Development of Our Simple Expert System

Below is the development of our simple expert system!!!
To see it, please click this FILE !!!

Looping in Prolog

Loops
Sebagian besar bahasa pemrograman mempunyai fasilitas looping. Akan tetapi, fasilitas ini tidak terdapat di prolog. Sebagai penggantinya, kita dapat menggunakan backtracking, rekursi, built-in predikat, atau mengkomninasikannya.

Looping a Fixed Number of Times
Dalam prolog tidak ada fasilitas ‘for loops’ sebagaimana bahasa pemrograman lain. Sebagai penggantinya, kita dapat menggunakan rekursi.
Contoh :
Program ini mengeluarkan bilangan bulat mulai dari angka yang dimasukkan hingga 1.
Notepad :
loop(0).
loop(N):-N>0,write('The value is: '),write(N),nl,
M is N-1,loop(M).

Prolog :
?- loop(6).
The value is: 6
The value is: 5
The value is: 4
The value is: 3
The value is: 2
The value is: 1
yes

Looping Until a Condition Is Satisfied

Dalam prolog tidak ada fasilitas ‘until loops’ sebagaimana bahasa pemrograman lain. Sebagai penggantinya, kita dapat menggunakan :
1. Rekursi
Contoh :
Notepad :
go:-loop(start). /* start is a dummy value used to get
the looping process started.*/
loop(end).
loop(X):-X\=end,write('Type end to end'),read(Word),
write('Input was '),write(Word),nl,loop(Word).

Prolog :
?- go.
Type end to end: university.
Input was university
Type end to end: of.
Input was of
Type end to end: portsmouth.
Input was portsmouth
Type end to end: end.
Input was end
Yes

2. ‘Repeat’ predikat
Contoh :
Notepad :
get_answer(Ans):-
write('Enter answer to question'),nl,
repeat,write('answer yes or no'),read(Ans),
valid(Ans),write('Answer is '),write(Ans),nl.
valid(yes). valid(no).

Prolog :
?- get_answer(X).
Enter answer to question
answer yes or no: unsure.
answer yes or no: possibly.
answer yes or no: no.
answer is no
X = no

Backtracking with Failure

Berikut adalah fungsi-fungsi backtracking dalam prolog.
1. Mencari database prolog
Contoh :
Notepad :
dog(fido).
dog(fred).
dog(jonathan).

alldogs:-dog(X),write(X),write(' is a dog'),nl,fail.
alldogs.

Prolog :
?-alldogs
fido is a dog
fred is a dog
jonathan is a dog
yes
2. Menemukan solusi ganda
Contoh :
find_all_routes(Town1,Town2):-
findroute(Town1,Town2,Route),
write('Possible route: '),write(Route),nl,fail.
find_all_routes(_,_).

Looping in Prolog

Below is tutorial to learn looping in prolog :
Please click this file
thank you :)

INPUT and OUTPUT in Prolog

Input and Output

Outputting Terms
Output form that be used in prolog is write/1 dan nl/0 predicate. Evaluating the predicate write/1 causes the term to be written to the current output stream and evaluating a nl goal causes a new line to be output to the current output stream.
Examples :
?- write('Example of use of nl'),nl,nl,write('end of example'),nl.
Example of use of nl
end of example
yes
if we want to show atoms, we can use writeq/1.
Examples :
?- writeq('a string of characters'),nl.
'a string of characters'
yes

Inputting Terms
Input form that be used in prolog is read/1. Evaluating it causes the next term to be read from the current input stream. In the input stream, the term must be followed by a dot ('.') and at least one white space character, such as space or newline. The dot and white space characters are read in but are not considered part of the term.
Example :
?- read(Z).
: [a,b,mypred(p,q,r),[z,y,x]].
Z = [a,b,mypred(p,q,r),[z,y,x]]
?- read(Y).
: 'a string of characters'.
Y = 'a string of characters'
?- X=fred,read(X).
: jim.
no
?- X=fred,read(X).
: fred.
X = fred

Input and Output Using Characters
There are many characters that can be used in input and output using prolog. All printing characters and many non-printing characters have a corresponding ASCII (American Standard Code for Information Interchange) value, which is an integer from 0 to 255.
The table below gives the numerical ASCII values corresponding to the main printable characters and some others.

9 : tab
10 : end of record
32 : space
33 : !
34 : "
35 : #
36 : $
37 : %
38 : &
39 : '
40 : (
41 : )
42 : *
43 : +
44 : ,
45 : -
46 : .
47 : /
48-57 : 0 to 9
58 : :
59 : ;
60 : <
61 : =
62 : >
63 : ?
64 : @
65 : -
90 : A to Z
91 : [
92 : \
93 : ]
94 : ^
95 : _
96 : `
97 : -
122 : a to z
123 :{
124 : |
125 : }
126 : ~
Characters whose ASCII value is less than or equal to 32 are known as white space characters.

