CHAPTER 8
Basic Information Systems
Concepts
8.1
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SYSTEMS VIEW
• FRAMEWORK FOR SEEING
INTERRELATIONSHIPS
• SYSTEM: Set of interrelated components
working together to achieve common
purpose
• INFORMATION SYSTEM (IS):
Collection of information technology,
procedures, & people that captures,
moves, manages, distributes data &
information
8.2
*
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GENERAL STRUCTURE OF SYSTEM
ENVIRONMENT
Output 1
Interface
Input 2 Interface
COMPONENT 2
Input 1
Interface
COMPONENT 3
BOUNDARY
8.3
COMPONENT 2
STORAGE 1
SYSTEM
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SYSTEM BOUNDARY
• DIVIDING LINE
• PLACED BASED ON THE PURPOSE:
Usually not a fixed line
• CONTROL OR REDESIGN WITHIN
THE BOUNDARY
• ENVIRONMENT OUTSIDE THE
BOUNDARY
*
8.4
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SYSTEM BOUNDARY
• WHAT CAN BE CONTROLLED:
External elements are constraints
• WHAT SCOPE MANAGEABLE
WITHIN GIVEN TIME PERIOD:
Complex systems take longer to design,
modify
• WHAT IS IMPACT OF BOUNDARY
CHANGE: Dynamic changes require
accommodation
8.5
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COMPONENT DECOMPOSITION
• BREAK SYSTEM INTO SUBSYSTEMS
• COMPONENTS OF SUBSYSTEM MAY
FORM MORE SUBSYSTEMS
• OFTEN SUBSYSTEMS ARE EASIER
TO UNDERSTAND, CREATE, MODIFY
*
8.6
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GOALS OF HIERARCHICAL
DECOMPOSITION
1. COPE WITH COMPLEXITY OF SYSTEM
2. ANALYZE OR CHANGE ONLY PART OF
SYSTEM
3. DESIGN, BUILD SUBSYSTEMS AT
DIFFERENT TIMES
4. DIRECT ATTENTION OF TARGET
AUDIENCE
5. ALLOW COMPONENTS TO OPERATE
INDEPENDENTLY
8.7
*
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FUNDAMENTAL COMPONENTS
OF ORGANIZATION
•
•
•
•
PEOPLE
INFORMATION TECHNOLOGY
BUSINESS PROCESSES
ORGANIZATIONAL STRUCTURE
EACH IMPACTS THE REST!
*
8.8
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DECISION MAKING
PROCESS
•
•
•
•
INTELLIGENCE: Search for needs, collect data
DESIGN: Generate alternatives, test feasibility
CHOICE: Select from alternatives
PERSUASION: Influencing others to accept &
follow chosen solution
• IMPLEMENTATION: Install solution on time,
within budget
• FOLLOW-UP: Monitor, modify, refine
CONSTANT FEEDBACK
8.9
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*
BUSINESS PROCESSES
A SET OF WORK ACTIVITIES &
RESOURCES
• IDENTIFY
• EVALUATE
• REDESIGN
USE INFORMATION TECHNOLOGY (IT)
TO BREAK RULES!
*
8.10
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EVALUATING A PROCESS X
• DOES X DEFINE FIRM TO CUSTOMERS,
EMPLOYEES, INVESTORS?
– YES: IDENTIFY
– NO: GO ON
• IS EXCELLING AT X CRITICAL TO
BUSINESS?
– YES: PRIORITY
– NO: GO ON
*
8.11
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EVALUATING A PROCESS X
• DOES X SUPPORT OTHER PROCESSES?
– YES: BACKGROUND
– NO: GO ON
• IS X CARRIED OUT ONLY BECAUSE IT IS
LEGALLY REQUIRED?
– YES: MANDATED
– NO: FOLKLORE > ABANDON
*
8.12
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BUSINESS PROCESS REDESIGN*
• START WITH “CLEAN SLATE”
• USE IT TO RADICALLY CHANGE
PROCESSES
• QUESTION ASSUMPTIONS & RULES
• ASK “WHY?”, “WHAT IF?”, “WHO
SAYS SO?”, “WHAT DO
CUSTOMERS THINK?”
*Hammer, 1990
*
8.13
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USING
IT TO BREAK DYSFUNCTIONAL
RULES*
Example #1
• OLD RULE:
Information can appear in only
one place at one time.
• DISRUPTIVE TECHNOLOGY:
Shared
databases
• NEW RULE:
Information can be used
simultaneously in many places
*Hammer & Chanmpy, 1993
8.14
*
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USING
IT TO BREAK DYSFUNCTIONAL
RULES*
Example #2
• OLD RULE:
Only EXPERTS do complex
work.
