Theodore B. Trafalis

Prof. Theodore B. Trafalis

School of Industrial and Systems Engineering, The University of Oklahoma, Norman, OK 73019, USA
orcid

Research Focus & Metrics

Academic Career Length

32Years (1995-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2000
Verified
Conference Paper
Closed access
TTTheodore B. Trafalis
Theodore B. Trafalis
HIH. Ince
H. Ince
The main purpose of the paper is to compare the support vector machine (SVM) developed by Cortes and Vapnik (1995) with other techniques such as backpropagation and radial basis function (RBF) networks for financial forecasting applications. The theory of the SVM algorithm is based on statistical learning theory. Training of SVMs leads to a quadratic programming (QP) problem. Preliminary computational results for stock price prediction are also presented.

16 September 2020 in Symmetry
Verified
Journal Article
Open access
PDF file
MAMd Manjurul Ahsan
Md Manjurul Ahsan
TATasfiq Alam
Tasfiq Alam
TTTheodore B. Trafalis
Theodore B. Trafalis
PHPedro Huebner
Pedro Huebner
The limitations and high false-negative rates (30%) of COVID-19 test kits have been a prominent challenge during the 2020 coronavirus pandemic. Manufacturing those kits and performing the tests require extensive resources and time. Recent studies show that radiological images like chest X-rays can offer a more efficient solution and faster initial screening of COVID-19 patients. In this study, we develop a COVID-19 diagnosis model using Multilayer Perceptron and Convolutional Neural Network (MLP-CNN) for mixed-data (numerical/categorical and image data). The model predicts and differentiates between COVID-19 and non-COVID-19 patients, such that early diagnosis of the virus can be initiated, leading to timely isolation and treatments to stop further spread of the disease. We also explore the benefits of using numerical/categorical data in association with chest X-ray images for screening COVID-19 patients considering both balanced and imbalanced datasets. Three different optimization algorithms are used and tested:adaptive learning rate optimization algorithm (Adam), stochastic gradient descent (Sgd), and root mean square propagation (Rmsprop). Preliminary computational results show that, on a balanced dataset, a model trained with Adam can distinguish between COVID-19 and non-COVID-19 patients with a higher accuracy of 96.3%. On the imbalanced dataset, the model trained with Rmsprop outperformed all other models by achieving an accuracy of 95.38%. Additionally, our proposed model outperformed selected existing deep learning models (considering only chest X-ray or CT scan images) by producing an overall average accuracy of 94.6% ± 3.42%.

1 January 2011 in Computational Statistics & Data Analysis
Verified
Journal Article
Closed access
MMMaher Maalouf
Maher Maalouf
TTTheodore B. Trafalis
Theodore B. Trafalis

1 September 2006 in European Journal of Operational Research
Verified
Journal Article
Closed access
TTTheodore B. Trafalis
Theodore B. Trafalis
RGRobin C. Gilbert
Robin C. Gilbert

1 November 2006 in Decision Support Systems
Verified
Journal Article
Closed access
HIHuseyin Ince
Huseyin Ince
TTTheodore B. Trafalis
Theodore B. Trafalis

3 November 2008 in International Journal of General Systems
Verified
Journal Article
Closed access
HIHuseyin Ince
Huseyin Ince
TTTheodore B. Trafalis
Theodore B. Trafalis
Forecasting a stock price movement is one of the most difficult problems in finance. The reason is that financial time series are complex, non stationary. Furthermore, it is also very difficult to predict this movement with parametric models. Instead of parametric models, we propose two techniques, which are data driven and non parametric. Based on the idea that excess returns would be possible with publicly available information, we developed two models in order to forecast the short term price movements by using technical indicators. Our assumption is that the future value of a stock price depends on the financial indicators although there is no parametric model to explain this relationship. This relationship comes from the technical analysis. Comparison shows that support vector regression (SVR) out performs the multi layer perceptron (MLP) networks for a short term prediction in terms of the mean square error. If the risk premium is used as a comparison criterion, then the SVR technique is as good as the MLP method or better.