1. Week 3 – Modelling the Process and Life Cycle
Software Engineering
Week 3 – Modelling the Process and Life Cycle
A.A. Gde Bagus Ariana, S.T.

2. Content define s/w process, product and life-cycle
describe various s/w dev. Models
Waterfall Model
“V” Model
Prototyping Model
Throw away
Evolutionary
RAD Model
Incremental Model
Iterative Model
Spiral Model
Hari ini kita akan membahasan beberapa hal-hal penting yang berkaitan dengan Pemodelan Proses dan Siklus Perekayasa PL.
Menjelaskan ttg proses, produk dan siklus
Menjelaskan beberapa model pembangunan PL
Model Air Terjun
Model “V”
Model Prototipe
Model RAD
Model Spiral

3. ACTIVITIES (TASKS), CONSTRAINTS, RESOURCES
Understand Process
Definition
Process
OUTPUT
[ Results ]
[ Product ]
[ Set of Goals ]
[ Standards ]
INPUT
[ Source ]
[ Requirements ]
ACTIVITIES (TASKS), CONSTRAINTS, RESOURCES
PROCEDURES
TOOLS & TECHNIQUES
Process
Characteristics
Prescribes all major process activities
Uses resources
Composed of sub processes
Has entry & exit criteria
Organised in sequence
Has guiding principles
Has constraints or controls
Jelaskan definisi proses?
FINAL OUTPUT
[ Results ]
[ Product ]
[ Set of Goals ]
[ Standards ]

4. Requirement Analysis and Definition
Understand Process
Example
Requirement Analysis and Definition
ACTIVITIES (TASKS), CONSTRAINTS, RESOURCES
INPUT
[statements from user ]
OUTPUT
[set of requirements]
PROCEDURES
TOOLS & TECHNIQUES
Constraint
budget
schedule
task/tugas
Constraints/ hambatan-hambatan
Resources/ sumber daya
Activities
Interviews
Observation

5. Waterfall Model

6. Operation & Maintenance
Waterfall Model
Evaluates costs & benefits of proposed application.
Produce feasibility report
Problem definition
Alternative solutions & benefits
Required resources & scheduling
Detailed Analysis
Detailed Design
Construction
Testing
Operation & Maintenance
Feasibility Study
System Delivery
Status Quo & Problem Identification
Linear sequential model , classic life cycle, system development life cycle (SDLC)

7. Operation & Maintenance
Waterfall Model
Evaluates costs & benefits of proposed application.
Produce feasibility report
Problem definition
Alternative solutions & benefits
Required resources & scheduling
Detailed Analysis
Detailed Design
Construction
Testing
Operation & Maintenance
Feasibility Study
System Delivery
Status Quo & Problem Identification
Linear sequential model , classic life cycle, system development life cycle (SDLC)

8. Operation & Maintenance
Waterfall Model
Identifies all aspects of requirements
Functionality
Quality
Produce req specification document
Functional req
Non-functional req
Quality controls
Detailed Analysis
Detailed Design
Construction
Testing
Operation & Maintenance
Feasibility Study
System Delivery
Status Quo & Problem Identification
Requirement Analysis
Investigation
Linear sequential model , classic life cycle, system development life cycle (SDLC)

9. Operation & Maintenance
Waterfall Model
Detailed Analysis
Detailed Design
Construction
Testing
Operation & Maintenance
Feasibility Study
System Delivery
Status Quo & Problem Identification
Decomposing system into modules
Produce design spec. and document
S/W Architecture
Its relationships
Program Design
System Design
Linear sequential model , classic life cycle, system development life cycle (SDLC)

10. Operation & Maintenance
Waterfall Model
Evaluates costs & benefits of proposed application.
Produce feasibility report
Problem definition
Alternative solutions & benefits
Required resources & scheduling
Detailed Analysis
Detailed Design
Construction
Testing
Operation & Maintenance
Feasibility Study
System Delivery
Status Quo & Problem Identification
Linear sequential model , classic life cycle, system development life cycle (SDLC)
Coding
Module Testing
Unit & Integration Test
System Test
Function Test
Performance Test
User Acceptance Test
Installation Test

