Date of Submission
Fall 12-16-2020
Degree Type
Thesis
Degree Name
Master of Science in Computer Science (MSCS)
Department
Computer Science
Committee Chair/First Advisor
Dr. Dan lo
Track
Big Data
Chair
Dr. Dan Lo
Committee Member
Dr. Yong Shi
Committee Member
Dr. Hossain Shahriar
Abstract
Imbalanced datasets have been a unique challenge for machine learning, requiring specialized approaches to correctly classify the minority class. Financial fraud detection involves using highly imbalanced datasets with a class imbalance of up to .01% frauds to 99.99% regular transactions. It is essential to identify all frauds in financial fraud detection, even if some classifications' precision is low. I developed a random forest assembly that separates fraudulent transactions into tiers of precision. With this approach, 96% of fraudulent transactions are identified, showing an 8% increase in recall when compared to standard approaches. 59% of fraud classifications' precision increases by 10% up to 98% by optimizing several random forests on different fitness functions. These models are then combined to act as a sieve with increasing tolerance for low precision classifications. The effectiveness of random forest for financial fraud detection is also improved through feature extraction techniques. Random forest is weak at detecting patterns between interdepended features. This problem is address through unsupervised feature extraction. I will demonstrate a new random forest architecture PCA-embedded random forest, which increased random forest performance.