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Articles 1 - 10 of 10
Full-Text Articles in Engineering
Model Reference Robust Control For Marine Propulsion Systems With Model Uncertainty Caused By Hull Deformation, Zhixiong Li, Xinping Yan, Li Qin, Chengqing Yuan, Zhongxiao Peng
Model Reference Robust Control For Marine Propulsion Systems With Model Uncertainty Caused By Hull Deformation, Zhixiong Li, Xinping Yan, Li Qin, Chengqing Yuan, Zhongxiao Peng
Journal of Marine Science and Technology
A marine propulsion system can be strongly coupled with the hull deformation in a large-scale ship. The interaction of this coupling dynamics increases the nonlinearity and complexity of the control model. Traditional control method based on the empirical PID (proportion-integration-differentiation) parameters has difficulty in dealing with the model uncertainty caused by the hull deflection. However, up to date, limited work has been done to address the model uncertainty problem of the marine propulsion system. It is therefore imperative to develop feasible and effective control systems that take the model uncertainty into account. In this study, a new method based on …
A Piston-Type Porous Wave Energy Converter Theory, Ching-Yun Yueh, Shih-Hsuan Chuang
A Piston-Type Porous Wave Energy Converter Theory, Ching-Yun Yueh, Shih-Hsuan Chuang
Journal of Marine Science and Technology
This study investigates the performance of a piston-type porous wave energy converter (PTPWEC), which consists of a solid wall, a vertical porous plate, a transmission bar, a rigid block constrained by rollers, a spring, and a damper. The PTPWEC is subjected to dynamic external loading by wave actions. To simulate this dynamic system, a mathematical model is used with a single-degree-of-freedom (SDOF) system. Linear wave theory governs the entire fluid domain, which is divided into two regions by the vertical porous plate. Darcy's law is applied to flow through the porous plate. Finally, this investigation employs an eigenfunction expansion to …
Application Of A Support Vector Machine For Liquefaction Assessment, Ching-Yinn Lee, Shuh-Gi Chern
Application Of A Support Vector Machine For Liquefaction Assessment, Ching-Yinn Lee, Shuh-Gi Chern
Journal of Marine Science and Technology
This study presents a support vector machine (SVM)-based approach for predicting earthquake liquefaction. The SVM model database includes five indexes: earthquake magnitude, total overburden pressure, effective overburden pressure, qc values from cone penetration tests (CPT), and peak ground acceleration. The proposed model was trained and tested on a dataset comprising 466 field liquefaction performance records and CPT measurements. A grid search method with k-fold cross-validation was also used to verify the feasibility. Compared with an artificial neural network (ANN)–based method, the SVM-based method has the advantage of increased accuracy and simpler operation. Experimental results show that the proposed SVM approach …
The Experimental Study On Local Scour Around A Circular Pipe Undergoing Vortex-Induced Vibration In Steady Flow, Bing Yang, Tao Yang, Jian-Lin Ma, Jin-Sheng Cui
The Experimental Study On Local Scour Around A Circular Pipe Undergoing Vortex-Induced Vibration In Steady Flow, Bing Yang, Tao Yang, Jian-Lin Ma, Jin-Sheng Cui
Journal of Marine Science and Technology
The local scour around a circular pipe undergoing vortexinduced vibration is investigated experimentally in a water flume. The typical characteristic of local scour is analyzed in detail. The influences of initial gap-to-diameter ratio (e0/D), the mode of pipe vibration and the sand type on the local scour are discussed. Experimental results indicate that there exists strong intensity of scour when the pipe moves close to the surface of the sandy bed. The vibration of the pipe results in the rapid development of sandy bed’s scouring. With the increase of gap-to-diameter ratio the distance between the center of the pipe and …
An Improvement Of Wave Refraction-Diffraction Effect In Swan, Aw-Guei Lin
An Improvement Of Wave Refraction-Diffraction Effect In Swan, Aw-Guei Lin
Journal of Marine Science and Technology
SWAN, a wind wave model, has been modified to take into account wave refraction-diffraction effects from the extended mild-slope equation when wind waves pass through a extremely uneven sea bottom in the presence of current. In our modified model, the diffraction correction parameter introduced by Holthuijsen et al. [10] has been adjusted to better predict the combined effect of the higher-order bottom effect, wave-bottom interaction and wave-current interaction. After a preliminary analysis, the influence of the correction parameter is discussed, and a comparison is made between the original and the new phase-decoupled versions of SWAN through some typical examples of …
An Experimental Study Of Regular Long Crested Waves Over A Crescent Type Shoal, Wen-Kai Weng, Jaw-Guei Lin, Chun-Sien Hsiao
