CH12-Exploring Information System Development

Chapter 12
Exploring Information System
Development

Discovering
Computers 2012
Your Interactive Guide
to the Digital World

Objectives Overview

Discuss the importance of
project management,
Define system development
Identify the guidelines for feasibility assessment,
and list the system
system development documentation, and data
development phases
and information gathering
techniques

Explain the activities Discuss the purpose of the
Describe the various tools
performed in the planning activities performed in the
used in process modeling
phase analysis phase

See Page 619 2
Discovering Computers 2012: Chapter 12
for Detailed Objectives

Objectives Overview

Recognize the develop
Describe the various Explain the activities
programs activity is
tools used in object performed in the
part of system
modeling design phase
development

Discuss the purpose of
Discuss the activities the activities
performed in the performed in the
implementation phase operation, support, and
security phase

See Page 619 3
Discovering Computers 2012: Chapter 12
for Detailed Objectives

What is System Development?

System development is a set of activities
used to build an information system
An information
system (IS) is a System development
A system is a set of collection of activities are grouped
components that hardware, software, into phases,
interact to achieve a data, people, and collectively called the
common goal procedures that work system development
together to produce life cycle (SDLC)
quality information

Page 620 Discovering Computers 2012: Chapter 12 4


Pages 620 – 621 Discovering Computers 2012: Chapter 12 5
Figure 12-1


• System development should follow three general
guidelines:

Group activities or tasks into phases

Involve users

Define standards



• System development should involve representatives from each
department in which the proposed system will be used

Figure 12-2


• Project management is the process of planning,
scheduling, and then controlling the activities during
system development
• To plan and schedule a project efficiently, the project
leader identifies:
Required Time estimates
Project scope
activities for each activity

Activities that
Cost estimates Order of
can take place at
for each activity activities
the same time


A popular tool
used to plan
and schedule
the time
relationships
among project
activities is a
Gantt chart

Figure 12-3a


A PERT chart
also can be
used for
planning and
scheduling time

Figure 12-3b


• Feasibility is a measure of how suitable the
development of a system will be to the
organization

Operational Schedule Technical Economic
feasibility feasibility feasibility feasibility

Pages 624 - 625 Discovering Computers 2012: Chapter 12 11


• Documentation is the collection and
summarization of data and information
– A project notebook contains all documentation for a
single project
• Users and IT professionals refer to existing
documentation when working with and modifying
current systems



• During system development, members of the project
team gather data and information using several
techniques

Review
Observe Survey
documentation

Interview JAD Sessions Research

Figure 12-4

Who Initiates a System
Development Project?

A user may request a new or modified system

Organizations may want to improve hardware, software, or other
technology

Situations beyond an organization’s control might require a change

Management might mandate a change

A user may request a new or modified information system using a request
for system services or a project request


Who Initiates a System
Development Project?

Figure 12-5

Planning Phase

• The planning phase for a project begins when the
steering committee receives a project request
• Four major activities are performed:

Review and Form a project
Prioritize the Allocate
approve the development
project requests resources
project requests team


Analysis Phase

• The analysis phase consists of two major
activities:
Conduct a preliminary Perform detailed
investigation analysis
• Determines and • Study how the current
defines the exact system works
nature of the problem • Determine the users’
or improvement wants, needs, and
• Interview the user who requirements
submitted the request • Recommend a solution


Analysis Phase

Figure 12-6

Analysis Phase

• Process modeling (structured analysis and design) is an
analysis and design technique that describes processes
that transform inputs into outputs
Entity-
Data flow
relationship
diagrams
diagrams

Project
dictionary


Analysis Phase

• An entity-relationship
diagram (ERD) is a tool
that graphically shows
the connections among
entities in a system
• Entities are objects in
the system that have
data

Figure 12-7

Analysis Phase

• A data flow diagram
(DFD) is a tool that
graphically shows the
flow of data in a system
– Data flows
– Processes
– Data stores
– Sources

Figure 12-8

Analysis Phase

• The project dictionary contains all the
documentation and deliverables of a project
• Structured English is a
style of writing that
describes the steps in
a process

Figure 12-9

Analysis Phase

A decision table is a table that
lists a variety of conditions
and the actions that
correspond to each condition

