System Analysis and Design
System Analysis
- Mr. Ahmad Al-Ghoul
Learning Objectives





Describe systems analysis phase
activities and the end product of the
systems analysis phase
Describe the Unified Modeling Language
(UML)
Describe Functional Decomposition
Diagram ( FDD )
Explain why analysts using models
Describe CASE tools, objectives, and
types
Avicenna
System Analysis and Design
System Analysis
2
Learning Objectives



List and describe system requirements, including
outputs, inputs, processes, performance, and
controls
Explain the importance of scalability
Define total cost of ownership (TCO) and explain
the concept
Avicenna
System Analysis and Design
System Analysis
3
Introduction


The overall objective of the
systems analysis phase is to
understand the proposed system,
ensure that it will support business
requirement, and build solid
foundation of system development.
Systems Analysis Activities

Avicenna
The systems analysis phase includes
three main activates
 Requirements modeling
 Data and process modeling
 Development Strategies
System Analysis and Design
System Analysis
4
Systems Analysis Phase Overview

requirements Modeling

Requirements modeling involves

Fact finding

Avicenna
Describing the current system and identification of the
requirements for the new system which includes
 Outputs: electronic or printed information produced by the
system
 Inputs: data that enters the system
 Processes: the logical rules that are applied to transform
the data into information
 Performance: the system characteristics, speed, volume,
capacity, availability, and reliability
 Security: hardware, software, and procedural controls that
protect the system and data from internal or external
threats
System Analysis and Design
System Analysis
5
Systems Analysis Phase Overview

Data and process modeling


Represent graphically system data and process using
various techniques.
Development Strategies


Evaluation of alternative solutions
Preparation of the system requirements document

Avicenna
System requirements document is an overall design for the
new system
System Analysis and Design
System Analysis
6
Systems Analysis Phase Overview

Modeling tools and techniques


Avicenna
Modeling involves graphical methods and nontechnical language that represent the system
at various stages of development
There are various tools to describe business
processes, requirements, and user interaction
with the system
System Analysis and Design
System Analysis
7
Modeling Tools and Techniques

Analysts using models to:
Concentrate on important features of the system,
pay less attention to less important ones;
 Able to respond to changes or changes in user’s
requirements with low cost and risk;
 Properly understand users’ environment and write
documents in the same way that designers and
programmers construct the system.

Avicenna
System Analysis and Design
System Analysis
8
Modeling Tools and Techniques

CASE Tools ( computer-aided software engineering )




Avicenna
CASE tools have been developed for internal use and for sale by
several firms, including Oracle ( Designer), IBM ( Rational Rose )
Automated software tool used by systems analysts to develop
information systems
Used to support or automate activities throughout the systems
development life cycle (SDLC)
CASE tools include diagramming tools for data flow diagrams
and other graphical aids, screen and report design tools, and
other special-purpose tools
System Analysis and Design
System Analysis
9
Modeling Tools and Techniques

Objectives of CASE










Avicenna
Improve quality of systems developed
Increase speed of development and design
Ease and improve testing process through automated checking
Improve integration of development activities via common
methodologies
Improve quality and completeness of documentation
Help standardize the development process
Improve project management
Simply program maintenance
Promote reusability
Improve software portability
System Analysis and Design
System Analysis
10
Modeling Tools and Techniques

Functional Decomposition Diagram ( FDD )





Avicenna
A top-down representation of a function or process
A function diagram only shows what to do not how to
do.
FDD is a process of division, from a higher function
to appropriate smaller functions.
FDD need to be presented clearly, simply, exactly, and
fully .
FDD can be used at several stages of systems
development
System Analysis and Design
System Analysis
11
Modeling Tools and Techniques
Four-level functional decomposition diagram (FDD) of a library system.
Avicenna
System Analysis and Design
System Analysis
12
Modeling Tools and Techniques

Unified Modeling Language ( UML )





Avicenna
UML is a method of visualizing and
documenting software systems design
UML uses object-oriented design concepts
UML is independent of any specific
programming language
UML used to describe business processes and
requirements generally
UML provides various graphical tools
System Analysis and Design
System Analysis
13
System Requirements Checklist

System Requirements Checklist


Avicenna
System developers must identify and describe
all system requirements
System Requirements are a characteristics or
features that must be included in an
information system to satisfy business
requirements and be acceptable to users
System Analysis and Design
System Analysis
14
System Requirements Checklist

Five categories of system requirements






Outputs
Inputs
Processes
Performance
Controls
In the next slides some examples of
system requirements
Avicenna
System Analysis and Design
System Analysis
15
System Requirements Checklist

Outputs


The Web site must report online volume
statistics every four hours, and hourly during
peak periods
Inputs

Avicenna
The department head must enter overtime
hours on a separate screen
System Analysis and Design
System Analysis
16
System Requirements Checklist

Processes


Performance


The student records system must calculate
the GPA at the end of each semester
Response time must not exceed four seconds
Controls

Avicenna
An employee record must be added, changed,
or deleted only by a member of the human
resources department
System Analysis and Design
System Analysis
17
Future Growth, Costs, and Benefits

In addition to the system requirements,
system analyst must consider
Scalability
 Total Cost of Ownership

Avicenna
System Analysis and Design
System Analysis
18
Future Growth, Costs, and Benefits

Scalability



Avicenna
System’s ability to handle increased business
volume and transactions in the future
A scalable system offers a better return on
the initial investment
To evaluate, you need information about
projected future volume for all outputs,
inputs, and processes
System Analysis and Design
System Analysis
19
Future Growth, Costs, and Benefits

Total cost of ownership (TCO)




Avicenna
A number that is used in assessing costs, which
includes ongoing support and maintenance costs, as
well as acquisition costs.
TCO especially important if the development team is
evaluating several alternatives
One problem is that cost estimates tend to
understate indirect costs
Systems analysts should try to identify indirect costs
and include them in TCO estimates
System Analysis and Design
System Analysis
20
Sequence Summary







The systems analysis phase includes three activities:
requirements modeling, data and process modeling, and
consideration of development strategies
The main objective is to understand the proposed project and
build a solid foundation for the systems design phase
You identify the business-related requirements for the new
information system, including outputs, inputs, processes,
performance, and controls
You consider scalability to ensure that the system can support
future growth and expansion
You also estimate total cost of ownership (TCO) to identify all
costs, including indirect costs
UML is a method of visualizing and documenting software
systems design
CASE tools are automated software tool used by systems
analysts to develop information systems
Avicenna
System Analysis and Design
System Analysis
21
Sequence Summary

In this Sequence we have
 Described the systems analysis phase including three
activities: requirements modeling, data and process
modeling, and consideration of development strategies
 Explained the main analysis objective that is to understand
the proposed project and build a solid foundation for the
systems design phase
 identified the business-related requirements for the new
information system, including outputs, inputs, processes,
performance, and controls
 Identified the fact-finding process includes interviewing,
document review, observation, questionnaires, sampling, and
research
 Described the Unified Modeling Language (UML)
 Described Functional Decomposition Diagram
( FDD )
 Explained why analysts using models
 Describe CASE tools, objectives, and types
Avicenna
System Analysis and Design
System Analysis
22
Reference
[1] System Analysis and Design, Sixth Edition
Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. Rosenblatt
Publisher: SHELLY CASHMAN SEWIES.
[2] Modern Systems Analysis and Design Third Edition
Authors: Jeffrey A. Hoffer , Joey F. George, Joseph S. Valacich
Publisher: prentice hall
Avicenna
System Analysis and Design
System Analysis
23
Descargar

Slide 1