Expert system Presented by Tahir Abbas

Abdual Wahab Ayesha Liaqat Munnaza Iqbal Kiran Masroor

Expert system Expert system is a computer program that contains

some of the subject specific knowledge of one or more human experts.

These are complex AI programs Expert systems are generally software's

HISTORY OF EXPERT SYSTEM

Purpose of ES

To make a program intelligent, provide it with lots of high quality, specific knowledge about some problem of specific area

To clarify all the uncertainties come in system

PERFORMANCE OF ES Performance of expert system based on following method KNOWLEDGE ENGENEERING 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.

Building blocks of ES

Every expert system consist of two principal parts:

(a) Knowledge base

(b) Reasoning or inference

Knowledge base

It 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.

Reasoning

Two 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.

APPLICATIONS OF ES

Its applications spread in a wide range i.e. in industrial and commercial problems etc.

Diagnosis and troubleshooting of devices and system of all kinds Planning and scheduling Configuration of manufactured objects Financial decision making Knowledge publishing Process monitoring and control

ADVANTAGES OF ES

COSISTENT: it provides consistent answer for repetitive decisions, processes and tasks

MAINTAINS: it holds and maintain levels of information

CLARIFY: it clarify the logic of decision making

NO HUMAN NEED: it cannot needs human, it works continuously

MULTIUSER: a multi user expert system can serve more users at a time

DISADVANTAGES OF ES

SENSE: it lacks common sense needed in decision making

CREATIVENESS: it cannot respond creatively like a human expert would in unusual circumstances

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

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

APPLICATIONS OF ES IN DIFFERENT FIELDS

In medical field

In agricultural

In education etc.

IN MEDICAL FIELD (EXAMPLE) (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:

The knowledge base

The explanation interface

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) CaDet It 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) DXplain It is used for diagnosis.

Its data based contain approximately 4,500 suggestion for over 2,000 different diseases.

(4) MYCIN It 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) GERMWATCHER It is for infection control.

Agricultural ES (Examples) 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

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 SYSTEM

NAMES OF SOME OTHER EXPERT SYSTEMS:

CLIPS

GIS

LEY

CALEX

EXPERT SYSTEMS IN EDUCATION

IN EDUCATIONFIELDS:

Computer animation

Computer science

Engineering

Language (expert system teaches language)