• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.37.3-37.3
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• 2008

STJ(Superconducting Tunnel Junction) technique offers next generation photon detectors exhibiting high energy resolution, high quantum efficiency and photon counting ability over the broad wavelength range from X-ray to NIR. We report the succcess in fabrication of Ta/Al-AlOx-Al/Ta and Nb/Al-AlOx-Al/Nb micro structure deposited on sapphire substrates using various techniques including UV photolithography, DC Sputtering, RIE, and PECVD technique. The characterization experiment was undertaken in an Adiabatic Demagnetization Refrigerator at an operating temperature below 50mK. The details of experimental investigations for electrical characterization of STJ of $20\sim80{\mu}m$ in side-lengths are discussed. The measured I-V curves were used to derive The detector performance indicators such as energy gap, energy resolution, normal resistance, normal resistivity, dynamic resistance, dynamic resistivity, and quality factor.

• Wind and Structures
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• v.30 no.3
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• pp.275-288
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• 2020

High-rise buildings are very slender and flexible. Their low stiffness values make them vulnerable to horizontal loads, such as those associated with wind or earthquakes. For high-rise buildings, the threat to serviceability caused by wind-induced vibration is an important problem. To estimate the serviceability under wind action, the response acceleration of a building at the roof height is used. The response acceleration is estimated by the same wind speed at all wind directions. In general, the effect of wind direction is not considered. Therefore, the response accelerations obtained are conservative. If buildings have typical plans and strong winds blow from relatively constant wind directions, it is necessary to account for the wind direction to estimate the response accelerations. This paper presents three methods of evaluating the response accelerations while considering the effects of wind direction. These three serviceability evaluation methods were estimated by combining the wind directional frequency data obtained from a weather station with the results of a response analysis using wind tunnel tests. Finally, the decrease in the efficiencies of the response acceleration for each serviceability evaluation method was investigated by comparing the response acceleration for the three methods accounting for wind direction with the response acceleration in which wind direction was not considered.

• Explosives and Blasting
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• v.23 no.1
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• pp.31-39
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• 2005

This study is based on the reseach about conte. track$(Dugso\~wonju)$ double line electric railway tunnel. Authors conducted test blasting to examine the effect of blasting pollution. To be conducted safe and effective work by using this result studies sailable substitution excavation method. No-vibration section generates continuously the vibration of breaker working to go abreast necessarily secondary fragmentation working and according to judging that application is actually difficult in case of the condition of study site, the period of construction, the cost of construction, the efficiency of construction, pre-heavy caliber horizontally boring working + line drilling method + vibration control secondary blasting method excavation working is possible from level within blast vibration standard.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.324-333
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• 2014

In this study, physiological status of locomotive engineers were measured through EEG, ECG, EDA, PPG and respiration signals from 6 subjects to evaluate their arousal status during train operating. Existence of tunnels and mechanical vibration of train using 3-axes acceleration sensors were recorded simultaneously and were correlated with operator's physiological status. As the result of the analyzed subjects' physiological signals, mean SCR was increased in the section where more body movement is required. The RR interval was decreased before and after train stop due to the higher level of mental tension. The intensity of beta wave of EEG was found to be higher before and after train stop and tunnel section due to the increased mental arousal and tension. Therefore, it is expected that the outcomes of the physiological signals explored in this study can be utilized as the quantitative assessment methods for the arousal status to be used for sleepiness prevention system for vehicles operators which can greatly contribute to public transportation system safety.

