CHAPTER 1
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DFC40163
SYSTEM ANALYSIS & DESIGN
TOPIC 1 INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN
Components of System Development:
Analysis
Design
Operation and Support
Planning
Implementation
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1.1 INFORMATION SYSTEM
Definition and Importance of Information Systems
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Information
Definition: Data that has been transformed into a useful form of output.
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Information System Overview
Purpose:
Handles daily business transactions.
Improves company productivity.
Aids managers in making informed decisions.
IT Department Role:
Includes systems analysts responsible for planning, developing, and maintaining information systems.
Components:
An information system integrates information technology, people, and data to support business requirements.
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Information System Components
Major Components of an Information System:
Hardware
People
Software
Data
Processes
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a) Hardware
Definition: Physical components of the information system.
Examples:
Servers
Workstations
Networks
Telecommunications equipment
Fiber-optic cables
Mobile devices
Scanners
Digital capture devices
Other technology-based infrastructure
Hardware includes input, output, and storage devices, as well as data communication equipment.
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b) Software
Definition: Programs that control hardware and produce desired information/results.
Types:
System Software:
Manages hardware components.
Examples: Operating system, security software, device drivers.
Application Software:
Supports daily business functions and provides necessary information to users.
Examples: Enterprise applications like order processing systems, payroll systems, and communication networks.
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c) Data
Context: In a typical payroll system, data is stored in separate tables that join together to form a database.
Definition: Data is the raw material transformed by the information system into useful information.
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d) Processes
Definition: Describes the tasks and business functions performed by users, managers, and IT staff to achieve specific results.
Importance: Analysts must understand and document business processes carefully for successful system development.
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e) People
Definition: Individuals with an interest in an information system; termed stakeholders.
Stakeholder Groups:
Management group responsible for the system.
Users (end users) inside and outside the company engaging with the system.
IT staff, including systems analysts, programmers, and network administrators who develop and support the system.
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Types of Information System
Categories of Information Systems:
Enterprise Computing System
Transaction Processing System
Business Support System
Knowledge Management System
User Productivity System
Information System Integration
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Types of Information System Details
Enterprise Computing System:
Supports company-wide operations and data management requirements.
Transaction Processing System (TP):
Processes data from daily business operations.
Examples: Customer order processing, accounts receivable, warranty claim processing.
Business Support System:
Analyzes transactional data to generate information for managing and controlling business processes.
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Types of Information System Details Continued
Knowledge Management System:
Expert systems simulating human reasoning using a knowledge base and inference rules.
User Productivity System:
Provides technology to enhance employee productivity.
Examples: Email, voice mail, fax, video conferencing, word processing, and high-speed internet access.
Information System Integration:
Combines elements of TP, business support, KM, and user productivity systems within large organizations.
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1.2 SYSTEM DEVELOPMENT APPROACH
Context of information systems…
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System Development Method
Various methods exist for system development:
Structured Analysis (traditional method)
Object-Oriented (O-O) Analysis
Agile Methods (adaptive)
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Structured Analysis
Description:
Represents systems in terms of data and processes.
Organized into phases, including deliverables and milestones.
Object-Oriented Analysis
Description:
Views systems in terms of objects combining data and processes.
Agile/Adaptive Method
Description:
Stresses team-based effort, with development broken down into cycles or iterations.
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Modeling Tools for Each Method
Structured Analysis:
Data Flow Diagrams (DFDs) and process descriptions.
Object-Oriented Analysis:
Various object-oriented diagrams depicting system actors, methods, and messages.
Agile/Adaptive Method:
Tools enhancing communication (collaborative software, brainstorming, whiteboards).
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Pros and Cons of Each Method
Structured Analysis Pros:
Popular over time, relies on documentation.
Object-Oriented Pros:
Modular, reusable code, integrates well with object-oriented programming.
Agile Pros:
Flexible, efficient in handling changes, team interaction.
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Cons of Each Method
Structured Analysis Cons:
Costly changes in later phases, requirement changes can affect development.
Object-Oriented Cons:
Complexity with object interaction in larger systems.
Agile Cons:
Less structure can introduce risk, project might be subject to scope changes.
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What is SDLC
Definition of Software Development Life Cycle (SDLC):
A process for software project management within an organization.
Includes plans for developing, maintaining, and enhancing software.
Aims at improving quality of software and overall development process.
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SYSTEM DEVELOPMENT LIFE CYCLE (SDLC)
Phases
Activities:
Planning
Analysis
Design
Implementation
Testing
Maintenance
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Purpose of Each SDLC Phase
Planning:
Identify the nature and scope of business opportunities/problems.
