1. سید ضیاء الدین البرزی زیر نظر جناب دکتر حلاوتی

2.  One common methods used for representing knowledge in an expert systems.  How a FB experts system uses frames combined with techniques borrowed from OOP to create powerful tool for addressing complex problems.  Developing a FB system  Collection of related objects that describe the problem.

3.  The motivation for current work in FB expert systems has its roots in earlier human problem-solving studies by cognitive psychologists.  Bartlett (1932)  Schema : is a unit of knowledge that contains info. About some concept  automobile  Following this idea Minsky propose Frame (1975)  Frame : is a data structure for encoding in a computer typical info. On some concept.

4.  Frame = Name + Slots + Values + Procedures  Object Oriented Programming Date :UNKWONDate :1957 Make :UNKWONMake :Chevy ColorUNKWONColorRed Wheels4 4 StartingProcedure 1StartingProcedure 1 CONCEPT  INSTANCE Car  Your Car

5.  A computer program that process problem-specific information contained in working memory with a set of frames contained in the knowledge base, using an inference engine to infer new information.  FB Systems ≡ RB Systems  Relationships between frames is expressed by child-to- parent distinction

6. MenWomen Kathy LucyBobJack Humans Names Values Facets Properties(slots) Class Subclass Instances RulesGoal agenda

7.  A collection of objects that share some common properties. Class nameHumans Sub classMen, Women Properties AgeUnknown Number of legs2 ResidenceUnknown Life expectancy72 Class of Humans

8.  Subclasses are classes that represent subset of higher level classes.  Three kind of relationship among classes and subclasses.  Generalization  Kind of…  Aggregation  Part of…  Association  Semantic…

9.  Generalization BoatPlaneCars Vehicle Kind of

10.  Aggregation Battery EngineDoor Car Part of

11.  Association Assets Houses Cars I own Semantic

12.  Procedures store in Facet  We can add more properties Class namemen Sub class Properties AgeUnknown Number of legs2 ResidenceUnknown MustacheUnknown Class of men

13.  A specific object from a class of objects. Object nameJack Classmen Properties Age40 Number of legs1 ResidencePittsburg MustacheTrue Object jack

14.  The properties used in frames describe the major features or att. Of concept or object.  Properties = Form a set of object-attribute-values  Property values = Data assign to a given property  Values = Numeric, symbolic, boolean. Another feature  facets

15. Object nameRefrigerator ClassHome appliances Properties Age10 Service No.123-1990 LocationPittsburg ConditionGood PowerElectricity Volume16 Refrigerator Object

16.  Inheritance  Process by which the characteristics of parent frame are assume by its child frame  Exception handling  Don’t forget …  Multiple inheritance  Jack is instance of Men & jack is instance of Employee

17.  Extended knowledge about a frame’s property.  Facet extend the info. In  Type  Default  Documentation  Constraint  Minimum cardinality  Maximum cardinality  If needed  If changed

18. Object nameSensor 1 ClassTemperature sensors PropertyReadingUnknown FacetsMin cardinality1 TypeNumeric If-NeededData acquisition If changedChange display Obj. PropertyLocationPump 1 FacetsMin cardinality1 Max cardinality1 If-NeededLocation Image ConstraintPump1, Pump2, Pump3

19.  Methods  A procedure attached to an object, that will be executed whenever requested  (if needed, if changed)  Encapsulation  Hiding of information (use w/o worrying about opration )  Communication between objects  One Obj. use another one when if needed or changed (For example  refrigerator + defrost timer + heating coil)  Message passing

20.  A signal to an object to which the object responds by executing a method.  Ask a request from your friend.  Draw message to a circle obj.  Sometimes named handler.  According to shell  Send, Sendmsg, SendMessage.  (Send message-name object-name arguments)

21. Year 1970 Bobs--Car Args (year) Year 1980 Jacks--Car message Age method 1990 10 20

22.  Inheriting behavior  Bobs-car.year  Writing general methods  Self.property  name to self, object’s property to property.  Rule interaction with objects  Frame properties as Data If Humans.Legs=2 Then Humans can walk If Jack.Legs =2 Then Jack can walk

23.  Modifying a property value  IF jack likes to swim THEN Jack.Sports=Swimming  Creating a New Instance  IF Lucy is mad at jack because he doesn’t like walking THEN MAKE Frame BOB Instance of Humans WITH Sports=walking  Delete an instance  IF Lucy is really mad at Jack THEN RETRACT Frame JACK

24.  Pattern matching  Using matches in rule’s conclusion Frame ?X Instance of Humans WITH Residence=Pittsburg WITH Age= ?Age Frame ?X Instance of Humans WITH Residence=Pittsburg WITH Age= ?Age THEN Age= ?Age +5

25.  Complex variable Matching IF Frame ?person1 WITH Sex=Male WITH Sports = ?Sports1 AND Frame ?Person2 WITH Sex=Female WITH Sports=?Sports1 THEN Frame ?Person1 WITH Likes=?Person2

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