Rules based system

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A rule-based system is a knowledge-based system in which rule-based reasoning takes place.

Rule-based systems consist of

The rules are as follows: IF ... THEN ... ELSE (IF THEN ELSE). For example, a rule could look like this:

IF the stove is hot AND there is no pot on the stove, THEN turn off the stove

The IF part of the rule is also referred to as the premise , the THEN part as the conclusion .

The task of the control system is to identify suitable rules, apply selected rules and update the database.

Selection mechanisms for the next rule to be applied are either data-driven , goal- driven or a combination of these two possibilities.

Data-driven ( forward chaining ) or forward chaining means
There is a fact - a "IF fact THEN ..." rule is applied. Here the attempt is made to make a diagnosis on the basis of facts, i.e. to arrive at a goal that is mostly still unknown.
Target-driven ( backward chaining ) or backward chaining means the backward approach
There is a fact - an "IF ... THEN fact" rule is applied. Here an attempt is made to prove a hypothesis.

In addition to case-based systems, rule-based systems are the basis of expert systems .

The rules are usually managed in a business rule repository as part of a business rule management system .

Applications

Rule-based systems are increasingly used in production planning and control , especially in branches of industry with a wide variety of consumer and investment goods such as the furniture industry, mechanical engineering or the electrical industry . A well-known example is the automotive industry , in which vehicles are defined by features that can be selected and put together by the customer using a product configurator . During configuration, reference is made to these features in the "IF ... THEN" rules in order to enforce certain combinations of features (commandments) or prevent them (prohibitions). Example: If the customer orders a "convertible", he may not order a "sunroof" at the same time, or if he orders a fully automatic "air conditioning", he must also order a more powerful "battery". Rules are also drawn up for the distribution of worldwide vehicle orders to the vehicle and assembly plants of an automobile manufacturer. The rules of an automobile manufacturer can include thousands of such product and production rules. If the characteristics for the definition of a product meet the characteristics of an ideal Boolean algebra , then - due to the complementarity - prohibitions can always be expressed as commandments (and vice versa). If it is a multi-level algebraic lattice, then rules can also be 'inherited' on subsets.

See also

swell

  1. ↑ Herlyn, Wilmjakob: PPS in the automotive industry ; Hanser Verlag, Munich 2012, p. 99, p. 103, p. 168 ff.
  2. ↑ ibid., S. P. 87 ff

literature

  • Herlyn: PPS in the automotive industry - production program planning and control of vehicles and assemblies . Hanser Verlag, Munich 2012, ISBN 978-3-446-41370-2 .