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    Sylnovie Merchant, Ph.D. MIS 210 Fall 2004

    Lecture 2:

    SDLC

    Methodologies

    Project Initiation and Planning

    Requirements Analysis

    MIS 210

    Information Systems I

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    Systems Development

    Life Cycle(SDLC)

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    Systems Development

    What is a system?

    A collection of related components that interact

    to perform a task in order to accomplish a goal

    Systems development (systems analysis and

    design) is the process of creating systems,

    developing them, and maintaining or enhancing

    them.

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    Characteristics of Software

    Software is developed, not manufactured

    Software does not wear outalthough it can become obsolete

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    Todays Software Development

    Environment

    Failures

    Productivity gap

    Backlogs

    Maintenance bound

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    Alleviating the Problems in

    Systems Development

    Elimination of the causes of system failure lie in

    1. the application of methodologies

    2. modeling tools

    3. techniques

    4. project management techniques

    to design and build IS that not only meet the needs of the

    users, but also are delivered on time and within budget

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    Principles of Successful Systems Development

    Get the user involved

    Use a problem-solving approach

    Establish phases and activities

    Establish standards for development and documentation Justify systems as capital investments

    Don't be afraid to cancel or revise scope

    Divide and conquer

    Design systems for growth and change

    Proper planning and project management

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    Some Key Terms ...

    Systems development life cycle (SDLC): the life of a project,from concept through implementation

    Methodology: a comprehensive and detailed version of anentire SDLC

    Technique: an approach that applies specific tools and rules tocomplete one or more phases of the methodology

    Modeling tools: specific tools used to apply techniques

    Project management techniques: tools used to help plan,schedule, and control a project

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    Tools

    Software support that helps create models

    or other project components

    From simple drawing programs to complexCASE tools

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    Some Tools

    Project management applications

    Drawing/graphics applications

    Word processing/text editor

    Computer-aided system engineering (CASE) tools

    Integrated development environment (IDF)

    Database management applications

    Reverse-engineering tool

    Code generators

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    Techniques

    Collection of guidelines that help the analyst

    complete a system development activity or task

    Step-by-step instructions

    General advice

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    Some Techniques

    Strategic planning

    Project management

    User interviewing

    Data-modeling

    Relational database design

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    Systems Development Lifecycle (SDLC)

    Three major activitiesAnalysis: understanding business needs

    Design: conceptualizing computer-system

    solutionImplementation: construction, testing, and

    installation

    Two additional phasesProject planning

    Support

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    The SDLC

    1. Planning

    a. Project identification and selection

    b. Project initiation and planning

    2. Analysis

    a. Determine system requirements (WHAT users need)b. Modeling possible solutions (HOW to satisfy user needs)

    3. Design

    a. logical design

    b. physical design4. Implementation

    5. Maintenance / support

    F

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    d

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    D

    I

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    SDLC Concepts

    All projects use some variation of the SDLC

    SDLC is more than phases

    Principles of management

    Planning and control

    Organization and scheduling

    Problem solving

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    Major Attributes of the Life Cycle

    The project --

    Moves systematically through phases where

    each phase has a standard set of outputs

    Produces project deliverables

    Uses deliverables in implementation

    Results in actual information system

    Uses gradual refinement

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    Project Phases

    Planning (Why build the system? How should

    the team go about building it?)

    Analysis (Who uses system, what will it do,

    where and when will the system be used?)

    Design (How will the system work?)

    Implementation (System delivery)

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    Identifying business value

    Analyze feasibility

    Develop work plan Staff the project

    Control and direct project

    Planning

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    Design selection

    Architecture design

    Interface design Data storage design

    Program design

    Design

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    Construction

    Program building

    Program and system testing

    Installation

    Conversion strategy

    Training plan

    Support plan

    Implementation

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    Support Phase

    Objective: Keep system running productively

    following initial installation

    End-user support

    Help desks

    Training programs

    Maintaining and enhancing computer system

    Enhancements

    Upgrades Maintenance

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    Methodologies

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    Common Development Methodologies

    and Techniques

    Code & fix model

    Structured development

    Prototyping

    Rapid application development

    Object-oriented development

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    Code and Fix It Model

    An early technique

    The developer, in the following order:

    codes

    thinks about requirements

    fixes the code

    continues this process until...

