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    QMIS331:

    InformationSystem

    Analysis and Design

    (ISAD)

    By

    Dr. Abou l El la Hassan ien

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    Lecture Meeting and Location

    Lecture Meeting:

    Saturday

    Monday

    Wednesday

    8.00 8.50

    Location: Room # 311 Office Hours:

    Sat & Monday 9.00 -10.00

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    Required Text Book

    Modern System Analysis & Design, 4th

    Jefferey A. Hoffer, Joey F. George and

    Joseph. S. Valacich, Prentice-Hall,2005

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    Course Objective

    To provideyou with new ways of looking atinformation in the world in order to solve businessproblems

    To introduceyou to concepts and methods of SAD

    To describethe systems development life cycle(SDLC)

    To teachyou effective methods for gatheringessential information during system analysis

    To teach youeffective methods for designingsystemsto solve problems effectively usingtechnology

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    Chapter-1:The Systems Development Environment

    Basic concepts of IS

    System analysis and design definition

    SAD:Discuss modern approach

    Discuss Organizational Roles System analyst

    Information system types

    SDLC:The System Development Life Cycle

    Using CASEtools (Computer Aided SoftwareEngineering)

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    Systems Theory

    What is a System?

    Systems and Subsystems

    Business organization as a Socio-technical system

    Information Systems (IS) as a

    system

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    What is a System?

    A collection of partsthat work together toachieve a goal/task Examples

    Solar system

    Digestive systems Public transport system

    Central heating system

    Computer system

    Information system

    A set of objectsand relationships amongthe objects viewed as a whole anddesigned to achieve a purpose

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    SystemsCan Be Composed of Subsystems

    Subsys A-2

    Subsys A-3

    SubsysB-2

    SubsysB-1

    System

    Subsys A Subsys B Elemental

    Part C

    Subsys A-1

    Elemental

    part B1

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    What is subsystem?

    A subsystem is simply a systemwithin a system.

    Automobile is a system composed of

    subsystems: Engine system

    Body system

    Frame system

    Each of these subsystem iscomposed of sub-sub --systems. Engine system: carburetor system,

    generator system, fuel system, and soson

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    Bad Systems

    Fail to meet requirements

    Poor performance

    Poor reliability

    Lack of usability

    Example difficulties: Not to schedule

    Not to budget

    Runaway = 100% over budget or schedule

    Some problems are simply wickedproblems

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    Reasons for Failure

    Complexity Shifting requirements

    Bad estimation

    Bad management

    New technology

    Must tackle complexity by, for example: Structure partitioning of problem

    Organized interaction of parts

    Ensure you achieve the task

    Systems are subject to the need forcontinuing change

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    Important System Concepts

    Decomposition

    The process of breaking down asystem 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 toone group of users

    Build different components atindependent times

    1.14

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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 uponeach other are coupled

    Cohesion Extent to which a subsystem

    performs a single function

    1.14

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    Computer-based Information Systems (CBIS) vs

    Manual Systems

    CBIS

    Information system that rely on

    computer hardware and software for

    processing and disseminatinginformation

    Manual systems

    Use paper + pencil technology

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    CBIS Components

    A Computer-based Information System

    = Hardware + Software + People +Procedures + Information

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    Data and Information

    Data are raw facts about the organization

    and its business transactions. Most data

    items have little meaning and use by

    themselves.

    Alternative definition: Data are a collection of items such as words,

    numbers, images, and sounds that are not

    organized and have little meaning individually

    Data are raw facts about people, objects, and

    events in an organization

    information: Data that is organized

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    Data flow andprocessing logic

    Data flow:

    Data in motion, moving from one place in a

    system to another

    Processing logic:The steps by which data are transformed or

    moved and a description of the events that

    trigger these steps

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    Processing logic example

    Events: H-W = 0

    Event-action:

    If H-W > 40 thenPay = 40 *Pay-rate + (H-W40 ) *(1.5 *Pay-rate)

    Else

    Pay = Pay-rate *H-W

    End if

    -- H-W . Worked Hours

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    Databases

    A shared collection of logically

    related data designed to meet the

    information needs of multiple users

    in organization.DatabaseFilesRecords-- Fields

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    Levels of data managements

    databases

    File 1 File 2File

    N

    Record 1 Record 2 Record N

    Filed 1

    Filed 2

    Filed N

    Character BYTE

    Character BYTE

    Character BYTE

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    Traditional vs database approach