• DISRUPTIVE TECHNOLOGY:
Expert
systems
• NEW RULE:
Generalists can do complex
work like an EXPERT
*Hammer & Chanmpy, 1993
8.15
*
© Prentice Hall 2002
USING
IT TO BREAK DYSFUNCTIONAL
RULES*
Example #3
• OLD RULE: Field personnel need OFFICES to
receive, store, retrieve, and transmit information.
• DISRUPTIVE TECHNOLOGY: Portable and
home computers, modems, and wireless data
communication
• NEW RULE: Field personnel send and receive
information WHEREVER they are
*
*Hammer & Chanmpy, 1993
8.16
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PRINCIPLES FOR
REDESIGNING PROCESSES*
1. ORGANIZE AROUND OUTCOMES,
NOT TASKS
2. ASSIGN USERS OF OUTPUT TO
PERFORM PROCESS
3. INTEGRATE INFORMATION
PROCESSING INTO WORK THAT
PRODUCES INFORMATION
*
*Hammer, 1990
8.17
© Prentice Hall 2002
PRINCIPLES FOR
REDESIGNING PROCESSES*
4. CREATE VIRTUAL ENTERPRISE BY
TREATING GEOGRAPHICALLY
DISTRIBUTED RESOURCES AS
THOUGH THEY WERE
CENTRALIZED
5. LINK PARALLEL ACTIVITIES
INSTEAD OF INTEGRATING THEIR
RESULTS
*Hammer, 1990
*
8.18
© Prentice Hall 2002
PRINCIPLES FOR
REDESIGNING PROCESSES*
6. HAVE PEOPLE WHO DO WORK
MAKE DECISIONS, MONITOR
PROCESS BY BUILT-IN CONTROLS
*
*Hammer, 1990
8.19
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INFORMATION SYSTEMS LIFE
CYCLE
• DEFINITION PHASE: End-users &
analysts conduct analysis
• CONSTRUCTION: Use of structured
techniques, system development
methodology
• IMPLEMENTATION: Plan, test, train,
accept, monitor
*
8.20
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LOGIC TO-BE MODEL
SYMBOLS
ELEMENT SENDING OR RECEIVING
DATA. NAMES ARE NOUN LABELS
DATA IN MOTION BETWEEN ELEMENTS.
NAMES ARE NOUNS OR NUMBERS
PROCESSES WITH INPUT & OUTPUT.
NAMES ARE VERB PHRASES &
NUMBERS
DATA STORE WITH INPUT & OUTPUT.
NAMES ARE NOUNS & NUMBERS
8.21
*
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LOGIC TO-BE MODEL
PROCESSES
• IDENTIFY ENTITIES THAT SUPPLY, USE
SYSTEM INFORMATION
• DISTINGUISH PROCESSES FROM DATA
THEY USE OR PRODUCE
• EXPLICATES RULES AFFECTING
CHANGING DATA TO INFORMATION
• IDENTIFY LOGICAL RELATIONSHIPS
• PINPOINT DUPLICATE STORAGE,
MOVEMENT OF DATA
8.22
*
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WORK PROCESS FLOW SYMBOLS:
INPUT/OUTPUT
PUNCHED CARD
PROCESS
MAGNETIC TAPE
MANUAL OPERATION
ON-LINE STORAGE
DOCUMENT
DATABASE
ON-LINE INPUT
ON-LINE DISPLAY
8.23
TELECOMMUNICATIONS LINK
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PROGRAM FLOWCHART
SYMBOLS:
BEGIN OR
END
INPUT OR
OUTPUT
DIRECTION
SUBROUTINE
PROCESS
MANUAL
OPERATION
DECISION
CONNECTOR
8.24
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OBJECT-ORIENTED
TECHNIQUES
• KEY IDEA: Work with reusable objects
to speed up development!
TWO PRINCIPLES:
• ENCAPSULATION: Store data and
related operations together within objects
• INHERITANCE: Share common
characteristics between classes of objects
*
8.25
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OBJECT-ORIENTED
APPROACH
• DEFINE TASK: Search library of existing
objects useful to task
• PROCESS: Create bare-bones prototype,
test, provide critical feedback, repeat &
refine
• ELAPSED TIME: Can be weeks
*
8.26
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IT-RELATED RISKS
• ORGANIZATIONAL RISKS: From
changes in environment
• PERSONNEL RISKS: From loss of
expertise, system use (or non-use)
• SYSTEM PROJECT RISKS: From
project management deficiencies
• EXTERNAL SECURITY RISKS:
Criminal acts, natural disasters
8.27
*
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LIFE CYCLE CONTROLS
• DEFINITION & CONSTRUCTION:
– Methodology standards
– Validation rules & calculations
– System testing
• IMPLEMENTATION:
– Security
– Backup & recovery
– Auditing Roles
8.28
*
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CHAPTER 8
Basic Information Systems
Concepts
8.29
© Prentice Hall 2002