95-843 Service Oriented Architecture          Homework 1

Due: Midnight, Tuesday evening, October 28, 2008

Fundamental Issues
==================

Please review the chapter on Petri nets from the Johnsonbaugh
text (PetriNetIntro.pdf)  and read the article by Hamadi on web 
service composition using Petri nets. Both of these are provided on the 
course schedule.

Submit a Word document or scanned drawings containing your 
answers to the digital drop box on blackboard.

Model the following algorithms with a Petri net. Provide a 
marking that represents the situation prior to execution of
the algorithm.

1. A = 1
   B = 2
   C = A + B
   C = C + 1

2. A = 2
   B = A + A
   C = 3
   D = A + A
   C = A + B + C

3.     A = 1
       S = 0
   10  S = S + A
       A = A + 1
       GOTO 10

4. Wash a lion:

   1. Get lion.
   2. Get soap. (real soap not SOAP)
   3. Get tub.
   4. Put water in tub.
   5. Put lion in tub.
   6. Wash lion with soap.
   7. Rinse lion.
   8. Remove lion from tub.
   9. Dry lion.

5. Describe the following web service in words: 
   Ref(S1, assess_claim, [A1:An])

6. Prove statement (20) of the Service Algebra studied in class.

7. Prove statement (21) of the Service Algebra studied in class.