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The neuro‐controller training algorithm based on cost function is applied to a multi‐degree‐of‐freedom system; and a sensitivity evaluation algorithm replacing the emulator neural network is proposed. In conventional methods, the emulator neural network is used to evaluate the sensitivity of structural response to the control signal. To use the emulator, it should be trained to predict the dynamic response of the structure. Much of the time is usually spent on training of the emulator. In the proposed algorithm, however, it takes only one sampling time to obtain the sensitivity. Therefore, training time for the emulator is eliminated. As a result, only one neural network is used for the neuro‐control system. In the numerical example, the three‐storey building structure with linear and non‐linear stiffness is controlled by the trained neural network. The actuator dynamics and control time delay are considered in the simulation. Numerical examples show that the proposed control algorithm is valid in structural control. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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This study presents a probabilistic neural network (PNN) technique for predicting the stability number of armor blocks of breakwaters. The PNN is prepared using the experimental data of Van der Meer. The predicted stability numbers of the PNN are compared with those of previous studies, i.e. by an empirical formula and a previous neural network model. The agreement index between the measured and predicted stability numbers by PNN are better than those by the previous studies. The PNN offers a way to interpret the network's structure in the form of a probability density function and it is easy to implement. Therefore, it can be an effective tool for designers of rubble mound breakwaters. 相似文献
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Dong Hyawn KIM 《中国海洋工程》2014,(6):739-748
A new load surface based approach to the reliability analysis of caisson-type breakwater is proposed. Uncertainties of the horizontal and vertical wave loads acting on breakwater are considered by using the so-called load surfaces, which can be estimated as functions of wave height, water level, and so on. Then, the first-order reliability method（FORM） can be applied to determine the probability of failure under the wave action. In this way, the reliability analysis of breakwaters with uncertainties both in wave height and in water level is possible. Moreover, the uncertainty in wave breaking can be taken into account by considering a random variable for wave height ratio which relates the significant wave height to the maximum wave height. The proposed approach is applied numerically to the reliability analysis of caisson breakwater under wave attack that may undergo partial or full wave breaking. 相似文献
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Dong Hyawn KIM 《海洋工程》2017,31(3):317-321
Evaluating the expected sliding distance of a vertical slit caisson breakwater is proposed. Time history for the wave load to a vertical slit caisson is made. It consists of two impulsive wave pressures followed by a smooth sinusoidal pressure. In the numerical analysis, the sliding distance for an attack of single wave was shown and the expected sliding distance during 50 years was also presented. Those results were compared with a vertical front caisson breakwater without slit. It was concluded that the sliding distance of a vertical slit caisson may be over-estimated if the wave pressure on the caisson is evaluated without considering vertical slit. 相似文献
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In this study,an advanced probabilistic neural network(APNN)method is proposed to reflect the global probability density function(PDF)by summing up the heterogeneous local PDF which is automatically determined in the individual standard deviation of variables.The APNN is applied to predict the stability number of armor blocks of breakwaters using the experimental data of van der Meer,and the estimated results of the APNN are compared with those of an empirical formula and a previous artificial neural network(ANN)model.The APNN shows better results in predicting the stability number of armor blocks of breakwater and it provided the promising probabilistic viewpoints by using the individual standard deviation in a variable. 相似文献
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Ju Myung KIM Dong Hyawn KIM Gyu Won LEE 《中国海洋工程》2006,20(2):259-268
1.IntroductionAmong various control devices,Tuned Mass Damper(TMD)has been mostfrequently usedtothecontrol of structural vibration induced by oscillating loads such as earthquakes,winds,and waves.This is due to the fact that it operates without external e… 相似文献
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A new method of treating maximum wave height as a random variable in reliability analysis of breakwater caissons is proposed. The maximum wave height is expressed as the significant wave height multiplied by the so-called wave height ratio. The proposed wave height ratio is a type of transfer function from the significant wave height to the maximum wave height. Under the condition of a breaking wave, the ratio is intrinsically nonlinear. Therefore, the probability density function for the variable cannot be easily defined. In this study, however, it can be derived from the relationship between the maximum and significant waves in a nonbreaking environment. Some examples are shown to validate the derived probability density function for the wave ratio parameter. By introducing the wave height ratio into reliability analysis of caisson breakwater, the maximum wave height can be used as an independent and primary random variable, which means that the risk of caisson failure during its lifetime can be evaluated realistically. 相似文献
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Dong Hyawn KIM Taerim KIM 《中国海洋工程》2014,28(5):579-586
A new method of treating maximum wave height as a random variable in reliability analysis of breakwater caissons is proposed. The maximum wave height is expressed as the significant wave height multiplied by the so-called wave height ratio.The proposed wave height ratio is a type of transfer function from the significant wave height to the maximum wave height.Under the condition of a breaking wave, the ratio is intrinsically nonlinear. Therefore, the probability density function for the 相似文献
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