## 4 Discussion  
The problem statement defined in Section 1 is the following: Current manufacturing process management techniques and technologies are not well equipped for the flexibility needed in Industry 4.0. It is proposed that BPM knowledge can be applied to alleviate the stated problem. The HORSE System is positioned as a reference architecture for a manufacturing operations management system for smart manufacturing. The reference architecture complements a BPMS with several new technologies, including collaborative robotics, augmented reality and situational safety awareness. A prototype of the HORSE System is used to demonstrate the exaptation of BPM in smart manufacturing, by performing the following activities:  
* Modelling of manufacturing processes by using a standardised business process modelling notation;
* Enacting manufacturing processes populated by humans, robots, other smart devices, and conventional machines;
* Selection and assignment of agents for tasks, based on task requirements, agent capabilities, agent availability, and process status;
* Monitoring of process status and performance based on information provided by all agents. A HORSE system prototype was deployed for practical demonstration at ten factories across Europe. The prototype was deployed and demonstrated in real manufacturing facilities lending credence to the maturity of the HORSE System architecture. The factories were not only hosts, but also collaborators [82], with an active contribution to the success of the HORSE System. With ten successful demonstrations completed, the project team considers the HORSE System at technology readiness level 6 [56; 57]. The expectation is that software vendors should leverage the principles and knowledge established in the HORSE Project to envisage new manufacturing operations management tools and techniques. The demonstrations show that BPM techniques and technologies can be used to design and execute smart manufacturing processes. Beyond the viability of process management in manufacturing, the realized system yielded other benefits in the test cases. The system supports integration between levels 2, 3 and 4, which can be thought of as vertical integration. Furthermore, the system also enhances integration between various instantiations of level 2, i.e., horizontal integration. The process management system of the HORSE Project is connected to level 2 systems based on different technology, including ROS and KUKA Sunrise. Coupled with direct interfaces to humans, the system can enact cross-functional processes by orchestrating the activities of any agent in an enterprise. More interestingly, it is easier to allocate agents from one business unit to assist elsewhere. For example, if an automated vehicle fails to transport items from the warehouse, the receiving operator can be directly informed of the problem and instructed to fetch the items. Previously, the vehicle would be controlled by the warehouse management system while the operator receives instructions from the manufacturing execution system. To summarise, the demonstrations showed the following potential benefits:  
* Cross-functional process integration across business management and manufacturing operations;
* Vertical integration from business processes to individual human and automated agents;
* Improved process flexibility from run-time allocation of agents to tasks based on task requirements, agent capabilities and process status information. Regarding the notation used in this research, BPMN represents a trade-off. Indeed, [PERSON] et al. [23] compared BPMN2.0 with VSM and IDEF3 in terms of the modelling of activity sequences, timing constraints, resource assignment, material flow and information flow. The study found that BPMN2.0 is comparable to IDEF3, with the addition of process participants, event handlers and message flow; however, BPMN2.0 lacks the ability to model the physical aspects of a manufacturing system.