• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.6
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• pp.417-426
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• 2019

Conventional visualization of PM (Particulate Matter)10 flows applies superimposition of concentration distribution maps and wind field maps. This method is efficient for small scale maps where only macro flow trends are of interest. However, in the case of urban areas, local flows are difficult to model at micro level using wind fields, and therefore different methods of flow extraction is deemed necessary. In this study, flow information is extracted and visualized directly from the PM10 density data by using the gravity model. This method has the advantage that additional information such as wind field is not necessary for estimating the intensity and direction of PM10 flow. The extracted spatio-temporal flow patterns of PM10 are analyzed with relation to traffic information.

• Journal of Korea Water Resources Association
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• v.42 no.1
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• pp.51-60
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• 2009

2/3 of the Imjin River Basin area is located in North Korea, so it was hard to acquire reliable rainfall and hydrological information. This point is one of the factors that has added to flood damage. In this study, flood runoff for the river basin was simulated using hydrological radar, which is installed in an effort to reduce flood damage in the Imjin River Basin, which habitually suffers from flood damage. The feasibility of the distributed flood model was reviewed for the river basin, which is lacking in hydrological data such as rainfall and recent soil data. Based on the hydrograph, observed value was not consistent partially because of insufficient data, but peak discharge and the overall pattern showed relatively precise runoff results which can be applied in actual work.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.414-414
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• 2017

토양수분은 지면환경에서 일어나는 수문 및 에너지 순환을 이해하는 데 있어 중요한 기상인자이다. 토양수분 현장관측은 땅속에 매설된 센서에 의해 상당히 정확하게 이루어지만, 관측점 수가 충분치 않아 공간적 연속성을 확보하지 못하는 어려움이 존재한다. 이에 광역적 및 연속적 관측이 가능한 마이크로파 위성센서가 토양수분 정보 획득을 위한 보조수단으로서 그 중요성이 부각되고 있다. 마이크로파 위성센서는 구름 등 기상조건의 제약을 받지 않으며, 1978년 이래 현재까지 여러 위성에 의해 25 km 및 10 km 해상도의 전지구 토양수분자료가 생산되어 왔다. 마이크로파 센서를 이용한 토양수분자료는 동일지점에 대하여 하루 2회 정도 산출되므로 적절한 시간분해능을 가지지만, 공간해상도가 최고 10 km로서 지역규모의 수문분석에 적용하기에는 충분치 않다. 이러한 토양수분자료의 공간해상도 문제 해결을 위하여 다양한 지면환경요소를 활용한 통계적 다운스케일링이 대안으로 제시되었다. 최근의 선행연구들은 대부분 방정식을 이용한 결합모형을 통해 통계적 다운스케일링을 수행하였는데, 회귀식과 같은 선형결합뿐 아니라 신경망이나 기계학습 등의 비선형결합에서도, 불가피하게 발생할 수밖에 없는 잔차(residual)로 인하여 다운스케일링 전후의 공간분포 패턴이 달라져버리는 문제를 안고 있었다. 회귀분석에 잔차의 공간내삽을 결합시킨 회귀크리깅(regression kriging)은 잔차보정을 통해 이러한 문제를 해결함으로써 다운스케일링 전후의 공간분포 일관성을 보장하는 기법이다. 이 연구에서는 회귀크리깅을 이용하여 일자별 AMSR2(Advanced Microwave Scanning Radiometer 2) 토양수분 자료를 10 km에서 1 km 해상도로 다운스케일링하고, 다운스케일링 전후의 자료패턴 일관성을 평가한다. 지면온도(LST), 지면온도상승률(RR), 식생온도건조지수(TVDI)는 일자별로 DB를 구축하였고, 식생지수(NDVI), 수분지수(NDWI), 지면알베도(SA)는 8일 간격으로 DB를 구축하였다. 이러한 8일 간격의 자료를 일자별로 변환하기 위하여 큐빅스플라인(cubic spline)을 이용하여 시계열내삽을 수행하였다. 또한 상이한 공간해상도의 자료는 최근린법을 이용하여 다운스케일링 목표해상도인 1 km에 맞도록 변환하였다. 우선 저해상도 스케일에서 추정치를 산출하기 위해서는 저해상도 픽셀별로 이에 해당하는 복수의 고해상도 픽셀을 평균화하여 대응시켜야 하며, 이를 통해 6개의 설명변수(LST, RR, TVDI, NDVI, NDWI, SA)와 AMSR2 토양수분을 반응변수로 하는 다중회귀식을 도출하였다. 이식을 고해상도 스케일의 설명변수들에 적용하면 고해상도 토양수분 추정치가 산출되는데, 이때 추정치와 원자료의 차이에 해당하는 잔차에 대한 보정이 필요하다. 저해상도 스케일로 존재하는 잔차를 크리깅 공간내삽을 통해 고해상도로 변환한 후 이를 고해상도 추정치에 부가해주는 방식으로 잔차보정이 이루어짐으로써, 다운스케일링 전후의 자료패턴 일관성이 유지되는(r>0.95) 공간상세화된 토양수분 자료를 생산할 수 있다.

