四湖排水系统运行规划优化模型

分析了四湖排水系统的运行特点,应用大系统理论对系统进行了递阶分析并确定了该系统运行规划的NLP/DP/LP优化模型结构。在确定系统运行规则的基础上,分层建立了系统运行规划优化模型。     

Development of a river delta: a case study of Cimanuk river mouth,Indonesia

This paper describes delta development processes with particular reference to Cimanuk Delta in Indonesia. Cimanuk river delta, the most rapidly growing river delta in Indonesia, is located on the northern coast of Java Island. The delta is subject to ocean waves of less than 1 m height due to its position in the semi‐enclosed Java Sea in the Indonesian archipelago. The study has been carried out using a hydrodynamic model that accounts for sediment movement through the rivers and estuaries. As an advanced approach to management of river deltas, a numerical model, namely MIKE‐21, is used as a tool in the management of Cimanuk river delta. From calibration and verification of hydrodynamic model, it was found that the best value of bed roughness was 0·1 m. For the sediment‐transport model, the calibration parameters were adjusted to obtain the most satisfactory results of suspended sediment concentration and volume of deposition. By comparing the computed and observed data in the calibration, the best values of critical bed shear stress for deposition, critical bed shear stress for erosion and erosion coefficient were 0·05 N m^?2, 0·15 N m^?2, and 0·00001 kg m^?2 s^?1, respectively. The calibrated model was then used to analyse sensitivity of model parameters and to simulate delta development during the periods 1945–1963 and 1981–1997. It was found that the sensitive model parameters were bed shear stresses for deposition and erosion, while the important model inputs were river suspended sediment concentration, sediment characteristics and hydrodynamic. The model result showed reasonable agreement with the observed data. As evidenced by field data, the mathematical model proves that the Cimanuk river delta is a river‐dominated delta because of its protrusion pattern and very high sediment loads from the Cimanuk river. It was concluded that 86% of sediment load from the Cimanuk river was deposited in the Cimanuk delta. Copyright © 2008 John Wiley & Sons, Ltd.     

Non-Darcian groundwater flow in leaky aquifers

Abstract

A simplified method has been developed for solving leaky aquifer non-Darcian flow hydraulics. The principle of volumetric approach is combined with the confined-aquifer, time-dependent drawdown equation in an observation well. The groundwater flow in the leaky aquifer is assumed to obey a non-Darcian flow law of exponential type. The results are obtained in the form of type-curve expressions from which the necessary bundles of curves are drawn for a set of selective non-Darcian flow aquifer parameters. Although application of the methodology appears as rather limited but it provides a scientific contribution and extension of leaky aquifer theory towards nonlinear flow conditions. The methodology developed herein is applied to some actual field data from the eastern sedimentary basin in the Kingdom of Saudi Arabia.     

模糊控制在直流变频空调器中的应用

从直流型变频空调器的特点及控制要求出发,提出了模糊控制系统的结构,讨论了直流变频空调器的模糊控制算法.对控制器的性能(主要是鲁棒性)进行了详细的分析,对所采用的模糊控制算法在Matlab平台下进行了仿真,作为比较同时给出了其他常用算法的仿真结果.     

A fuzzy dynamic flood routing model for natural channels

A fuzzy dynamic flood routing model (FDFRM) for natural channels is presented, wherein the flood wave can be approximated to a monoclinal wave. This study is based on modification of an earlier published work by the same authors, where the nature of the wave was of gravity type. Momentum equation of the dynamic wave model is replaced by a fuzzy rule based model, while retaining the continuity equation in its complete form. Hence, the FDFRM gets rid of the assumptions associated with the momentum equation. Also, it overcomes the necessity of calculating friction slope (S_f) in flood routing and hence the associated uncertainties are eliminated. The fuzzy rule based model is developed on an equation for wave velocity, which is obtained in terms of discontinuities in the gradient of flow parameters. The channel reach is divided into a number of approximately uniform sub‐reaches. Training set required for development of the fuzzy rule based model for each sub‐reach is obtained from discharge‐area relationship at its mean section. For highly heterogeneous sub‐reaches, optimized fuzzy rule based models are obtained by means of a neuro‐fuzzy algorithm. For demonstration, the FDFRM is applied to flood routing problems in a fictitious channel with single uniform reach, in a fictitious channel with two uniform sub‐reaches and also in a natural channel with a number of approximately uniform sub‐reaches. It is observed that in cases of the fictitious channels, the FDFRM outputs match well with those of an implicit numerical model (INM), which solves the dynamic wave equations using an implicit numerical scheme. For the natural channel, the FDFRM outputs are comparable to those of the HEC‐RAS model. Copyright © 2009 John Wiley & Sons, Ltd.     

