Chapter 3 Study Tool

Report
Systems Analysis & Design
5th Edition
Chapter 3
Requirements Modeling
Phase Description
● Systems analysis is the second of five
phases in the systems development life
cycle (SDLC)
● Uses requirements modeling and
enterprise modeling to represent the
new system
● Before proceeding to the next phase,
systems design, you will consider
system development strategies
2
Chapter Objectives
● Describe systems analysis phase
activities and the end product of the
systems analysis phase
● Understand joint application development
(JAD) and rapid application development
(RAD)
● Explain how systems analysts use a
functional decomposition diagram (FDD)
● Describe the Unified Modeling Language
(UML) and explain use case diagrams and
sequence diagrams
3
Chapter Objectives
● List and describe system requirements,
including outputs, inputs, processes,
performance, and controls
● Explain the importance of scalability in
system design
● Use fact-finding techniques, including
interviews, documentation review,
observation, questionnaires, sampling,
and research
4
Chapter Objectives
● Define total cost of ownership (TCO)
and explain the concept
● Conduct a successful interview
● Develop effective documentation
methods to use during systems
development
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Introduction
● This chapter describes requirements
modeling techniques and team-based
methods that systems analysts use to
visualize and document new systems
● The chapter then discusses system
requirements and fact-finding
techniques, which include interviewing,
documentation review, observation,
surveys and questionnaires, sampling,
and research
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Systems Analysis Phase Overview
● Uses models and
other
documentation tools
to visualize and
describe the
proposed system
● The deliverable is a
system
requirements
document
Figure 3-2
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Systems Analysis Phase Overview
● Systems Analysis Skills
– Analytical skills
– Interpersonal skills
● Team-Oriented Methods and Techniques
– Joint application development (JAD)
– Rapid application development (RAD)
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Joint Application Development
● User Involvement
– Users have a vital stake in an
information system and they should
participate fully
– Successful systems must be useroriented and users need to be involved
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Joint Application Development
● JAD Participants and Roles
Figure 3-4
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Joint Application Development
Figure 3-5
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Joint Application Development
● JAD Advantages and Disadvantages
– More expensive and can be cumbersome
– Allows key users to participate effectively
– When properly used, JAD can result in a
more accurate statement of system
requirements, a better understanding of
common goals, and a stronger
commitment to the success of the new
system.
12
Rapid Application Development
● Is a team-based technique that speeds up
information systems development and
produces a functioning information
system
● Relies heavily on prototyping and user
involvement
● Project team uses CASE tools to build the
prototypes and create a continuous
stream of documentation
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Rapid Application Development
● RAD Phases and Activities
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Figure 3-7
Rapid Application Development
● RAD Objectives
– To cut development time and expense
by involving the users in every phase of
systems development
– Successful RAD team must have IT
resources, skills, and management
support
– Helps a development team design a
system that requires a highly interactive
or complex user interface
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Rapid Application Development
● RAD Advantages and Disadvantages
– Systems can be developed more quickly
with significant cost savings
– RAD stresses the mechanics of the
system itself and does not emphasize
the company’s strategic business needs
– Might allow less time to develop quality,
consistency, and design standards
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Modeling Tools and Techniques
● CASE Tools
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Figure 3-8
Modeling Tools and Techniques
● Functional Decomposition Diagrams
– A top-down representation of business
functions and processes
– Also called structure charts
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Modeling Tools and Techniques
● Functional Decomposition Diagrams
Figure 3-9
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Modeling Tools and Techniques
● Unified Modeling Language
– A widely used method of visualizing and
documenting software systems design
– provides various graphical tools and
techniques, such as use case diagrams
and sequence diagrams
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Modeling Tools and Techniques
● Unified Modeling Language
Figure 3-10
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Modeling Tools and Techniques
● Unified Modeling Language
Figure 3-11
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Modeling Tools and Techniques
● Unified Modeling Language
Sequence Diagram
Figure 3-13
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System Requirements Checklist
● System requirement
● Five general categories
– Outputs
– Inputs
– Processes
– Performance
– Controls
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Future Growth, Costs, and Benefits
● Scalability
– A scalable system offers a better return
on the initial investment
– To evaluate, you need information about
projected future volume for all outputs,
inputs, and processes
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Future Growth, Costs, and Benefits
● Total Cost of Ownership
– In addition to direct costs, systems
developers must identify and document
indirect expenses that contribute to the
total cost of ownership (TCO)
– Microsoft has developed a method for
measuring total costs and benefits,
called Rapid Economic Justification
(REJ)
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Fact-Finding
● Overview
– Although software can help you to
gather and analyze facts, no program
actually performs fact-finding for you
– The first step is to identify the
information you need
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Fact-Finding
● Who, What, Where, When, How, and
Why?
