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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Simulation-based design of water harvesting schemes for irrigation

Heiler, Terence David January 1981 (has links)
New Zealand Agricultural Engineering Institute / Also published as: Agricultural Engineering Thesis no. 4 / For large areas of New Zealand that suffer from agricultural drought, the only practicable way of providing irrigation is through the use of water harvesting schemes that divert winter flood water in nearby streams into off-stream storages for irrigation use in the summer. A community water harvesting scheme is presently under construction in the Glenmark area of North Canterbury which was designed using traditional methods. The objectives of this thesis were to assess the limitations of traditional design methods for water harvesting schemes using the Glenmark Scheme as a case study and to develop an improved method based on a systems modelling approach. A daily simulation model was developed that incorporated in a realistic way the engineering, hydrologic, agronomic and economic features of importance to the design of water harvesting schemes in New Zealand. The model was used to study the adequacy of the traditional methods used for the design of the Glenmark Scheme; to arrive at alternative design solutions that achieved higher levels of engineering, agronomic and economic efficiency; and to develop a better understanding of the nature of complex water harvesting systems. It was demonstrated that compounding conservatism inherent in traditional design methods resulted in scheme overdesign and that the ability of the systems model to capture the essential dynamics of the system allowed higher levels of design performance to be achieved. The experience gained in the use of the systems model led to the development of a formalised design procedure for water harvesting schemes that represents an advance on methods hitherto available.
22

Developing Artificial Neural Networks (ANN) Models for Predicting E. Coli at Lake Michigan Beaches

Mitra Khanibaseri (9045878) 24 July 2020 (has links)
<p>A neural network model was developed to predict the E. Coli levels and classes in six (6) select Lake Michigan beaches. Water quality observations at the time of sampling and discharge information from two close tributaries were used as input to predict the E. coli. This research was funded by the Indiana Department of Environmental Management (IDEM). A user-friendly Excel Sheet based tool was developed based on the best model for making future predictions of E. coli classes. This tool will facilitate beach managers to take real-time decisions.</p> <p>The nowcast model was developed based on historical tributary flows and water quality measurements (physical, chemical and biological). The model uses experimentally available information such as total dissolved solids, total suspended solids, pH, electrical conductivity, and water temperature to estimate whether the E. Coli counts would exceed the acceptable standard. For setting up this model, field data collection was carried out during 2019 beachgoer’s season.</p> <p>IDEM recommends posting an advisory at the beach indicating swimming and wading are not recommended when E. coli counts exceed advisory standards. Based on the advisory limit, a single water sample shall not exceed an E. Coli count of 235 colony forming units per 100 milliliters (cfu/100ml). Advisories are removed when bacterial levels fall within the acceptable standard. However, the E. coli results were available after a time lag leading to beach closures from previous day results. Nowcast models allow beach managers to make real-time beach advisory decisions instead of waiting a day or more for laboratory results to become available.</p> <p>Using the historical data, an extensive experiment was carried out, to obtain the suitable input variables and optimal neural network architecture. The best feed-forward neural network model was developed using Bayesian Regularization Neural Network (BRNN) training algorithm. Developed ANN model showed an average prediction accuracy of around 87% in predicting the E. coli classes. </p>
23

Complex Vehicle Modeling: A Data Driven Approach

Alexander Christopher Schoen (8068376) 31 January 2022 (has links)
<div> This thesis proposes an artificial neural network (NN) model to predict fuel consumption in heavy vehicles. The model uses predictors derived from vehicle speed, mass, and road grade. These variables are readily available from telematics devices that are becoming an integral part of connected vehicles. The model predictors are aggregated over a fixed distance traveled (i.e., window) instead of fixed time interval. It was found that 1km windows is most appropriate for the vocations studied in this thesis. Two vocations were studied, refuse and delivery trucks.</div><div><br></div><div> The proposed NN model was compared to two traditional models. The first is a parametric model similar to one found in the literature. The second is a linear regression model that uses the same features developed for the NN model.</div><div><br></div><div> The confidence level of the models using these three methods were calculated in order to evaluate the models variances. It was found that the NN models produce lower point-wise error. However, the stability of the models are not as high as regression models. In order to improve the variance of the NN models, an ensemble based on the average of 5-fold models was created. </div><div><br></div><div> Finally, the confidence level of each model is analyzed in order to understand how much error is expected from each model. The mean training error was used to correct the ensemble predictions for five K-Fold models. The ensemble K-fold model predictions are more reliable than the single NN and has lower confidence interval than both the parametric and regression models.</div>

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