7.3.4 - Example Non-Functional Requirement

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Understanding Non-Functional Requirements

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Teacher
Teacher

Today, we will explore non-functional requirements, which define how a system operates. Can anyone guess why they're as important as functional requirements?

Student 1
Student 1

I think they are important because they affect user experience.

Teacher
Teacher

Exactly! Non-functional requirements impact performance, security, and usability. We can remember these aspects with the acronym 'PURPOSE' which stands for Performance, Usability, Reliability, Security, and Efficiency.

Student 2
Student 2

So does that mean if a system is fast but not secure, it doesn't meet the requirements?

Teacher
Teacher

Correct! You need to strike a balance among these areas to satisfy user needs and project goals.

Components of Non-Functional Requirements

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Teacher
Teacher

Let’s dive into the specific components of non-functional requirements. Who can name one component?

Student 3
Student 3

Performance is one, right?

Teacher
Teacher

Yes! Performance relates to how efficiently the system operates. For instance, an NFR might state, 'The system must support 10,000 concurrent users.' Can anyone provide another example?

Student 4
Student 4

What about security requirements?

Teacher
Teacher

Great! Security is critical, too. It ensures data integrity and user confidentiality. Always remember to include both performance and security in your documentation.

Real-world Application of Example Non-Functional Requirements

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Teacher
Teacher

Let's look at how we can document a non-functional requirement. For example, can someone state what the requirement might be for system load times?

Student 1
Student 1

The application must respond within 3 seconds, right?

Teacher
Teacher

Exactly! This ensures that users have a seamless experience. Remember, specifying your NFRs clearly can prevent issues later during the performance testing phase.

Student 2
Student 2

What happens if we miss out on these requirements?

Teacher
Teacher

Missing non-functional requirements can lead to user dissatisfaction and project failure. Clear documentation is key!

Introduction & Overview

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Quick Overview

Non-functional requirements define criteria that judge the operation of a system rather than specific behaviors.

Standard

Non-functional requirements are essential for specifying how a system performs under certain conditions, encompassing aspects such as performance, security, and usability. These requirements are vital for ensuring user satisfaction and system reliability.

Detailed

Example Non-Functional Requirement

Non-functional requirements (NFRs) specify the criteria that can judge the operation of a system, rather than specific behaviors which are explained in functional requirements. These requirements outline how a system operates, addressing areas crucial for overall user experience and system performance.

Importance of Non-Functional Requirements

Non-functional requirements are important as they provide a quality framework within which a system must operate. They include specifications related to performance, security, usability, reliability, and compliance. These aspects are vital for meeting stakeholder expectations and ensuring the system's effectiveness in a real-world context.

Key Components

  • Performance: e.g., response time, throughput.
  • Security: e.g., data protection standards, authentication protocols.
  • Usability: e.g., user-friendly interfaces, accessibility features.
  • Reliability: e.g., system uptime, error rates.

Example Non-Functional Requirement

The system must support up to 10,000 concurrent users while maintaining a response time of less than 3 seconds. This example illustrates how a non-functional requirement specifies critical system capabilities that, while not tied to specific functionalities, impact overall system success and user satisfaction.

Conclusion

In summary, non-functional requirements are essential to document as they provide guidelines for system operation and performance, ensuring all stakeholders understand the quality attributes vital for the system's success.

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Definition of Non-Functional Requirement

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Example Non-Functional Requirement:

“The application shall support up to 10,000 concurrent users with response time < 3 seconds.”

Detailed Explanation

This text presents an example of a non-functional requirement, specifying performance criteria for an application. It indicates that the application should be capable of handling up to 10,000 users accessing it simultaneously, while ensuring that the response time for any user action doesn’t exceed three seconds. This requirement is crucial as it highlights the system's expected performance under load.

Examples & Analogies

Imagine a popular restaurant that can seat 10,000 diners at once, serving food quickly. If customers call in to place orders, the restaurant must ensure they don’t keep customers waiting too long (more than three seconds) to confirm their orders, regardless of how many patrons are calling at the same time.

Importance of Non-Functional Requirements

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Non-Functional Requirements include aspects like performance, security, usability, and reliability.

Detailed Explanation

Non-functional requirements describe how a system performs certain functions, as opposed to what functions it performs. They cover a range of factors including how fast the system operates (performance), how secure it is (security), how easy it is for users to navigate and use the system (usability), and how consistently it operates under various conditions (reliability). These factors are important because they directly affect user satisfaction and system effectiveness.

Examples & Analogies

Think of non-functional requirements like the layout and ambiance of a restaurant. A well-designed layout (usability) enables diners to find their seats quickly, while a comfortable atmosphere makes for a better dining experience. No matter how great the food is (the actual function), if the restaurant isn't easy to navigate or feels unsafe, customers may choose not to return.

Collaboration on Non-Functional Requirements

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BA’s Role:

● Collaborate with system architects and dev leads
● Ensure all stakeholder requirements are included
● Review and validate with technical and QA teams

Detailed Explanation

The Business Analyst (BA) plays a critical role in defining non-functional requirements. They work together with system architects—who understand the technical aspects of the system—and development leads to ascertain that the non-functional requirements align with technical capabilities. Additionally, the BA must ensure that these requirements reflect the needs and expectations of all stakeholders involved in the project and validate them with technical and quality assurance (QA) teams to confirm feasibility and accuracy.

Examples & Analogies

Consider the BA as the Event Planner in charge of organizing a large-scale event. The Event Planner works with venue coordinators (system architects) to ensure that the event space can accommodate all guests comfortably (non-functional requirement). They also consult with the catering team (developers) and safety inspectors (QA) to make sure everything meets the hosts' expectations and complies with regulations.

Definitions & Key Concepts

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Key Concepts

  • Performance: The speed and efficiency with which a system performs specified tasks.

  • Security: The measures taken to protect data from unauthorized access.

  • Usability: The ease of use and satisfaction of the user with the system.

  • Reliability: The probability that a system will perform without failure under given conditions.

Examples & Real-Life Applications

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Examples

  • Example of a non-functional requirement: 'The application should support up to 10,000 concurrent users with a response time of less than 3 seconds.'

  • Another example could be: 'The system must secure all user data via encryption protocols.'

Memory Aids

Use mnemonics, acronyms, or visual cues to help remember key information more easily.

🎵 Rhymes Time

  • Usability and security, they must rhyme, / In a system, they save us time.

📖 Fascinating Stories

  • Imagine a librarian with a shelf of books. If the librarian works fast but can't secure the rare books, the users lose trust. This story shows how performance and security are just as important.

🧠 Other Memory Gems

  • To remember key non-functional requirements, use 'PURPOSE': Performance, Usability, Reliability, Security, Efficiency.

🎯 Super Acronyms

The acronym CURE can help remember

  • Capacity (performance)
  • Usability
  • Reliability
  • Security.

Flash Cards

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Glossary of Terms

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  • Term: NonFunctional Requirement

    Definition:

    Criteria that determine the operation of a system, such as performance and security.

  • Term: Performance

    Definition:

    A measure of how quickly a system responds under given conditions, often quantified in response times or throughput.

  • Term: Security

    Definition:

    The measures and protocols to protect data and ensure user confidentiality.

  • Term: Usability

    Definition:

    The ease with which users can interact with a system, including accessibility.

  • Term: Reliability

    Definition:

    The ability of a system to function correctly under expected conditions.