Chapter 8: Building a Knowledge Base
Five step of Knowledge Engineering :
(use circuit design as an example)
1.Decide what to talk about.
Example :
Circuit, Terminal, Signal, Gate, Gate-Type (AND, OR ..)
2.Decide on a vocabulary of predicates, functions and constants
Example :
Gate Name : Gate (X1, X2, .. ..)
Type Function : Type(X1), Type(X2).. ..
Input Predicate : IN(1, X1), IN(2, X2) .. ..
3.Encode general knowledge about the domain.
Example :
Connected(t1, t2)=>Signal(t1)=Signal(t2) （同線等電位）
Signal(t)=On | Signal(t)=Off (不是on就是 Off)
Type(g)=OR => Signal(Out(1,g))=On <=> Signal(Out(1,g))=Off
(OR gate的作用)
4.Encode a description of the specific problem instance.
Example :
設計一個加法器。
5.Pose queries to the inference procedure and get answers.
Example :
Circuit verification, 用testing case測試是否正確。
本體論(一般型態) General Ontology
1. 分類 Categories :
By Unary Predicate : Tomato(x) ,
By reification : turning a predicate into an object ,
Tomatos, is(x, Tomatos)
Disjoint({Animals, Vegetables})
ExhaustiveDecompisition({American, Canadians, Mexicans},NorthAmericans)
Partition({Males, Females}, Animals)
2. 度量 Measures :
Unit function :
Length(L1)=Inches(1.5)=Centimeters(3.81)
Order is important :
Exercise(e1)&Exercise(e2)&(Difficulty(e1)>Difficult(e2))
=> ExpectedScore(e1)<ExpectedScore(e2)
3. 組合 Composite objects :
PartOf(Bucharest, Romania)
Schema , script :
PartPartition({head, body, hand, leg}, person)
BunchOf({Apple1, Apple2, Apple3})
4. 時空改變 Time, Space, and Change :
5. 事件與過程 Events and Processes :
Situation calculus的不足：
1. 無法描述連續時間
2. 無法描述 Multiple Agent.
Event calculus : (situation calculus in continuous version)
An Event is just a “chunk” of this universe with both temporal and spatial extent.
Time Example : SubEvent(BattleOfBritian, WorldWarII)
SubEvent(WorldWarII, TwentiethCentury)
Place Example: In(NewYork, USA)
Minimization : (描述最小區域或最小時段)
Example: Loaction(x)=l <=> At(x,l)&$At(x,l2)=>In(l,l2)
Process (liquid event categories):
Event(Flying(Johnson, Yesterday))
Throughout(Working(Johnson),TodayLunchHour)
Throughout(Closed(Supermarket1), BunchOf(Sundays))
Throughout(p&q,e) Throughout(p|q, e) Throughout(p xor q,e)
---------------- --- ---
---------------- -------------- -- ---
Interval(i)=>(Moment(i)<=>Duration(I)=0)
Interval(i)=>Duration(i)=(Time(End(i))-Time(Start(i)))
Meet(i,j)<=> Time(End(I))=Time(Start(j))
Before(i,j)<=> Time(End(I))<Time(End(j))
After(j,i)<=> Before(i,j)
During(i,j)<=> Time(Start(j))<=Time(Start(I))&Time(End(I)<=Time(End(j)))
Overlap(i,j)<= > #k During(k,i)&During(k,j)
Meet(i,j) i: -----------
j: --------------
Before(i,j) i: --------
j: --------------
During(i,j) i: --------
j: --------------
Overlap(i,j) i: --------------
j: --------------
6. 實體 Physical Objects :
Typical典型 : Typical(C) is subset of C :
若無特別指定（例外），則x in C => x in Typical(C)
Fluents Object 會隨時間改變的實體(temporal substance):
example : President(USA)
individuation 不可分割的實體 :
example : People
7. 物質 Substances :
可分割的實體stuff (spatial substance) (example : Butter)
Butter&PartOf(y,x)=>Is(y,Butter)
8. 精神、信仰 Mental Objects and Beliefs
Believes(Agent,x) : x is referential opaque
example :
Superman=Clark ╞ (Believes(Lois, Flies(Superman))<=>
(Believes(Louis,Flies(Clarkis)))
is not right.
Referential transparency :
The property of begin able to freely substitute a term for an equal
term is called referential transparency.
Syntactic theory : Flies(clark) => [F,l,i,e,s,(,C,l,a,r,k,)]
Semantic :
Denote(“Clark”)=ManOfSteel&Denote(“Superman”)=ManOfSteel
Name(ManOfSteel)=”K11”
Proof Theory :
LogicalAgent(a)&Believes(a,p)&Believes(a,”p=>q”)=>Believes(a,q)
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