Apr 1999 CO230: Cognitive Science (Question 2)

(a)	Describe four symbolic knowledge models.	[8]
	Clustering model This model stores related concepts or words in clusters or sets, without considering other properties of the concepts. E.g the set of birds. Set-theoretical model This model extends the clustering model by storing not just related concepts, but their defining attributes as well. E.g. The set of birds and the attributes of wings is stored together with the set. Semantic-feature model This extends the set-theoretical model by including not just the defining attributes that determine membership in a category, but any characterisitcs features as well. E.g In addition to the set of birds that has he attribute wings, an ostrich has the characteristic feature of being the largest bird. Network model This model knowledge as a set of logical proposition, sematically related concepts are connected in a network such that when one concept is ativated, all related concepts are primed, easing retrieval.
(b)	Given that Adam is guilty of a crime; and Adam is not in jail, state the truth values of the following propositions:
	(i) Either Adam is guilty of a crime or Adam is in jail.	[1]
	True
	(ii) If Adam is guilty of a crime then Adam is in jail.	[1]
	False
	(iii) Adam is guilty of a crime is equivalent to Adam is in jail.	[1]
	False
(c)	Given that e is the symbol used to represent that the exam was easy; s is the symbol used to represent that Adam studied hard; p is the symbol used to represent that Adam passed the exam; l is the symbol used to represent that Adam was lucky; and c is the symbol used to represent that Adam was found cheating, rewrite the following statements using symbolic representations of propositional logic:
	(i) If the exam was easy or Adam studied hard, then Adam passed the exam.	[1]
	[ ( e v s ) ® p ]
	(ii) If the exam was not easy and Adam studied hard, then Adam passed the exam.	[1]
	[ ( ~e v s ) ® p ]
	(iii) If the exam was easy and Adam was unlucky or the exam was not easy or Adam did not study hard, then Adam would not pass the exam.	[1]
	[ ( (e v ~1 ) v ~e v ~s ) ® ~p ]
(d)	Given that good_dog(fido) means that fido is a good dog; master(ben,fido) means that ben is the master of fido; location(ben,beach) means that ben is at the beach; and well_trained(fido) means that fido is well trained, rewrite the following statements using predicate representation:
	(i) If ben is the master of fido and ben is at the beach, then fido is also at the beach.	[2]
	[ (master (ben, fido ) _^ location (ben, bench ) ) ® location (fido, beach)
	(ii) If ben is the master of fido, then fido will be in the same location as ben.	[2]
	"Z : { places } ( (master (ben, fido ) _^ location (ben, X ) ) ® location (fido, X)
	(iii) If a dog is a good dog and has a master, then it would be in the same location as its master.	[2]
	"X : { humans } "Y : { dogs } "Z : { places } ( (good_dog ( Y ) _^ master (X, Y) _^ location (X, Z ) ) ® location (Y, Z ))