bluuebunny/crossref_metadata_2025_split huggingface dataset:
Augmented Adaptive Filter for Real-Time Sea State Estimation Using Vessel Motions Through Deep Learning
Authors: Majidiyan Hamed , Enshaei Hossein , Howe Damon 
Published: September 2023

Abstract
Given the recent rise of autonomous shipping, the knowledge of environmental seaway awareness has become imperative for automated control systems onboard and autonomous units in general. The real-time wave data enables the decision-maker to evaluate dynamic wave loads on the marine structure and efficiently monitor/operate the vessel’s conditions on and off-site. To this end, the wave buoy analogy (WBA) aims to benefit from 6 DOFs ship responses to estimate the induced wave specifications. Although this concept has been extensively scrutinized, the integration of AI and its subsets, machine and deep learning in this field is new. So, the objectives of the current research are twofold; the first is to take advantage of temporal and spectral information for seaway estimation in a deep learning model. The second is to propose a solution addressing two significant issues of WBA: the time lag between the exciting wave and corresponding estimation and stabilizing outputs. The study uses a setup to integrate an ARIMA-EMD predictive filter to adjust sampling window size adaptively on the upcoming data based on the anticipated fluctuations. A major advantage is that filter helps to reduce time lag while improving estimation stability. The response data is synthesized according to a tested semi-submersible platform at Shanghai Jiao Tong University (SJTU) research institute, where the time series is transformed into the pictorial presentation through several processing stages to feed a deep learning network. For training, the concept of transfer learning has been utilized by a pre-trained network, AlexNet. The result is promising and provides a foundation for attaining real-time wave updates in operational scenarios.
A New Approach for Natural Gas and Hydrogen Blast Loading Analysis: A Fixed Mass Perspective
Authors: Lee Hyun Ho , Seo Jung Kwan 
Published: September 2023

Abstract
A fixed mass perspective signifies a concept of which the mass of flammable or combustible gas is fixed but the volume and concentration could be different depending on leak conditions such as location and size of leak hole, ventilation conditions, etc. This phenomenon could make the explosion level different, even if the total amount of combustible/flammable material is the same. Nevertheless, most of related studies on the gas explosion have been conducted in a fixed volume perspective which is a concept with fixed volume and variable mass of combustible/flammable material. In this study, therefore, the blast loading analysis in the fixed mass perspective on the natural gas which is being used in the maritime transport industries and hydrogen which will be used as eco-friendly energy in the future was performed by CFD simulations. The upper deck, where the fuel storage tank could be located, and compartment, where the engine and pipe could be positioned, were selected as geometrical conditions of explosion simulations because these spaces have the relatively high possibility for leak and explosion accidents in ships.
NeMo: A Multi-Draft Mooring Line Failure Detection System Based on FPSO Predicted Motion
Authors: Sa'ad Amir Muhammed , Cunha Rodrigo Da Silva , Barreira Rodrigo Augusto , Tannuri Eduardo Aoun , Gomi Edson Satoshi , Costa Anna Helena Reali 
Published: September 2023

Abstract
Mooring line breakage of a moored offshore Floating Production Storage and Offloading (FPSO) platform results in an increased load on the remaining lines, worsening their degradation rates. Furthermore, a line break causes the FPSO to change its motions and move away from the desired location. In addition, platform motions differ depending on its draft and environmental conditions, making it difficult to detect mooring line failure. In this paper, we propose a system based on machine learning called Neural Motion Estimator (NeMo) composed of (i) a multilayer perceptron network capable of forecasting the horizontal motions of a FPSO with 18 mooring lines under 14 draft configurations, from ballasted (8 meters) to full load (21 meters), and (ii) a multinomial logistic regression classifier that provides the associated probability of failure for each line group in the mooring system. The results of several tests show that NeMo was able to identify the occurrence of line breakage in all draft configurations with a minimum percentage of false classification.
Assessing Underwater Noise Impact From Marine Projects
Authors: Lenchine Valeri V. 
Published: September 2023

