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We report a case of anterior ischemic optic neuropathy associated with udenafil. A 54-year-old male presented with an acute onset visual field defect of the right eye after udenafil use. Examination revealed a relative afferent pupillary defect and a swollen disc. Automated visual fields revealed an enlarged blind spot and a narrowed visual field. Fluorescein angiography revealed both an inferior choroidal filling delay and an inferior sector filling delay of the optic disc in the arteriovenous phase as well as diffuse leakage of the optic disc in the late phase. Optical coherent tomography revealed increased thickness of the retinal nerve fiber layer, especially in the area of the inferior disc. The patient was counseled to discontinue the use of udenafil and to monitor his blood pressure regularly. The disc swelling was resolved with residual optic atrophy one month after discontinuing the use of udenafil.

-This induced voltage measurement test and electromagnetic field simulation are related to the possibility of control signal malfunction by power line. Through an experiment, this research analyzed whether the voltage causing control malfunction according to the on/off status of power permitted to power line was induced to control signal line. Also, the research calculated the voltage induced to control signal line and examined the phenomenon by conducting an electro-magnetic fieldspecific simulation through the finite element method for the cable model used in the experiment.

-Pantograph must be correctly attached to catenary to continuously supply stable power to railway vehicle, and the device used here is Auxiliary Air Compressor (ACM). The existing ACM used the DC motor that included commutator and brush. Since maintenance and repair by mechanical friction are essential for the DC motor, BLDC motor studies have been conducted to improve this. A three-phase BLDC motor does 120° two-phase commutation through hall sensors in general. However, since hall sensor is vulnerable to heat and can run only when all three sensors work normally, sensorless control method has been studied to solve this. Using back EMF Zero Crossing Point (ZCP) detection method, this paper will introduce a stable switching sensing method that has a noncommutation area in a low speed zone.