Module 1 — Machine Learning & Neural Network Basics

Published:

Deep Learning Tutorial Series

This module introduces the core ideas behind machine learning and neural networks. The focus is on intuition rather than mathematics or code.


1.1 Learning Goals

By the end of this module, you should understand:

  • What machine learning is
  • Difference between traditional programming and ML
  • Types of machine learning (supervised / unsupervised)
  • What a model is
  • Basic structure of a neural network
  • How predictions are generated

1.2 What is Machine Learning?

Machine learning is a way for computers to learn patterns from data instead of being explicitly programmed with rules.

Traditional programming

Rules + Data → Output

Machine learning

Data + Output → Learn Rules (Model)

In ML, the system learns a function that maps inputs to outputs.


1.3 Types of Machine Learning

1) Supervised Learning

  • Data includes inputs and correct answers (labels)
  • Example:

    • Image → cat / dog
    • Email → spam / not spam

Goal: learn mapping from input to output


2) Unsupervised Learning

  • Data has no labels
  • Example:

    • Clustering customers
    • Finding patterns in data

Goal: discover hidden structure in data


3) Reinforcement Learning (overview only)

  • Learning through rewards and feedback
  • Example: game agents learning to play

1.4 What is a Model?

A model is a function that learns from data:

y = f(x)

Where:

  • x = input
  • y = output prediction
  • f = learned mapping

Training means learning the best function f.


1.5 What is a Neural Network?

A neural network is a model made of layers of simple computational units called neurons.

Structure:

  • Input layer
  • Hidden layers
  • Output layer

Each layer transforms the data step by step.


1.6 The Neuron (Core Idea)

A neuron performs:

output = activation(w1*x1 + w2*x2 + ... + b)

Where:

  • x = inputs
  • w = weights (learned importance)
  • b = bias
  • activation = non-linear function

The neuron learns which inputs matter most.


1.7 Activation Functions

Without activation functions, a neural network would only be a linear model.

ReLU

f(x) = max(0, x)
  • Most commonly used
  • Simple and effective

Sigmoid

  • Outputs between 0 and 1
  • Often used for binary classification

Tanh

  • Outputs between -1 and 1
  • Less commonly used in modern deep learning

1.8 Forward Pass (Prediction Process)

A forward pass is how a neural network makes predictions:

Input → Layers → Output

Steps:

  1. Input enters network
  2. Each layer applies weights + activation
  3. Final layer produces prediction

1.9 Simple Example

Predicting house price:

Inputs:

  • Size
  • Location
  • Number of rooms

Output:

  • Price

The model learns how each feature affects the final price.


1.10 What Does “Learning” Mean?

Learning means improving predictions by adjusting weights.

High-level process:

  1. Make prediction
  2. Compare with correct answer
  3. Measure error
  4. Adjust parameters

(Training details will come in Module 2)


1.11 Key Terms Summary

TermMeaning
ModelFunction that maps input to output
FeatureInput variable
LabelCorrect output
TrainingLearning from data
PredictionModel output

1.12 Quick Check (No Coding)

Think about:

  • What inputs would a weather prediction model need?
  • What is the output?
  • Is this supervised or unsupervised learning?

Acknowledgement

Part of the contents are generated by ChatGPT.

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