Software Engineering CD Ac

7/30/2019 Software Engineering CD Ac

1/45

SoftwareEngineering B

SGandhi


2/45

What is Engineering and why

do we need it? Better Quality

Better Price

Better Turnaround times


3/45

Better Turnaround times

Software Engineering consists of

Engineering Practices

Management Practices

Support Practices

Engineering Practices are covered more in detail later

Management Practices are about

Estimations

Planning

Monitoring and Control

BSGandhi


4/45

Quality Basics

What is Quality

Meeting the specifications

Meeting the requirements

Fitness for use

Meeting the stated, implied and legal requirements

Minimum loss to the society


5/45

How do we achieve Quality?

Inspections & Testing - Quality Control

Reviews, verifications, making sure that you are doing right

Quality Assurance

Process Approach

TQM

Six Sigma

Quality by Design


6/45

Software Challenges

Software is developed, not manufactured

Software does not wear out

Software is mostly custom built

Software does not contain sub-assemblies from outsiders

BSGandh

i


7/45

Challenges (contd)

Y2K problem !!!

Some small programs and tools live longer than expected

No visibility to decide how much is completed (during

development)

No proper estimation of effort and schedule

BSGandh

i


8/45

Myths

Management

We have a book containing all standards

If we are behind schedule, we can add more programmers and

catch up

We can always decide to outsource if we do not know how tobuild

BSGandh

i


9/45

Myths (contd)

Customer

Basic requirements should be good enough to start coding. We

can add more details of what we want later

We agree that requirements continually change, but so what?

Change can easily be accommodated since software is flexible

BSGandh

i


10/45

Myths (contd)

Programmer

Once we get the program to work, our job is done

Until I finish coding, how do I assess the quality?

The only deliverable work product is a working program

Software engineering practices make us write more documents

and slows down our workBSGandh

i


11/45

Source: Standish Group Report (2001)

11

Project Failure Rates Software Projects

Challenged

Succeeded

Failed 28%

46%

26%


12/45

Process approach

What is a process

A good process can deliver good output

Engineering, Management and Support processes

Software Development Life Cycle

Phases of SDLC

BSGandh

i


13/45

Software Development

Software life cycle processes that comprise the activities of

Requirements analysis

Design

Coding

Testing

Installation & Acceptance

User Support

SoftwareProjectManagemen

t

13


14/45

Requirements Analysis

Requirements specification of the characteristics to be possessed by

the software project or service

Requirements analysis elicitation, documentation, review and

approval of requirements


t

14


15/45

Design

Design logical view of the implementation of the solution meeting

customer requirements

Data design data structures, data base elements

Architectural design sub-systems, modules and programs

Interface design user and external environment


t

15


16/45

Coding

Coding converting the logic specified in the design in to programs as

per chosen programming language


t

16


17/45

Testing

Testing to ensure that the product is working according to the

requirements

Levels of testing unit, module, integration, system and acceptance


t

17


18/45

Installation and Acceptance

Developed software to be installed on the user environment

User training

User acceptance

Softw

areProjectManagemen

t

18


19/45

User Support

Problem resolution

Functionality enhancements

Migration to new environments

Softw

areProjectManagemen

t

19


20/45

Process Architecture

For all the software development activities the process architecture

defines

Entry and exit criteria

Inputs and outputs

Participants and responsibilities

Activities to be carried out

Verification and approval

Standards

Softw

areProjectManagemen

t

20


21/45

Software Development Life

Cycle Model A framework containing the processes, activities and the tasks

involved in the development, operation and maintenance of a

software product spanning the life of the system from the definition of

its requirements to the termination of its use (ISO/IEC 12207)

Softw

areProjectManagemen

t

21


22/45

SDLC Models

Waterfall model

Spiral model

Prototype model

Iterative model

Rapid application development model

Softw

areProjectManagemen

t

22


23/45

Waterfall Model

Also known as classic life cycle model, linear sequential model

This model suggests a systematic and sequential approach to software

development that begins at requirements analysis and progresses

through all life cycle phases sequentially

Softw

areProjectManagemen

t

23


24/45

Waterfall Model (Contd)

