Simulation

A simulation is a way to show how things work.

It is like a pretend version of the real world. You can use a computer to make it.

Sometimes, the real thing is too dangerous to touch. A simulation lets you practice safely.

You can try new things to see what happens.

People use them for many jobs. Pilots use them to learn how to fly. Some people use them to play video games.

It can even help us study nature. We can see how things change over time.

Simulations help us learn about our world.

They make big ideas easy to see.

A simulation is a way to copy a real system. It can be a real process or an idea.

Sometimes we use a model to make a simulation. A model shows the main parts of a system. A simulation shows how those parts change over time. Many people use computers to run these tests. This helps us study things that are hard to reach. Some things might be too dangerous to touch. Other things might not even exist yet.

There are many ways to use simulations. Some are physical. This means we use real objects that are smaller or cheaper. Others are interactive. This is called human-in-the-loop simulation. It means a person is part of the test.

Pilots use flight simulators to practice flying.

Sailors use ship bridge simulators to learn.

We also talk about fidelity. Fidelity is how close a simulation is to the real thing. High fidelity means it looks and acts almost exactly like reality.

Simulations help us learn about science, math, and even video games.

A simulation is a way to copy a real system or a process.

It can represent things that exist or things that are only imagined. People often use the word "model" when they talk about simulations. A model shows the main parts of a system. A simulation shows how those parts change as time goes by. This helps us study things that are too hard to reach. It is also useful for things that are too dangerous to touch.

Some systems are being designed but are not built yet. Simulations let us see what might happen before we build them.

There are many ways to make a simulation work. Some use physical objects that are smaller or cheaper than the real thing. Other simulations happen inside a computer. These are often called "sims."

In a computer simulation, you can change variables to see new results. Some simulations use random changes, which is called stochastic simulation. Others use set rules so the result is always the same. This is called deterministic simulation. There are even hybrid simulations that mix different ways of working. These tools help scientists study everything from tiny cells to huge economies.

In the past, simulations grew in many different areas on their own. In the 20th century, things began to change. Scientists studied systems theory and cybernetics. At the same time, computers started to spread to many different fields. This helped bring different types of simulation together.

Now, we have a more organized way to look at them. We can even use the web to access simulations as a service. This makes it easier for people to use these powerful tools.

Researchers use many specific types of simulations today. One kind is called human-in-the-loop simulation. This is an interactive type where a person is part of the test.

Pilots use flight simulators to practice flying planes.

Sailors use ship bridge simulators to learn how to steer. There is also parallel simulation, which uses many processors at once. This makes the work go much faster.

Some simulations use many computers at once to share data. This is known as Distributed Interactive Simulation.

We often talk about fidelity when looking at a simulation. Fidelity describes how accurate the copy is.

Low fidelity is the simplest kind. It only does the bare minimum to work. Medium fidelity responds to things but has limited accuracy. High fidelity is very close to the real thing. It can be almost indistinguishable from reality.

This helps engineers find out why machines fail. It also helps computer scientists test new designs safely.

A simulation is an imitative representation of a process or system. It can represent something real or something imagined. Scientists and engineers often use simulations to study complex systems. This is helpful when the real system is too dangerous to touch. It is also useful if the system is too expensive or not yet built. Sometimes, a real system is simply impossible to access. By using a simulation, we can explore different conditions and see the results.

To understand how this works, we must distinguish between a model and a simulation. A model represents the key characteristics or behaviors of a system. A simulation represents how that model evolves over time. You can think of the model as a blueprint and the simulation as the building process. Simulation is essentially experimentation using a model. Often, computers execute these simulations to handle complex calculations. This allows researchers to virtually investigate how a system behaves under different variables.

There are several distinct ways to classify simulations based on their mechanics. Continuous simulation uses numerical integration of differential equations to follow time smoothly. In contrast, discrete-event simulation studies systems that only change at specific moments. For example, an epidemic simulation might only change when someone gets sick or recovers. Hybrid simulations combine these two methods to reduce mathematical errors. There is also stochastic simulation, which uses random variations and Monte Carlo techniques. This means running the same test multiple times will produce different results within a specific range. Deterministic simulations are the opposite, as they use fixed algorithms to produce identical results every time.

Simulations can also be categorized by how they are built and run. Physical simulation involves using real objects that are smaller or cheaper than the original. Interactive simulation, or human-in-the-loop simulation, includes a person in the process.

Pilots use flight simulators to practice, and sailors use ship bridge simulators to learn.

In terms of computing, a stand-alone simulation runs on one workstation. Distributed Interactive Simulation uses more than one computer to share resources. Parallel simulation speeds up the work by distributing the workload over multiple processors. Finally, interoperable simulation allows different models to work together over a network.

Historically, different fields developed their own types of simulations independently. This changed during the 20th century due to new scientific ideas. The study of systems theory and cybernetics helped unify these different approaches. As computers became more common across all fields, the view of simulation became more systematic. Today, we can even access modeling and simulation as a service over the web. This makes these powerful tools available through cloud computing. This evolution has turned simulation from a niche tool into a global scientific standard.

When evaluating a simulation, experts look at its fidelity. Fidelity describes how accurately a simulation imitates its real-life counterpart. It is usually classified into three levels: low, medium, and high. Low fidelity is the minimum required to provide inputs and outputs. Medium fidelity responds to stimuli but has limited accuracy. High fidelity is nearly indistinguishable from the real system.

High fidelity is essential for tasks like failure analysis. This helps engineers identify why equipment fails in a safe, virtual environment.

Simulation connects to many different scientific and technical disciplines. In computer science, an emulator is a type of simulator. It allows a computer to run programs designed for a different or obsolete machine. This is helpful for testing new hardware before it is even built. In biochemistry, projects like Folding@home use computer simulations to study complex molecules. In economics, simulations help researchers understand human and social systems. Whether it is studying airflow over an engine or predicting the spread of a disease, simulation provides a window into the workings of our world.