• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.1
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• pp.47-58
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• 2020

The interest in the use of shield TBM (Tunnel Boring Machine) on the tunnel excavation has been increased rapidly in Korea. The shield TBM tunnel is generally designed as non-drainage tunnel. Consequently, if water leakage through the segment joints happens, big problems on the usage and stability of tunnel can be occurred. In this study, the variation of waterproof capacity of hydrophilic rubber waterstop by the construction error and excessive displacement of segment was studied. In particular, the waterproof capacity of each of single and double layer arrangements of hydrophilic rubber waterstop was examined to verify the efficiency of the double layer arrangement. The test results show that the single layer and double layer hydrophilic rubber waterstop showed the same waterproof performance. hydrophilic rubber waterstop has favorable on the offset, however unfavorable on the gap.

• Journal of the Korean Association of Geographic Information Studies
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• v.26 no.2
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• pp.68-81
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• 2023

This study aims to establish a scenario based on the spacing and arrangement of the roadside trees to reduce heat waves and fine dust in cities that occurred during the urbanization process and to quantitatively analyze the degree of reduction. The ENVI-met 5.0.2v model, a micro-climate simulation program, was used to analyze the degree of improvement in the thermal environment and fine dust according to the roadside tree scenario. As a result of temperature analysis according to street tree spacing, the narrower the distance between roadside trees, the lower the temperature during the day as the number of planted trees increased, and a similar pattern was shown regardless of the distance between roadside trees in the morning and evening. In the case of fine dust emitted from the road, the concentration of fine dust increased slightly due to the increase in roadside trees, but the concentration of sidewalks where people walk increased slightly or there was no difference because of blocking fine dust on trees. The temperature according to the arrangement of street trees tended to decrease as the number of planted trees increased as the arrangement increased. However, not only the amount of trees but also the crown projected area was judged to have a significant impact on the temperature reduction because the temperature reduction was greater in the scenario of planting the same amount of trees and widening the interval of arrangement. In terms of the arrangement, the fine dust concentration showed a difference from the results according to the interval, suggesting that the fine dust concentration may change depending on the relationship between the main wind direction and the tree planting direction. By quantitatively analyzing the degree of thermal environment and fine dust improvement caused by roadside trees, this study is expected to promote policies and projects to improve the roadside environment efficiently, such as a basic plan for roadside trees and a project for wind corridor forests.

• Journal of KSNVE
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• v.5 no.2
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• pp.197-206
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• 1995

Microphone array is designed to measure the equivalent source height of vehicle noise. The equivalent source position is defined for an arbirary distribution of acoustic sources above a perfectly reflecting plane and a microphone array for its measurement is developed. The normalized errors of the measured equivalent source heights are defined including the effects of background noise, the geometric near field, and source size. Normalized errors of the measured source heights obtained by a nemerical simulation for each parameter lead to optimization of the microphone spacing and to the design of an array which gives the equivalent source height as a function of frequency. The performance of the designed array is verified using the stationary loudspeaker experiments.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.846-851
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• 2000

4-state 바코드의 정보는 우편번호, 배달순서코드, 고객 정보 등을 수록되며, 판독율 향상을 위한 오류정정 코드워드를 적용할 수 있다. 이 4-state 바코드는 우편물 자동구분처리의 효율화 및 우편물류의 정보표현, 전달, 처리를 효율적으로 지원되도록 개발하고 있다. 본 논문은 우편물 접수 및 처리과정에서 필요로 하는 4-state 고객 바코드 인쇄규격 검증 및 판독시스템 개발에 관한 것으로 4개의 높이로 구성된 바들의 특성과 바의 두께 및 공간 값이 균일한 간격으로 바가 인쇄되는 특징을 고려하여 Laser Diode 배열방법을 적용하였다. 또한, 우편물을 자동으로 이송시키고, 일정한 영역에 배열한 Laser Diode에 의하여 바의 두께, 공간, 높이 값을 정확하게 판독될 수 있도록 한 것이다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.04a
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• pp.7-7
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• 1999

