Incorporating non-functional requirements with UML models

The way requirements should drive the rest of the software development process has been a subject of many research projects in the past. Customers are demanding quality software which can only be achieved by considering Non-Functional Requirements (NFR) as early as possible. Since errors due to NFRs are the most expensive and difficult to correct, improperly dealing with NFRs can lead to more expensive software and a longer time to the market. If the NFRs are not considered at the early stage of the software development process, it may be difficult and expensive to address them in final product.; Despite this, a common industrial practice is to specify only Functional Requirements at the design phase and the NFRs at the implementation phase. As a result, the design of a software system may not reflect the NFRs properly and may lead to a failed product.; This research work tries to fill this gap in software development by proposing a unified modeling framework that addresses both Functional and Non-Functional Requirements. The proposed framework aims at incorporating the NFRs into the conceptual models. This integration can be used in the early stages of software development with ongoing projects or to enhance even legacy systems with NFRs. We rely on the NFR Framework to propose a solution, while defining a High Level Language for mapping that solution to the corresponding UML (Unified Modeling Language) diagrams. The proposed approach uses standard XMI representation of UML models without proposing any extension to it. We validate our approach by performing two case studies.