SIA - LECTURES

• Data vs. Information:

  
  

  Data: a given or a fact; a number, a statement, or an image

  • Represents something (quantities, actions and objects) in the real world
  • Raw materials in the production of information
  • Information: data that have meaning within a context
  • Data that has been processed into a form that is meaningful to the recipient and is of real or perceived value in the current or in the prospective actions or decisions of the recipient
• Characteristics of Useful Information:

  • Relevant: information must pertain to the problem at hand
  • Complete: partial information is often worse than no information
  • Accurate: erroneous information may lead to disastrous decisions
  • Current: decisions are often based upon the latest information available
  • Economical: in a business setting, the cost of obtaining information must be considered as one cost element involved in any decision
• Types of Information System:

  • Operational-level systems: support operational managers by keeping track of elementary activities and transactions of the organization
  • Management-level systems: serve monitoring, controlling, decision-making, and administrative activities of middle managers
  • Strategic-level systems: help senior management tackle and address strategic issues and long-term trends, both in the firm and in the external environment
• System Development Life Cycle (SDLC):

  • A methodology that forms the framework for planning and controlling the creation, testing, and delivery of an information system
  • Acts as the foundation for multiple different development and delivery methodologies
  • Provides a sequence of activities for system designers and developers to follow
  • Aims to produce high-quality software that meets or exceeds customer expectations, reaches completion within times and cost estimates
• • Operational and Maintenance: resolving bugs and errors found during use
• Phases of SDLC:

  • Planning: evaluating project terms, calculating costs, creating timetables, and forming project teams
  • Define Requirements: determining what the application is supposed to do and its requirements
  • Design and Prototyping: modeling the software application and creating a basic version to demonstrate how it looks and works
  • Software Development: writing the actual program, tracking changes, and ensuring compatibility
  • Testing: critical testing before making the application available to users
  • Deployment: making the application available to users
• System Modeling:

  • Process of developing abstract models of a system, presenting different views or perspectives
  • Helps the analyst understand the functionality of the system and communicate with customers
  • Models of the existing system used during requirements engineering to clarify strengths, weaknesses, and requirements for the new system
  • Models of the new system used during requirements engineering to explain proposed requirements to stakeholders and document the system for implementation
• Types of System Modeling:

  • Functional modeling
  • Systems architecture
  • Business process modeling
  • Enterprise modeling
• System Perspective:

  • External perspective: modeling the context or environment of the system
  • Interaction perspective: modeling interactions between a system and its environment or between components of a system
  • Structural perspective: modeling the organization of a system or the structure
• System Design is the process of designing the architecture, components, and interfaces for a system so that it meets the end-user requirements
• System Design concepts are important for tech interviews at IT giants like Facebook, Amazon, Google, and Apple
• System Design phase includes Logical design and Physical design sub phases
• Steps for approaching a system design tutorial:

  • Understand the requirements
  • Identify the major components and their interactions
  • Choose appropriate technology
  • Define the interface between components
  • Design the data model
  • Consider scalability and performance
  • Test and validate the design
  • Deploy and maintain the system
• Tools and Techniques used for designing:

  • Flow Chart
  • Dataflow Diagrams
  • Data Dictionary
  • Structured English
  • Decision Table
  • Decision Tree
• UML Diagram Types:

  • Activity Diagrams: capture the dynamic behavior of the system
  • Use Case Diagrams: show interactions between a system and its environment
  • Sequence Diagrams: illustrate interactions between actors and system components
  • Class Diagrams: display object classes and associations
  • State diagrams: model how the system reacts to events
• Activity Diagram Notations:

  • Initial states
  • Final states
  • State or an Activity Box
  • Decision Box
• Sequence Diagram Notations:

  • Lifeline Notation
  • Activation Bars
  • Message Arrows
  • Comment
• Class Diagram Notations:

  • Class Name
  • Class Attributes
  • Class Operational (Methods)
• System architecture is the conceptual structure and logical organization of a computer system
• Data are raw facts, figures, numbers, characters, symbols, etc.
• Information is processed data that has been organized into meaningful units
• Information Classification :

  ⮚ Action v/s no action

  ⮚ Recurring v/s non recuring

  ⮚ Internal v/s external

  ⮚ Planning Information

  ⮚ Control Information

  ⮚ Knowledge Information
• System is a functional unit, which involves set of procedure/functions to produce certain outputs by processing data/information given as input.
• Characteristics of a Useful System:

  ⮚ A system is a whole

  ⮚ Components of a system interact

  ⮚ Systems are goal seeking

  ⮚ Systems have input/output

  ⮚ System must be controlled

  ⮚ System forms a hierarchy

  ⮚ Systems exhibit differentiation.
• Components of Information System:

  -People

  -Data

  -Procedures

  -Hardware

  -Software

  -Networks
• Classification of Information System:

  -Strategies Management

  -Tactical Management

  -Operational Management

  -Non-Management Stuff
• Types of Information System:

  -Operational-level system

  -Management-level system

  -Strategic-level System

  -TPS (Transaction Processing System)

  -MIS (Management Information system)

  -DSS (Decision Support System)

  -ESS (Executive Support System)

  -SDLC (Software Development Life Cycle)
• Phases of SDLC

  -Planning

  -Defined Requirements

  -Design & Prototyping

  -Software Development

  -Testing

  -Deployment

  -Operation & Maintenance
• Operational-level systems

         - support operational managers by keeping

           track of the elementary activities and transactions

           of the organization, such as sales, receipts, cash

           deposits, payroll, credit decisions, and the flow of

           materials in a factory.
• Management-level systems

           - serve the monitoring , controlling, decision-

              making , and administrative activities of middle

              managers. The principal question addressed by

              such systems is this; Are things working well?
• Strategic-level systems

            - help senior management tackle and address

               strategic issues  and long-term trends, both

               in the firm and in the external environment.
• Transaction Processing Systems (TPS)

          - Basic business systems that serve the operational

             level.

          - A computerized system that performs and records

             the daily routine transactions necessary to the

             conduct of the business.
• Management Information System (MIS)

         - Serve middle management.

         - Provide reports on firm’s current performance, based

           on data from TPS.

         - Provide answers to routine questions with predefined procedure for answering them.
• Decision Support Systems (DSS)

         - Serve middle management

         - Often use external information as well as information from

           TPS and MIS.

         - Processing is interactive in nature.

         - Output in form of Decision analysis.
• Executive Support System (ESS)

         - Support senior management-strategic level.

         - Address non-routine decisions requiring judgement,

           evaluation, and insight.

         - Incorporate data about external events (e.g. new tax

           laws or competitors) as well as summarized information from MIS

           and DSS.     
• Planning

  • project leaders evaluate the terms of the project. This includes calculating labor and material costs, creating a timetable with target goals, and creating the project’s teams and leadership structure.     
• Define Requirements

  ⮚ is considered part of planning to determine what the application is supposed to do and its requirements. For example, a social media application would require the ability to connect with a friend. An inventory program might require a search feature.
• Design and Prototyping

  ⮚ A phase models the way a software application will work. Some aspects of the design include:

  •Architecture

  •User Interface

  •Platforms

  •Programming

  •Communications

  •Security

  ⮚  is like one of the early versions of software in the iterative software development model. It demonstrates a basic idea of how the application looks and works.
• Software Development      

  • This is the actual writing of the program. A small project might be written by a single developer, while a large project might be broken up and worked by several teams.
• Testing

  • It’s critical to test an application before making it available to users. Much of the testing can be automated, like security testing. Other testing can only be done in a specific environment – consider creating a simulated production environment for complex deployments.