GRL Introduction

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GRL Introduction

Lin LiuUniversity of TorontoApril 2001

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Why Goal-Orientation??van Lamsweerde (ICSE 2000)

•Systematic derivation of requirements from goals

•Goals provide rationales for requirements

•Goal refinement structure provides a comprehensible structure for the requirements document

•Alternative goal refinements and agent assignments allow alternative system proposals to be explored

•Goal formalization allows refinements to be proved correct and complete.

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Where Are We??

Late Late

requirements

requirements

Architectural

Architectural

design

design Detaile

d

Detailed

design

design

Implementatio

n

Implementatio

n

GRLGRL

KAOSKAOS

SDLSDL

UMLUML

object-oriented object-oriented programmingprogramming

[Mylopoulos AOIS’99]

UCMUCM

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Development-World model refers to and reasons about…

Operational-World models

Alt-1 Alt-2 To-beAs-is

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Outline

1. Goal-oriented modeling concepts in GRL

2. An example goal-oriented non-functional requirement analysis process

3. Combined use of goal and scenario from requirement to architectural design

4. Agent-oriented concepts in GRL

5. Related works

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Goals and Softgoals in GRL

GOAL CallServicesBeSupported

“Both Narrowband and Wideband voice, data and image services besupported.”

ATTRIBUTE

Object: TDMA

HOLDER IncomingCallServiceProvider

SOFTGOAL MinimizeCost OF TDMA

ATTRIBUTE

Budget : “less than 500k$”

HOLDER IncomingCallServiceProvider

SOFTGOAL MaximizeCallCapacity OF TDMA

ATTRIBUTE

Rates : “At least two times current capacity”

HOLDER IncomingCallServiceProvider

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Tasks in GRL

TASK MakeVoiceConnectionOverLAN

ATTRIBUTE

Object: IncomingCall

HOLDER IncomingCallServiceProvider

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Goal Refinement: Means-ends Link

Task Refinement: Decomposition Link

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Softgoal Operationalizations: Contribution Relationship

Side-effects to softgoals: Correlation Relationship

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Resource in GRLRESOURCE LANBandwidth

ATTRIBUTE

Object: VoiceCall

HOLDER IncomingCallServiceProvider

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Non-Intentional Elements in GRL

•Acting as parameters in GRL intentional elements, i.e., topics of softgoal, “Object” attributes of goal, task and belief

•Referring to entities of an external model, such as responsibilities in UCM, class/objects in UML class diagram,…ELEMENT IncomingCallService

IS scenario ICSFROM URN-FR

MODEL ICS_service_01

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Belief in GRL

Convergence of media reduces cost of ownership

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Outline

1. Goal-oriented modeling concepts in GRL

2. An example goal-oriented requirement analysis process

3. Combined use of goal and scenario from requirement to architecture design

4. Agent-oriented concepts in GRL

5. Related works

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Softgoal Operationalization Example

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Softgoal Operationalization Example (cont’d)

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Example (cont’d)

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Example (cont’d)

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Outline

1. Goal-oriented modeling concepts in GRL

2. An example goal-oriented requirement analysis process

3. Combined use of goal and scenario from requirement to architecture design

4. Agent-oriented concepts in GRL

5. Related works

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Goal model in GRL

GOAL CallServicesBeSupported

“Both Narrowband and Wideband voice, data and image services besupported.”

ATTRIBUTE

Object: TDMA

HOLDER IncomingCallServiceProvider

SOFTGOAL MinimizeCost OF TDMA

ATTRIBUTE

Budget : “less than 500k$”

HOLDER IncomingCallServiceProvider

SOFTGOAL MaximizeCallCapacity OF TDMA

ATTRIBUTE

Rates : “At least two times current capacity”

HOLDER IncomingCallServiceProvider

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An Original unbounded UCM scenario corresponding to Goal “Call Services Be Supported”

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Bounded UCM scenarios of Solutions: Reside VoiceCoder in (1) Base Station; or (2) in Switch

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Design Alternatives & Their Contributions to NFRs

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Outline

1. Goal-oriented modeling concepts in GRL

2. An example goal-oriented requirement analysis process

3. Combined use of goal and scenario from requirement to architecture design

4. Agent-oriented concepts in GRL

5. Related works

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Agent-Orientation in GRL•Actors are semi-autonomous, partially

knowable•Strategic actors, intentional dependencies•Can be considered as goal-holders

Meeting Scheduling Meeting Scheduling ExampleExample

“Strategic Dependency” Model

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Revealing goals, finding alternatives

•Asking “Why”, “How”, “How else”

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Scheduling meeting …with meeting scheduler

ConsiderConsider

1.1. Technology as enablerTechnology as enabler

2.2. Networked systems and organizationsNetworked systems and organizations

3.3. Increased inter-dependency and Increased inter-dependency and vulnerabilityvulnerability

4.4. Limited knowledge and controlLimited knowledge and control

5.5. Openness and uncertaintiesOpenness and uncertainties

6.6. CooperationCooperation

7.7. Boundaries, locality, identityBoundaries, locality, identity

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Distributed Goal Model with Meeting Scheduler

•SR2

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Outline

1. Goal-oriented modeling concepts in GRL

2. An example goal-oriented requirement analysis process

3. Combined use of goal and scenario from requirement to architecture design

4. Agent-oriented concepts in GRL

5. Related works

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Goal-Oriented Requirements Engineering

(GORE) •GORE is gathering momentum

CSD – Feather 87… KAOS – van Lamsweerde, … Inquiry Cycle – Potts, Anton EKD – Bubenko, Rolland, Loucopoulos Win-Win – Boehm NFR – Chung, Mylopoulos, …

Hopefully, MOMENTUM >>>•Z.URN proposal to ITU-T (Nov. 2000)

GRL

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Goal + scenario in RE and in Architectural Design

•Krutchen’s 4+1 model of software architecture

•Software Architecture Analysis Method (SAAM)

•Van Lamsweerde and Willement

•CREWS-L’Ecritoire approach of Collete Rolland et al.

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Resources regarding GRL

Home of GRL http://www.cs.toronto.edu/km/GRL/

Tool web site http://www.cs.toronto.edu/km/OME/

References:• Chung, L., Nixon, B.A., Yu, E.and Mylopoulos, J. Non-

Functional Requirements in Software Engineering. Kluwer Academic Publishers, 2000.

• Yu, E. and Mylopoulos, J. Why Goal-Oriented Requirements Engineering. In Proceedings of the 4th International Workshop on Requirements Engineering: Foundations of Software Quality. June 1998, Pisa, Italy. E. Dubois, A.L. Opdahl, K. Pohl, eds. Presses Universitaires de Namur, 1998. pp. 15-22.

Also at: http://www.cs.toronto.edu/~eric