• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.577-577
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• 2016

기후변화는 전 지구적 현상으로 이로 인한 홍수피해는 심화되고 있다. 기후변화 정부간 협의체 5차 보고서(IPCC, 2014)에 의하면 1980년대 이전 세계 평균 홍수피해액은 70억 달러 수준이었으나 2011년에는 240억 달러로 크게 증가한 것으로 나타났다. 2013년 필리핀에 태풍 '하이옌' 내습으로 인해 6,200여명이 사망하고, 2천여명이 실종되는 피해가 발생하였다. 국내의 경우 2014년 8월 경남 부산지역에는 시간당 130mm가 넘는 국지성 호우에 따라 차량 4,000여대가 침수, 5명 사망 등 약 125억원의 재산피해가 발생한 바 있다. 국회예산정책처(2012)와 소방방재청(2014)에 따르면, 자연재해 중 집중호우 및 태풍에 의한 호우피해가 85%를 차지하였으며, 전국 하천 피해액의 98.7%가 지방 및 소하천에서 발생하고 있다. 이에 따라 중소하천과 같이 소외된 지역의 물복지 향상을 위해서는 홍수재해 상황에 대하여 선제적 효과적 대응을 위한 과학적 체계적인 홍수통합관리 체계의 구축이 요구되고 있다. 특히 홍수관련 유관기관 자료를 연계한 실시간 상 하류 수문상황 모니터링, 홍수분석 및 하천수위별 대응기준 수립, 배수펌프장 등 수리시설원격 제어 등을 포함하는 홍수 통합관리체계 구축과 같은 비구조적 대책의 수립이 제방정비, 저류조 등 구조적 대책과 병행하여 반드시 추진되어야 한다. 이에 K-water는 ICT기반의 물관리기술력과 경험을 활용하여, 인력 기술력 예산 부족 등 열악한 재난관리 여건으로 어려움을 겪고 있는 지자체와 협업을 통해 홍수통합관리체계 구축을 지원하고 있다. 홍수통합관리체계 구축은 지자체 상 하류의 다양한 재난정보를 수집 통합하고, 수집된 정보를 활용한 홍수분석 및 홍수 대응기준 수립을 통해 예방적 재난대응 체계를 마련하는 것으로, K-water는 지난 2010년 남원시를 시작으로 무주군, 군산시, 진안군 등 21개 지자체의 홍수재해 통합관리체계 구축을 지원하고 있다. 특히 남원시의 경우 본 사업을 통한 시스템 구축후 홍수피해액이 50% 감소한 것으로 확인되는 등 재난관련 골든타임을 확보하고 홍수피해 최소화를 위한 홍수재해 통합관리 체계 구축은 이제 선택이 아닌 필수라 할 수 있다. K-water는 물관리 전문 공기업으로써의 역할을 다하고, 예방 중심의 재난관리 체계 마련을 위해 '지자체 맞춤형 홍수통합관리체계' 구축 지원을 지속적으로 확대해나갈 예정이다.

• International Area Studies Review
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• v.14 no.1
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• pp.55-76
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• 2010

This paper analyses interaction between yen/dollar exchange rates and NIKKEI index using bivariate GJR-GARCH(1,1) model. The data employed for the study is daily data series for the period of Jan. 4, 1995 through Aug. 30, 2009. One of main findings is that market inefficiency appears in the periods of financial crisis. Second, the volatility of exchange rates and stock returns has more increased in the wake of the volatility shock of the previous period during financial crisis than during non-financial crisis. Third, interestingly, the asymmetric volatility shock by bad news in those markets is bigger in financial crisis period than in non financial crisis. Fourth, in the period of current global financial crisis triggered by subprime mortgage crisis in U.S, volatility shock at the previous period is bigger than that of Asian financial crisis that happened in 1997. Lastly, the correlation between both returns of exchange rates and stock prices turns up positive according to the empirical estimation. This result may come from the fact that Japanese stock market does not have much attraction for international financial investment compared to stock markets of neighbouring countries like China, Korea and so on, while real sector's contribution to the economy is considered more importantly.

