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Systems Analysis And Design 2
 

Systems Analysis And Design 2

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    Systems Analysis And Design 2 Systems Analysis And Design 2 Presentation Transcript

    • Systems Analysis and Design: The Big Picture Computers:Tools for an Information Age
    • Objectives
      • Define the terms “system,” “analysis,” and “design”
      • Describe the principal functions of the systems analyst
      • List and describe the phases of the systems development life cycle
      • Describe the various data-gathering and analysis tools
      • Describe a selection of systems design tools
      • Explain the concept of prototyping
      • Explain the role of the maintenance task in the systems development life cycle
    • Systems Analysis Design
      • System – an organized set of related components established to accomplish a certain task
        • Computer system – a system that has a computer as one of its components
      • Analysis - Studying an existing system to determine how it works and how it meets users’ needs
        • Typically happens as a result of some impetus for change, combined with the authority to make the change
      • Design - The process of developing a plan for an improved system, based on the result of the systems analysis
    • Who Participates? Project Team
    • Key Individuals Involved in Systems Analysis
      • Systems analyst – performs analysis and design
        • May perform some programming as well
      • Client – the person or organization contracting to have the work done
      • User – the people who will have contact with the system
    • Systems Analyst: A Change Agent
      • The catalyst or persuader who overcomes the reluctance to change within an organization
      • Systems analyst can function as change agent, but it works best if it is someone inside the organization
      • What it takes:
        • Coordination of many people, tasks, and schedules
        • Communication skills, both oral and written
        • Planning and design (an analytical mind)
          • Self-discipline and self-direction
          • Good organizational skills
          • Creativity
          • The ability to work without tangible results
    • System Development Life Cycle (SDLC)
      • Organized set of activities that guides those involved through the development of an information system.
      • Phases
        • Preliminary Investigation
        • Analysis
        • Design
        • Development
        • (Documentation)
        • Implementation
      • Ongoing activities
        • Project management
        • Overall Documentation
        • Information gathering
    • Systems Development Life Cycle
      • Documentation
      • Preliminary Investigation
      • Or feasability study
      • Problem Definition
      • Development and testing.
      • Scheduling
      • Programming
      • Implementation
      • Training
      • Conversion
      • Evaluation
      • Maintenance
      • Analysis
      • Gather data
      • Analyze data
      • Develop requirements
      • Design
      • Preliminary design
      • Detail design
      • Ongoing Activities
      • Project Management
      • Documentation
      • Information Gathering.
    • System Development Guidelines Use a structured approach Involve the Users Develop Standards
    • Ongoing Activity: Project Management
      • The process of planning, scheduling, and controlling activities during the SDLC
      • Scope (goal, objectives, expectations)
      • Activities and Deliverables to be completed
      • Time estimates
      • Cost estimates
      • Order activities occur
      • Activities performed concurrently
      Gantt Chart Project Plan
    • Ongoing Activity: Feasibility Assessment
      • Measure of how suitable the development of a system will be in the organization. (Initially occurs in the Preliminary Investigation phase but needs to be continuously reevaluated)
        • Operational feasibility
        • Schedule feasibility
        • Technical feasibility
        • Economic or cost/benefit feasibility
    • Ongoing Activity: Documentation
      • Compilation and summarization of data and information
        • Reports
          • Diagrams
          • Programs
          • Other deliverables generated during SDLC
        • Project Notebook
        • Project Dictionary/Repository
    • Ongoing Activity: Data & Info Gathering
      • Review current system documentation
      • Observe
      • Send Questionnaires
      • Interview
        • Structured/Unstructured
      • Conduct JAD (joint application design) sessions
      • Research
      Begins in Analysis Phase, but is continually updated
    • Phase 1: Preliminary Investigation
      • A brief study of the problem to determine whether the project should be pursued
        • Also called the feasibility study or system survey
        • Involves working with the users
        • Organization chart – a hierarchical drawing showing the organization’s management
    • Feasibility Study
      • Technical feasibility
      • Economic feasibility
      • Operational feasibility
        • are the current work practices and procedures adequate to support the new system?
        • Legal feasibility
      • Schedule feasibility
        • how long will the system take to develop, or can it be done in a desired time-frame?
    • Defining the Problem
      • Two points that must be agreed upon
        • The nature of the problem
        • The scope (boundaries) of the problem
      • Agreeing on the problem helps define the objectives of the system
    • Project Request
    • Feasibility Assessment
    • Feasibility Assessment (continued)
    • Phase 2: Analysis
      • Understand the existing system
      • Two tasks are involved
        • Data gathering
        • Data analysis
    • Data Gathering
      • A number of techniques can be used
        • Interviews with users and managers
          • Structured interview – includes only questions that have been written out in advance
          • Unstructured interview – interviewer has a general goal but few, if any questions prepared
        • Examining current business and systems documents and output
          • may include current order documents, computer systems procedures and reports used by operations and senior management
        • Sending out questionnaires
        • Observation of current procedures
          • by spending time in various departments; a time and motion study can show where procedures could be more efficient, or to detect bottlenecks
    • Data Analysis
      • Typical tools for data analysis
        • Entity Relationship diagram
        • Data flow diagram
        • Decision table/Decision Tree
        • Written report
      • Report to management/ customer/ client
    • Entity-Relationship Diagrams (ERD)
      • Tool to graphically represent the associations between entities in the project
      Noun Verb
    • Data Flow Diagrams (DFD)
      • Tool to graphically represent the
      • flow of data in a system
      Process Source Data Flow Data Store
    • Decision Table Decision Tree
    • System Requirements & recommendations
      • A detailed list of things the system must be able to do
