## 3 Research and Results
### MCDA Results
In the case of alternative A3, the final two criteria (C7 and C8) contribute significantly to the evaluation due to issues related to the vessel's registration and certification, as well as its history of inspections or accidents (purple group). For alternative A10, three criteria (C3, C4, and C8), each from a different group, are responsible for its high score. The green group reflects non-compliance with navigational regulations, the blue group indicates signaling irregularities, and the purple group relates to the vessel's official status. The rank position of A6 suggests that this alternative also should be subject to further risk-oriented analysis. Its relatively high score results from the fulfillment of a single, but highly significant, criterion--C1--which belongs to the yellow group associated with vessel movement parameters. This ship may be classified as a unit requiring further monitoring. Figure 6: Net flow ranking. The proposed method provides quick results, and the analysis is straightforward. Compared to average ships, a suspect vessel will typically appear at the top of the ranking. A more detailed analysis can reveal the individual criterion or group of criteria responsible for the final score. However, the method also has its limitations. Currently, there is no integrated access to all necessary databases. Implementing this method will require both legislative and technical solutions. On the legislative side, appropriate international agreements are needed to enable data sharing. On the technical side, IT solutions will require a seamless and attack-resistant platform capable of integrating the relevant parameters. The above analysis was carried out for a relatively large set of alternatives. In real-world maritime conditions, within such a group, most vessels will typically be positively  
Figure 8: Profiles of alternatives A3, A10, A7, and A6. Figure 7: PROMETHE rainbow. evaluated. A vessel that receives a negative evaluation will stand out clearly against the background of positively rated ships. When the set of alternatives is smaller, the analysis becomes more challenging. Figure 9a-d present the results of additional scenarios (Nos. 2, 3, 4, and 5) involving small groups of vessels. Figure 9a,b (Scenarios 2 and 3) show the results of a multi-criteria evaluation involving two pairs of vessels. This means that the analysis is based solely on a comparison between the two vessels in each pair. Two pairs of vessels with remarkably similar characteristics were selected for the study (A8 and A11, and A3 and A10). From the first scenario, it is known that the first pair is considered safe, while the second pair is classified as suspicious. If the vessels are indeed remarkably similar to each other, their net flow values will be close to zero. A small distance between them in the ranking suggests only minor differences in their evaluations. In such cases, it is not possible to determine definitively whether the vessels are safe or suspicious. We can only observe which one meets the risk criteria to a greater extent--meaning that it is considered more dangerous. However, this issue can be addressed by introducing a reference alternative into the analysis. Such a reference alternative is defined as having a desirable set of attributes--meaning that it is positively evaluated across all criteria. In this case, it is a ship that complies with traffic regulations, possesses clean records, transmits AIS signals properly, and exhibits stable maneuvering behavior. Alternative A11 serves as an example of such a reference vessel. Figure 9: PROMETHEE ranking results for Scenarios 2, 3, 4, and 5 (**a–d**, respectively). Figure 9c (Scenario 4) presents the results of an analysis of three vessels: A3, A10, and A11. Knowing that A11 is a reference alternative, vessels that deviate significantly--such as A3 and A10--will be ranked far apart.