Outputting Characters
Predicate that be used for output characters is put/1 which must be a number from 0 to 255 or an expression that evaluates to an integer in that range. Evaluating a put goal causes a single character to be output to the current
output stream.
Example :
?- put(97),nl.
a

Inputting Characters
Predicate that be used for input a single character are get0/1 and get/1. Evaluating a get0 goal causes a character to be read from the current input stream and evaluating a get goal causes the next non-white-space character to be read from the current input stream.
Example :
?- get0(N).
: a
N = 97
?- M is 41,get0(M).
: )
M = 41
?- M=dog,get0(M).
: )
No
?- get(X).
: Z
X = 90

Using Characters: Examples
The predicate readin is defined recursively. It causes a single character to be input and variable X to be bound to its ASCII value. The action taken (the process(X) goal) depends on whether or not X has the value 42 signifying a * character. If it has, the evaluation of the goal stops. If not, the value of X is output, followed by a new line, followed by a further call to readin. This process goes on indefinitely until a * character is read.
Example :
readin:-get0(X),process(X).
process(42).
process(X):-X=\=42,write(X),nl,readin.
?- readin.
: Prolog Example*
80
114
111
108
111
103
32
69
120
97
109
112
108
101
yes
The ASCII values of the input characters are not output, but the number of characters (excluding the *) is output.
The count predicate is defined with two arguments which can be read as 'the number of characters counted so far' and 'the total number of characters before the *'.
Example :
go(Total):-count(0,Total).
count(Oldcount,Result):-
get0(X),process(X,Oldcount,Result).
process(42,Oldcount,Oldcount).
process(X,Oldcount,Result):-
X=\=42,New is Oldcount+1,count(New,Result).
?- go(T).
: The time has come the walrus said*
T = 33
?- go(T).
: *
T = 0
Predicate vowel tests for one of the 10 possible vowels (five upper case and five lower case), using their ASCII values.
go(Vowels):-count(0,Vowels).
count(Oldvowels,Totvowels):-
get0(X),process(X,Oldvowels,Totvowels).
process(42,Oldvowels,Oldvowels).
process(X,Oldvowels,Totalvowels):-
X=\=42,processChar(X,Oldvowels,New),
count(New,Totalvowels).
processChar(X,Oldvowels,New):-vowel(X),
New is Oldvowels+1.
processChar(X,Oldvowels,Oldvowels).
vowel(65). /* A */
vowel(69). /* E */
vowel(73). /* I */
vowel(79). /* O */
vowel(85). /* U */
vowel(97). /* a */
vowel(101). /* e */
vowel(105). /* i */
vowel(111). /* o */
vowel(117). /* u */
?- go(Vowels).
: In the beginning was the word*
Vowels = 8
?- go(Vowels).
: pqrst*
Vowels = 0

Input and Output Using File
Prolog doing input and output in current stream form. The user may open and close input and output streams with any number of named files but there can only be one current input and output stream.

File Output: Changing the Current Output Stream
The current output stream can be changed using the tell/1 predicate. This value can be restored either by using the told/0 predicate or by tell(user).

File Input: Changing the Current Input Stream
The current input stream can be changed using the see/1 predicate which representing a file name, e.g. see('myfile.txt'). This value can be restored either by using the seen predicate or by see(user).

1. Reading from Files: End of File
If the end of file is encountered when evaluating the goal read(X), variable X will be bound to the atom end_of_file. If the end of file is encountered while evaluating the goal get(X) or get0(X), variable X will be bound to a 'special' numerical value.
2. Reading from Files: End of Record
Typically the end of a line of input at the user's terminal will be indicated by the character with ASCII value 13. The end of a record in a file will generally be indicated by two ASCII values: 13 followed by 10.
readline:-get0(X),process(X).
process(13).
process(X):-X=\=13,put(X),nl,readline.
?- readline.
: Prolog test
P
r
o
l
o
g
t
e
s
t
yes

Expert System for Fixing Dress Color with Skin Color

Expert System for Fixing Dress Color with Skin Color
Background of the Problem
We choose this problem because we want to help people in the choosing dress color that suitable with skin color. We still often look people who wear dress that very not suitable with their skin color so they are looked so weird. For example, people whose skin color is black wear dress whose color is yellow light or red light. Because of that, with this expert system, we hope people not difficult in deciding dress color that must be wore again.
Detail Explanation of Idea
Expert System that we make consist of facts that is many kind of skin color and dress color possibilities that suitable for that skin solor.
We categories kind skin color’s facts to many groups, such as :
1. Hitam
2. Sawo matang
3. Kuning langsat
4. Putih
The possibilities of dress color that suitable with skin color is :
1. Hitam :
- White
- Pink
- Khaki
- Grey
- Baby blue
- Creme
2. Sawo matang
- Black
- Pink
- Burgundy
- Beige
- Navy
3. Kuning langsat
- Black
- White
- Pink
- Red
- Yellow
- Orange
- Grey
- Green
- blue sky
- Crème
- Brown
- Off white
- Beige
4. Putih
- Off white
- Brown
- Blue sky
- Beige
- Bold blue
- Black
- Pink
- Red
- Yellow
- Orange
- Grey
- Green

Beneficial
The benefit that that can be gotten of this Expert System are :
1. Help people to choose the suitable dress color.
2. Make people feel comfort with their dress that is wore.
3. Help people to increase their confidence.