11. Operation & Maintenance
Waterfall Model
Evaluates costs & benefits of proposed application.
Produce feasibility report
Problem definition
Alternative solutions & benefits
Required resources & scheduling
Identifies all aspects of requirements
Functionality
Quality
Produce req specification document
Functional req
Non-functional req
Quality controls
Detailed Analysis
Detailed Design
Construction
Testing
Operation & Maintenance
Feasibility Study
System Delivery
Status Quo & Problem Identification
Requirement Analysis
Investigation
Program Design
System Design
Decomposing system into modules
Produce design spec. and document
S/W Architecture
Its relationships
Linear sequential model , classic life cycle, system development life cycle (SDLC)
Coding
Module Testing
Unit & Integration Test
System Test
Function Test
Performance Test
User Acceptance Test
Installation Test
System / Information engineering
[Roger. S. Pressman]

12. Waterfall : Advantages
Detailed layout
Suitable for user  not familiar with s/w development
Explicitly state prior deliverables
Focuses on documentation & artefacts
Rinci dan detail
Cocok untuk pengguna/user yang belum terbiasa dengan perancangan perangkat lunak
Sangat fokus pada dokumentasi tiap-tiap proses

13. Waterfall : Disadvantages
Rare adherence to sequence
Iterations  confusion
Natural uncertainty vs. model req. stage
Does the system meet user expectations?
Unclear paths
nothing about back and forth activities
End-product realisation  end
No guidelines for mgmt./developers if changes occurs during the cycle
Jarang sekali mematuhi urutan
Proses iterasi menimbulkan kebingungan
Ketidakpastian vs Proses Requirement
Apakah sistem telah memenuhi harapan pengguna?
Produk telah releasisasi = selesai
Tidak ada pedoman untuk manajemen, jika perubahan terjadi selama siklus

14. “V” Model Requirements Analysis System Design Program Design Coding
Acceptance test to VALIDATE Customers Requirements
Requirements Analysis
System Design
Program Design
Coding
Operation & Maintenance
Acceptance Testing
System Testing
Unit & Integration Testing
V model merupakan variasi dari model waterfall dengan lebih terfokus pada pengecekan (verifikasi dan validasi)
Unit & Integration test to VERIFY Program Design
System test to VERIFY System Design

15. “V” Model
Problems found during verification and validation then re-execute to fix and improve the requirements, design and code before the testing steps on the right are re-anacted.
Waterfall model focus is on documents and artifacts but in V model focus is on activity and correctness.
Masalah/problem yang ditemukan saat proses verifikasi dan validasi langsung diperbaiki dengan melakukan proses requirement, design dan coding sebelum proses testing diberlakukan kembali
Waterfall model fokus pada dokumentasi kejadian sedangkan “V” Model fokus pada aktifitas dan perbaikan

16. Prototyping
Model

17. Prototyping Model Partially developed product
Customers & developers examination
Examine some aspect of proposed system
Suitability or Appropriateness
Quick construction  all or part
Understand or clarify issues
Partially developed product
Enables customers & developers to examine
Aspect of the proposed system
Decide if it is suitable or appropriate for the finished product
Allows all or part of a system to be constructed quickly
To understand or clarify issues

18. Prototype Requirements
Prototyping Model
One / more of the loops may be eliminated
? goals of the prototyping (reduce risk and uncertainty in development)
May begin with nominal set of requirements
Lists of Revisions
Prototype System
Prototype Design
Test
Lists of Revisions
Delivered System
Prototype Requirements
Alternatives are explored
Having interested parties look at possible screen, reports etc.
Based on what they want, the requirements are revised
System Requirements [sometimes informal or incomplete]

19. Prototype Requirements
Prototyping Model
Alternative design explored
Decided design revised until satisfied
Alternative design reveals problem in req activities
Drop back to req activity
Lists of Revisions
Prototype System
Prototype Design
Test
Lists of Revisions
Delivered System
Prototype Requirements
Eventually, system is coded
Alterations discussed
# of iterations
System Requirements [sometimes informal or incomplete]

20. Evolutionary Prototyping
An approach to system development where an initial prototype is produced and refined through a number of stages to the final system.
deliver a working system to end-users
used for systems where the specification cannot be developed in advance e.g. AI systems and user interface systems
Verification is impossible as there is no specification. Validation means demonstrating the adequacy of the system
uses CASE , 4GL tools, GUI toolkits
rapid development (using incremental model)

