• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.2
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• pp.120-130
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• 2007

A oxygen generating closed-circuit SCBA for escape from fire will be newly developed and then a program for estimating service time for it should be required. A SCBA made on an experimental basis consisted of five components such as half facepiece (mask), $KO_2$ box, oxygen reservoir, $CO_2$ remover and hood. The half mask had a good fitting performance since fit factors for 10 subjects were all above 100. It was found that height of subjects should be the best variable to estimate service time. Measured service time was inversely correlated with height of subjects. Service life time could be estimated by interpolation and extrapolation using inverse relationship between height and measured service time, for example, 28 minutes for male and female of 170 cm during resting, 10 minutes at the walk of 4 km/h and 5 minutes at the walk of 6 km/h considering safety margin of 20%. The study implies that program for estimating service time for the SCBA should require subject's height, speed of walk (4 km/h and 6 km/h) and fit testing. Considering safety margin, selecting younger subjects would be better. The study on the number of subjects and selecting facial dimensions should be more needed for the final program.

• Journal of Korean Society of Transportation
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• v.29 no.1
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• pp.47-55
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• 2011

The purpose of this study was to determine the legibility distance for traffic road sign and traffic sign, fixation duration and number of fixation during the time of recognition of traffic road signs under different vision conditions. This experiment was conducted on a closed-road circuit which has realistic driving road and environment Each participant drove the real vehicle for the experiment and specially built traffic road sign for the experiment and traffic road signs on the side of closed-road circuit were used. Different vision conditions were simulated using spectacle lenses to reach visual acuity 1.0 and 0.8 and it was 1.2 without spectacles and each participant tested under 3 vision conditions.. The result of this study demonstrated that there was a significant difference on legibility distance between visual acuity of 1.2 and 0.8 and there were also significant difference on fixation duration and number of fixations with smaller traffic signs. This study demonstrated the importance of vision correction for driving at night-time, also showed there would be difference on legibility distance and efficiency of eye movement such as fixation duration and number of fixation despite of satisfied visual acuity for driver's license requirement.

• Journal of Digital Contents Society
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• v.19 no.5
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• pp.1003-1010
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• 2018

When an applicant requests the emergency situation call or safe return service using a smart device, the smart surveillance service can select the CCTV(closed circuit television) cameras around the applicant using applicant's location information, then automatically takes a photograph to track the applicant. Since the surrounding CCTV camera shoots the applicant continuously using location information and the applicant can be observed by the monitor agent in real time, this service can be very helpful in an applicant's emergency situation or safe return. The existing smart surveillance service does not consider the priority of the emergency situation call and safe return service. Therefore, there is the disadvantage that the applicant who requests an emergency situation call service can not be photographed when safe return service has already preoccupied CCTV cameras which are capable of taking a picture of the applicant. The proposed smart surveillance service improves this disadvantage by using service priority.

• The Journal of Korean Institute of Information Technology
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• v.17 no.6
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• pp.115-122
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• 2019

CCTV(Closed-Circuit Television) is increasingly exposed to CCTV per person as the number of installations increases every year for accident prevention and facility safety. The intelligent video surveillance system technology is attracting attention to the privacy protection of exposed subjects. The intelligent video surveillance system performs a process for the privacy protection so as to perform the action type of the subject and the judgment of the situation in the simple identification of the photographed image data, or to prevent the information, from which the information of the photographed subject is exposed. The proposed technique is applied to the video surveillance system and converts the original image information taken from the video surveillance system into similar image information so that the original image information is not leaked to the outside. In this paper, we propose an image conversion mechanism that inserts a virtual face image that approximates a preset similarity.

• Journal of Magnetics
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• v.4 no.3
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• pp.98-101
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• 1999

In this work we htave constructed an under water sonar transducer using Terfenol-D rod employing open magnetic circuit. Normally Sonar transducer using Terfenol-D was designed under closed magnetic flux return path, and permanent magnet for dc bias marnetic field, but high magnetic field should be applied to the transducer coil for high sound power and it brings temperature increase inside of the transducer. To improve this heat dissipation problem, we have designed an open magnetic circuit type transducer and we can get 200 dB (re. 1 Pa @ 1m) sound power for the input power of 650 VA.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.652-655
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• 2003

This paper is about the recent development of the magnetic impact actuator for endoscope. The developed magnetic impact actuator has many problems to arrange in the system body. Because the magnetic impact actuator need a permanent magnet as an impacter, so the magnetic interference among magnets can not be eliminated. This interference causes the system size bigger. We need a new actuator design to solve these problems. One of the good solutions is to use the closed electro-magnetic circuit. This kind of circuit enhances the actuators to be independent. It is written about the design of the electro-magnetic circuit and simulation using Maxwell(version 9.0)

• Journal of the Speleological Society of Korea
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• no.87
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• pp.8-13
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• 2008

The automatic firewall block and fire alarm system was embodied by using gas circuit and wireless communication equipment, using a smoke sensor (ST-QA1A) and RF Module. OR-CAD was also used for testing circuit system and experiment circuit after assembling circuit. As a result in experiment, the gas sensor detected well an imaginary smoke and worked reliably for driving action of firewall block motor and wireless warning alarm. Through the smoke sensitive perception from the fire, the warning alarm and the preventing fire propagation from the specific closed region were verified reliably. The gas sensor and RF module for firewall and fire alarm system were actually available.

• IEIE Transactions on Smart Processing and Computing
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• v.5 no.1
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• pp.22-28
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• 2016

Multi-loop control of a boost converter needs a current-sensing circuit to detect the inductor current. Current sensorless multi-loop control reduces the cost, size and weight of the converter. The Luenberger observer (LO) is widely used to estimate the inductor current for current sensorless control of a switching converter. However, the design of the LO-based sensorless multi-loop control has not been well presented, so far. In this paper, a closed-loop characteristics evaluation method is proposed to design an LO-based current sensorless multi-loop control for boost converters. Simulations show evaluations of the closed-loop characteristics. Practical experiments on a digital processor confirm the simulations.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.11
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• pp.1112-1118
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• 2007

It was discussed to identify Thiele Small Parameters for Pseudo loudspeaker within 10mm grade microspeaker attached to closed-box using known dynamic mass of moving parts. Also, enhanced circuit model for vented-box micro speaker system was used to more accurately simulate electrical impedance curves for real vented-box microspeaker system and compared to test results. Consequently, it showed that micro speaker could be modeled by pseudo loudspeaker TS parameters similar to general loudspeaker. Vented-box microspeaker model with pseudo loudspeaker TS parameters was well suited to describe real microspeaker. Also, it was proposed to estimate volume of rear closed-box of microspeaker without design specifications.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.90-92
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• 2001

The lift and drag forces on various magnet moving with a velocity is developed above a closed loop coil. These forces are affect by resistance and inductance of circuit, velocity of magnet. To obtain strong magnetic flux density, the magnet is replaced by Halbach array. This paper presents analysis of force between linear motion Halbach array and a closed loop having the constant resistance and inductance as a various speed.