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Articles 481 - 510 of 1299
Full-Text Articles in Engineering
Real-Time Method For Calculating Retardation Functions, Li-Hao Yuan, Yue-Sheng Ma, Ying-Fei Zan, Zhao-Hui Wu
Real-Time Method For Calculating Retardation Functions, Li-Hao Yuan, Yue-Sheng Ma, Ying-Fei Zan, Zhao-Hui Wu
Journal of Marine Science and Technology–Taiwan
To meet the demand for real-time calculation of time-domain motion equations, a state-space model was established to replace the convolution integral method to improve computational efficiency. On the basis of the HYSY201 vessel, the impulse response curve fitting method and the realization theory method based on the time-domain identification theory were compared to establish the state-space model. The results of roll decay simulation conducted using the state-space model and the convolution integral method were verified against decay test results. The simulation results for retardation function, radiation forces, and motion time histories calculated using the state-space model and the convolution integral …
Survey Of Trajectory Tracking Control Of Autonomous Underwater Vehicles, Wen-Yang Gan, Da-Qi Zhu, Wei-Li Xu, Bing Sun
Survey Of Trajectory Tracking Control Of Autonomous Underwater Vehicles, Wen-Yang Gan, Da-Qi Zhu, Wei-Li Xu, Bing Sun
Journal of Marine Science and Technology–Taiwan
Autonomous underwater vehicles (AUVs) are powerful instruments that enable the exploration of the ocean. In recent years, AUVs have been developed considerably. Trajectory tracking control, which has been a major research focus for many decades due to its variety of applications, is one of the key advancements in the AUV technology. This paper presents six trajectory tracking control methods: PID (proportion integration differentiation) control, fuzzy control, adaptive control, sliding mode control, backstepping control, and neural network control. A few novel methods for trajectory tracking control are also introduced. First, the concept of trajectory tracking control for an AUV and the …
Modeling Of Dynamic Behavior For Port Structures Using The Performance-Based Seismic Design, Cheng-Yu Ku, Jing-Jong Jang, Jui-Ying Lai, Ming-Jr Hsieh
Modeling Of Dynamic Behavior For Port Structures Using The Performance-Based Seismic Design, Cheng-Yu Ku, Jing-Jong Jang, Jui-Ying Lai, Ming-Jr Hsieh
Journal of Marine Science and Technology–Taiwan
The paper presents a pioneer study on numerical modeling of dynamic behavior for port structures using the performancebased seismic design in Taiwan. Since Taiwan is located in earthquake prone area, there is significant interest in improving prediction of the behavior of port structures subjected to seismic loading. The investigation of port structures using three different analysis methods including the simplified analysis, the simplified dynamic analysis, and the dynamic analysis were adopted for evaluating the performance of the cellular quay wall and sheet pile quay wall. In addition, the effective stress analysis with the consideration of the pore pressure generation and …
Cost Of Salvage?€“ A Comparative Form Approach, Chung-Sheng Chiu, Chung-Ping Liu, Ki-Yin Chang, Wen-Jui Tseng, Yung-Wei Chen
Cost Of Salvage?€“ A Comparative Form Approach, Chung-Sheng Chiu, Chung-Ping Liu, Ki-Yin Chang, Wen-Jui Tseng, Yung-Wei Chen
Journal of Marine Science and Technology–Taiwan
The most important principle of salvage is the "No Cure-No Pay" basis, if there is no recovery, there is no payment, whatever the expense of the operation. However, this principle has changed in recent years to reflect the public interest in prevention of damage to the environment (Mudric, 2010). The salvor can now contract in such a way that he is shielded from loss when responding to high risk or low value casualties (so called as "No Cure-Some pay"). Salvage is a high-profit business and high-risk as well in the world. The case of the Costa Concordia - by no …
A Numerical Model For Pipeline Abandonment In Deep Water, Duanfeng Han, Kuo Huang, Yingfei Zan, Zhaohui Wu
A Numerical Model For Pipeline Abandonment In Deep Water, Duanfeng Han, Kuo Huang, Yingfei Zan, Zhaohui Wu
Journal of Marine Science and Technology–Taiwan