충돌/유출냉각은 연소실 벽면 등과 같이 열부하가 많이 걸리는 영역에서 고온의 연소가스로부터 표면을 보호하는 막냉각과 더불어 내부에 다공성 판을 설치하여 충돌제트에 의해 내부표면을 냉각시켜 가스터빈엔진의 고온요소의 냉각성능을 극대화시키는 방법 중의 하나이다. 이와 같은 냉각방법을 적용하면 벽면을 충돌제트에 의한 냉각과 함께 냉각유채를 막냉각에 활용함으로써 냉각효율을 극대화할 수 있다. 본 연구에서는 국소적인 값들을 획득하기 용이한 물질전달실험방법의 하나인 나프탈렌 승화법을 이용하여 수직으로 분사되는 충돌제트에 의한 유출판 내면에서의 열/물질전달특성을 분사판(injection plate)과 유출판(effusion plate) 사이의 높이, 분사제트의 속도, 분사홀간의 배열을 변화시켜가며 유출판만이 있는 경우와 비교, 분석하였다. 분사홀과 유출홀의 관 사이의 간격은 0.33d에서 10d까지 변화시켜가며 그 효과를 관찰하였으며, 홀배열 효과를 보기 위하여 2가지 홀배열(staggered array, shifted array)에 대하여 실험하였다. 또한 분사제트의 속도효과를 고찰하기 위하여 분사제트의 Rc$_{d}$=5,000-12,000까지 변화시켜가며 실험을 수행하였다.

• The Journal of the Acoustical Society of Korea
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• v.34 no.6
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• pp.479-486
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• 2015

A triplet line array has a capability for solving left/right ambiguity problem and high directivity of line array. For this, high computational powers and correlation between nearby sensors must be considered. Hardware powers are dramatically increased, so various adaptive beamforming techniques and signal processing techniques can be adopted for large triplet line array. To investigate the optimum signal processing method and improve the target detection capability, we need to analyze the noise correlation among the triplet line array sensors in real environment. In this paper we analyze the experimental data in the East Sea, investigate noise correlation between three hydrophones in triplet sensors, among the triplet sensors and time varying properties. Based on the acquired results, it is possible to verify some information for beamforming and signal processing methods with considering the properties of the triplet line array.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.43-55
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• 2013

In this paper, we propose a cylindrical active phased array antenna of Beam Steering Characteristics in the horizontal plane(H-plane) and vertical plane(E-Plane) on the cylinder form array structure. We design the bent dipole antenna of the cylindrical array structure adapted excellent mutual-coupling characteristics, designed and manufactured the cylindrical array antennas and power combiner/divider unit for power dividing and combining on the antenna. The radiating elements array spacing of Cylindrical array antenna were determined to avoid grating lobes at half power beam steering. Beam steering of the antenna was implemented with 6-bit phase shifter in the transceiver and have been designed based on the characteristics the antenna beam steering at -24 degrees to 24 degrees horizontal, vertical 0 degrees to 36 degrees beam steering. A cylindrical active phased array antenna that produced for verification the performance of the antenna are measured radiation characteristics in accordance with beam steering at L-Band.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.3
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• pp.75-79
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• 2008

Transmission line characteristics in microstrip line is used to in this paper. 5-microstrip lines composed of various spacing between them suggests characteristics of a diplexer in simulation. By applying the simiulation results, the diplexer realized shows better results of flat responses in bandpass characteristics and bandstop characteristics around 15 dB than symmetric spacing one.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.262-267
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• 1997

금속형 사용후핵연료 관리모형으로 직경 3 cm, 길이 248.5cm인 금속봉을 19개 장전한 캐니스터가 x-y 방향으로 무한 격자배열된 경우에 대해 캐니스터의 두께, 간격 및 외부의 공기중 수분농도의 변화에 따른 핵임계도 분석을 수행하였다. 미임계한계치(k$_{eff}$=0.95) 근방에서 최대 핵임계도를 나타내는 각 인자값을 구하고, 미임계 상태를 유지하는 조건을 제시했다. 그 결과, 캐니스터의 두께가 7mm인 경우의 최대 핵임계도 값은 0.94401 $\pm$ 0.00050으로서, 공기중 수분농도가 0.34 g/㎤이고 간격이 4.8 cm인 경우에 나타났다. 8 mm인 경우의 최대 핵임계도 값은 0.91182 $\pm$0.00050이며, 캐니스터간의 간격이 4.4cm이고 공기중 수분농도가 0.35 g/㎤일 때 나타났다. 8 mm 캐니스터의 금속저장체 저장은 미임계 상태를 유지할 것으로 추정되었다.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.534-539
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• 2001

An experimental investigation of heat transfer characteristics on confined jet impinging plate using multiple slot jets has been performed. The effects of jet Reynolds numbers(Re=2000, 3950, 5900, 7900), dimensionlesss slot-to-plate distances(H/B=2, 4, 6, 8) and jet-to-jet distances(S=16B, 20B, 24B, 30B) on the local and average heat transfer coefficients have been examined. To clarify local heat transfer characteristics, naphthalene sublimation technique were used. From the experimental results, it was found that the local and average heat transfer rates increase with increasing jet Reynolds number. Measurements of local heat transfer coefficients produced by multiple of slot jets have given an indication of the nature of the interaction between jets and of the uniformity of heat transfer obtainable with various arrangements. At S/B=20, Re=7900 and H/B=6, maximum average Nusselt number is obtained.