INTRO TO INFORMATION SYSTEMS DEVELOPMENT

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INTRO TO INFORMATION SYSTEMS DEVELOPMENT IS
340 BY CHANDRA S. AMARAVADI
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OVERVIEW

• Introduction
• System defined
• Characteristics of systems
• Good systems
• System development methodologies
• The Software development life cycle
• Methods of Analysis
• Design
• Design principles

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INTRODUCTION
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INTRODUCTION..
Information systems development is
primarily concerned with the process of
developing the software component of the
system. e.g. payroll, inventory, web-based
ordering etc.
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IMPORTANCE OF IS DEVELOPMENT

• Five million programmers
• IS needed for business operations
• One bank has 40,000 programs
• In many cases, IS -gt competitive advantage
• Most important part of the economy

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SYSTEM

• System any set of related elements (which are
  under consideration) working together towards the
  common purpose of transforming inputs into
  outputs
• Examples transportation network, education,
  building...
• In the IS context a system is any part (or
  whole) of the organization which satisfies the
  definition above
• Examples?

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CHARACTERISTICS OF SYSTEMS

• system can be open or closed
• have inputs, processes and outputs
• have a boundary
• have subsystems (subsystems share the same
  characteristics)
• have a life cycle

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WHAT IS A GOOD SYSTEM?
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DISCUSSION
How would you view a bank as a system?
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SYSTEM DEVELOPMENT METHODOLOGIES

• Prototyping - developing an initial version
  (model) of the system using quick dirty
  techniques and modifying it later.
• Traditional - go through a structured process of
  identifying requirements etc.
• Object oriented identifies objects and methods.
  The analysis focusses on identifying object
  relationships and programming the methods. (not
  discussed further)

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PROTYPING
User
Requirements
System
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THE CONVENTIONAL METHOD
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THE SOFTWARE DEVELOPMENT LIFE CYCLE
Systems go through a structured process of
development
PLANNING
ANALYSIS
DESIGN
IMPLEMENTATION
MAINTENANCE /SUPPORT
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SOFTWARE DEVELOPMENT LIFE CYCLE - SDLC

• Traditional
• Planning/feasibility study - scope and
  feasibility of the system
• Analysis - identify document the requirements
• Design - develop program/data/user interface
  structure to meet the requirements
• Implementation - coding/testing/installation of
  the program hiring of programmers/get HW/SW
• Maintenance/support - keep the system up to date
  with changes (business e.g. new accounting
  methods, new products HW/SW bugs, etc.)

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PLANNING
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ENTERPRISE ANALYSIS

• Interview Employees from top down
• Identify processes and information classes
• Process group of related activities
• Information class -- collection of information
• Develop process vs. info class matrix

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ENTERPRISE ANALYSIS MATRIX
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ANOTHER EA MATRIX
County Activity Tract Parcel Owner Unit
Land use X
Rds Bldgs X
Taxation X X
Waste disp.
Water supply
Cons. programs
Adapted from http//dlnt20.fsa.usda.gov/scdm/mode
l.htm
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ENTERPRISE ANALYSIS..

• Gives a broad understanding of processing
  requirements
• Can be used as a basis for database design

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METHODS OF ANALYSIS
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ANALYSIS METHODS
TECHNIQUES OF ANALYSIS

• Data Flow Diagramming (DFD)
• Data modelling
• Key Performance Indicators (a.k.a. CSFs)

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DATA FLOW DIAGRAMMING
1.0
process
Process order
Cust.
file
Invoice
data flow
Vendor
external entity
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FOR DISCUSSION
Classify each of the following as process,
external entity data store or information flow

• Review inventory
• A directory of manufacturers
• The securities and exchange commission
• Production plan
• A p.o. forwarded to a manager
• Verify a P.O.
• A transcript
• Sending a loan application
• Course schedule
• Prepare balance sheet

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VALID INVALID USAGE(DFDs)
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DFD GUIDELINES

• Connect processes first and add other details
• later
• Process names must be VN
• No restriction on naming of files/external
• entities
• Sub-systems must be separate
• Sub-systems are numbered using the Dewey
• system (e.g. 1.1, 1.2, 1.3 1.1.1, 1.1.2)
• The total of inputs and outputs of the
• subsystem must match with those of its
• immediate parent

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BALANCE A RVLE
1.0
1.1
1.2
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KEY PERFORMANCE INDICATORS

• A technique for identifying information
  requirements of executives
• KPIs are critical to the success of the firm
• KPIs are a.k.a Critical Success Factors (CSFs)

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KEY PERFORMANCE INDICATORS

• Identify KPIs
• key profit loss items
• key resources
• critical processes
• Identify information measures

Note KPIs are also known as Critical Success
Factors
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KPIs FOR A COMPANY LIKE CATERPILLAR
key profit loss items orders, order
quantities, raw material inventory, finished
goods inventory key resources raw
materials, senior engineers critical
processes engineering design sales marketing
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DISCUSSION
With what type of systems are KPIs associated
with?
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DESIGN
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DESIGN

• The purpose of design is to identify a program /
  interface / data structure to meet the
  requirements
• The design technique is referred to as Transform
  Analysis

What are the inputs to design?
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TRANSFORM ANALYSIS
(is a design technique)
a
d
b
f
e
c

• Identify Central Transform (C-T)
• Dangle DFD from C-T
• Result is a structure chart

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STRUCTURE CHART
d
a
b
c
e
.
f
.
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DESIGN PRINCIPLES
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DESIGN PRINCIPLES / TECHNIQUES
To design good systems it is necessary to follow
design principles

• Coupling
• Cohesion

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DESIGN PRINCIPLES / TECHNIQUES

• Coupling - the extent to which two (or more)
• modules are interconnected

"
Module A
Module B
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Module B
Module A
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COUPLING..
Module A
Module B
Call B
Go back to A
Go to B
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COHESION

• Cohesion - the extent to which elements in a
  module are related

Module1 read tax rate compute taxes tax rate
revenue move taxes to detail line write detail
line
Module2 write main headings write
subheadings write column headings compute taxes
tax rate revenue
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DISCUSSION QUESTIONS

• Which of the following are examples of systems?
  Motivation, Accounting, Competition, Core
  competency
• Do subsystems share the same characteristics as a
  system?
• Is KPI an analysis or a design technique?
• What is the design technique called?
• During what stage of the SDLC is coding done?
• What analysis technique is used to identify the
  information needs of top management?
• What are some KPIs for a computer manufacturer?
• What is Enterprise Analysis used for?
• What sort of benefits can you expect from a good
  information system?

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THANK YOU!