Requirements engineering contains a set of activities for discovering, analysing, documenting, validating and maintaining a set of requirements for a system [6]. Requirements engineering is divided into two main groups of activities; namely, requirements development and requirement management. Requirement development covers activities related to discovering, analysing, documenting and validating requirements where as requirement management includes activities related to traceability and change management of requirements. Requirements verification consists of those activities that confirm that the product of a system development process meets its technical specifications. Requirements validation consists of activities that confirm that the behaviour of a developed system meets its user needs [7].