Initiated by the system request and includes a feasibility study.
Deliverable: Preliminary Investigation Report.
Analysis:
Build logical model of the new system, fact-finding using various techniques.
Deliverable: System requirements document.
Design:
Create a physical model satisfying documented requirements, avoid misunderstandings through user involvement.
Deliverable: System design specification.
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Implementation Phase
Objective: Deliver functioning and documented information system.
Activities: Data conversion, user training, system transition.
Coding begins and includes unit, integration, system, and acceptance testing.
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Maintenance Phase
Role of Maintenance: Correct errors and meet new requirements.
Enhancements: Increase system capabilities through scalable design.
Deliverables: Operational information system.
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Group Activities
Discuss and describe various lifecycle models:
Waterfall Model
Spiral Model
Agile Model
Prototyping Model
Iterative and Incremental Development
Rapid Application Development (RAD)
Joint Application Development (JAD)
Extreme Programming
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Waterfall Model
Definition: A linear-sequential life cycle model.
Characteristics: Each phase must be completed before starting the next, no phase overlap.
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Waterfall Model Characteristics
Phases appear as a cascade, flowing downward through the project lifecycle.
Next phases begin only after previous milestones are met and signed off.
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Spiral Model
Combines iterative development with the backward-looking characteristics of the waterfall model.
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Spiral Model Description
Emphasizes risk analysis, allowing for incremental releases for refinement through iterations.
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Iterative and Incremental Development
Overview: Starts with simple implementation; enhances versions upon iteration until the complete system is developed.
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Iterative and Incremental Model Process
Whole requirements divided into sequential builds.
Each release adds functionality to the previous version, iteratively improving the system.
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Agile Model
Definition: A combination of iterative and incremental models focusing on adaptability and customer satisfaction.
Characteristics: Rapid delivery of working software in short build cycles.
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Agile Model Details
Breaks product into small builds over iterations lasting from one to three weeks.
Involved areas: planning, requirements analysis, design, coding, unit testing, and acceptance testing occur simultaneously.
Working product is showcased to customers/stakeholders at each iteration's end.
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Agile Model Advantages
Flexible and efficient in change management.
Promotes team interaction and community-based values.
Frequent deliverables validate the project's progress and reduce risks.
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Agile Model Disadvantages
Team members require high technical and communication skills.
Lack of structure/documentation poses risks.
Potential for significant scope changes as requirements evolve during development.
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Prototyping Model
Definition: Develops software prototypes to display product functionality, though may not reflect the final application's logic.
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Prototyping Model Details
Prototype is a working model demonstrating limited functionality.
Aids users in evaluating proposals and enables understanding of specific requirements before deployment.
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Rapid Application Development (RAD)
Definition: A team-based technique speeding up IS development yielding functional Systems quickly.
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RAD Details
Aims to reduce costs and development time while increasing success chances.
Emphasizes prototyping and user involvement, allowing early examination of working models for feedback.
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RAD Advantages and Disadvantages
Advantages: Quick system development, significant cost savings.
Disadvantages: Focuses on system mechanics over strategic business needs, risk of incongruence with corporate long-term objectives, less time for quality development due to tight timelines.
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Joint Application Development (JAD)
Definition: Elicitation process involving system owners and end users in collaborative workshops for application design and development.
Benefits: Shorter lifecycles, greater client satisfaction through collaborative design sessions.
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JAD Team Collaboration
Meets over days/weeks at arranged locations; applicable to business systems as well as shrink-wrap and systems software.
Reduces timing costs by improving requirement gathering and minimizing downstream changes.
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JAD Advantages and Disadvantages
Advantages: More accurate system requirements, better goal understanding, higher commitment to system success.
Disadvantages: Can be costly and cumbersome for large groups relative to project size.
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Systems Development Guidelines
Develop an overall project plan and adhere to it through logical task sequences.
Establish clear ground rules understood by all team members.
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User Involvement
Ensure user participation in development, especially for requirement modeling.
Listen closely during user interactions.
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Project Management Tools
Aim to keep projects on track and avoid surprises through reasonable checkpoints.
Managers need clarity on development costs, operation value, benefits.
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1.3 PROJECT MANAGEMENT
System Management Overview…
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Project Management Definition
Definition: Discipline of planning, organizing, and managing resources to achieve specific project goals.
Involves planning, scheduling, monitoring, and reporting on system development.
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Project Planning
Includes identifying tasks and estimating completion times and costs of each.
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Project Scheduling
Creation of timetables, showing tasks, dependencies, and critical tasks.
