1️⃣ **Introduction to Neural Networks (One Hidden Layer)** πŸ€– - A neural network is like a **thinking machine** that makes decisions. - It **learns from data** and gets better over time. - We build a network with **one hidden layer** to help it **think smarter**. 2️⃣ **More Neurons, Better Learning!** 🧠 - If a network **isn’t smart enough**, we add **more neurons**! - More neurons = **better decision-making**. - We train the network to **recognize patterns more accurately**. 3️⃣ **Neural Networks with Multiple Inputs** πŸ”’ - Instead of just **one piece of data**, we give the network **many inputs**. - This helps it **understand more complex problems**. - Too many neurons = **overfitting (too specific)**, too few = **underfitting (too simple)**. 4️⃣ **Multi-Class Neural Networks** 🎨 - Instead of choosing between **two options**, the network can choose **many!** - It learns to **classify things into multiple groups**, like recognizing **different animals**. - The Softmax function helps it **pick the best answer**. 5️⃣ **Backpropagation: Learning from Mistakes** πŸ”„ - The network **makes a guess**, checks if it’s right, and **fixes itself**. - It does this using **backpropagation**, which adjusts the neurons. - This is how AI **gets smarter with time**! 6️⃣ **Activation Functions: Helping AI Decide** ⚑ - Activation functions **control how neurons react**. - Three common types: - **Sigmoid** β†’ Good for probabilities. - **Tanh** β†’ Helps balance data. - **ReLU** β†’ Fastest and most useful! - These functions help the network **learn efficiently**. # πŸ“– AI Terms and Definitions (Based on the Videos) πŸ€– ### 🧠 **Neural Network** A **computer brain** that learns by adjusting numbers (weights) to make decisions. ### 🎯 **Classification** Teaching AI to **sort things into groups**, like recognizing cats 🐱 and dogs 🐢 in pictures. ### ⚑ **Activation Function** A rule that helps AI **decide which information is important**. Examples: - **Sigmoid** β†’ Soft decision-making. - **Tanh** β†’ Balances positive and negative values. - **ReLU** β†’ Fast and effective! ### πŸ”„ **Backpropagation** AI’s way of **fixing mistakes** by looking at errors and adjusting itself. ### πŸ“‰ **Loss Function** A **score** that tells AI **how wrong** it was, so it can improve. ### πŸš€ **Gradient Descent** A method that helps AI **learn step by step** by making small changes to improve. ### πŸ—οΈ **Hidden Layer** A **middle part of a neural network** that helps process complex information. ### πŸŒ€ **Softmax Function** Helps AI **choose the best answer** when there are multiple choices. ### βš–οΈ **Cross Entropy Loss** A way to measure **how well AI is learning** when making choices. ### πŸ“Š **Multi-Class Neural Networks** AI models that can **choose from many options**, not just two. ### 🏎️ **Momentum** A trick that helps AI **learn faster** by keeping track of past updates. ### πŸ” **Overfitting** When AI **memorizes too much** and struggles with new data. ### πŸ˜• **Underfitting** When AI **doesn’t learn enough** and makes bad predictions. ### 🎨 **Convolutional Neural Network (CNN)** A special AI for **understanding images**, used in things like face recognition. ### πŸ“¦ **Batch Processing** Instead of training on **one piece of data at a time**, AI looks at **many pieces at once** to learn faster. ### πŸ—οΈ **PyTorch** A tool that helps build and train neural networks easily.