Modelling Human Factors using the Systems Modelling Language

HFIDTC/2/WP2.8.9/1Version 2/ 24th September 20087 Case StudyThis section takes a hypothetical system and models it from a Human Factors perspectiveusing the SysML.It is important to note that this case study is presented to illustrate how the system mightbe modelled over time, starting in the early stages of the project when the model will beat a high level, and adding detail as more information is gathered and design decisionsmade. The HVs of MODAF explained in section 6.2 will be referred to as the model isconstructed, to check that value is being added and that the HVs are being addressed. Inthis way we hope to test the utility of the SysML. This approach was taken because wefelt it was closer to real life, where at any point in time the modelling activity will addressmultiple aspects of the design and aspects of several HVs (and other views) are likely tobe addressed in a single SysML diagram. The alternative approach was to set out tomodel each HV as a package, but it was felt that this was inappropriate because the HVswere immature at the time we were starting to model and there is considerable overlapbetween them. Also it was felt that this approach is unlikely to be taken in practice,because as argued above the modelling activity will address multiple aspects of thesystem design at any point in time. However, this raises an issue, which is considered insection 8; to get a coherent appreciation of a particular HV, a reader of the model willhave to be provided with some kind of index providing a route through the model thatpulls together all the separate diagrams relevant to that view.As SysML diagrams are presented in the sections below an explanation will be providedso that they are understandable. Readers who want more details of the language itself arereferred to the SysML Website, http://www.sysml.org/13