chap3 seq5.ppt

System Analysis
- Mr. Ahmad Al-Ghoul
System Analysis and
Design

Avicenna
System Analysis and Design
System Analysis 2
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

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System Analysis 3
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

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System Analysis 4
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
 The systems analysis phase includes
three main activates
 Requirements modeling
 Data and process modeling
 Development Strategies

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System Analysis 5
Systems Analysis Phase Overview
 requirements Modeling
 Requirements modeling involves
 Fact finding
 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

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System Analysis 6
 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
 System requirements document is an overall design for the
new system

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System Analysis 7
 Modeling tools and techniques
 Modeling involves graphical methods and non-
technical 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

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System Analysis 8
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.

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System Analysis 9
 CASE Tools ( computer-aided software engineering )
 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

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System Analysis 10
 Objectives of CASE
 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

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System Analysis 11
 Functional Decomposition Diagram ( FDD )
 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

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System Analysis 12
Four-level functional decomposition diagram (FDD) of a library system.

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System Analysis 13
 Unified Modeling Language ( UML )
 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

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System Analysis 14
System Requirements Checklist
 System Requirements Checklist
 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

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System Analysis 15
 Five categories of system requirements
 Outputs
 Inputs
 Processes
 Performance
 Controls
 In the next slides some examples of
system requirements

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System Analysis 16
 Outputs
 The Web site must report online volume
statistics every four hours, and hourly during
peak periods
 Inputs
 The department head must enter overtime
hours on a separate screen

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System Analysis 17
 Processes
 The student records system must calculate
the GPA at the end of each semester
 Performance
 Response time must not exceed four seconds
 Controls
 An employee record must be added, changed,
or deleted only by a member of the human
resources department

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System Analysis 18
Future Growth, Costs, and Benefits
 In addition to the system requirements,
system analyst must consider
 Scalability
 Total Cost of Ownership

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System Analysis 19
 Scalability
 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

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System Analysis 20
 Total cost of ownership (TCO)
 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

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System Analysis 21
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

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System Analysis 22
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 23
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

chap3 seq5.ppt

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