1. CHAPTER 9 (part a) BASIC INFORMATION SYSTEMS CONCEPTS

2. THE SYSTEMS VIEW Systems thinking is: a discipline for seeing wholes
a framework for seeing interrelationships rather than things
an antidote to feeling of helplessness when dealing with complexity
Peter Senge (1990)
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3. THE SYSTEMS VIEW What Is a System?
System – a set of interrelated components that must work together to achieve some common purpose
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4. THE SYSTEMS VIEW What Is a System?
All components are there … but they don’t work well together!
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Figure 9.1 An Example of Poor Design
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5. THE SYSTEMS VIEW What Is a System?
System – a set of interrelated components that must work together to achieve some common purpose
Information System – the collection of IT, procedures, and people responsible for the capture, movement, management, and distribution of data and information
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6. THE SYSTEMS VIEW Seven Key System Elements Boundary Environment Inputs
Outputs
Components
Interfaces
Storage
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Figure 9.2 General Structure of a System
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7. Page 357 Figure 9.3 System Component Examples
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Figure 9.3 System Component Examples
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8. THE SYSTEMS VIEW System boundary depends on: What can be controlled
Seven Key System Elements – System Boundary
System boundary depends on:
What can be controlled
What scope is manageable within a given time period
The impact of a boundary change
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9. THE SYSTEMS VIEW
Seven Key System Elements – Component Decomposition
A component of a system is also called a subsystem or module
Hierarchical decomposition – the process of breaking down a system into successive levels of subsystems, each showing more detail
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10. THE SYSTEMS VIEW Goals of hierarchical decomposition:
Seven Key System Elements – Component Decomposition
Goals of hierarchical decomposition:
To cope with system complexity
To analyze or change part of the system
To design and build each subsystem at different times
To direct the attention of a target audience
To allow system components to operate more independently
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11. THE SYSTEMS VIEW Functions of an interface:
Seven Key System Elements – Interfaces
Interface – point of contact between a system and its environment or between two subsystems
Functions of an interface:
Filtering
Coding/decoding
Error detection and correction
Buffer
Security
Summarizing
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12. THE SYSTEMS VIEW
Seven Key System Elements – Interfaces
Interfaces built between two preexisting systems are called bridges
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13. THE SYSTEMS VIEW Possible objective of an interface:
Seven Key System Elements – Interfaces
Possible objective of an interface:
System decoupling – changing two system components so that modifying one does not necessarily require modifying the other
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14. Page 358 Figure 9.4 Sales Summary Reporting System
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Figure Sales Summary Reporting System
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15. Page 359 Figure 9.4 Sales Summary Reporting Subsystem
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Figure 9.4 Sales Summary Reporting Subsystem
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16. THE SYSTEMS VIEW Organizations as Systems How does a change in one
affect the others?
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Figure 9.5 Fundamental Components
of an Organization
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17. THE SYSTEMS VIEW Fundamental principles: Systems Analysis and Design
Systems analysis and design (SA&D) – a process used in developing new information systems based on a systems approach to problem solving
Fundamental principles:
Choose an appropriate scope (boundary selection)
Logical before physical (what before how)
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18. THE SYSTEMS VIEW Recommended problem-solving steps:
Systems Analysis and Design
Recommended problem-solving steps:
Problem (or system) is a set of problems that must be broken down into smaller, more manageable problems
Single solution is not always obvious to all – alternatives should be generated and considered
Understanding of problem changes, so reassess commitment to solution at various stages
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19. BUSINESS PROCESSES
Business process – a set of work activities and resources
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20. evaluate a business process
One way managers can
evaluate a business process
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Figure Evaluating Business Processes
(Keen, 1997)
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21. BUSINESS PROCESSES Business Process Redesign
Business process reengineering (BPR) – radical business redesign initiatives that attempt to achieve dramatic improvements in business processes by questioning the assumptions, or business rules, that underlie the organization’s structures and procedures
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22. BUSINESS PROCESSES Six principles for redesigning business processes:
Business Process Redesign
Six principles for redesigning business processes:
Organize business processes around outcomes, not tasks
Assign those who use the output to perform the process
Integrate information processing into the work that produces the information
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23. BUSINESS PROCESSES Six principles for redesigning business processes:
Business Process Redesign
Six principles for redesigning business processes:
Create a virtual enterprise by treating geographically distributed resources as though they were centralized
Link parallel activities instead of integrating their results
Have the people who do the work make all the decisions, and let controls built into the system monitor the process
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24. BUSINESS PROCESSES Business Process Redesign Page 363
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Figure How IT Enables New Ways to Work
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25. PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
The Information Systems Life Cycle
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Figure Generic Systems Life Cycle
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26. PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
The Information Systems Life Cycle
Definition Phase:
End user and systems analysts conduct analysis of current system and business processes
Analysis is:
Process-oriented
Data-oriented
Business case generated and solution chosen
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27. PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
The Information Systems Life Cycle
Construction Phase:
System designed, built, and tested
System logically described, then physically
Technology chosen
Programs, inputs, and outputs designed
Software programmed and tested
User acceptance testing conducted
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28. PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
The Information Systems Life Cycle
Implementation Phase:
Business managers and IS professionals install new system
Data and procedures from old system converted
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29. PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
Structured Techniques for Life Cycle Development
System development methodology – framework consisting of guidelines, tools, and techniques for managing skills to address the business issue
Consists of processes, tools, techniques for developing systems
Prescribe who participates, roles, development stages and decision points, and formats for documentation
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30. PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
Structured Techniques for Life Cycle Development
Structured techniques – tools to document system needs, requirements, functional features, dependencies, and design decisions
Procedural-oriented
Most common
Include data-oriented, sequential, process-oriented activities
Object-oriented
Newer approach
Often used for GUIs and multimedia applications
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31. PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
Procedural-Oriented Techniques
Provides a baseline for the new system
Includes both logical and physical models
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Figure Three-Step Modeling Approach
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32. PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
Procedural-Oriented Techniques
Critical appraisal of existing work processes to:
Identify major subprocesses, entities, and interactions
Separate processing from data flow
Capture relationships between data elements
Determine entities and processes within scope
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Figure Three-Step Modeling Approach
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33. PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
Procedural-Oriented Techniques
Conducted by IS specialists
Maps logical requirements to available technology
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Figure Three-Step Modeling Approach
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