Estimation of soil erosion rates in a subtropical mountain watershed using 137Cs radionuclide     

Yu-Jia Chiu  Kang-Tsung Chang  Yi-Chin Chen  Jiunn-Hsing Chao  Hong-Yuan Lee 《Natural Hazards》2011,59(1):271-284

The formulation of watershed management strategies to protect water resources threatened by soil erosion and sedimentation requires a thorough understanding of sediment sources and factors that drive soil movement in the watershed. This paper describes a study of medium-term water-driven soil erosion rates in a mountainous watershed of the Shihmen Reservoir in Taiwan. A total of 60 sampling sites were selected along a hillslope. At each sampling site, the inventory ¹³⁷Cs activity was determined and then calculated with the diffusion and migration model to derive soil erosion rates. The rates are one to two orders of magnitude lower than estimates using the Universal Soil Loss Equation, a soil erosion model often used in Taiwan. Results of multiple regression analysis indicate that the spatial variability of soil erosion rates is associated with the relative position of a sampling site to the nearest ridge and soil bulk densities (r ² = 0.33, p < 0.01). Finally, the patterns of soil redistribution rates on the hillslope follow the ¹³⁷Cs hillslope model as soil erosion increases in the downslope direction. No deposition site is found at footslope because soil deposition is swept away by regular flooding along the stream channel. This study is an important first step in using ¹³⁷Cs as a tracer of soil redistribution in mountainous watersheds of Taiwan.  相似文献   

Sedimentology of early Pliocene sandstones in the south-western Taiwan foreland: Implications for basin physiography in the early stages of collision     

Sébastien Castelltort  Stefan Nagel  Frédéric Mouthereau  Andrew Tien-Shun Lin  Andreas Wetzel  Boris Kaus  Sean Willett  Shao-Ping Chiang  Wei-Yi Chiu 《Journal of Asian Earth Sciences》2011,40(1):52-71

This work presents sedimentological observations and interpretations on three detailed sections of the Pliocene Yutengping/Ailiaochiao formations, deposited in the early stages of collision in Taiwan. Seven facies associations record paleoenvironments of deposition ranging from nearshore to lower offshore with a strong influence of tidal reworking, even in shelfal sub-tidal environments, and a pro-delta setting characterized by mass-flows. The association of shallow facies of the upper offshore to lower shoreface with pro-delta turbidite facies sourced in the orogen to the east suggests a peculiar setting in which turbidite deposition occurred below wave base but on the shelf, in water depths of probably less than 100 m. This adds to the examples of “shallow turbidites” increasingly commonly found in foreland basins and challenges the classical view of a “deep” early underfilled foreland basin. Time series analysis on tidal rhythmites allow us to identify a yearly signal in the form of periodic changes of sand-supply, energy and bioturbation that suggests a marked seasonality possibly affecting precipitation and sediment delivery as well as temperature. The Taiwan foreland basin may also present a potentially high-resolution record in shallow sediments of the early installation of monsoonal circulation patterns in east Asia. We confirm partly the paleogeography during the early stages of collision in Taiwan: the Chinese margin displayed a pronounced non-cylindrical geometry with a large basement promontory to the west in place of the modern Taiwan mountain range. Collision in Taiwan may have happened at once along the whole length of the modern mountain range, instead of progressively from north to south as classically considered.  相似文献   

Navigating ethnicity: segregation,placemaking, and difference     

Francesca Chiu 《Urban geography》2019,40(4):582-583

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Internal solitons in the northeastern south China Sea. Part I: sources and deep water propagation   总被引：11，自引：0，他引：11  

Ramp  S.R. Tswen Yung Tang Duda  T.F. Lynch  J.F. Liu  A.K. Ching-Sang Chiu Bahr  F.L. Hyoung-Rok Kim Yang  Y.-J. 《Oceanic Engineering, IEEE Journal of》2004,29(4):1157-1181

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Design of a sliding mode fuzzy controller for the guidance and control of an autonomous underwater vehicle   总被引：1，自引：0，他引：1  

J. Guo  F. -C. Chiu  C. -C. Huang 《Ocean Engineering》2003,30(16):2137-2155

This work demonstrates the feasibility of applying a sliding mode fuzzy controller to motion control and line of sight guidance of an autonomous underwater vehicle. The design method of the sliding mode fuzzy controller offers a systematical means of constructing a set of shrinking-span and dilating-span membership functions for the controller. Stability and robustness of the control system are guaranteed by properly selecting the shrinking and dilating factors of the fuzzy membership functions. Control parameters selected for a testbed vehicle, AUV-HM1, are evaluated through tank and field experiments. Experimental results indicate the effectiveness of the proposed controller in dealing with model uncertainties, non-linearities of the vehicle dynamics, and environmental disturbances caused by ocean currents and waves.  相似文献   

