Browsing by Author "Chiu, YF"

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Development and comparison of different methods of monitoring network design based on co-kriging
(1998)
Chang, LC
;
Chiu, YF
;
土木工程學系
;
Department of Civil Engineering
This study develops and compares several network design methods for groundwater monitoring based on the geostatistics theory and optimization schemes. Depending on the optimization structure, those methods are classified as sequential design model, branch and bound model, and non-linear programming model. The sequential design model extends the variance reduction method proposed by Rouhani in 1985. Theoretically, it is not a truly optimal design scheme. On the other hand, the branch and bound model, as proposed by Ben-Jemaa et al. in 1994 can compute a global optimal solution; however, it requires much mon computation than the sequential design model. The non-linear programming method, extending the methods proposed by Lin in 1995, can search the optimal locations of the monitoring wells within the planning area without pre-defining a set of available sites, in addition, the solution is local optimal. In this study, we applied those methods to the network planning in the Ping-Tung Plain of southern Taiwan. According to our results, the differences of the solutions for different models decrease with an increase of all the monitoring wells. Owing to its efficiency and flexibility, the sequential design model is the most practical method in general application, although the solution is not necessarily optimal.
Estimation of water particle velocities by empirical transfer function
(1997-01-01)
Chiu, YF
;
Kuo, YY
;
土木工程學系
;
Department of Civil Engineering
In previous and this studies it appears that the linear and nonlinear wave theory-can not accurately and easily predict the water particle velocities: Therefore, different from the theoretical considerations, in this study we have attempted to determine the transfer function empirically. Laboratory experiments were performed under various wave conditions. The empirical formulas of the transfer function of the wave height, angular frequency and water particle velocity were obtained on the basis of these test data by dimensional analysis and regression analysis. In intermediate and deep water depth conditions, the transfer function was only a function of a nondimensional parameter which is composed of the angular frequency, the depth of the velocity gauge under the still water level, water depth and the acceleration of gravity. Finally, the empirical formulas were compared with experimental data and observational data form present and Cavaleri's (1978) studies. The empirical formulas were found to be in sufficient correltion with these data.
Estimation of water particle velocities by empirical transfer function
(1997-01-01)
Chiu, YF
;
Kuo, YY
;
土木工程學系
;
Department of Civil Engineering
In previous and this studies it appears that the linear and nonlinear wave theory-can not accurately and easily predict the water particle velocities: Therefore, different from the theoretical considerations, in this study we have attempted to determine the transfer function empirically. Laboratory experiments were performed under various wave conditions. The empirical formulas of the transfer function of the wave height, angular frequency and water particle velocity were obtained on the basis of these test data by dimensional analysis and regression analysis. In intermediate and deep water depth conditions, the transfer function was only a function of a nondimensional parameter which is composed of the angular frequency, the depth of the velocity gauge under the still water level, water depth and the acceleration of gravity. Finally, the empirical formulas were compared with experimental data and observational data form present and Cavaleri's (1978) studies. The empirical formulas were found to be in sufficient correltion with these data.
Roles of non-structural walls in Chi-Chi Earthquake
(2002-07-01)
Liou, GS
;
Chiu, YF
;
Cheng, FP
;
土木工程學系
;
Department of Civil Engineering
Presented are some close observations of failure modes of building structures after the Chi-Chi Earthquake, which occurred on September 21, 1999, and some numerical analysis of building structures that proves the conclusions of these close observations. According to the observations and analysis results, one can conclude that non-structural walls play a major role in the damage and collapse of building structures in strong earthquakes. Therefore, some suggestions are made for the structural design industry and academic research in order to improve the earthquake resistance of existing and future building structures.