• Journal of the Korean Wood Science and Technology
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• v.32 no.2
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• pp.19-25
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• 2004

This study was carried out to investigate a radial distribution of moisture contents (MCs) within a log cross section (LC) during oven-drying of 3 mm-thick circumferential slices cut from several domestic softwoods LCs.For Korean red pine, drying rate of sapwood slices during oven-drying represented much higher values than that of heartwood slices, and so sapwood with higher green MC early reached below fiber saturation point (FSP) rather than heartwood did. However, this distribution of moistures did not last for long duration. For Japanese larch, green MC of sapwood was approximately three times higher than that of heartwood. This similar distribution in MC was lasted until about 20% average MC. The MC was around uniform throughout the sapwood of Ginkgo when green and during oven-drying, although it was somewhat fluctuated. For Japanese cedar, the heartwood with so low moistures around FSP would begin to shrink from the beginning stage of drying, but the sapwood above hygroscopic MC prevents the heartwood from shrinking, and consequently, the heartwood or the transition wood goes into tension stress. The results for Japanese cypress showed that the green MCs of the sapwoods were much lower than those for heartwoods, and then this trend was continued until about 20% in average MC. For Chinese thuja, the green MCs of sapwoods were about 2 times as high as those of heartwood, but this along the radial gradient in MC rapidly became gentle during oven-drying.

• Korean Journal of Environmental Biology
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• v.22
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• pp.30-37
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• 2004

Peysistent oyganochlorine compounds (OCs) weve determined in sediments and bivalves from Gwangyang Bay. The concentrations of ∑PCB, ∑DDT, ∑HCH and ∑CHL in sediments were in the range of f 2.25∼11.4 ng g$\^$-1/, 0.16∼1.16 ng g$\^$-1/, nd∼0.51 ng g$\^$-1/, and 0.05∼0.79 ng g$\^$-1/, respectively. The overall OCs concentrations in sediments were below the effect range -median (ER-M) values toy benthic organisms suggested by NOAA (1991). Levels of PCB compounds a re relatively lower than other industrialized bays (Pusan Bay, Ulsan Bay, and Youngil Bay). OCs accumulated in bivalves were higher than those in sediments. In bivalves, the concentration ranges of ∑PCB, ∑DDT, ∑HCH and ∑CHL were 9.97∼31.7 ng g$\^$-1/, 7.54∼22.6 ng g$\^$-1/, 0.49∼2.0 ng g$\^$-1/, and 0.82∼7.32 ng g$\^$-1/, respectively. Relatively high PCB concentrations in both environmental matrices are found at the inner bay than the outer part, indicating that the sources of PCBs were located inside the bay. DDT compound showed relatively high concentrations in the vicinity of the mouth of river and urban area, whereas other organochlorine pesticides show homogeneous distributions over the bay. Homologue profile of PCB compounds shows that low-chlorinated congeners (especially, di-, tyi- and tetra-) are abundant in Gwangynng Bay, which is diferent from other areas in Korea.

