In Elastic Optical Networks (EONs) with flexible bandwidth allocation, the blocking probability is high because of spectral contention. Similar to the functionality of wavelength conversion in Wavelength-Division-Multiplexing (WDM) networks, waveband conversion has been proposed to solve spectral contention in EONs. In this paper, we discuss the design of node architectures for an EON with waveband conversion. Four node architectures with shared Tuneable Waveband Converters (TWBCs) are proposed, and their blocking performances are evaluated by simulation. Simulation results show that the blocking probability of a node is significantly improved by waveband conversion. The sharing efficiency of waveband converters is also investigated. Simulation results show that at the same blocking rate, the node architecture with converters shared per node can save more than 20% waveband converters compared with that of the one with converters shared per link.
1 May 2019 in Archives of Civil and Mechanical Engineering
In order to study the neck response of elderly drivers in rear collision, a finite element model for elderly neck was built. By comparing the cadaver experiment data in the literature, the simulation reliability of the head and neck model of the elderly under dynamic load was verified. Through the C‐NCAP rear‐end collision test on the elderly model, the study showed that the neck of the elderly driver had good dynamic response characteristics. The verified finite element model was used to analyze the head and neck collision response and injury risk of the elderly under different distances between the head and the headrest (vertical distance and horizontal distance). By analyzing the head and neck injuries of occupants at different distances, it was found that when the horizontal distance was 50 mm, and the vertical distance was between +10 and ~+20 mm, the headrest could play the best role in protecting the neck of the elderly driver and could reduce the degree of injury of the elderly driver in the process of rear collision.
13 March 2019 in Multimedia Tools and Applications
In autonomous vehicle, since that occupants no long need to operate the vehicle, they will have time to relax and entertain or communicate with other people. In order to improve the collision safety of the occupants who move freely and have different seat orientation angles in autonomous vehicle, a protection strategy based on the cooperative control of the rotating seat and belt airbag to avoid occupant injuries is proposed: in the pre-crash phase, the occupant on a rotated seat is repositioned into a close-to-standard frontal facing position, while the belt airbag deploys; in the crash phase, the fully deployed belt airbag cushions and absorbs occupant impact with the support of the occupant’s legs to reduce injury. Firstly, the current prediction time for unavoidable collisions in self-driving cars is about 350 ms, therefore, the airbag can be inflated by enlarging the inflation duration to reduce its impact during deployment. Due to the fixed installation position of the dashboard airbag, which cannot accompany the deficiency of seat movement, a new type of belt airbag is designed; Then, the simulation models of ±45° and ±90° seat orientation were established to study the injury mechanism and kinematic response of occupants with different seat orientations in frontal crashes; Finally, the simulation models of active rotating seat with belt airbag were established to study the kinematic response and injury risk of occupants with rotating seat and belt airbag protection strategy. The belt airbag with a capacity of 65 L developed in this paper could effectively protect occupants in a frontal collision at an inflation time of 200 ms and a total inflation mass of 31.4 g; The occupant safety strategy based on rotating seat and belt airbag can effectively reduce the risk of collision injury of occupants with different seat orientations in autonomous vehicle.