New Methods of Fitting the Membership Function of Oceanic Water Masses

1　Introduction　Watermassanalysisisanimportantsubjectinphys icaloceanographystudies (PickardandEmery ,1 990 ;YeandLi,1 992 ) .Helland Hansenplottedin 1 91 6theT Scurve ,whichisafterwardsknownasoneoftheT Sdiagrams ,andsuggestedthatawatermasscanbedefinedby…     

基于模糊Hopfield神经网络的大气降水粒子分类

提出基于模糊Hopfield神经网络的大气降水粒子分类,它是通过计算样本间的模糊关系的相似程度,再加上Hopfield网络所特有的高稳定性,对大气降水粒子进行分类.通过对各降水粒子所对应雷达回波数据的分析,验证了方法的可行性.     

Storm‐event rainfall–runoff modelling approach for ungauged sites in Taiwan

This work develops a top‐down modelling approach for storm‐event rainfall–runoff model calibration at unmeasured sites in Taiwan. Twenty‐six storm events occurring in seven sub‐catchments in the Kao‐Ping River provided the analytical data set. Regional formulas for three important features of a streamflow hydrograph, i.e. time to peak, peak flow, and total runoff volume, were developed via the characteristics of storm event and catchment using multivariate regression analysis. Validation of the regional formulas demonstrates that they reasonably predict the three features of a streamflow hydrograph at ungauged sites. All of the sub‐catchments in the study area were then adopted as ungauged areas, and the three streamflow hydrograph features were calculated by the regional formulas and substituted into the fuzzy multi‐objective function for rainfall–runoff model calibration. Calibration results show that the proposed approach can effectively simulate the streamflow hydrographs at the ungauged sites. The simulated hydrographs more closely resemble observed hydrographs than hydrographs synthesized using the Soil Conservation Service (SCS) dimensionless unit hydrograph method, a conventional method for hydrograph estimation at ungauged sites in Taiwan. Copyright © 2008 John Wiley & Sons, Ltd.     

模糊评判法在公路黄土洞穴发育程度分区中的应用

阐述了影响黄土洞穴形成的黄土湿陷性、崩解性、地质构造、节理裂隙、微地形地貌和水文及气候条件等工程地质特性和地质因素;在公路沿线地区,公路工程质量及人类活动也是黄土洞穴形成的影响因素。洞穴发育程度分区预测和评价极具复杂性、随机性和模糊性,为此,在对各影响因素分析的基础上,借助模糊综合评判法,对黄土区公路沿线洞穴发育程度分区进行了研究。与实际情况对比分析表明,预测评价结果合理可靠,可作为黄土区已建公路洞穴灾害的防治依据。     

Adaptive fuzzy controller design for dynamic positioning system of vessels

This paper develops an adaptive fuzzy controller for the dynamic positioning (DP) system of vessels with unknown dynamic model parameters and unknown time-varying environmental disturbances. The controller is designed by combining the adaptive fuzzy system with the vectorial backstepping method. An adaptive fuzzy system is employed to approximate the uncertain term induced by unknown dynamic model parameters and unknown time-varying environmental disturbances. It is theoretically proved that the proposed adaptive fuzzy DP controller can make the vessel be maintained at the desired values of its position and heading with arbitrary accuracy, while guaranteeing the uniform ultimate boundedness of all signals in the closed-loop DP control system of vessels. Simulation studies with comparisons on a supply vessel are carried out, and the results illustrate the effectiveness of the proposed control scheme.