Modern Systems Analysis and Design Ch6

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					Modern Systems Analysis
      and Design

        Chapter 6
   Determining System
      Requirements
System Requirements Determination




6-2
           What is a Requirement?
A requirement is a statement of what the
system must do or what characteristics it
needs to have.
Examples
     System must allow registered users to view their
      own order history for the past 3 years (process)
     Only direct managers can see personnel records of
      staff (security)
     Any user-system interaction should not exceed 2
      seconds (performance)


6-3
       Deliverables of Requirements
               Determination
 From interviews and observations
     Interview transcripts, observation notes, meeting
      minutes
 From existing written documents
     Mission and strategy statements, business forms,
      procedure manuals, job descriptions, training
      manuals, system documentation, flowcharts
 From computerized sources
     JAD session results, CASE repositories, system
      prototype displays and reports
6-4
     Traditional Requirements
       Determination Methods
Interviewing individuals
Interviewing groups
Observing workers
Studying business documents



6-5
            What is Interviewing?
Dialogue with user or manager to obtain their
requirements

Two forms:
     Open-ended:
      conversational, questions with no specific answers
      in mind
     Closed-ended:
      structured, questions with limited range of possible
      answers


6-6
Guidelines for Effective Interviewing
Plan the interview.
     Prepare interviewee: appointment, priming
      questions.
     Prepare agenda, checklist, questions.
Listen carefully and take notes (tape record if
permitted).
Review notes within 48 hours.
Be neutral.
Seek diverse views.



6-7
      Interview
      Guide is a
      document for
      developing,
      planning and
      conducting an
      interview.
      Each question
      in an interview
      guide can
      include both
      verbal and
      non-verbal
      information.




6-8
     Nominal Group Technique (NGT)
A facilitated process that supports idea generation by
groups.
Process
     Members come together as a group, but initially work
      separately.
     Each person writes ideas.
     Facilitator reads ideas out loud, and they are written on
      blackboard.
     Group discusses the ideas.
     Ideas are prioritized, combined, selected, and reduced.




6-9
             Other Approaches
What is Direct Observation?
    Watching users do their jobs
    Can provide more accurate information than self-
     reporting (like questionnaires and interviews)
What is Document Analysis?
    Review of existing business documents
    Can give a historical and “formal” view of system
     requirements




6-10
Analyzing Procedures and Other
          Documents
Four types of useful documents
    Written work procedures
        Describes how a job is performed
        Includes data and information used and created in the
        process of performing the job or task
    Business form
        Explicitly indicate data flow in or out of a system
    Report
        Enables the analyst to work backwards from the report
        to the data that generated it
    Description of current information system
6-11
       Written work
       procedure is
       a business
       document
       that formally
       describes
       work
       processes,
       provides
       useful
       information
       regarding
       system
       functionality
       and logic.


6-12
       Business form
       is a document
       that contains
       useful
       information
       regarding data
       organizations
       and possible
       screen
       layouts.




6-13
          Report
        Example:
       Statement of
        Cash Flow




6-14
       Contemporary Methods for
       Determining Requirements
Joint Application Design (JAD)
   JAD with CASE tools
Prototypes of the system




6-15
  Joint Application Design (JAD)
Intensive group-oriented requirements
determination technique
Team members meet in isolation for an
extended period of time
Highly focused
Resource intensive
Started by IBM in 1970s




6-16
       Layout of a typical JAD Session




6-17
       Joint Application Design (cont.)
End Result
    Documentation detailing existing system
    Features of proposed system
CASE tools During JAD
    Enables analysts to enter system models directly
     into CASE during the JAD session
    Screen designs and prototyping can be done
     during JAD and shown to users




6-18
                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




6-19
Business Process Reengineering
            (BPR)
Search for and implementation of radical
change in business processes to achieve
breakthrough improvements in
products/services
Goals
   Reorganize complete flow of data in major sections
    of an organization
   Eliminate unnecessary steps
Disruptive technologies
  Netflix (new movie rental model)
 Apple (iPod; iPad as book reader, etc.)
6-20
Agile Methodologies for Requirements
           Determination
 Continual user involvement
     Replace traditional SDLC waterfall with iterative analyze –
      design – code – test cycle
 Agile usage-centered design
     Focuses on user goals, roles, and tasks
     Details next




 6-21
       Continual User Involvement




6-22
Agile Usage-Centered Design Steps
Gather group of programmers, analysts, users,
testers, facilitator
Document complaints of current system by users
Determine important user roles (users & their goals)
Determine, prioritize, and describe tasks for each
user role
Group similar tasks into interaction contexts (i.e. 3x5
stacks of task cards containing important, frequent,
and similar tasks that users mentioned)
Associate each interaction context with a user
interface for sys., & prototype the interaction context
   First tasks are turned into paper-and-pencil prototype
    before the meeting is over.
   Requirements captured from users and developers turn
    them into prototyped systems screen
Step through and modify the prototype
        Boeing: User Involvement
        and Agile Methodologies
Wire Design & Wire Install systems for 757
   System supports engineers who customize plane
    configurations for customers
      Allowing them to analyze all 50,000 wires that can be
      installed on a 757
   1st attempt to build such a system took 3 years
      and the resulting system was never used
   In 2nd attempt & relying on Agile methodologies
      System took 6 weeks to build
      Important reason for success was a user liaison between
      developers and end users
        i.e. continual user involvement

				
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