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Information Systems Analysis and Design

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Title: Information Systems Analysis and Design


1
Information SystemsAnalysis and Design
  • Myriam Lewkowicz

2
Outline
  1. Information Systems the big picture
  2. Information Systems for competitive advantage
  3. Organizational Information Systems
  4. Entreprise-Wide Information Systems
  5. Information Systems Development Acquisition
  6. Managing the Information Systems Project
  7. Systems Planning
  8. Determining System Requirements
  9. Structuring System Requirements Process
    Modeling
  10. Structuring System Requirements Conceptual Data
    Modeling
  11. Object Oriented Analysis and Design
  12. Designing the Human Interface
  13. Systems Implementation and Operation

3
Chapter 1Information SystemsThe Big Picture
4
Chapter 1 Objectives
  • Understand the term information systems (IS)
  • Understand IS components
  • Technology, people, organizations
  • Understand IS career opportunities
  • Understand types of information systems
  • Understand IS and organizational success or
    failure
  • Understand the future of IS management

5
Information Systems Defined
  • Combinations of hardware, software, and
    telecommunications networks that people build and
    use to collect, create, and distribute useful
    data in organizations

6
Key Elements of Information Systems
7
Data
  • Data raw material, unformatted information
  • Information processed data (meaningful)
  • Knowledge understanding relationships between
    pieces of information
  • Wisdom knowledge accumulated and applied

8
Knowledge as a Business Resource
  • Knowledge Worker
  • A well-educated professional who creates,
    modifies, or synthesizes knowledge in ones
    profession
  • Knowledge Society
  • Also called digital society, new economy
  • Working with brains instead of hands
  • The importance of education
  • Digital divide

9
Technology and Information Systems
  • Computer-Based Information Systems
  • One type of technology
  • Technology any mechanical and/or electrical
    means to supplement, extend, or replace human
    activity
  • Information Technology (IT) machine technology
    controlled by or using information
  • The goal of IS is to provide useful data to users
  • IS can be local or global, organizational or
    enterprise-wide

10
IS Managerial Personnel
  • CIO
  • IS director
  • Account Executive
  • Info Center Manager
  • Development Manager
  • Project Manager
  • Maintenance Manager
  • Systems Manager
  • IS planning Manager
  • Operations Manager
  • Programming Manager
  • Systems Programming Manager
  • Manager of Emerging Technologies
  • Telecommunications Manager
  • Network Manager
  • Database Administrator
  • Auditing or Computer Security Manager
  • Quality Assurance Manager
  • Webmaster

11
Integrating Skills and Knowledge
  • Technology
  • hardware, software, networking
  • Business
  • business, management, social, communications
  • Systems
  • Integration, development methods, critical
    thinking, problem solving

12
Hot Skills in IS Workers
  • Office / E-mail
  • Languages
  • Applications
  • RDBS Administration
  • Development Tools
  • Internetworking
  • Operating Systems
  • LAN Administration
  • Networking

13
IS Within the Firm
  • Traditionally a love/hate relationship
  • Techies vs. mere users (us vs. them)
  • Poor service, lousy attitudes
  • Now progress toward better customer service
  • Better relationships within the company
  • Cooperation, not rivalry

14
The Spread of Technology in Organizations
  • Technology infiltrates business units
  • Dual role for IS workers
  • Work with IS technical group
  • Work with business unit (marketing, finance, etc.)

15
The Spread of Technology in Organizations
  • Benefits of centralized IS function
  • Coordinated planning
  • Consistent management
  • Systems compatibility and connectivity

16
Questions
  • Define and understand the term information
    systems (IS)
  • Explain the technology, people, and
    organizational components of an information
    system.

17
Chapter 2Information Systems for Competitive
Advantage
18
Chapter 2 Objectives
  • Understand the IS in automation, organizational
    learning, and strategic support
  • Understand IS for strategic organizational
    success
  • Understand the need for making an IS business
    case
  • Understand technological innovations to improve
    competitive advantage

19
Why Use Information Systems?
  • Automating doing things faster
  • Organizational learning doing things better
  • Supporting Strategy doing things smarter

20
Automating Doing Things Faster
  • Technology is used to automate a manual process
  • Doing things faster, better, cheaper
  • Greater accuracy and consistency
  • Loan application example
  • Manual processing
  • Technology-supported process
  • Completely automated

21
Organizational Learning Doing Things Better
  • Going beyond automation
  • Involves learning to improve the day-to-day
    activities within the process
  • Looking at patterns and trends
  • Organizational Learning
  • Using acquired knowledge and insights to improve
    organizational behavior
  • Total Quality Management (TQM)
  • Monitoring an organization to improve quality of
    operations, products, and services

22
Supporting Strategy Doing Things Smarter
  • Strategic Planning
  • Create a vision setting the direction
  • Create a standard performance targets
  • Create a strategy reaching the goal

23
Question
  • Now, it should be fairly obvious why an IS
    professional should be able to make a business
    case for a given system. Why, however, is it just
    as important for non-IS professionals? How are
    they involved in this process? What is their role
    in information systems planning?

