My
This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA
Overview
Download & View My as PDF for free.
More details
- Words: 1,888
- Pages: 10
EXPERT SYSTEM Assignment no.1
Submitted ToMr.Raman Kumar
Submitted Bymonika mal Roll no.129/04
CASE STUDY OF MYCIN MYCIN is one of the most widely known of all expert system applications developed. And this despite the fact that it has never been put into practice. However, MYCIN is significant to the history of expert/knowledge-based systems for two particular reasons. First, unlike DENDRAL, which used a 7 model of a particular molecule as the basis for its reasoning, MYCIN was constructed from interviews with various doctors in the particular domain. Therefore, MYCIN contains a number of heuristic rules that are used by physicians in the identification of certain infections. The second major contribution of MYCIN was the later development of EMYCIN (Empty MYCIN). EMYCIN was the first expert/knowledge-based system shell. It took approximately 20 man-years to develop the MYCIN program. The researchers realized that if expert systems were to become a viable problem solving technique this development time must be cut. In an effort to do reduce the time to develop an expert system the researchers developed EMYCIN by taking all of the rules out of the system and leaving just an empty “shell” in which other developers in other domains could then just “plug-in” their new knowledge base. One of the best known expert systems is MYCIN (Shortliffe 1976; Davis, Buchanan and Shortliffe 1977), a program for advising physicians on treating bacterial infections of the blood and meningitis. It does reasonably well without common sense, provided the user has common sense and understands the program's limitations. MYCIN conducts a question and answer dialog. After asking basic facts about the patient such as name, sex and age, MYCIN asks about suspected bacterial organisms, suspected sites of infection, the presence of specific symptoms (e.g. fever, headache) relevant to diagnosis, the outcome of laboratory tests, and some others. It then recommends a certain course of antibiotics. While the dialog is in English, MYCIN avoids having to understand freely written English by controlling the dialog. It outputs sentences, but the user types only single words or standard phrases. Its major innovations over many previous expert systems were that it uses measures of uncertainty (not probabilities) for its diagnoses and the fact that it is prepared to explain its reasoning to the physician, so he can decide whether to accept it.
MYCIN begins with its ontology. The ontology of a program is the set of entities that its variables range over. Essentially this is what it can have information about. MYCIN's ontology includes bacteria, symptoms, tests, possible sites of infection, antibiotics and treatments. Doctors, hospitals, illness and death are absent. Even patients are not really part of the ontology, although MYCIN asks for many facts about the specific patient. This is because patients aren't values of variables, and MYCIN never compares the infections of two different patients. It would therefore be difficult to modify MYCIN to learn from its experience. The production formalism turned out to be suitable for representing a large amount of information about the diagnosis and treatment of bacterial infections. When MYCIN is used in its intended manner it scores better than medical students or interns or practicing physicians and on a par with experts in bacterial diseases when the latter are asked to perform in the same way. However, MYCIN has not been put into production use, and the reasons given by experts in the area varied Some said it would be ok if there were a means of keeping MYCIN's database current with new discoveries in the field, i.e. with new tests, new theories, new diagnoses and new antibiotics. For example, MYCIN would have to be told about Legionnaire's disease and the associated Legionnella bacteria which became understood only after MYCIN was finished. (MYCIN is very stubborn about new bacteria, and simply replies ``unrecognized response''.) Others say that MYCIN is not even close to usable except experimentally, because it doesn't know its own limitations. I suppose this is partly a question of whether the doctor using MYCIN is trusted to understand the documentation about its limitations. Programmers always develop the idea that the users of their programs are idiots, so the opinion that doctors aren't smart enough not to be misled by MYCIN's limitations may be at least partly a consequence of this ideology. An example of MYCIN not knowing its limitations can be excited by telling MYCIN that the patient has Cholerae Vibrio in his intestines. MYCIN will cheerfully recommend two weeks of tetracycline and nothing else. Presumably this would indeed kill the bacteria, but most
likely the patient will be dead of cholera long before that. However, the physician will presumably know that the diarrhea has to be treated and look elsewhere for how to do it. On the other hand it may be really true that some measure of common sense is required for usefulness even in this narrow domain. We'll list some areas of common sense knowledge and reasoning ability and also apply the criteria to MYCIN and other hypothetical programs operating in MYCIN's domain.