    Traditional approach

    Personal

    dataProject

    data

    Tax

    data

    Personal

    data

    Payroll

    systemProject

    Management System

    Redundant data

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    Traditional vs database approach

    Database approach

    Tax

    data

    Personal

    data

    Payroll

    system

    Project

    Management System

    Project

    data

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    Approach to system development

    There are three strategies of IS

    development

    1. Process-oriented approach

    2. Data-oriented approach

    3. Object-oriented approach

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    Process-oriented approach

    An strategy to IS development that focuses on how andwhen data are moved through and changed by an IS

    Data-oriented approach An strategy to IS development that focuses on the ideal

    organization of data rather than where and how data are

    used.

    Object-oriented approach A system development methodologies and techniques

    base on objects rather than data or process

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    Application independence

    The separation of data and the definition of data from

    the applications that the use these data

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    Example

    Rent books system Rent house system

    Personal

    data

    Book

    data

    Personal

    data

    House

    data

    Link

    Is missing

    Rent books system Rent house system

    Book

    data

    Personal

    data

    House

    data

    Application

    independenc

    Process Oriented Approach

    Data oriented

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    What is an Information Systems?

    Interrelated components working

    together to

    Collect

    Process

    Store

    Disseminate information

    To support decision making,coordination, control, analysis and

    visualization in an organization

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    A SYSTEM THAT PROVIDES THE INFORMATION NEEDED TO

    ACCOMPLISH THE ORGANIZATIONS TASKS

    WHAT IS A COMPUTER BASED

    INFORMATION SYSTEM?

    A SYSTEM THAT USES COMPUTERS TO

    PROVIDE THE NEEDED INFORMATION

    What is an Information System?

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    Information System Types

    1. Transaction Processing Systems (TPS)

    2. ManagementInformation Systems

    (MIS)3. Decision Support Systems (DSS)

    4. Expert System andArtificial Intelligence

    (ES &AI)

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    Transaction Processing Systems

    (TPS)

    TPS are computerized information systems that weredeveloped to process large amounts of data for routine

    business transaction.

    Automate the handling of data aboutbusiness activities

    and transactions, which can be thought of a simplediscrete events in the life of an organization.

    Data about each transaction are captured,

    Transactions are verified and accepted/rejected,

    Validation transactions are stored for later aggregation.

    Report may be produced to provide summarization of thetransactions, and

    Transaction may be moved from process to process in order tohandle all aspects of the business activities.

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    Management Information Systems

    (MIS) Information system at the management level of an

    organization that serves the functions of planning,

    controlling, and decision making by providing routine

    summary and exception reports.

    It takes the relatively raw data available through a TPSand converts them into a meaningful aggregated form

    that mangers need to conduct their responsibilities.

    Developing an MIS calls for a good understanding of

    what kind of information managers require and howmanagers use information in their jobs.

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    Expert System and Artificial

    Intelligence (ES & AI)

    Knowledgerepresentation describes the way an expert would

    approach the problem. It attempts to codify and manipulate

    knowledge rather than information, (for example if .. Then rule)

    User communication with an ES via an interactive dialogue.

    The ES asks questions ( that an expert would ask) and the end user

    supplies the answers.

    The answers are then used to determine which rules apply and the

    ES provides a recommendation based on the rule.

    Knowledge Engineers perform knowledge acquisition; they aresimilar with system analyst but are trained to use different

    techniques.

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    System development for different

    IS types

    1- TIS

    IS characteristic:

    High volume, data capture focus

    System development methods: Process-oriented

    Concern with capturing, validating, and

    storing data with moving data between

    each required step

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    System development for different

    IS types

    3- DSS

    IS characteristic:

    Provide guidance in identifying problem, finding

    and evaluating alternative solutions and selecting

    or comparing alternatives; potentially involvesgroups of decision making

    System development methods:

    Data- and decision logic orientation

    Design of user dialogue; group communication

    may be key an access to unpredictable data may

    be necessary

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    System development for different

    IS types

    4-ES

    IS characteristic:

    Provide expert advice by asking users a

    sequence of questions dependent on prioranswers that lead to a conclusion or

    recommendation

    System development methods:

    A specialized decision logic orientation inwhich knowledge is elicited from experts

    and described by rule or other form

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    Stakeholders: Players in theSystems Game

    A stakeholderis any person who

    has an interest in an existing or

    new information system.

