Rainfall network design using kriging and entropy   总被引：4，自引：0，他引：4  

Yen‐Chang Chen  Chiang Wei  Hui‐Chung Yeh 《水文研究》2008,22(3):340-346

The spatial distribution of rainfall is related to meteorological and topographical factors. An understanding of the weather and topography is required to select the locations of the rain gauge stations in the catchment to obtain the optimum information. In theory, a well‐designed rainfall network can accurately represent and provide the needed information of rainfall in the catchment. However, the available rainfall data are rarely adequate in the mountainous area of Taiwan. In order to provide enough rainfall data to assure the success of water projects, the rainfall network based on the existing rain gauge stations has to be redesigned. A method composed of kriging and entropy that can determine the optimum number and spatial distribution of rain gauge stations in catchments is proposed. Kriging as an interpolator, which performs linear averaging to reconstruct the rainfall over the catchment on the basis of the observed rainfall, is used to compute the spatial variations of rainfall. Thus, the rainfall data at the locations of the candidate rain gauge stations can be reconstructed. The information entropy reveals the rainfall information of the each rain gauge station in the catchment. By calculating the joint entropy and the transmitted information, the candidate rain gauge stations are prioritized. In addition, the saturation of rainfall information can be used to add or remove the rain gauge stations. Thus, the optimum spatial distribution and the minimum number of rain gauge stations in the network can be determined. The catchment of the Shimen Reservoir in Taiwan is used to illustrate the method. The result shows that only seven rain gauge stations are needed to provide the necessary information. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Performance-based concept on seismic evaluation of existing bridges   总被引：1，自引：0，他引：1  

W.Phillip Yen 《地震工程与工程振动(英文版)》2009,8(1):127-135

Conventional seismic evaluation of existing bridges explores the ability of a bridge to survive under significant earthquake excitations. This approach has several major drawbacks, such as only a single structural performance of near collapse is considered, and the simplified approach of adopting strength-based concept to indirectly estimate the nonlinear behavior of a structure lacks accuracy. As a result, performance-based concepts that include a wider variety of structural performance states of a given bridge excited by different levels of earthquake intensity is needed by the engineering community. This paper introduces an improved process for the seismic evaluation of existing bridges. The relationship between the overall structural performance and earthquakes with varying levels of peak ground acceleration (PGA) can successfully be linked. A universal perspective on the seismic evaluation of bridges over their entire life-cycle can be easily obtained to investigate multiple performance objectives. The accuracy of the proposed method, based on pushover analysis, is proven in a case study that compares the results from the proposed procedure with additional nonlinear time history analyses.  相似文献   

井水位振荡试验及其结果   总被引：3，自引：1，他引：3       下载免费PDF全文

张昭栋  郑香媛 《地震地质》1992,14(2):183-188

通过鲁04井的频率特性试验,求出了该井含水层系统的频率特性参数,固有振动周期为40.59s,阻尼系数为0.0362s-1。并且计算出鲁04井含水层的导水系数为1.8×10-3m2/s。利用这些结果解释了鲁04井对地震波响应比珍珠泉井差的原因  相似文献   

风向与树木之生长     

严振飞 《气象学报》1936,12(7):369-370

剖树木干部之断面,察其年轮之多少,约略可知其生长年代之久暂。由年轮之疏密,可考究其历年雨量之丰歉,因雨量丰沛,则滋长旺盛,年轮宽阔;若雨量稀少,则发育迟缓,年轮密狭,适与一寒一暑情形相似。此不过考究树体内部之组织,而与研究气候学者,以探  相似文献   

A laboratory investigation into the settlement of a foundation on geogrid-reinforced sand due to cyclic load     

B. Yeo  S. C. Yen  V. K. Puri  B. M. Das  M. A. Wright 《Geotechnical and Geological Engineering》1993,11(1):1-14

Summary Laboratory model test results for permanent settlement of a shallow square foundation supported by geogrid-reinforced sand and subjected to cyclic loading are presented. During the application of the cyclic load, the foundation was subjected to a sustained static load. Tests were conducted with only one type of geogrid and at one relative density of compaction of sand. Based on the model test results, the nature of variation of the permanent settlement of the foundation with the intensity of the static loading and the amplitude of the cyclic load intensity are presented in a non-dimensional form.  相似文献   

A direct determination of the oxygen isotope fractionation between quartz and magnetite at 600 and 800°C and 5 kbar     

William F Downs  Yen Touysinhthiphonexay  Peter Deines 《Geochimica et cosmochimica acta》1981,45(11):2065-2072

