Course Instructor: K ashif I hsan 1

Chapter # 3 Kashif Ihsan, Lecturer CS, MIHE2

Applications of Expert System Kashif Ihsan, Lecturer CS, MIHE3

PUFF It is a medical expert system used for diagnosis of respiratory conditions. Kashif Ihsan, Lecturer CS, MIHE4

PROSPECTOR It is used by geologists to identify sites for mining or drilling. Kashif Ihsan, Lecturer CS, MIHE5

PROSPECTOR Prospector is another example of expert systems. It provides help to the Geologists, to locate ore deposits. Its knowledge base contains rules and heuristic data (experience-based techniques). It also contain the taxonomy of various kinds of minerals and rocks. ORE means rocks etc from which mineral/metal is obtained. TAXONOMY means naming knowledge (nomenclature). Kashif Ihsan, Lecturer CS, MIHE6

MYCIN It is a medical expert system used for diagnosing blood disorders. Kashif Ihsan, Lecturer CS, MIHE7

MYCIN It is one of the most popular expert systems of all time. It is a medical expert system that diagnoses bacterial infections and recommends antibiotic therapy. The job of the physician is just to enter the patient's age and medical history, results of laboratory tests and any additional information. The use of this program is optimal, BUT the final decision is depending upon the physician. Kashif Ihsan, Lecturer CS, MIHE8

DESIGN ADVISOR It gives advices to designers of processor chips. Kashif Ihsan, Lecturer CS, MIHE9

DENDRAL It is used to identify the structure of chemical compounds. Kashif Ihsan, Lecturer CS, MIHE10

DENDRAL It helps the chemists to identify the molecular structure of an unknown compound using its knowledge. The identification of unknown compounds is a long, difficult and expensive process. Such system can save scientists a considerable amount of time and effort. Kashif Ihsan, Lecturer CS, MIHE11

LITHIAN It gives advices to archeologists examining stone tools. Kashif Ihsan, Lecturer CS, MIHE12

Why use Expert Systems ? Human experts are not always available. An expert system can be used anywhere, any time. Human experts are not 100% reliable or consistent. Experts may not be good at explaining decisions. Kashif Ihsan, Lecturer CS, MIHE13

Problems with Expert System Limited domain. Systems are not always up to date. Expert systems don’t learn. No “common sense”. Experts needed to setup and maintain system. Kashif Ihsan, Lecturer CS, MIHE14

Legal & Ethical Issues Who is responsible if the advice is wrong?  The user?  The domain expert?  The knowledge engineer?  The programmer of the expert system?  The company selling the software? Kashif Ihsan, Lecturer CS, MIHE15

Features/Characteristics of Expert System The most obvious feature of an expert system is that it operates as an interactive system that responds to questions, asks for clarifications, makes recommendations and generally aids the decision-making process. To a user, this interactive interface is what would distinguish an expert system from any ordinary computer tool. Kashif Ihsan, Lecturer CS, MIHE16

Features/Characteristics of Expert System An expert system must have the capability to make logical inferences based on the knowledge stored. Expert systems are very domain-specific. A medical expert system cannot be used to find faults in the design of an electrical circuit. This focus on small domains is more a result of technological limitations than anything else. Kashif Ihsan, Lecturer CS, MIHE17

Features/Characteristics of Expert System Expert systems have become increasingly popular because of their specialization, albeit in a narrow field. The small size of the domain makes encoding and storing the domain-specific knowledge an economic process. Also, as specialists in many areas are scarce, and the cost of consulting them is high, an expert system catering to any of those areas can be considered to be a useful and cost- effective alternative, in the long run. Kashif Ihsan, Lecturer CS, MIHE18

Usefulness of Expert Systems Salaries of human experts are increasing continuously. Alternatively, cost for developing and maintaining expert systems continue to drop. This will indirectly greatly reduce the cost of producing expertise per user. Human experts require educational cost in millions of rupees whereas expert systems (developed once) can be copied (or reproduced) on negligible cost. Kashif Ihsan, Lecturer CS, MIHE19

Usefulness of Expert Systems Human experts can use their expertise for very limited time; whereas expert systems can live for ever.  No Retirement.  No Resignation.  No Transfer of Job.  No Death.  Always Operate at Peak Efficiency. Kashif Ihsan, Lecturer CS, MIHE20

Dealing with Uncertainty The important attribute of an expert system is its ability to deal with incomplete or uncertain information. In some case you simply say that you don’t know. Expert systems are designed to deal with inputs like this because you may not have a particular fact, the search process will take a different path. It may take longer time to come up with an answer, BUT the expert system will give you an answer. Kashif Ihsan, Lecturer CS, MIHE21

The Down Side of Expert System Development of an expert system is extremely difficult, more difficult than developing other conventional software. Good experts are hard to find. Extracting their knowledge takes very long time and is very difficult. Coding that knowledge into a computer software is also too much difficult. Kashif Ihsan, Lecturer CS, MIHE22

The Down Side of Expert Systems To implement an expert system practically, it requires high hardware specification. It can be run on a big mainframe computer. Personal computer will limit its usefulness. A human being should always provide the final judgment. Kashif Ihsan, Lecturer CS, MIHE23

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