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    Structured Development

    Based on the principles of:

    modularization

    top-down decomposition

    process driven

    Structured programming

    Structured design

    Structured analysis

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    Systems Development Life Cycle

    Waterfall Model

    Project Identification

    and Selection

    Project Initiation

    and Planning

    Analysis

    Logical Design

    Physical Design

    Implementation

    Maintenance

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    Waterfall Model

    Problems

    dependent on documents, particularly in

    completing the requirements and design phases

    tendency to hide poorly understood requirements

    with elaborate specifications

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    Advantages of Structured Development

    Been used successfully for over 30 years

    Provides a clear framework that defines and

    divides important activities

    Can be applied to both small and large projects

    Division of labor is easier to facilitate

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    Limitations of Structured Development

    Specification problemsassumes that development is a sequential

    process

    Changing requirements

    requirements specified at the beginningassumption that requirements will not change

    Conceptualization and visualization

    document led methodologyvolume of documentation can be huge

    Inaccuracy

    there is only downward trend

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    Prototyping

    Principle: a user can tell you better what they DON'T wantthan what they DO want

    Expendable (throw-away) prototyping:

    discarded after use

    used to support the analysis and design phases

    Evolutionary prototyping:

    prototype evolves into the final system

    is it a methodology?

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    Advantages Speed

    Easier for end-users to learn

    System changes discovered earlier

    End-user involvement (ownership) increased user satisfaction increased user acceptance

    User-analyst communication

    Early problem detection reduced development time

    reduced maintenance

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    Disadvantages

    Poor documentation

    Hard to control/manage

    (Unrealistic) User expectations

    time for final system

    final system differences

    reduced analysis

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    Rapid Application Development

    (RAD) Logistical approach to systems design

    Combines

    integrated CASE toolsinformation engineering methodologies

    management techniques

    Speeds up Systems Development by as much as20 times

    Critics consider it incomplete life cycle

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    Object-Oriented (OO) Development

    A fundamentally new way of thinking aboutdeveloping systems

    Object-oriented: means that we organizesoftware as a collection of discrete objects thatincorporate both data and behavior

    Object-oriented development: an approach

    to systems development that proposes the useof objects in the building of new systems andthe rebuilding of old ones

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    Advantages of OO

    Faster development

    Higher quality

    Easier maintenance

    Increased scalability Better information structure

    Increased adaptability

    Increased modeling power Supports complexity

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    Disadvantages of OO

    Maturity of technology

    Need for standards

    Lack of database technology

    Lack of reusable software Lack of metrics

    Speed of execution

    Availability of qualified personnel Cost of conversion

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    Project Initiation and Planning

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    Project Initiation and Planning

    Long-term information systems strategic plan(top-down)

    Department managers or process managers

    (bottom-up)

    Response to outside forces

    Legislative changesMarket forces

    Competition

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    Confirming Project Feasibility

    Economic

    Organizational and cultural

    Technological

    Schedule

    Resource

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    Intangibles in Economic Feasibility

    Costs and benefits cannot always be measured

    Examples

    Increased levels of service

    Survival

    Lost customers or sales

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    Organizational and Cultural Feasibility

    Each company has own culture

    New system must fit into culture

    Evaluate related issues for potential risks

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    Technological Feasibility

    Does system stretch state-of-the-art?

    Does expertise exist in-house for development?

    Does a third party need to be involved?

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    Schedule Feasibility

    Can project be completed on time?

    Risk of schedule slipping

    Assumptions and estimates

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    Resource Feasibility

    Team member availability

    Team skill levels

    Equipment

    Support staff

    Physical facilities

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    Developing Project Schedule

    Task: smallest piece of work

    Activity: group of tasks

    Phase: group of activities

    Schedule processList all tasks for each SDLC activity

    Estimate sizes of each task

    Determine task sequenceSchedule tasks

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    Project Staffing

    Develop resource plan for the project

    Identify and request specific technical staff

    Identify and request specific user staff

    Organize the project team into work groups

    Conduct preliminary training and team buildingexercises

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    Launching Project

    Oversight committee is finalized and meets to give

    go-ahead

    Formal announcement made

    Key question, Are we ready to start?

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    Focusing the Investigation

    Most system problems occur in complex

    tasks that have high user impact

    Application complexity

    User impact

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    Requirements Analysis

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    Analysis

    A. Determine system requirements

    B. Structure requirements

    1. Process modeling 2. Logic modeling

    3. Data modeling

    C. Select best alternative

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    Requirements Analysis Goals

    Fully describe the current system

    Study and analyze the current system (gather

    and study facts) Determine the ideal information system

    Identify resource constraints

    Define and prioritize requirements

    Inspire user confidence/ownership

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    Study & Analyze Current System

    Gather information on what the system should

    do from as many sources as possible

    Concentrate on WHAT is needed, not HOW to

    do it

    Dont try to fix it unless you understand it

    Major problem: analyst not understanding

    user needs

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    Study & Analyze Current System

