Machine Learning 101: Algorithms, Models, and Training

Machine Learning 101: Algorithms, Models, and Training

Machine learning is one of the subsets of artificial intelligence. It focuses on creating algorithms and models that let computers learn and make decisions or projections based on available data. It is a quickly growing space with multiple applications in many domains, including natural language processing (NLP), image recognition, recommendation systems, and a lot more. 

Here are the fundamental concepts of machine learning:


Machine learning algorithms are the primary components of the machine learning process. They are the mathematical and computational techniques that let computers learn from data and make various predictions. Different types of machine learning algorithms exist. However, they can be categorized into three major groups.

Supervised Learning 

In supervised learning, algorithms learn directly from a labeled dataset, where every data point is linked to a target or outcome. The algorithm aims to learn a mapping from input data to the correct output, which makes it suitable for tasks such as regression and classification.

Unsupervised Learning

Unsupervised learning algorithms work with unlabeled data, striving to discover various patterns, relationships, and structures within the data. Some of the usual tasks involved include clustering (grouping all similar data points) and dimensionality reduction.

Reinforcement Learning

Reinforcement learning consists of training an agent to interact with an environment and learn by getting feedback in the form of penalties or rewards. The agent’s key objective is to enhance its cumulative reward, making it highly suitable for applications such as robotic control and game-playing.


In machine learning, a model is a representation of the learned patterns and relationships that exist within the data. Models are designed using algorithms and are the tools that make projections or decisions according to new and unseen data. Some usual types of machine learning models include:

Linear Regression

A simple model is used for regression tasks, where the aim is to forecast an uninterrupted numeric value. It assumes a linear relationship between the input features and the target variable.

Logistic Regression

Similar to linear regression but it is used for binary classification tasks. It models the possibility of an instance that belongs to one of two classes.

Decision Trees

Tree-like structures that make various decisions by splitting data based on the values of input features. They are utilized for regression and classification tasks.

Neural Networks

Complex models inspired by the structure of the human brain. Deep learning, or deep neural networks, have been specifically successful in different tasks, including image and speech recognition.


The training process of a machine learning model involves feeding it a labeled dataset, which features input data and corresponding target values. This model learns from the data by adjusting its internal parameters to limit the error between its projections and the real targets. The main steps in training a machine learning model include:

Data Preparation

This step involves collecting, cleaning, and preprocessing the data. It may consist of tasks such as feature engineering, data normalization, and data splitting into training and testing sets.

Data Preprocessing

The machine learning lifecycle features data preprocessing and at this stage, data quality works as the focal point that guides machine learning operations toward success. The foundation of any AI model lies in data collection and preprocessing. 

Quality data acquired at this stage boosts the reliability of the analyses and model training steps that follow. Guaranteeing that the collected data is clean, consistent, and representative reduces the risk of skewed or misleading results.

Model Selection

Select an appropriate algorithm and model infrastructure for the particular task. The choice of model significantly depends on the nature of the problem, for example, classification and regression, and the characteristics of the data.

Loss Function 

The choice of a loss function is influenced by the task. For regression, mean squared error (MSE) is often used. On the other hand, cross-entropy loss is commonly used for classification.


Gradient-based optimization strategies such as stochastic gradient descent (SGD) are used in updating model parameters iteratively. Learning rates and optimizers such as Adam or RMSprop are selected based on the issue.

Training Loop

In every iteration (epoch), the model makes projections on the training data, calculates all losses, and updates its parameters to mitigate the loss.


After training, the model’s performance is evaluated using a distinct test dataset to evaluate its generalization capabilities. Common evaluation metrics include precision, accuracy, and mean squared error, subject to the task.

Training the Model

During training, the model iteratively adjusts its internal parameters using optimization techniques, such as gradient descent, to minimize the prediction error. The process continues until the model reaches a satisfactory performance level. 


After a model is trained and validated, it can be deployed in real-world applications to make forecasts or decisions on new, unseen data.

Issues That Can Affect Machine Learning Models

Many issues can interfere with and affect the results of a machine learning model’s operations. These issues range from problems with the data itself to poor decisions and choices on the part of the developers.

In case the machine learning model tries to draw from a data set that has faulty or poor-quality data, the results end up skewed and unreliable. On the same note, if data is inadequate to power the process, the results are eventually unsatisfactory. Also, if there is an inherent bias in the data set that was not identified, the machine learning results highlight and magnify the biases, resulting in the creation of faulty results.

Furthermore, it depends on the machine learning developers to select the correct algorithm to approach every data set. The wrong choice can result in inefficient or messy processing. Developers need to be wary of underfitting and overfitting, which may dilute and invalidate the machine learning performance, delivering inaccurate results with too much bias or too much variance.

Developers also need to select the best hyperparameters to fit with the given data set. Poor hyperparameter tuning is a possible challenge that may have detrimental impacts on a machine learning model.


In general, machine learning consists of using algorithms to train models that can make decisions or predictions based on data. The choice of model, algorithm, and training process depends on the particular problem and dataset. Machine learning has a wide range of specific applications and is constantly evolving as new techniques and algorithms are developed. 

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