• Title/Summary/Keyword: 피해저감

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Prediction of Land Surface Temperature by Land Cover Type in Urban Area (도시지역에서 토지피복 유형별 지표면 온도 예측 분석)

  • Kim, Geunhan
    • Korean Journal of Remote Sensing
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    • v.37 no.6_3
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    • pp.1975-1984
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    • 2021
  • Urban expansion results in raising the temperature in the city, which can cause social, economic and physical damage. In order to prevent the urban heat island and reduce the urban land surface temperature, it is important to quantify the cooling effect of the features of the urban space. Therefore, in order to understand the relationship between each object of land cover and the land surface temperature in Seoul, the land cover map was classified into 6 classes. And the correlation and multiple regression analysis between land surface temperature and the area of objects, perimeter/area, and normalized difference vegetation index was analyzed. As a result of the analysis, the normalized difference vegetation index showed a high correlation with the land surface temperature. Also, in multiple regression analysis, the normalized difference vegetation index exerted a higher influence on the land surface temperature prediction than other coefficients. However, the explanatory power of the derived models as a result of multiple regression analysis was low. In the future, if continuous monitoring is performed using high-resolution MIR Image from KOMPSAT-3A, it will be possible to improve the explanatory power of the model. By utilizing the relationship between such various land cover types considering vegetation vitality of green areas with that of land surface temperature within urban spaces for urban planning, it is expected to contribute in reducing the land surface temperature in urban spaces.

A Study on Improvement of Hydrologic Cycle by Selection of LID Technology Application Area -in Oncheon Stream Basin- (LID 기술 적용 지역 선정에 따른 물순환 개선 연구 -온천천 유역을 대상으로-)

  • Kim, Jae-Moon;Baek, Jong-Seok;Shin, Hyun-Suk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.4
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    • pp.545-553
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    • 2021
  • The frequency by water disaster in urban areas are increasing continuously due to climate change and urbanization. Countermeasures are being conducted to reduce the damage caused by water disasters. An analysis based on permeability, one of the parameters that affect runoff, is needed to predict quantitative runoff in urban watersheds and study runoff reduction. In this study, the SWAT model was simulated for the oncheon stream basin, a representative urban stream in Busan. The permeability map was prepared by calculating the CN values for each hydrologic response unit. Based on the permeability map prepared, EPA SWMM analyzed the effect of LID technology application on the water cycle in the basin for short-term rainfall events. The LID element technology applied to the oncheon stream basin was rooftop greening in the residential complex, and waterproof packaging was installed on the road. The land cover status of the land selected based on the permeability map and the application of LID technology reduced the outflow rate, peak flow rate, and outflow rate and increased the infiltration. Hence, LID technology has a positive effect on the water cycle in an urban basin.

Analysis on inundation characteristics by compound external forces in coastal areas (연안 지역의 복합 외력에 의한 침수 특성 분석)

  • Kang, Taeuk;Sun, Dongkyun;Lee, Sangho
    • Journal of Korea Water Resources Association
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    • v.54 no.7
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    • pp.463-474
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    • 2021
  • The various external forces can cause inundation in coastal areas. This study is to analyze regional characteristics caused by single or compound external forces that can occur in coastal areas. Storm surge (tide level and wave overtopping) and rainfall were considered as the external forces in this study. The inundation analysis were applied to four coastal areas, located on the west and south coast in Republic of Korea. XP-SWMM was used to simulate rainfall-runoff phenomena and 2D ground surface inundation for watershed. A coupled model of ADCIRC and SWAN (ADCSWAN) was used to analyze tide level by storm surge and the FLOW-3D model was used to estimate wave overtopping. As a result of using a single external force, the inundation influence due to storm surge in most of the coastal areas was greater than rainfall. The results of using compound external forces were quite similar to those combined using one external force independently. However, a case of considering compound external forces sometimes created new inundation areas that didn't appear when considering only a single external force. The analysis considering compound external forces was required to reduce inundation damage in these areas.

