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Building a Fraud Detection Model: My Journey from EDA to Deployment on AWS

Dr Dilek Celik

Summary

  • Built and maintained Logistic Regression, Random Forest, and Deep Neural Network models.

  • Performed EDA, Statistical Analysis, Data Cleaning, and handled Missing Data and Outliers.

  • Conducted Feature Engineering and Data Pre-processing (train-test split, scaling, SMOTE).

  • Built models, applied Cross-Validation, and evaluated with confusion matrix and classification report.

  • Compared models, generated predictions, and deployed final model.

  • Deployed Logistic Regression model with 95% accuracy using Flask on AWS cloud.


Project Overview

In today’s digital landscape, fraud detection has become crucial across industries, especially in finance and e-commerce, where detecting fraudulent transactions in real time can save significant costs and protect consumers. This blog post details my fraud detection project, where I built and maintained several machine learning models to detect fraudulent activities effectively. Throughout this project, I implemented essential steps from data analysis to model deployment. Here’s an in-depth look at each stage.


The primary goal of this project was to design a robust fraud detection model using various machine learning techniques. I developed models, including Logistic Regression, Random Forest, and Deep Neural Networks, with a strong focus on ensuring high accuracy and real-time scalability. Ultimately, I deployed the top-performing model—a Logistic Regression model with 95% accuracy—using Flask on AWS cloud, enabling efficient real-time fraud detection. Below are the key steps I undertook to complete this project.

Step-by-Step Breakdown

  1. Building and Maintaining Models

    • Models Used: Logistic Regression, Random Forest, and Deep Neural Network.

    • These models were selected based on their diverse strengths in handling structured data and interpreting complex patterns, with each model contributing unique predictive insights.

  2. Exploratory Data Analysis (EDA)

    • Conducted an initial data exploration to understand the distribution, relationships, and key patterns within the data.

    • Visualized fraud cases versus non-fraud cases to gain insights into underlying fraud trends.

  3. Statistical Data Analysis

    • Used statistical analysis techniques to further examine data characteristics, correlations, and relationships that could enhance model accuracy.

    • This analysis also provided insights that informed feature engineering decisions.

  4. Data Cleaning

    • Identified and corrected inconsistencies, inaccuracies, and redundancies in the data.

    • Data cleaning helped ensure model reliability by reducing potential noise and errors within the dataset.

  5. Handling Missing Data

    • Applied strategies to address missing values effectively, either by imputing data or eliminating irrelevant entries.

    • Ensuring complete data was crucial for model performance and accuracy.

  6. Outliers Check

    • Analyzed the dataset for outliers that could skew the model, particularly in financial transaction data where fraud cases often involve abnormal values.

    • Adjusted for outliers to maintain data integrity and avoid biases in model predictions.

  7. Feature Engineering

    • Created new features based on domain knowledge and insights from EDA and statistical analysis to improve model interpretability and predictive power.

    • Engineered features contributed significantly to the model’s ability to accurately classify fraudulent versus non-fraudulent transactions.

  8. Data Pre-processing

    • Train-test Split: Divided the data into training and testing sets to validate the models effectively.

    • Scaling: Standardized data to bring features to a consistent scale, which is especially important for algorithms sensitive to feature magnitude.

    • SMOTE (Synthetic Minority Over-sampling Technique): Used SMOTE to handle class imbalance by generating synthetic samples for the minority (fraudulent) class, ensuring balanced data input for model training.

  9. Model Building

    • Trained the Logistic Regression, Random Forest, and Deep Neural Network models on the processed data.

    • Each model was carefully fine-tuned to maximize predictive performance and achieve a high level of accuracy.

  10. Cross-Validation

    • Performed cross-validation to assess the models’ performance across multiple subsets of data, ensuring stability and generalization to unseen data.

  11. Model Evaluation

    • Confusion Matrix: Analyzed the confusion matrix to understand classification results, including True Positives, False Positives, True Negatives, and False Negatives.

    • Classification Report: Generated a classification report to obtain metrics such as precision, recall, and F1 score, which offered deeper insights into model performance, particularly in detecting fraud cases.

  12. Model Comparison

    • Compared model performance based on evaluation metrics to identify the most accurate and reliable model for fraud detection.

    • The Logistic Regression model emerged as the top-performing model, achieving a 95% accuracy score.

  13. Making Predictions

    • Deployed the trained models to make predictions on new data, focusing on detecting potential fraud cases with high precision.

  14. Model Deployment

    • Deployed the Logistic Regression model using Flask and hosted it on AWS cloud.

    • With a 95% accuracy score, the model is optimized for real-time fraud detection, offering a scalable solution that supports timely decision-making.


Final Thoughts

This fraud detection project provided me with valuable insights and experience across the entire machine learning pipeline, from data exploration to model deployment. By building and refining Logistic Regression, Random Forest, and Deep Neural Network models, I could understand the strengths of each approach and ultimately deliver a solution optimized for real-world application.

Through deployment on AWS cloud, this project is a ready-to-use solution capable of flagging potential fraud cases in real time. I’m excited to continue refining my skills in AI and machine learning, especially in tackling industry challenges like fraud detection, where data-driven insights can have a significant impact on business security and user trust.

This project highlights how rigorous data analysis, thoughtful model selection, and strategic deployment can turn data into powerful insights, offering a robust foundation for ongoing learning and development in the AI and data science field. Thank you for joining me on this journey through the world of fraud detection!


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