Modelling Human Factors using the Systems Modelling Language

HFIDTC/2/WP2.8.9/1Version 2/ 24th September 20088.1.2.3 SummaryThe summary information represented in Table 8-1 and Table 8-2 shows that the SysMLis broadly suitable for modelling a system from a human-centric viewpoint, whether thatbe to aid traditional HFI activities or MODAF-related Human Views. The language isextensible and could be used to model almost anything. However, the SysML must onlybe used where appropriate, i.e. to detail a system design from various perspectives.Typically, tools used for UML and SysML modelling allow the production of other datarepresentations, e.g. tables, which can also be used, again as appropriate. SysML does notprovide a process for system design; it purely provides a way of capturing andcommunicating a design and could be used in a similar way to HTA. From an HFperspective SysML will not replace activities such as workload analysis; However, inconjunction with appropriate tools it can be used to capture design iterations, e.g.showing the introduction of a new Post or increasing levels of automation, which amountto altering the allocation of Roles across a system.8.1.3 Benefits of using the SysMLGiven the limitations discussed in the previous section, why should HF professionalsinvest time in learning the SysML and using it to model the HVs when there is already asuite of techniques and deliverables available that fully meet their needs? The answers tothis question are given below:1. Because the SysML diagrams will be a useful source for the HF deliverables andthe generation of the diagrams will require much of the analysis work that the HFdeliverables themselves would require.2. Assuming that there are effective Systems Engineering, change management andHFI processes in place, and bearing in mind the limitations set out in the previoussection, the use of The SysML should have the following benefits to HFprofessionals;• Communication using a common language: It allows them to communicatebetter with Systems Engineers. HF professionals who are proficient in theSysML are likely be more effective in communicating the Human Views ofthe system design to Engineers who do not have a HF background, but whoare also proficient in the SysML• A formal basis for analysis: It allows them to understand more. It isimportant that HF professionals have a good understanding of systemarchitectures and technical design aspects, so that they may understand theconstraints and wider design issues that may impact trade-offs influencingHF aspects of the design. An ability to understand a system model that ispresented in the SysML would certainly enhance this wider understanding.• Consistency in information capture: The use of the SysML to modelsystems encourages analytical thinking and a rigorous approach todocumenting a design in all types of Engineer. The case study in section 7 of59