Determination of Volume Porosity and Permeability of Drainage Layer in Rainwater Drainage System Using 3-D Numerical Method (3차원 수치해석기법을 이용한 우수배수시스템 배수층의 체적공극과 투수도 결정)

  • Yeom, Seong Il;Park, Sung Won;Ahn, Jungkyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.8
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    • pp.449-455
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    • 2019
  • The increase in impermeable pavement from recent urbanization has resulted in an increase in surface runoff. The surface runoff has also increased the burden of the existing drainage system. This drainage system has structural limitations in that the catchment area is reduced by the waste particles transported with the surface runoff. In addition, the efficiency of the drainage system is decreased. To overcome these limitations, a new type of drainage system with a drainage layer was developed and applied. In this study, various volume porosity and permeability of the lower drainage layer were simulated using ANSYS CFX, which is a three dimensional computational fluid dynamics program. The results showed that the outlet velocity of the 35% volume porosity was faster than that of the 20% and 50% cases, and there was no relationship between the volume porosity and drainage performance. The permeability of the drainage layer can be determined from the particle size of the material, and a simulation of five conditions showed that 2 mm sand grains are most suitable for workability and usability. This study suggests appropriate values of the volume porosity and particle size of the drainage layer. This consideration can be advantageous for reducing and preventing flood damage.

Disaster risk predicted by the Topographic Position and Landforms Analysis of Mountainous Watersheds (산지유역의 지형위치 및 지형분석을 통한 재해 위험도 예측)

  • Oh, Chae-Yeon;Jun, Kye-Won
    • Journal of Korean Society of Disaster and Security
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    • v.11 no.2
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    • pp.1-8
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    • 2018
  • Extreme climate phenomena are occurring around the world caused by global climate change. The heavy rains exceeds the previous record of highest rainfall. In particular, as flash floods generate heavy rainfall on the mountains over a relatively a short period of time, the likelihood of landslides increases. Gangwon region is especially suffered by landslide damages, because the most of the part is mountainous, steep, and having shallow soil. Therefore, in this study, is to predict the risk of disasters by applying topographic classification techniques and landslide risk prediction techniques to mountain watersheds. Classify the hazardous area by calculating the topographic position index (TPI) as a topographic classification technique. The SINMAP method, one of the earth rock predictors, was used to predict possible areas of a landslide. Using the SINMAP method, we predicted the area where the mountainous disaster can occur. As a result, the topographic classification technique classified more than 63% of the total watershed into open slope and upper slope. In the SINMAP analysis, about 58% of the total watershed was analyzed as a hazard area. Due to recent developments, measures to reduce mountain disasters are urgently needed. Stability measures should be established for hazard zone.

A Methodology to Evaluate Economic Feasibility by Taking into Account Social Costs from Automobile Exhaust Gases (자동차 배기가스로 인한 사회적 비용을 고려한 경제성 평가 방법론)

  • Cho, A-Ra;Lim, Seong-Rin
    • Clean Technology
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    • v.25 no.3
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    • pp.263-272
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    • 2019
  • Air pollutants have a high impact on everyday life as well as on human health; therefore, new technologies such as low-emission vehicles and add-on systems for air pollutant reduction are needed for our society. However, the environmental benefits and costs of those technologies are not taken into account in existing economic feasibility assessments, which is a barrier that needs to be overcome for green technology to achieve wide dissemination and fast penetration in the market. Thus, this study develops a methodology to assess the economic feasibility of an air pollutant reduction technology by taking into account the social costs from air pollutants and carries out a case study to validate the methodology. Because the social unit costs for air pollutants have not been evaluated yet in South Korea, the methodology uses the social unit costs evaluated for the European Union that are then converted to those for South Korea based on the measuring criteria for vehicle emission gases, parity purchasing price, foreign currency exchange rate, and customer price index. The social unit costs for South Korea are used to assess economic feasibility. A case study was performed to assess the economic feasibility of a dual fuel system using diesel and compressed natural gas by taking into account social costs from air pollutants as well as economic costs. This study could contribute to assessing the true economic feasibility of green technology, projects, and policy related with air pollutant reduction.

An Experimental Study on Ground Reinforcement Effect of Concrete and Expansion Mat for Prevention of Buried Pipe Damage (지중매설관 손상 방지를 위한 콘크리트매트와 팽창매트의 지반보강효과에 관한 실험적 연구)

  • Park, Jeong-Jun;Shin, Heesoo;Yuu, Jungjo;Hong, Gigwon
    • Journal of the Korean Geosynthetics Society
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    • v.18 no.1
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    • pp.91-101
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    • 2019
  • Recently, small-scale excavation like ground cavity restoration and buried pipe replacement works are being carried out in urban area, in order to improve living convenience. This paper describes experiment results on the ground reinforcement method that can reduce the buried pipe damage, when the differential settlement occurred due to poor compaction of ground below the buried pipe. Plate load tests were conducted to evaluate a reinforcement effect of ground using concrete mat and expansion mat in the ground below the buried pipe. The results showed that the stress reduction ratio by concrete mat and expansion mat according to the surcharge load was about 46%~48% and 39%~42%, respectively. Therefore, the differential settlement of the buried pipe and the ground deformation below the buried pipes were reduced by the reinforcement effect of the concrete mat and expansion mat. This means that it is possible to prevent a buried pipe damage due to underground cavity and ground subsidence, if concrete mat and expansion mat are reinforced in the ground below the buried pipe or on the ground between the buried pipes.