Optimizing the reservoir operating rule curves by genetic algorithms     

Fi‐John Chang  Li Chen  Li‐Chiu Chang 《水文研究》2005,19(11):2277-2289

Genetic algorithms, founded upon the principle of evolution, are applicable to many optimization problems, especially popular for solving parameter optimization problems. Reservoir operating rule curves are the most common way for guiding and managing the reservoir operation. These rule curves traditionally are derived through intensive simulation techniques. The main aim of this study is to investigate the efficiency and effectiveness of two genetic algorithms (GAs), i.e., binary coded and real coded, to derive multipurpose reservoir operating rule curves. The curves are assumed to be piecewise linear functions where the coordinates of their inflection points are the unknowns and we want to optimize system performance. The applicability and effectiveness of the proposed methods are tested on the operation of the Shih‐Men reservoir in Taiwan. The current M‐5 operating curves of the Shih‐Men reservoir are also evaluated. The results show that the GAs provide an adequate, effective and robust way for searching the rule curves. Both sets of operating rule curves obtained from GAs have better performance, in terms of water release deficit and hydropower, than the current M‐5 operating rule curves, while the real‐coded GA is more efficient than the binary‐coded GA. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Linking a prolonged Neo‐Tethyan magmatic arc in South Asia: Zircon U‐Pb and Hf isotopic constraints from the Lohit Batholith,NE India     

Te‐Hsien Lin  Sun‐Lin Chung  Anil Kumar  Fu‐Yuan Wu  Han‐Yi Chiu  I‐Jhen Lin 《地学学报》2013,25(6):453-458

The Neo‐Tethyan subduction that operated before the India‐Asia collision resulted in an Andean‐type convergent margin in South Asia and was associated with extensive arc magmatism that formed the Transhimalayan batholiths. Magmatism in the Gangdese Batholith, the largest batholith exposed in the Lhasa terrane of southern Tibet, is considered to have lasted from the early Jurassic to Eocene. However, eastward correlation of the Gangdese Batholith is uncertain because it is truncated by the eastern Himalayan syntaxis. Here, we report new data from the Lohit Batholith, NE India, including: (i) zircon U‐Pb ages of five granitoids from ca. 148 to 96 Ma; and (ii) zircon Hf isotopes of these rocks that yield high and positive ε_Hf(T) values. We argue that the Lohit Batholith is the eastward extension of the Gangdese Batholith, and can be correlated southward to the Wuntho‐Popa arc in West Burma, thus linking a prolonged Neo‐Tethyan magmatic arc system from southern Tibet to Southeast Asia.  相似文献   

Marine 3D seismic volumes from 2D seismic survey with large streamer feathering     

Lin  Liang-Fu  Hsu  Ho-Han  Liu  Char-Shine  Chao  Kuo-Han  Ko  Chia-Chun  Chiu  Shye-Dong  Hsieh  Hsin-Sung  Ma  Yu-Fang  Chen  Song-Chuen 《Marine Geophysical Researches》2019,40(4):619-633

Marine Geophysical Research - Strong ocean current influences a marine seismic survey and forces the streamer off-course from the survey line. The sideway drift of the streamer results in that the...  相似文献   

Intelligent control for modeling of real‐time reservoir operation,part II: artificial neural network with operating rule curves     

Ya‐Ting Chang  Li‐Chiu Chang  Fi‐John Chang 《水文研究》2005,19(7):1431-1444

To bridge the gap between academic research and actual operation, we propose an intelligent control system for reservoir operation. The methodology includes two major processes, the knowledge acquired and implemented, and the inference system. In this study, a genetic algorithm (GA) and a fuzzy rule base (FRB) are used to extract knowledge based on the historical inflow data with a design objective function and on the operating rule curves respectively. The adaptive network‐based fuzzy inference system (ANFIS) is then used to implement the knowledge, to create the fuzzy inference system, and then to estimate the optimal reservoir operation. To investigate its applicability and practicability, the Shihmen reservoir, Taiwan, is used as a case study. For the purpose of comparison, a simulation of the currently used M‐5 operating rule curve is also performed. The results demonstrate that (1) the GA is an efficient way to search the optimal input–output patterns, (2) the FRB can extract the knowledge from the operating rule curves, and (3) the ANFIS models built on different types of knowledge can produce much better performance than the traditional M‐5 curves in real‐time reservoir operation. Moreover, we show that the model can be more intelligent for reservoir operation if more information (or knowledge) is involved. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Laboratory Simulations of Bow Shocks and Magnetospheres     

W. Horton  C. Chiu  T. Ditmire 《Astrophysics and Space Science》2005,298(1-2):395-401

Laboratory experiments using a plasma wind generated by laser-target interaction are proposed and analyzed to investigate the creation of a shock in front of the magnetosphere and the dynamo mechanism. The proposed experiments and simulations are thought to be relevant to understanding the electron acceleration mechanisms at work in shock-driven magnetic dipole confined plasma in compact magnetized stars.  相似文献