An Experimental Study Of Regular Long Crested Waves Over A Crescent Type Shoal, Wen-Kai Weng, Jaw-Guei Lin, Chun-Sien Hsiao
Journal of Marine Science and Technology
Converting the ocean wave energy into electric power is one possibility of the development of alternative and nonpolluting sources of energy. Many researches concerning converters and their converting efficiency of wave power were developed and discussed in the last years. However, converting wave energy into electric power does not only depend upon converting system but condition of sea state essentially. A calm sea state with lower wave energy is difficult to drive converting device working and is unable to satisfy the minimum economical requirement. Unfortunately, wave heights in the sea state around Taiwan are mostly too smaller to extract the …
Numerical Simulations And Wind Tunnel Studies Of Pollutant Dispersion In The Urban Street Canyons With Different Height Arrangements, Cheng-Hsin Chang, Jin-Shian Lin, Chii-Ming Cheng, Yung-Shan Hong
Numerical Simulations And Wind Tunnel Studies Of Pollutant Dispersion In The Urban Street Canyons With Different Height Arrangements, Cheng-Hsin Chang, Jin-Shian Lin, Chii-Ming Cheng, Yung-Shan Hong
Journal of Marine Science and Technology
Air pollution in big city areas resulting from exhaust emissions is a major urban problem. Often traffic pollution excess controls air pollution management decisions. There are a number of elaborate predictive models of pollutant dispersion and diffusion that address the effects of variable shapes of city buildings on pollutant concentrations, but few are fully validated. This study presents ventilation behavior in different street canyon configurations. To evaluate dispersion in a model urban street canyon, a series of tests with various street canyons with different height in upwind and downwind of street canyon are presented. These buildings were arranged in 2-D …
Vibration Suppression Of Train-Induced Multiple Resonant Responses Of Two-Span Continuous Bridges Using Ve Dampers, Ying-Jie Wang, Jong-Dar Yau, Qing-Chao Wei
Vibration Suppression Of Train-Induced Multiple Resonant Responses Of Two-Span Continuous Bridges Using Ve Dampers, Ying-Jie Wang, Jong-Dar Yau, Qing-Chao Wei
Journal of Marine Science and Technology
This paper presents a study of reducing multiple resonant peaks of high-speed trains traveling over a two-span continuous railway bridge using visco-elastic (VE) dampers. The moving train is modeled as a series of two-degree-of-freedom (2 DOF) moving oscillators with identical intervals and the two-span continuous bridge as a Bernoulli-Euler beam with uniform span. Because of closely spaced frequencies of a continuous beam, the first several frequencies of the bridge would be excited to resonance during the passage of moving trains, which may result in multiple resonant peaks appearing on the response of train-bridge system. In order to reduce the multiple …
Criteria For The Initiation Of Modes Of Response Of A Caisson Subjected To A Breaking Wave Force, Jaw Guei Lin, Chi Chao David Tung
Criteria For The Initiation Of Modes Of Response Of A Caisson Subjected To A Breaking Wave Force, Jaw Guei Lin, Chi Chao David Tung
Journal of Marine Science and Technology
This paper concerns problems of a caisson subjected to a breaking wave force: (1) what are the possible modes of response and (2) the conditions initiate into these modes. These two questions have not been studied. The objective of this paper is to answer these two questions. However, the actual response of a caisson that takes place in each mode is not addressed in this study. A caisson placed on a horizontal frictional base, subjected to a concentrated horizontal force of short duration, applied to the seaward side face of the caisson and accompanied by a corresponding uplift force on …
Carbonation Service Life Prediction Of Existing Concrete Viaduct/Bridge Using Time-Dependent Reliability Analysis, Ming-Te Liang, Ran Huang, Shen-Ann Fang
Carbonation Service Life Prediction Of Existing Concrete Viaduct/Bridge Using Time-Dependent Reliability Analysis, Ming-Te Liang, Ran Huang, Shen-Ann Fang
Journal of Marine Science and Technology
This paper examines the predicted carbonation life of an existing concrete viaduct/bridge in the atmospheric environment based on probability and reliability indices. The probability is dependent upon the carbonation rate, carbonation remainder, concrete quality, and concrete cover. The carbonation life is defined as the service life of reinforced concrete (RC) or prestressed concrete (PC) structure at the beginning of time of steel corrosion when concrete cover surfers from carbonation and loses the protection function to steel. The carbonation life is equivalent to the initiation time of corrosion of reinforcement. Both the Chorng-ching viaduct and Wannfwu bridge were offered as illustrative …