CASE STUDY OF E-MYCIN GENERIC NAME: erythromycin BRAND NAMES: E-Mycin, Eryc, Ery-Tab, PCE, Pediazole, Ilosone DRUG CLASS AND MECHANISM: Most infections are caused by bacteria that invade and grow in the human body. Medications that control or eradicate these bacteria are called antibiotics. Erythromycin is an antibiotic that prevents bacteria from producing proteins, which interferes with bacterial growth and multiplication, while not affecting human Erythromycin is an antibiotic used to treat many kinds of infections, including: Acute pelvic inflammatory disease Gonorrhea Intestinal parasitic infections Legionnaires' disease Listeriosis Pinkeye Rectal infections Reproductive tract infections Skin infections Syphilis Upper and lower respiratory tract infections Urinary tract infections
Whooping cough Erythromycin is also prescribed to prevent rheumatic fever in people who are allergic to penicillin and sulfa drugs. It is prescribed before colorectal surgery to prevent infection.
Most important fact about this drug Erythromycin, like any other antibiotic, works best when there is a constant amount of drug in the blood. To help keep the drug amount constant, it is important not to miss any doses. Also, it is advisable to take the doses at evenly spaced times around the clock.
Medication Some forms of erythromycin are most effective when taken on an empty stomach. Your doctor may advise you to take each dose at least 1/2 hour and preferably 2 hours before meals. Delayed release formulations may be taken with or without food. Chewable forms of erythromycin should be crushed or chewed before being swallowed. Delayed-release brands and tablets and capsules that are coated to slow their breakdown should be swallowed whole. Do not crush or break. If you are not sure about the form of erythromycin you are taking, ask your pharmacist. The liquid should be shaken well before each use. •
If you miss a dose... Take it as soon as you remember. If it is almost time for your next dose, and you take 2 doses a day, space the missed dose and the next dose 5 to 6 hours apart; if you take 3 or more doses a day, space the missed dose and the next one 2 to 4 hours apart. Never take 2 doses at the same time.
•
Storage instructions... The liquid form of erythromycin should be kept in the
refrigerator; use E.E.S. within 10 days. Do not freeze. Store tablets and capsules at room temperature in a tightly closed container.
side effects Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine whether it is safe to continue taking this medication. •
Side effects may include: Abdominal pain, diarrhea, loss of appetite, nausea, vomiting
Case study of neomycin Generic Name: neomycin (nee oh MY sin) Brand Names: Mycifradin, Neo-Fradin, Neo-Tab Neomycin is an antibiotic. Neomycin is used to reduce the risk of infection during surgery of the bowel. Neomycin is also used to reduce the symptoms of hepatic coma. Neomycin may also be used for purposes other than those listed here. Neomycin may cause damage to the kidneys and/or nerves. Kidney function and drug levels in the blood may be monitored with blood tests during treatment. Tell your doctor if you experience decreased urination, hearing loss, ringing in the ears, feeling of fullness in the ears, dizziness, numbness, skin tingling, muscle twitching, or seizures which may be signs of kidney or nerve damage. Do not take neomycin without first talking to your doctor if you have • • •
kidney disease; a blockage in the intestines; bowel disease such as Crohn's disease or ulcerative colitis;
a neuromuscular disorder such as Parkinson's disease or myasthenia gravis; • hearing loss or loss of balance due to ear problems; or • other medical problems or if you take other medications. You may not be able to take neomycin, or you may require a dosage adjustment or special monitoring during treatment if you have any of the conditions listed above. •
Neomycin side effects If you experience any of the following serious side effects, stop taking neomycin and seek emergency medical attention: • an allergic reaction (shortness of breath; closing of the throat; hives; swelling of the lips, face, or tongue; rash; or fainting); • little or no urine; • decreased hearing, ringing in the ears, or a feeling of fullness in the ears; • dizziness, clumsiness, or unsteadiness; • numbness, skin tingling, muscle twitching, or seizures; or • severe watery diarrhea and abdominal cramps. Other, less serious side effects may be more likely to occur. Continue to take neomycin and talk to your doctor if you experience • nausea or vomiting; or • diarrhea.