In offshore oil and gas engineering, pipeline abandonment is unavoidable and its mechanical analysis is necessary and important. For this problem, a numerical model is developed in this study to evaluate pipeline abandonment for the J-laying method. The whole system considered in this model is divided into two parts: the A&R cable and the pipeline in the water. A catenary model was proposed for the former, and the latter is solved by a numerical iterative method. In addition to the boundary conditions at the two end points, a special set of boundary conditions is required at the junction that connects …
Experimental Study Of Dynamic Stability Of Underwater Vehicle-Manipulator System Using Zero Moment Point, Jin-Il Kang, Hyeung-Sik Choi, Mai The Vu, Nguyen Ngoc Duc, Dae-Hyeong Ji, Joon-Young Kim
Experimental Study Of Dynamic Stability Of Underwater Vehicle-Manipulator System Using Zero Moment Point, Jin-Il Kang, Hyeung-Sik Choi, Mai The Vu, Nguyen Ngoc Duc, Dae-Hyeong Ji, Joon-Young Kim
Journal of Marine Science and Technology–Taiwan
For manipulative underwater operations, an underwater vehiclemanipulator system (UVMS) has more degrees of freedom than those required to conduct a given mission. To follow the desired end-effector position and velocity accurately, UVMS should be able to generate trajectories of manipulators and the underwater vehicle can maintain dynamic stability of the entire system. In this paper, redundancy resolution is performed to find a solution satisfying the given task among many joint-space solutions. Also, to improve the dynamic stability of the UVMS, zero moment point (ZMP) is adopted such that it requires some constraints. For application of UVMS, a joint limitation is …
A Time-Domain Numerical Tool For A Wave Energy Attenuator With The Sph Method, Da-Wei Chen, Shuichi Nagata, Shiaw-Yih Tzang, Yasutaka Imai, Chih-Min Hsieh, Jiahn-Horng Chen
A Time-Domain Numerical Tool For A Wave Energy Attenuator With The Sph Method, Da-Wei Chen, Shuichi Nagata, Shiaw-Yih Tzang, Yasutaka Imai, Chih-Min Hsieh, Jiahn-Horng Chen
Journal of Marine Science and Technology–Taiwan
The wave energy attenuator is a floating device which operates perpendicular to the wave fronts and captures wave energy from the relative motions of two hinged floaters as waves passing by them. For establishing the time-domain numerical tools to evaluate the performance of a wave energy attenuator, a Smoothed Particle Hydrodynamic (SPH) model with mesh-free method was adopted to simulate the hydrodynamic behaviors of each floating object. Three different wave heights of 6 cm, 7 cm, and 10.4 cm of the same period of 1.22 s were commonly derived from typical potential oceanic zones offshore Taiwan and Japan. Comparisons of …
Dynamic Response Analysis Of Micro-Grid With Ocean Thermal Energy Conversion, Chia-Yu Hsu, Ming-Wang Chen, Pei-Hwa Huang
Dynamic Response Analysis Of Micro-Grid With Ocean Thermal Energy Conversion, Chia-Yu Hsu, Ming-Wang Chen, Pei-Hwa Huang
Journal of Marine Science and Technology–Taiwan
The main purpose of this paper is to analyze the dynamic responses of micro-grid with Ocean Thermal Energy Conversion (OTEC) system. The power sources of the studied micro-grid system include an OTEC generator and a wind generator. Three different types of OTEC generation systems, i.e., open-cycle, closed-cycle, and hybrid-cycle, are considered, under the conditions with the same temperature of sea water and output of generator. When the system operates in an islanding or gridconnected mode, the responses subject to load variation are quite different. As the system operates in the grid-connected mode, the voltage and frequency are less affected by …
Cyclic Shear Behavior Characteristics Of Marine Silty Sand, Su Won Son, Min Jae Ko, Jin Man Kim
Cyclic Shear Behavior Characteristics Of Marine Silty Sand, Su Won Son, Min Jae Ko, Jin Man Kim
Journal of Marine Science and Technology–Taiwan
Owing to the high demand for energy supply, the use of offshore wind turbines as a renewable and environment-friendly energy source has been remarkably increased. After installation in the ocean, the offshore structure foundations and soil that support them are subjected to cyclic loading from wind and waves. In this study, laboratory experiments were conducted to evaluate the shear behavior characteristics of the marine soil subjected to cyclic loading. Utilizing a cyclic direct simple shear (CDSS) test apparatus, the undrained shear failure behavior of marine silty sand was investigated. The results show that the cyclic behavior and permanent shear strain …
