Software Engineering Chapter 4: Capturing Requirements
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Questions and Answers

What is one of the top factors that can cause a project to fail?

  • High levels of executive support
  • Excessive user involvement
  • Insufficient planning (correct)
  • Overly optimistic project timelines

    • What is the cost of fixing a problem during the coding phase compared to the requirements definition phase?

  • $20 (correct)
  • $200
  • $5
  • $10

    • What is the first step a requirements analyst should take when capturing requirements?

  • Create a prototype of the system
  • Work with the customer to elicit the requirements (correct)
  • Document the current behavior of the system
  • Validate the specifications

    • During which phase do analysts check that the specification matches customer expectations?

    <p>Validation</p> Signup and view all the answers

    What might prompt the team to revisit the customer during the requirements process?

    <p>Discovery of issues or omissions in specification</p> Signup and view all the answers

    What are the three categories that requirements might be separated into during prioritization?

    <p>Essential, Desirable, Optional</p> Signup and view all the answers

    What is the primary focus of a requirements definition document?

    <p>A listing of everything the customer wants to achieve</p> Signup and view all the answers

    Who is the intended audience for a requirements specification document?

    <p>Designers, testers, and project managers</p> Signup and view all the answers

    Which of the following is an example of an essential requirement for a billing system?

    <p>List current charges and sum them</p> Signup and view all the answers

    What is a key difference between requirements definition and requirements specification?

    <p>Definition focuses on customer wishes while specification focuses on system behavior</p> Signup and view all the answers

    What is a requirement in the context of software engineering?

    <p>An expression of desired behavior</p> Signup and view all the answers

    Which of the following best describes the relationship among entities in requirements?

    <p>An employee X is supervised by employee Y</p> Signup and view all the answers

    Why is it important to focus on customer needs when capturing requirements?

    <p>To avoid specifying how the behavior will be realized</p> Signup and view all the answers

    Which of the following is NOT part of the requirements process?

    <p>Understanding the customer's budget</p> Signup and view all the answers

    What type of system change might a customer request when eliciting requirements?

    <p>Replacing an existing system</p> Signup and view all the answers

    In the example of generating paychecks, which requirement specifies payment frequency?

    <p>Checks are to be issued every two weeks</p> Signup and view all the answers

    What aspect does modeling requirements primarily deal with?

    <p>Visualizing entities and their relationships</p> Signup and view all the answers

    How should requirements be documented for design and test teams?

    <p>In a manner that emphasizes customer needs</p> Signup and view all the answers

    What are the three core constructs of an Entity-Relationship Diagram?

    <p>Entity, relationship, attribute</p> Signup and view all the answers

    Which characteristic does NOT belong to requirements documentation?

    <p>Ambiguous</p> Signup and view all the answers

    Which notation is typically used to model the flow of data in a system?

    <p>Data-Flow Diagram</p> Signup and view all the answers

    What does a rectangle represent in a Data-Flow Diagram?

    <p>Actor</p> Signup and view all the answers

    Why are Entity-Relationship Diagrams popular in early requirements modeling?

    <p>They provide an overview of the problem</p> Signup and view all the answers

    Which characteristic ensures that requirements can be verified and checked?

    <p>Testable</p> Signup and view all the answers

    What represents a process in a Data-Flow Diagram?

    <p>Bubble</p> Signup and view all the answers

    What is depicted as an edge between two entities in an Entity-Relationship Diagram?

    <p>Relationship</p> Signup and view all the answers

    What is the final outcome of capturing software requirements?

    <p>A Software Requirements Specification (SRS) document</p> Signup and view all the answers

    Why is it important to discuss requirements with stakeholders?

    <p>Lack of agreement may lead to project failure.</p> Signup and view all the answers

    Which of the following is NOT a type of requirement?

    <p>Design requirement</p> Signup and view all the answers

    Who are considered clients in requirement stakeholder categories?

    <p>Those who fund the software development</p> Signup and view all the answers

    What method is NOT used for eliciting software requirements?

    <p>Analyzing competitive products</p> Signup and view all the answers

    What does a functional requirement describe?

    <p>Required behavior and activities of the software</p> Signup and view all the answers

    Which stakeholder is typically familiar with government requirements?

    <p>Lawyers or auditors</p> Signup and view all the answers

    Why might customers not fully understand their needs?

    <p>They may not recognize all their problems.</p> Signup and view all the answers

    Study Notes

    Software Engineering - Chapter 4: Capturing Requirements

    • Chapter 4 Objectives:
      • Elicit requirements from customers
      • Model requirements
      • Review requirements for quality
      • Document requirements for design and test teams

    The Requirement Process

    • Customer Requests:
      • New system
      • Replacing an existing system
      • Changing processes (e.g., manual to automatic)
      • Examples include paying bills
    • Requirements Definition:
      • An expression of desired behavior
      • Deals with objects, entities, states, and functions
    • Example Scenario: Building a system for generating paychecks, including issuing checks bi-weekly, direct deposit options (based on salary levels), and allowing access from multiple locations.