    Stakeholders can be technical or

    nontechnical workers.

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    Stakeholders Classification

    For information systems, thestakeholders can be classified as:

    IS manger

    Systems analystsin systems development Programmers in systems development

    End userin systems development

    Supporting End userdevelopment

    Business managersin systems development Other IS mangers/Techniciansin system

    development

    IS M i S

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    IS Manger in Systems

    Development

    The manager of an IS department may have a direct rolein the systems development process if the organization issmall or I that is the mangers style

    IS mangers are more involved in allocating resources toand overseeing approved system development projectsrather than in the actual project development process.

    There are several IS mangers in any medium to large ISdepartment.

    The manger of an entire IS department may have the title Chief

    Information Officer and may report to the president or chairmanof the firm.

    Each division of the IS department will also have a manger

    Director of IS development, IS operation manger, IS programmerdirector, etc.

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    Systems Analysts

    Systems analysts are the key individuals in thesystems development process.

    A systems analyst studies the problems and needs

    of an organization to determine how people, data,processes, communications, and informationtechnology can best accomplish improvements for thebusiness.

    The organizational role most responsible for the

    analysis and design of information systems.

    Skill f S f l S t

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    Skills of a Successful Systems

    AnalystAnalytical skills

    Understanding of organizations.

    Problem solving skills

    System thinking Ability to see organizations and

    information systems as systems

    Technical skills Understanding of potential and

    limitations of technology.

    1.45

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    Skills of a successful systems

    analyst Managerial skills

    Ability to manage projects, resources, risk and

    change

    Interpersonal skills

    Effective written and oral communication skills Help you work with end user as well as other

    system analysts and programmers

    1.46

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    V i ti th S t

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    Variations on the Systems

    Analysts TitleA business analystis a systems analyst that

    specializes in business problem analysis

    and technology-independent requirements

    analysis.

    A programmer/analyst includes the

    responsibilities of both the computer

    programmer and the systems analyst.

    Others Systems consultant

    Systems engineer

    Information engineer

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    The Systems Analyst as a Facilitator

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    Skills Required by Systems Analysts

    Working knowledge of informationtechnology

    Computer programming experience and

    expertise

    General business knowledge Problem-solving skills

    Interpersonal communication skills

    Interpersonal relations skills

    Flexibility and adaptability

    Character and ethics

    Systems analysis and design skills

    Programmers in systems

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    Programmers in systems

    development Programmers convert the specifications given to them by

    the analysts into instructions the computer can

    understand.

    Coding: writing a computer program

    Code generatorshave been developed to generate codefrom specifications, saving an organization time and

    money.

    The aim of CASEtools (Computer-Aided Software

    Engineering) is to provide a variety of code generatorsthat can automatically produce 90% or more from the

    system specifications normally given a programmer.

    B i i t

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    Business managers in system

    development

    Another group to system development efforts is business

    managers such as functional department heads and

    corporate executives.

    These managers are importantbecausethey have the

    power to fund development projects and to allocate

    resources necessary for projects success.

    Oth IS / T h i i

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    Other IS managers/ Technicians

    in system development

    Database ----- database administrator

    Network and telecommunications experts:

    Manager of Data Communication

    Manager of Voice Communication

    Internal auditors

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    Characteristics of successful teams

    The characteristics are diversity inbackgrounds,

    skills, and goals;

    tolerance of diversity, uncertainty, and

    ambiguity;

    clear and complete communication;

    trust;

    mutual respect and putting one's own viewssecond to the team;

    A reward structure that promotes shared

    responsibility and accountability.

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    System Analysis and Design

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    System Analysis and Design

    (SAD)

    Analysis: defining the problem

    From requirements to specification

    Design:solving the problem

    From specification to implementation

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    Why is it important?

    Success of information systemsdepends on good SAD

    Widely used in industry - proven

    techniques

    Part of career growth in IT - lots of

    interesting and well-paying jobs!

    Increasing demand for systemsanalysis skills

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    Views of Systems Analysis

    How to build information systems

    How to analysis information system

    needs

    How to design computer based

    information systems

    How to solve systems problems in

    organizations

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    Systems Development Life

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    Systems Development Life

    Cycle (SDLC) It is a common methodology for systems often follows

    for system development in many organization, featuringseveralphasesthat mark the progress of the systemsanalysis and design effort.

