Requirement Analysis and Specifications: Computer Science YouTube Lecture Handouts

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Title: Requirement Analysis and Specifications

Requirement Analysis and Specifications: DFD, SRS | Computer Science


Requirement Analysis & Specification

  • Requirement: The aim is to gather the customer requirement information about the product or software in order to create a best product as per need.
  • Specifications: The requirements will be then systematically organized into a document. Which will be also called as specification document or SRS (Software Requirement Specification) .
  • System Analysis: The engineer or the person collects, analyses the customer՚s requirements and create the final SRS is known as System Analysis.
  • Thus, Requirement Analysis and specification is a very important and mandatory phase in the life cycle of SDLC (Software Development Life Cycle) .
  • In order to create a perfect product first of all we must be very peculiar about the requirements of the customer about the product.

Requirement Engineering Phases

Requirement Engineering Phases

Requirement Engineering Tasks

  • Inception: establish a basic understanding of the problem and the nature of the solution.
  • Elicitation: draw out the requirements from stakeholders.
  • Elaboration: create an analysis model that represents information like functional and behavioral aspects of the requirements.
  • Negotiation: It means an agree on a deliverable system that is realistic for developers and customers.
  • Specification: describes the requirements specification for errors, ambiguities, omissions and conflicts.
  • Requirement management: manage changing requirements.

Requirement Analysis Can be Done through DFD

Data Flow Diagram: It Makes Requirements Consistent

  • levels: DFD level 0 (content diagram)
    • DFD level 1 (steps)
    • DFD level 2 (detailed)

Requirement Analysis Can Also be Done through E R Diagram

(entity Relationship Diagram)

  • DFD can be further converted to DD (Data Dictionary) to define data items.
    • Example:
      • x = (a) optimal data elements a
      • x = y + x; x contains data items y and x

Requirement Can be of Two Types

Requirement Can be of Two Types
Functional requirementsNon-Functional Requirements
What a system must do and what must notIt defines constraints and system properties.
How system must respond to different inputsExample: reliability, response time & storage requirements.
Describe functionally of system services
Product featuresProduct properties
User RequirementsUser expectations

Goals of Requirements Analysis and Specification Phase

  • Fully understand the user requirements
  • Remove inconsistencies, anomalies, etc.
  • Document requirements must meet in SRS documents

Information Can be Gathered From

  • Observation of existing systems.
  • Interacting with customer and end-users
  • Analysis of what needs to be done etc.

Goals of Requirements Analysis and Specification Phase: SRS

Goal of SRS Document

To develop the product, development team starts to develop the product according to the requirements recorded in the SRS document

Properties of SRS

  • Concise
  • Easy to change
  • Consistent
  • Completeness traceable
  • Verifiable


Question: Identify the false statement?

Statement 1: Product properties are included in the functional requirements of the user.

Statement 2: DFD stands for Data Flow Diagram


(1) Statement 1

(2) Statement 2

(3) Both 1 and 2

(4) Neither 1 nor 2

Answer: 1

Question: What do you understand by the term ‘Inception’ ?


(1) draw out the requirements from stakeholders.

(2) establish a basic understanding of the problem and the nature of the solution.

(3) Creating good relation between engineer and the customer

(4) Both 1 and 2

Answer: 2

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