Abstract
A substantial number of marine infrastructural projects result in increased environmental impact on marine fauna during the construction and operational stages of the projects. A significant part of this impact is due to excessive noise. The absence of standard methods of underwater noise assessment and prediction increase the risk of unacceptable change to the marine environment as a result of offshore anthropogenic activities. Generally, the auditory systems of marine species are different from that of humans, however it is typical to attempt to extend the same approaches as used for human settings to marine ecosystems. The justification of such approaches is not provided, however it is well understood from a practicability perspective.
Construction operations such as pile driving and dredging may result in significant noise increase and irreversible impact on marine species. This paper reviews relevant regulatory documents and summarizes considerations that are typically used to setting relevant underwater criteria for construction and operational noise. It also suggests approaches to groups of acoustic criteria that may be used to control and minimize underwater noise impact.
General methods of modelling underwater noise impact are reviewed as a part of planning for marine projects and identifying the need for noise mitigation measurements and preparation of relevant construction and operation plans. These approaches may be used to identify relevant noise criteria and submit environmental effect statements to attain regulatory approvals.
Probabilistic Methods for Estimation of the Extreme Air Temperature Along the Northern Sea Route
Authors: Huang Yuexiang , Chai Wei , Zeng Jiayan 
Published: September 2023

Abstract
In recent years, as a great increment in the demand for energy resources, the Northern Sea Route (NSR) has received increasing attention as a potential shortcut for connecting East Asia and Europe. For ships sailing in the Arctic regions, many hazards could be encountered due to the low air temperature, such as ship icing phenomenon, brittle-fracture of steel structures and freezing of liquids within pipes, etc. Therefore, an accurate estimation of the extreme values for the air temperature could provide valuable information for the selection of steel material as well as for the winterization strategies for the ships sailing along the NSR. In this work, a collection of 40-year (1981–2020) historical air temperature data is obtained from the Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2), which is an atmospheric reanalysis tool developed by NASA and four representative sites along the NSR are selected for the investigation. Subsequently, the traditional block maxima method and the proposed average conditional exceedance rate (ACER) method are applied in order to estimate the extreme air temperatures at the four representative sites. The block maxima method is executed by application of the parametric distribution functions, while the ACER method is based on a sequence of nonparametric distribution. The accuracy, efficiency and robustness of the proposed methods are compared and studied in details.
A Mechanistic Model for Predicting the Formation of the Riser Blockage
Authors: Sun Deping , Liu Haixiao 
Published: September 2023

Abstract
A riser blockage is a possible risk in hydraulic transport for deep-sea mining, which seriously affects transport efficiency and safety. To avoid blockages in pipes, it is crucial to predict the conditions of the blockage formation. The present work aims to develop a theoretical model to predict the appearance of the riser blockage based on mechanism analyses. The theoretical model is set up as follows. Firstly, the friction force between the pipe wall and particles at high concentrations is analyzed. Secondly, the deceleration and acceleration processes of target particles are investigated, considering the particle-particle, turbulence particle and wall-particle interactions. Finally, a dynamic equilibrium is established based on the above analysis. The solution of the equation is less than or equal to zero when the blockage is formed, which implies that the critical condition of the blockage formation in vertical pipes is obtained. The validation work is then performed by comparing the predicted results with experimental data available in the literature. To acquire further knowledge of the formation of the riser blockage, the effects of six parameters of the model are investigated in detail, including the ratio of particle diameter, the fluid velocity, the volume concentration, the pipe diameter, the particle density, and the fluid density.
The Effect of LNG and Diesel Fuel Emissions of Marine Engines on GHG-Reduction Revenue Policies Under Life-Cycle Costing Analysis in Shipping
Authors: Taghavifar Hadi , Prasad Perera Lokukaluage 
Published: September 2023

Abstract
The fuel life cycle involves different phases of extraction/refinery (well to tank: WtT), transport (tank to propeller: TtP), and storage where each of these processes can add a specific amount of emissions to the overall LCCA inventory. During the extraction or operation of machinery on the raw material, the released amount of GHG components is undergoing a change in the generated emissions per functional unit of the consumed fuel. As a result, the machinery efficiency, electricity share, and resources mix during the extraction or refinery would impact the emission factor and subsequent carbon credit plans. Additionally, the transportation characteristics such as the traveled distance, multi-model transportation share, and ship engine fuel efficiency can make difference in the emitted GHGs into the atmosphere. The GHG credit rate and duration under different carbon allowance scenarios in the LNG-powered vessel are considered for the current life-cycle carbon emission cost analysis. For the life-cycle costing, the inflation rate, and the discount rate along with the emission reduction incentives are going to be emphasized in the project’s feasibility indicators and its profitability. The results have shown to what extent the LNG use in marine transportation can favor green shipping and how the legislated carbon incentives encourage the shipping industry for the LNG infrastructure development. The methane slip (evaporation) during the liquefaction of LNG will also be addressed, i.e., during the LNG production phase, and its effect on the emission factor of GHGs to have a better understanding of the challenges and outlook on the LNG production industry and its utilization in shipping.
Design Assessment of Mechanical Wavemakers: A Comprehensive Study Towards Wave-Structure Interaction Applications
Authors: Gamaleldin Muhannad W. , Babanin Alexander V. , Chabchoub Amin 
Published: September 2023

