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CHAPTER 9 (part a) B ASIC I NFORMATION S YSTEMS C ONCEPTS

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).

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CHAPTER 9 (part a) B ASIC I NFORMATION S YSTEMS C ONCEPTS

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  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) Page 355

  3. THE SYSTEMS VIEW What Is a System? System – a set of interrelated components that must work together to achieve some common purpose Page 355

  4. THE SYSTEMS VIEW What Is a System? All components are there … but they don’t work well together! Page 355 Figure 9.1 An Example of Poor Design

  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 Page 355-356

  6. THE SYSTEMS VIEW Seven Key System Elements • Boundary • Environment • Inputs • Outputs • Components • Interfaces • Storage Page 356 Figure 9.2 General Structure of a System

  7. Page 357 Figure 9.3 System Component Examples

  8. THE SYSTEMS VIEW 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 Page 357

  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 Page 357

  10. THE SYSTEMS VIEW 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 Page 357

  11. THE SYSTEMS VIEW 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 Page 357-358

  12. THE SYSTEMS VIEW Seven Key System Elements – Interfaces Interfaces built between two preexisting systems are called bridges Page 359

  13. THE SYSTEMS VIEW 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 Page 359

  14. Page 358 Figure 9.4 Sales Summary Reporting System

  15. Page 359 Figure 9.4 Sales Summary Reporting Subsystem

  16. THE SYSTEMS VIEW Organizations as Systems How does a change in one affect the others? Figure 9.5 Fundamental Components of an Organization Page 359

  17. THE SYSTEMS VIEW 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) Page 360

  18. THE SYSTEMS VIEW 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 Page 360

  19. BUSINESS PROCESSES Business process – a set of work activities and resources Page 361

  20. One way managers can evaluate a business process Figure 9.6 Evaluating Business Processes (Keen, 1997) Page 361

  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 Page 362

  22. 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 Page 363

  23. 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 Page 362

  24. BUSINESS PROCESSES Business Process Redesign Page 363 Figure 9.7 How IT Enables New Ways to Work

  25. PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS The Information Systems Life Cycle Page 364 Figure 9.8 Generic Systems Life Cycle

  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 Page 364

  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 Page 364

  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 Page 364

  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 Page 365

  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 Page 365

  31. PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS Procedural-Oriented Techniques • Provides a baseline for the new system • Includes both logical and physical models Page 365 Figure 9.9 Three-Step Modeling Approach

  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 Page 365 Figure 9.9 Three-Step Modeling Approach

  33. PROCESSES AND TECHNIQUES TO DELIVER INFORMATION SYSTEMS Procedural-Oriented Techniques • Conducted by IS specialists • Maps logical requirements to available technology Page 365 Figure 9.9 Three-Step Modeling Approach

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