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Requirements Modeling – Structured TIF-151551 REKAYASA DAN MANAJEMEN KEBUTUHAN

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  • Requirements

    Modeling – StructuredTIF-151551

    REKAYASA DAN MANAJEMEN KEBUTUHAN

  • Goals

    � Memahami konsep pemodelan terstruktur pada rekayasa

    kebutuhan.

    � Terampil dalam pembuatan diagram-diagram yang diperlukan

    dalam pemodelan terstruktur pada rekayasa kebutuhan.

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

    2

  • Konsep Dasar

    � Pertama kali dipopulerkan oleh T. DeMarco (1979) � Structured

    Analysis and System Specification

    � Perluasan notasi untuk kebutuhan real-time systems oleh Hatley danPirbhai (1987) – SA/RT � Strategies for Real-Time System Specification

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

    3

    Processes

    Data Behavior

  • Elemen-elemen Pemodelan

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

    4

    Data Dictionary

    Data Flow Diagram

    (DFD)

    ER Diagram

    State Transition Diagram

    (STD)

    Process Specification

    (PSPEC)

    Data Object Description

    Control Specification

    (CSPEC)

  • Data Dictionary

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

    5

    Representasi Simbol :

    = : composed of + : and

    { } : iterations of [….|…] : selection / or

    ( ) : optional “ “ : literal

    * * : comment/description

    Vend product (partly) :

    Name Element Type

    object [coin | slug](product) data

    product [ice cream | coffee | candy] data

    coins 0{[quarter | nickel | dime]}8 data

    product available [TRUE | FALSE] control

    [“YES” | “NO”]

    quarter *25 cents US currency*

    coin return request [TRUE | FALSE] control

  • Data Model – ER Diagram

    � Entitas (atribut dan nilai atribut)

    � Modalitas : tingkat mandatory (minimal)

    � Kardinalitas : tingkat relasi (maksimal)

    � Bentuk relasi

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

    6

    Manufacturer CarBuilds

  • Data Model – Data Object

    Description

    � Data object

    � represents a composite information

    � consists of a number of different attributes or properties

    � encapsulates data only � no operation applied to its data

    � can be external entity, thing, occurrence/event, role,

    organizational unit, structure, etc.

    � e.g. dimensions (height, weight, depth), cars (make, model, ID,

    body type, color, owner)

    � can be represented in a tabular representation

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

    7

  • Process Model – DFD

    � Useful for analyzing existing as well as proposed systems �process decomposition

    � Focus on the movement of data between external entities and processes, and between processes and data stores

    � A relatively simple technique to learn and use

    � Model elements: terminator, process, data flow, control flow, storage, control bar

    � The highest level (0) � Context diagram

    � Single process

    � Terminators

    � Data flows, control flows

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

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  • Process Model – Elemen2 DFD

    � Terminator

    � Representasi entitas eksternal

    � Notasi: persegi panjang

    � Tidak memproses data

    � Data flow

    � Representasi aliran data

    � Notasi: anak panah penuh

    � Umumnya satu arah

    � Hubungkan terminator, process dan storage

    � Control flow

    � Representasi aliran kontrol proses

    � Notasi: anak panah putus2

    � Hubungkan terminator, process dan control bar

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

    9

    Customer

    data

    control

  • Process Model – Elemen2 DFD

    (contn’d)

    � Process

    � Representasi aktifitas sistem

    � Notasi: lingkaran

    � Memproses data

    � Storage

    � Representasi tempat penyimpanan data

    � Notasi: dua garis paralel

    � Data flow in = diubah, data flow out = dibaca

    � Control bar

    � Representasi spesifikasi kontrol

    � Notasi: garis tegak

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

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    1

    Proses A

    data X

  • Process Model – Panduan DFD

    � Jumlah proses dalam satu diagram DFD : 4 + 2

    � Maks. 4 level dekomposisi (DFD/CFD)

    � Dekomposisi fungsional (DFD) :

    � fungsi-fungsi yang saling berhubungan dikelompokkan

    � fungsi-fungsi yang tidak berhubungan dipisahkan

    � setiap fungsi dispesifikasi hanya sekali

    � Data flow membawa informasi yg diperlukan oleh sebuah proses untuk transformasi, control flow membawa informasi yang harusdiinterpretasikan untuk merubah perilaku sistem dan/ aktifasi proses

    � Proses pemodelan DFD/CFD adalah proses iterasi, tidak sekali jadi

    � Penjenjangan CFD harus sesuai dengan DFD

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

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  • Data – Control Identification

    � Identify data first rather than control � to know what you are

    controlling first

    � Continuous signals, and processes that act on them, are

    always categorized as data

    � Discrete signals, and processes that act on them, are usually

    categorized as control

    � Terms like activate, turn on, engage and execute are usually

    associated with control requirements

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

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  • Process Model – DFD/CFD

    Leveling

    � Must be consistent

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

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  • Examples

    � Vending Machine System

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

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  • Data/Control Context Diagram

    (DCD/CCD)

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

    15

    Vendproduct

    Customer

    returned coins

    0*

    Customer

    product

    object

    customer

    selection

    slug

    coin return

    request product

    available

  • Data/Control Flow Diagram

    (DFD/CFD Level 1)

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

    16

    1*

    Get

    customer

    payment

    2p

    Get

    product

    price

    3p

    Validate

    payment

    4p

    Get valid

    selection

    5*

    Dispense

    change

    6p

    Dispense

    product

    price table

    coins

    products

    returned

    coins

    product

    object

    customer

    selection

    slug

    coin return

    request

    payment

    price

    valid

    selection

    change due

    valid

    selection

    coin detectedsufficient

    payment

    product

    dispensed

    product

    available

    product

    available

  • Data/Control Flow Diagram

    (DFD/CFD Level 2)

    � DFD/CFD level 2 : Dispense change

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

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    5.1p

    Get

    change

    coin

    coin return

    request

    5.2p

    Get

    payment

    coin

    product

    availablechange due

    coins

    payment

    payment

    coins

    change coinsreturned

    coins

  • Process Model – Process

    Specification (PSPEC)� PSPEC – Validate payment (Process 3)

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

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    Inputs : payment (data in)

    price (data in)

    Outputs : change due (data out)

    sufficient payment (control out)

    Body :

    IF payment >= price THEN

    change due = payment – price

    sufficient payment = TRUE

    ELSE

    change due = 0

    sufficient payment = FALSE

    END IF

  • Behavior Model

    � CSPEC – Dispense change : Process Activation Table (PAT)

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

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    coin return request

    product available

    get change coin

    get payment

    coin

    TRUE TRUE 1 0

    D/C FALSE 0 1

  • Behavior Model (contn’d)

    � State Transition Diagram (STD)

    Rekayasa dan Manajemen Kebutuhan | Requirements Modeling - Structured

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    Waiting for a coin

    Waiting for selection

    Dispensing product

    Returning payment

    initial

    accept new coin

    payment returned

    accept new coincoin detected

    accept customer

    requestproduct dispensed

    accept new coin

    sufficient payment

    dispense product

    product

    available=FALSE

    return payment

    coin return request

    return payment