Machine Learning 101: A Comprehensive Guide for Beginners
Tags: machinelearning, datascience, ai, aws
Published: 2023-01-23 16:07:18

Machine learning is a method of teaching computers to learn from data, without being explicitly programmed. It is a subset of artificial intelligence that focuses on the development of algorithms and statistical models that can enable machines to improve their performance on a specific task by learning from data.

**Application:**
In the real world, machine learning is used in a wide range of applications. Some examples include:

- Self-driving cars, which use supervised learning to learn how to drive safely and efficiently.
- Image and speech recognition, which use supervised learning to identify objects and transcribe speech.
- Fraud detection, which uses supervised learning to identify suspicious transactions.
- Recommendation systems, which use unsupervised learning to suggest products or content to users.
- Robotics, which use reinforcement learning to train robots to perform tasks such as grasping objects or walking.

##How Machine Learning Works
The process of machine learning typically involves the following steps:

**1 - Collecting and preparing the data:** This step involves acquiring the data, cleaning it, and transforming it into a format that can be used by the machine learning algorithm.

**2 - Choosing a model:** This step involves selecting a machine learning algorithm that is appropriate for the task at hand.

**3 - Training the model:** This step involves using the labeled data to train the model, so that it can make accurate predictions on new data.

**4 - Evaluating the model:** This step involves using a separate dataset to evaluate the model's performance, and making adjustments as needed.

**5 - Deploying the model:** This step involves using the trained model to make predictions on new data, or using it to control a system in the real world.

---

##Main Types of Machine Learning


###1. Supervised
Supervised learning is a type of machine learning where the computer is given a labeled dataset, and the goal is to train a model to make predictions on new, unseen data. The model learns to make predictions about unseen data by finding patterns in the training data. 

**Example:**
One of the most common application of supervised machine learning model is to classify the different types of objects. For Example, in the figure below, we can see that there are some labeled data of square, triangle and hexagon and supervised machine learning model will tell us whether a new object will be square or triangle or hexagon based on its learning with the dataset.

![Himanshu Singh @ Medium](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/bi6a2afb2xreovoym911.png)

Some other examples of supervised learning tasks include:

- Image classification
- Spam detection
- Predicting stock prices
- Predict whether a person is likely to develop a certain medical condition based on their age, sex, and other factors

**Supervised Machine Learning Models:**

There are several types of models used in supervised machine learning, including:

**Linear Regression:** Linear regression is a statistical model that is used for predicting a continuous value. It works by finding the best-fitting line through the data points. Real-world examples include: Sales forecasting, Inventory prediction

**Logistic Regression:** Logistic regression is a statistical model that is used for binary classification tasks, such as determining if an email is spam or not. Real-world examples include: Medical diagnosis, Credit scoring

**Decision Trees:** A decision tree is a tree-like model that makes decisions based on a series of conditions. It is commonly used for classification and regression tasks. Real-world examples include: Credit scoring, Medical diagnosis

**Random Forest:** A random forest is an ensemble of decision trees, where each tree is trained on a different subset of the data. The final output is the average of the outputs of all the decision trees. Random forest is commonly used for classification and regression tasks. Real-world examples include: Stock market analysis, Quality control

**Support Vector Machines (SVMs):** SVMs are a type of model that can be used for both classification and regression tasks. They work by finding a line (or hyperplane) that maximally separates the different classes in the data. Real-world examples include: Handwriting recognition, Gene expression classification

**Neural Networks:** Neural networks are a type of model that are inspired by the structure and function of the human brain. They are commonly used for image and speech recognition, natural language processing, and other complex tasks. Real-world examples include: Image recognition, Speech recognition, Natural Language Processing

> **Summary:** In supervised machine learning, different models have different use cases and are good at different types of problems. It is important to understand the characteristics and assumptions of each model and choose the appropriate one for the specific problem at hand.

---


###2. Unsupervised
Unsupervised learning is a type of machine learning where the model is not provided with labeled data, and the goal is to find patterns or relationships in the input data by its own. It is used to discover hidden structure or features in data.


**Example:**
In fruit detection model, we didn't give any label to any of the food to the model. But the model check the characteristics and similarity of the object in dataset and based on that similarity it distinguish the dataset into two parts as shown in the figure. If a new fruit is given to the machine learning model, it will not tell it is apple or orange rather it put that object in one of the category.