A decision tree also shows
conditions and actions, but it
shows them graphically


Analysis Phase

Decision table Decision tree

Figures 12-10 – 12-11

Analysis Phase

• The data dictionary stores the data item’s name,
description, and other details about each data
item

Figure 12-12

Analysis Phase

• Object modeling combines the data with the processes
that act on that data into a single unit, called an object
• UML (Unified Modeling Language) has been adopted as a
standard notation for object modeling and development
– UML includes 13 different diagrams
– Two diagrams include:

Use case
Class diagram
diagram


Analysis Phase

• A use case diagram
graphically shows how
actors (users) interact
with the information
system
• Diagrams are
considered easy to
understand

Figure 12-13

Analysis Phase

• A class diagram
graphically shows
classes and subclasses
in a system
• Each class can have one
or more subclasses
• Subclasses use
inheritance to inherit
methods and attributes
of higher levels

Figure 12-14

Analysis Phase

• The system proposal assesses the feasibility of
each alternative solution
• The steering committee discusses the system
proposal and decides which alternative to pursue

Packaged Custom
Outsourcing
software software


Design Phase

• The design phase consists of two major activities

Develop all of the
Acquire hardware details of the new
and software or modified
information system


Design Phase

• To acquire the necessary hardware and software:

Solicit vendor
Make a decision
• Use research proposals • Various techniques
techniques such as are used to
e-zines • RFQ, RFP, or RFI is determine the best • Systems analyst
sent to potential proposal makes
vendors or VARs recommendation to
steering committee
Identify technical Test and evaluate
specifications vendor proposals


Design Phase

• The next step is to develop detailed design
specifications
– Sometimes called a physical design

Input and
Database Program
output
design design
design


Design Phase

• Systems analysts typically develop two types of
designs for each input and output
Mockup Layout chart

Figures 12-18 – 12-19

Design Phase

• A prototype (proof of concept) is a working model
of the proposed system
– Prototypes have inadequate or missing documentation
– Users tend to embrace the prototype as a final system
– Should not eliminate or replace activities


Design Phase

• Computer-aided software engineering (CASE)
tools are designed to support one or more
activities of system development
• CASE tools sometimes contain the following tools:
Project
Graphics Prototyping
repository

Quality Code
Housekeeping
assurance generator


Design Phase

Figure 12-20

Design Phase

• Many people should review the detailed design
specifications
• An inspection is a formal review of any system
development deliverable
– A team examines the deliverables to identify errors


Implementation Phase

• The purpose of the implementation phase is to
construct the new or modified system and then
deliver it

Install and Convert to
Develop
test the new Train users the new
programs
system system



• The program development life cycle follows these
steps: • Analyze the requirements
1

2 • Design the solution
3 • Validate the design
4 • Implement the design
5 • Test the solution
6 • Document the solution


• Various tests should be performed on the new
system
Integration Acceptance
Unit test Systems test
test test
• Verifies that • Verifies that • Verifies that • Checks the
each all programs an new system
individual in an application to ensure
program or application works with that it works
object works work other with actual
by itself together applications data
properly



• Training involves showing users exactly how they
will use the new hardware and software in the
system
– One-on-one sessions
– Classroom-style lectures
– Web-based training

Figure 12-21


• One or more of four conversion strategies can be
used to change from the old system to the new
system

Figure 12-22

Operation, Support, and Security Phase

• The purpose of the operation, support, and
security phase is to provide ongoing assistance for
an information system and its users after the
system is implemented

Perform Monitor
Assess system
maintenance system
security
activities performance


Operation, Support, and Security Phase

• A computer security plan should do the following:

For each risk,
Identify all identify the
Identify all
security risks safeguards that
information
that may cause exist to detect,
assets of an
an information prevent, and
organization
asset loss recover from a
loss


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Discovering Computers 2012: Chapter 12 45

Summary

System Guidelines for
development system
phases development

Activities
Activities that occur
performed during
during system
each system
development
development phase

Chapter 12
Exploring Information System
Development

Discovering
Computers 2012
Your Interactive Guide
to the Digital World
Chapter 12 Complete

CH12-Exploring Information System Development

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