• Title/Summary/Keyword: 상대 깊이

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The Gradient Variation of Thermal Environments on the Park Woodland Edge in Summer - A Study of Hadongsongrim and Hamyangsangrim - (여름철 공원 수림지 가장자리의 온열환경 기울기 변화 - 하동송림과 함양상림을 대상으로 -)

  • Ryu, Nam-Hyong;Lee, Chun-Seok
    • Journal of the Korean Institute of Landscape Architecture
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    • v.43 no.6
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    • pp.73-85
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    • 2015
  • This study investigated the extent and magnitude of the woodland edge effects on users' thermal environments according to distance from woodland border. A series of experiments to measure air temperature, relative humidity, wind velocity, MRT and UTCI were conducted over six days between July 31 and August 5, 2015, which corresponded with extremely hot weather, at the south-facing edge of Hadongsongrim(pure Pinus densiflora stands, tree age: $100{\pm}33yr$, tree height: $12.8{\pm}2.7m$, canopy closure: 75%, N $35^{\circ}03^{\prime}34.7^{{\prime}{\prime}}$, E $127^{\circ}44^{\prime}43.3^{{\prime}{\prime}}$, elevation 7~10m) and east-facing edge of Hamyangsangrim (Quercus serrata-Carpinus tschonoskii community, tree age: 102~125yr/58~123yr, tree height: tree layer $18.6{\pm}2.3m/subtree$ layer $5.9{\pm}3.2m/shrub$ layer $0.5{\pm}0.5m$, herbaceous layer coverage ratio 60%, canopy closure: 96%, N $35^{\circ}31^{\prime}28.1^{{\prime}{\prime}}$, E $127^{\circ}43^{\prime}09.8^{{\prime}{\prime}}$, elevation 170~180m) in rural villages of Hadong and Hamyang, Korea. The minus result value of depth means woodland's outside. The depth of edge influence(DEI) on the maximum air temperature, minimum relative humidity and wind speed at maximum air temperature time during the daytime(10:00~17:00) were detected to be $12.7{\pm}4.9$, $15.8{\pm}9.8$ and $23.8{\pm}26.2m$, respectively, in the mature evergreen conifer woodland of Hadongsongrim. These were detected to be $3.7{\pm}2.2$, $4.9{\pm}4.4$ and $2.6{\pm}7.8m$, respectively, in the deciduous broadleaf woodland of Hamyansangrim. The DEI on the maximum 10 minutes average MRT, UTCI from the three-dimensional environment absorbed by the human-biometeorological reference person during the daytime(10:00~17:00) were detected to be $7.1{\pm}1.7$ and $4.3{\pm}4.6m$, respectively, in the relatively sparse woodland of Hadongsongrim. These were detected to be $5.8{\pm}4.9$ and $3.5{\pm}4.1m$, respectively, in the dense and closed woodland of Hadongsongrim. Edge effects on the thermal environments of air temperature, relative humidity, wind speed, MRT and UTCI in the sparse woodland of Hadongsongrim were less pronounced than those recorded in densed and closed woodland of Hamyansangrim. The gradient variation was less steep for maximum 10 minutes average UTCI with at least $4.3{\pm}4.6m$(Hadongsongrim) and $3.5{\pm}4.1m$(Hamyansangrim) being required to stabilize the UTCI at mature woodlands. Therefore it is suggested that the woodlands buffer widths based on the UTCI values should be 3.5~7.6 m(Hamyansangrim) and 4.3~8.9(Hadongsongrim) m on each side of mature woodlands for users' thermal comfort environments. The woodland edge structure should be multi-layered canopies and closed edge for the buffer effect of woodland edge on woodland users' thermal comfort.

S-wave Relative Travel Time Tomography for Northeast China (중국 만주지역 S파 상대주시 토모그래피)

  • Kim, Yong-Woo;Kim, Hyo-Ji;Lim, Jung-A;Chang, Sung-Joon
    • Geophysics and Geophysical Exploration
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    • v.21 no.1
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    • pp.26-32
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    • 2018
  • The Northeast China is an important site geologically and geophysically because of a huge volcano called Mt. Baekdu, which is one of the largest volcanoes in the world. Signs of eruption have been recently observed and people are keen to its behavior. We carried out relative travel time tomography to investigate the velocity structure between 100 ~ 600 km depth beneath Northeast China. We used teleseismic data during 2009 ~ 2011 recorded in NecessArray provided by IRIS (Incorporated Research Institute for Seismology). The relative observations were obtained by using the multi-channel cross-correlation method. Based on the tomographic results, we observed that the locations beneath which low-velocity zones are observed coincide with the locations of several volcanic regions in Northeast China. A low-velocity anomaly is revealed beneath Mt. Baekdu down to 600 km depth, which is thought to the main origin of the magma supply for Mt. Baekdu. Another low velocity anomaly is observed beneath east of the Datong volcano down to around 300 km depth, which is inferred to be related to an upwelling from deep mantle. We observed a low velocity anomaly beneath the Wudalianchi volcano down to around 200 km depth, which may imply that this volcano has been formed by an upwelling from the asthenosphere.