    SDLC phases: 1-Project identification and selection

    2-Project initiation and planning

    3-Analysis

    4-Design

    4.1Logical design 4.2Physical design

    5-Implementation

    6-Maintenance

    1.60

    1 Project identification and

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    1-Project identification and

    selection phase

    The first phase of the SDLC in which an

    organization total information systems needs

    are identified analyzed, prioritized andarranged.

    Identifying Potential development projects

    Classifying and ranking projects

    Selecting projects for development More details will be discuss in chapter (5)

    Cont

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    Cont.

    1- Project identifying and selection

    This stage is critical to the success ofthe rest of the project.

    People: Users, analyst, system managers coordinating the project

    Activities: Interviewing user management, summarizing the

    knowledge obtained estimating the scope of the project

    and documenting the result

    Output: Feasibility report: problem definition and summarizing the

    objectives

    2 Project initiation and planning

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    2-Project initiation and planning

    phase

    The second phase of the SDLC in which a

    potential IS project is explained and an

    argument for continuing with the project ispresented. A detailed plan is also developed

    for conducting the remaining phases of the

    SDLC for the propose system. Output are:

    Detailed stepwork plan - high level systemrequirementassignment of team members

    More details will be discuss in chapter (6)

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    3-Analysis phase

    The third phase of the SDLC in which thecurrent system is studied and alternativereplacement systems are proposed.

    Description of current system Where problem and opportunities are with a general

    recommendation on how to fix, enhance or replacecurrent system

    More details will be discuss in chapters (7-11)

    Cont

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    Cont.

    3- Analyzing systems needs

    The primary objective of the analysis phase is tounderstand and document the business needs andthe processing requirements of the new system.There are six primary activities in this phase:

    Gather information.

    Define system requirements.

    Build prototypes for discovery of requirements .

    Prioritize requirements.

    Generate and evaluate alternatives.

    Review recommendations with management

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    4-Design phase

    The forth phase of the SDLC in which the descriptionof the recommended solution is converted intological and then physical system specification.

    Logical design:

    The part of the design phase of the SDLC in which allfunctional feature of the system chosen fordevelopment in analysis are described independently ofany computer platform.

    Physical design:

    The part of the design phase of the SDLC in which thelogical specification of the system from logical designare transformed into technology specific details from

    which all programming and system construction can beaccomplished.

    More details will be discuss in chapter (12-16)

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    4.1 Logical design output

    Functional,

    Detailed specification of all system

    elements Input

    Output

    Process

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    4.2 Physical design output

    Technical

    Detailed specification of all system

    elements

    programs, files,

    network,

    system software

    etc

    Acquisition plan of a new technology

    Cont

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    Cont.

    4- Designing the recommended system

    Its primary objective is to convert the description of therecommended alternative solution into system specification.

    High-level design consists of developing an architecturalstructure for software programs, databases, the user interface,and the operating environment.

    Low-level design entails developing the detailed algorithms anddata structures that are required for program development.

    Seven major activities must be done during design: Design and integrate the network.

    Design the application architecture.

    Design the user interfaces . Design the system interfaces.

    Design and integrate the databases.

    Prototype for design details.

    Design and integrate the system controls

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    5- Implementation

    The fifth phase of the SDLC in which theinformation system is

    Coded,

    Tested,

    Installed, and Supported in the organization.

    Outputs:

    Code, documentation, training procedures and

    support capabilities

    More details will be discuss in chapter (17)

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    6-Maintances

    The final phase of the SDLC in which theinformation system is systematically repaired

    and improved

    Output are:

    New versions of releases of software with

    associated updates to documentation, training, and

    support

    More details will be discuss in chapter (18)

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    Disadvantages of traditional SDLC

    It is too expensive (cost + time) whendealing with change once it is developed

    It is structured approaches that requires to

    follow all its phases

    Maintains costs are too expensive

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    1- Structured analysisand structured

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    St uctu ed a a ys s a d st uctu ed

    design

    More focus on reducing maintenances and

    time effort in system development

    Integrate change when needed

    2- Object Oriented Analysis and

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    2 Object Oriented Analysis and

    Design (OOAD)

    A more recent approach to systemdevelopment that is becoming is object

    oriented analysis and design (OOAD).

