A Multi-layered Desires Based Framework to Detect Users' Evolving Non-functional Requirements

Non-functional requirements (NFRs) play a crucial role in all the downstream activities of a software life-cycle process. Capturing newly emerged NFRs is key to software evolution. Recent research shows functional requirements in the form of task-level alternative features can be elicited from user behavioral and system contextual data through user goal inference. Considering the close connection between the concept of goal and desire, we posit that there is an opportunity to extract new NFRs based on users' mental states, particularly their desires. We propose to use a statistical model to infer desires with multiple-levels of abstraction based on contextual data under Situ framework. Our multi-layered desire inference method takes inference confidence into consideration, and tries to make sense of inference results with both high-and low-inference confidence. By utilizing the different abstraction levels of desires, we provide an illustrative example with three cases to elicit users' new NFRs including new high-level and low-level desires and new contributing relationships between them. Several implications of this work are also discussed. We plan to conduct experiments on human subjects to validate the proposed method as IRB has just approved our proposal.

I. Introduction

As the early-phase of software requirements, Non-Functional Requirements (NFRs) elicitation is a crucial part of the software system requirements process. Approximately 50-60% of the errors in software development are caused by incorrect requirements, which increases the cost of fixing errors up to 100 times more in the later phases of the software development process [23]. NFRs emphasize on how to analyze and address stakeholder's interests from a series of system design alternatives [35]. A good understanding and analysis of NFRs can help make better design decisions [39], requirements changes [16], testing plans, and architectural evolution [27], [28] etc. New NFRs should be promptly discovered and properly addressed in the evolution process of a software product [35].