Neural Networks 101: Understanding the Basics

Learn the fundamentals of neural networks and their significance in machine learning

Mohit Mishra
Nerd For Tech
6 min readFeb 3, 2024

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Hello, everyone. I hope you are doing well. This is the first part of my Neural Networks 101 series, in this blog we are going to understand the basics.

Let’s start by understanding what neural networks are and diving into the basics of them with practical applications and key components for neural networks.

Neural networks (NNs) are a fundamental concept in machine learning that draws inspiration from the human brain’s structure and function. They are made up of interconnected layers of nodes, also known as neurons, that process and transform input data before producing an output. Each connection between nodes is assigned a weight, and each node typically applies an activation function to the weighted sum of its inputs.

Neural networks are important in machine learning because they can learn complex patterns and relationships in data, making them effective tools for classification, regression, and pattern recognition.

Basic Architecture

  • Input Layer: This layer accepts input data, which may include features extracted from images, text, or other sources.
  • Hidden Layers: These intermediate layers transform the input data using a series of mathematical operations. Each layer extracts increasingly abstract features from its input.
  • Output Layer: This layer generates the neural network’s final output, which may be a classification label, a predicted value, or another type of output.
Source: Image by the author.

Comparison to Traditional Algorithms

Neural networks differ from traditional algorithms in several major ways:

  • Flexibility: Neural networks can learn complex patterns and relationships in data without having to explicitly program rules.
  • Non-linearity: Because neural networks can capture non-linear relationships in data, they are ideal for tasks that traditional linear algorithms may struggle with.
  • Scalability: Neural networks can handle large datasets and complex problems, whereas traditional algorithms may become computationally inefficient

Voice assistants use neural networks to interpret and respond to user commands and queries. When you speak to a voice assistant, your words are converted into digital signals and processed by a neural network model. This model processes speech data to extract meaning, identify keywords, and determine the user’s intent.

  • The voice input is converted to a digital signal and preprocessed to extract relevant features like pitch, tone, and phonemes.
  • The neural network’s intermediate layers process the extracted features to identify patterns and context in the speech data.
  • The final layer of the neural network generates the output, which could be a response to the user’s query or an action, such as setting

Why Neural Networks Matter in Machine Learning

Neural networks are important in machine learning because of their versatility and effectiveness across a wide range of applications. Here is why they matter:

  • Neural networks can accurately classify objects within images, making them useful for applications such as facial recognition, self-driving cars, and medical image analysis.
  • Neural networks excel at natural language processing tasks like sentiment analysis, language translation, and speech recognition, which power virtual assistants and chatbots.
  • Neural networks are used in finance to detect fraud, assess risk, and perform algorithmic trading by leveraging their ability to analyze complex financial data.

Real-World Applications

The ability of neural networks to solve complex problems has revolutionized a variety of industries. Some real-world applications are:

  • Healthcare: Neural networks help diagnose diseases using medical images, predict patient outcomes, and discover new drug compounds.
  • Finance: Neural networks can improve investment strategies, detect fraudulent transactions, and forecast market trends.
  • Retailers use neural networks to personalize recommendations, optimize supply chain logistics, and analyze customer sentiment based on reviews and social media data.

Handling Complex, Unstructured Data

One of the neural networks’ main advantages is their ability to handle complex and unstructured data effectively. Unlike traditional algorithms that rely on manually created features, neural networks can learn relevant features from raw data. This makes them well-suited for tasks that require:

  • Images: Neural networks can extract useful features from pixel data, allowing for accurate image classification and object detection.
  • Text: Neural networks can understand the semantic meaning of text, allowing for tasks such as sentiment analysis, language translation, and text summarization.
  • Time Series Data: Neural networks can model temporal dependencies in data, making them useful for forecasting, anomaly detection, and sequence prediction.

Key Components of Neural Networks

Neural networks are made up of several key components that interact to process and analyze data. Understanding these components is critical for comprehending how neural networks operate. Here’s the breakdown:

Activation Functions

I’ve already published a detailed blog on activation functions, which I recommend everyone read because I can’t go into detail about the concept of activation functions in this blog; otherwise, this blog will be too long.

Please follow this link for a detailed blog on Activation Function.

Activation functions are mathematical functions that affect the outputs of neurons in a neural network. They introduce nonlinearity into the network, allowing it to learn complex patterns in the data. Common activation functions are:

  • Sigmoid: The sigmoid function reduces the output of each neuron to a value between 0 and 1, which can be interpreted as probability. It is frequently used for binary classification tasks.
  • The ReLU (Rectified Linear Unit) function returns the input value if it is positive; otherwise, it returns zero. ReLU has become the standard for most neural network architectures due to its simplicity and effectiveness.
  • TanH (Hyperbolic Tangent): The TanH function is similar to the sigmoid function, but it restricts the output to a range of -1 and 1. It is commonly used in neural network’s hidden layers.

Practical Applications of Activation Function

  • Experimenting with various activation functions is often required to determine which one works best for a given problem.
  • When selecting an activation function, consider network architecture, data distribution, and training dynamics.
  • Batch normalization and initialization strategies can help alleviate some of the difficulties associated with activation functions.

Sneak Peak

In a neural network, each neuron performs mathematical operations such as computing a weighted sum of inputs and applying an activation function. Let’s denote the inputs to a neuron as x1, x2, x3, …, xn,​ and the corresponding weights as w1, w2, w3, …, wn. The neuron’s output (y) is computed as follows:

Source: Image by the author.

Where f represents the activation function. Using this mathematical model, neural networks can learn complex mappings between inputs and outputs by adjusting weights during training.

The next part of this series will be primarily concerned with Neural Network Training and the components that contribute to it.

About Me

My name is Mohit Mishra, and I’m a blogger that creates intriguing content that leave readers wanting more. Anyone interested in machine learning and data science should check out my blog. My writing is designed to keep you engaged and intrigued with a regular publishing schedule of a new piece every two days. Follow along for in-depth information that will leave you wanting more!

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Mohit Mishra
Nerd For Tech

My skills include Data Analysis, Data Visualization, Machine learning, and Deep Learning. I have developed a strong acumen for problem-solving, and I enjoy ML.