• The Journal of Engineering Geology
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• v.29 no.2
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• pp.99-112
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• 2019

Rainfall infiltration through the unsaturated zone is influenced by a range of factors including topography, geology, soil, rainfall intensity, temperature and vegetation; the actual infiltration varies largely in time and space. The infiltration capacity of soil is a critical factor in identifying groundwater recharge and leakage of surface water. It may differ depending on soil types and geological features of a particular basin or territory as well as on the usage of the land. This study was conducted in forest and farmland region of the mid-mountain area (EL. 50~300 m) of Jeju Island to test soil infiltration capacity of the area where rainfall contributes to groundwater. Results were analyzed using the four soil group classification methods presented by Jeong et al. (1995) and NAS (2007) to discover that the method offered by NAS (2007) is more reliable in the mid-mountain area of Jeju Island. The study compares and reviews the existing classification methods using the results of infiltration capacity tests executed on different soil groups throughout the whole region of the Jeju mid-mountain area. It is expected that this work will serve as a guideline for evaluating surface water recharge and hydraulic characteristics of Jeju Island.

• Korean Journal of Heritage: History & Science
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• v.51 no.2
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• pp.92-107
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• 2018

In 2013~2016, gilt-bronze shoes were excavated from the ancient tombs in Jeongchon Village located at Bogam-ri, Dasi-myeon in Naju. They are estimated to have been made in the late 5th or early 6th centuries. The gilt-bronze shoes are significant in that they serve to explicate the relationship between the center of Baekje and the local forces in the Yeongsan River Basin. This study's specific focus was the gilt-bronze shoes from the ancient tombs in Jeongchon Village. Based on the findings, a restoration drawing was designed and restored products were manufactured by considering metalwork techniques used to manufacture the original ones. At first, manufacturing techniques were tested by using a scientific analysis and visual observation. The manufacturing method, structures, and patterns of the gilt-bronze shoes were closely examined. Then, a design drawing of gilt-bronze shoes was created through field measurement and they were recreated on the basis of the analysis. The original form of the restored products were manufactured through cutting out the outward form, bore carving, engraving, molding, plating, and an assembly process. In the restoration process, this study examined the formal characteristics of gilt-bronze shoes, manufacturing techniques, and archetypes during Baekje's late Hanseong era. Products restored from this study are expected to be used as achievements for more easily understanding the culture of Baekje.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.580-589
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• 2019

Indonesia has a very short supply of electricity. As a solution to this problem, plans for construction of thermal power plants are increasing. Thermal power plant require the cooling water system to cool the overheated engine and equipment that accompany power generation, and the circulation water pump chamber among the cooling water system are generally designed according to the ANSI (1998) standard. In this study, the design criterion $20^{\circ}$ for the spreading angle of the ANSI (1998) of the layout of the circulating water pump chamber can not be satisfied on the K-coal thermal power plant site condition in Indonesia. Therefore, 3-D numerical model experiment was carried out to obtain a hydraulically stable flow and stable structure. The Flow-3D model was used as numerical model. In order to examine the applicability of the Flow-3D model, the flow study results around the rectangular structure of Rodi (1997) and the numerical analysis results were compared around the rectangular structures. The longitudinal velocity distribution derived from numerical analysis show good agreement. In order to satisfy the design velocity in the circulating water pump chamber, a rectangular baffle favoring velocity reduction was applied. When the approach velocity into the circulating water pump chamber was occurred 1.5 m/s ~ 2.5 m/s, the angle of the separation flow on the baffle was occurred about $15^{\circ}{\sim}20^{\circ}$. By placing the baffle below the separation flow angle downstream, the design velocity of less than 0.5 m/s was satisfied at inlet bay.

