# What is Bayesian Network & Why its Important?

Every day, data science specialists use innovative and advanced AI technologies, Machine Learning, and Advanced analytics to tackle various business challenges. The primary goal of addressing these challenges is to provide dependable, efficient, and error-free solutions. However, when using these methodologies, it’s critical to provide actionable

data to drive the model output so that end-users may effectively leverage these solutions to make critical business choices. This requirement applies to AI solutions developed across industries.

One such machine-learning approach that focuses on generating actionable information is the Bayesian Network. In this article, we will discuss the Bayesian network in detail.

## Understanding the Bayesian Network

The Bayesian network is a crucial computer technique for coping with unpredictable occurrences and solving associated problems. Let’s start with probabilistic models before moving on to Bayesian networks.

After determining the link between variables using probabilistic models, you may compute the various probabilities of those two values. A Probabilistic Graphical Model is another name for a Bayesian Network (PGM).

Conditional models, for example, require a large quantity of data and information to compute all conceivable outcomes, and putting all of those possibilities to the test is challenging. The simplification of the probability of the random variables is extremely useful.

It has two subdivisions:

• Table of conditional probabilities
• Directed acyclic graph

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## What is it used for?

Bayesian belief networks are used in developing search engines, diagnosing various diseases, filtering spam emails, gene regulatory networks, and for many more similar works.

This network’s primary goal is to comprehend the idea of causality relationships. Let’s conceive of this as a sickness diagnostic. The symptoms are right in front of your eyes, and you can diagnose the disease just by looking at them. For example, when a new patient comes in, doctors assess their symptoms to see if they have any illnesses. In addition, the network provides probabilities for each illness.

Other logical issues and judgments might benefit from similar causality relationships, providing spectacular outcomes.

The Bayesian belief network determines the associations between numbers.

## How does it work?

The following is a rundown of how the Bayesian network works:

• We employ the Bayes theorem to operate the Bayesian network. The theorem is most commonly used in the context of difficult situations. In contrast to other methodologies where probabilities are determined based on past evidence, this theorem studies probability or confidence in a result. The Bayesian Network is based on the concepts of dependency and independence.
• A random number or variable that is unaffected by other factors is said to be independent. On the other hand, a dependency or dependent variable is a random variable with an undetermined probability and is dependent on other factors.
• In this network, the term conditional independence describes the connection between multiple random variables. The variable may be conditional independent.

A Bayesian Belief network consists of 2 components:

• Actual numbers
• Casual components

## What is an Influencer Diagram in a Bayesian Network?

An Influence diagram is an extended type of Bayesian network that illustrates and solves decision problems under uncertain knowledge. It is made up of nodes and arcs.

Each node represents a random variable, which is either continuous or discontinuous. Arcs or directed arrows represent the causal link or conditional probabilities between random variables. The arrows are directed connections used to connect two nodes to each other.

The links indicate that one node directly impacts the other, and if there are no directed links, nodes are independent of one another.

Bayesian belief networks have several advantages, including the ability to show different probabilities of variables. Here are a few examples:

## Pros of The Bayesian Network

• Graphical and visual networks serve as a model for visualizing the structure of probability and developing new model designs.
• Computations are used to solve complex probability issues quickly.
• Bayesian networks can analyze and inform you if a specific trait is taken into account in a note throughout the decision-making process, and if required, push it to do so. To decide on an issue, the network ensures correct and accurate evaluation of all the parameters and characteristics.
• Other networks and learning approaches are not as extensible and flexible as Bayesian Networks. A few probability and graph edges are required to add a new item to the network. As a result, it’s an excellent network for adding new data to an existing probabilistic model.
• A Bayesian Network’s graph is beneficial. It can be read by both computers and humans. Unlike specific networks, such as neural networks, which humans cannot read, it can be read by both.

## Constraints of the Bayesian Network

• The biggest drawback is that there is no commonly accepted way for creating networks from data. There have been several breakthroughs in this direction, but no conqueror has emerged in a long time.
• In comparison to other networks, Bayesian Networks are challenging to create. As a result, only the individual who built the network can leverage causal influences. In comparison, neural networks have an advantage since they can learn multiple patterns and aren’t confined to the originator.
• The Bayesian network fails to define cyclic interactions, such as airplane wing deflection and the fluid pressure field around it. The pressure is dependent on the deflection, and the deflection is dependent on the pressure. This network fails to define and make judgments on a closely linked problem.
• The network is costly to construct.
• On high-dimensional data, it performs poorly.
• It’s difficult to decipher and requires copula functions to distinguish between consequences and causes.

## How are Bayesian Networks Developed?

To create a Bayesian network, you must first ask yourself three questions:

• What are my project’s random variables?
• How are the variables related?
• Are they dependent on each other or independent variables?
• How are the probabilities of each variable in my project distributed?

All of these issues may be answered by an expert, who can also recommend a design for the Bayesian Belief Network model. Specialists usually define the architecture of such models, but you must derive the probability distributions from the available data. The data may be used to determine probability distributions and graph structure. However, this is a time-consuming operation.

You may compute the graph using algorithms. For example, to calculate the distribution parameters, assume a Gaussian distribution for continuous random variables.

You may utilize the Bayesian Belief Network for logical reasoning, such as gaining solutions to situational situations and making judgments, once it is ready for any domain.

The reasoning is conducted by the model’s interpretation of a particular problem or circumstance. If the outcome of certain events is known, for example, the model estimates all the probability of causes and other alternative results automatically.

## Bayesian Neural Network: What is it?

Bayesian Neural Networks (BNNs) uses posterior inference to control overfitting. In a broader sense, the Bayesian approach employs statistical methodology to ensure that everything, including model parameters, is assigned a probability distribution (weights and biases in neural networks). Variables that can accept a specified value in programming languages will provide the same outcome every time you access that variable.

## Conclusion

In Artificial Intelligence, Bayesian networks are widely employed to deal with business activities, one of which is spam screening in your email account. It’s also used in image processing, where it help transform photos into various digital forms. BNNs have also made significant contributions to medical research and innovation, such as Biomonitoring that uses markers to assess the number of tissues existing in our bodies.

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## What are the pros of Bayesian Neural Networks?

As a technique to avoid overfitting, Bayesian neural networks effectively tackle issues in fields where data is limited. Molecular biology and medical diagnostics are two examples of applications (areas where data often come from costly and difficult experimental work). Bayesian networks are helpful in improving performance for a wide range of jobs, but scaling to enormous challenges is exceedingly challenging. BNNs allow you to automatically calculate an error associated with your predictions when dealing with data from unknown targets.

## Which equation is used to calculate Bayesian network problems?

The formula or equation used to calculate Bayes problems is: P(Xi|Xi-1,........., X1) = P(Xi |Parents(Xi ))

## Can Bayesian Networks be used in SNAs?

SNA is a type of contest in which you attempt to decode and comprehend the structure of a social network. You can also understand the relevance of the nodes, but we don't know what the network's choice will be. This is where the BBNs showcase their usability. We can use BBNs to simplify the problems. 