2025-09-03

Introduction

Overview

3 types of ML

• Supervised learning
  • Classification
  • Regression
• Unsupervised learning
  • Clustering
    • Scatter plot
  • Dimensionality reduction 降维
• Reinforcement learning

Outline of the course

Basics

Data matrix

Feature vector

Histogram

Text as a vector

1. “It is sunny outside” =>[1 1 1 1 0 0 0 …]
2. “yesterday it was cloudy” =>[1 0 0 0 1(yes) 1 1 0]
3. “Is it nice, is it not?” =>[2 2 0 0 0 0 0 0 1 1 0]

tf-idf text representation

??

Neural network -based text representations

Summary