INTRODUCTIONAI programs that achieve expert level competence

(ability) in solving problems in particular task area by use of knowledge base about that particular task area are known as KNOWLEDGE BASED OR EXPERT SYSTEMS.

These are complex AI programs.Expert systems are generally software's.These software helps us to provide an answer to a

problem.It helps to clarify uncertainties that comes in system.

TASK-DOMAINThe human intellectual (requiring the use of mind) trying

to be captured in an expert system is called the task domain.

TASK—means some goal oriented, problem solving activity.

DOMAIN—means area within which the task is being performed.

PERFORMANCE Performance of the expert system is based on following

methods:-Knowledge engineering:-Building an expert system is known as KNOWLEDGE

ENGINEERING. In this knowledge gathers from subject matter experts and

then codifying this knowledge according to the formalism.Persons doing this are called KNOWLEDGE

ENGINEER.

COMPONENTS OF EXPERT SYSTEMSBUILIDING BLOCKS OF EXPERT SYSTEM:-Every expert system consist of two principal parts: (a) Knowledge base (b) Reasoning or inference

Knowledge baseIt is expert systems contain both factual and

heuristic knowledge.Factual knowledge is that knowledge of task

domain that is widely shared, typically found in textbooks or journals.

Heuristic knowledge is less exhaustive, more experiential, more judgmental knowledge of performance.

ReasoningTwo methods of reasoning when using inference

rules: (i) Backward chaining: it starts with list of goals and

works backward if there is data which will allow it to conclude these goals.

(ii) Forward chaining: it starts with data available and then concludes a desired goal.

THE APPLICATION OF EXPERT SYSTEMSIts applications spread in a wide range i.e. in industrial and

commercial problems etc.1. Diagnosis and troubleshooting of devices and system of all

kinds2. Planning and scheduling3. Configuration of manufactured objects4. Financial decision making5. Knowledge publishing6. Process monitoring and control

ADVANTAGES1. COSISTENT: it provides consistent answer for

repetitive decisions, processes and tasks2. MAINTAINS: it holds and maintain levels of

information3. CLARIFY: it clarify the logic of decision making4. NO HUMAN NEED: it cannot needs human, it

works continuously5. MULTIUSER: a multi user expert system can serve

more users at a time

DIS-ADVANTAGES1. SENSE: it lacks common sense needed

in decision making2. CREATIVENESS: it cannot respond

creatively like a human expert would in unusual circumstances

3. ERRORS: in knowledge base errors may occur and this leads wrong decisions

4. ENVIRONMENTS: if knowledge base is changed it cannot adapt changing environments

USES OF EXPERT SYSTEMS1. In medical field2. In agricultural 3. In education etc.

IN MEDICAL FIELD

EXAMPLES OF ES IN MEDICAL (1) PXDES It is example of medical expert system. It is a lung disease, X-ray diagnosis. It takes our lungs picture from upper side of body which looks like a shadow. The shadow is used to determine the type and degree of harmness. These systems include three modes:1. The knowledge base2. The explanation interface3. The knowledge acquisition(1) KNOWLEDGE BASE:- It contains the data of X-ray representations of various stages of the disease. (2) EXPLANATION INTERFACE:- It details the conclusion.(3) KNOWLEDGE ACQUISITION:- It allow medical experts to add or change information in the system.

(2) CaDetIt is for early cancer detection.Clinical data related to early cancer detection and to

cancer risk factors was collected and incorporated in database, together with heuristic rules for evaluating this data.

(3) DXplainIt is used for diagnosis.Its data based contain approximately 4,500 suggestion for

over 2,000 different diseases.

(4) MYCINIt is simple example of ES.It performs a task normally done by a human expert.It attempts to recommend appropriate therapies for patient

with bacterial infections.It uses LISP structures for writing internally rules.It uses these rules to reason backward to the clinical data

available from its goal of finding disease-causing organism.

(5) GERMWATCHERIt is for infection control.

AGRICULTURAL EXPERT SYSTEMSWHY?It is same as other knowledge based systems.It uses to give answer about pest control, the need to

spray, selection of a chemical to spray, weather damage recovery such as freeze etc.

ARICULTURAL EXPERT SYSTEM(1) RICE-CROP DOCTOR: This ES is developed by NATIONAL INSTITUTE OF AGRICULTURAL EXTENSION

MANAGEMENT. Its main work is to diagnose pests and diseases for rice crop and suggest preventive measures. It has knowledge about diseases and pests for identification and suggesting preventive measures.(1) DISEASES: Rice blast Brown spots Rice tungro virus Bacterial leaf blight etc(2) PESTS: Stem borers Brown plant hopper Rice leaf folder Green leaf hopper etc

AGRICULTURAL EXPERT SYSTEM(2) AGREX:It gives correct advice to farmers.Topics of advice are fertilizer application, crop protection,

irrigation scheduling and diagnosis of diseases in paddy and post harvest technology of fruits and vegetables

AGRICULTURAL EXPERT SYSTEMNAMES OF SOME OTHER EXPERT SYSTEMS:CLIPSGISLEYCALEX

AGRICULTURAL EXPERT SYSTEMADVANTAGES:-1. It has ability to imitate human thought and reasoning.2. It makes modification of knowledge very convenient.3. It helps increases the production of crops4. It has ability to handle uncertain information5. It helps the farmers to take single point decision.

EXPERT SYSTEMS IN EDUCATIONWHY?Because it allow users to ask question on some education

problems.

IN EDUCATIONFIELDS:Computer animationComputer scienceEngineeringLanguage (expert system teaches language)

IN EDUCATIONThis figure shows the architecture of ITS for teaching

engineering student which has embedded expert system inside.

For each student expert system will create performance of student and change levels (like easy to difficult).