A neural network is a system of programs and data structures that approximates the operation of the human brain. A neural network usually involves a large number of processors operating in parallel. Each part has its own small specialty of knowledge and access to data in its local memory. It works the same way as the biological nervous system works. This type of system learns by example. It is configured for a specific application to do things like recognize patterns or classify data. It can be thought of as an expert in the category of information and its much easier answer what if questions. A neural network is trained or fed large amounts of data and rules about data relationships. Neural Networks can extract patterns and detect trends that are too complex for humans to take in. Neural networks are sometimes described in terms of knowledge layers. The more complex networks have deeper layers. In feed forward systems the learned relationships about data can "feed forward" to higher layers of knowledge. Examples of where you might use a neural networking is in sales forecasting, risk management, or target marketing. In the business world neural networks can be used in a variety of ways as well.
An Expert System is a system that attempts to mimic the knowledge and decisions of a human. This type of system needs to be created from the knowledge of a human expert. This is an artificial intelligence based system that converts the knowledge of an expert in a specific subject into a software code. This code can be merged with other such codes based on the knowledge of other experts and used for answering questions or queries submitted through a computer. In today's society expert systems attempt to solve problems. There are three different parts that an expert systems typically consists of. First, a knowledge base which contains the information acquired by interviewing experts, and logic rules that govern how that information is applied. Second, an interference engine that interprets the submitted problem against the rules and logic of information stored in the knowledge base. Third, interface that allows the user to express the problem in a human language such as English. The system must be a specialist, justify its conclusions, be able to learn, and estimate the reliability of its answer.
The difference between the two is quite simple. Expert systems technology is generally regarded as simpler
and more widely used than neural network technology. An expert system uses sets
of rules and data to produce a decision or recommendation. Neural networks, on
the other hand, attempt to simulate the human brain by collecting and
processing data for the purpose of “remembering” or “learning”. The primary
difference between an expert system and a neural network is that a neural
network can adapt its criteria to better match the data it analyzes, while an
expert system produces results without adjusting for changes in the analyzed
data. Many resources for both technologies can be found on the Internet, from
simple explanations to elaborate demonstrations.