• Journal of Korean Association for Spatial Structures
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• v.8 no.1
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• pp.69-76
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• 2008

The wind monitoring systems are installed in high-rise buildings to record wind response data. The measured buildings are located in Busan and Sokcho. The measured wind data are analysed in this paper to obtain the mean wind speed and direction, turbulence intensity and gust factor. By using the correlation between gust factor and turbulence intensity, the expression for gust factor based on wind data measured from the building is suggested. The field measurement data obtained here are useful for the validation of wind tunnel tests and the future design of tall building.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2224-2229
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• 2008

High-Speed train has been developed and it becomes faster and environmental friendly. As trains run faster, Noise of trains is generated mainly by aerodynamic disturbance. Pantograph, both ends of trains, and gaps of coaches which are thought to be aerodynamic noise's factors are primarily studied. Pantograph is a similarly shaped metal framework on the roof of an electric high speed train, transmitting current from an overhead electric catenary wire. Panhead which contacts electric wires directly looks like a bluff strut, goes through flows, is sensitive to external disturbances and is one of the most important factors which decide whole vehicles' driving ability. In this study, aerodynamically robust optimized pantograph panhead shape is designed and then evaluated through subsonic wind tunnel test. To compare these with existing panhead rectangular shapes or circular cylinder shapes, By visualizing strong vortex flow patterns which are main noise sources, characteristics are compared and analyzed

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1776-1781
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• 2015

Electric power trains receive electric power from overhead cables via a pantograph system. Power collector system in trains increase the cross section of tunnel and require a massive coreless filter reactor in propulsion inverter because of the power disturbance by contact loss phenomenon of a train. In this paper we proposed a wireless train which can run to next station with charging energy of ultra-capacitor module block. We designed DC-DC converter to charge and discharge ultra-capacitor modules by using Next Train running test results and confirm the feasibility of the proposed system through simulation.

• Journal of Veterinary Clinics
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• v.34 no.1
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• pp.54-57
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• 2017

A 1-year-old castrated male Schnauzer dog was presented with heart murmur. Auscultation revealed systolic murmur located at the left heart base (grade 5/6). There were no remarkable findings on thoracic radiographs. Two-dimensional echocardiography revealed subaortic tunnel-like obstruction at the entrance to the left ventricular outflow tract. Anterior mitral valve leaflet appeared to be tethered to septum with minimal motion. Chordae tendineae was abnormally thickened. Color Doppler analysis revealed turbulent flow starting below the aortic valve. Mitral regurgitation was presented during systole. Spectral Doppler recordings revealed high velocity flow through the aorta and mitral regurgitation. Based on echocardiographic examination, the dog was diagnosed with subaortic stenosis concurrent with mitral dysplasia. The patient was medicated with ${\beta}-blocker$ and diuretics. It has been doing well without apparent clinical signs at 2 year after the diagnosis.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.1
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• pp.95-107
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• 2017

In this study, a preliminary study was undertaken for development of a tunnel incident automatic detection system based on a machine learning algorithm which is to detect a number of incidents taking place in tunnel in real time and also to be able to identify the type of incident. Two road sites where CCTVs are operating have been selected and a part of CCTV images are treated to produce sets of training data. The data sets are composed of position and time information of moving objects on CCTV screen which are extracted by initially detecting and tracking of incoming objects into CCTV screen by using a conventional image processing technique available in this study. And the data sets are matched with 6 categories of events such as lane change, stoping, etc which are also involved in the training data sets. The training data are learnt by a resilience neural network where two hidden layers are applied and 9 architectural models are set up for parametric studies, from which the architectural model, 300(first hidden layer)-150(second hidden layer) is found to be optimum in highest accuracy with respect to training data as well as testing data not used for training. From this study, it was shown that the highly variable and complex traffic and incident features could be well identified without any definition of feature regulation by using a concept of machine learning. In addition, detection capability and accuracy of the machine learning based system will be automatically enhanced as much as big data of CCTV images in tunnel becomes rich.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.2
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• pp.155-162
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• 2005

This paper presents an invetigation into the cause of deterioration of wet surrounding RC structures subjected to checmical attacks such as sewage. The antibacterial-reforming agent is developed after determining the permeability of the RC structure. After application of the anitbacterial-reforming agent through SEM, the permeability, compressive strength properties and the micro-structure of the concrete were evaluated for durability. In addition, the antibacterial-reforming agent was combined with a protective coating for the wet surrounding RC structure and evaluated for durability. The combined effect of the antibacterial-reforming agent and the protective coating were evaluated in field tests in both sewer system and tunnel sites.