Research On Integration And Sharing Solutions For Big Structured Data For The Marine Environment, Wei Wang, Wenfang Cheng, Jing Chen, Ya-Nan Yu, Jianxun Zhang
Research On Integration And Sharing Solutions For Big Structured Data For The Marine Environment, Wei Wang, Wenfang Cheng, Jing Chen, Ya-Nan Yu, Jianxun Zhang
Journal of Marine Science and Technology–Taiwan
The data-intensive science, a new paradigm in scientific discovery, demands an urgent solution to integrate and share big marine environment data. Through the modeling of marine environmental features (such as Temperature, Salinity, Density et al.), a novel solution is presented in this paper. This solution employs Hadoop and Hbase, based on the Bigtable algorithm first proposed by Google Inc. By using hierarchical technology, scalability of the data integration framework is realized. Additionally, an efficient execution of various queries is realized by using the customized auxiliary index algorithm. In the experimental cluster environment constructed from four ordinary personal computers, experiments involving …
A Simplified Analytical Method For Estimating Flow-Induced Vibration Responses Of Hydraulic Structures Caused By Flow Fluctuation, Ya-Chao Wu, Lu Lu, Qin-Man Fan, Yun Dong, Chun-Yuan Zuo
A Simplified Analytical Method For Estimating Flow-Induced Vibration Responses Of Hydraulic Structures Caused By Flow Fluctuation, Ya-Chao Wu, Lu Lu, Qin-Man Fan, Yun Dong, Chun-Yuan Zuo
Journal of Marine Science and Technology–Taiwan
In many hydraulic engineering investigations of flow-induced vibration responses, a model test is necessary but yet expensive. In this article, an equilibrium equation between the operation of fluctuating pressure and the work done by damping is established to provide a simplified analytical method for estimating the flow-induced vibration responses of hydraulic structures caused by water flow fluctuations. This approach is based on the Westergaard solution. The flow-induced vibration of water flowing around a dividing wall, the flood discharge vibration of the Liuxihe arch dam, and the flow-induced vibration of the Ertan hyperbolic arch dam are presented to explain the detailed …
Oblique Wave Scattering By A Submerged Porous Breakwater With A Partially Reflecting Sidewall, Yang Zhao, Hua-Jun Li, Yong Liu
Oblique Wave Scattering By A Submerged Porous Breakwater With A Partially Reflecting Sidewall, Yang Zhao, Hua-Jun Li, Yong Liu
Journal of Marine Science and Technology–Taiwan
This study develops an analytical solution for oblique wave scattering by a submerged porous breakwater with a leeside partially reflecting vertical wall. The matched eigenfunction expansion method is used to develop the analytical solution. The whole fluid domain is divided into three regions according to the geometries of the structures. The series solution of the velocity potential in each region is obtained by the separation of the variables, and the unknown expansion coefficients are determined using the pressure and velocity continuous conditions on interfaces of different regions. The newly developed analytical solution is confirmed by an independently developed multi-domain boundary …
Non-Parametric Identification Of Nonlinear Damping And Restoring Forces For Ship Free Roll Decay In Numerical Tank, Yin Jiang, Ren-Chuan Zhu, Guo-Ping Miao, Ju Fan, Chao Ma
Non-Parametric Identification Of Nonlinear Damping And Restoring Forces For Ship Free Roll Decay In Numerical Tank, Yin Jiang, Ren-Chuan Zhu, Guo-Ping Miao, Ju Fan, Chao Ma
Journal of Marine Science and Technology–Taiwan
Numerical simulations of free roll decay are carried out for the DTMB 5512 based on computational fluid dynamics (CFD) theory and adoption of overset mesh technology. The numerical time history of the ship roll shows good quantitative agreement with the experimental time history in the case of Fr = 0.138 with an angle of list of θa0 = 10°. The natural period is well estimated, there is less than 2% error. According to the time history of the roll angle and the corresponding angular velocity, the nonlinear ship roll damping and restoring force of the hull are identified by solving …
