1 Team Skill 1 - Analyzing the Problem (Chapters 5-7 of the requirements text) CSSE 371, Software Requirements and Specification Don Bagert, Rose-Hulman Institute of Technology September 6, 2005 Thanks to Mark Ardis for some of the slides included.

2 Outline  The Five steps in problem analysis  Business modeling  System engineering issues

3 The Five Steps in Problem Analysis 1.Gain agreement on the problem 2.Understand the root causes 3.Identify the stakeholders 4.Define the solution system boundary 5.Identify the constraints imposed on the solution

4 Step 1: Agree on the Problem  Write the problem statement A problem statement is the problem to be solved, written in a standardized format

5 One Format for Problem Statements  Function: What the solution must do and how it will be used  Form: The form the system must take in providing the functional features  Economy: The expected value and cost of the solution to customers and to your own organization  Time: The relationship of the solution to past, present, and future

6 Step 2: Find Root Causes  One method: Fishbone or Ishikawa (Kaoru Ishikawa) diagrams 1.Place problem in head of fish 2.Draw major bones for different aspects or viewpoints 3.Draw causes as smaller bones (recursively)

7 An Example Fishbone Diagram Lousy Meals Same old every day Lousy cooks Too far from suppliers Lousy kitchen Poor education Poor attitude Have to get up early Underpaid

8 Step 3: Identify Stakeholders  Who are the users?  Who is the customer?  Who else will be affected?  Who will approve the system?  Who will maintain the system?  Who else cares?

A Typical Stakeholder Buffy the Vampire Slayer. Source: Warner Brothers

10 Step 4: Define Boundaries  Draw a picture: Solution system is a black box in the middle of the picture Users of the software are shown Systems that interact with the solution are also shown These users and interacting systems are collectively known as “actors”

11 Here Are Some Actors Source: Rose-Hulman Drama Club website

Actors Can Also Be Something Rather Than Someone Source: clipart.com

13 Step 5: Identify Constraints Frequently-Used Constraint Classifications Economics Politics Technology Existing Systems Environment Schedule and Resources

14 Two Domain-Specific Problem Analysis Techniques  Business Modeling Information Systems/IT domain  Systems Engineering Embedded systems domain