Abstract
The development of novel marine installation concepts and physical wave modeling rely on experimental testing in water wave facilities. A crucial element in such experiments is mechanical wavemakers, which are ubiquitous in many experimental wave tank tests, ranging from shallow to deep water applications such as wave structure interactions, coastal processes, and shore protections. The present study introduces and investigates the influence of geometrical modifications to the classical piston-type mechanical wavemaker on surface wave generation. To achieve this, theoretical models based on the classical linear potential flow hydrodynamics were derived, predicting wave height and power requirements of the proposed wavemaker designs. Moreover, several two and three-dimensional numerical CFD simulations, using the Open-Source Field Operations and Manipulations (OpenFOAM) CFD numerical package, were conducted to validate and assess the proposed theoretical analysis. Finally, experimental tests were performed for a rigidly fixed cylinder subject to monochromatic wave trains to validate the outcomes of the numerical models. Overall, free surface profiles and hydrodynamic-induced forces of the theoretical, numerical, and experimental observations are in very good agreement, indicating the validity of the presented theoretical analysis. The proposed geometrical modifications are relatively straightforward to be applied and extend the versatility of the conventional piston-type wavemakers for different target design wave conditions.
An Experimental Study on the Responses of a Spar-Type Floating Structure Integrated With Aquaculture Systems
Authors: Li Qiao , Dong Shuchuang , Zhou Jinxin , Kitazawa Daisuke 
Published: September 2023

Abstract
The development of floating offshore wind turbines that combine aquaculture has potential economic benefits for both industries. In this study, the heave and pitch dynamic responses of a spar-type floating offshore wind turbine with aquaculture system are investigated by an experimental tank, as a feasibility study. A 1/56 model of a 2MW Spar floating wind turbine is used in the experiment. First, the Spar with an aquaculture feeding system is tested. The feeding system is built above the waterline, which can feed 300 tons of fish for one week. When attaching an additional structure such as a feeding system to the Spar, the structure’s center of gravity is raised, which might affect the stability of the floating structure. By the experiment, there is no noticeable increase in accelerations or motion displacements. Under a particular wave period, the motion of the Spar may be reduced. In addition, the dynamic responses of Spar are investigated when aquaculture cages are set near the Spar model. The target cage is silver salmon farming cage, and it has dimensions of around 25 m in diameter and 9 m in depth. Three model cages are set in front of the Spar facing the wave direction. When comparing the Spar-only testing results, the heave motion is increased but the pitch motion is reduced, because of the interference effects of the cages.
Reliability Analysis of Crack Growth Occurrence for a Secondary Structural Component due to Vibration Excitation
Authors: Kolle Kleivane Siri , Leira Bernt Johan , Steen Sverre 
Published: September 2023

Abstract
Ship hull vibration is a significant contributor to fatigue crack growth and the major sources of vibrations are found to be the main engine vibration excitation, the wave-induced springing and whipping loads, and the action of the propeller. In the midship region, wave-induced loads and the main engine are the major contributors, whereas propeller excitation dominates in the aft region of the ship hull. The vibration problems onboard a ship are very complex and are found at both global and local levels. No general method exists to solve all kinds of vibration problems and hence they need to be evaluated through a cost-by-case approach. The complex and uncertain aspects of hull vibration and fatigue crack growth motivate the need for a reliability-based scheme for assessing the resulting fatigue crack propagation of secondary components and structural details. In the present paper, a probabilistic formulation for the failure probability of the occurrence of crack propagation of a secondary hull component is outlined. A generic cargo hold model is analyzed with engine excitation and wave-induced loading as vibration sources, and a stochastic model for vibration response is obtained based on this. The limit state is presented as the possible occurrence of crack growth. The secondary structural component considered is a pipe stack support, and different initial crack sizes are evaluated. The adequacy of the applied stochastic model for vibration response is evaluated and the accuracy of the estimated failure probability is assessed.
A Basic Investigation of Resonance Characteristics of Water Regions of PW-OWC WECs
Authors: Ikoma Tomoki , Kuwata Airi , Aida Yasuhiro , Masuda Koichi 
Published: September 2023