• Journal of Conservation Science
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• v.37 no.5
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• pp.545-556
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• 2021

In this study, we aimed to elucidate the materialistic characteristics of 11 pieces of earthenware belonging to the Neolithic and Bronze Age excavated from Jeongseon Auraji, South Korea. As a result, the chemical composition of earthenwares belonging to the early Bronze Age was distributed in the intermediate area between the Neolithic and Bronze Age earthenwares, but no significant difference was confirmed based on their manufacturing period. Upon comparison, the earthenwares excavated from Jeongseon Auraji site were found to comprise less acidic components than those excavated from Yeongdong, and are characterized by the alkaline components depending on the excavated site. In the rare earth elements distribution pattern, all the analyzed earthenwares exhibited similar pattern, confirming that the raw materials present in the clay were the same. As a result of microstructure analysis, the clay particles and voids were found to be irregularly distributed in the analyzed earthenwares. Neolithic earthenwares exhibited many irregular voids, and an arrangement of aluminosilicate, including feldspar, was observed along with the clay substrate. Furthermore, we confirmed that the empty space in early Bronze Age earthenwares was filled with fine particles and cube crystals. Moreover, the main mineral phase of earthenwares excavated from Jeongseon Auraji exhibited similar composition, and therefore, there was no significant difference in the firing temperature of these earthenwares. The firing temperature of the earthenwares ranged from 750 to 850℃.

• Journal of the Korean Association of Geographic Information Studies
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• v.26 no.4
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• pp.173-187
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• 2023

In an era of population decline, depopulated regions facing challenges in attracting inbound population migration must enhance urban vitality through the attraction of living populations. This study focuses on Busan, a city experiencing population decline, comparing the spatiotemporal distribution characteristics of registered residents and living populations in various administrative districts (Eup-Myeon-Dong) using mobile communication big data. Administrative districts are typified based on population change patterns, and regional characteristics are analyzed using indicators related to urban decline and vitality. Spatiotemporal distribution analysis reveals generally similar density patterns between registered residents and living populations; however, a distinctive feature is observed in the city center areas where the density of registered residents is low, while the density of living populations is high. Divergent trends in spatial patterns of change between registered residents and living populations show clusters of registered population decline in low-density areas and clusters of living population decline in high-density areas. Areas adjacent to declining living populations exhibit large clusters of population changes, indicating a spillover effect from high-density to neighboring areas. Typification results reveal that, even in areas with a decline in registered residents, there is active population influx due to commuting or visiting. These areas sustain an increase in the number of businesses, confirming the presence of industrial and economic growth. However, approximately 47% of administrative districts in Busan are experiencing a decline in both registered residents and living populations, indicating ongoing regional decline. Urgent measures are needed for enhancing urban vitality. The study emphasizes the necessity of utilizing living population data as an urban planning indicator, considering the increasing limit distance of urban activities and growing interregional interaction due to advancements in transportation and communication.

• Journal of Korean Society of Transportation
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• v.33 no.4
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• pp.393-404
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• 2015

Gravity model has had the major problem that the model explains the characteristics of travel behavior with only deterrence factors such as travel time or cost. In modern society, travel behavior can be affected not only deterrence factors but also zonal characteristics or transportation service. Therefore, those features have to be considered to estimate the future travel demand accurately. In this regard, there are two primary aims of this study: 1. to identify the characteristics of inter-zonal travel, 2. to develop the new type of calibration method. By employing accessibility variable which can explain the manifold pattern of trip, we define the zonal travel behavior newly. Furthermore, we suggest 2-phase calibration method, since existing calibration method cannot find the optimum solution when organizing the deterrence function with the new variables. The new method proceeds with 2 steps; step 1.estimating deterrence parameter, step 2. finding balancing factors. The validation results with RMSE, E-norm, C.R show that this study model explains the inter-zonal travel pattern adequately and estimate the O/D pairs precisely than existing gravity model. Especially, the problem with estimation of short distance trip is overcomed. In conclusion, it is possible to draw the conclusion that this study suggests the possibility of improvement for trip distribution model.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.336-336
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• 2015

일반적인 다목적댐은 홍수 발생 시 본댐으로 유입되는 부유쓰레기 및 잡목 등을 차단하기 위하여 댐 상류에 차단망을 설치하여 1차적으로 사전 방지하고, 홍수기 이후 선박으로 부유물을 수거하여 재활용, 소각 등으로 처리하는 시스템이다. 그러나 본 연구의 대상인 한탄강댐은 홍수조절용 댐으로서 수위 변화 폭이 매우 크고 정상 조건(비 홍수기)시는 대규모 홍수터가 드러나기 때문에 댐 유지관리 방법이 상이하며 한탄강 본류 구간은 하폭과 수심 등 하도의 불규칙성과 만곡부에서 유수의 흐름이 한쪽으로 쏠리는 편기 현상이 발생하는 등 복잡한 수리현상으로 인하여 부유쓰레기의 분포를 판단하기 어려운 지역이다. 따라서 본 연구에서는 부유쓰레기의 유동을 모의하기 위하여 HEC-HMS 모형과 $Vflo^{TM}$ 모형을 활용하여 본류와 지류의 빈도별 홍수량 분석을 실시하고, EFDC 3차원 동수역학 모형을 적용하여 홍수조절용지 내 부유쓰레기의 유입 경로 및 정체 구역을 분석하여 효과적인 쓰레기 처리 방안을 제시하고자 하였다. 분석 결과, 소규모 빈도 홍수(2년, 5년)의 경우 중 상류 지류의 부유쓰레기는 거의 유동하지 못하고 하도의 만곡의 영향을 받아 부분적으로 높은 밀도로 고착될 것으로 모의되며, 특히 본류와의 합류점 부근에 도달한 부유쓰레기는 유로 폭이 급확대되어 유속이 거의 없는 사수역 구간으로 변함에 따라 본류 배수위 영향으로 불규칙하게 맴돌다가 고착되는 것으로 모의되었다. 중규모 홍수(25년, 50년)의 경우, 상류부의 부유쓰레기의 분포는 소규모 홍수 시와 유사한 패턴을 보였으나 중류부에서 홍수파가 본류 하도를 월류하여 홍수터로 넓게 범람하는 지역에서는 소규모 홍수 시 본류 하도 양안에 분포하던 부유쓰레기가 홍수터 쪽으로 밀려가서 고착되는 경향을 보였다. 대규모 홍수(100년, 200년)의 경우, 댐과 인접한 분석 구간 하류부는 댐 배수위의 영향을 가장 크게 받으며 수심이 깊어 흐름이 가장 정체되는 구간으로 본류와 지류 모두 다량의 부유쓰레기가 분포할 것으로 분석되었다. 분석 구간 중류부는 홍수 규모가 증가함에 따라 넓은 홍수터로 침수범위가 급격하게 증가하며 이에 따라 부유쓰레기가 분포할 수 있는 면적이 크게 증가할 것으로 분석되었다. 또한 분석 구간 상류부는 협곡을 이루고 있어 홍수규모가 증가하더라도 침수범위와 부유쓰레기의 분포면적에 큰 변화가 없을 것으로 분석되었다. 본 연구 결과를 바탕으로 댐의 치수 문제가 발생하지 않도록 효과적으로 수거 처리 할 수 있는 부유쓰레기 적치장 및 차단 시설의 적정 설치 위치를 파악하였다.

• Journal of Broadcast Engineering
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• v.16 no.4
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• pp.573-583
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• 2011

In this paper, we propose an occlusion compensation algorithm which is used for virtual view generation. In general, since occlusion region is recovered from neighboring pixels by taking the mean value or median value of neighbor pixels, the visual characteristics of a given image are not considered and consequently the accuracy of the compensated occlusion regions is not guaranteed. To solve these problem, we propose an algorithm that considers primary visual characteristics of a given image to compensate the occluded regions by using seam carving algorithm. In the proposed algorithm, we first use Sobel mask to obtain the edge map of a given image and then make it binary digit 0 or 1 and finally thinning process follows. Then, the energy patterns of original and thinned edge map obtained by the modified seam carving method are used to compensate the occlusion regions. Through experiments with many test images, we verify that the proposed algorithm performed better than conventional algorithms.