Machine Learning

Introduction

  • Machine Learning (ML): A subset of AI where algorithms learn from and make predictions on data.

  • Model: In ML, a model is a representation of an algorithm's learned patterns from data. It's what you use to make predictions on new data.

  • Deep Learning: A subset of ML using neural networks with many layers. It's more complex and requires more data.

  • Neural Networks in ML: Traditional machine learning can utilize simpler neural networks, but not all ML algorithms are based on them.

  • Codeability: Machine learning is "codeable", involving algorithms that learn from data. Libraries simplify this process.

Steps to Create a Machine Learning Algorithm

  1. Data Collection: Gather data relevant to your problem.

  2. Data Preprocessing: Clean and transform data to a usable format.

  3. Feature Engineering: Select or create the most relevant input features.

  4. Model Selection: Choose an appropriate algorithm based on the problem.

  5. Training: Feed the training data to the model to learn patterns.

  6. Evaluation: Test the model's performance on the validation set.

  7. Tuning: Adjust parameters to optimize performance.

  8. Deployment: Implement the model in a real-world application.

Common Algorithms & Their Uses

  • Linear Regression: Predict continuous values.

  • Logistic Regression: Classify data into two categories.

  • Decision Trees: Make decisions based on questions.

  • Random Forest: Uses multiple decision trees for better accuracy.

  • K-Means Clustering: Group data into 'k' clusters.

  • Support Vector Machines (SVM): Classify data by finding the best boundary.

  • Simple Neural Networks: Used in some ML tasks; less deep than deep learning networks.

Ensemble Methods

Using Multiple Algorithms: Yes, you can combine multiple algorithms to improve predictive performance. This is known as ensemble learning.

  • Bagging: Uses multiple instances of the same algorithm on different subsets of data.

  • Boosting: Sequentially applies algorithms, where each one corrects the errors of its predecessor.

  • Stacking: Combines predictions from multiple algorithms to make a final prediction.

Evaluation Metrics

  • Accuracy: How often the model is correct.

  • Precision & Recall: Balance between correctly predicted positives and actual positives.

  • F1 Score: Combines precision and recall.

  • Mean Absolute Error (MAE): Average error in regression tasks.

Overfitting & Underfitting

  • Bias-Variance Tradeoff: Balance between simplicity (bias) and complexity (variance).

  • Regularization: Add penalty to complex models to prevent overfitting.

Tools & Libraries

  • Languages: Python and R are popular for ML.

  • Scikit-learn: Comprehensive Python library for ML.

  • Pandas: Python library for data manipulation.

  • NumPy: Python library for numerical operations.

Tips

  • Always visualize your data.

  • Start simple and then explore complexity.

  • Update your model with new data when possible.

Last updated