24
Chapter 3OrganizationalInformation Systems
25
Chapter Objectives
  • Understand characteristics of operational,
    managerial, and executive information systems
  • Understand characteristics of transaction
    processing systems, management information
    systems, and executive information systems
  • Understand characteristics of information systems
    that span organizational boundaries

26
Decision-Making Levels of an Organization
27
Decision-Making Levels of an Organization
  • Executive level (top)
  • Long-term decisions
  • Unstructured decisions
  • Managerial level (middle)
  • Decisions covering weeks and months
  • Semistructured decisions
  • Operational level (bottom)
  • Day-to-day decisions
  • Structured decisions

28
General Types of Information Systems
  • Transaction Processing Systems (TPSs)
  • Transactions
  • Used at Operational level of the organization
  • Goal to automate repetitive information
    processing activities
  • Increase speed
  • Increase accuracy
  • Greater efficiency

29
General Types of Information Systems
  • Data input
  • Manual data entry
  • Semiautomated data entry
  • Fully automated data entry
  • Examples
  • Payroll
  • Sales and ordering
  • Inventory
  • Purchasing, receiving, shipping
  • Accounts payable and receivable

30
General Types of Information Systems
  • Management Information Systems (MISs)
  • Two Types
  • Management of IS in organizations
  • Specific information systems for mid-level
    managers
  • Used at managerial level of the organization

31
General Types of Information Systems
  • Management Information Systems
  • Types of reports
  • Scheduled report
  • Key-indicator report
  • Exception report
  • Drill-down report
  • Ad hoc report

32
General Types of Information Systems
  • Management Information Systems (MISs)
  • Examples
  • Sales forecasting
  • Financial management and forecasting
  • Manufacturing planning and scheduling
  • Inventory management and planning
  • Advertising and product pricing

33
General Types of Information Systems
  • Executive Information Systems (EISs)
  • Used at executive level of the organization
  • Highly aggregated form
  • Data types
  • Soft data news and nonanalytical data
  • Hard data facts and numbers

34
General Types of Information Systems
  • Executive Information Systems (EISs)
  • Examples
  • Executive-level decision making
  • Long-range and strategic planning
  • Monitoring internal and external events
  • Crisis management
  • Staffing and labor relations

35
1.35
36
Information Systems that Span Organizational
Boundaries
37
Information Systems that Span Organizational
Boundaries
  • Decision Support Systems (DSSs)
  • Designed to support organizational decision
    making
  • What-if analysis
  • Example of a DSS tool Microsoft Excel
  • Text and graphs
  • Models for each of the functional areas
  • Accounting, finance, personnel, etc.

38
Information Systems that Span Organizational
Boundaries
  • Expert Systems (ESs)
  • Mimics human expertise by manipulating knowledge
  • Rules (If-then)
  • Inferencing

39
Information Systems that Span Organizational
Boundaries
  • Office Automation Systems (OASs)
  • Examples
  • Communicating and scheduling
  • Document preparation
  • Analyzing data
  • Consolidating information

40
Information Systems that Span Organizational
Boundaries
  • Collaboration Technologies
  • Virtual teams
  • Videoconferencing
  • Groupware
  • Electronic Meeting Systems (EMSs)

41
Information Systems that Span Organizational
Boundaries
  • Functional Area Information Systems
  • Geared toward specific areas in the company
  • Human Resources
  • Benefits
  • Marketing

42
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43
Information Systems that Span Organizational
Boundaries
  • Global Information Systems
  • International IS
  • Transnational IS
  • Multinational IS
  • Global IS

44
Chapter 4Enterprise-WideInformation Systems
45
Chapter Objectives
  • Understand how information technology supports
    business activities
  • Understand enterprise systems and how they
    evolved
  • Understand software applications that are
    internally or externally focused
  • Understand how to implement enterprise systems

46
Enterprise Systems
  • Enterprise systems
  • Also known as enterprise-wide information systems
  • Information systems that allow companies to
    integrate information across operations on a
    company-wide basis

47
Before an entreprise system
48
With an entreprise sytem
49
Types of Enterprise Systems
  • Packaged applications
  • Custom applications
  • Stand-alone applications

50
Types of Enterprise Systems
  • Enterprise Resource Planning
  • Integrated applications
  • ERP systems
  • Baan
  • Oracle
  • PeopleSoft
  • SAP

51
Types of Enterprise Systems
  • ERP Implementation
  • Modules
  • Customizations
  • Best practices
  • Business process reengineering (BPR)

52
Types of Enterprise Systems
  • Customer Relationship Management (CRM)
  • Sales Force Automation (SFA)
  • New opportunities for competitive advantage
  • Examples
  • MGM
  • American Airlines
  • Marriott International

53
CRM system
54
Types of Enterprise Systems
  • Supply Chain Management (SCM)
  • Supply chain the producers of supplies that a
    company uses
  • Supply network
  • What if supply chain does not collaborate?
  • Two objectives of upstream information flow
  • Accelerate product development
  • Reduce costs associated with suppliers