Softw

areProjectManagemen

t

24

RA

D

C

T

I & A

CS


25/45

Waterfall Model

Softw

areProjectManagemen

t

25

System Testing

Integration Testing

Coding and Unit Testing

Detailed Design

High Level Design

Software Requirement Specifications

Users Software Requirements

Acceptance Testing

Warranty


26/45

Softw

areProjectManagemen

t

26Project Management

Software

Development

Quality

Assurance

Coding

Contract WarrantyReview

/ Test

Users Software

Requirements

AcceptanceTesting

Software

RequirementsSpecifications

SystemTesting

High LevelDesign

IntegrationTesting

DetailedDesign

UnitTesting

V MODELV MODEL


27/45


Development activities carried out sequentially

Review and approval of each phase outputs

Model does not permit going back and forth

If any defect found, go back to the originating phase and start

traversing sequentially all over again

Softw

areProjectManagemen

t

27


28/45


Suitable for projects where

Requirements are clearly defined

Small and medium term duration

Stable technology

Familiarity with the domain and development environments

Softw

areProjectManagemen

t

28


29/45


Advantages:

Projects under control

Pre-defined outputs at every phase

Tracking changes is easy

Early identification of slippages, if any

Softw

areProjectManagemen

t

29


30/45


Disadvantages:

In real life, customer requirements do change

Customer appraisal of completed work - not feasible always

Phases can not run concurrently

Softw

areProjectManagemen

t

30


31/45

Spiral Model

In a spiral model, software is developed in a series of incrementalreleases

The spiral model is divided in to a number of framework activities or

task regions

Softw

areProjectManagemen

t

31


32/45

Spiral Model (Contd)

Softw

areProjectManagemen

t

32

R A

D

C

T

I&A

S


33/45


Suitable for large projects with multi-location implementation

Each Spiral consists of a deliverable product

Feedback of each spiral is incorporated in the next spiral

Customer can start using the system after every spiral

Each Spiral consists of a waterfall model

Softw

areProjectManagemen

t

33


34/45


Advantages:

Useful for large projects

Customer requirements evolve over a period Early availability of usable system

Disadvantages:

Total blue print should be available in the beginning

Basic concepts in the underlying layer can NOT be changedSoftw

areProjectManagemen

t

34


35/45

Prototype Model

A prototype model is a representation of a real life situation, which canbe evaluated by the user

A prototype is developed based on the initial understanding of the

customer requirements

A visible working prototype helps customer to define the requirements

Softw

areProjectManagemen

t

35


36/45

Prototype model (contd)

Softw

areProjectManagement

36

Intial

Requirements

Design

Code

Test

Design Code Test


37/45

Prototype Model (Contd)

Prototype model is used for eliciting customer requirements as well asidentifying user machine interaction

Prototype model is used in product development or for developing a

new application for a customer

Softw


37


38/45

Prototype Model (Contd)

Advantages : Can be used when customer is not sure about what he

wants

Faster way of finalising the requirements Useful for new technologies and domains

Disadvantage : A prototype if used in a production environment, may lack

quality or maintainabilitySoftw


38


39/45

Incremental Models

BSGandhi


40/45

BSGandhi


41/45

Agile Principles

Highest Priority Customer Satisfaction

Welcome changing requirements Even late in the

development

Deliver working software frequently

Business people and developers work together

Build Projects around motivated individuals

Most efficient method of conveying information within

development teams face to face

Softw


41


42/45

Agile Principles (contd)

Working software is the primary measure of progress

Simplicity is essential

Best performance of any individual will emerge from self-

organizing teams

Softw


42


43/45

Phases in Agile Models

BSGandhi


44/45

Agile SDLC Models

SCRUM

Sprints

Daily Stand-up meetings (Progress, Problems and Plan)

SCRUM Master

Backlog Sprints

Softw


44


45/45

Agile SDLC Models

Extreme Programming

OO is the preferred development paradigm

Only four phases Planning, Design, Code and Test

User Stories that describe the functionality

Design to follow keep it simple approach Coding - continuous refactoring and pair programming

Softw


45

Date post:	14-Apr-2018
Category:	Documents
Upload:	shivaprasad-bolla
View:	216 times
Download:	0 times

Software Engineering CD Ac

Documents