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Advanced

Software

Engineering

Lecture

Introduction

to^ Software

Engineering

Prof.

Harold

Liu

Content ‡^ Basic

concept

of^ software

engineering

‡^ Computer

‐based

systems

engineering

‡^ Software

Process

‡^ Basic

elements

of^ software

project

management

2.^ What

is^ Software

Engineering?

‡^ Fall,

NATO

Technical

Committee

convened

nearly

first‐class

programmers,

computer

scientists

and^ industry

giants,

discuss

how^ to

cope^

with^ "software

crisis".

Fritz^ Bauer

at^ the

meeting

for^ the

first^ time

put^ forward

the^ "Software

Engineering"

concept. ‡^ The

establishment

and^ use

of^ sound engineering

principles

in

order^

to^ obtain

economically

software

that^ is

reliable

and

works

efficiently

on^ real

machines.”

‐‐‐^ Fritz

Bauer,

‡^ IEEE

Definition:

Software

engineering

is

(1)^ the

systematic,

standardized,

measurable

method

is^ applied

to^ software

development,

operation

and^ maintenance

of^ the

process,

the^ upcoming

engineering

applied

to^ software

development

process

thinking

(2)^ research

into^ (1) ‡^ Software

engineering

goals:

low‐cost,

high‐

quality,

on‐time

delivery

5.^ What

is^ Software

Process

？

‡^ Software

process

is^ the

development

of^ software

products

for^ a

group

of^ activities

and^ their

results.

‡^ All^

software

process

contains

four^ basic

activities:

Software

description,

software

development,

software

validation

and

software

evolution. ‡^ Different

software

processes

organized

in^ different

ways

in^ these

four^ activities,

which

may^ affect

the^ results

of^ the

progress

of

events. ‡ Different

bodies

may^ be

used^

to^ produce

the^ same

type^ of

process

products.

Benefits ‡^ A^ software

process

defines

that^ in

order

to^ achieve

the^ goals,

what

people

need^

in^ what

way^ at

what^

time^ what

kind^ of

work^

done^ (Goal,

Who,^ When,

How,^

What)

‡^ For

Customer,

User,^

Developer,

Manager,

a^ widely

applicable

software

process

allows

all^ stakeholders

to^ better

understand

their

role^ and

others’ role,

as^ what

to^ do^

at^ what

time.

‡^ Promote

the^ integration

process

to^ obtain

the^ "best

software

process.“ ‡ Make^

the^ company's

internal

training

standardized.

‡^ Due

to^ the

repeatability

of^ the

software

process,

useful

for^ the

development

schedule

arrangements

and^ cost

estimates.

‡^ From

a^ different

perspective

of^ the

software

process

described,

you^ get

a^ different

type^ of

process

models.

They

are: ‡ Workflow

model:

Describes

the^ sequence

of^ a^ series

of

activities,

inputs,

outputs

and^ inter

‐dependencie.

Here^

we

refer^ “Activities”as

human

activity.

‡^ Data

stream

or^ activity

model:

the^ software

process

described

as^ a^ set

of^ activities,

each^

of^ which

completes

certain

data

conversion.

The^ referred

level^

of^ activity

in^ this

model

is

below

the^ workflow

model.

‡^ Role/action

model:

Describes

the^ different

roles^

involved

in

the^ software

process

and^ its

responsible

activities.

Paradigm,

Methodology

‡^ Waterfall

Model

‡^ Waterfall

Model

with

Maintenance

Circle

‡^ Waterfall

Model

with

Prototyping

‡^ Spiral

Model

‡^ V^ Model ‡^ Phased

Development

Model

‡^ Incremental

and^

Iterative

Model

‡^ Rational

Unified

Process

8.^ Methodologies ‡^ Structured

Method,

by^ DeMarco,1978,

Yourdon

E.

and^ Constantine

L.^ et.

al.

‡^ Jackson

System

Development,

‡^ Object

‐Oriented

Method,

by^ Booch,

Rumbaugh et

al,^1991

Æ^ Design

Patterns

UML

(Unified

Modeling

Language)

-^ In^

OO^ principle

has^ been

throughout

the^ entire

software

life^ cycle,

it^ already

has^ an

impact

on^ 50+

OOA&D

methods.

-^ UML

is^ a^ kind

of^ modeling

language

for^ visualization,

decription,

structuring

and^

documentation,

mainly

for

the^ analysis

and^

design

phase

of^ system

modeling.

16

RUP ‡^ By

IBM^

Rational

‡^ Highlights^ „^

Use‐case

driven

（functionality

„^ architecture

‐centric

（design

„^ Iterative

and^ incremental

developments

（implementation

„^ Using

UML^

and^ other

tools

Tendency

for

Change

when

Using

OO

Paradigm

(Jacobson

et^ al.

1995)

High

Functionality

High

Interface

with^

the^ outside

world

Medium

Sequences

of^ behavior

Medium

Passive

object’s

attribute

Low

Long‐

lived^ information

structures

Low

Objects

derived

from

the^ application

Probability

for^ change

Characteristic

of^ SW

product/project

10.^

Problems

of^ Software

Engineering

‡^ Legacy

systems ‡^ Changing

requirements ‡^ Delivery ‡^ … ‡^ System

complexity

and^ details

(Mars

probe

failure)

‡^ Technological

uncertainty

(and^ in

turn^ the

understanding

of

developers) ‡ Communication

barriers

‡^ Requirement

uncertainty ‡^ Constant

changes

lead^ to

the^ software

degradation

‡^ Artificial

and^ the

market

risk

‡^ Costs,

reliability,

productivity,

reusability

problems

11.

Moral

responsibility

‡^ Professional

ethics is

very^ important

„^ Always

keep^ employer

and^ clients’ information

confidential

„^ Realistically

express

his/her

ability

to^ work,

do^ not

accept

work

beyond

the^ capability. „^ Should

be^ aware

of^ the

laws^ related

to^ patents,

copyrights,

etc.

„^ Avoid

computer

misuse.

‡^ ACM/IEEE/BCS

and^ other

organizations

issued

a^ Code

of

Professional

Conduct

and^ Ethics

(involving

only^ basic

moral

behavior)