## 4 Verification of the Method
### Assessment of the Reliability of the Cargo Handling Process  
Based on the cargo handling process map (Appendix D), a structural model was drawn up, thanks to which it is possible to determine the reliability of the cargo handling process from the time the order is accepted up to the cargo being delivered to the customer. In the analyzed process of cargo handling, it can be concluded, based on the map (Appendix D), that many operations within individual activities are performed in parallel. The development of the structural model (Figure 8) is intended to facilitate further calculations. Itemization of the basic operations within the sub-processes, as well as routing of the parallel paths, will simplify the creation of a reliability model using the event tree method. On the bases of the structural model reliability may be determined using event trees. For activity \(d_{1}\), the initiating operation comes in the form of sending the order by the ship's owner, \(z_{1}\) (Figure 9). In the case of the consequent activity \(d_{2}\), the initial operation consists in sending the advice not listed. First, the \(I_{2}\) advice not listed from the port is drawn up and sent to the container terminal for the railway dispatcher (Figure 10). \[SJ_{2_{1}}=1,\ FJ_{2_{2}}=0\]  
Figure 8: Structural diagram of the cargo handling process at the container terminal. Figure 10: Event tree for activity \(d_{2}\). Figure 9: Event tree for activity \(d_{1}\). The next initiating operation is the cargo transportation by rail to the container terminal \(z_{3}\). The path in the structural model shows that within the initiating operation \(z_{3}\), 3 actions are performed in sequence (\(d_{3}\), \(d_{4}\), \(d_{5}\)): transportation of the cargo from the port to terminal \(z_{3}\) (Figure 11). Therefore, the process reliability \(R_{pr}\) is equal to:  
\[R_{pr}=SJ_{1_{1}}*SJ_{2_{1}}*SJ_{3_{1}}=1*1*0.98=0.98\]  
The reliability of the cargo handling process in the tested real-time system is \(R_{pr}\) = 0.98. In the case of the binary tree from the figure, because only the fact that a given action will be performed or not will be taken into consideration, the process of cargo handling in the engineering system under analysis is characterized by high reliability. In the case of the first two activities (\(d_{1}\) and \(d_{2}\)), there was no situation during the study of the process when the dispatchers did not perform these activities. After the (\(I_{1}\) i \(I_{2}\)) messages are received, the data are always entered into the system. In the case of the last path, the situation where the advice note list is received and the train does not arrive at the container terminal does not happen. Once, a situation arose where railway dispatchers received an advice note list; then they received information that there were disturbances at the port, and the target train, which was to arrive at the terminal, was reloaded and sent the next day. The last activities (\(d_{3}\), \(d_{4}\) and \(d_{5}\)) also confirm the high reliability of the operating process. The operator who receives the list of containers carries out the cargo translocation operation and loads the container onto the vehicle. If there are any disruptions at this point, it is mainly on-route the transportation to the customer, when the driver has a loaded vehicle, leaves the terminal and delivers the cargo to the customer. Assessment of the Reliability of the Cargo Handling Process, Considering the Timely Execution of Operations  
On the basis of the studies presented in Section 4.1, reliability could be determined, taking into consideration the timely execution of operations in individual activities. In this case, the number of operations experiencing a delay was taken into account; for each bm operation, the values were as follows:  
\[t_{b_{1}}=0.98\;\mathrm{h},\;t_{b_{2}}=0.98\;\mathrm{h},\;t_{b_{3}}=6\;\mathrm{ h},\;t_{b_{4}}=0.058\;\  
Transportation of cargo from the port to terminal \(z_{3}SH_{1_{1}}\)= 0.93, \(SFH_{1_{2}}\)= 0.07, \(FH_{1_{3}}\)= 0.