55
Supply chain management
56
The Formula for Enterprise System Success
  • Secure executive sponsorship
  • Get help from outside experts
  • Thoroughly train users
  • Take a multidisciplinary approach to
    implementation

57
Questions
  1. List the different classes of information systems
    described in this chapter. How do they differ
    from each other?
  2. Of the information systems listed in the chapter,
    how many do you have experience with? What
    systems would you like to work with? What types
    of systems do you encounter at the university you
    are attending?
  3. Consider an organization that you are familiar
    with, perhaps the one in which you work or one
    with which you have done business. Describe the
    type of information systems that organization
    uses and whether or not they are useful or
    up-to-date. List specific examples for updating
    or installing information systems that improve
    productivity or efficiency.

58
Chapter 5Information SystemsDevelopment
Acquisition
59
Chapter Objectives
  • Understand the process of IS management
  • Understand the system development life cycle
    (SDLC)
  • Understand alternative approaches to system
    development
  • Understand in-house system development
  • Understand external acquisition, outsourcing, and
    end-user development

60
The Need for Structured Systems Development
  • Systems analysis and design the process of
    designing, building, and maintaining information
    systems
  • Systems analyst
  • Blending technical and managerial expertise

61
The Need for Structured Systems Development
  • Evolution of IS development
  • From art to a discipline
  • Standardized development methods
  • Software engineering

62
The Need for Structured Systems Development
  • Options for Obtaining Information Systems
  • Build your own
  • Buy a prepackaged system
  • Outsource development to a 3rd party
  • End user development

63
The Need for Structured Systems Development
  • Information Systems Development in Action
  • Breaking large complex problems into manageable
    pieces
  • Decomposing large, complex problems

64
The Need for Structured Systems Development
  • System Construction Process
  • Identify a large IT problem to solve
  • Break the large problem into several smaller,
    more manageable pieces
  • Translate each piece (small problem) into
    computer programs
  • Piece together each program into an overall
    comprehensive IS that solves the problem

65
The Need for Structured Systems Development
  • The Role of Users in the Systems Development
    Process
  • Knowledgeable of needs
  • Effective partnership

66
Information Systems Analysis and Design
  • Systems Analyst performs analysis and design
    based upon
  • Understanding of organizations objectives,
    structure and processes
  • Knowledge of how to exploit information
    technology for advantage

67
Systems Analysis and Design Core Concepts
  • Major goal to improve organizational systems by
    developing or acquiring software and training
    employees in its use
  • Application software, or a system, supports
    organizational functions or processes

68
Systems Analysis and Design Core Concepts
  • System Turns data into information and includes
  • Hardware and system software
  • Documentation and training materials
  • Job roles associated with the system
  • Controls to prevent theft or fraud
  • The people who use the software to perform their
    jobs

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Software Engineering Process
  • A process used to create an information system
  • Consists of
  • Methodologies
  • A sequence of step-by-step approaches that help
    develop the information system
  • Techniques
  • Processes that the analyst follows to ensure
    thorough, complete and comprehensive analysis and
    design
  • Tools
  • Computer programs that aid in applying techniques

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System
  • A system is an interrelated set of business
    procedures used within one business unit working
    together for a purpose
  • A system has nine characteristics
  • A system exists within an environment
  • A boundary separates a system from its environment

73
Characteristics of a System
  • Components
  • Interrelated Components
  • Boundary
  • Purpose
  • Environment
  • Interfaces
  • Constraints
  • Input
  • Output

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Important System Concepts
  • Decomposition
  • The process of breaking down a system into
    smaller components
  • Allows the systems analyst to
  • Break a system into small, manageable subsystems
  • Focus on one area at a time
  • Concentrate on component pertinent to one group
    of users
  • Build different components at independent times

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Important System Concepts
  • Modularity
  • Process of dividing a system into modules of a
    relatively uniform size
  • Modules simplify system design
  • Coupling
  • Subsystems that are dependent upon each other are
    coupled
  • Cohesion
  • Extent to which a subsystem performs a single
    function

78
A Modern Approach to Systems Analysis and Design
  • Systems Integration
  • Allows hardware and software from different
    vendors to work together
  • Enables procedural language systems to work with
    visual programming systems
  • Visual programming environment uses client/server
    model

79
Data and Processes
  • Three key components of an information system
  • Data
  • Data Flows
  • Processing Logic
  • Data vs. Information
  • Data
  • Raw facts
  • Information
  • Derived from data
  • Organized in a manner that humans can
  • understand

80
Data and Processes
  • Data
  • Understanding the source and use of data is key
    to good system design
  • Various techniques are used to describe data and
    the relationship amongst data
  • Data Flows
  • Groups of data that move and flow through the
    system
  • Include description of sources and destination
    for each data flow
  • Processing Logic
  • Describe steps that transform data and events
    that trigger the steps