Feasibility Assessment Of Substituting Stainless Steel With Aluminum Alloy For Hydraulic Gate, Kuo-Ho Chen, Tien-Kuen Huang
Feasibility Assessment Of Substituting Stainless Steel With Aluminum Alloy For Hydraulic Gate, Kuo-Ho Chen, Tien-Kuen Huang
Journal of Marine Science and Technology–Taiwan
In this paper, the feasibility of using aluminum alloy 5083 as a replacement for currently used stainless steel SUS 304L on hydraulic gate is evaluated. Relevant properties of these two materials are compared for use in hydraulic gates. Forty common types of hydraulic gates were analyzed through the finite element program PLAXIS 3D Foundation. It shows the weight for most types of hydraulic gates with aluminum alloy 5083 is in the range of 37.6-45.9% of that of stainless steel SUS 304L. At the same time, the cost of gate manufacturing is reduced 39.6-50.5% and cost of maintanence/operation can be reduced …
Improved Analysis Of Bolted Shear Connection Under Eccentric Loads, Dung-Myau Lue, Cheng-Yen Liao, Chien-Chien Chang, Wei-Ting Hsu
Improved Analysis Of Bolted Shear Connection Under Eccentric Loads, Dung-Myau Lue, Cheng-Yen Liao, Chien-Chien Chang, Wei-Ting Hsu
Journal of Marine Science and Technology–Taiwan
Almost all bolted connections are eccentrically loaded. The American Institute of Steel Construction (AISC) permits the use of elastic and instantaneous center of rotation (IC) methods to analyze eccentric bolted connections. The elastic method normally yields relatively conservative designs and the IC method, which provides more realistic analyses, is rather complex and tedious. The current AISC manual provides tables for determining coefficient C, which is used to obtain the design strength of bolt group patterns. However, the tables provide values for only six angles of inclination (θ = 0°, 15°, 30°, 45°, 60°, and 75°). For other angles, a direct …
Comparison Of Fatty Acid Compositions And Fuel Characteristics Of Biodiesels Made From Isochrysis Galbana Lipids And From Used Cooking Oil, Cherng-Yuan Lin, Bo-Yu Lin
Comparison Of Fatty Acid Compositions And Fuel Characteristics Of Biodiesels Made From Isochrysis Galbana Lipids And From Used Cooking Oil, Cherng-Yuan Lin, Bo-Yu Lin
Journal of Marine Science and Technology–Taiwan
The fatty acid compositions and typical fuel characteristics of the biodiesels produced from Isochrysis galbana lipids and used cooking oil were analyzed and compared in this study. The experimental results showed that the major fatty acid compositions of the biodiesel made from the extracted Isochrysis galbana lipids were significantly different from those of the biodiesel made from used cooking oil. The biodiesel made from the microalgae lipids primarily comprised 35.34 wt. % myristic acid (C14:0) whereas the major compound of the used cooking-oil biodiesel was 47.51 wt. % oleic acid (C18:1). Docosahexaenoic acid (DHA) at 4.67 wt. % was only …
Mixed H2/Passivity Performances Control Of Discrete-Time Linear Stochastic Systems, Cheung-Chieh Ku, Rui-Wen Chen
Mixed H2/Passivity Performances Control Of Discrete-Time Linear Stochastic Systems, Cheung-Chieh Ku, Rui-Wen Chen
Journal of Marine Science and Technology–Taiwan
A mixed performance control problem of discrete-time linear stochastic systems is discussed and investigated subject to H2 and passivity performances in this paper. Based on Itô modeling approach, stochastic systems can be represented as deterministic difference equation with multiplicative noise term. For the stochastic systems, H2 minimization problem and passivity constraint are simultaneously considered to achieve minimum output energy and attenuation performance. Applying Lyapunov theory, some sufficient conditions are derived into extended Linear Matrix Inequality (LMI) form to apply convex optimization algorithm. Moreover, a mixed H2/Passivity performance controller can be designed such that asymptotical stability and required performances of closed-loop …
An Improved Algorithm Of Trubulence Signal Denoising Based On Lms Adaptive Filtering, Xue Chen, Da-Lei Song, Xin Luan, Hua Yang, Xiu-Yan Liu
