11th Joint Conference, JCKBSE 2014（pp643-657） http://link.springer.com/chapter/10.1007%2F978-3-319-11854-3_56 の発表資料です。 　いくつかの選択肢があるとき（これがＯＲ分解）、ある選択肢が選ばれた妥当性をＧＳＮを使って主張したい場合、このようにすると良いのではという提案です。

1. A Study on the OR
decomposition of
goal-oriented analysis using GSN
2014/09/17
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2. Agenda
• 1.Introduction
• 2.Related work
• Representation of requirement- KAOS
• Elicitation of requirements-The Owner Partitioned Goal Model
• Notation of the evaluation process- GSN
• The difference between our study
• 3. Proposal method
• 4. Conclusion
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3. 1.Introduction
• Background：
• If any requirements are changed, the following process of the
requirement analysis have to be change.=>Changing cost is so much.
• So we do not want to change requirements.
• But it must be happened.
• Because we live in uncertain world.
• Business model change , Hardware change , Requirements have to be changed.
• Problem:
• Which requirements are changed?
• If We can know that , we can prepare to the changing requirements.
• Force:
• We can’t predict which requirements are changed
• Because we can’t predict the future.
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4. 1.Introduction
• Approach to solve the problem:
• In order to solve this problem, we discuss how to acquire the requirements.
• Elicitation : From top goal , elicit the requirements by refinement repeatedly.
• Choice: If there are conflicts between requirements , choice the requirements by evaluation.
• Evaluation and refinement are based on reasonable rationales.
• If these rationales are not reliable, these rationales may be changed.
• If these rationales are changed, Evaluation and refinement may be changed.
• If evaluations and refinements may be changed , related requirements will be changed repeatedly.
• So if we know which requirements will be changed , we know the reliability of
requirements’ rationales.
• In this study, we discuss the evaluation process for choice.
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5. 1.Introduction
• In this Study , We propose
• 1.A visualization method which will establish the reliability of the rationale for
the evaluation
• 2.A visualization method being the re-evaluation and updating of the
requirements after evaluation.
• Before we propose the methods, we explain
• the method of representation of requirements,
• the method of elicitation of requirements,
• the method of notation of the evaluation process
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6. 2.Related work-Representation of requirement-
KAOS
AND decomposition
OR decomposition
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All sub-goals are achieved
-> the goal is achieved
At least one sub-goals is achieved
-> the goal is achieved
*Choice => OR decomposition

7. 2.Related work- Elicitation of requirements-
The Owner Partitioned Goal Model
http://www.computer.org/csdl/
proceedings/apsec/2005/2465/
00/24650130.pdf
Process
1. Describe the
owner
2. Describe each
owners
requirements
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8. 2.Related work- Notation of the evaluation process-
GSN(Goal Structuring Notation)
http://www.goalstru
cturingnotation.info/
documents/GSN_Sta
ndard.pdf
Notation for the process
of argument by
“goal”
"strategy" (viewpoint)
"context”
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Use for
D-case
Assurance case

9. 2.The difference between our study
• KAOS
• Enables notation of requirements.=>Use it
• But it doesn’t enable to notate the reliability of the rationale for evaluation
• And it doesn’t mention to elicitation of requirements.
• The Owner Partitioned Goal Model
• Enables to elicit requirements.
• We extended this method. Not only owner, But also other stakeholders.
• GSN
• Enables to notate the evaluation process => Use It
• But GSN is for assurance , not for requirements analysis=> extends it.
• Extension 1 .We describe the goal not only supported goal by evidence but also not
supported goal by the rationale.
• Extension 2. We describe the rationale and the reliability of it to the GSN’s evaluation.
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10. 3. Proposal method
• In order to establish the reliability of the rationale for the evaluation,
we operate the following process.
• Describe the means.
• Describe the stakeholder.
• Describe each stakeholder’s requirements.
• Describe the goal tree of whole system with GSN.
• Evaluate and describe “the reliability of the rationale for the evaluation”.
• In order to show the re-evaluation point and updating of the
requirements, we operate the following process.
• When modifying, paint the modified part in gray.
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11. Ex: All the people can safely go over the road
• Describe the means => stakeholders=> stakeholder’s requirements
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Conflict
safety  Reasonable price
=> choice
Means
Stakeholders
Requirements

12. Describe the goal tree of whole system with
GSN
• we evaluate the means by stakeholder's requirements
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13. Describe the goal tree of whole system with
GSN
• we evaluate the means by stakeholder's requirements
Requirements
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Stakeholders
Means

14. Describe the goal tree of whole system with
GSN
• Evaluation
• 1. We filled the value
of the contribution
level in Table.
• 2. The evidence of the
reliability of the
rationale for the
evaluation.
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15. 3. Proposal method
• In order to establish the reliability of the rationale for the evaluation,
we operate the following process.
• Describe the means.
• Describe the stakeholder.
• Describe each stakeholder’s requirements.
• Describe the goal tree of whole system with GSN.
• Evaluate and describe “the reliability of the rationale for the evaluation”.
• In order to show the re-evaluation point and updating of the
requirements, we operate the following process.
• When modifying, paint the modified part in gray.
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Gray part=context => rationale change=>GSN have to be change
Gray part=strategy=>GSN changed => KAOS have to be change.

16. Ex. “Neighborhood” was added as a new
stakeholder.
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17. Ex. Modify on GSN
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18. Ex. Modify the stakeholder's requirement
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19. Modify the GSN
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20. 4. Conclusion
• The goal of this study : to show which requirements will be changed.
• We assume that
• More; the requirements are changed
• Less; the reliability of the rationale is low.
• We propose how to show the reliability of the rationale and re-evaluation
point.
• In particular we discuss the evaluation process of OR decomposition.
• As a result,
• We described the evaluation process with GSN ,the reliability of the rationale and
re-evaluation point can be described.
• Future work
• To make the tool of this method.
• To describe of the reliability of the rationale for another factor.( i.e. requirements)
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