Requirements formality levels analysis and transformation of formal notations into semi-formal and informal notations

It is pivotal to have well-specified requirements to eliminate errors at an early stage of the system development life cycle. Some quality standards recommend the use of formal methods - mandate requirements to be expressed in formal notations - to detect errors. However, formal notations are not suitable for non-experts and may not be understood by all the stakeholder. To fix this, bidirectional transformations among requirement representation levels are required to maintain traceability and facilitate the communication of requirements among all the involved parties. This paper reflects on the different formality levels of requirements specifications including: informal, semi-formal, and formal notations. In addition, an automated multi-layer transformation approach is proposed to enable bi-directional transformation among requirements levels.