Introduction to Neural Network in Machine Learning

VARIN ANAND 28 Mar, 2024 • 9 min read

Neural network is the fusion of artificial intelligence and brain-inspired design that reshapes modern computing. With intricate layers of interconnected artificial neurons, these networks emulate the intricate workings of the human brain, enabling remarkable feats in machine learning. There are different types of neural networks, from feedforward to recurrent and convolutional, each tailored for specific tasks. This article covers its real-world applications across industries like image recognition, natural language processing, and more. Read on to know everything about neural network in machine learning!

This article was published as a part of the Data Science Blogathon.

What are Neural Networks?

Neural networks mimic the basic functioning of the human brain and are inspired by how the human brain interprets information.They solve various real-time tasks because of its ability to perform computations quickly and its fast responses.

Neural Network in macine learning

Artificial Neural Network has a huge number of interconnected processing elements, also known as Nodes. These nodes are connected with other nodes using a connection link. The connection link contains weights, these weights contain the information about the input signal. Each iteration and input in turn leads to updation of these weights. After inputting all the data instances from the training data set, the final weights of the Neural Network along with its architecture is known as the Trained Neural Network. This process is called Training of Neural Networks.These trained neural networks solve specific problems as defined in the problem statement.

Types of tasks that can be solved using an artificial neural network include Classification problems, Pattern Matching, Data Clustering, etc.

Importance of Neural Networks

We use artificial neural networks because they learn very efficiently and adaptively. They have the capability to learn “how” to solve a specific problem from the training data it receives. After learning, it can be used to solve that specific problem very quickly and efficiently with high accuracy.

Some real-life applications of neural networks include Air Traffic Control, Optical Character Recognition as used by some scanning apps like Google Lens, Voice Recognition, etc.

What are Neural Networks Used For?

Neural networks are employed across various domains for:

  • Identifying objects, faces, and understanding spoken language in applications like self-driving cars and voice assistants.
  • Analyzing and understanding human language, enabling sentiment analysis, chatbots, language translation, and text generation.
  • Diagnosing diseases from medical images, predicting patient outcomes, and drug discovery.
  • Predicting stock prices, credit risk assessment, fraud detection, and algorithmic trading.
  • Personalizing content and recommendations in e-commerce, streaming platforms, and social media.
  • Powering robotics and autonomous vehicles by processing sensor data and making real-time decisions.
  • Enhancing game AI, generating realistic graphics, and creating immersive virtual environments.
  • Monitoring and optimizing manufacturing processes, predictive maintenance, and quality control.
  • Analyzing complex datasets, simulating scientific phenomena, and aiding in research across disciplines.
  • Generating music, art, and other creative content.

Types of Neural Networks in Machine Learning

Explore different kinds of neural networks in machine learning in this section:

(i) ANN

ANN is also known as an artificial neural network. It is a feed-forward neural network because the inputs are sent in the forward direction. It can also contain hidden layers which can make the model even denser. They have a fixed length as specified by the programmer. It is used for Textual Data or Tabular Data. A widely used real-life application is Facial Recognition. It is comparatively less powerful than CNN and RNN.

(ii) CNN

CNNs is mainly used for Image Data. It is used for Computer Vision. Some of the real-life applications are object detection in autonomous vehicles. It contains a combination of convolutional layers and neurons. It is more powerful than both ANN and RNN.

(iii) RNN

It is also known as RNNs. It is used to process and interpret time series data. In this type of model, the output from a processing node is fed back into nodes in the same or previous layers. The most known types of RNN are LSTM (Long Short Term Memory) Networks

Now that we know the basics about Neural Networks, We know that Neural Networks’ learning capability is what makes it interesting. There are 3 types of learnings in Neural networks, namely

  1. Supervised Learning
  2. Unsupervised Learning
  3. Reinforcement Learning

Supervised Learning

As the name suggests, it is a type of learning that is looked after by a supervisor. It is like learning with a teacher. There are input training pairs that contain a set of input and the desired output. Here the output from the model is compared with the desired output and an error is calculated, this error signal is sent back into the network for adjusting the weights. This adjustment is done till no more adjustments can be made and the output of the model matches the desired output. In this, there is feedback from the environment to the model.

Supervised Learning |

Unsupervised Learning 

Unlike supervised learning, there is no supervisor or a teacher here. In this type of learning, there is no feedback from the environment, there is no desired output and the model learns on its own. During the training phase, the inputs are formed into classes that define the similarity of the members. Each class contains similar input patterns. On inputting a new pattern, it can predict to which class that input belongs based on similarity with other patterns. If there is no such class, a new class is formed.

Unsupervised Learning | Types of Neural Network in Machine Learning

Reinforcement Learning 

It gets the best of both worlds, that is, the best of both Supervised learning and Unsupervised learning. It is like learning with a critique. Here there is no exact feedback from the environment, rather there is critique feedback. The critique tells how close our solution is. Hence the model learns on its own based on the critique information. It is similar to supervised learning in that it receives feedback from the environment, but it is different in that it does not receive the desired output information, rather it receives critique information.

Reinforcement Learning, neural network in machine learning

How Does a Neural Network work?

According to Arthur Samuel, one of the early American pioneers in the field of computer gaming and artificial intelligence, he defined machine learning as:

Example

Suppose we arrange for some automatic means of testing the effectiveness of any current weight assignment in terms of actual performance and provide a mechanism for altering the weight assignment so as to maximize the performance. We need not go into the details of such a procedure to see that it could be made entirely automatic and to see that a machine so programmed would “learn” from its experience.