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Approaches to Systems Development
  • Process-Oriented Approach
  • Focus is on flow, use and transformation of data
    in an information system
  • Involves creating graphical representations such
    as data flow diagrams and charts
  • Data are tracked from sources, through
    intermediate steps and to final destinations
  • Natural structure of data is not specified
  • Disadvantage data files are tied to specific
    applications

83
Approaches to Systems Development (2)
  • Data-Oriented Approach
  • Depicts ideal organization of data, independent
    of where and how data are used
  • Data model describes kinds of data and business
    relationships among the data
  • Business rules depict how organization captures
    and processes the data

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Databases and Application Independence
  • Database
  • Shared collection of logically related data
  • Organized to facilitate capture, storage and
    retrieval by multiple users
  • Centrally managed
  • Designed around subjects
  • Customers
  • Suppliers
  • Application Independence
  • Separation of data and definition of data from
    applications

86
Role of the Systems Analyst
  • Study problems and needs of an organization
  • Determine best approach to improving organization
    through use of
  • People
  • Methods
  • Information technology
  • Help system users and managers define their
    requirements for new or enhanced systems

87
Role of the Systems Analyst
  • Assess options for system implementation
  • In-house development
  • Outsourced development
  • Outsourced development and operation
  • Commercial application
  • For in-house projects, work on a team of analysts
    and developers

88
Skills of a Successful Systems Analyst
  • Analytical
  • Understanding of organizations
  • Problem-solving skills
  • System thinking
  • Ability to see organizations and information
    systems as systems
  • Technical
  • Understanding of potential and limitations of
    technology
  • Managerial
  • Ability to manage projects, resources, risk and
    change
  • Interpersonal
  • Effective written and oral communication skills

89
Systems Development Life Cycle
  • System Development Methodology
  • Standard process followed in an organization
  • Consists of
  • Analysis
  • Design
  • Implementation
  • Maintenance

90
Systems Development Life Cycle
  • Series of steps used to manage the phases of
    development for an information system
  • Consists of four phases
  • Planning and Selection
  • Analysis
  • Design
  • Implementation and Operation

91
Systems Development Life Cycle
  • Phases are not necessarily sequential
  • Each phase has a specific outcome and deliverable
  • Individual companies use customized life cycle

92
Phases of the Systems Development Life Cycle
  • Systems Planning and Selection
  • Two Main Activities
  • Identification of need
  • Investigation and determination of scope
  • Systems Analysis
  • Study of current procedures and information
    systems
  • Determine requirements
  • Generate alternative designs
  • Compare alternatives
  • Recommend best alternative

93
Systems Development Life Cycle
  • System Design
  • Logical Design
  • Concentrates on business aspects of the system
  • Physical Design
  • Technical specifications
  • Implementation and Operation
  • Implementation
  • Hardware and software installation
  • Programming
  • User Training
  • Documentation
  • Operation
  • System changed to reflect changing conditions
  • System obsolescence

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Alternative approaches
  • Prototyping
  • Building a scaled-down working version of the
    system
  • Advantages
  • Users are involved in design
  • Captures requirements in concrete form
  • Rapid Application Development (RAD)
  • Utilizes prototyping to delay producing system
    design until after user requirements are clear
  • Joint Application Design (JAD)
  • Users, Managers and Analysts work together for
    several days
  • System requirements are reviewed
  • Structured meetings

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Summary
  • Information systems analysis and design
  • Process of developing and maintaining an
    information system
  • Modern approach to systems analysis
  • Process-Oriented
  • Data-Oriented

98
Summary
  • Systems Development Life Cycle (SDLC)
  • Systems Planning and Selection
  • Systems Analysis
  • Systems Design
  • Systems Implementation
  • Alternatives to Systems Development Life Cycle
  • Prototyping
  • Rapid Application Development (RAD)
  • Joint Application Design (JAD)

99
Questions
  • In what way are organizations systems?
  • List and explain the different phases in the
    systems development life cycle.
  • Why is it important to use systems analysis and
    design methodologies when building a system? Why
    not just build the system in whatever way seems
    to be quick and easy? What value is provided
    by using an engineering approach?
  • Explain the traditional application-based
    approach to systems development. How is this
    different from the data-based approach?
  • What is prototyping?
  • What is JAD? What is Participatory Design?

