Formulating Cybersecurity Requirements for Autonomous Ships Using the SQUARE Methodology.

Artificial intelligence (AI) technology is crucial for developing autonomous ships in the maritime industry. Autonomous ships, based on the collected information, recognize the environment without any human intervention and operate themselves using their own judgment. However, ship-to-land connectivity increased, owing to the real-time monitoring and remote control (for unexpected circumstances) from land; this poses a potential cyberthreat to various data collected inside and outside the ships and to the applied AI technology. For the safety of autonomous ships, cybersecurity around AI technology needs to be considered, in addition to the cybersecurity of the ship systems. By identifying various vulnerabilities and via research cases of the ship systems and AI technologies, this study presents possible cyberattack scenarios on the AI technologies applied to autonomous ships. Based on these attack scenarios, cyberthreats and cybersecurity requirements are formulated for autonomous ships by employing the security quality requirements engineering (SQUARE) methodology.

Cyberattack Models for Ship Equipment Based on the MITRE ATT&CK Framework.

Cybersecurity is important on ships that use information and communication technology. On such ships, the work, control, and sensor systems are connected for steering, navigation, and cargo management inside the hull, and a cyberattack can have physical consequences such as sinking and crashing. Research on ship cybersecurity is a new challenge, and related studies are lacking. Cyberattack models can provide better insight. With this study, we aim to introduce a cyberattack analysis method based on the MITRE ATT&CK framework so that a cyberattack model for ships can be established. In addition, we identify the characteristics of the attack phase by analyzing cases of hacking and vulnerability research for ship systems using tactics, techniques, and procedures, and suggest the minimum measures essential for defense. Using the ship cyberattack model, we aim to identify the characteristics of the systems used for ship navigation, communication, and control; provide an understanding of the threats and vulnerabilities; and suggest mitigation measures through the proposed model. We believe the results of this study could guide future research.

Synthesis of Solar-Light-Responsive ZnO/TaON Nanocomposite and Their Photocatalytic Activity.

The effects of the preparation conditions of ZnO-modified TaON on the photocatalytic activity for degradation of rhodamine B dye (Rh. B) under simulated solar light were investigated. The ZnO/TaON nanocomposite were prepared by loading particulate Ta2O5 with ZnO using different ZnO contents, followed by thermal nitridation at 1123 K for 5 h under NH3 flow (20 ml min(-1)). The as-prepared samples were characterized by XRD, UV-Vis-DRS, and SEM-EDX. The results revealed that the band gap energy absorption edge of as prepared nanocomposite samples was shifted to a longer wavelength as compared to ZnO and Ta2O5, and the 60 wt% ZnO/TaON nanocomposite exhibited the highest percentage (99.2%) of degradation of Rh. B and the highest reaction rate constant (0.0137 min(-1)) in 4 h which could be attributed to the enhanced absorption of the ZnO/TaON nanocomposite photocatalyst. Hence, these results suggest that the ZnO/TaON nanocomposite exhibits enhanced photocatalytic activity for the degradation of rhodamine B under simulated solar light irradiation in comparison to the commercial ZnO, Ta2O5, and TaON.

Synthesis of g-C3N4/NaTaO3 Hybrid Composite Photocatalysts and Their Photocatalytic Activity Under Simulated Solar Light Irradiation.

This Paper reports the photocatalytic activity of g-C3N4/NaTaO3 hybrid composite photocatalysts synthesized by ball-mill method. The g-C3N4 and NaTaO3 were individually prepared by Solid state reaction and microwave hydrothermal process, respectively. The g-C3N4/NaTaO3 composite showed the enhanced photocatalytic activity for degradation of rhodamine B dye (Rh. B) under simulated solar light irradiation. The results revealed that the band-gap energy absorption edge of hybrid composite samples was shifted to a longer wavelength as compared to NaTaO3 and the 50 wt% g-C3N4/NaTaO3 hybrid composite exhibited the highest percentage (99.6%) of degradation of Rh. B and the highest reaction rate constant (0.013 min(-1)) in 4 h which could be attributed to the enhanced absorption of the hybrid composite photocatalyst in the UV-Vis region. Hence, these results suggest that the g-C3N4/NaTaO3 hybrid composite exhibits enhanced photocatalytic activity for the degradation of rhodamine B under simulated solar light irradiation in comparison to the commercial NaTaO3.