Software Model Clashes

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Software Model Clashes Software Engineering
I, Fall 2003 Ashish Soni
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Outline

• Overview
• Identification of Model Clashes
• Approach
• Examples
• Relationship of Model Clashes to Risk

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Overview

• Problem
• Currently, many software models exist
• Each model is based on certain assumptions
• Many software projects embrace models with
  conflicting assumptions and get into trouble
• Little information exist about the problem of
  model clashes

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Examples of Software Models
Success Models

• Win-Win Business Case Analysis
• Software Warranties QFD
• 10X Six Sigma
• Award Fees . IKIWISI
• JAD

Process Models
Product Models

• UML
• CORBA COM
• Requirements
• Architectures
• Product Lines
• OO Analysis Design
• Domain Ontologies
• COTS GOTS

• Spiral
• Waterfall
• Open Source
• Business Process Reengineering
• CMMs Peopleware
• IPTs Agile
• Evolutionary

• COCOMO
• COCOTS
• Checkpoint
• System Dynamics . Metrics . ilities
• Simulation and Modeling . Environment

Property Models

• Some model assumptions conflict

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Definitions
Assumption An assumption is a statement that
describes a certain attribute of a software
model Model A model is a collection of
assumptions Example Model
Waterfall Attribute Requirements
Completeness Assumption Developer defines and
documents a complete set of requirements for each
system capability before starting the systems
detail design DOD-STD 2167
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Definitions
Model Clash A model clash is a conflict among
the assumptions of the set of the software models
used by the stakeholders to develop the software
product
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Model Assumptions Identification Approach
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Model Assumptions Identification Approach
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Model-Clash Example
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Model Clash Example
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Classification of Models Based on Assumptions
Conflicts

• Models in left column will clash with models in
  right column

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Relationship between Model Clashes and Risk

• Risk Pair ltProbability of loss, Size of lossgt
  answers
• What is the likelihood that unsatisfactory
  outcome will occur?
• If unsatisfactory outcome occurs, what is the
  measure of loss?
• These determine the Risk Exposure P(loss)
  S(loss)
• Model-Clash Pair ltOccurrence Probability,
  Severitygt?

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Determining Model Clashes Occurrence Probability
Severity Approach
CeBASE Data Base
Fall2000-Spring2002
Projects (35)
Weekly Progress
Reports
Project
Top 10 Risks
Assumptions
Model Clashes (61)
Models
Stakeholders
Frequency
Severity
Occurrence Probability
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Model Clashes Occurrence Probability Severity
Example
S Stakeholder M Model OP Occurrence
Probability SV Severity
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Risk Exposure as a Measure of Occurrence
Probability and Severity

• Risk Exposure
• 0 OP 1 SV L1, M2, H3
• Source Fall2000-Spring 2002 Projects

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Value of Identifying and Avoiding Model Clashes

• Source Fall 2002 projects (18 Projects)
• Teams identified model clashes and managed their
  risk

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Clash Types and their Contribution to Project Risk
Model-Clash Types Distribution
Contribution of Model-Clash Types to Risk
3
4
4
5
30
6
7
12
16
13
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Clash Types and their Contribution to Project
Risk
1.3
0.8
1.4
Success-
Success-
Success-
Product-
Process-
Property-
Product-
Process-
Product-
Success-
Property
Product
Success
Property
Property
Property
Product
Process
Process
Process
4
12
3
16
4
13
30
7
6
5
of Clashes
6
17
4
20
5
12
24
5
4
3
of Risk
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Inter and Intra Model Clashes and their
Contribution to Project Risk
Contribution of Inter and Intra Model Clashes to
Risk
Distribution of Inter and Intra Model Clashes
100
80
60
53
55
47
43
Total Model Clashes
40
20
0
Inter Model Clashes
Intra Model Clashes

• Inter model clashes caused majority of risk

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Questions?