An Improved Algorithm Of Trubulence Signal Denoising Based On Lms Adaptive Filtering, Xue Chen, Da-Lei Song, Xin Luan, Hua Yang, Xiu-Yan Liu
Journal of Marine Science and Technology–Taiwan
Restricted by observation instruments and methods, the measured turbulence signals in the open ocean are inevitably affected by noise. To maximum eliminate the noise caused by the vibration of the instruments and improve the accuracy of the measured turbulence signals, an improved turbulence signal denoising algorithm based on least mean square (LMS) adaptive filter is proposed in this paper. The key point of the improved algorithm is to obtain the optimal weight value by the adaptive adjustment and remove the vibration noise from the measured shear signals in frequency domain. Through taking the Nasmyth theoretical spectrum as the desired signal …
Intelligent Computation And Dsp-Based Landing Control, Jih-Gau Juang, Hou-Kai Chiou, Chia-Ling Lee
Intelligent Computation And Dsp-Based Landing Control, Jih-Gau Juang, Hou-Kai Chiou, Chia-Ling Lee
Journal of Marine Science and Technology–Taiwan
This paper presents several digital signal processor (DSP) based intelligent controllers for aircraft automatic landing systems (ALSs). Proportional-Integral-Derivative (PID) control law is adopted in the intelligent controller design. A fuzzy cerebellar model articulation controller (CMAC) is utilized to compensate for the PID control signal. Control gains are selected by evolutionary computation. The controllers' tracking performance of preset landing paths and capability to adaptively respond to different disturbances are demonstrated through hardware simulations. Different evolution methods, namely Adewuya crossover, arithmetical crossover, average crossover, convex crossover and blend crossover are utilized to analyze the controllers’ performances in terms of optimal parameter search. …
Evaluation Of Different Trading Routes On Fatigue Damage For A 216k M3 Lng Carrier, Ozgur Ozguc
Evaluation Of Different Trading Routes On Fatigue Damage For A 216k M3 Lng Carrier, Ozgur Ozguc
Journal of Marine Science and Technology–Taiwan
This paper aims to address long term loads and fatigue damage accumulation for different trading routes relative to North Atlantic operations based on IACS scatter diagram for a 216,000 m3 LNG carrier. The evaluation is based on direct wave load analysis using WASIM and scatter diagrams created in accordance with DNV Code 30.5 for the following trades: 1. North Atlantic 2. World Wide 3. Qatar - Boston 4. Qatar - UK 5. Murmansk - Boston 6. Murmansk - Rotterdam 7. St. Petersburg - Canada 8. Sakhalin - Mexico port close to California USA 9. Sakhalin - Shanghai, China It is …
The Underwater Towed System Behavior During Ship Turning Maneuvers, Zhi-Jiang Yuan, Liang-An Jin, Wei Chi, Xiao-Gang Jiang, Zhi-Lin Zheng
The Underwater Towed System Behavior During Ship Turning Maneuvers, Zhi-Jiang Yuan, Liang-An Jin, Wei Chi, Xiao-Gang Jiang, Zhi-Lin Zheng
Journal of Marine Science and Technology–Taiwan
The depth and attitude of underwater towed system show complex behavior during the towing ship turning maneuvers. However, it remains unclear how the two indexes change when the coupling relationship between the cable and the towed vehicle is considered. Here, to solve this issue, and we develop a new numerical method that can be used to predict the behavior of towed system during towing ship turning maneuvers. Specially, a finite difference method and six-degree-of-freedom equations are used to describe the motion of towed cable and towed vehicle respectively. Based on the center finite difference method, the partial differential equations and …
A Numerical Identification Of Excitation Force And Nonlinear Restoring Characteristics Of Ship Roll Motion, Jinsoo Park, Hong Gun Sung, Fayyaz Ahmad, Soo Hyun So, Stavros Syngellakis, Kwang Hyo Jung, Taek Soo Jang
A Numerical Identification Of Excitation Force And Nonlinear Restoring Characteristics Of Ship Roll Motion, Jinsoo Park, Hong Gun Sung, Fayyaz Ahmad, Soo Hyun So, Stavros Syngellakis, Kwang Hyo Jung, Taek Soo Jang
Journal of Marine Science and Technology–Taiwan
