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shangkyu shin
shangkyu shin

Posted on • Originally published at zeromathai.com

Foundations of AI and Deep Learning: From Symbolic AI to Representation Learning Systems

Artificial Intelligence, Machine Learning, and Deep Learning are often used interchangeably—but they represent different layers of the same system.

Cross-posted from Zeromath. Original article: https://zeromathai.com/en/dl-foundations-of-ai-en/


Why This Matters

If you jump straight into deep learning without understanding the foundation:

  • concepts feel disconnected
  • models feel like black boxes
  • debugging becomes difficult

This post builds a structured view of AI from the ground up.


1. What is AI?

AI is about building systems that can:

  • think
  • learn
  • reason
  • make decisions

Early AI focused on rule-based systems (symbolic AI).

But real-world complexity forced a shift toward:

👉 learning from data


2. AI vs ML vs DL (Simple View)

  • AI → the goal (intelligence)
  • ML → learning from data
  • DL → deep neural networks

👉 Think of it as a hierarchy.


3. Three Waves of Deep Learning

Wave 1: Perceptron

  • simple neural model
  • limited (can’t solve XOR)

Wave 2: Backpropagation

  • multilayer networks
  • gradient-based learning

Wave 3: Modern DL

  • GPUs + big data
  • real-world applications

4. Machine Learning Basics

ML systems:

  • learn from data
  • improve over time
  • generalize to new inputs

5. Types of ML Problems

  • classification → categories
  • regression → continuous values
  • clustering → hidden structure
  • dimensionality reduction → compression
  • reinforcement learning → decision sequences

6. Generalization (The Real Goal)

Training performance is not enough.

👉 What matters:
performance on unseen data


7. Overfitting and Model Complexity

  • simple model → underfitting
  • complex model → overfitting

Solution:
👉 balance (bias-variance tradeoff)


8. Linear Models (Still Important)

  • linear regression
  • logistic regression

Why use them?

  • fast
  • interpretable
  • strong baseline

9. Neural Networks

Neural networks extend linear models.

Key idea:
👉 layers learn representations

Each layer extracts more abstract features.


10. Why Deep Learning Works

Two main reasons:

  • expressive models (can represent complex functions)
  • optimization (gradient descent)

Final Takeaway

AI is not one thing.

It’s a stack:

AI → ML → DL

Understanding this structure makes everything else easier.


Discussion

Where did you struggle the most when learning AI?

  • theory?
  • math?
  • implementation?

Let’s talk 👇

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