    It is often called thirdapproach to system

    development, after theprocess orientedand

    data orientedapproaches

    Definition: OOAD

    It systems development methodologies andtechniques base on objectsrather than dataor

    process

    bj h i d bj l

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    Object, Inheritanceand object class

    Object:A structure that encapsulates (packages)

    attributes and methods that operate on those

    attributes. An object is an abstraction of a realworld thing in which data and processes are

    placed together to model the structure and

    behavior of the real world object

    Combine data and processes (called methods)into single entities called Object

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    I h i

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    Inheritance

    The property that occurs when entity types or

    object classes are arranged in a hierarchy and

    each entity type or object class assumes the

    attributes and methods of its ancestors.

    3 P t t i

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    3- Prototyping

    An iterative processof systems development inwhich requirementsare converted to a workingsystemthat is continually revised through closework between an analyst and users.

    You can build prototype by some developmenttool to simplify the process. CASE: Computer Aided Software Tools such as

    Oracle (designer 2000)

    4GLs: fourth-generation languages Prototyping is a form of Rapid Application

    Development (RAD)-------- Chapter 10

    RAD di d

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    RAD disadvantages

    1. RAD may overlook software

    engineering principles,

    2. Resulting in inconsistencies amongsystems modules,

    3. Noncompliance with standards, and

    4. Lack of system component reusability

    Th t t th d l

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    The prototype methodology

    If prototype

    inefficient

    Convert to

    Operational syst.

    Identify

    problem

    Implement &

    Use prototypeRevise& enhance

    prototype

    Develop

    prototype

    Initial requirement

    Problems

    Next Version

    Working prototype New

    requirement

    Th t t th d l

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    The prototype methodology

    1. The analyst work with team to identify theinitial requirement for the system:

    2. The analyst then build the prototype. When

    a prototype is completed, the users work

    with it and then tell the analyst what they

    like and do not like about it.

    3. The analyst uses this feedback to improve

    the prototype4. Take the new version back the users

    5. Repeat (2-4) until the users satisfied

    P t t d t

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    Prototype advantages

    1. Prototyping involves the user in analysisand design

    2. its ability to capture requirements in

    concreterather than abstractform3. To being used stand alone

    4. It is may be used to augmentthe SDLC

    Wh I P t t

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    When I use Prototype

    1. User requirements are not clear

    2. One or few users and other stakeholders are

    involved with the system

    3. Possible designs are complex and requireconcrete form to fully evaluate

    4. Communication problem have existed in the

    past between user and analysts

    5. Tools and data are readily available to

    rapidly build working systems

    4 J i t A li ti D i (JAD)

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    4-Joint Application Design (JAD)

    In the late 1970 systems developmentpersonnel at IBM developed a new

    process for collecting IS requirements and

    reviewing system design. It is called JADDefinition: It is structured process in

    which users, mangers, and analysts work

    together for several days in a series ofintensive meeting to specify or review

    system requirements

    5 P ti i t d i

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    5- Participatory design

    End users are involved in the SD around a

    table in one room to agree about system

    requirements and system designThey responsible about the freeze of

    design Milestone

    Automated Tools and

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    Automated Tools and

    Technology

    Analyst rely on automated tools to:

    Increase productivity

    Communicate more effectively with users

    Integrate the work that they do on the system frombeginning to the end of the life cycle

    Examples:

    Computer-Aided Systems Engineering (CASE -tools)

    Application Development Environments (ADE -tools)

    Process and Project Managers

    Improve productivity of IS

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    p p y

    development

    Computing technology can be used to

    improve productivity. CASE tools, forexample, provide many productivity

    enhancing capabilities, such as code

    generation, diagramming tools, and screen

    and report designing tools.

    Computer-Aided Systems

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    p y

    Engineering: CASE tools

    Computer-aided systemsengineering (CASE) tools are

    software programsthat automate or

    support the drawing and analysis ofsystem models and provide for the

    translation of system models into

    application programs.

    Computer-Aided Systems

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    p y

    Engineering: CASE tools

    A CASE repositoryis a system developers database. It

    is a place where developers can store system models,detailed descriptions and specifications, and otherproducts of system development. Synonyms include

    dictionaryand encyclopedia. Forward engineeringrequires the systems analyst to

    draw system models, either from scratch or fromtemplates. The resulting models are subsequentlytransformed into program code.

    Reverse engineeringallows a CASE tool to readexisting program code and transform that code into arepresentative system model that can be edited andrefined by the systems analyst.

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    Chapter -1

    The End