[ Information System ] Analysis and Design

Ch.1
Foundations for System Development

📌 Information System

1️⃣ Definition of Information

2️⃣ Key Components of Information System

• Data
• Data Flows
• Processing Logic

3️⃣ Types of Information Systems

• TPS ( Transaction Processing System )
  : Automate handling of data about business transaction.
• MIS ( Management Info System )
  : Convert raw data from TPS into meaningful form.
• DSS ( Decision Support System )
  : Provide interative environment for decision making.
• ES ( Expert System )
  : Computer programs that give answers about thought of human experts.

Why organizations
undertake information system project?

💬 To take advantages of business opportunities.
💬 To solve business problems.

4️⃣ Sources of Information Systems

• Outsourcing
  : Turning over responsibility for some or all of an organization information system’s operation to an outside firm.

Why would an organization outsource its information systems operations?

💬 To take advantages of effective cost.
💬 To overcome organizational problems in information system units.

• ERP ( Enterprise Resource Planning )
  : Software systems that help to effectively manage all parts of business processes in an integrated system.

Pros
Approach include a single repository of data for all aspects of a business process and the flexibility of the modules.

• Higher productivity: Automate business processes to help everyone in your organization do more with fewer resources.
  Deeper insights: Eliminate information silos, gain a single source of truth, and get fast answers to mission-critical business questions.
  Accelerated reporting: Fast-track business and financial reporting and easily share results. Act on insights and improve performance in real time.
  Lower risk: Maximize business visibility and control, ensure compliance with regulatory requirements, and predict and prevent risk.
  Simpler IT: By using integrated ERP applications that share a database, give everyone an easier way to work.
  Improved agility: With efficient operations and ready access to real-time data, you can quickly identify and react to new opportunities.

Cons
The systems are complex, so implementation can take a long time to complete.

• Cloud Computing
• Packaged Software
• Open-source Software
• In-house Development

5️⃣ Criteria for Choosing Off-the-Shelf Software

• Cost
• Documentation
• Ease of Installation
• Functionality
• Flexibility
• Vendor Support
• Viability of Vendor
• Response Time

📌 Environment of System Development

1️⃣ Definition of System

• System
  : A collection of components organically related to achieve object.

2️⃣ Characteristics of System

• Input/Output
• Composition
• Interfaces
• Interrelationship
• Components
• Boundary
• Environment

3️⃣ Concepts of System

• Coupling
  : The extent to which subsystems depend on each other.

• Cohesion
  : The extent to which systems or subsystems perform a single function.

• Decomposition
  : The process of breaking down a system into smaller components.

  Decomposition is a technique
  that allows the System Analyst

  💬 To break a system into manageable subsystems.
  💬 To focus on one area at a time.
  💬 To concentrate on component pertinent to one group of users.
  💬 To build different components at independent times.

• Modularity
  : The process of dividing a system up into chunks or modules of a relatively uniform size.

• System Integration
  : Allow hardware and software from different vendors to work together.

4️⃣ Roles of Systems Analyst

• The role of Systems Analyst
  : A person who analyzes and designs systems when constructing information systems.

• Skills need to Analyst
  analytical, technical, managerial, interpersonal

5️⃣ System Development Methodology

• SDLC ( System Development Life Cycle )
  : A standard process followed in organization to develop information system.

• Phases of SDLC

  🔻 Planning and Selection

  • Identification of need
  • Investigation and Determination of scope

  🔻 Analysis

  • Determine Requirement
  • Generate Alternatives
  • Compare Alternatives
  • Recommend Best Alternative

  🔻 Design

  • Logical
    : Concentrate on Business Aspects
  • Physical
    : Concentrate on Technical specifications

  🔻 Implementation and operation

  • Hardware and Software Installation
  • Programming
  • User Training
  • Documentation

6️⃣ Alternative Approaches to Development

• Prototyping
  : Building a scaled-down version of the desired information system.

• Pros
  Involve the users in analysis and design.
  Quickly convert requirements to working version of system.

• Cons
  Tendency to avoid formal documentation.
  Difficult to adapt to more general user audience.

• Useful when?
  User’s requirements are not clear.

• CASE ( Computer-Aided Software Engineering )
  : Automating software tools that used by systems analysts to develop information systems.

• JAD ( Joint Application Design )
  : To collect users, managers, and developers brought together for a series of intensive structured meetings.