Operator and Arithmetic

Our problem today is :
Practical Exercise 4
(1) This program is based on Animals Program 3, given in Chapter 2.
dog(fido). large(fido).
cat(mary). large(mary).
dog(rover). small(rover).
cat(jane). small(jane).
dog(tom). small(tom).
cat(harry).
dog(fred). large(fred).
cat(henry). large(henry).
cat(bill).
cat(steve). large(steve).
large(jim).
large(mike).
large_dog(X):- dog(X),large(X).
small_animal(A):- dog(A),small(A).
small_animal(B):- cat(B),small(B).
chases(X,Y):-
large_dog(X),small_animal(Y),
write(X),write(' chases '),write(Y),nl.

Convert the seven predicates used to operator form and test your revised program.
The output should be the same as the output from the program above. Include
directives to define the operators in your program.


(2) Define and test a predicate which takes two arguments, both numbers, and
calculates and outputs the following values: (a) their average, (b) the square root of
their product and (c) the larger of (a) and (b).

We make tutorial for number 1 in Engkish and number 2 in Bahasa Indonesia. But we aren't write our tutorial about this problem on this page. You can download it by clicking this FILE!!!

Operators and Arithmetics in Prolog

Operators and Arithmetics
Operators
Up to now, Prolog user usually use the notation for predicates by a number of arguments in parentheses.
Ex : likes(john,mary)
There is another alternative :
- Two arguments (a binary predicates) be converted to an infix operator
the functor be written between two arguments with no parentheses
Ex : john likes mary
- One argument (a unary predicate) be converted to :
1. Prefix operator  the functor be written before the argument with no parentheses
Ex : isa_dog fred
2. Postfix operator  the functor be written after the argument
Ex : fred isa_dog
Both of predicate (one or two arguments) can be converted to an operator by entering a goal using the op predicate at the system prompt. Ex :
?-op(150,xfy,likes).
This predicate takes three arguments :
1. 150 (operator precedence) : an integer from 0 upwards
So we can change it with another integer.
2. Xfy : the predicate is binary and is to be converted to an infix operator.
This argument should normally be one of the following three atoms:
1. Xfy
2. Fy : the predicate is unary and is to be converted to an prefix operator
3. Xf : the predicate is unary and is to be converted to a postfix operator
3. Likes : the name of the predicate that is to be converted to an operator.
Arithmetics
Prolog user can doing arithmetic calculate with prolog, such as :
1. Arithmetic operator
X+Y : sum of X and Y
X-Y : dfference of X and Y
X*Y : product of X and Y
X/Y : quotient of X and Y
X//Y : the ‘integer quotient’ of X and Y (the result is truncated to the nearest integerbetween it and zero)
X^Y : X to the power of Y
-X : negative of X
abs(X) : absolute value of X
sin(X) : sine of X
cos(X) : cosine of X
max(X,Y) : yhe larger of X and Y
sqrt(X) : square root of X
2. Operator presedence in arithmetic expression
Prolog use ordinary algebra algorithm in arithmetic operation.
Ex : A+B*C-D
In the algebra, C*B are calculate first, then the result+A, then the result of sum-D. it is same with those in prolog. But, if we want to calculate A+B, C-D, then multiply both of the result, we must add the parentheses.
Ex : (A+B)*(C-D)
3. Relasion operator
The operator like =,!=, >, >=, <, <= can be used in prolog

Degree operator
Under is the rist of equality operators that used in prolog with the function of each operator:
• Arithmetic Expression Equality ( =:= )
• Arithmetic Expression Inequality ( =\= )
• Terms Identical ( == )
• Terms Not Identical ( \== )
• Terms Identical With Unification ( = )
• Non-Unification Between Two Terms( \= )

Logic operator
a. Operator NOT
Operator not can be placed before predicate to give the negation. Predicate that be negation has the truth value if the origin predicate is false and has the false value if the origin predicate is truth.
The example of using operator not :
dog(fido).
?- not dog(fido).
no
?- dog(fred).
no
?- not dog(fred).
Yes
b. Disjunction operator
Disjunction operator is used as operator ‘atau’.
Ex :
?- 6<3;7 is 5+2.
yes
?- 6*6=:=36;10=8+3.
yes