    -- Activities --

    1. Learn about current system (gather facts)

    2. Model current system

    3. Analyze problems/opportunities (study facts)

    4. Establish new system objectives

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    Study & Analyze Current System

    -- Output --

    1. Complete statement of user environment

    2. Models of current system

    3. List of major problems/causes/effects

    4. System objectives

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    Learn About Current System

    (gather facts)

    Gather information from:

    Current information system:

    a current IS may exist

    External sources: reviewing other IS outside the organization can

    reveal practical ideas and techniques

    Internal sources:

    single most important source of facts is the user

    existing paper work or documents is also agood source

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    Tactics

    Listen - dont lecture

    Dont pre-solve problem

    Compare stories

    Look for reluctant responses

    Observe your effects on system

    Avoid politics (head nodding)

    Expect hard, boring work

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    Fact-finding Methods

    Research and site visits

    Existing documentation

    Observation

    Questionnaires

    Interviews

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    Observation

    Not for long periods of time

    will change what your measuring

    Vary observation periods

    Take only minimal, preplanned notes Coordinate visit beforehand

    Beware of Selective Perception!!!

    Q i i

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    Questionnaires-- Types --

    Open-ended (free format)

    Closed-ended (fixed format)

    multiple choice

    rating

    ranking

    single fact

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    Questionnaire Development

    1. Determine what facts need to be collected

    2. Determine whether free- or fixed-format is best. Usually, a

    combination is used.

    3. Write the questions. Examine them carefully. Make sure

    the questions don't reflect your personal biases.

    4. Test the questions on a small sample of respondents.

    Modify those questions that respondents had problemswith.

    5. Duplicate and distribute the questionnaire.

    Q i i h G d d h B d

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    Questionnaires - the Good and the Bad

    Advantages Can be quickly answered. Cheap for gathering data from a large number of users.

    Allow users to maintain anonymity.

    Responses can be tabulated and analyzed quickly.

    Disadvantages

    Number of respondents is often low. No guarantee that the user will answer all the questions.

    Inflexible - voluntary information is stifled.

    Elimination of body cues.

    No immediate opportunity to clarify an answer.

    Good questionnaires are difficult to prepare.

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    Interviews

    Types of Interviews1. Unstructured

    2. Structured

    Types of Questions1. Open-ended

    2. Closed-ended

    Focus of Questions

    1. Decision analysis2. Data analysis

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    How to Conduct an Interview

    1. Select interviewees. Learn as much as you can about

    interviewee.

    2. Make an appointment - never 'drop by'

    3. Limit the interview to between 1/2 hour and 1 hour

    4. Clear it with the interviewee's supervisor

    5. Conduct the interview in a private location

    6. Prepare for the interview: provide an interview agenda

    7. Conduct the interview: opening, body, conclusion8. Follow-up

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    Make the user feel important

    Be courteous and professional

    Dont take exhaustive notes

    Use structured questions

    Dont ask users to remember details

    Avoid gang interviews

    More Interviewing Tips

    I i h G d d h B d

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    Interviews - the Good and the Bad

    Advantages

    Users are actively involved SA can probe for more feedback from user

    SA can reword questions for each interviewee

    Body cues

    Disadvantages

    Very time consuming, thus very costly

    Success of the interview is dependent on the SA'shuman relations skills

    Interviewing may be impractical due to location ofinterviewees

    O ll S f i di

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    Overall Strategy for Fact Finding

    1. Learn all you can from existing documents

    2. If appropriate, observe the system in action

    3. Conduct interviews

    4. Use questionnaires to clear up things you don't

    fully understand

    5. Follow-up

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    Some Questions That Must be Answered

    What are the inputs to this system?

    What are the outputs of this system?

    What is the business process (i.e., how is data

    processed)?

    Who are the direct end-users?

    How will the users feel about this system? Who developed the existing system?

    Analyze Problems / Opportunities

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    Analyze Problems / Opportunities(study facts)

    Study and analyze the "current" system

    Problem analysis is difficult. We often try to solve problems without analyzing them.

    We try to state the problem in terms of a solution.

    Use the PIECES framework to frame your investigation ofthe problems, opportunities, and requirements

    Performance analysis Information and data analysis

    Economic analysis

    Control and security analysis Efficiency analysis

    Service analysis

    http://pieces.pdf/http://pieces.pdf/
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    Requirements Analysis Document

    Parts

    How analysis was conducted

    credibility

    restartsUser requirements

    System constraints

    Realistic System ObjectivesDocumentation

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    User Requirements

    User system objectives (unedited)

    Reports (type/frequency)

    User training needs

    Effect of system on various users

    Organization Chart