Figure 3-15
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Fact-Finding
● The Zachman Framework
– A model that asks the traditional factfinding questions in a systems
development context
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Fact-Finding
Figure 3-16
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Interviews
● Systems analysts spend a great deal of
time talking with people
● Much of that time is spent conducting
interviews
● Consists of 7 steps
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Interview
● Step 1: Determine the People to
Interview
– Informal structures
● Step 2: Establish Objectives
– Determine the general areas to be
discussed
– List the facts you want to gather
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Interviews
● Step 3: Develop Interview Questions
– Creating a standard list of interview
questions helps to keep you on track
and avoid unnecessary tangents
– Avoid leading questions
– Open-ended questions
– Closed-ended questions
– Range-of-response questions
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Interviews
● Step 4: Prepare for the Interview
– Careful preparation is essential because
an important meeting and not just a
casual chat
– Limit the interview to no more than one
hour
– Send a list of topics
– Ask the interviewee to have samples
available
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Interviews
Figure 3-18
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Interviews
Figure 3-19
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Interviews
● Step 5: Conduct the Interview
– Develop a specific plan for the meeting
– Begin with good introduction
– Use engaged listening
– Allow the person enough time to think
about the question
– Summarize main points
– After interview, summarize the session
and seek a confirmation
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Interviews
● Step 6: Document the Interview
– During the interview, note taking should
be kept to a minimum
– After the interview, record the
information quickly
– After the interview, send memo
expressing appreciation, including the
main points discussed so the
interviewee has a written summary and
can offer additions or corrections
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Interviews
● Step 7: Evaluate the Interview
– In addition to recording the facts
obtained in an interview, try to identify
any possible biases
● Unsuccessful Interviews
– No matter how well you prepare for
interviews, some are not successful
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Other Fact-Finding Techniques
● Document Review
● Observation
– Seeing the system in action gives you
additional perspective and a better
understanding of the system procedures
– Plan you observations in advance
– Hawthorne Effect
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Other Fact-Finding Techniques
● Questionnaires and Surveys
– Keep the questionnaire brief and userfriendly
– Provide clear instructions that will
answer all anticipated questions
– Arrange the questions in a logical order,
going from simple to more complex
topics
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Other Fact-Finding Techniques
● Questionnaires and Surveys
– Phrase questions to avoid
misunderstandings; use simple terms
and wording
– Try not to lead the response or use
questions that give clues to expected
answers
– Limit the use of open-ended questions
that are difficult to tabulate
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Other Fact-Finding Techniques
● Questionnaires and Surveys
– Limit the use of questions that can raise
concerns about job security or other
negative issues
– Include a section at the end of the
questionnaire for general comments
– Test the questionnaire whenever
possible on a small test group before
finalizing it and distributing to a large
group
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Other Fact-Finding Techniques
● Sampling
– Systematic sample
– Stratified sample
– Random sample
– Main objective of a sample is to ensure
that it represents the overall population
accurately
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Other Fact-Finding Techniques
● Research
– Newsgroups
– Site visit
Figure 3-23
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Other Fact-Finding Techniques
● Interviews versus Questionnaires
– When you seek input from a large group
questionnaire is a very useful tool
– If you require detailed information from
only a few people, then you probably
should interview each person
– Interview is more familiar and personal
– Questionnaire gives many people the
opportunity to provide input and
suggestions
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Documentation
● The Need for Recording the Facts
– Record information as soon as you
obtain it
– Use the simplest recording method
– Record your findings in such a way that
they can be understood by someone
else
– Organize your documentation
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Documentation
● Software Tools
– CASE tools
– Word
processing
– Spreadsheets
– Databases
Figure 3-24
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Documentation
● Software Tools
– Presentation graphics
– Personal information managers
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Preview of Enterprise Modeling
● At the conclusion of requirements
modeling, systems developers should
have clear understanding of business
processes and system requirements
● The next step is to model the logical
design of the system
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Chapter Summary
● The systems analysis phase includes
three activities
● The main objective is to understand the
proposed project and build a solid
foundation for the systems design phase
● The fact-finding process includes
interviewing, document review,
observation, questionnaires, sampling,
and research.
51
Chapter Summary
● Systems analysts should carefully record
and document factual information as it is
collected, and various software tools can
help an analyst visualize and describe an
information system
● Chapter 3 Complete
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