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/occjg3piggeqdrxdds0i.png)

Some other examples of unsupervised learning tasks include:

- Clustering satellite images to identify distinct features in landscapes
- Anomaly detection in manufacturing process to identify faulty equipment
- Identifying patterns in genetic data for disease diagnosis
- Grouping customers by purchase history for targeted marketing
- Identifying patterns in network traffic for cybersecurity


**Unsupervised Machine Learning Models:**
There are several types of models used in unsupervised machine learning, including:

**K-Means:** K-means is a clustering algorithm that groups similar data points together. It is used for tasks such as market segmentation and image segmentation. Real-world examples include: Customer segmentation, Image segmentation

**Hierarchical Clustering:** Hierarchical Clustering is a method of clustering which builds a hierarchy of clusters. It is used for tasks such as image segmentation and gene expression analysis. Real-world examples include: Image segmentation, Gene expression analysis

**Principal Component Analysis (PCA):** PCA is a technique used for dimensionality reduction. It works by finding the principal components of the data, which are the directions of maximum variance. Real-world examples include: Face recognition, Handwriting recognition

**Autoencoder:** Autoencoder is a neural network used for dimensionality reduction and feature learning. It works by learning a compressed representation of the input data. Real-world examples include: anomaly detection, speech recognition

**Self-Organizing Maps (SOMs):** SOMs are a type of neural network that is used for visualization and dimensionality reduction. It projects high-dimensional data onto a 2-dimensional grid, preserving the topological structure of the data. Real-world examples include: Fraud detection, Quality control

**Generative Adversarial Networks (GANs):** GANs are a type of model composed of two neural networks: a generator and a discriminator. The generator creates new data samples that are similar to the training data, while the discriminator attempts to distinguish the generated data from the real data. Real-world examples include: Image synthesis, Text-to-speech


> **Summary:**
> Unsupervised machine learning models are good at finding hidden structure and patterns in data, and can be used in a wide range of applications. But it's important to understand the assumptions and limitations of each algorithm and choose the appropriate one for the specific problem at hand.

---


###3.Reinforcement
Reinforcement learning is a type of machine learning where the computer learns through trial and error. The goal is to train an agent to make decisions that will maximize a reward signal. For example, a reinforcement learning algorithm could be used to train a robot to navigate a maze by receiving a reward for reaching the end and a penalty for hitting a wall.


Some examples of reinforcement learning tasks include:

- Training autonomous vehicles to navigate in complex environments
- Improving energy efficiency in data centers
- Training robots to perform tasks such as grasping objects or walking
- Improving the performance of recommendation systems


**Reinforcement Machine Learning Models:**

There are several types of models used in reinforcement learning, including:

**Q-Learning:** Q-learning is a model-free algorithm that learns the optimal policy by estimating the value of each state-action pair. It's used for tasks such as game playing and robotics. Real-world examples include: Game playing, Robotics

**SARSA:** SARSA is a model-free algorithm that learns the optimal policy by estimating the value of each state-action pair. It's used for tasks such as game playing and robotics. Real-world examples include: Game playing, Robotics

**Policy Gradient Methods:** Policy gradient methods are a class of algorithms that optimize the policy directly, by gradient descent. It's used for tasks such as robotics and game playing. Real-world examples include: Robotics, Game playing

**Deep Deterministic Policy Gradient (DDPG):** DDPG is a variant of policy gradient methods that use a deep neural network as a function approximator. It's used for tasks such as robotics and game playing. Real-world examples include: Robotics, Game playing

**Proximal Policy Optimization (PPO):** PPO is an optimization algorithm that uses a trust region update to improve the policy. It's used for tasks such as robotics and game playing. Real-world examples include: Robotics, Game playing

> **Summary:**
> Reinforcement learning has been used to train agents to play games at a superhuman level, to control robots to perform complex tasks, and to drive cars in simulated environments. But it's important to understand that the success of RL depends on the quality of the reward function, which can be difficult to design.


_Machine learning is a rapidly growing field with many potential applications, and it has the potential to revolutionize many industries. With the increasing amount of data being generated, machine learning has the ability to analyze, understand and make predictions that can have significant impact in many areas such as healthcare, finance, education, transportation and many more. The future of machine learning is bright and it is expected to continue to evolve and play an increasingly important role in shaping the way we live and work._

---
Follow Me For More Such Content | [My Social Links](https://linktr.ee/abdulraheem01)