A Study on the Selection of Types of Social Disasters by Region (시·도별 사회재난 중점유형 선정에 관한 연구)

  • Lee, Hyo Jin;Yun, Hong Sic;Han, Hak
    • Journal of the Society of Disaster Information
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    • v.17 no.2
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    • pp.206-217
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    • 2021
  • Purpose: Recently, a series of large social disasters have led to a lot of research to prevent social disasters as well as natural disasters and reduce damage. However, this paper aims to select the types of social disasters that local governments should focus on and create basic data for effective countermeasures and mitigation efforts. Method: Among 43 types of disasters announced by the Ministry of Public Administration and Security, 11 types of disasters were selected and collected to select the main types of disasters, and risk types were derived by region with risk maps. In order to derive the risk map, each detailed index was rescheduled to be 0-1 and weights were determined through entropy technique. Result: As a result, about 41% of the major disasters announced by the Ministry of Public Administration and Security were consistent, and the rest of the major types were disasters that could not be obtained or have not occurred in the past 20 years. Conclusion: Therefore, in order to establish an effective prevention and recovery plan for social disasters through this study, it was intended to present social disaster-focused disasters for each local government.

Degradation Assessment of Forest Trails in Gyeongnam Domain of Mt. Jiri (지리산 숲길 경남권역 구간의 훼손 실태 평가)

  • Park, Jae-Hyeon;Huh, Keun-Young;Lim, Hong-geun
    • Journal of Korean Society of Forest Science
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    • v.100 no.3
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    • pp.476-482
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    • 2011
  • As part of studies on the reduction of forest trails degradation caused by high users density, this study was carried out to investigate soil physical properties of forest trails of Gyeongnam Domain in Mt. Jiri, Southeast Korea. Since the forest were opened for leisure trailing in 2008, the average soil erosion amounts per a square meter on the forest trails were $0.0015m^3$ from Inweol to Gumgeo, $0.0018m^3$ from Dongang to Suchol, and $0.0027m^3$ from Suchol to Chungam for 3 years. But, from Chungam to Agyang, the erosion was almost not occurred because it was recently opened. The soil hardness in 5 cm depth was significantly higher than in 10 cm depth. It indicates that intensive soil compaction by users has mainly affected in 5 cm soil depth until now on. In three forest trails compacted intensively, the porosity of 0-7.5 cm soil layer was down to 1.4-1.5 times compared to that in 2008. In additions, the bulk density was up to 1.6-3.1 times compared to the controls, which were not opened to users. As a result, the degradation caused by high users density would keep occurring on the three forest trails unless any counterplans are considered for the degradation reduction. At the moment, users distribution to other forest trails and long-term sabbatical years would be the most effective counterplans to keep from users gravitation on the three forest trails.

Design of Marine IoT Wireless Network for Building Fishing Gear Monitoring System (어구 모니터링 시스템 구축을 위한 해상 IoT 무선망 설계)

  • Kwak, Jae-Min;Kim, Se-Hoon;Lee, Seong-Real
    • Journal of Advanced Navigation Technology
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    • v.22 no.2
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    • pp.76-83
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    • 2018
  • In order to prevent overusing the fishing gear and to reduce discarded fishing gear, there is a need for a technique that can efficiently transmit the information including the type and location of the fishing gear and the user's real name to the fishing boat and the control center using IoT-based communication. In order to do this, it is necessary to be able to confirm the position information of a plurality of buoys that can be identified by the base stations on the land. In this paper, in order to service the maritime IoT communication system, we calculate the link budget between the land base station and the targets on the sea to derive the service coverage. To design a marine IoT radio network for building a fishing gear monitoring system, we calculate link budget for wireless service optimization at sea for NB-IoT using 1.8 GHz frequency band and LoRa service using 900 MHz frequency band. In addition, the link budget between the land base station and buoy, the link budget between the land base station and fishing boat are calculated and the results are analyzed.