Purpose
Non-Functional requirements analysis examines the requirements for the solution that define how well the functional requirements must perform. It specifies criteria that can be used to judge he operation of the system rather than specific behaviors.
Business Analysis Body of Knowledge® (BABOK®)
Non-functional requirements are often called us the quality attributes of the system. The plan for implementing the non-functional requirements is detailed in the system architecture, because they are usually significant requirements. Functional requirements define what a system is suppose to do and non-functional requirements define how a system is supposed to be. The other terms for the non-functional requirements are called as qualities, quality goals, quality of service requirements, constraints, and technical requirements. They judge the analysis based on responsiveness, security, usability, portability, and other non-functional standards that are critical to the success of the project. It will also allow you to impose the constraints and restrictions on the design of the system across the various agile systems.
Non-functional requirements are often associated with system solutions, and they also apply more broadly to both the processes and people aspects of the solutions. They augment the functional requirements of the solution, identify the constraints on those requirements, and describe the quality attributes a solution must exhibit based on the functional requirements. Non-functional requirements are typically expressed in textual formats as declarative statements. The declarative non-functional requirements has the constraining factors with them to analyze the problem. Non-functional requirements ensure the usability and effectiveness of the entire project. It will satisfy the internal business needs, users, and the market needs which will fulfill the mandatory non-functional requirements.
Some of the articles related to Non-functional Requirements analysis techniques are as follows,
Non-functional requirements specifies how a system should perform a function, including the constraints and minimum requirements. Non-functional requirements are the quality attributes of the system which includes performance, reliability, recover-ability, security, data integrity and usability. The template for the non-functional requirement are categorized based on the performance and the areas in which the non-functional requirements are to be applied. The main elements of the non-functional requirements analysis are,
Some of the books for Non-functional Requirements analysis techniques,