## 4 Discussion  
The definition of resources in the BPMN 2.0 standard is abstract. It is clearly stated in its specification that the modeling of organizational structures and resources is outside of the scope, as mentioned in Reference [15]. Despite the relevance of the studies proposed to model resource specification and resource management, they show only some aspects of how a resource is used within a workflow case. There are two types of contributions in resource simulation in BPMN. The first type of contribution enhances the expressive capabilities of BPMN in terms of human resource technical behavior (allocation, distribution... ), in order to select the best technology/WFMS to support the organizational needs, as in References [21; 35; 36]. The second type of contribution highlights the importance of considering the non-functional requirements of resources rather than only the control and data flow, since the non-functional requirements of a business model are affected by the skills and other factors of the resources assigned, as in References [22; 37; 38]. This work belongs to the second category and builds on the research of [PERSON] et al. [22]. To the best of our knowledge, their proposition is the only one that introduced the composite resource whilst respecting the BPMN extension recommendations. This work distinguished atomic and composite resource types. As described previously, each type has its own characteristics to be taken into account when computing its service time and its reliability. For example, to calculate the service time of a human resource, we should take into account their skills, experience, availability, etc. For IT resources, however, throughput and loading time are more important to take into consideration. In addition, these parameters have positive or negative impacts on the non-functional indicator. An unavailable and less skilled worker will take more time to execute a task and vice versa. This shows that taking these characteristics into account will help the right questions to be asked regarding the decisions to be made to improve a process. The goal of resource performance aggregation is to obtain a synthetic and global view of the performance efficacy situation. In general, it helps the analyst to choose the most critical process for analysis and enhancement. More specifically, within a process, it will help to quickly point out the critical path that can be improved. Furthermore, the computation of parallel, sequential, and alternative structures are very different. Thus, taking into consideration the structure of the resources that carry out a task allows for more precise and reliable measures of efficacy, and could avoid unnecessary changes being made. After carrying out an overall simulation, this work proposes the use of composite resources (worker and task form). The idea is to assign to each field of a task form the service time the user takes to fill it. This finer-granularity simulation helps to better design graphical interfaces by providing only the information needed to save time and to decrease the error rate. That is very helpful for administrative processes for which user interfaces are their main core. The non-functional indicators used in this work were limited to performance and reliability. For future work, adding a more exhaustive indicator would be interesting and might better meet the requirements. Firstly, we believe that adding cost as a non-functional indicator would be helpful and add value to decision-making in order to reach process effectiveness. Cost represents the spending required for the execution of a business process. Thus, performance, reliability, and cost are fully interrelated. The amount of time/quantity required to perform/repair tasks is directly related to the cost of resources assigned. Therefore, the analyst could have a global and complete idea of the costs of the different simulation scenarios played.