100
Chapter 6 Managing the Information Systems
Project
101
Learning Objectives
  • Discuss skills required to be an effective
    project manager
  • Describe skills and activities of a project
    manager during project initiation, planning,
    execution and closedown
  • Explain Gantt Charts and Network Diagrams
  • Review commercial project management software
    packages

102
Case of Pine Valley Furniture
  • Manufacturing Company
  • Product Wood Furniture
  • Market U.S.
  • Organized into functional areas
  • Manufacturing
  • Sales
  • Three independent computer systems were converted
    to a database in 1990s

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Managing the Information Systems Project
  • Focus of project management
  • To ensure that information system projects meet
    customer expectations
  • Delivered in a timely manner
  • Meet constraints and requirements

105
Managing the Information Systems Project
  • Project Manager
  • Systems Analyst responsible for
  • Project initiation
  • Planning
  • Execution
  • Closing down
  • Requires diverse set of skills
  • Management
  • Leadership
  • Technical
  • Conflict management
  • Customer relations

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Project Management Process
  • Project
  • Planned undertaking of related activities to
    reach an objective that has a beginning and an
    end
  • Four Phases
  • Initiation
  • Planning
  • Execution
  • Closing down

108
Initiating the Project
  1. Establish project initiation team
  2. Establish relationship with customer
  3. Establish project initiation plan
  4. Establish management procedures
  5. Establish project management environment and
    workbook

109
Planning the Project
  • Describe project scope, alternatives and
    feasibility
  • Scope and Feasibility
  • Understand the project
  • What problem is addressed
  • What results are to be achieved
  • Measures of success
  • Completion criteria

110
Planning the Project
  • Divide the project into manageable tasks
  • Work breakdown structure
  • Gantt chart
  • Estimate resources and create a resource plan
  • Develop a preliminary schedule
  • Utilize Gantt Charts and Network Diagrams
  • Develop a communication plan
  • Outline communication processes among customers,
    team members and management
  • Types of reports
  • Frequency of reports

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Planning the Project
  • Determine project standards and procedures
  • Specify how deliverables are tested and produced
  • Identify and assess risk
  • Identify sources of risk
  • Estimate consequences of risk
  • Create a preliminary budget
  • Develop a statement of work
  • Describe what the project will deliver
  • Set a baseline project plan
  • Estimate of projects tasks and resources

113
Executing the Project
  • Execute baseline project plan
  • Acquire and assign resources
  • Train new team members
  • Keep project on schedule
  • Monitor project progress
  • Adjust resources, budget and/or activities
  • Manage changes to baseline project plan
  • Slipped completion dates
  • Changes in personnel
  • New activities
  • Maintain project workbook
  • Communicate project status

114
Closing Down the Project
  • Termination
  • Types of termination
  • Natural
  • Requirements have been met
  • Unnatural
  • Project stopped
  • Documentation
  • Personnel Appraisal
  • Conduct post-project reviews
  • Determine strengths and weaknesses of
  • Project deliverables
  • Project management process
  • Development process
  • Close customer contract

115
Representing and Scheduling Project Plans
  • Gantt Charts
  • Useful for depicting simple projects or parts of
    large projects
  • Show start and completion dates for individual
    tasks
  • Network Diagrams
  • Show order of activities

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118
Summary
  • Skills of an effective project manager
  • Activities of project manager
  • Initiation
  • Planning
  • Execution
  • Closedown
  • Gantt Charts and Network Diagrams
  • Commercial PM Software

119
Questions
  1. List and describe the common skills and
    activities of a project manager. Which skill do
    you think is most important? Why?
  2. Describe the activities performed by the project
    manager during project initiation.
  3. Describe the activities performed by the project
    manager during project planning.
  4. Describe the activities performed by the project
    manager during project execution.

120
Chapter 7 Systems Planning
121
Learning Objectives
  • Discuss the content of and need for a Statement
    of Work and Baseline Project Plan
  • Describe a structured walkthrough

122
First documents
  • Baseline Project Plan (BPP) internal document
  • Scope
  • Benefits
  • Costs
  • Risks
  • Resources
  • Statement of Work (SOW) Outlines objectives and
    constraints of the project to the customer
  • Describes deliverables
  • Outlines work needed to be performed

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Building the Baseline Project Plan
  • Objectives
  • Assures that customer and development group have
    a complete understanding of the proposed system
    and requirements
  • Provides sponsoring organization with a clear
    idea of scope, benefits and duration of project
  • Four Sections
  • Introduction
  • System Description
  • Feasibility Assessment
  • Management Issues

125
Building the Baseline Project Plan
  • Introduction
  • Brief overview
  • Recommended course of action
  • Project scope defined
  • Units affected
  • Interaction with other systems
  • Range of system capabilities

126
Building the Baseline Project Plan
  • System Description
  • Outline of possible alternative solutions
  • Narrative format
  • Feasibility Assessment
  • Project costs and benefits
  • Technical difficulties
  • High-level project schedule

127
Building the Baseline Project Plan
  • Management Issues
  • Outlines concerns that management may have about
    the project
  • Team composition
  • Communication plan
  • Project standards and procedures

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Reviewing the Baseline Project Plan
  • Objectives
  • Assure conformity to organizational standards
  • All parties agree to continue with project

130
Reviewing the Baseline Project Plan
  • Walkthrough
  • Peer group review
  • Participants
  • Coordinator
  • Presenter
  • User
  • Secretary
  • Standards Bearer
  • Maintenance Oracle
  • Activities
  • Walkthrough review form
  • Individuals polled
  • Walkthrough action list
  • Advantages
  • Assures that review occurs during project

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Summary
  • Baseline Project Plan (BPP)
  • Created during project initiation and planning
  • Contains
  • Introduction
  • High-Level description of system
  • Outline of feasibility
  • Overview of Management Issues
  • Statement of Work (SOW)
  • Describes what project will deliver
  • Lists all work to be performed

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Questions
  • What is contained in a Baseline Project Plan?
    Are the content and format of all baseline plans
    the same? Why or why not?
  • Describe the structured walkthrough process.
    What roles need to be performed during a
    walkthrough?