    The Requirement Process (Continued)

    • Focus on Customer Needs: Requirements should prioritize what the customer needs, not how the system will be implemented.
    • Key Entity Identification: Identify key entities, such as "employee."
    • Limiting Entities: Set limitations or constraints on entities, such as an employee being paid for a maximum of 40 hours per week.
    • Defining Relationships: Define relationships among entities, such as "employee X is supervised by employee Y." This impact how employee Y can authorize changes to employee X's salary.

    Why are Requirements Important?

    • Project Failure Factors: Incomplete requirements, lack of user involvement, unrealistic expectations, changing requirements/specifications, lack of planning, system no longer needed.
    • Cost of Requirements Errors: Errors in requirements definition are increasingly costly. For example: $1 error in definition phase translates to $5 in Design, $10 in coding, $20 in unit tests, and up to $200 after delivery.

    Process for Capturing Requirements

    • Analyst Role: Requirement analyst or system analyst performs the tasks.
    • Elicitation Process: Communicate with customers to understand requirements, asking questions, examining existing systems, and creating models/prototypes.
    • Modeling/Prototyping: Capturing requirements in models or prototypes for better comprehension.
    • Specification Phase: Define specific aspects of the required behavior, which systems must implement.
    • Validation: Verify that the specification meets customer expectations.
    • Revision: Analysis and validation may reveal problems or omissions, necessitating revision of models and specifications accordingly.

    Process for Capturing Requirements (Summary)

    • Software Requirements Specification (SRS): The final deliverable, used to communicate requirements among developers, designers, testers, and maintainers.
    • Stages: Elicitation, Analysis, Specification, and Validation.

    Requirements Elicitation

    • Customer Understanding: Customers may not fully understand their needs or problems.
    • Stakeholder Collaboration: Discussion among all stakeholders involved in the system is critical to establish agreement on requirements. This consensus is crucial, as disagreements can cripple project success.

    Requirement Stakeholders

    • Clients: Pay for the software development
    • Customers: Buy the software
    • Users: Use the software
    • Domain experts: Possess in-depth knowledge of the problem domain
    • Market Researchers: Understand market trends and potential customers
    • Lawyers/Auditors: Address legal or safety aspects
    • Software Engineers: Provide technical insights

    Means of Eliciting Requirements

    • Stakeholder Interviews: Gather information directly
    • Review Existing Documentation: Leverage available materials
    • Observe Current Systems: Learn from existing processes and procedures
    • Apprenticing with Users: Gain practical insight to understand real-world task requirements.
    • Group Interviews/Brainstorming: Encourage diverse ideas and perspectives.

    Means of Eliciting Requirements (Continued)

    • Use of Templates/Models: Models and templates help structure the elicitation process.

    Types of Requirements

    • Functional Requirements: Describe the system's required behaviors in terms of its activities and how entities change.
    • Quality Requirements: Describe the qualities the system must have (e.g., fast response time, ease of use, high reliability).
    • Design Constraints: Address architectural or design choices (e.g., platform selection).

    Resolving Conflicts

    • Multiple Stakeholder Needs: Different stakeholders may have differing requirements.
    • Prioritization: Critical requirements are categorized as "essential," "desirable," or "optional."
    • Example: A credit billing system might have essential, desirable, and optional requirements. Essential might be the ability to list charges, desirable might be separating by purchase type, and optional might be printing credits in black and debits in red.

    Kinds of Requirements Documents

    • Requirements Definition: Comprehensive list of everything the customer needs. Focuses on the current system and environment.
    • Requirements Specification: Restates requirements from the perspective of the system itself; the specifications will focus on the interface between the system and its environment. This is the technical specification intended for software developers or engineers.

    Characteristics of Requirements

    • Characteristics of High-Quality Requirements: Requirements are correct, consistent, unambiguous, complete, feasible, relevant, testable, and traceable.

    Modeling Notations

    • Standard Notations: Using standard modeling notations facilitates communication and collaboration in software development.
    • Modeling examples: Entity-Relationship diagrams, and Data-Flow diagrams.

    Entity Relationship Diagrams (ER Diagrams)

    • Core Constructs: Entities, attributes, and relationships.
    • Representation: Entities as rectangles, relationships as lines connecting entities, and attributes as annotations on entities.
    • Usefulness: ER diagrams help understand and model problem domains, showing the relationships between entities.

    Entity-Relationship Diagrams (Continued)

    • Turnstile Example: An example ER diagram to illustrate the concept using a turnstile system, with entities for visitors, coin values, and coin slots.

    Data-Flow Diagrams (DFDs)

    • Functionality Representation: DFDs show the flow of data between different system components.
    • Components: Processes (represented by bubbles), data stores, actors, and data flows (represented by arrows).
    • Example: A high-level data-flow diagram for a library system, showing interactions between customers, accounting, inventory, and other related parts of the system.

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    Related Documents

    Software Engineering: Capturing Requirements Lecture Notes PDF

    Description

    Dive deep into Chapter 4 of Software Engineering, focusing on the essential processes for capturing requirements. Learn how to elicit, model, and document requirements to ensure they meet customer needs. This chapter emphasizes the importance of understanding user requests and accurately defining the desired behavior of systems.

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