95-843 Service Oriented Architecture Homework 1
Assigned: Tuesday, March 19, 2013 Due: Tuesday, March 26, 2013
Ten Questions in preparation for the first exam.
These will be marked and returned but not graded.
Fundamental Issues
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Read the chapter on Petri nets from the Johnsonbaugh
text (PetriNetIntro.pdf) and read the article by Hamadi on web
service composition using Petri nets. Read the BPMN slides from
IBM. Watch the four short videos on BPMN. All of these are
provided on the course schedule.
Paper submission: Submit a Word document or drawings containing
your answers on paper during class on Tuesday.
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. In class we described a set theoretic description
of Petri nets. Represent the Petri net you drew
in question 4 (Washing the lion) using sets. Show
the sets P, T and E as on slide 24 of the Introductory
slides.
6. Describe the following web service in words:
Ref(S1, assess_claim, [A1:An])
7. Prove statement (20) of the Service Algebra studied in class.
8. Prove statement (21) of the Service Algebra studied in class.
9. Wash the lion again. This time use the Business Process Modeling
Notation as described on the slides from IBM. Be sure to exploit
parallel execution where possible.
10. a. Consider the Expense Reimbursement Process on slide 76 of IBM's
BPMN slides. Briefly describe where the diagram uses parallelism.
b. In the video BPMN Tutorial - Part 2 - Collaborations, two pools are
used. What is each pool used to represent.
c. In the video BPMN Tutorial - Part 2 - Collaborations, several different
types of BPMN "events" are used. List each event type.
d. Describe the use of BPMN gateways in the video BPMN Tutorial - Part 2 -
Collaborations.