Ict 213 lecture 1

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System Analysis and Design

Prof. Dr. ir. S. S. Msanjila

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Course Materials

Book: Requirements analysis and system design, 3rd edition (Leszek A. Maciaszek)

Website: http://www.comp.mq.edu.au/books/rasd3ed/ReadersArea/lectureslides.htm

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Course outline - Lectures

Introduction to conceptual modeling and visual modeling (Sect. 1.1 & 1.4, &

Chapter 3)

Identification of users, and business requirements (Chapter 2)

Specification of system requirements (Chapter 4)

System Modeling (Chapter 5)

Designing system architecture (Chapter 6)

Designing user interfaces (Chapter 7)

System analysis

System design

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Lecture 1

Introduction to System Analysis and Design

&

Visual modeling with UML

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Introduction

Model: • An abstraction of reality, an abstract

representation of reality

• Applied to guide the implementation of

targeted product

System modeling: • Representing concepts using some defined

constructs

• Conceptual models (conceptual constructs)

represent some optional solutions that can be

implemented

For software developments it is referred to as “system

analysis and design”

In computer science • Addresses the capturing of activities and

processes that need to be modeled to guide the

implementation of a system

Physical

process

Model of

a process

System

automating

the process

Analysis

Designing

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System and software development process

Why having a process: Developing a system/software is

also an engineering project:

• Has goals, deadlines, budget

• Involves a number of stakeholders

• Needs some managerial skills

A system/software development is a complex engineering project

• Needs a properly defined process

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Complexities in developing system/software

Of the development process: • Size of the system/software

• Involved developers/experts

• Interdependencies between

components/modules

• Number of stakeholders

Of the system/software:

• Number of applications

• Application domains • Computational-intensive vs. Data intensive

• Conformity • Hardware & Software

• Changeability • Fluctuation/variation of business

requirements

• Visibility • Privacy vs. sharing code

• Security vs. access of code

As an engineering product,

systems can be duplicated: • Duplication cost is too low

as compared to that of

development

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The accidents of software development

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Software life cycle

Software life cycle represents an ordered set of activities conducted

and managed to support the creation and operation of software

• Activities are mostly performed sequentially

• Methods are applied to guide performing the processes

A software life cycle consists of:

• Exact phases (during which transformation occurs)

• Methods (methodologies)

• Applied modeling approach

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Software life cycle - Phases

3. Implementation

4. Operation

2.

Design 5.

Maintenance

1.

Analysis

1.

Analysis

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1. System (business) analysis

Requirement Analysis: Identifying, specifying and modeling

customers’ (users’) requirements:

• Identification (Business analyst)

• Specification (System analyst)

• Documentation (System analyst and system designer)

Types of requirements: • Functional requirements

• Non-functional requirements

Focuses on:

• Identification of users,

• Characterization of user requirements

• Specification of functionalities

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3. Implementation

4. Operation

2.

Design 5.

Maintenance

1.

Analysis

2.

Design

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2. System Design

Addresses:

• Structure of the system

• Internal components of the system

• Components supporting external interactions

• System architectures

Designing process must take into account

the software and hardware platforms that

system will installed

Focuses on:

• Designing models and architectures of the intended system

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3. Implementation

4. Operation

2.

Design 5.

Maintenance

1.

Analysis

3. Implementation

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3. System Implementation

Focus:

• Development of the system by implementing the needed codes.

• Testing developed components

• Loading data into databases

• Setting required hardware

• Validation and verification of:

• Functionalities

• External interactions

• User aspects and documentation

• Compilation

• Integration of separately developed components

• Deployment of the system

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3. Implementation

4. Operation

2.

Design 5.

Maintenance

1.

Analysis

4.

Operation

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4. System Operation and maintenance

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Software life cycle – Course focus

3. Implementation

4. Operation

2.

Design 5.

Maintenance

1.

Analysis

Course focus

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Discussion -1

1. What is the difference between the following three terms: a) Software

b) System

c) Software system

2. According to the software life cycle, the specification of

functionalities of a system is performed by the system analyst in

the analysis phase. The specified functionalities guide the

development of system architectures in the designing phase. a) What problems do you think may happen due to the separation of

these two processes in different phases?

b) Do you think it is better to move the task for specification of

functionalities into designing phase?

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Visual Modeling with UML

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Topics to be covered

© Pearson education 2007

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Visualization of system models

Model: Focuses on visualizing fundamental

concepts of the intended system

UML: Unified modeling language


Types of conceptual models

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Use case view


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Use case modeling


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Requirements, actors and use cases


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Representation of actors


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Representation of use cases – Video store


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Use case diagram – Video store


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Use case diagrams forming a subject – Video store


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Documenting a use case


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Documenting a use case: Video store


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Activity view


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Activity modeling


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Identifying actions from a use case statement


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Activity diagrams


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Activity diagrams – Video store system (not complete)


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Structure view


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Class modeling


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Identification of classes: Some considerations


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Identifying classes


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Class diagram: Association relationship


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Class diagram: Aggregation relationship


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Class diagram: Generalization relationship


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Interaction view


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Sequence diagram


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Communication/collaboration diagram


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State machine view


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State machine modeling


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States, events and transitions


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QUESTION

Science

Ict 213 lecture 1