Autonomous Mobile Robot System Using Adaptive Spatial Coordinates Detection Scheme based on Stereo Camera (스테레오 카메라 기반의 적응적인 공간좌표 검출 기법을 이용한 자율 이동로봇 시스템)

  • Ko Jung-Hwan;Kim Sung-Il;Kim Eun-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.1C
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    • pp.26-35
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    • 2006
  • In this paper, an automatic mobile robot system for a intelligent path planning using the detection scheme of the spatial coordinates based on stereo camera is proposed. In the proposed system, face area of a moving person is detected from a left image among the stereo image pairs by using the YCbCr color model and its center coordinates are computed by using the centroid method and then using these data, the stereo camera embedded on the mobile robot can be controlled for tracking the moving target in real-time. Moreover, using the disparity map obtained from the left and right images captured by the tracking-controlled stereo camera system and the perspective transformation between a 3-D scene and an image plane, depth information can be detected. Finally, based-on the analysis of these calculated coordinates, a mobile robot system is derived as a intelligent path planning and a estimation. From some experiments on robot driving with 240 frames of the stereo images, it is analyzed that error ratio between the calculated and measured values of the distance between the mobile robot and the objects, and relative distance between the other objects is found to be very low value of $2.19\%$ and $1.52\%$ on average, respectably.

2D Spatial-Map Construction for Workers Identification and Avoidance of AGV (AGV의 작업자 식별 및 회피를 위한 2D 공간 지도 구성)

  • Ko, Jung-Hwan
    • Journal of the Institute of Electronics and Information Engineers
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    • v.49 no.9
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    • pp.347-352
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    • 2012
  • In this paper, an 2D spatial-map construction for workers identification and avoidance of AGV using the detection scheme of the spatial coordinates based on stereo camera is proposed. In the proposed system, face area of a moving person is detected from a left image among the stereo image pairs by using the YCbCr color model and its center coordinates are computed by using the centroid method and then using these data, the stereo camera embedded on the mobile robot can be controlled for tracking the moving target in real-time. Moreover, using the disparity map obtained from the left and right images captured by the tracking-controlled stereo camera system and the perspective transformation between a 3-D scene and an image plane, depth map can be detected. From some experiments on AGV driving with 240 frames of the stereo images, it is analyzed that error ratio between the calculated and measured values of the worker's width is found to be very low value of 2.19% and 1.52% on average.

Mixing Performance of Unlike Doublet Impinging Liquid Jets (이중 충돌제트의 혼합 성능 연구)

  • Jo, Yong Ho;Lee, Seong Ung;Yun, Ung Seop
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.4
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    • pp.82-91
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    • 2003
  • Experiments to investigate the mixing performance of unlike doublet impinging jets are conducted. Reynolds number of simulants used in this study rages from 1.0 to 1.5 Cold flow test is performed to investigate the hydrodynamic effect and spray of the impinging jets are collected locally and calculated by using Rupe's mixing efficiency equation. Momentum exchanges and relative velocity ratio between two jets are taken as the main parameter to represent the effect of enlargement of the orifice diameter. As diameter ratio increases, the corresponding momentum ratio where maximum mixing efficiency occurs and relative velocity at the maximum mixing efficiency ranges 0.6 to 0.7, respectively. Penetration depth can be taken as a prominent parameter to estimate the mixing efficiency.

Damping of Water Waves over Permeable Bed of Finite Depth (유한한 깊이의 투수층에 의한 파랑의 감쇠)

  • Kim, Gun-Woo;Lee, Myung-Eun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.18 no.3
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    • pp.199-205
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    • 2012
  • In this study, wave transformation by damping due to the permeable bed of finite depth is investigated. The relationship between wave damping rate and relative water depth are presented. The damping rate is used in the eigenfunction expansion method to calculate the wave dissipation over the permeable bed. For a permeable shoal, the eigenfunction expansion model result is compared with that of the integral equation method to show good agreement. The model is also used to examine the wave reflection over the permeable planar slope of various frequency. It has been found that in general relatively short waves are more influenced by the permeability of the permeable seabed than relatively long waves unless the water depth is so large that the influence of permeable bed on surface water waves disappears.

Use Impact on Environmental Deteriorations of Trail and Campsite in Chirisan National Park (지리산국립공원의 등산로 및 야영장 주변 환경훼손에 대한 이용영향)

  • 권태호;오구균;권순덕
    • Korean Journal of Environment and Ecology
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    • v.5 no.1
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    • pp.91-103
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    • 1991
  • Use impacts on environmental deteriorations of trail and campsite were studied in Chirisan National Park in 1991. The entire width, bare width and maximum depth of trail as the trail condition were significantly greater on the more heavily used trail. Trail conditions, especially altitude, entire width and maximum depth of deteriorated points which were surveyed at the total of 82 were significantly different from those of non-deteriorated points. On the ridge trail, the damaged are more severe than Class 4 reaches about 34,000$m^2$ and use impacts on campsite and deterioration were also accelerated. The dominant trees of the upper layer in trail edge vegetation are changed from Carpinus tschonoskii to Quercus serrata, Carpinus laxiflora and to Quercus mongolica, Carpins laxiflora at Hwaeomsa trail, and from Quercus serrata to Quercus mongolica at Piagol trail. Also Lespedoza maximowiczii, Symplocos chinensis, Deutzia prunifolia, Weigela Subsessilis appear as the dominant lower species at Hwaeomsa trail, L. maximowiczii, S. chinensis, Stephanandra incisa, Rhododendron schlippenbachii for Piagol trail.