Abstract
This paper describes resonance characteristics of water regions of OWC (Oscillating Water Column) type WEC models installed with projecting-walls, which are called as PW (Projecting Wall)-OWC devices. We can easily improve PTO performance of an OWC type WEC device by installing projecting walls in front of it. One of the reasons is that such a device can have multi-resonance frequencies. Behaviors of the resonances are complex because we can change the resonance characteristic by varying a damping effect which decides a PTO characteristic. The thing would be that we can easily optimize the characteristic to a sea wave condition. However, the resonance characteristics have not been clarified yet. The paper shows the resonance behaviors of OWC and a water region surrounded by the projecting-walls.
The paper adopted a theoretical approach to predict the resonance characteristic as the primary conversion characteristic. The prediction method is a potential-theory-based model which can directly take into account a damping effect due to PTO in a boundary integral equation of the velocity potentials. As a result, there are two cases. One has two resonance frequencies and another has only one because of damper magnitude as PTO.
Methodology for the Integration of Experimental and Numerical Fluid Dynamics in the Study of a Floating Body Such As a Wind Turbine Subjected to Environmental Loads
Authors: Ducrozet Guillaume , Bouscasse Benjamin , Bonnefoy Félicien , Leroy Vincent 
Published: September 2023

Abstract
The decrease in the computational cost of high-fidelity solvers like Computational Fluid dynamics (CFD) has expanded its use in the design of marine structures. This is true among academics and industrial R&D departments. After a long debate about whether CFD would or not supplant traditional experimental methods, it is widely accepted that the two approaches need to be considered together. The present paper proposes a framework for the integration of both experiments and high-fidelity numerical simulations in the design procedures of offshore wind turbines. It makes use of the nonlinear potential flow software HOS-NWT for wave generation, together with the NREL OpenFast software for wind generation and calculation of aerodynamic loads acting on the structure. For the numerical simulation, the environment (wave field) and aerodynamic loads are fed into the high-fidelity software with adequate couplings in the resolution algorithm. For the experiments, the wavemaker motion is run based on the HOS-NWT result, and the aerodynamic loads are imposed thanks to an actuator controlled by software in the loop system. Different scenarios are considered, from the classical CFD validation with experimental results up to more complex situations where the numerics and the experiments are done in sequence one before the other or vice versa, in order to complement or verify the findings.
Calibration of Dynamic Riser Analysis Using Measured Motion Data
Authors: Bruun Mortensen Karina , Skjerve Håvard 
Published: September 2023

Abstract
For design and analysis of dynamic flexible riser motions, the common practice is to use tailor-made software to create an analysis model based on a large set of assumptions and simplifications regarding hydrodynamic loading and interaction between objects. Normally, most of the applied input values are based on theoretical considerations rather than tests and/or actual measured data, and it can be difficult to assess the overall level of conservatism.
When performing analyses on existing systems e.g., lifetime extensions, it is possible to reduce uncertainties by harvesting actual motion data and calibrate the analysis models to obtain a sound level of conservatism.
In the case described in this paper, dynamic motions of both the Åsgard B semi-submersible platform and the Mid Water Arch (MWA) were measured throughout an entire winter season and used to calibrate the analysis model.
The intention was to develop a method for improving accuracy in modelling of risers over the Åsgard B MWA structure in OrcaFlex.
Spatial and Temporal Evolution Characteristics of Water Quality in the Port Waters - A Case Study of Zhanjiang Port, China
Authors: Guo Jianqun , Jiang Zhonglian , Yu Zhen , Ying Jianglong 
Published: September 2023

Abstract
As an important part of the integrated transport system, ports contribute greatly to the prosperity and development of international shipping. Port construction, loading and unloading operations, incoming and outgoing of vessels, and sewage discharge have certain impact on the port water quality. Meanwhile, the deterioration of port water quality will inevitably affect the marine ecological environment. This paper utilizes the pollutant monitoring data of state-controlled cross-sections in the watershed of Zhanjiang Port area from 2015 to 2022, analyzes the characteristics and correlation of its temporal-spatial variations, and thus overviews its driving factors. The results present a positive correlation between total phosphorus (TP) and NH3N with a correlation coefficient r = 0.752, while a negative correlation is found between TP and dissolved oxygen (DO) with a correlation coefficient r = −0.638. The pH value of the water body has increased steadily while no significant variations have been found in the annual temporal-spatial distribution of DO and TP. The chemical oxygen demand (COD) has shown a fluctuating downward trend while the variation of total nitrogen (TN) appears a “U” shape pattern, reaching a minimum value between June to August each year. In general, the water quality of Zhanjiang Port is poor in summers and good in winters. Human activities and industrial production are the main drivers of water quality pollution. The increasing trend of major water quality parameters indicates that timely countermeasures should be taken to improve water quality of Zhanjiang Port.