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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 31 for “"Ship Motion"”.
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Identification of nonlinear ship motion using perturbation techniques
… identification scheme for the dynamic model of a ship at sea. We determine the form of the governing differential equations for a ship which is free to pitch and roll, but constrained in all other degrees of freedom, using a perturbation-energy technique. This technique approximates energy …
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Changing mass applications in an advanced time domain ship motion program
Thesis (Nav.E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2000.
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Simplified Analysis of IMU Sensor Corruptions on Existing Pendulation Control System For Ship-Mounted Crane
Ship-mounted boom cranes play an important role in the ship-to-ship offshore cargo transport process. In recent years, there has been significant need to increase stability of the payload during the cargo transport process for both safety and efficiency reasons. However, the stability of the …
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Development of a Landing Period Indicator and the Use of Signal Prediction to Improve Landing Methodologies of Autonomous Unmanned Aerial Vehicles on Maritime Vessels
… detection and ranging system to aerially detect ship motion. The observed ship motion is forecasted using signal prediction which identifies and notifies the UAV of potential landing opportunities. The Signal Prediction Algorithm (SPA) is also used for Active Heave Compensation (AHC) to …
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Cargo Pendulation Reduction on Ship-Mounted Cranes
… necessary to transfer cargo from a large ship to a smaller ship at sea. Specially designed craneships are used for this task, however the wave-induced motions of the ship can cause large pendulations of cargo being hoisted by a ship-mounted crane. This makes cargo transfer in rough seas …
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Investigating the Use of Inductive Transfer Learning and RNN to Quantify Extreme Event Statistics of Ship Motions
Ship motion software has been a critical tool for designers to study the extreme responses of ships in irregular waves. These studies and simulations often take thousands of hours to predict and analyze the ship’s motion. Simulation results are often imperative to ensure the development of accurate …
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Time domain mathematical model for six-degree-of-freedom motion in a wave
To assess the behaviour of a ship in a seaway, this thesis presents the development of an integrated mathematical model describing a six-degree-of-freedom motion of a ship in a wave. This integrated mathematical model is developed with its fundamental base on both traditional seakeeping and …
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Computer simulation of a large-scale non-linear feedback control system
… system that filters out the effects of surface ship motion on a weapon's response to commands from the ship's fire control center. The network includes a number of non-standard elements that prevent mathematical prediction of its closed-loop response; therefore, a computer model was required to …
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Simulation of Multi-Layer-Liquid Sloshing Effects on Vessel Motions by Using Moving Particle Simulation
The coupling and interactions between ship motions and inner-liquid tank sloshing have been investigated by a coupled program between ship motion and sloshing analysis programs. For the sloshing program, Moving Particle Simulation (MPS), which is based on the Lagrangian approach, is used. This …
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Identification of Finite-Degree-of-Freedom Models for Ship Motions
Accurate ship-motion prediction is important because it is directly related to the design, control, and economic operation of ships. Many methods are available for studying and predicting ship motions, including time-domain, strip-theory, and system-identification-based predictions. Time-domain and …
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Control Design and Model Validation for Applications in Nonlinear Vessel Dynamics
… validation tools. In the study of some ship motion behavior, chaos exists, which results in chaotic time series simulations. This presents novel challenges for validation; direct comparison may not be the most apt approach. For these applications, there is a need to develop appropriate …
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Análise de esforços e cálculo de fadiga no transporte de plataformas offshore
… "in place" phase. The structure is subjected to motions obtained in the analysis of similar system under environmental actions in irregular sea states. The ship motion analysis was carried out by using the strip method technique. The steady state of the structure is obtained by means of a linear …
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Parameter Identification of Nonlinear Systems Using Perturbation Methods and Higher-Order Statistics
… of the procedure, numerical simulations of ship motion under parametric excitation are used to determine nonlinear parameters govening the relation between pitch, heave, and roll motions. The results show a high level of agreement between the numerical simulation and the mathematical model …
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Modelo numérico de efeitos hidrodinâmicos em escoamentos internos e externos
… model for external and internal flows to a ship under regular waves. The numerical model consists of the coupling of two methods with different nature, which were evaluated independently in a first stage. The first one is the time domain method based on the panel method and potential theory …
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Current velocity profiling from an autonomous underwater vehicle with the application of Kalman filtering
… intelligent control, independence from ship motion and weather constraint, and shallow water operation. First, an acausal postprocessing scheme is presented for estimating the AUV's own velocity and removing it from the relative velocity measurement to obtain the true current velocity. …
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Dynamics of a vertically tethered marine platform
Rapid and high resolution motion and tension measurements were made of a typical vertically tethered system, a caged deep-sea ROV, while it operated at sea. The system is essentially one-dimensional because only the vertical motions of the underwater platform and the ship were coherent, while …
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Automatic Landing of a Rotary-Wing UAV in Rough Seas
… The ability of a RUAV to operate from a ship in the presence of adverse winds and deck motion could greatly extend its applications in both military and civilian roles. This requires the design of a flight control system to achieve safe and reliable automatic landings. Although …
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A Physics-Informed, Data-Driven Framework for Spatially Resolved Motion Sickness Prediction on The SA Agulhas II
… inputs, such as wave spectra, into predictable ship dynamics, necessary for ship design and operational planning. However, a notable gap persists in fully integrating these predicted motions with their direct implications for human occupants, particularly motion sickness. To bridge this divide, …
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Quantification of extreme event statistics in ship design
… models, we are able to capture rare events in ship motion and loading conditions for a modest computational cost. Improvements to the wave groups methodology ensured the slope and amplitude of the incident waves reflected the waves encountered in a given wave spectrum. The remaining discussion …
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Virtual Reality Simulation of Ships and Ship-Mounted Cranes
We present a virtual simulation of ships and ship-mounted cranes. The simulation is carried out in a Cave Automated Virtual Environment (CAVE). This simulation serves as a platform to study the dynamics of ships and ship-mounted cranes under dynamic sea environments and as a training platform for …
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