, such as changes in heading, using trajectory compression and clustering algorithms to provide a vector-based representation of the ship routes consisting of straight legs and connecting turning sections that facilitates route probabilistic characterization and anomaly detection.

TL;DR: A framework for the identification of factors that influence the navigational risk of remotely controlled MASS without crews on board is proposed and may assist the processes of design and operational planning of maritime transportation systems accommodating MASS and its remote-control center, e.g., the shore control center.

TL;DR: In this article, the authors applied a combination of qualitative physical modeling and wavelet analyses of the tsunami as well as numerical modeling to propose a source model, and constrained the tsunami source dimension and initial amplitude in the ranges of 1.5-2.5km and 100-150m, respectively.

TL;DR: In this paper, a meshless generalized finite difference method (GFDM) was proposed for water wave-structure interactions with multiple bottom-seated-cylinder-array structures based on the moving least squares theory and second-order Taylor series expansion.

TL;DR: In this article, a review of the latest progress on the vortex-induced vibration (VIV) in marine risers is presented, including the multi-mode response, VIV response at high Reynolds numbers, flow-induced vibrations between multiple marine RISers, VIG of inclined risers and intermittent VIV in oscillatory flow.

TL;DR: A finite-time extended state observer-based nonsingular fast terminal sliding mode control (NFTSMC) is proposed for the trajectory tracking of autonomous underwater vehicles (AUVs) with various hydrodynamic uncertainties and external disturbances.

TL;DR: From the results of both scenarios for overtaking and following, it illustrates that the timing is significant for strategy selection and should well consider the complex situation and ship behaviours, moreover, the proposed approach can be used for intelligent strategy selection.

TL;DR: A novel dual linear autoencoder approach is suggested to predict the future trajectory of a selected vessel that can serve as a decision support tool to evaluate the future risk of ship collisions.

TL;DR: An event-triggered extended state observer (ESO) is proposed such that unnecessary communications are avoided and sensor-to-observer communication cost are drastically reduced, and the estimation errors are proven to be finite-time ISS.

TL;DR: The paper highlights the need to standardize the reporting of savings through weather routing, to facilitate comparisons between methodologies, which could be achieved through the creation of benchmarking instances.

TL;DR: A new collision avoidance decision-making system designed for autonomous ship that outputs collision avoidance decisions based on the latest information at a certain frequency, which is suitable for real ship application.

TL;DR: The results show that the information, clear order, and safety culture are the three most effective recommendations for maritime accident prevention considering human errors, which presents new insights for accident prevention practice for maritime authorities.

TL;DR: Simulation experiments validate that the proposed hierarchical navigation method, CSPSO algorithm, and collision avoidance rules are effective and justifiable.

TL;DR: A novel fixed-time fault-tolerant control scheme is proposed for trajectory tracking of marine surface vessels (MSVs) and a fixed- time extended state observer (FXESO) is developed to enhance the robustness.

TL;DR: A novel double closed-loop three-dimensional trajectory tracking method based on model predictive control for an autonomous underwater vehicle (AUV) under external disturbances and the stability analysis based on Lyapunov method proves the nominal stability of the controller.

TL;DR: A literature review of wave energy converter and large floating platform integration is presented in this article, where the authors present a review of various integrated systems between wave energy converters and a brief on hydrodynamic analysis of the integrated systems.

TL;DR: This review examines the fluid-structure interactions, between structures and organisms, within cage-based aquaculture, and provides reviews of topics such as mooring and grid systems, drag coefficients of the net panel, hydrodynamic behaviours of cage components, velocity reduction of cage array and volume reduction caused by cage deformation.

TL;DR: The research progress of path planning based on the multi-modality constraint is introduced and the research methods and classical algorithms, especially those applied to the Unmanned Surface Vehicle in every stage are reviewed.

TL;DR: In this article, a hydrodynamic analysis of three different semisubmersible floating offshore wind turbines is carried out including second-order hydrodynamics effects, and the effects of secondorder wave loads on the platform motions and mooring tension are discussed and compared by using different methods including Newman's approximation and the full QTF (Quadratic transfer function) method.

TL;DR: In this article, the authors used a simple barrier to deviate the fluid flow from the reversing bucket of the Savonius turbine to enhance its generated power, and numerical modeling has been performed by applying computational fluid dynamics (CFD).

TL;DR: The nominal output feedback controller proposed in this paper is chatter-free guaranteeing the steady performance and an adaptive update law is introduced that the prior knowledge of disturbance is no need and the finite-time convergence of loop-system is proved strictly.

TL;DR: The adaptive disturbance observer design for the robust trajectory tracking problem for underwater vehicles in presence of unknown external disturbances and parametric uncertainties is proposed and aims to improve the Backstepping and nonlinear PD controllers.

TL;DR: Aiming to precisely estimate completely unknown dynamics together with external disturbances, a distributed tracking controller based wavelet neural network (WNN) is further proposed within the coordinated tracking strategy.

TL;DR: It is shown that the CICA algorithm converges with fewer training times through e-greedy with both decaying e and reward threshold than other three strategies, and it is concluded that theCICA algorithm is superior to the other two algorithms.