Day 04 — Part 1: Intro to Deep Learning¶
Deep learning is the engine behind image recognition, language translation, and speech synthesis — but it is also one of the most misapplied tools in the field. Today you will build a mental model of how neural networks actually work, train one from scratch in Keras, and develop the practitioner instinct to know when deep learning is the right choice and when it is overkill.
Session Overview
Difficulty: Intermediate–Advanced Reading time: ~3 hours | Exercises: ~2 hours Prerequisites: Linear algebra (matrix multiplication) · Gradient descent concepts · Classification and regression fundamentals · NumPy vectorised operations
Learning Objectives¶
By the end of this session you will be able to:
- Explain what a neuron computes and why activation functions are essential
- Describe the forward pass, loss computation, and backpropagation in plain language
- Build, compile, train, and evaluate a neural network using Keras
- Diagnose overfitting from a training curve and apply at least two countermeasures
- Decide when deep learning is worth its added complexity vs. when gradient boosting is the better call
Session Map¶
| # | Topic | File | Estimated Time |
|---|---|---|---|
| 1 | Neural Network Intuition | 01-neural-network-intuition | 25 min |
| 2 | Training Neural Networks | 02-training-neural-networks | 30 min |
| 3 | Keras Quickstart | 03-keras-quickstart | 30 min |
| 4 | Overfitting and Regularization | 04-overfitting-regularization | 25 min |
| 5 | Exercises | 05-exercises | 45 min |
Total estimated time: ~2.5 hours
Prerequisites¶
Before this session, you should be comfortable with:
- Python functions and classes (Week 01)
- NumPy arrays and matrix operations (Week-01/Day-02-NumPy/01-numpy-arrays)
- The bias-variance tradeoff (Week-01/Day-06-Statistics/03-bias-variance)
- What a loss function is (from the ML evaluation day)
Info
This session uses TensorFlow 2.x with the Keras API. Install with pip install tensorflow. GPU is not required — all examples run on CPU in minutes.
Tip
Work through the files in order. The exercises in 05-exercises.md reference concepts from all four content files.
Start with 01-neural-network-intuition.