• Journal of Korean Society of Disaster and Security
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• v.9 no.2
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• pp.87-91
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• 2016

In recent years, lots of damages appear frequently due to cyber terrorism and natural disasters such as typhoon 'Chaba', earthquake at Kyeongju. The damages lead to people's anxiety and public institutions connected directly with them also can't be free from the threat situation. In addition, public institutions must prepare business continuity issues with the highest priority in the event of disasters because they are closest with people's safety. However, preceding researches suggest needs of disaster mitigation activities management system or central office oriented top-down BCP establishing system. In this study, We grasp the current status of public institutions's business continuity plan(BCP) against disaster and we propose an efficient bottom-up method for structuring the BCP of public institutions.

• Journal of Korean Society of Transportation
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• v.22 no.5
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• pp.75-87
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• 2004

Along the seashore regions in Korea, though strong winds with very large strength are frequently witnessed, no system which can provide appropriate speed information for driving vehicle has been introduced. The driving against strong winds could be very dangerous because of the high possibility of accidents such as rollover and collision. These accidents usually resulted from driver's forced driving try even in difficult situation for steering vehicle, and sometimes overspeed without consideration of wind impact to the vehicles. To reduce accident caused by strong winds, it is important to inform drivers of appropriate driving speeds by perceiving strong winds. By setting up WIS at the main points where strong winds frequently appear and using the variable message sign(VMS) connected to the on-line whether information system, it tis possible to provide desired speed information, which can maintain vehicles' tractive force and maximum running resistance. The case study is conducted on the case of Mokpo-Big-Bridge, which is under construction at Mokpo city. The result show that in case the annual average direction of wind is South and the wind speed is over 8m/hr, the desired speed, which is required in order for vehicles running to South direction to maintain the marginal driving power, is 60km/hr. In addition, for the case of a typhoon such as Memi generated in 2003 year, if wind speed had been 18m/sec in Mokpo city at that time, the running resistance at the speed of 40km/hr is calculated as 1131N. This resistance can not be overcome at the 4th gear(1054N) level, therefore, the gear of vehicles should be reduced down to the 3rd level. In this case, the appropriate speed is 40km/h, and at this point the biggest difference between running resistance and tractive force is generated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.5151-5156
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• 2010

In the previous researches for storm sewer design, the flow paths in overall network were determined to minimize the construction cost and then, it was not considered the superposition effect of runoff hydrographs in the sewer pipes. However, in this research, the flow paths are determined considering the superposition effect to reduce the inundation risk by controlling and distributing the flows in the sewer pipes. This is accomplished by distributing the inflows that enter into each junction by changing the flow path in which pipes are connected between junctions. In this paper, the superposition effect and peak outflows at outlet were analyzed considering the changes of the flow paths in the sewer network. Then, the flow paths are determined using genetic algorithm and the objective function is to minimize the peak outflow at outlet. As the applied result for the sample sewer network, the difference between maximum and minimum peak outflows which are caused by the change of flow path was about 5.6% for the design rainfall event of 10 years frequency with 30 min. duration. Also, the typhoon 'Rusa' which occurred at 2002 was applied to verify the reduction of inundation risk for the excessive rainfall, and then, the amount of overflows was reduced to about 31%.

• Journal of Korea Port Economic Association
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• v.29 no.4
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• pp.289-323
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• 2013

This study set out to estimate and compare benefits of damage in case of storm surge at the Masan Port by using two of the most representative methodologies used to estimate benefits in port disaster prevention facility construction, namely CVM(contingent valuation method), which estimates the values of non-market goods, and MD-FDA(multi-dimensional flood damage analysis), which had usually been implemented in flood or dam projects. The benefit estimation for 30 years of costs was 2.5689 trillion won for CVM and 2.9596 trillion won for MD-FDA, which indicates that there was no big difference in benefits among disaster prevention facilities. However, in-depth testing should follow to figure out whether MD-FDA can replace CVM, which has been tested with non-market goods, when estimating the benefits of disaster prevention facilities based on those findings.