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Chapter 8 Determining System Requirements
136
Learning Objectives
  • Describe options for designing and conducting
    interviews
  • Discuss planning an interview
  • Discuss using questionnaires to determine system
    requirements
  • Explain advantages and disadvantages of observing
    workers and analyzing business documents to
    determine requirements

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Learning Objectives
  • Learn about Joint Application Design (JAD) and
    Prototyping
  • Discuss appropriate methods to elicit system
    requests
  • Examine requirements determination for Internet
    applications

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Activities in Requirement Gathering
2.0 Use most appropriate investigation techniques
4.0 Document the requirements
1.0 Identify the right Stakeholders Artefacts
3.0 Determine duration
0.0 Outline information to be sought
Objective determine the functions information
that must be provided by the information system
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Performing Requirements Determination
  • Gather information on what the system should do
    from many sources
  • Users
  • Reports
  • Forms
  • Procedures

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Performing Requirements Determination
  • Characteristics for gathering requirements
  • Impertinence
  • Question everything
  • Impartiality
  • Find the best organizational solution
  • Relaxation of constraints
  • Attention to detail
  • Reframing
  • View the organization in new ways

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Deliverables and Outcomes
  • Types of deliverables
  • Information collected from users
  • Existing documents and files
  • Computer-based information
  • Understanding of organizational components
  • Business objective
  • Information needs
  • Rules of data processing
  • Key events

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Deliverables and Outcomes
143
Traditional Methods for Determining Requirements
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Traditional Methods for Determining Requirements
  • Interviewing and Listening
  • Gather facts, opinions and speculations
  • Observe body language and emotions
  • Guidelines
  • Plan
  • Checklist
  • Appointment
  • Be neutral
  • Listen
  • Seek a diverse view
  • Interview Questions
  • Open-Ended
  • No prespecified answers
  • Close-Ended
  • Respondent is asked to choose from a set of
    specified responses

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Traditional Methods for Determining Requirements
  • Administering Questionnaires
  • More cost-effective than interviews
  • Choosing respondents
  • Should be representative of all users
  • Types of samples
  • Convenient
  • Random sample
  • Purposeful sample
  • Stratified sample
  • Design
  • Mostly closed-ended questions
  • Can be administered over the phone, in person or
    over the Internet or company intranet

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Traditional Methods for Determining Requirements
  • Questionnaires Vs. Interviews
  • Interviews cost more but yield more information
  • Questionnaires are more cost-effective

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Traditional Methods for Determining Requirements
  • Directly Observing Users
  • Serves as a good method to supplement interviews
  • Often difficult to obtain unbiased data
  • People often work differently when being observed

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Analyzing Procedures and Other Documents
  • Types of information to be discovered
  • Problems with existing system
  • Opportunity to meet new need
  • Organizational direction
  • Names of key individuals
  • Values of organization
  • Special information processing circumstances
  • Rules for processing data

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Modern Methods for Determining Requirements
  • Joint Application Design (JAD)
  • Brings together key users, managers and systems
    analysts
  • Purpose collect system requirements
    simultaneously from key people
  • Conducted off-site
  • Prototyping
  • Repetitive process
  • Rudimentary version of system is built
  • Replaces or augments SDLC
  • Goal to develop concrete specifications for
    ultimate system

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Joint Application Design (JAD)
  • Participants
  • Session Leader
  • Users
  • Managers
  • Sponsor
  • Systems Analysts
  • Scribe
  • IS Staff
  • End Result
  • Documentation detailing existing system
  • Features of proposed system

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Prototyping
  • Quickly converts requirements to working version
    of system
  • Once the user sees requirements converted to
    system, will ask for modifications or will
    generate additional requests
  • Most useful when
  • User requests are not clear
  • Few users are involved in the system
  • Designs are complex and require concrete form
  • History of communication problems between
    analysts and users
  • Tools are readily available to build prototype

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Prototyping
  • Drawbacks
  • Tendency to avoid formal documentation
  • Difficult to adapt to more general user audience
  • Sharing data with other systems is often not
    considered
  • Systems Development Life Cycle (SDLC) checks are
    often bypassed

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Summary
  • Interviews
  • Open-ended and close-ended questions
  • Preparation is key
  • Questionnaires
  • Must be carefully designed
  • Can contain close-ended as well as open-ended
    questions

160
Summary
  • Other means of gathering requirements
  • Observing workers
  • Analyzing business documents
  • Joint Application Design (JAD)
  • Prototyping

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Questions (1)
  1. Describe systems analysis and the major
    activities that occur during this phase of the
    systems development life cycle.
  2. What are some useful character traits for an
    analyst involved in requirements determination?
  3. Describe four traditional techniques for
    collecting information during analysis. When
    might one be better than another?
  4. What are the general guidelines for conducting
    interviews?
  5. What are the general guidelines for designing
    questionnaires?
  6. Compare collecting information by interview and
    by questionnaire. Describe a hypothetical
    situation in which each of these methods would be
    an effective way to collect information system
    requirements.

