HVAC Control in the New Millennium.pdf - HVAC.Amickracing

HVAC Control in the New MillenniumThe expert system operates in one of two modes. The expert orknowledge acquisition mode is used to enter rules into the system. Theuser or consultation mode is used to solve the problem (Figure 6-4).The game of Animal acts like an expert system. When it asks forquestions, it is operating in the knowledge acquisition mode. It uses theanswers to these questions to construct or add to its expert system ofanimal classification. Similar classification expert systems are used inmedicine, publishing, geology, and construction.The expert system for the game of Animal works with completeand certain information. Other expert systems work with uncertain orincomplete information. This includes medical programs used to diagnoseand prescribe treatment for specific problems like bacterial infectionsof the blood.Expert systems have been used in the following control areas:• fault diagnosis and troubleshooting,• quality control,• control system synthesis,• statistical control and• alarm management.Artificial neural networks (ANN) can be used as a tool for examiningdata and determining relationships. They are useful for capturingrelationships among measurements and modeling. Compared to thetechnology of expert systems, the technology of neural networks isnewer.Figure 6-4. One type of expert system operates in an expert modewhile learning new facts and in a user mode while using its knowledgebase.©2001 by The Fairmont Press, Inc. All rights reserved.