• Journal of Conservation Science
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• v.35 no.3
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• pp.217-225
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• 2019

The chimi(ridge-end tile) of Wangheungsa temple is the oldest in our country. The upper part of the chimi was excavated from the southern side of Wangheungsa temple and the lower part from the northern side. These parts are considered to be portions of the same chimi, because they are similar in shape and are excavated from two sides of the same temple structure. However, the original shape of the chimi cannot be determined owing to substantial deterioration. Hence, in this study, replicas of the deteriorated chimi portions of Wangheungsa temple were fabricated by employing 3D scanning technology and the computer numerical control machining method. While observing the bending phenomenon of the chimi, the proposed model was warped realistically on the basis of the bending direction of the actual chimi. Consequently, the restoration process was modified several times. The results indicated that no gaps can be found between the upper and lower parts, and the corresponding patterns connect naturally. Furthermore, the proposed method is contactless, safe, operable, reproducible, and appropriate for restoration of artifacts. Additionally, the modeling data is semi-permanent. Hence, if modelling data is appropriately applied as per the characteristics of artifacts, it can be utilized in various fields such as virtual exhibitions, hands-on exhibitions, cultural heritage restoration, and production of teaching aids and souvenirs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.20-26
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• 2019

Where hydraulic structures are to be installed over the entire width of a river or stream, usually a bed protection structure is to be installed. However, a local scour occurs in which the river bed downstream of the river protection system is eroded due to the influence of the upstream flow characteristics. This local scour is dominant in the flow and turbulence characteristics at the boundary of the flow direction and in the material of the bed materials, and may gradually become dangerous over time. Therefore, in this study, we compared the turbulence patterns in the local scour hole at the downstream of the river bed protection with the results of the analysis of the mobile bed experiment, and compared with the application of OpenFoam, a three dimensional numerical analysis model. The distribution of depth-averaged relative turbulence intensities along the flow direction was analyzed. In addition to this result, the stabilization of scour hole was compared with the bed shear stress and Shields parameter, and the results were compared by changing the initial turbulent flow conditions. From the results, it was confirmed that the maximum depth of generation of the three-stage was dominantly developed by the magnitude of depth-averaged relative turbulence intensity rather than the mean flow velocity. This result also suggests that design, construction or gate control are needed to control the depth-averaged relative turbulence intensities in order to reduce or prevent the local scour faults that may occur in the downstream part of the bed protection.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.52-52
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• 2019

