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    RequirementsEngineering:

    Introduction

    Part One

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    Systems Engineering

    concepts

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    Systems Engineering

    All the activities involved in: procuring, specifying, designing,

    implementing, validating, deploying,operating, and maintaining socio-

    technical systems. Services

    Constraints

    Uses Involvement of a range of

    professional disciplines

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    Systems Engineering

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    Systems Engineering

    Systems Requirements Engineering

    Software Requirements Engineering

    Non-Software RequirementsEngineering

    In another context: Software Engineering

    Software Requirements Engineering

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    RequirementsEngineering

    concepts

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    By the early 1990s, RE had emergedas a field of study in its own right, aswitnessed by the emergence of twoseries of international meetings

    0913409930 Ato Ali 66849303250 taye

    the IEEE sponsored conference andsymposium,

    the establishment of an international

    Requirements Engineering /RE/

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    Three radical new ideas

    1.modeling and analysis cannot beperformed adequately in isolationfrom the organizational and social

    context in which any new system willhave to operate.

    1.RE should not focus on specifyingthe functionality of a new system,but instead should concentrate on

    modeling indicative and optative

    RE

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    3. the attempt to build consistent andcomplete requirements models isfutile. RE has to take seriously the

    need to analyse and resolveconflicting requirements, to supportstakeholder negotiation, and to

    reason with models that containinconsistencies.

    RE

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    Why-What-Whodimensions

    Peopl

    e

    Problems,opportunities,Domainknowledge

    Software-to-

    be

    Device

    s

    Existing

    software

    Services,Constraints,Assumptions

    Why?

    What?

    Who?

    Objectives

    System-as-is System-to-be

    Satisfies

    Assignedto

    Environment

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    Why-what-who dimension

    Why

    Contextual reasons

    Limitations of the system-as-is

    Opportunities to be exploited

    What

    Functional services

    System assumptions

    Constraints

    Who

    Assignment of services

    RE

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    obstacles to good RE practices

    cigarette smokers who know thatsmoking is pretty unhealthy but keepsmoking

    Spending effort & money

    before the project contract is signed,without guarantee

    Pressure on tight schedule, short-termcosts, catching up latest technology

    Too little RE economics research

    RE technology felt too heavyweight or too

    RE

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    Why RE?

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    What RE?

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    thank you

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