The present work identifies the nonlinear restoring characteristics and excitation force of ship roll motion in regular beam waves. The steady-state roll response data measured from a numerical simulation is utilized for the experiments of the applied method. Using the approach proposed by Jang (2014), the J-function and its one of zero-crossing times play a crucial role in the identification. The J-function is defined to be the sum of inertia force and nonlinear damping. For the zero-crossing time to be measured, system responses of angular displacement, velocity and acceleration need to be known and so does the numerical interpolation. Numerical …
A Modified Sumner Method For Obtaining The Astronomical Vessel Position, Tien-Pen Hsu, Guo-Yu Weng, Chih-Li Chen
A Modified Sumner Method For Obtaining The Astronomical Vessel Position, Tien-Pen Hsu, Guo-Yu Weng, Chih-Li Chen
Journal of Marine Science and Technology–Taiwan
An adaptive boundaries technique (ABT) yielded by the geometrical properties of celestial triangles is proposed to deal with problems resulting from ex-meridian or meridian sights when the Sumner method is used. Due to the trial-and-error characteristic of the Sumner method, an iteration method is introduced to improve numerical accuracy. Combining the ABT and the iteration method into the Sumner method, this modified Sumner method (MSM) is developed so that it successfully determines the astronomical vessel position (AVP). Especially when the non-simultaneous sights condition is encountered, based on the running fix concept, middle-latitude sailing is adopted to translate Sumner points to …
Zinc-Rich Lithium Silicate Coatings For Corrosion Prevention In Steels, Jiang-Jhy Chang, Wei-Chung Yeih, Kuo-Lien Chen, Maochieh Chi
Zinc-Rich Lithium Silicate Coatings For Corrosion Prevention In Steels, Jiang-Jhy Chang, Wei-Chung Yeih, Kuo-Lien Chen, Maochieh Chi
Journal of Marine Science and Technology–Taiwan
In this study, we investigated the properties of zinc-rich lithium silicate coatings using various moduli of lithium silicate and zinc powder ratios, which are defined as the mass ratios of zinc powder over lithium silicate. Coating properties examined included film-forming ability, workability, mechanical behavior, resistance to highly alkali or acid solutions, and weather resistance (ultraviolet exposure test). The results showed that the zinc powder ratio significantly influenced workability and filmforming ability. When the zinc powder ratio of the coating was low, the coating delaminated and cracked. When the zinc powder ratio was high, the workability of the coating was found …
Hydrodynamic Prediction Of The Ducted Propeller By Cfd Solver, Sohrab Majdfar, Hassan Ghassemi, Hamid Forouzan, Arash Ashrafi
Hydrodynamic Prediction Of The Ducted Propeller By Cfd Solver, Sohrab Majdfar, Hassan Ghassemi, Hamid Forouzan, Arash Ashrafi
Journal of Marine Science and Technology–Taiwan
Ducted propellers are usually used in many kinds of vessels, i.e., fishing vessels, trawlers, and submarines which have provided high efficiency in propulsion system. In this article, the effects of the length and angle of 19A type duct on the hydrodynamic performance were investigated. First, the ducted propeller (19A type duct) was selected for the study and modeling of this duct was later developed. Then, ducted propeller performance was analyzed by a RANS turbulence model of SST-K-ω and validated with the experimental results which indicated an acceptable accuracy. Finally, the effects of the implemented changes were analyzed considering the alternation …
Robust Trajectory Tracking Control Of Underactuated Underwater Vehicle Subject To Uncertainties, Yuan Chen, Jing Li, Kanglin Wang, Shurong Ning
Robust Trajectory Tracking Control Of Underactuated Underwater Vehicle Subject To Uncertainties, Yuan Chen, Jing Li, Kanglin Wang, Shurong Ning
Journal of Marine Science and Technology–Taiwan
A composite robust control scheme is proposed by combining a sliding mode controller with an adaptive fuzzy control algorithm to control a 3-DOF underactuated underwater vehicle with model parameter perturbations and environmental disturbances based on the backstepping control method and the Lyapunov stability theory. The adaptive fuzzy control algorithm is employed to compensate for model parameter perturbations and the sliding mode controller is adopted to eliminate the effects of environmental disturbances and approximation errors. A horizontal dynamic model and tracking error equations are established to describe the trajectory tracking control for the underactuated underwater vehicle. The relation between sliding mode …