DIFFERENCE BETWEEN Artificial intelligence & Expert system
S.NO 1.
ARTIFICIAL INTELLIGENCE The branch of computer science concerned with making computers behave like humans. Artificial intelligence includes: games playing expert systems natural language neural networks robotics
EXPERT SYSTEM A computer application that performs a task that would otherwise be performed by a human expert. For example, there are expert systems that can diagnose human illnesses, make financial forecasts, and schedule routes for delivery vehicles. Some expert systems are designed to take the place of human experts, while others are designed to aid them.
2.
Currently, no computers exhibit full artificial intelligence (that is, are able to simulate human behavior
Expert systems are part of a general category of computer applications known as artificial intelligence
3.
Computer-based system Ability of a machine to perform designed to respond like a tasks thought to require human human expert in a given intelligence field.
4.
Expert systems are built on knowledge gathered from human experts, analogous to a database but containing rules that may be applied to solving a specific problem. An interface allows the user to specify symptoms and to clarify a problem by responding to questions posed by the system. Software tools exist to help designers build a specialpurpose expert system with minimal effort. An outgrowth of work in artificial intelligence, expert systems show promise for an ever-
AI, or at least the semblance of intelligence, has developed in parallel with computer processing power, which appears to be the main limiting factor. Early AI projects, such as playing chess and solving mathematical problems, are now seen as trivial compared to visual pattern recognition, complex decision making, and the use of natural language.
.
Submitted ToMr.Raman Kumar
Submitted Bymonika mal Roll no.129/04
CASE STUDY OF MYCIN MYCIN is one of the most widely known of all expert system applications developed. And this despite the fact that it has never been put into practice. However, MYCIN is significant to the history of expert/knowledge-based systems for two particular reasons. First, unlike DENDRAL, which used a 7 model of a particular molecule as the basis for its reasoning, MYCIN was constructed from interviews with various doctors in the particular domain. Therefore, MYCIN contains a number of heuristic rules that are used by physicians in the identification of certain infections. The second major contribution of MYCIN was the later development of EMYCIN (Empty MYCIN). EMYCIN was the first expert/knowledge-based system shell. It took approximately 20 man-years to develop the MYCIN program. The researchers realized that if expert systems were to become a viable problem solving technique this development time must be cut. In an effort to do reduce the time to develop an expert system the researchers developed EMYCIN by taking all of the rules out of the system and leaving just an empty “shell” in which other developers in other domains could then just “plug-in” their new knowledge base. One of the best known expert systems is MYCIN (Shortliffe 1976; Davis, Buchanan and Shortliffe 1977), a program for advising physicians on treating bacterial infections of the blood and meningitis. It does reasonably well without common sense, provided the user has common sense and understands the program's limitations. MYCIN conducts a question and answer dialog. After asking basic facts about the patient such as name, sex and age, MYCIN asks about suspected bacterial organisms, suspected sites of infection, the presence of specific symptoms (e.g. fever, headache) relevant to diagnosis, the outcome of laboratory tests, and some others. It then recommends a certain course of antibiotics. While the dialog is in English, MYCIN avoids having to understand freely written English by controlling the dialog. It outputs sentences, but the user types only single words or standard phrases. Its major innovations over many previous expert systems were that it uses measures of uncertainty (not probabilities) for its diagnoses and the fact that it is prepared to explain its reasoning to the physician, so he can decide whether to accept it.