NNs

Working Explained

An artificial neuron can be thought of as a simple or multiple linear regression model with an activation function at the end. A neuron from layer i will take the output of all the neurons from the later i-1 as inputs calculate the weighted sum and add bias to it. After this is sent to an activation function as we saw in the previous diagram.

NN in machine learning

The first neuron from the first layer is connected to all the inputs from the previous layer, Similarly, the second neuron from the first hidden layer will also be connected to all the inputs from the previous layer and so on for all the neurons in the first hidden layer.

For neurons in the second hidden layer (outputs of the previously hidden layer) are considered as inputs and each of these neurons are connected to previous neurons, likewise. This whole process is called Forward propagation.

After this, there is an interesting thing that happens. Once we have predicted the output it is then compared to the actual output. We then calculate the loss and try to minimize it. But how can we minimize this loss? For this, there comes another concept which is known as Back Propagation. We will understand more about this in another article. I will tell you how it works. First, the loss is calculated then weights and biases are adjusted in such a way that they try to minimize the loss. Weights and biases are updated with the help of another algorithm called gradient descent. We will understand more about gradient descent in a later section. We basically move in the direction opposite to the gradient. This concept is derived from the Taylor series.

Deep Learning vs Machine Learning: Neural Networks

Here’s a comparison of Machine Learning and Deep Learning in the context of neural networks:

AspectMachine LearningDeep Learning
Hierarchy of LayersTypically shallow architecturesDeep architectures with many layers
Feature ExtractionManual feature engineering neededAutomatic feature extraction and representation learning
Feature LearningLimited ability to learn complex featuresCan learn intricate hierarchical features
PerformanceMay have limitations on complex tasksExcels in complex tasks, especially with big data
Data RequirementsRequires carefully curated featuresCan work with raw, unprocessed data
Training ComplexityRelatively simpler to trainRequires substantial computation power
Domain SpecificityMay need domain-specific tuningCan generalize across domains
ApplicationsEffective for smaller datasetsParticularly effective with large datasets
RepresentationsRelies on handcrafted feature representationsLearns hierarchical representations
InterpretabilityOffers better interpretabilityOften seen as a “black box”
Algorithm DiversityUtilizes various algorithms like SVM, Random ForestMostly relies on neural networks
Computational DemandLighter computational requirementsHeavy computational demand
ScalabilityMay have limitations in scaling upScales well with increased data and resources

Deep Learning Vs. Neural Network

Neural networks and deep learning are related but distinct concepts in the field of machine learning and artificial intelligence. It’s important to understand the differences between the two.

Neural Networks

A neural network is a computational model inspired by the structure and function of biological neural networks in the human brain. It consists of interconnected nodes, called artificial neurons, that transmit signals between each other. The connections have numeric weights that can be tuned, allowing the neural network to learn and model complex patterns in data.

Neural networks can be shallow, with only one hidden layer between the input and output layers, or they can have multiple hidden layers, making them “deep” neural networks. Even shallow neural networks are capable of modeling non-linear data and learning complex relationships.

Deep Learning

Deep learning is a subfield of machine learning that utilizes deep neural networks with multiple hidden layers. Deep neural networks can automatically learn hierarchies of features directly from data, without requiring manual feature engineering.

The depth of the neural network, with many layers of increasing complexity, allows the model to learn rich representations of raw data. This depth helps deep learning models discover intricate structure in high-dimensional data, making them very effective for tasks like image recognition, natural language processing, and audio analysis.

Key Differences

While all deep learning models are NNs, not all NN are deep learning models. The main distinction is the depth of the model:

  • Deep learning models have many hidden layers (often more than 5 or even hundreds), while shallow neural networks have only one or a few hidden layers.
  • Deep learning models can automatically learn features from raw data, while shallow networks often require manual feature engineering.
  • Deep learning models excel at finding patterns in highly complex, high-dimensional data like images, audio, and text.
  • Shallow neural networks are simpler and can be effective for modeling less complex data with fewer features.

Neural networks provide a general framework for machine learning models inspired by the brain, while deep learning leverages the power of deep NN to tackle complex problems with raw, high-dimensional data. Deep learning has achieved remarkable success in many AI applications, but shallow NN still have their uses, especially for less complex tasks or when interpretability is important.

Conclusion

Congrats on completing the first article of this series!

We began by introducing you to actual Neural Network in machine learning, outlining their various types to provide an overview and a sense of Neural Networks, aiding your understanding of the concept. This foundation helps you become acquainted with Neural Networks in the context of machine learning, including Support Vector Regression (SVR) and Support Vector Machine (SVM), which are different but important techniques within this field.

Now that you have your foundations established, in the next article, We will read about a few other important concepts like various types of activation functions, when to use them, their graphs, and code snippets so that you can implement them yourselves too.

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Frequently Asked Question

Q1. What are the 3 different types of neural networks? 

A. The three types are Feedforward Neural Networks (FNN), Recurrent NN (RNN), and Convolutional NN (CNN), each tailored for distinct tasks in machine learning.

Q2. What is a neural network example?

A. An example is recognizing handwritten digits. A neural network processes pixel data to classify digits based on patterns it learns during training.

Q3. What does CNN neural network stand for?

A. CNN stands for Convolutional Neural Network. It’s specialized for processing grid-like data, such as images or text data represented as sequences.

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VARIN ANAND 28 Mar 2024

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