산채는 사람에 의하여 개량 육성되어 논밭에서 재배하고 있는 농작물과 달리 자연 그대로 산야에서 자생하는 식물 중 식용으로 가능한 것을 말한다. 우리나라 산야에는 480종의 식물이 식용으로 이용될 수 있다고 하나 현재 전국에서 재배하고 있는 작목은 36종으로 추정되며, 앞으로도 80여 종이 개배 가능한 작물로 추정된다. 산채류의 이용형태별 생산가능시기는 3~5월의 생채 생산과 6~7월의 건채 생산으로 소비자의 기호에 부합하는 신선 생채의 소비한계는 제한되어 있기 때문에 재배유형별 생채 수량검정을 통해 수확시기 연장 및 재배품목을 다양화 시킬 필요 있다. 이에 본 시험은 산채류 재배유형별 수확기간을 구명하고자 표고 500 m의 전북 남원시 허브산채시험장에서 2018년 5월 말 갯기름나물 등 15 종을 노지와 하우스에 정식하여 각 작물의 생육특성, 수확한계기 등을 조사하였다. 1년차 지상부 생육특성을 조사한 결과 참취, 개미취, 섬쑥부쟁이, 질경이, 갯기름나물, 두메부추, 돌단풍, 참당귀의 경우 초장, 엽장 등은 노지보다 하우스에서 높은 편이었고 생존율은 비슷하거나 하우스에서 더 높은 경향을 보였다. 우산나물, 단풍취의 생존율은 하우스에서 더 높았으나 생육 초기 엽소현상으로 인해 1년차 생육은 노지, 하우스에서 둘 다 저조하였고 곤달비, 어수리, 곰취, 눈개승마의 경우 노지에서는 7월 중순이후 지상부가 전부 고사하였으나 하우스에서는 생존율이 상대적으로 양호하여 11월 상순까지 후기 생육을 하였다. 2년차 산채류 출현기 조사한 결과 하우스 재배에서 산마늘이 2월 중순으로 가장 빨랐고 갯기름나물, 곤달비 등 10종이 2월 하순에 출현하였으며 참당귀 3월 상순, 단풍취 및 우산나물 3월 중순, 돌단풍이 가장 늦은 3월 하순에 출연하였다. 생체수확 시기는 갯기름나물, 눈개승마, 산마늘, 두메부추, 섬쑥부쟁이는 3월 중순부터 가능했고 곤달비 등 12개종은 3월 하순, 우산나물은 4월 상순, 돌단풍은 4월 중순으로 가장 늦게 생체수확이 가능했다. 노지 재배의 경우 산마늘과 눈개승마가 3월 중순으로 가장 빨랐고 갯기름나물 등 10종이 3월 하순에 출현하였으며 돌단풍, 참당귀, 단풍취가 4월 상순으로 가장 늦은 출연을 보였다. 생체수확 시기는 눈개승마와 산마늘이 4월 상순으로 가장 빨랐으며 갯기름나물 등 10종이 4월 중순부터 가능했고 돌단풍, 참당귀, 단풍취가 4월 하순으로 가장 늦었다. 수확한계기 조사 결과 눈개승마, 산마늘, 우산나물은 하우스 및 노지재배에서 20일정도로 가장 짧았으며 그 외 작물들은 계속적으로 수확이 가능하였으나 6월 상순 이후에는 품질이 나빠져 생체상품으로서 가치가 없었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.558-564
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• 2021

The water purifier market has increased rapidly in recent years. The welding technology of the evaporator is a key component that determines the level of ice production and the cold water performance of an ice purifier. The finger type evaporator of an ice purifier can remove ice and is divided largely into an instant heat method and a hot gas method. In the hot gas type evaporator, particularly during the production process, the pinhole phenomenon inside the copper pipe and clogging problems occur intermittently when welding high-pressure pipes due to the high-temperature oxygen welding. Its use in a water purifier can cause a problem in that ice and cold water do not form, and repairs cannot be made on site. To solve this problem, in this study, a cap jig was applied to improve the welding defect of the hot gas evaporator. In addition, the oxygen welding flame size was adjusted so that the heat source could be well supplied to the cap jig, and the effectiveness was confirmed through a wave pressure test, a test, and a thermal shock test.

• Journal of Wetlands Research
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• v.23 no.2
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• pp.154-162
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• 2021

The naturally opened Han river estuary is a place where the flows of the Han river, Imjin river, Yaesung river meet with West Sea of Korea, so the hydrodynamic mechanism(Impact-Response) structure of Han river estuary is complex. Continuous observation and measurement due to the morphological characteristics at the estuary are required to maintain the estuary environment and river management facilities. However, the Sannam wetland(the study area) is in the military operation area. Therefore, Sannam wetland has the limited access under the control from military office. In 2020, there had a natural disaster due to flooding in August and COVID-19, and it made a survey hard. The noncontact survey technique, the analysis of LANDSAT images at Sannam wetland, was applied to analyze riverbed fluctuation and morphological transformation around Sannam wetland. LANDSAT images obtained from EarthExplorer, USGS and analyzed by QGIS. The analysis was performed based on the area and the distance near Sannam wetland. As a result, an erosion was happened on the downstream of the study area, and the upstream of the study area did not have any serious sediment transport. Considering the resolution of LANDSAT images, this noncontect survey technique is applicable to manage the study area. From the analysis of LANDSAT images, it is assumed that the tidal effect is greater than the inflow from the upstream. The pattern change of tidal response causes the damage of the river facilities near the Hangang river estuary.