MYCIN begins with its ontology. The ontology of a program is the set of entities that its variables range over. Essentially this is what it can have information about. MYCIN's ontology includes bacteria, symptoms, tests, possible sites of infection, antibiotics and treatments. Doctors, hospitals, illness and death are absent. Even patients are not really part of the ontology, although MYCIN asks for many facts about the specific patient. This is because patients aren't values of variables, and MYCIN never compares the infections of two different patients. It would therefore be difficult to modify MYCIN to learn from its experience. The production formalism turned out to be suitable for representing a large amount of information about the diagnosis and treatment of bacterial infections. When MYCIN is used in its intended manner it scores better than medical students or interns or practicing physicians and on a par with experts in bacterial diseases when the latter are asked to perform in the same way. However, MYCIN has not been put into production use, and the reasons given by experts in the area varied Some said it would be ok if there were a means of keeping MYCIN's database current with new discoveries in the field, i.e. with new tests, new theories, new diagnoses and new antibiotics. For example, MYCIN would have to be told about Legionnaire's disease and the associated Legionnella bacteria which became understood only after MYCIN was finished. (MYCIN is very stubborn about new bacteria, and simply replies ``unrecognized response''.) Others say that MYCIN is not even close to usable except experimentally, because it doesn't know its own limitations. I suppose this is partly a question of whether the doctor using MYCIN is trusted to understand the documentation about its limitations. Programmers always develop the idea that the users of their programs are idiots, so the opinion that doctors aren't smart enough not to be misled by MYCIN's limitations may be at least partly a consequence of this ideology. An example of MYCIN not knowing its limitations can be excited by telling MYCIN that the patient has Cholerae Vibrio in his intestines. MYCIN will cheerfully recommend two weeks of tetracycline and nothing else. Presumably this would indeed kill the bacteria, but most
likely the patient will be dead of cholera long before that. However, the physician will presumably know that the diarrhea has to be treated and look elsewhere for how to do it. On the other hand it may be really true that some measure of common sense is required for usefulness even in this narrow domain. We'll list some areas of common sense knowledge and reasoning ability and also apply the criteria to MYCIN and other hypothetical programs operating in MYCIN's domain.
CASE STUDY OF E-MYCIN GENERIC NAME: erythromycin BRAND NAMES: E-Mycin, Eryc, Ery-Tab, PCE, Pediazole, Ilosone DRUG CLASS AND MECHANISM: Most infections are caused by bacteria that invade and grow in the human body. Medications that control or eradicate these bacteria are called antibiotics. Erythromycin is an antibiotic that prevents bacteria from producing proteins, which interferes with bacterial growth and multiplication, while not affecting human Erythromycin is an antibiotic used to treat many kinds of infections, including: Acute pelvic inflammatory disease Gonorrhea Intestinal parasitic infections Legionnaires' disease Listeriosis Pinkeye Rectal infections Reproductive tract infections Skin infections Syphilis Upper and lower respiratory tract infections Urinary tract infections
Whooping cough Erythromycin is also prescribed to prevent rheumatic fever in people who are allergic to penicillin and sulfa drugs. It is prescribed before colorectal surgery to prevent infection.
Most important fact about this drug Erythromycin, like any other antibiotic, works best when there is a constant amount of drug in the blood. To help keep the drug amount constant, it is important not to miss any doses. Also, it is advisable to take the doses at evenly spaced times around the clock.
Medication Some forms of erythromycin are most effective when taken on an empty stomach. Your doctor may advise you to take each dose at least 1/2 hour and preferably 2 hours before meals. Delayed release formulations may be taken with or without food. Chewable forms of erythromycin should be crushed or chewed before being swallowed. Delayed-release brands and tablets and capsules that are coated to slow their breakdown should be swallowed whole. Do not crush or break. If you are not sure about the form of erythromycin you are taking, ask your pharmacist. The liquid should be shaken well before each use. •
If you miss a dose... Take it as soon as you remember. If it is almost time for your next dose, and you take 2 doses a day, space the missed dose and the next dose 5 to 6 hours apart; if you take 3 or more doses a day, space the missed dose and the next one 2 to 4 hours apart. Never take 2 doses at the same time.