        • Highlight problems with current system
        • The design of the new system will be based on these requirements
        • Analyst and management must come to a clear agreement on requirements
        • List of possible solutions
        • Hardware/software recommendations
    • Report to Management
      • Summarizes the problems found in the current system
      • Describes the requirements for the new system, including a cost analysis
      • Makes a recommendation on what course to take next
    • Pre-Design considerations
      • The hardware platform
        • which type of computer, network capabilities, input, storage and output devices
      • The software
        • programming language, package or database
      • The outputs
        • report layouts and screen designs
      • The inputs
        • documents, screen layouts, validation procedures
      • The user interface
        • how users will interact with the computer system
      • The modular design
        • of each program in the application
      • The test plan and test data
      • Conversion plan
        • how the new system is to be implemented
      • Documentation
        • User
        • Technical
    • Phase 3: Design
      • The new system is actually planned
      • Divided into two subphases
        • Preliminary design
          • Several key decisions must be made
        • Detail design specifications
          • Output requirements
          • Input requirements
          • Files and databases
          • System processing
          • System controls and backups
    • Build or Buy?
      • Custom Software
        • Developed by user
        • Developed at user request by outside vendor
      • Packaged Software
        • Horizontal
          • Many org types
        • Vertical
          • Industry specific
      Preliminary
    • Acquire Hardware/Software
      • Technical specifications
      • Solicit vendor proposals
      • Test & evaluate
        • Benchmark Test
      • Make a decision
      Detail
    • Input Output
      • Things to consider
        • The medium (paper, screen, etc.) of the output
        • The types of reports needed and what data is needed for the reports
      • Things to consider
        • The input medium (captured at the source, keyed from source document)
        • The fields needed, how they are laid out on the input screen, etc.
        • Input validation may be necessary
      Detail Requirements
    • Input/Output Design Mockup (User) Layout Chart (Programmer)
    • Files and Databases
      • Things to consider
        • How files are organized
          • Sequentially, directly, or by another method
        • The format of the records making up the data files
      Detail
    • Database Design
      • Table structure definitions & relationships
      • Security
      Detail
    • Program Design Data Entry Program File Hard copy Comment Flow Chart System Processing Detail
    • Phase 4: Development
      • Schedule and monitor the two principal activities
        • Programming
        • Testing
      • There are several project scheduling tools available
    • Programming
      • Prepare program design specifications
      • Use logic flowcharts and pseudocode to facilitate code development
    • Testing
      • Unit testing – verifies that individual program units work
        • Perform testing with test data
      • System testing – determines whether all program units work together as planned
      • Volume testing – uses real data in large amounts
        • Determines whether the system can handle a large volume of data
    • Phase 5: Implementation
      • Steps involved in starting the new system
        • Training
        • Equipment conversion
        • File conversion
        • System conversion
        • Auditing
        • Evaluation
        • Maintenance
    • Training
      • Teach users how to use the system
        • The system will do no better than the people using it
        • Develop user’s manual to aid users who are not familiar with the system
        • Hands-on training is best
    • Equipment Conversion
      • Items to consider
        • Delivery schedules must be coordinated
        • Terminals or personal computers must be networked
        • Devices on the system must be compatible
    • File Conversion
      • If existing files are manual, they must be keyed in or scanned into the system
        • Manual files must be kept current while data is being input into the new system
      • If existing files are computer-based, programs must be written to convert the files into the format needed for the new system
    • System Conversion
      • Four approaches
        • Direct conversion – the user simply stops using the old system and starts using the new one
        • Phased conversion – the system is implemented one part at a time
        • Pilot conversion – the entire system is used by a designated set of users
        • Parallel conversion – the old and new systems are both used until users are satisfied the new system works
    • Conversion Options
    • Auditing
      • Systems to trace data in the system back to a source document
        • Very helpful in tracing security violations
    • Evaluation
      • Determines how well the system is meeting the original requirements, benefits, and budgets
        • Evaluation can be performed by the analyst and someone from the organization
        • Evaluation can also be performed by an independent third party
    • Maintenance
      • An ongoing activity that lasts the lifetime of the system
      • Several types of maintenance activities
        • Enhancements to the system
        • Fix bugs in the system as they are identified
    • Terms to Know: Chapter 14
      • Analysis
      • Benchmark test
      • Build-or-buy decision
      • CASE
      • Cost/benefit analysis
      • Data dictionary
      • Data flow diagram
      • Decision tree/Decision table
      • Deliverable
      • Design
      • Development
      • Direct conversion
      • Documentation
      • Entity-relationship diagram (ERD)
      • Feasibility Assessment/Study
      • Gantt chart
      • Joint application development (JAD)
      • Layout chart
      • Mockup
      • Outsourcing
      • Parallel conversion
      • Phased conversion
      • Pilot conversion
      • Post-implementation system review
      • Preliminary investigation
      • Project dictionary
      • Project plan
      • Prototype
      • RFP, RFQ, RFI
      • Scope
      • System
      • System design
      • System development life cycle-SDLC
      • System testing
      • Systems analyst
      • Unit testing
      • Volume testing
    • If asked, can you…
      • Define the terms “system,” “analysis,” and “design”
      • Describe the principal functions of the systems analyst
      • List and describe the phases of the systems development life cycle
      • Describe the various data-gathering and analysis tools
      • Describe a selection of systems design tools
      • Explain the concept of prototyping
      • Explain the role of the maintenance task in the systems development life cycle
    • Sources
      • Capron; Computers: Tools for An Information Age, 8 th Ed. 2003
      • Pfaffenberger; Computers in Your Future 2003
      • Microsoft Clipart