Staffing project teams with assigned tasks; uses Gantt/PERT/CPM charts.
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Project Monitoring
Involves guiding, supervising, and coordinating workloads.
Critical for monitoring progress and implementing corrective actions when necessary.
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Project Reporting
Regular progress reports to management, users, and project teams.
Strong communication skills are essential for effective reporting.
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Project Management Steps
STEP 1: Create work breakdown structure
STEP 2: Identify task patterns
STEP 3: Calculate critical path
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Creating Work Breakdown Structure
Definition: Breakdown of the project into smaller tasks that must be arranged logically.
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Task Patterns
Arranging tasks logically involves recognizing dependency among tasks in the project.
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Task Patterns Complexities
Dependent tasks, multiple successor tasks, and multiple predecessor tasks require careful organization.
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Types of Main Task Patterns
Dependent Tasks: Tasks that must be completed sequentially (e.g., Task 2 starts after Task 1).
Multiple Successor Tasks: Several tasks can begin simultaneously once a task is completed.
Multiple Predecessor Tasks: Tasks require multiple preceding tasks to complete before starting.
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Example of Dependent Task
Task 1: Prepare Outline Start: Day 1, Finish: Day 5, Duration: 5.
Task 2: Create Document Start: Day 6, Finish: Day 14, Duration: 9.
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Example of Multiple Successor Tasks
Task 1: Arrange Interviews Start: Day 1, Finish: Day 30, ID: 1, Duration: 30.
Task 2: Develop Plan Start: Day 31, Finish: Day 60, ID: 2, Duration: 30.
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Example of Multiple Predecessor Tasks
Task 1: Obtain Authorization Start: Day 1, Finish: Day 15, ID: 1, Duration: 15.
Task 2: Conduct Interviews Start: Day 1, Finish: Day 5, ID: 2, Duration: 5.
Task 3: Create Job Description Start: Day 16, Finish: Day 45, ID: 3, Duration: 30.
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Critical Path Analysis
Definition: A critical path consists of tasks whose delays would impact project completion.
Importance: Awareness allows project managers to keep timelines on track.
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Work Breakdown Structures and Chart Types
Understand key chart types in project management:
Gantt Charts
PERT/CPM Charts
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Gantt Chart Overview
Definition: A horizontal bar chart representing tasks.
Function: Simplifies complex projects by grouping activities.
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Gantt Chart Details
Bars show planned start and end times; lengths indicate duration.
Timeline on horizontal axis can display elapsed time or specific calendar dates.
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PERT/CPM Chart Overview
Definition: Bottom-up technique analyzing individual tasks within a complex project.
Steps: Identify tasks, estimate durations, and determine the logical order of execution.
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PERT/CPM Chart Example
Illustrates task durations, starting and finishing times, and the overall project critical path.
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Comparative Visuals
Gantt chart vs. PERT chart showing tasks, durations, and critical path in project management.
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Identifying Tasks in WBS
Explanation of listing tasks and estimating durations in a work breakdown structure.
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Task Definition
Definition of a task as a work item with a clear beginning and end requiring resources.
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Event Definition
Definition of an event (milestone): A recognizable reference point for monitoring progress.
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Task Listing Examples
First Version: Sequential listing of tasks with execution order.
Second Version: Task sequence retains chronological structure.
Third Version: Bulleted list enhances task clarity.
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Numbering and Tabular Task Listings
Presentation of tasks in a structured table format, detailing duration and predecessors.
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Gantt Chart Presentation
Gantt chart example showcasing task durations across the timeline.
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Estimating Task Duration
Task durations measured in hours, days, or weeks using weighted formulas for accuracy.
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Factors Affecting Durations
Includes project size, human resources, experience with prior projects, and existing constraints.
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Task Summary Example
Step-by-step breakdown of task durations leading to project completion.
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Using Project Management Software
Instructions for utilizing software like Microsoft Project to streamline task identification, durations, and patterns for Gantt chart creation.
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Utilizing PERT/CPM Charts
Explanation of task durations, starting, and finish timelines via project management software for effective planning.
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Project Management Software
Overview of software options:
Microsoft Project: Leading the market with comprehensive features.
Open Workbench: Free, open-source option with community support.
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Software Comparisons
Open Workbench supports XML file exchanges with Microsoft Project, providing effective project management solutions.
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Leadership and Project Management
Overview of roles in project management, particularly during large-scale projects.
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Project Management Activities
Cycle through four primary functions:
Project Planning
Project Scheduling
Project Monitoring
Project Reporting
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Project Coordination
Additional roles within project teams, such as project coordinators managing administrative responsibilities and conflicting requirements.