Spam Detection Model
Overview
This project implements a complete spam detection pipeline using multiple machine learning approaches, progressing from classical models to deep learning and finally to a compressed model using knowledge distillation.
The system performs multi-class classification, where each email is categorized into one of three classes:
- 0 → Ham (legitimate emails)
- 1 → Phish (fraudulent emails attempting to steal sensitive information)
- 2 → Spam (unsolicited or promotional messages)
It focuses on achieving high accuracy while also optimizing model size and efficiency for deployment.
Approaches Used
🔹 Classical Machine Learning
- Logistic Regression (TF-IDF with unigrams + bigrams)
- Support Vector Machine (Linear SVM with class balancing)
These models serve as strong baselines for text classification.
🔹 Neural Network (Teacher Model)
- Large-scale model (~80M parameters)
- Word embeddings (512 dimensions)
- Global max pooling over sequences
- Multiple residual blocks with normalization and dropout
This model achieves the highest performance and captures complex patterns in text.
🔹 Knowledge Distillation (Student Model)
Smaller model trained to mimic the teacher
Reduced vocabulary (~20k) and embedding size (128d)
Uses both:
- True labels (CrossEntropy)
- Teacher outputs (KL Divergence)
This allows significant model compression while maintaining high accuracy.
Key Techniques
- TF-IDF vectorization for classical models
- Tokenization with fixed sequence length (150 tokens)
- Class weighting to handle imbalance
- Residual connections for stable deep training
- Attention mechanism in student model for efficiency
- Temperature scaling and loss balancing in distillation
Performance Summary
| Model | Test Accuracy | Notes |
|---|---|---|
| Logistic Regression | ~95.3% | TF-IDF baseline |
| SVM | ~95.4% | Improved margin-based classifier |
| Neural Network (Teacher) | ~98.38% | High-capacity model |
| Distilled Model (Student) | ~98.12% | Lightweight + efficient |
Model Efficiency
| Model | Parameters | Purpose |
|---|---|---|
| Teacher | ~80M | Maximum accuracy |
| Student | ~2M | Fast + deployable |
The distilled model achieves near-teacher performance with a fraction of the size.