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Questions (2)
  1. What are the general guidelines for collecting
    data through observing workers?
  2. What are the general guidelines for collecting
    data through analyzing documents?
  3. Describe how prototyping can be used during
    requirements determination. How is it better or
    worse than traditional methods?

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Chapter 9 Structuring System RequirementsProces
s Modeling
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Learning Objectives
  • Understand the logical modeling of processes
    through studying data flow diagrams
  • How to draw data flow diagrams using rules and
    guidelines
  • How to decompose data flow diagrams into
    lower-level diagrams
  • Balancing of data flow diagrams

165
Learning Objectives
  • Discuss the use of data flow diagrams as analysis
    tools
  • Discuss process modeling for Internet
    Applications

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Process Modeling
  • Graphically represent the processes that capture,
    manipulate, store and distribute data between a
    system and its environment and among system
    components
  • Data flow diagrams (DFD)
  • Graphically illustrate movement of data between
    external entities and the processes and data
    stores within a system

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Process Modeling
  • Modeling a systems process
  • Utilize information gathered during requirements
    determination
  • Structure of the data is also modeled in addition
    to the processes
  • Deliverables and Outcomes
  • Set of coherent, interrelated data flow diagrams

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Process Modeling
  • Deliverables and outcomes (continued)
  • Context data flow diagram (DFD)
  • Scope of system
  • DFDs of current system
  • Enables analysts to understand current system
  • DFDs of new logical system
  • Technology independent
  • Show data flows, structure and functional
    requirements of new system

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Data Flow Diagramming Mechanics
  • Data Flow
  • Depicts data that are in motion and moving as a
    unit from one place to another in the system
  • Drawn as an arrow
  • Select a meaningful name to represent the data

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Data Flow Diagramming Mechanics
  • Data Store
  • Depicts data at rest
  • May represent data in
  • File folder
  • Computer-based file
  • Notebook
  • Drawn as a rectangle with the right hand vertical
    line missing
  • Label includes name of the store as well as the
    number

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Data Flow Diagramming Mechanics
  • Process
  • Depicts work or action performed on data so that
    they are transformed, stored or distributed
  • Drawn as a rectangle with rounded corners
  • Number of process as well as name are recorded

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Data Flow Diagramming Mechanics
  • Source/Sink
  • Depicts the origin and/or destination of the data
  • Sometimes referred to as an external entity
  • Drawn as a square symbol
  • Name states what the external agent is
  • Because they are external, many characteristics
    are not of interest to us

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Data Flow Diagramming Definitions
  • Context Diagram
  • A data flow diagram (DFD) of the scope of an
    organizational system that shows the system
    boundaries, external entities that interact with
    the system and the major information flows
    between the entities and the system
  • Level-O Diagram
  • A data flow diagrams (DFD) that represents a
    systems major processes, data flows and data
    stores at a higher level

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Developing DFDs An Example
  • Hoosier Burgers automated food ordering system
  • Context Diagram contains no data stores

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Developing DFDs An Example
  • Next step is to expand the context diagram to
    show the breakdown of processes

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Data Flow Diagramming Rules
  • Basic rules that apply to all DFDs
  • Inputs to a process are always different than
    outputs
  • Objects always have a unique name
  • In order to keep the diagram uncluttered, you can
    repeat data stores and data flows on a diagram

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Data Flow Diagramming Rules
  • Process
  • No process can have only outputs (a miracle)
  • No process can have only inputs (black hole)
  • A process has a verb phrase label
  • Data Store
  • Data cannot be moved from one store to another
  • Data cannot move from an outside source to a data
    store
  • Data cannot move directly from a data store to a
    data sink
  • Data store has a noun phrase label

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Data Flow Diagramming Rules
  • Source/Sink
  • Data cannot move directly from a source to a sink
  • A source/sink has a noun phrase label
  • Data Flow
  • A data flow has only one direction of flow
    between symbols
  • A fork means that exactly the same data go from a
    common location to two or more processes, data
    stores or sources/sinks

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Data Flow Diagramming Rules
  • Data Flow (Continued)
  • A join means that exactly the same data come from
    any two or more different processes, data stores
    or sources/sinks to a common location
  • A data flow cannot go directly back to the same
    process it leaves
  • A data flow to a data store means update
  • A data flow from a data store means retrieve or
    use
  • A data flow has a noun phrase label

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Decomposition of DFDs
  • Functional decomposition
  • Act of going from one single system to many
    component processes
  • Repetitive procedure
  • Lowest level is called a primitive DFD
  • Level-N Diagrams
  • A DFD that is the result of n nested
    decompositions of a series of subprocesses from a
    process on a level-0 diagram