• Korean journal of communication and information
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• v.70
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• pp.246-276
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• 2015

From a historical perspective of risk communication, risks can be classified by their associated level of responsibility. In the case of technical risks such as hazardous chemical accidents, people perceive that risk-related organizations have a high level of responsibility; however, they do not in traditional risks such as natural disasters. This study aims to examine risk information seeking and processing, as seen in two types of risk, based on the Risk Information Seeking and Processing(RISP) model. For this purpose, hypotheses and a research question are developed with current domestic risk issues, and the results show significant differences in risk information seeking and processing between the two types of risk. Specifically, in the case of the chemical spill accident, negative emotion against relevant institutions makes different information seeking and processing compared to the natural disaster. The low level responsibility risk such as typhoon comparatively follows the flow of the original RISP model. However, the high level responsibility risk such as the hydrofluoric acid spill did not match with the RISP model. Based on the research results, theoretical implications were discussed.

• Journal of Korea Water Resources Association
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• v.37 no.9
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• pp.707-718
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• 2004

This study is to analyze the Probable Maximum Flood(PMF) as a part of counterplan for the disaster prevention of hydraulic structures such as dams, according to recent unfavorable weather conditions. During the period of typhoon RUSA in August 2002, the rainfall recorded in Gang-loeng Province was 880mm a day and exceeded the scale of PMP made in 2001. Accordingly, the reconsideration of hydrologic criteria for dam design was inevitable. In the design of dams for flood controls, the design flood must be determined by introducing the concept of maximum values. When the duration of design rainfall is determined, it needs to use the critical duration which causes the maximum flood by the maximum runoff. In this study, we Investigate the variation of critical duration with hydrologic parameters used in three different synthetic unit hydrographs(Clark, Nakayasu and SCS methods). As a result, the total runoff calculated from 24-hour duration is larger than that calculated from the critical duration. We calculate also the hydrographs with three different time distribution models(Huff's 4-quartile, IDF curve and Mononobe) and compare those with measured hydrograph data. From this comparison, we propose that the Huff's 4-quartile model must be used to obtain the desirable data in the hydrologic design of dams.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.296-296
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• 2008

국내 절토비탈면은 이상 기후 및 건설공사의 증대로 인해 증가하고 있는 추세이며 장마철 및 태풍으로 인해 비탈면의 붕괴로 많은 인명 및 재산피해가 발생되고 있는 실정이다. 국내에서 사용되고 있는 기존의 비탈면의 설계기준은 암반의 불연속면에 대한 조사를 실시하고는 있지만 주로 암반의 굴착난이도를 토층, 리핑암, 발파암으로 구분하여 각각의 비탈면 절취경사를 결정하여 사용하는 방법을 사용하였으며 이러한 기준은 단순히 암석의 강도를 기준으로 설정되어 있으므로 암석의 공학적 특성 즉, 암반내 불연속면 방향성, 연속성, 충진물질, 마찰각, 풍화속도 등의 영향으로 공용후 비탈면 구배의 재조정 및 보강이 빈번하다. 국내외 절토비탈면의 설계기준은 각 기관별로 산재되어 있었으며 비탈면에 대한 설계 및 시공 등에 관한 기준은 도로와 철도 설계기준에 일부 반영되어 있을 뿐 항만, 댐, 택지조성 등 기타 시설 설계기준에는 비탈면에 대한 기준이 마련되어 있지 않아 표준적인 비탈면 설계기준 및 유지관리지침이 등이 필요하였다. 이러한 문제점을 보완하기 위해 2004년부터 2006까지 한국시설안전공단, 한국도로공사, 대한주택공사가 협동으로 연구한 건설공사 비탈면 설계 시공 및 유지관리에 관한 연구의 결과로 2006년도에 "건설공사 비탈면 설계기준"이 수립되었다. 이 설계기준은 건설공사에서의 기존 상이한 기준들을 정리하고 동일화하는 작업을 수행하였으며 지반의 조사에서부터 대책공까지를 막나하여 정리하였다. 그러나 최근에 급격한 기후변화로 인한 비탈면붕괴 빈번함에 따라 과거 적용되어 왔던 이들 기준을 적용하는 경우, 특히 상부 토층 및 풍화암 구간에서 많은 설계안전율을 만족하지 못해 많은 보강을 수반해야 하는 문제가 발생되고 있어 그 원인에 대한 분석을 수행하고자 하였다. 2006년도 정리된 기준은 과거에 적용하여 온 유기시의 안전율 조건을 Fs > 1.1~1.2을 적용하였던 것을 Fs > 1.2로 통일하였으며 지하수위 조건은 지표면에 위치하도록 하였다. 지하수위 조건은 풍화암 및 토층의 경우, 과거 지표면에 -3m를 적용한 시기가 있었으나 지표면에 지하수위를 적용하는 것이 일반적인 해석방법이다. 이러한 결과의 원인을 검토해 보면 다음과 같다. 첫째, 풍화암 및 토층에 적용되어 온 지반강도 정수가 과거 적용한 값보다 최근에는 작아지는 경향을 보이고 있다. 둘째, 지하수위 적용문제로 현재 지표면에 지하수위를 두어 안전율을 감소시키는 문제로 이는 최근 들어 많은 연구기관에서 강우시 간극수압의 증가에 대한 연구가 활발하게 진행되고 있다. 그러나 침투수 해석은 현행 기준에도 강우의 침투를 고려한 해석을 실시하는 경우 FS > 1.3 적용하는 것으로 되어 있으나 대부분의 해석에서는 적용이 되지 못하고 있는 실정이다. 셋째, 안전율이 과거에 주로 적용된 Fs > 1.1에서 Fs > 1.2로 상향 조정되어 우기시의 설계안전율 만족시키지 못하는 문제이다. 그러므로 이러한 문제점을 개선하기 위한 검토가 필요하며 장기적으로 이에 대한 합리적인 기준을 개정하는 작업이 추후에 수행되어야 할 것으로 판단된다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.1
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• pp.10-18
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• 2018