The partitioning of oxygen isotopes between quartz and magnetite was measured at 600 and 800 C and 5 kbar, using an internally heated pressure vessel equipped with a Shaw-membrane. Through adjustment of the hydrogen fugacity the starting material, fayalite, was decomposed to form quartz and magnetite. The isotopic composition difference between the separated quartz and magnetite fraction was measured directly. As the mineral separates were not completely pure, a correction was applied to the measured fractionations. The independence of the measured isotopic composition differences of run length, the initial isotopic composition of the starting materials as well as the isotopic composition difference between them suggests that the fractionations, 1000 In α_Q-M = 7.8 ± 0.4% at 600°C and 1000 In α_Q-M = 6.1 ± 0.2% at 800°C, represent equilibrium values.  相似文献   

Contribution of E.S.R. analysis toward diagenic mechanisms in bituminous deposits     

T.F. Yen  S.R. Sprang 《Geochimica et cosmochimica acta》1977,41(8):1007-1018

The E.S.R. g-values of a variety of bituminous materials have been plotted against a function of their heteroatom content ∑δ_κX_κ, where δ is the splitting coefficient of the given heteroatom κ, and X is its atomic fraction. Three discrete series are evident: two coal series, one exhibiting direct variation of g with ∑δ_κX_κ (Series I), the other exhibiting an inverse relationship (Series II). The petroleum asphaltenes, as well as most asphaltites and asphaltoids (Series III), lie above and roughly parallel to Series I. Sulfur-treated asphaltics approach Series I, whereas heated asphaltenes and resins are situated around the intersection of Series II and III.Bituminous deposits may transform through diagenesis to their mature forms, as evidenced by their increase in the delocalization (increased aromaticity) with a decrease in heteroatom content. The diagenesis of coal is reliant on oxygen whose elimination may result in aromatization (Series I), and further transformations may increase active peripheral oxygen function groups (Series II). The intersection of Series I and II contains the delocalization states. There exist major differences in the precursors and mode of transformation between members of the coal and asphaltene series.  相似文献   

Simulation of the seismic performance of the Bolu Viaduct subjected to near‐fault ground motions     

S. W. Park  H. Ghasemi  J. Shen  P. G. Somerville  W. P. Yen  M. Yashinsky 《地震工程与结构动力学》2004,33(13):1249-1270

The seismic performance of the Bolu Viaduct in the Duzce, Turkey, earthquake of November 1999 was studied via a non‐linear, time‐history analysis of a multi‐degree of freedom model. The viaduct had a seismic isolation system consisting of yielding‐steel energy dissipation units and sliding pot bearings. The Duzce earthquake caused a surface rupture across the viaduct, which resulted in excessive superstructure movement and widespread failure of the seismic isolation system. The effect of the rupture was modeled by a static, differential ground displacement in the fault‐parallel direction across the rupture. The ground motions used in the analysis contain common near‐fault features including a directivity pulse in the fault‐normal direction and a fling step in the fault‐parallel direction. The analysis used a finite element package capable of modeling the mechanical behavior of the seismic isolation system and focused on the structural response of a 10‐span module of the viaduct. This analysis showed that the displacement of the superstructure relative to the piers exceeded the capacity of the bearings at an early stage of the earthquake, causing damage to the bearings as well as to the energy dissipation units. The analysis also indicated that shear keys, both longitudinal and transverse, played a critical role in preventing collapse of the deck spans. Published in 2004 by John Wiley & Sons, Ltd.  相似文献   

Seismic isolation of viaduct piers by means of a rocking mechanism     

Yi‐Hsuan Chen  Wei‐Hsin Liao  Chien‐Liang Lee  Yen‐Po Wang 《地震工程与结构动力学》2006,35(6):713-736

  相似文献   

Reservoir operation using grey fuzzy stochastic dynamic programming     

Fi‐John Chang  Shyh‐Chi Hui  Yen‐Chang Chen 《水文研究》2002,16(12):2395-2408

This paper presents an optimal regulation programme, grey fuzzy stochastic dynamic programming (GFSDP), for reservoir operation. It is composed of a grey system, fuzzy theory and dynamic programming. The grey system represents data by covering the whole range without loss of generality, and the fuzzy arithmetic takes charge of the rules of reservoir operation. The GFSDP deals with the multipurpose decision‐making problem by fuzzy optimization theorem. The practicability and effectiveness of the proposed approach is tested on the operation of the Shiman reservoir in Taiwan. The current M5 operating rule curves of this reservoir also are evaluated. The simulation results demonstrate that this new approach, in comparison with the M5 rule curves, has superior performance with regard to the total water deficit and number of monthly deficits. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献