Different approaches for dynamic requirement engineering process models: Cone and Hour glass model

Requirements Engineering (RE)^[1] refers to the process of formulating, documenting and maintaining software requirements^[2] and to the subfield of software engineering concerned with this process. In requirement engineering phase we can gather the requirements from user and use this requirement for software development and produce software products that satisfy the user needs. Various models such as the waterfall model exist and they assume requirements engineering through the lifetime of a system. Even though requirements engineering has a fairly narrow goal - to determine a need and define the external behavior of a solution.^[7] This paper presents various approaches to the software requirement engineering models. The different models are CONE model, W model and the HOURGLASS model.