Object selection is the basis of natural user–computer interaction (NUI) in a virtual environment (VE). Among the three-dimensional object selection techniques employed in virtual reality (VR), bare hand-based finger clicking interaction and ray-casting are two convenient approaches with a high level of acceptance. This study involved 14 participants, constructed a virtual laboratory environment in VR, and compared the above two finger-based interaction techniques in terms of aspects of the task performance, including the success rate, total reaction time, operational deviation, and accuracy, at different spatial positions. The results indicated that the applicable distance range of finger clicking interaction and finger ray-casting was 0.2 to 1.4 m and over 0.4 m, respectively. Within the shared applicable distance, the finger clicking interaction achieved a shorter total reaction time and higher clicking accuracy. The performance of finger clicking interaction varied remarkably at the center and edge of the horizontal field of view, while no significant difference was found among ray-casting at various horizontal azimuths. The current findings could be directly applied to the application of bare-hand interaction in VR environments.

Electric power communication security is an important support for the development of Energy Internet, secure transmission protection of core and sensitive business data is the vital task of electric power telecommunication network. Quantum secret communication systems rely on quantum key distribution (QKD) mechanism. As the core equipment in quantum secret communication system, quantum VPN achieves data encryption and decryption with quantum key to improve the cipher security of traditional VPN, which can effectively enhance network security of communication in Energy Internet. In this paper, the working mechanism of quantum key distribution and quantum VPN (QuVPN) equipment is firstly described for the commercial quantum secret communication system based on polarization modulation. The simulation experiment structure of quantum VPN is designed, and the experimental environment is established by using the practical QKD equipment, quantum VPN and network tester. The most important performance characteristics including throughput, delay and encryption algorithm of quantum VPN are tested and statistically analyzed, and the verification of secure network transmission with quantum key is implemented. The test results can provide some technical reference for extensive application of quantum VPN in power grid production and management informatization business.

There has been a surge in interest in evaluating new forms of communication for Automated Vehicles (AVs), namely external human-machine interfaces (eHMIs). However, much of the research has focused on younger pedestrians' crossing behavior and experience while interacting with AVs and in daytime conditions with optimum visibility. Given that the AVs will interact with pedestrians of all ages, and at all times, there are still key knowledge gaps that need to be addressed. Using a cave-based pedestrian lab, this study investigated the effect of AV kinematics (i.e., deceleration, speed, time gaps) and eHMI (a Slow Pulsing Light Band) on the crossing behavior of younger adult pedestrians (18-35 years old) and older pedestrians (64-77 years old), in both daytime and nighttime virtual environments. Results showed that older pedestrians adopted a different crossing strategy than younger pedestrians. If they decided to cross in the non-deceleration trials, they compensated for their longer crossing duration by initiating their crossing earlier than younger pedestrians. However, if they decided to wait until the deceleration was more prominent, they waited longer than the younger pedestrians. Generally, pedestrians reported feeling less safe and behaved more cautiously during nighttime crossings (i.e., less likely to cross, longer crossing initiation time (CIT) when there was no eHMI). eHMI decreased CIT for both age groups but was interpreted and used differently between younger and older pedestrians. Finally, an eHMI failure trial mainly affected younger pedestrians. This knowledge should inform the design of effective communication for AVs for younger and older pedestrians.

With higher levels of Automated Vehicles (AVs) entering the traffic system in the future, it is important to investigate pedestrians’ crossing behaviour and experience while interacting with AVs, which lack a human driver. There has been a surge in interest within the last few years in evaluating new forms of communication for AVs, namely external human-machine interfaces (eHMIs). However, much of the research to date has focused on younger pedestrians, and on daytime conditions with optimum visibility. Given that the AVs will interact with pedestrians of all ages, and at all times, there are still key knowledge gaps that need to be addressed. Using the Highly Immersive Kinematic Experimental Research (HIKER) cave-based pedestrian lab, this study investigated the effect of AV kinematics (i.e., deceleration, speed, time gaps) and eHMI presence (a Slow Pulsing Light Band) on the crossing behaviour of younger (18-35 years old) and older pedestrians (64-77 years old), in both daytime and nighttime virtual environments. Results showed that older pedestrians adopted a different crossing strategy to younger pedestrians. If they decided to cross in the non-deceleration trials, they compensated for their longer crossing duration by initiating their crossing earlier than younger pedestrians. However, if they decided to wait until the deceleration was more prominent, before making a crossing decision, they waited longer than the younger pedestrians. Generally, pedestrians reported feeling less safe and behaved more cautiously during nighttime crossings (i.e., less likely to cross, longer crossing initiation time (CIT) when there was no eHMI). The lower perceived safety ratings were more prominent for older pedestrians, especially when crossing at 3-second time gaps and in the nighttime environment. eHMI decreased CIT for both age groups. However, different interpretations of eHMI were observed between younger and older pedestrians, showing that eHMI might have been used differently across age groups. Finally, an eHMI failure trial mainly affected younger pedestrians, whose collision rate increased from 0.43% in non-deceleration trials without eHMI, to 1.72% when the vehicle displayed the eHMI but did not decelerate. This study demonstrated that pedestrians are likely to behave differently during daytime and nighttime, and that older pedestrians are likely to have different requirements from AVs than younger pedestrians. This knowledge should inform the design of effective communication for AVs.