SE-381 Homework 2: Requirements Specification Exercise (Z Model)

Fall quarter 2003-2004

Dr. Mark J. Sebern

Introduction

The purpose of this exercise is to use Z notation to model portions of a software system.

Assignment details

Introduction

This is a team (3-4 members) project; you may not do it as an individual.

This assignment is based on the informal requirements specification exercise completed as homework 1.

Activities

Perform the following activities:

1. Start with the skeleton Z model developed in class.
2. Complete the specification of at least the following operations:
   • FloorAction
   • MoveElevator
   • ChooseDirection

   Use the interface definition implied by each of these operations. However, you may replace the skeleton schema with a schema of the same name defined using the schema calculus (e.g., disjunction), based on partial and supplementary operations. The operation status codes (e.g., StatusOutOfService) are offered as suggestions; you may modify them as you wish.

3. After importing your specification into Z/EVES and checking the syntax, attempt to prove at least the "totality" theorems (that the precondition is met for all possible inputs and states) for each of the above operations. Include the proof steps in a "zproof" section of your LaTeX model file. You will probably have some difficulty with the proofs, so start on them early and ask the instructor for assistance. You may get some ideas by running the proofs that are already provided for other theorems in the skeleton model.
4. Add or edit the informal text of the specification as necessary, so the intent of your Z model can be easily understood.
5. For extra credit, you may add other parts of the elevator system specification. Be sure to supply appropriate informal text and proofs. You may consult the instructor for suggestions. Be sure to label your extra credit content so it is clear what you are claiming.
6. Add a section to your specification describing any observations on the assignment, difficulties you encountered, or questions that you still have.

Report

Your report should consist of the following:

• The LaTeX (".tex") specification source file; name it Name1Name2Name3Name4HW3.tex, where NameX is the last name (NOT username) of each team member.
• The PDF document you created from it; name it Name1Name2Name3Name4HW3.pdf.

The report is due before class on the day specified in the course schedule.

If you have questions about the assignment, please consult the instructor (in person or by email) as soon as possible.

Submit your report files using WebCT (it will allow you to submit separate files). Be sure to keep your own copy for safekeeping.

This page was last updated on Tuesday, 28-Oct-2003 07:09:22 CST.

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