A Complete Guide To Reinforcement Learning (With Types)

By Indeed Editorial Team

Published 16 May 2022

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

Reinforcement learning refers to the training of machine learning models to make decisions in a complex environment. These learning techniques are based on an iterative trial-and-error basis where the artificial intelligence gets rewards or penalties based on the actions performed until the developer gets the expected result they want. In this article, we discuss reinforcement-based learning, its importance, the process, the working, the components involved, the challenges faced, its types and the difference between it, machine learning and deep learning, along with some examples for a better understanding.

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What is reinforcement learning?

Reinforcement learning helps an intelligent system test new actions and change the course in case of failures, helping deliver accurate decisions. The goal is to discover the sequence of actions to maximise the reward in the programmer's absence. Reinforcement algorithms are versatile, as they can adapt to the new environment.

The technology industry is driving rapid transformations with the help of AI and this is a term that is popularly discussed, followed and researched in this sector. As humans learn to change from experiences, machines and software use reinforcement algorithms to decide ideal behaviour based upon the feedback from the environment.

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Why is reinforcement learning important?

Reinforced learning is vital to the processes involved in machine learning and artificial intelligence. It is essential to establish the parameters and operational standards for soft AI while retrieving and displaying information. It also creates an interactive environment for computerised agents to build future frameworks, alongside reinforcing computer code and programming for AI applications.

How a reinforcement-based learning process works

In this type of learning process, the data input travels through the environment and performs a specific set of actions. If the actions are correct, the programmer rewards the agent by reinforcing the outcome of the action. Alternatively, if the actions are incorrect, the programmer punishes the agent. Here, punishment refers to the reconfiguration of a sophisticated software code that establishes the parameters for recognition in the agent, that support it to identify incorrect actions before performing them. This process helps in reinforcing the agent to perform the correct processes to get the desired outcome.

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Components of reinforcement-based learning

The reinforcement parameters applied within machine learning include an agent and the environment in which the agent performs. Apart from these two components, there are a few more elements that contribute to the learning system:

  • Policies: Policies are used to define the agent's behaviour during a specific period. It includes implementing essential maps that state the environment to the action and the agent's response to that environment.

  • Rewards: Rewards are an essential part of the reinforcement process. They help in establishing the goals, where the agent receives a reward signal for achieving the desired outcome.

  • Value functions: Value functions represent the total number of rewards the agent can expect in the future for initiating actions in its existing environmental state.

  • Environment model: Using models of the environment helps in reproducing behaviours that are specific to that environment. This aids in making inferences about how an environment may affect the response of an agent.

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Challenges in reinforcement-based learning

Reinforcement-based learning and its implementation come with their own set of challenges as well. Here are some of the primary reasons that hamper the prevalence of this type of learning:

Preparing the stimulation environment

One of the major challenges in reinforcement-based learning is preparing a stimulating environment that depends on the task to be performed. For simpler models, it can be a straightforward process. It becomes more challenging with complex models, as transferring the model from the training environment to the real world can be difficult.

Scaling the neural network controlling agent

The only way to communicate with the network is through the system of rewards and penalties. Here, acquiring new knowledge and information can cause the old one to be erased from the system. Programmers require to consider all possible environments and accordingly create rewards and penalties individually for optimum efficiency.

Reaching a local optimum

The agent usually performs the task as it is, rather than performing it in an optimal or required way. Similarly, the programmer also optimises the reward for performing the task. If the agent is stuck in a local optimum, the programmer requires reducing the learning rate or adding a curiosity-based term to prompt the agent to reach new states.

State overload

During positive learning, too much reinforcement can lead to state overload. In such a situation, the environmental state can become overloaded with input information, which eventually diminishes the output. A balance of positive and negative reinforcement enables the agent to achieve maximum efficiency.

High data reliance

As this method of machine learning is used to solve complex problems, it can require huge amounts of data for the agents and the environment to perform effectively. Considering that environments are non-stationary, the programmer visualises and codes multiple scenarios and adds relevant data. This also limits the application of reinforcement-based learning to sectors where big data is readily available for simulation.

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Types of reinforcement-based learning

Reinforcement-based learning requires engineers to apply the following learning methods to train agents and environments to get the desired results:

Positive reinforcement

Positive reinforcement occurs when the agent takes a specific set of actions or performs a specific behaviour. This helps in increasing the frequency and the strength of the desired behaviour. Positive reinforcement confirms the validity of the actions, which increases the likelihood of the agent repeating similar behaviour.

Negative reinforcement

Negative reinforcement strengthens undesirable actions and behaviours due to negative conditions that an agent is supposed to avoid. It helps the agent and the environment understand the minimum standards of performance to meet the minimum behavioural standards. This results in achieving the desired functionality level that developers set for the system.

Applications of reinforcement-based learning

It is a widely used method in the industrial sector, with growing opportunities in other sectors. Here are some examples of industries that make use of reinforcement-based learning:

Robotics

In structured environments such as the assembly line of an automobile manufacturing plant, robots with pre-programmed behaviours can be useful as the tasks are repetitive. This type of learning provides robotics with a framework and a set of tools for behaviours. As it is achievable without supervision, it is a common application in robotics for exponential growth.

Autonomous vehicles

Most autonomous or automated cars, trucks, drones and ships use reinforcement algorithms in their driving systems, as autonomous driving systems require considering multiple perceptions and planning accordingly in uncertain situations. This type of learning handles tasks like vehicle path planning and motion prediction. The system ensures that the vehicle makes use of the quickest and safest route to reach its destination.

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Difference between reinforcement learning, deep learning and supervised learning

Though these terms overlap to some extent, there is a significant difference between the three types of learning. It is essential to know the key differences between the three to ensure that you do not use them interchangeably. These are:

Reinforcement learning

As we have seen above, reinforcement-based learning is a system of rewards and penalties which compels the computer to solve the problem itself. Human involvement is limited to changing the environment and tweaking the rewards and penalties system. The programmer focuses on the prevention of the exploitation of the system and on motivating the machine to perform in the desired way.

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Deep learning

Deep learning includes several layers of neural networks that are specially designed to perform sophisticated tasks. The construction of this model resembles the working of a human brain but is much simpler. The neural networks learn abstract features about particular data. Each layer uses the outcome of the previous one as an input. The entire network functions as a single system.

Supervised learning

Supervised learning is a part of machine learning where computers have the ability to progressively improve the performance of a specific task without direct programming. It occurs when a programmer provides labels for every training input into the machine's learning system. Machine learning also includes unsupervised machine learning, which takes place when the model is just provided with data input and no labels. It has to figure out the hidden structures within by analysing the data. The designer might be unaware of what the structure is or what the model is going to find.

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