•
Storage instructions... The liquid form of erythromycin should be kept in the
refrigerator; use E.E.S. within 10 days. Do not freeze. Store tablets and capsules at room temperature in a tightly closed container.
side effects Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine whether it is safe to continue taking this medication. •
Side effects may include: Abdominal pain, diarrhea, loss of appetite, nausea, vomiting
Case study of neomycin Generic Name: neomycin (nee oh MY sin) Brand Names: Mycifradin, Neo-Fradin, Neo-Tab Neomycin is an antibiotic. Neomycin is used to reduce the risk of infection during surgery of the bowel. Neomycin is also used to reduce the symptoms of hepatic coma. Neomycin may also be used for purposes other than those listed here. Neomycin may cause damage to the kidneys and/or nerves. Kidney function and drug levels in the blood may be monitored with blood tests during treatment. Tell your doctor if you experience decreased urination, hearing loss, ringing in the ears, feeling of fullness in the ears, dizziness, numbness, skin tingling, muscle twitching, or seizures which may be signs of kidney or nerve damage. Do not take neomycin without first talking to your doctor if you have • • •
kidney disease; a blockage in the intestines; bowel disease such as Crohn's disease or ulcerative colitis;
a neuromuscular disorder such as Parkinson's disease or myasthenia gravis; • hearing loss or loss of balance due to ear problems; or • other medical problems or if you take other medications. You may not be able to take neomycin, or you may require a dosage adjustment or special monitoring during treatment if you have any of the conditions listed above. •
Neomycin side effects If you experience any of the following serious side effects, stop taking neomycin and seek emergency medical attention: • an allergic reaction (shortness of breath; closing of the throat; hives; swelling of the lips, face, or tongue; rash; or fainting); • little or no urine; • decreased hearing, ringing in the ears, or a feeling of fullness in the ears; • dizziness, clumsiness, or unsteadiness; • numbness, skin tingling, muscle twitching, or seizures; or • severe watery diarrhea and abdominal cramps. Other, less serious side effects may be more likely to occur. Continue to take neomycin and talk to your doctor if you experience • nausea or vomiting; or • diarrhea.
DIFFERENCE BETWEEN Artificial intelligence & Expert system
S.NO 1.
ARTIFICIAL INTELLIGENCE The branch of computer science concerned with making computers behave like humans. Artificial intelligence includes: games playing expert systems natural language neural networks robotics
EXPERT SYSTEM A computer application that performs a task that would otherwise be performed by a human expert. For example, there are expert systems that can diagnose human illnesses, make financial forecasts, and schedule routes for delivery vehicles. Some expert systems are designed to take the place of human experts, while others are designed to aid them.
2.
Currently, no computers exhibit full artificial intelligence (that is, are able to simulate human behavior
Expert systems are part of a general category of computer applications known as artificial intelligence
3.
Computer-based system Ability of a machine to perform designed to respond like a tasks thought to require human human expert in a given intelligence field.
4.
Expert systems are built on knowledge gathered from human experts, analogous to a database but containing rules that may be applied to solving a specific problem. An interface allows the user to specify symptoms and to clarify a problem by responding to questions posed by the system. Software tools exist to help designers build a specialpurpose expert system with minimal effort. An outgrowth of work in artificial intelligence, expert systems show promise for an ever-
AI, or at least the semblance of intelligence, has developed in parallel with computer processing power, which appears to be the main limiting factor. Early AI projects, such as playing chess and solving mathematical problems, are now seen as trivial compared to visual pattern recognition, complex decision making, and the use of natural language.
.
