Expert system

An expert system is a special kind of computer program used in artificial intelligence. It tries to act like a human expert when solving problems. These systems use a set of knowledge, written as simple if–then rules. Unlike normal computer programs, expert systems work through these rules to find answers.

Expert systems were some of the first successful AI programs. They started in the 1970s and became popular in the 1980s. Many people thought they would change the future of AI before other methods, like artificial neural networks, became popular.

An expert system has two main parts. The first is a knowledge base, which stores all the facts and rules. The second is an inference engine, which uses those rules to learn new facts. This engine can also explain how it found its answers and spot any mistakes.

History

Early development

In the late 1940s and early 1950s, computers started to appear. Scientists wanted them to help make important decisions, like in medicine. They created simple computer systems to help with medical diagnoses using symptoms and test results. These early systems were the beginning of what later became known as expert systems, but they had limits.

Formal introduction and later developments

Expert systems were formally introduced around 1965 by researchers at Stanford, led by Edward Feigenbaum. They worked on complex areas like diagnosing diseases and identifying molecules. These systems were some of the first successful examples of artificial intelligence software.

In the 1980s, expert systems became popular. Universities taught about them, and many big companies used them. With personal computers, these systems became more accessible. By the 1990s, standalone expert systems were less common, but their ideas continued in other technologies. Recently, there has been new interest in using rule-based systems in business. Modern systems use methods from machine learning and data mining to improve decision-making.

Software architecture

An expert system is a special kind of computer program that acts like a human expert by using knowledge to solve problems. It has several important parts: a knowledge base, an inference engine, an explanation tool, a way to get new knowledge, and a user interface.

The knowledge base holds facts about the world. Early expert systems kept these facts as simple statements. Later ones used more organized structures, like groups of related items.

The inference engine is the part that thinks. It looks at the facts, uses rules to make new discoveries, and can even explain how it reached its conclusions. There are two main ways it works: one starts with known facts and finds new ones, while the other starts with a goal and checks if it can be proven.

Advantages

Expert systems help make important information easy to understand. They use simple rules that experts can read and change. This makes it easier to update and maintain the system.

One big advantage is that expert systems can be set up quickly. By entering a few rules, a working version can be ready in just days, much faster than traditional programming projects. Expert systems also offer benefits like reliable responses, the ability to combine different areas of knowledge, clear explanations of how problems are solved, quick answers, and lower costs for users.

Disadvantages

Expert systems can have some problems. One big problem is that it can be hard to get information from human experts, because they are often very busy and not easy to reach. Because of this, researchers made tools to help collect and organize expert knowledge more easily.

Other issues include making these systems work well with large databases and other computer programs. Early expert systems used special programming languages and machines that were not common in businesses, so connecting them was tricky. As technology improved, these problems got better.

When an expert system has a lot of knowledge, it can be hard for the computer to process all the information quickly. Checking that all the rules work together can also be difficult with many rules. Updating the knowledge and adding new information is another challenge. Because of these and other issues, newer approaches to artificial intelligence, like machine learning, have become more popular.

Applications

Expert systems can be used in many ways. They help computers make decisions like a human expert.

One early example, Hearsay, tried to recognize voices by finding patterns in sound data. Other systems used similar ideas to analyze sonar data.

CADUCEUS and MYCIN are systems that help doctors. A person tells the computer about their health problems, and the computer suggests a possible diagnosis.

Dendral helped scientists identify molecules. It was also used in businesses, like helping salespeople set up computers or process loan applications.

SMH.PAL is a system to help assess students with multiple disabilities.

GARVAN-ES1 is a medical system that gives advice on test results. It was one of the first systems used regularly in hospitals around the world.

Mistral monitors the safety of dams. It checks data to see how well a dam is doing. It has been used on dams in Italy, Brazil, and other places.