Early Identification, Specification and Measurement of Software Requirements Derived From Human Factors Requirements

factors requirements are typically described initially as non functional requirements at the system level, and system engineers must subsequently apportion these system requirements very carefully as either software or hardware requirements to conform to the Human factors requirements of the system. Within the ECSS standards, a number of views and concepts are provided to describe various types of candidate Human factors requirements at the system, software, and hardware levels.

This paper has introduced a standards-based framework for specifying and measuring software requirements for the functions needed to address the system’s Human factors requirements.

The main contribution of this paper is our proposed generic model of software FUR for system Human factors requirements. This generic model can be considered as a kind of reference model for the identification of system Human factors requirements, and can be used for their allocation to software functions implementing such requirements. System requirements allocated to hardware have not been addressed in this paper. Since the structure of the generic model is based on the generic model of software adopted by the COSMIC measurement standard, the necessary information for measuring their functional size is readily available, and an example has been presented of a specific instantiation of this reference model.

Specifically, the generic model of Human factors requirements presented in this paper is based on:

• The ECSS standards for the description of the NFR for system Human factors requirements ;

• The COSMIC measurement model of functional requirements.

The proposed specification and measurement model is independent of the software type and the languages i...

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...9759 [40] to achieve this level of detailed inputs of Human factors requirements up front in the project life cycle (that is, at the software requirements phase, rather than much later, at the software testing phase..

The proposed reference model for Human factors requirements presents a way to measure these FUR with COSMIC – ISO 19761, to take them into account in FSM-based software estimation models, thereby avoiding late discovery of mandatory FUR that lead to budget overruns and missed deadlines.

The measurement aspects presented in this paper have been limited to the system requirements allocated to software. It will be interesting in future work to investigate whether or not this measurement approach can be extended to all such requirements at the system level (that is, to all hardware-software-manual requirements, and not only to software requirements).