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A Study on the Integrity Assessment of Bare Concrete Bridge Deck based on the Attenuation of Radar Signals (레이더 신호의 감쇠특성을 고려한 일체식 콘크리트 교량 바닥판의 상태평가 방법 고찰)

  • Rhee, Ji-Young;Choi, Jae-Jin;Kim, Hong-Sam;Park, Ko-Eun;Choi, Myeong-Jin
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.20 no.4
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    • pp.84-93
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    • 2016
  • The signal characteristic of radar wave on concrete decks is determined by the attenuation of the radar due to the conversion of EM(Electromagnetic) energy to thermal energy through electrical conduction, dielectric relaxation, scattering, and geometric spreading. In this study, it is found that the attenuation of radar signal received on top rebars in bare deck concrete with 2 way travel time shows a general decreasing linear trend because of its same relative permittivity and conductivity. The radar signal after depth-normalization, can then be interpreted as being principally influenced by the content of chlorides penetrating cover concrete, which caused corrosion of rebars in bridge decks.

Flash flood risk indicator for ungauged area of Seoul metropolitan region (수도권 미계측지역에 대한 돌발홍수위험도 산정 연구)

  • Lee, Byong Ju
    • Proceedings of the Korea Water Resources Association Conference
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    • 2016.05a
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    • pp.94-94
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    • 2016
  • 돌발홍수는 수십 $km^2$ 이하의 유역에서 강우가 발생한 후 6시간 이내의 단시간에 홍수징후가 나타나는 현상으로 정의될 수 있다. 돌발홍수를 잘 예측하기 위해서는 국지적으로 발생하는 집중 호우를 잘 예측해야 하며 유역내 공간적인 수문반응해석을 통해 돌발홍수를 예측하는 기술이 요구된다. 본 연구에서는 유역내 공간적인 수문반응을 잘 모의하기 위해 TOPLATS 지표해석모형을 이용하였다. TOPLATS(TOPMODEL based Land Atmosphere Transfer Scheme) 모형은 물수지와 에너지수지를 통해 단위격자에 대한 실제증발산량, 토양수분량, 지하수면깊이, 지표유출량, 잠열, 현열, 지열, 순복사량 등을 모의하며 소유역단위로 지하수면깊이를 재분포시키는 특성을 가지고 있다. 돌발홍수 위험도를 산정하기 위해 실제 돌발홍수 피해사례를 조사하였으며 피해지역과 대응되는 격자 수문성분과의 상관성 분석을 통해 돌발홍수 위험도 모형을 산정하였다. 대상지역은 수도권 전체지역을 모의하기 위해 한강, 임진강, 안성천 유역을 대상지역으로 선정하였다. 수도권 지역은 약 11,930 km2이며 2009~2012년동안 총 38건의 돌발홍수 피해사례가 신고되었다. 기상자료는 기상청 AWS와 ASOS 시단위 강우, 기온, 상대습도, 풍속, 일조, 기압자료를 이용하였다. 돌발홍수 피해사례 38건에 대해 대응되는 모의격자의 수문성분을 분석하였으며 27(71%)에서 구조요청시점에 대해 강우량, 지표유출량, 토양수분량, 지하수면깊이가 적절하게 모의되는 것을 확인하였다. 강우조건에 따른 돌발홍수 위험도는 구조요청시점 기준 선행시간 4~6시간까지 71~87%, 구조요청시점으로 한정된 0시간에서는 42~52%로 나타났다. 이상의 결과로부터 지표해석모델을 이용한 격자 수문성분과 통계적 돌발홍수지수모형으로부터 산정된 돌발홍수 위험도는 산지 미계측지역에 대한 돌발홍수를 예측하는데 활용될 수 있을 것으로 판단된다.

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Numerical Analysis of Dynamic Centrifuge Model Tests Using an Effective Stress Model (유효응력모델을 이용한 동적 원심모형실험의 수치해석)

  • Park Sung-Sik;Kim Young-Su
    • Journal of the Korean Geotechnical Society
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    • v.22 no.1
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    • pp.25-34
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    • 2006
  • In this study an effective stress numerical procedure is used to assess the results of dynamic centrifuge tests under high effective stress. The centrifuge models consist of loose Nevada sand with an initial vertical effective stress of 380kPa at depth, and they are modeled as a one-dimentional soil column. Liquefaction occurred up to 37m or 22m at depth, and the onset of liquefaction triggering was opposite to the conventional liquefaction evaluation procedure. In other words, liquefaction occurs first at the top and propagates downward as shaking continues. The results observed in centrifuge tests are reasonably predicted by the effective stress model. It is noted that the degree of initial saturation and additional densification at depth arising from the application of the high acceleration field play a key role in capturing the results of dynamic centrifuge tests.