Recently, a port city has been gradually expanding near coastal area, and many facilities for tourism and waterfront have been constructed near the shore. When storm surge developed by typhoon have occurred, coastal facilities have a lot of damage and failure with loss of life caused directly by the waves. Various barriers have been suggested to protect property and human life from disasters, they have not been widely applied though. Because they do not satisfy the recent trends that emphasize the surrounding scenery. In this study, a moveable barrier on revetment is proposed against wave overtopping. This moveable barrier has two function, sightseeing and protecting. In case of usual day, it is installed on the revetment and used observatory deck for sightseeing. When wave overtopping has occurred by storm surge, it protect coastal area through changing of flat deck to triangular barrier. The hydraulic and the structural performance of the newly proposed movable barrier was investigated through numerical analysis using commercial program. As a results, this structure has numerically good performance, and follow-up research is required through experimental tests though.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.917-926
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• 2021

Lodging rice is one of critical agro-meteorological disasters. In this study, the UAV-based multispectral imageries before and after rice lodging in rice paddy field of Jeollanamdo agricultural research and extension servicesin 2020 was analyzed. The UAV imagery on 14th Aug. includesthe paddy rice without any damage. However, 4th and 19th Sep. showed the area of rice lodging. Multispectral camera of 10 bands from 444 nm to 842 nm was used. At the area of restoration work against lodging rice, the reflectance from 531 nm to 842 nm were decreased in comparison to un-lodging rice. At the area of lodging rice, the reflectance of around 668 nm had small increases. Further, the blue and NIR (Near-Infrared) wavelength had larger. However, according to the types of lodging, the change of reflectance was different. The NDVI (Normalized Difference Vegetation Index) and NDRE (Normalized Difference Red Edge) shows dome sensitivities to lodging rice, but they were different to types of lodging. These results will be useful to make algorithm to detect the area of lodging rice using a UAV.

• Journal of the Korean GEO-environmental Society
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• v.20 no.5
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• pp.5-12
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• 2019

On November 15, 2017, a unpredictable liquefaction damage was occurred at the $M_L=5.4$ Pohang earthquake and after, many researches have been conducted in Korea. In Korea, where there were no cases of earthquake damage, it has been extremely neglectable in preparing earthquake risk maps and building earthquake systems that corresponded to prevention and preparation. Since it is almost impossible to observe signs and symptoms of drought, floods, and typhoons in advance, it is very effective to predict the impacts and magnitudes of seismic events. In this study, 14,040 borehole data were collected in the metropolitan area and liquefaction evaluation was performed using the amplification factor. Based on this data, liquefaction hazard maps were prepared for ground accelerations of 0.06 g, 0.14 g, 0.22 g, and 0.30 g, including 200years return period to 4,800years return period. Also, the correlation analysis between the earthquake acceleration and LPI was carried out to draw a real-time predictable liquefaction hazard map. As a result, 707 correlation equations in every cells in GIS map were proposed. Finally, the simulation for liquefaction risk mapping against artificial earthquake was performed in the metropolitan area using the proposed correlation equations.