RESUMO
To address the issues of low efficiency and high complexity of detection models for electric power workers in distribution rooms, the electric power worker identification approach is proposed. The ArcFace loss function is used as the coordinate regression loss of the target box. According to the score, the template box with the highest score is selected for prediction, which speeds up the rate of convergence. Dimensional clustering is used to set template boxes for bounding box prediction. The experimental results show that the improved YOLOv3 is a high-performance and lightweight model. The electric power worker identification approach proposed in this paper has a high-speed recognition process, accurate recognition results. The effectiveness of the approach is verified with better detection performance and robustness.
RESUMO
To prevent vehicle crashes, studies have proposed the use of flashing signals (brake lights or other light indicators) to improve the driver's response time when the leading vehicle is braking. However, there are no consistent results on the ideal flashing frequency of the brake lights. This study aimed to investigate different brake light flashing frequencies to assess their impact on braking response time. Twenty-four participants aged 25 to 30 were recruited. Two driving speed environments (50 and 80 km/h), three deceleration rates (0.25, 0.6, and 1 g), and four brake light flashing frequencies (0, 2, 4, and 7 Hz) were examined. Braking response time, average braking force, and braking response time ratio were used to evaluate the driving behavior. The results showed that the braking response time and average braking force were affected by the deceleration rate in the 50 km/h driving environment. In the 50 and 80 km/h driving environments, although there were no significant differences among the three deceleration rates, the braking response time decreased by 3-7% under the flashing brake light condition. These findings can be used as a reference for safety designs as well as future studies on driving behavior.
RESUMO
PURPOSE: The association between occupational radiation exposure and endothelium-dependent vasodilation (EDV) remains unclear. This study evaluated the association between radiation exposure and EDV among fluoroscopy-guided interventional procedure specialists and explored the possible mechanisms. MATERIALS AND METHODS: Brachial flow-mediated dilation was compared in 21 interventional cardiologists (the radiation group) and 15 noninterventional cardiologists (the nonradiation group). Animal radiation experiments were also performed to observe the impact of radiation on EDV. RESULTS: Flow-mediated dilation in both the left (radiation group, 3.63% vs. nonradiation group, 6.77%; P < .001) and right brachial arteries (5.36% vs. 7.33%, respectively; P = .04) and serum nitric oxide (NO) level (343.69 vs. 427.09 µmol/L, respectively; P = .02) were significantly reduced in the radiation group compared to those in the nonradiation group. EDV was significantly impaired in acetylcholine concentrations of 3 × 10-6 mol/L and 10-5 mol/L (60.09% vs.74.79%, respectively; P = .03; and 62.73% vs. 80.56%, respectively; P = .002), and reactive oxygen species levels in the aorta intima and media layers were significantly increased in mice after a single x-ray exposure, which could be partly rescued by pretreatment with folic acid (P < .05). CONCLUSIONS: Radiation exposure can lead to impairment of flow-mediated vasodilation in human or EDV in mice. In mice acutely exposed to radiation, folic acid alleviated radiation-induced EDV impairment by possible reduction of reactive oxidative species.