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Balancing DFDs
  • When decomposing a DFD, you must conserve inputs
    to and outputs from a process at the next level
    of decomposition
  • This is called balancing
  • Example Hoosier Burgers
  • In Figure 5-4, notice that there is one input to
    the system, the customer order
  • Three outputs
  • Customer receipt
  • Food order
  • Management reports

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Balancing DFDs
  • Example (Continued)
  • Notice Figure 5-5. We have the same inputs and
    outputs
  • No new inputs or outputs have been introduced
  • We can say that the context diagram and level-0
    DFD are balanced

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Balancing DFDsAn Unbalanced Example
  • In context diagram, we have one input to the
    system, A and one output, B
  • Level-0 diagram has one additional data flow, C
  • These DFDs are not balanced

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Balancing DFDs
  • We can split a data flow into separate data flows
    on a lower-level diagram

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Balancing DFDsFour Additional Advanced Rules
191
Guidelines for Drawing DFDs
  • Completeness
  • DFD must include all components necessary for
    system
  • Each component must be fully described in the
    project dictionary or CASE repository
  • Consistency
  • The extent to which information contained on one
    level of a set of nested DFDs is also included on
    other levels

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Guidelines for Drawing DFDs
  • Timing
  • Time is not represented well on DFDs
  • Best to draw DFDs as if the system has never
    started and will never stop
  • Iterative Development
  • Analyst should expect to redraw diagram several
    times before reaching the closest approximation
    to the system being modeled
  • Primitive DFDs
  • Lowest logical level of decomposition
  • Decision has to be made when to stop decomposition

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Using DFDs as Analysis Tools
  • Gap Analysis
  • The process of discovering discrepancies between
    two or more sets of data flow diagrams or
    discrepancies within a single DFD
  • Inefficiencies in a system can often be
    identified through DFDs

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Using DFDs in Business Process Reengineering
  • Example IBM Credit
  • Credit approval process required six days before
    Business Process Reengineering (see Fig 5-12)

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Using DFDs in Business Process Reengineering
  • After Business Reprocess Engineering, IBM was
    able to process 100 times the number of
    transactions in the same amount of time

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Summary
  • Data flow diagrams (DFD)
  • Symbols
  • Rules for creating
  • Decomposition
  • Balancing
  • DFDs for Analysis
  • DFDs for Business Process Reengineering (BPR)

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Questions
  1. What is a data flow diagram? Why do systems
    analysts use data flow diagrams?
  2. What is decomposition? What is balancing? How
    can you determine if DFDs are not balanced?
  3. Explain the convention for naming different
    levels of data flow diagrams.
  4. How can data flow diagrams be used as analysis
    tools?

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Chapter 10Structuring System RequirementsConcep
tual Data Modeling
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Learning Objectives
  • Define key data-modeling terms
  • Conceptual data model
  • Entity-Relationship (E-R) diagram
  • Entity type
  • Entity instance
  • Attribute
  • Candidate key
  • Multivalued attributes
  • Relationship
  • Degree
  • Cardinality
  • Associative entity

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Learning Objectives
  • Ask the right kinds of questions to determine
    data requirements for an IS
  • Learn to draw entity-relationship diagrams (ERD)
  • Review the role of conceptual data modeling in
    overall design and analysis of an information
    system
  • Discuss relationships and associative entities
  • Discuss relationship between data modeling and
    process modeling

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Conceptual Data Modeling
  • Representation of organizational data
  • Purpose is to show rules about the meaning and
    interrelationships among data
  • Entity-Relationship (E-R) diagrams are commonly
    used to show how data are organized
  • Main goal of conceptual data modeling is to
    create accurate E-R diagrams
  • Methods such as interviewing, questionnaires and
    JAD are used to collect information
  • Consistency must be maintained between process
    flow, decision logic and data modeling
    descriptions

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Process of Conceptual Data Modeling
  • First step is to develop a data model for the
    system being replaced
  • Next, a new conceptual data model is built that
    includes all the requirements of the new system
  • In the design stage, the conceptual data model is
    translated into a physical design
  • Project repository links all design and data
    modeling steps performed during SDLC

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Deliverables and Outcomes
  • Primary deliverable is the entity-relationship
    diagram
  • There may be as many as 4 E-R diagrams produced
    and analyzed during conceptual data modeling
  • Covers just data needed in the projects
    application
  • E-R diagram for system being replaced
  • An E-R diagram for the whole database from which
    the new applications data are extracted
  • An E-R diagram for the whole database from which
    data for the application system being replaced
    are drawn

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Deliverables and Outcomes
  • Second deliverable is a set of entries about data
    objects to be stored in repository or project
    dictionary
  • Repository links data, process and logic models
    of an information system
  • Data elements that are included in the DFD must
    appear in the data model and conversely
  • Each data store in a process model must relate to
    business objects represented in the data model
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