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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.
1

Application of Neural Networks to Inverter-Based Resources

Venkatachari, Sidhaarth 18 May 2021 (has links)
With the deployment of sensors in hardware equipment and advanced metering infrastructure, system operators have access to unprecedented amounts of data. Simultaneously, grid-connected power electronics technology has had a large impact on the way electrical energy is generated, transmitted, and delivered to consumers. Artificial intelligence and machine learning can help address the new power grid challenges with enhanced computational abilities and access to large amounts of data. This thesis discusses the fundamentals of neural networks and their applications in power systems such as load forecasting, power system stability analysis, and fault diagnosis. It extends application of neural networks to inverter-based resources by studying the implementation and performance of a neural network controller emulator for voltage-sourced converters. It delves into how neural networks could enhance cybersecurity of a component through multiple hardware and software implementations of the same component. This ensures that vulnerabilities inherent in one form of implementation do not affect the system as a whole. The thesis also proposes a comprehensive support vector classifier (SVC)--based submodule open-circuit fault detection and localization method for modular multilevel converters. This method eliminates the need for extra hardware. Its efficacy is discussed through simulation studies in PSCAD/EMTDC software. To ensure efficient usage of neural networks in power system simulation softwares, this thesis entails the step by step implementation of a neural network custom component in PSCAD/EMTDC. The custom component simplifies the process of recreating a neural network in PSCAD/EMTDC by eliminating the manual assembly of predefined library components such as summers, multipliers, comparators, and other miscellaneous blocks. / Master of Science / Data analytics and machine learning play an important role in the power grids of today, which are continuously evolving with the integration of renewable energy resources. It is expected that by 2030 most of the electric power generated will be processed by some form of power electronics, e.g., inverters, from the point of its generation. Machine learning has been applied to various fields of power systems such as load forecasting, stability analysis, and fault diagnosis. This work extends machine learning applications to inverter-based resources by using artificial neural networks to perform controller emulation for an inverter, provide cybersecurity through heterogeneity, and perform submodule fault detection in modular multilevel converters. The thesis also discusses the step by step implementation of a neural network custom component in PSCAD/EMTDC software. This custom component simplifies the process of creating a neural network in PSCAD/EMTDC by eliminating the manual assembly of predefined library components.
2

Predicting Risk Level in Life Insurance Application : Comparing Accuracy of Logistic Regression, DecisionTree, Random Forest and Linear Support VectorClassifiers

Karthik Reddy, Pulagam, Veerababu, Sutapalli January 2023 (has links)
Background: Over the last decade, there has been a significant rise in the life insurance industry. Every life insurance application is associated with some level ofrisk, which determines the premium they charge. The process of evaluating this levelof risk for a life insurance application is time-consuming. In the present scenario, it is hard for the insurance industry to process millions of life insurance applications.One potential approach is to involve machine learning to establish a framework forevaluating the level of risk associated with a life insurance application. Objectives: The aim of this thesis is to perform two comparison studies. The firststudy aims to compare the accuracy of the logistic regression classifier, decision tree classifier, random forest classifier and linear support vector classifier for evaluatingthe level of risk associated with a life insurance application. The second study aimsto identify the impact of changes in the dataset over the accuracy of these selected classification models. Methods: The chosen approach was an experimentation methodology to attain theaim of the thesis and address its research questions. The experimentation involvedcomparing four ML algorithms, namely the LRC, DTC, RFC and Linear SVC. These algorithms were trained, validated and tested on two datasets. A new dataset wascreated by replacing the "BMI" variable with the "Life Expectancy" variable. Thefour selected ML algorithms were compared based on their performance metrics,which included accuracy, precision, recall and f1-score. Results: Among the four selected machine learning algorithms, random forest classifier attained higher accuracy with 53.79% and 52.80% on unmodified and modifieddatasets respectively. Hence, it was the most accurate algorithm for predicting risklevel in life insurance application. The second best algorithm was decision tree classifier with 51.12% and 50.79% on unmodified and modified datasets. The selectedmodels attained higher accuracies when they are trained, validated and tested withunmodified dataset. Conclusions: The random forest classifier scored high accuracy among the fourselected algorithms on both unmodified dataset and modified datasets. The selected models attained higher accuracies when they are trained, validated and tested with unmodified compared to modified dataset. Therefore, the unmodified dataset is more suitable for predicting risk level in life insurance application.
3

Comparision of Machine Learning Algorithms on Identifying Autism Spectrum Disorder

Aravapalli, Naga Sai Gayathri, Palegar, Manoj Kumar January 2023 (has links)
Background: Autism Spectrum Disorder (ASD) is a complex neurodevelopmen-tal disorder that affects social communication, behavior, and cognitive development.Patients with autism have a variety of difficulties, such as sensory impairments, at-tention issues, learning disabilities, mental health issues like anxiety and depression,as well as motor and learning issues. The World Health Organization (WHO) es-timates that one in 100 children have ASD. Although ASD cannot be completelytreated, early identification of its symptoms might lessen its impact. Early identifi-cation of ASD can significantly improve the outcome of interventions and therapies.So, it is important to identify the disorder early. Machine learning algorithms canhelp in predicting ASD. In this thesis, Support Vector Machine (SVM) and RandomForest (RF) are the algorithms used to predict ASD. Objectives: The main objective of this thesis is to build and train the models usingmachine learning(ML) algorithms with the default parameters and with the hyper-parameter tuning and find out the most accurate model based on the comparison oftwo experiments to predict whether a person is suffering from ASD or not. Methods: Experimentation is the method chosen to answer the research questions.Experimentation helped in finding out the most accurate model to predict ASD. Ex-perimentation is followed by data preparation with splitting of data and by applyingfeature selection to the dataset. After the experimentation followed by two exper-iments, the models were trained to find the performance metrics with the defaultparameters, and the models were trained to find the performance with the hyper-parameter tuning. Based on the comparison, the most accurate model was appliedto predict ASD. Results: In this thesis, we have chosen two algorithms SVM and RF algorithms totrain the models. Upon experimentation and training of the models using algorithmswith hyperparameter tuning. SVM obtained the highest accuracy score and f1 scoresfor test data are 96% and 97% compared to other model RF which helps in predictingASD. Conclusions: The models were trained using two ML algorithms SVM and RF andconducted two experiments, in experiment-1 the models were trained using defaultparameters and obtained accuracy, f1 scores for the test data, and in experiment-2the models were trained using hyper-parameter tuning and obtained the performancemetrics such as accuracy and f1 score for the test data. By comparing the perfor-mance metrics, we came to the conclusion that SVM is the most accurate algorithmfor predicting ASD.

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