21. Throw-away Prototyping
A prototype which is usually a practical implementation of the system is produced to help discover requirements problems and then discarded.
To validate or derive the system requirements
Not an actual system to be delivered to the user
Throw-away = dibuang

22. Rapid App. Dev (RAD)

23. Rapid App. Dev. (RAD) Incremental - Short development cycle
End users make evaluation on the increment and make proposals for later increments
Short development cycle
High speed adaptation
Linear models (eg. Waterfall)
Rapid development
Uses component-based construction
Short period
60 – 90 days

24. Application generation
Rapid App. Dev. (RAD)
Business modeling
Data modeling
Process modeling
Application generation
Testing & turnover
Team # 1
Team # 2
Team # 3
Modelling business function information flow
What info ?  business process
What info is generated ?
Who processes it ?
Who generates it ?
Where does info go to next ?
Info flow refined into data objects to support business process
Data object characteristics identified
Relationship between each data object defined
60 – 90 days

25. Application generation
Rapid App. Dev. (RAD)
Data objects transformed to implement a business function
Processing description created
Add, Modify, Delete & Retrieve data objects
Business modeling
Data modeling
Process modeling
Application generation
Testing & turnover
Team # 1
Team # 2
Team # 3
Applies 4th Generation techniques (E.g. Code generators)
Reusable components
Automated tools
Since emphasizes on reuse
Many components have already been tested
New components to be tested only
60 – 90 days

26. Incremental Model
Requirements is partitioned into subsystems by functionality
Use Case 1
Use Case 2
Use Case 1
Use Case 2
Use Case 3
Use Case 1

27. Iterative Model
Delivers a full system at the beginning and then changes the functionality of each subsystem with each new release
Use Case 1
Use Case 2
Use Case 3
(release 1)
Use Case 1
Use Case 2
Use Case 3
(release 2)
Use Case 1
Use Case 2
Use Case 3
(release 3)

28. RAD: Advantages Suitable for short projects
Minimum testing difficulties
Reusable components
Quick development
Automated tools
Straight forward approach

29. RAD: Disadvantages Not suitable for large projects
Multiple teams working on different sites
Team utmost commitment  deadlines
Not suitable for
Systems  requires fine tuning
System  new tech. interaction
System  other sys. interaction

30. Spiral Model

31. Spiral Model Simplified form
Waterfall model plus risk analysis preceding each phase
If all risks cannot be resolved, the project is immediately terminated

32. Spiral Model
View of spiral

33. Spiral Model PLAN DEVELOP AND TEST DETERMINE GOALS, ALTERNATIVES,
CONSTRAINTS
EVALUATE ALTERNATIVES
AND RISKS
start
Requirements,
life-cycle plan
Budget1
Alternatives1
Constraints1
Risk analysis1
Risk analysis2
Risk analysis3
Risk analysis4
Constraints2
Constraints3
Constraints4
Budget2
Budget3
Budget4
Alternatives2
Alternatives3
Alternatives4
Prototype1
Proto-
type2
type3
type4
Concept of
operation
Software
requirements
Validated
Development
plan
Integration
and test plan
design
Validated,
verified design
Detailed
Code
Unit test
System
test
Acceptance
Implementation

34. Spiral Model
Process is represented as a spiral rather than as a sequence of activities with backtracking.
Each loop in the spiral represents a phase in the process.
No fixed phases such as specification or design - loops in the spiral are chosen depending on what is required.
Risks are explicitly assessed and resolved throughout the process.

35. Spiral Model Objective setting Risk assessment and reduction
Specific objectives for the phase are identified.
Risk assessment and reduction
Risks are assessed and activities put in place to reduce the key risks.
Development and validation
A development model for the system is chosen which can be any of the generic models.
Planning
The project is reviewed and the next phase of the spiral is planned.

36. Summary define s/w process, product and life-cycle
describe various s/w dev. Models
Waterfall Model
“V” Model
Prototyping Model
Throw away
Evolutionary
RAD Model
Incremental Model
Iterative Model
Spiral Model

37. Question?