AI 101 - 2025 Class Recordings-Recording Workshop 4

Video Transcription

Video Summary

The video covers an advanced lesson on neural networks, starting with a review of basic machine learning concepts like confusion matrices, accuracy, and mean squared error calculations for regression problems. The instructor explains how to compute predicted values using a best-fit line and calculate errors by subtracting predicted from actual values, squaring the differences, and averaging them. The lesson then shifts to neural networks, introducing fundamental vocabulary such as neurons, layers (input, hidden, output), weights, and biases. <br /><br />Students learn that neural networks model complex nonlinear relationships and can be applied to tasks like speech recognition, natural language processing, financial forecasting, and medical diagnosis. The instructor details how to compute node outputs by multiplying inputs by weights, adding biases, and applying activation functions like ReLU. <br /><br />The concept of loss functions, especially hinge loss for classification, is explained as a way to measure prediction accuracy. The training process involves adjusting weights and biases through backpropagation to minimize loss. Practical exercises are provided to apply these calculations, and the session concludes with an overview of pros and cons of neural networks, including their adaptability, data demands, computational expense, and risk of overfitting. The homework involves working through calculations of neural network outputs and loss functions, reinforcing the lesson’s concepts.

Keywords

neural networks

machine learning

confusion matrix

mean squared error

regression

neurons

activation functions

backpropagation

loss functions