chapter 9 (part a) b asic i nformation s ystems c oncepts
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CHAPTER 9 (part a) B ASIC I NFORMATION S YSTEMS C ONCEPTS. T HE S YSTEMS V IEW. 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). - PowerPoint PPT PresentationTRANSCRIPT
E. Wainright Martin Carol V. Brown Daniel W. DeHayesJeffrey A. Hoffer William C. Perkins
MANAGINGMANAGINGINFORMATIONINFORMATIONTECHNOLOGYTECHNOLOGY
FIFTH EDITION
CHAPTER 9 (part a)
BASIC INFORMATION SYSTEMS CONCEPTS
© 2005 Pearson Prentice-Hall Chapter 9 - 2
THE SYSTEMS VIEW
Systems thinking is:a discipline for seeing wholesa framework for seeing interrelationships
rather than thingsan antidote to feeling of helplessness when
dealing with complexity
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Peter Senge (1990)
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System – a set of interrelated components that must work together to achieve some common purpose
THE SYSTEMS VIEWWhat Is a System?
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THE SYSTEMS VIEW
All components are there … but they don’t work well together!
Figure 9.1 An Example of Poor Design
What Is a System?
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System – a set of interrelated components that must work together to achieve some common purpose
THE SYSTEMS VIEWWhat Is a System?
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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Seven Key System Elements
THE SYSTEMS VIEW
1. Boundary
2. Environment
3. Inputs
4. Outputs
5. Components
6. Interfaces
7. Storage
Figure 9.2 General Structure of a System
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Seven Key System Elements – System Boundary
System boundary depends on:
1. What can be controlled
2. What scope is manageable within a given time period
3. The impact of a boundary change
THE SYSTEMS VIEW
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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
THE SYSTEMS VIEW
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Seven Key System Elements – Component Decomposition
Goals of hierarchical decomposition:
1. To cope with system complexity
2. To analyze or change part of the system
3. To design and build each subsystem at different times
4. To direct the attention of a target audience
5. To allow system components to operate more independently
THE SYSTEMS VIEW
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Seven Key System Elements – Interfaces
Functions of an interface: Filtering Coding/decoding Error detection and correction Buffer Security Summarizing
Interface – point of contact between a system and its environment or between two subsystems
THE SYSTEMS VIEW
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Seven Key System Elements – Interfaces
Interfaces built between two preexisting systems are called bridges
THE SYSTEMS VIEW
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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
THE SYSTEMS VIEW
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© 2005 Pearson Prentice-Hall Chapter 9 - 15 Page 359Figure 9.4 Sales Summary Reporting Subsystem
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Organizations as Systems
Figure 9.5 Fundamental Components of an Organization
How does a change in oneaffect the others?
THE SYSTEMS VIEW
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Systems Analysis and Design
Fundamental principles: Choose an appropriate scope (boundary selection) Logical before physical (what before how)
Systems analysis and design (SA&D) – a process used in developing new information systems based on a systems approach to problem solving
THE SYSTEMS VIEW
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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
THE SYSTEMS VIEW
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Business process – a set of work activities and resources
BUSINESS PROCESSES
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One way managers can evaluate a business process
Figure 9.6 Evaluating Business Processes (Keen, 1997)
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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
BUSINESS PROCESSESBusiness Process Redesign
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BUSINESS PROCESSESBusiness Process Redesign
Six principles for redesigning business processes:
1. Organize business processes around outcomes, not tasks
2. Assign those who use the output to perform the process
3. Integrate information processing into the work that produces the information
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BUSINESS PROCESSESBusiness Process Redesign
Six principles for redesigning business processes:
4. Create a virtual enterprise by treating geographically distributed resources as though they were centralized
5. Link parallel activities instead of integrating their results
6. 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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BUSINESS PROCESSESBusiness Process Redesign
Figure 9.7 How IT Enables New Ways to Work
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PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMSThe Information Systems Life Cycle
Figure 9.8 Generic Systems Life Cycle
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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
PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMSThe Information Systems Life Cycle
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PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
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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
The Information Systems Life Cycle
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PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
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Implementation Phase: Business managers and IS professionals
install new system
Data and procedures from old system converted
The Information Systems Life Cycle
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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
PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMSStructured Techniques for Life Cycle Development
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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
PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
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Procedural-Oriented Techniques
Provides a baseline for the new system Includes both logical and physical models
Figure 9.9 Three-Step Modeling Approach
PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
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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
Figure 9.9 Three-Step Modeling Approach
PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS
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Procedural-Oriented Techniques
Conducted by IS specialists Maps logical requirements to available technology
Figure 9.9 Three-Step Modeling Approach
PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS