• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.640-640
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• 2015

2010년과 2011년 서울에서 발생한 집중호우와 2014년 부산에서 발생한 집중호우의 발생으로 막대한 재산상의 피해와 사상자를 냈다. 2010년 9월 21일에 발생한 집중호우는 1908년 관측시작이래 가장 많은 비가 내린 것으로 기록되었으며 주거지 4,727호, 상가 1,164호, 공장 126동 등이 침수되고 13시를 기준으로 강서지점의 경우 시간당 98.5mm의 기록적인 강우를 기록하였으나, 관악지점은 5.5mm에 그쳐 두 지점간의 시간당 강우량의 편차가 약 200배 가까이 차이가 나는 것으로 나타났다. 이와 같이 최근 도시지역에서 국지성 집중호우가 증가하고 있으며 지역별 강우 편차가 크고 이에 따라 침수피해발생 여부도 지역에 따라 달라진다. 강수의 공간적 분포와 그로 인한 침수해석은 도시돌발홍수 예경보 시스템에 있어 무엇보다도 중요하다. 본 연구의 목적은 도시지역 돌발홍수 예경보 시스템 구축을 위한 정량적 강수추정 QPE(Quantitative Precipitation Estimation)기법에 따른 수리 수문학적 영향을 평가하는 것이다. 정량적 강수추정을 위해 AWS, SKP, 레이더 자료를 활용하여 250m의 해상도를 가지도록 크리깅을 적용하였다: QPE 1은 34개의 AWS의 지점우량을 지구통계학적 기법 중의 하나인 크리깅을 이용하여 산정한 기법, QPE 2는 AWS와 156개의 SKP의 강우데이터를 크리깅을 이용하여 산정한 기법, QPE 3는 광덕산 레이더를 이용한 기법, QPE 4는 AWS, SKP, 광덕산 레이더 자료를 조건부 합성한 기법이다. 월류량을 산정하기 위해 도시유출해석모형인 SWMM을 강남역 일대를 대상으로 구축하고 우수관로 시스템으로 유입되지 못한 노면류(Surface flow)를 함께 고려하였다. 침수해석을 위해서는 DHM모델을 적용하였으며 2013년 7월 기간에 발생한 호우에 대하여 분석을 수행하였다. 비교수행을 위해서 인접한 서초 AWS와 강남 AWS의 지점강우량도 함께 고려하였으며 모의결과를 국가 재난관리 정보 시스템(NMDS)에 침수피해가 확인된 가옥 및 빌딩 정보와 일치여부를 적합도로 산정하였다. 산정된 적합도를 통하여 정량적 강수추정기법에 따른 수리?수문학적 영향을 평가하였다. 실제 침수흔적정보와 비교 결과, QPE 2와 QPE4가 가장 적합도가 높았으며 이에 따라 고밀도의 관측망의 구성이 도시지역 침수해석결과에도 적합할 것으로 판단된다.

• Korean Journal of Remote Sensing
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• v.37 no.5_2
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• pp.1235-1243
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• 2021

Geostationary Ocean Color Imager 2 (GOCI-II) on Geo-KOMPSAT-2 (GK2B)satellite was developed as a mission successor of GOCI on COMS which had been operated for around 10 years since launch in 2010 to observe and monitor ocean color around Korean peninsula. GOCI-II on GK2B was successfully launched in February of 2020 to continue for detection, monitoring, quantification, and prediction of short/long term changes of coastal ocean environment for marine science research and application purpose. GOCI-II had already finished IAC and IOT including early in-orbit calibration and had been handed over to NOSC (National Ocean Satellite Center) in KHOA (Korea Hydrographic and Oceanographic Agency). Radiometric calibration was periodically conducted using on-board solar calibration system in GOCI-II. The final calibrated gain and offset were applied and validated during IOT. And three video parameter sets for one day and 12 video parameter sets for a year was selected and transferred to NOSC for normal operation. Star measurement-based INR (Image Navigation and Registration) navigation filtering and landmark measurement-based image geometric correction were applied to meet the all INR requirements. The GOCI2 INR software was validated through INR IOT. In this paper, status and results of IOT, radiometric calibration and INR of GOCI-II are analysed and described.

• The Journal of the Korea Contents Association
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• v.19 no.3
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• pp.114-125
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• 2019

The frequency of official injury of fire-fighting officers exposed to an extreme situation in disaster areas has been continuously increased. In spite of increase of injury, procedures of injury approval are complex, so the working environment of fire-fighting officers is very poor in terms of safety management. This study was, therefore, conducted to provide basic data for improvement of the injury management system for fire-fighting officers, by empirically analyzing the system for those in Busan city. The findings of the empirical analysis are as follows: first, the frequency of injury experienced by them is higher than that of other occupations; second, application for injury is not actively made; third, fire-fighting officers should bear the expense if injury is approved. On the basis of such an analysis on actual conditions, an analysis on policy factors for improving the injury management system shows; first, various high-risk matters should be considered in the review of application for injury, for improvement factors of the application for injury, while it is necessary to extend the benefit and support project for injured officers, for operation improvement factors of the injury management system, and the compensation act should be improved, for the improvement factors of the injury system. Second, it is urgent to develop damage prevention and coping education program for improving the injury management system. In addition, the simplification of administrative procedures of application for injury and the extension of benefit and support project for injured officers should be realized as soon as possible, moreover, the enhancement of directors' interest and support is also required.

• Journal of Internet Computing and Services
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• v.21 no.6
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• pp.1-12
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• 2020

Low-Orbit satellite mobile networks can provide services through miniaturized terminals with low transmission power, which can be used as reliable means of communication in the national public disaster network and defense sector. However, the high traffic environment in the emergency preparedness situation increases the new call blocking probability and the handover failure probability of the satellite network, and the increase of the handover failure probability affects the QoS because low orbit satellites move in orbit at a very high speed. Among the channel allocation methods of satellite communication, the FCA shows relatively better performance in a high traffic environment than DCA and is suitable for emergency preparedness situations, but in order to optimize QoS when traffic increases, the new call blocking and the handover failure must be minimized. In this paper, we propose LEO-DBC (LEO satellite dynamic beam width control) technique, which improves QoS by adaptive adjustment of beam width of low-orbit satellites and call time of terminals by improving FCA-QH method. Through the LEO-DBC technique, it is expected that the QoS of the mobile satellite communication network can be optimally maintained in high traffic environments in emergency preparedness situations.

• Journal of Korea Water Resources Association
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• v.53 no.12
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• pp.1193-1201
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• 2020

This study aims to develop a regression model that estimates a low-flow index that can be applied to ungauged basins. A total of 30 midsized basins in South Korea use long-term runoff data provided by the National Integrated Water Management System (NIWMS) to calculate average low-flow, average minimum streamflow, and low-flow index duration and frequency. This information is used in the correlation analysis with 18 basin factors and 3 climate change factors to identify the basin area, average basin altitude, average basin slope, water system density, runoff curve number, annual evapotranspiration, and annual precipitation in the low-flow index regression model. This study evaluates the model's accuracy by using the root-mean-square error (RMSE) and the mean absolute error (MAE) for 10 ungauged, verified basins and compares them with the previous model's low-flow calculations to determine the effectiveness of the newly developed model. Comparative analysis indicates that the new regression model produces average low-flow, attributed to the consideration of varied basin and hydrologic factors during the new model's development.

• Journal of Korea Water Resources Association
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• v.55 no.1
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• pp.85-97
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• 2022

In this study, a method for an integrated flood risk mapping was proposed that simultaneously considers the flood inundation map indicating the degree of risk and the disaster vulnerability index. This method creates a new disaster map that can be used in actual situations by providing various and specific information on a single map. In order to consider the human, social and economic factors in the disaster map, the study area was divided into exposure, vulnerability, responsiveness, and recovery factors. Then, 7 indicators for each factor were extracted using the GIS tool. The data extracted by each indicator was classified into grades 1 to 5, and the data was selected as a disaster vulnerability index and used for integrated risk mapping by factor. The risk map for each factor, which overlaps the flood inundatoin map and the disaster vulnerability index factor, was used to establish an evacuation plan by considering regional conditions including population, assets, and buildings. In addition, an integrated risk analysis method that considers risks while converting to a single vulnerability through standardization of the disaster vulnerability index was proposed. This is expected to contribute to the establishment of preparedness, response and recovery plans for providing detailed and diverse information that simultaneously considers the flood risk including social, humanistic, and economic factors.

• Journal of Korea Water Resources Association
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• v.55 no.1
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• pp.71-84
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• 2022

The objective of this study is to develop a two-dimensional (2D) flood model that can perform accurate flood analysis with simple input data. The 2D flood inundation models currently used to create flood forecast maps require complex input data and grid generation tools. This sometimes requires a lot of time and effort for flood modeling, and there may be difficulties in constructing input data depending on the situation. In order to compensate for these shortcomings, in this study, a grid-based model that can derive accurate and rapid flood analysis by reflecting correct topography as simple input data was developed. The calculation efficiency was improved by extending the existing 2×2 sub-grid model to a 5×5. In order to examine the accuracy and applicability of the model, it was applied to the Gamcheon Basin where both urban and river flooding occurred due to Typhoon Rusa. For efficient flood analysis according to user's selection, flood wave propagation patterns, accuracy and execution time according to grid size and number of sub-grids were investigated. The developed model is expected to be highly useful for flood disaster mapping as it can present the results of flooding analysis for various situations, from the flood inundation map showing accurate flooding to the flood risk map showing only approximate flooding.

• Journal of Cadastre & Land InformatiX
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• v.51 no.2
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• pp.5-20
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• 2021

With the available national spatial information that started from the sinkholes that occurred nationwide in 2014 and integrated 15 areas of underground information, the Underground Spatial Integrated Map has been continuously maintained since 2015. However, until recently, as disasters and accidents in underground spaces such as hot water pipes rupture, cable tunnel fires, and ground subsidence continue to occur, there is an increasing demand for quality improvement of underground information. Thus, this paper attempted to prepare a plan to improve the quality of the Underground Spatial Integrated Map data. In particular, among the 15 types of underground information managed through the Underground Spatial Integrated Map, quality validation improvement measures were proposed for underground facility (structure-type) data, which has the highest proportion of new constructions. To improve the current inspection methods that primarily rely on visual inspection, we elaborate on and subdivide the current quality inspection standards. Specifically, we present an approach for software-based automated inspection of databases, including graphics and attribute information, by adding three quality inspection items, namely, quality inspection methods, rules, and flow diagram, solvable error types, to the current four quality inspection items consisting of quality elements, sub-elements, detailed sub-elements, and quality inspection standards.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.613-621
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• 2021

This study conducted a network analysis to determine how COVID-19 vaccine-related issue spread on Twitter during the introduction stage of the COVID-19. Issue diffusion tendency is analyzed according to the time period: phase 1 (initiation of vaccine introduction: March 7 - April 3, 2021), phase 2 (stagnant period of vaccination: April 4 - April 22, 2021), and phase 3 (increase of vaccination: April 23 - May 5, 2021). NodeXL was used for data collection and analysis. Daily Twitter network data were collected by entering search terms highly related to the COVID-19 vaccine. This study found that side effects-related opinions were repeatedly formed throughout the analysis period. As the vaccination rate increased and death cases were reported on media, death-related issues also emerged on Twitter. On the other hand, vaccine safety did not receive much attention on Twitter. The results of this study highlight the role of social media as a channel of issue diffusion when a national disaster strikes. We emphasize the need for the government to monitor public opinions on social media and reflect them in crisis communication strategies.

• Journal of Korea Water Resources Association
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• v.55 no.12
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• pp.1137-1147
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• 2022

River and groundwater stages are the main elements in the hydrologic cycle. They are spatially correlated and can be used to evaluate hydrological and agricultural drought. Stochastic simulation is often performed independently on hydrological variables that are spatiotemporally correlated. In this setting, interdependency across mutual variables may not be maintained. This study proposes the Bayesian vector autoregression model (VAR) to capture the interdependency between multiple variables over time. VAR models systematically consider the lagged stages of each variable and the lagged values of the other variables. Further, an autoregressive model (AR) was built and compared with the VAR model. It was confirmed that the VAR model was more effective in reproducing observed interdependency (or cross-correlation) between river and ground stages, while the AR generally underestimated that of the observed.