Experimental Study On Hydrodynamic Performance Of A New Type Of Deep Draft Multi-Column Fdpso, Jia-Yang Gu, Yu-Lin Xie, Pei Zhang, Yu Chen, Xiang-Hong Huang, Yan-Wu Tao
Experimental Study On Hydrodynamic Performance Of A New Type Of Deep Draft Multi-Column Fdpso, Jia-Yang Gu, Yu-Lin Xie, Pei Zhang, Yu Chen, Xiang-Hong Huang, Yan-Wu Tao
Journal of Marine Science and Technology–Taiwan
This paper presents an experimental study on the hydrodynamic performance of a new type of deep draft multi-column FDPSO. The operating depth of this new type FDPSO is 1500 m. The main dimension, the special variable cross-section column and the cabin arrangement of the octagonal pontoon are introduced. As taking into account the depth limit of the water basin, the 300 m water-depth equivalent truncated mooring system is adopted. The platform’s natural period and dimensionless damping coefficient were measured out by the free decay experiment. The FDPSO's motion responses in operation condition and self-survival condition are studied. At the same …
A Modification Of Ensemble Empirical Mode Decomposition Method, Chu-Kuan Lin, Wei-Po Huang, Grzegorz Różyński, Jaw-Guei Lin
A Modification Of Ensemble Empirical Mode Decomposition Method, Chu-Kuan Lin, Wei-Po Huang, Grzegorz Różyński, Jaw-Guei Lin
Journal of Marine Science and Technology–Taiwan
An adjustment about the added white noise in Ensemble Empirical Mode Decomposition (EEMD) of Wu and Huang (2008) was presented in this paper. The EEMD establishes an ensemble by adding time series of finite but not infinitesimal amplitude white noise into a time series of the signal to solve the mode-mixing problem occurred in the conventional EMD method. The adding ensembles of noise are supposed to be exhausted from all possible solutions from the sifting process. However, in the Matlab script of the theory, it was found that the added noise could not be averaged out through the whole process. …
Intelligent Detection Of Serial Arc Fault On Low Voltage Power Lines, Chi-Jui Wu, Yu-Wei Liu, Chen-Shung Hung
Intelligent Detection Of Serial Arc Fault On Low Voltage Power Lines, Chi-Jui Wu, Yu-Wei Liu, Chen-Shung Hung
Journal of Marine Science and Technology–Taiwan
Some reports reveal that a number of home fires are caused by electric arc faults on low voltage electric power lines. The arc fault circuit interrupter (AFCI) is a device to detect arc faults. However, the accurate rate of detection by commercial AFCIs is still imperfect. In this paper, an intelligent method is intended to improve the detection ability. A wavelet based stationary non-stationary filter (WTST-NST) is employed to eliminate the impulse components of measurement data. Then, the discrete wavelet transform (DWT) and the multi-resolution are used to obtain the signal energy in the corresponding frequency band. A back propagation …
Application Of Morlet Wavelet In The Diagnosis Of Noise Signal Characteristics Of A Wind Turbine Blade In Abnormal Operation, Chao-Nan Wang, Yao-Chi Tang
Application Of Morlet Wavelet In The Diagnosis Of Noise Signal Characteristics Of A Wind Turbine Blade In Abnormal Operation, Chao-Nan Wang, Yao-Chi Tang
Journal of Marine Science and Technology–Taiwan
This study developed an estimation model for noise signal characteristic diagnosis based on the time-frequency analysis technique. The time-frequency analysis theory uses the relatively mature and extensively used wavelet method as the basis of signal analysis, but wavelet analysis generates wavelet theories different from other mother wavelet methods. This study used the Morlet Transform, which is a type of wavelet transform using a mother wavelet for wavelet analysis of signals. The time axis was integrated according to the result of time-frequency analysis in order to obtain the marginal spectrum value of the frequency domain. Finally, statistical regression analysis was used …