1. Stumpf and Teague Object-Oriented Systems Analysis and Design with UML.
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2. Stumpf and Teague Object-Oriented Systems Analysis and Design with UML.
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3. Learning Objectives
Explain how systems thinking helps address the complexity of developing an information processing system.
Define a system and identify the function, components, and structure of familiar systems.
Understand the relationship between a system and its environment or context.
Explain the role of an interface.
Give examples of information system components which perform the functions of transformation, transmission, and storage.
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4. Learning Objectives (continued)
Explain the difference between essential and implementation descriptions of a system.
Describe some of the major roles of information in a business organization.
Explain the major steps in a problem-solving or decision-making process and how systems analysis can be understood as problem solving.
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5. Overview
Systems analysis is a discipline which analyzes problems, estimates the consequences of various courses of action, and recommends what action to take to solve problems.
Information systems analysis seeks to improve information systems so that they provide better support for the business activities of an organization.
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6. Overview (continued)
Humans cope with complexity by thinking in terms of systems. A system organizes its components into a structure and is separated from its environment by a system boundary.
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7. Overview (continued)
System analysts work with abstract models in order to:
Understand existing systems
Simulate system behavior
Describe the requirements for a new system
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8. Overview (continued)
In general, information systems perform three functions:
Transmission of information
Storage of information
Transformation of information
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9. Overview (continued)
The important overall function of an information processing system is to respond to what happens in the outside world by transforming inputs into the desired outputs.
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10. Overview (continued)
System analysts help solve business problems by applying information technology not only to production and service functions but also to improved monitoring, control, and decision support.
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11. Coping with Complexity
In order to structure and simplify complexity, we:
Limit the extent of our interest
Select only the important or essential features
Break up the complexity into manageable small pieces
Examine things iteratively
Review and refine in order to improve
Use visual thinking whenever we can
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12. What Is a System?
A system is an interrelated set of components which are viewed as a whole.
It has:
Components – its basic parts
Structure – how the components are organized
Function – what the system does
Objectives – the human purposes served by the system
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13. System Structures Hierarchical (Tree) Matrix (Grid) Network
Each component is subordinate to exactly one other component.
Components can be nested.
Matrix (Grid)
Each component, or cell, is determined by a combination of two or more factors.
Network
Nodes or points connected by arcs or links.
Arcs may permit flows, as in a transportation or telecommunication network.
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14. Hierarchical System Structure.
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15. Matrix System Structure.
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16. Network System Structure.
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17. A System and Its Environment
A system has a boundary which separates it from its environment.
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18. Interfaces
An interface describes an interaction or connection between a system and its environment, or between subsystems.
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19. System Models
A system model is an abstract, selective system description used to:
Understand the system
Study system behavior
Communicate our understanding of the system to others
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20. System Models (continued)
A representation of a model is a graphical or physical way of displaying the components and relationships in the model.
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21. Generating a System Model
We generate a system model through:
Aggregation: Assembling it out of a set of elementary components, or primitives, through synthesis – a
bottom-up process.
Decomposition: Partitioning the whole into its constituent parts through analysis – a top-down process.
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22. Functions of an Information Processing System
Communication
Moves or transports information from place to place
Storage
Records and saves information for future use
Transformation
Changes information content by deriving outputs from inputs using a known, defined procedure
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23. Automated Information Processing Systems
Hardware
Data capture and display devices
Processing units
Memory (volatile and permanent)
Channels for information flow
Software
Operating system and related software
Communications software
Application software
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24. System Descriptions Implementation Descriptions
Dependent on a specific implementation or technology
Sometimes called physical descriptions
Essential Descriptions
Independent of a specific implementation or technology
Sometimes called logical descriptions
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25. System Descriptions (continued)
Implementation
Description
Non-essential
Shows form
Concrete
Implementation- dependent
Technology- dependent
Essential
Description
Shows content
Abstract
Implementation independent
Technology- independent
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26. A Systems View of Business
Industrial or manufacturing businesses, which produce goods
Service businesses, which do not produce goods
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27. A Systems View of Business (continued).
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28. A Systems View of Business (continued).
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29. Roles of Information in Business
It helps carry out the production and service functions of the organization.
It measures and monitors the performance of these primary business functions and other supporting functions.
It helps the organization control its operations to meet performance targets.
It supports management decisions to improve the business by modifying the organization or changing its objectives.
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30. The Problem-Solving Process
Identify the problem.
Generate possible solutions.
By applying constraints, eliminate proposals which do not solve the problem.
Evaluate the expected performance or behavior of each proposed solution.
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31. The Problem-Solving Process (continued)
Using the criteria, compare the alternatives to select the best solution.
Plan how to implement the selected solution.
Implement the solution.
Evaluate the performance of the solution after its implementation.
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32. Summary
System analysts apply information technology to business problems and systems in order to improve production and services as well as provide improved monitoring, control, and managerial decisions.
Basic systems concepts and models help analysts succeed in addressing the complexity of real-world systems.
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