A New Methodology For Deriving Regional Time Of Concentration Equations Using GIS And Genetic Programming

Time of concentration (ToC) is the most frequently utilized time-scale parameter in hydrology which must be estimated accurately to ensure correct simulation of many different hydrological processes. Hydrologists have developed many empirical and semi-empirical methods for estimating ToC which are regional, watershed, and site-specific. Modellers are often confused by the number of ToC estimation methods and formulas and often select an equation without evaluating its correctness which leads to inaccurate simulation results. The importance of deriving and using regional ToC equations has been highlighted in many studies. In this paper, a methodology is proposed for deriving ToC equation(s) for watersheds located in a specific geographic region using GIS and Genetic Programming (GP). The use of GIS data allows for easy extraction of multiple characteristics of a large number of watersheds and sub-watersheds. Also, integration of GIS maps into the TR-55 model enables the determination of “true” TOC values for the watersheds under study. The obtained physical and hydrological characteristics of the watersheds are combined with rainfall characteristics and computed ToC values to form a large database. GP is then used as a data mining tool for conducting symbolic regression and deriving the most accurate set of equations for the watersheds of the region. In a case study, the proposed methodology is applied to 72 watersheds and sub-watersheds in Khorasan Razavi province, Iran. The method provides a set of different ToC equations to be used for watersheds with different sizes in the region. The equations proposed by GP are evaluated and compared to other conventional ToC estimation methods. The set of equations found by GP provides insight on the relationship between ToC and other watershed and rainfall characteristics and highlights the potential role of GP as an attractive and effective Knowledge Discovery tool

Turbulence structure in bottom layer of a tidal estuary

River hydrodynamicsTurbulent open channel flow and transport phenomen

Response of S.C.704 maize hybrid seed production to planting pattern

In order to determine the best planting pattern for producing the S.C.704 hybrid seed of maize, a field experiment was conducted in 2007 at Safiabad Dezful Research Center via a complete block design with four treatments and replicates each. The treatments were: D1 (one row each of paternal and maternal lines), D2 (two rows of paternal line and one row of maternal line), D3 (two rows each of paternal and maternal lines) and D4 (one row of paternal line and two rows of maternal line). The result indicates that planting pattern has a significant effect on most of the characteristics of corn studied. Ear weight, seed weight on ear (maximum 97 g), ear weight ratio, seed weight, cob weight ratio (maximum 66%) and grain yield increased with differences from one row planting pattern to two row planting pattern. So, varying the planting pattern from one-row pattern to two-row pattern increased some of the characteristics, though there were no significant differences between one and two-row planting patterns. The fourth treatment (one row of paternal line and two rows of maternal line planting pattern) was the best on grain yield (2,753 kg/ha).Keywords: Planting pattern, seed produce, corn grain, S.C.704 hybri

A New Method for Fault Current Limiting and Voltage Compensating in Power Systems Using Active Superconducting Current Controller

In this paper, a new method for both fault current limiting and voltage compensating using Active Superconducting Current Controller (ASCC) is proposed. The main objective of this paper is to present an appropriate control strategy for ASCC to achieve both the fault current limiting and voltage compensation purposes. Three different operating modes are defined for ASCC including normal mode, fault current limiting mode, and voltage compensation mode and a proper control strategy is designed for each mode. For the fault current limiting, the model of a typical three-phase system with ASCC is simulated and different states for current limiting in different levels are defined. Also, for the voltage compensating mode, the PI model for the line is considered and the line transmission matrix is obtained when the ASCC is connected at the sending end and middle of the line. Finally, proper settings for ASCC are determined such that the magnitude of the receiving end and the sending end voltages become equal. Simulation results using MATLAB software confirm the proper performance of the proposed method

Application of Acoustic Tomography for Gaging Discharge of Atidally Dominated River

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv