• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.505-506
• /
• 2006

PD(partial discharge) occurred from variable PD sources in air may be the cause of breakdown in high voltage equipment which affect huge outage in power system. Identification and localization of PD sources is very important for engineer to cope with huge accident beforhand. PD phenomena can be detected by acoustic emission sensor or electromagnetic sensor like antenna. This paper has investigated the identification method using PCA(principal component analysis) for the PD signals from variable PD sources, for which the electric field distribution and PD inception voltages were simulated by using commercial FEM program. PD signals was detected by ultra wideband antenna. Their own features were extracted as the frequency coefficients transformed with FFT(fast fourier transform) and used to obtain independent pincipal components of each PD signals.

• Journal of Korean Neurosurgical Society
• /
• v.65 no.2
• /
• pp.173-179
• /
• 2022

Disabilities can emerge due to traumatic spinal fractures. In terms of sacrococcygeal spine, because of its unique anatomic structure with minimal movement, the possibility for it to have a disability is relatively low. In Korea, unlike most disability criteria, private insurance companies acknowledge angular deformities caused by vertebral fractures as disabilities according to their degree, so there were several cases where patients required compensation, arguing angular deformity caused by sacrococcygeal fracture, which in some cases led to legal conflicts. Except the Act Welfare of Persons with Disabilities which recognizes only severe angular deformity affecting internal organs as disability and the industrial accident disability evaluation which does not recognize coccygeal fracture as disability but rarely recognizes sacral vertebra deformity equivalent to compressive deformation, there is little or no case where angular deformity is recognized as disability. Given the impairment evaluation standards in social insurance, McBride system, American Medical Association (AMA) guides, and newly proposed standards by the Korean Academy of Medical Sciences (KAMS), the most contentious point in the general terms and conditions of private insurance is spinal deformity. To overcome controversy over disability evaluation, the private insurance sector is now applying criteria for axial skeleton to sacrococcygeal vertebrae through revision of standards. Under these circumstances, it is fair to recognize sacrococcygeal fracture as impairment in terms of the pelvis only when the fracture leaves serious deformity and neurological symptoms with clear relevancy. Though it may not be easy to develop accurate disability evaluation standards, improvement is necessary to remove any irrationalities and make the standards as objective as possible.

• New & Renewable Energy
• /
• v.7 no.4
• /
• pp.37-41
• /
• 2011

This paper presents a Combined solar-wave Power Generation (CPG) concept that the CPG unit is maintained as buoyant at the level of sea water and it is also supported by a submerged tunnel, with the aim of supplying emergency electric power during the station blackout events of nuclear power plants. The CPG concept has been motivated from the 2011 Fukushima-Daiichi Accidents due to the loss of both offsite AC power and emergency diesel power caused by natural hazards such as earthquake and tsunami. The CPG is conceptualized by applying different types and different sites for emergency power generation, in order to reduce common cause failures of emergency power suppliers due to natural hazards. Thus, the CPG can provide a new mean for supplying emergency electric power during station blackout events of nuclear power plants. For this application, the CPG requirements are described with a typical configuration at the ocean side of a submerged tunnel.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.3
• /
• pp.376-382
• /
• 2014

E-Actuator is an essential part of an eVGT, it receives the command from the main ECU and controls the vane. An e-Actuator failure can cause an abrupt change in engine output and it may induce an accident. Therefore, it is required to detect anomalies in the e-Actuator in real time to prevent accidents. In this paper, an e-Actuator fault detection method using on-line parameter identification is proposed. To implement on-line fault detection algorithm, many constraints are considered. The test input and sampling rate are selected considering the constraints. And new recursive system identification algorithm is proposed which reduces the memory and MCU power dramatically. The relationship between the identified parameters and real elements such as gears, spring and motor are derived. The fault detection method using the relationship is proposed. The experiments with the real broken gears show the effectiveness of the proposed algorithm. It is expected that the real time fault detection is possible and it can improve the safety of eVGT system.

• Journal of Fisheries and Marine Sciences Education
• /
• v.27 no.1
• /
• pp.49-62
• /
• 2015

As methods reducing damages by jellyfish which enter the coastal areas of Korea, attaching cutting devices to towing nets of otter trawls or pair trawls and/or using a canvas type of cutting nets of small fishing boats have been widely utilized. In order to reduce shut-down damages of power plants in coastal areas due to the mass influx of marine organisms including jellyfish, a possible improvement of the traveling water screen system and various jellyfish influx blocking devices were suggested in this study. The results could be utilized as an important index for reducing damages by jellyfish bloom which cause on a massive scale in summer in Korea.

• Journal of Convergence for Information Technology
• /
• v.9 no.5
• /
• pp.21-26
• /
• 2019

Various pipes are buried in the city as needed, such as water pipes, gas pipes and hydrogen pipes. As the time passes, buried pipes becomes aged due to crack, etc. these pipes has the risk of accidents such as explosion and leakage. To prevent the risks, many pipes are repaired or replaced, but the location of the pipes can also be changed. Failure to identify the location of the altered pipe may cause an accident by touching the pipe. In this paper, we propose a method to detect buried pipes by gathering the GPR images by using GPR and Learning with Faster R-CNN. Then experiments was carried out by raw data sets and data sets augmentation applied to increase the amount of images.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.16 no.1
• /
• pp.135-144
• /
• 2021

In railway systems, it is common to obtain train location information through an infrastructure-based train detection system. However, this system has a problem that may provide incorrect location information due to non-detection and erroneous detection, which may cause an accident. Therefore, in this study, we propose a method of providing train location information using a sensor-based integrated navigation system. In order to provide accurate information; however, the reliability of the integrated navigation system must be verified. Therefore, in this paper, we develop a simulator that can generate a reference trajectory and sensor data based on the real trajectory and analyze the performance of the integrated navigation system according to various scenarios on the real trajectory.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.12 no.4
• /
• pp.264-272
• /
• 2009

Due to an oil spill accident occurred in Taean coastal zone wide range of coastal waters were polluted. Inaccurate prediction of spilled oil trajectory is known as a cause that has increased the pollution damage in the beginning stage. In this study, a numerical modeling of spilled oil dispersion has been conducted to know which physical factors caused the severe and wide pollution. Especially the simulation is focused on how to model hydrodynamic circulation accurately. The simulation results showed that the hydrodynamic flow is very important in predicting oil fate, specially, in the short-term dispersion of spilled oil.

• Journal of the Korean Institute of Gas
• /
• v.11 no.1 s.34
• /
• pp.18-22
• /
• 2007

The fault current through the earth originated from a power line ground fault might cause arcing through the soil to an adjacent pipeline, which might bring about not only a catastrophic accident such as gas explosion and oil leakage but also a hazard to the safety of workers responsible for the maintenance and repair of the pipeline. In this paper we investigated the arcing phenomena through soil between a power line tower and a pipeline and outlined the standards for the separation distance of a buried pipeline adjacent to the power line tower.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.19 no.2
• /
• pp.92-97
• /
• 2011

Vehicle lightings are very important for safe driving during night time. Since the eye recovery time after an exposure to oncoming headlights would take after several seconds, the aiming point of vehicle head lamps have to pass safety requirements. Despite the fact that vehicle inclination is variable with vehicle load conditions, the head lamps aiming point is usually fixed at a constant position which is set by car manufacturer. Consequently, vehicle head lamps under varying load conditions often make people in the opposing vehicle uncomfortable, and even worse, can cause an accident. This paper presents an active vehicle lighting mechanism to automatically adjust its aiming point, or cut-off line, in order to compensate the change in vehicle inclination resulting from load variations. The effectiveness of the proposed method is demonstrated through a set of simulations and experiments with a real vehicle.