• Journal of Korean Society of Disaster and Security
• /
• v.13 no.3
• /
• pp.15-28
• /
• 2020

Hydrological data is very important in understanding the hydrological process and identifying its characteristics to protect human life and property from natural disasters. In particular, hydrological analysis are often performed assuming that hydrological data are stationary. However, recently climate change has raised the issue of climate stationary, and it is necessary to analyze the nonstationary of the climate. In this study, a method to analyze the stationarity of hydrological data was examined using the annual precipitation of 37 meteorological stations with long - term record data. Therefore, in this study, the stationary was determined by analyzing the persistence, trend, and stability using annual precipitation. Overall results showed that a trend was observed in 4 out of 37 stations, stable was investigated at 15 stations, and persistence was shown at 4 stations. In the stationary analysis using the annual precipitation data, 25 stations (67% of 37 stations) were nonstationary.

• Proceedings of the Safety Management and Science Conference
• /
• 2005.05a
• /
• pp.379-392
• /
• 2005

The size of state in Korea is like Israel, this country's venture capital is ruled by government. This venture capital's character is below: the concentration on research of venturer affect positively at quality of products. This paper lies with venture capital's risk character & performance. The results show that Korean venture capitals have lager unsystematic risk than systematic risk, which implies they specialize in specific business and/or regional areas instead of diversification. The Sharpe & Jensen measures reveal that the performances of Korean venture capitals are very low relative to even the market portfolio(Kospi) and Kosdaq Venture Index. Contrary to this, Venture firm's performance according to Entrepreneurship will cause to push up stock price.

• Journal of Korea Water Resources Association
• /
• v.47 no.5
• /
• pp.411-420
• /
• 2014

The water resources sustainability is becoming an important issue in consideration of hydrologic uncertainty by global warming and climate change. This study is to assess the water supply performance for the major multipurpose dams using sustainability index. Parameters, mostly utilized in water resources system assessment, are selected in respect of applicability and flexibility, and those parameters are used as a variable of the composite index. In practice, the composite index including reliability, resiliency, vulnerability and maximum deficit are applied to 15 multipurpose dams and 4 major basins. And to conclude, Daechungdam in the Geum river basin and Imhadam, Hapchondam and Namgangdam in the Nakdong river basin show low sustainability comparing with other dams. The Nakdong river basin needs to develop alternatives to improve water supply stability because it indicates the most poor sustainability level.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.6
• /
• pp.1070-1077
• /
• 2022

The International Maritime Organization has recently strengthened its marine environment regulations. The energy efficiency index has long been an important indicator of ship design, and now, energy efficiency is being enforced for existing ships as well as new ships. To increase the energy efficiency of existing ships, methods such as retrofitting the bow bulb, selecting an optimized trim during ship operation, and installing an energy saving device have been applied. In this study, the ship resistance was numerically simulated using computational fluid dynamics (CFD) under various bow and stern trim conditions. In addition, the bulb was redesigned to further improve the resistance performance under the selected trim conditions. When the improved bulb was applied, the effective horse power increased by approximately 5%. It is, however, necessary to verify whether the redesigned bulb can reduce ship resistance in waves.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.5-5
• /
• 2023

제3차 우주개발 진흥 기본계획의 일환으로써 개발되는 차세대 중형위성 5호인 수자원위성은 수자원/수재해 감시 전용 위성으로 2025년 발사 예정이다. 수자원위성의 메인 센서인 C-band 영상레이더(Synthetic Aperture Radar, SAR)는 기상조건 및 주야 상관없이 지표면 관측이 가능한 센서로 급변하는 수재해 양상에 효과적으로 대응하기 위해 탑재된 센서이다. 본 연구사업은 차세대 수자원위성의 효과적 활용 방안 및 SAR 자료기반의 활용산출물 및 주제도 서비스를 위한 알고리즘 구조설계 및 표출시스템 시범개발을 목표로 하고 있으며, 홍수/가뭄/안전/환경모니터링을 주제로 수자원 및 원격탐사 분야의 다학제적 전문가들로 구성된 컨소시엄을 구성하여 추진하고 있다. 본 연구의 내용은 가뭄 모니터링을 위해 개발 중인 SAR 기반 토양수분과 농업적 가뭄지수 산정 알고리즘 개발 및 공간적 표출을 포함한다. 토양수분은 SAR 영상에서 지표피복별로 추출된 후방산란계수와 수문학적 개념의 융합을 통해 논/밭/산림에 대해 산정한다. 물리적 특성에 기반한 변화탐지모델을 활용해 토양수분량을 추출 후, 기계학습기법과 S C S - C N 방법에서 파생된 수문학적 개념 5일 선행강우량과 결합한 토양수분 산정 알고리즘을 개발하였다. 산정된 토양수분을 기반으로, 논 지역은 벼 재배에 따른 담수 시기를 고려한 토양의 포화/불포화상태, 밭 지역은 토양 종류에 따른 토양의 물리적 특성, 산림 지역은 수문학적 개념 및 식생지수를 활용하여 가뭄 판단 기준을 구축하고, 가뭄의 해갈 여부와 해갈되는 시점의 강우량을 산정 가능한 알고리즘을 개발하였다. 개발된 가뭄 모니터링 기법은 향후 고도화, 최적화 및 안정화를 통해 수자원위성의 핵심 활용기술로써 구현할 계획이다.

• Progress in Medical Physics
• /
• v.26 no.2
• /
• pp.112-117
• /
• 2015

In order to establish the quality control on patient safety following the guideline presented by American Association of Physicists in Medicine (AAPM) TG-100 committee, we aim to analyze the modes based on errors occurred during treatment of patients at the radiation oncology department at Yeungnam University Hospital and establish a quality control guideline for patient safety when patient-centered radiation treatment is conducted. We aim to analyze the errors that can occur during radiation treatment at the radiation department, and assess the frequency of error, the severity of error affecting patients, and probability of proceeding without noticing error, with scores. The places where errors can take place were divided into CT simulation treatment room, treatment planning room, and treatment room for the analysis. In CT simulation treatment room, an error from using the immobilization device showed the highest Risk Priority Number (RPN) value of 60, and an error from simulation treatment information input showed the lowest of 6. In treatment planning room, an error from selecting the radiation dose calculation model showed the highest RPN value of 168, and an error of patient treatment start date showed the lowest of 36. In treatment room, a Table Bar error showed the highest RPN value of 252, a weight change error showed 190, and a Pillow error showed the lowest of 24.

• Applied Chemistry for Engineering
• /
• v.31 no.3
• /
• pp.277-283
• /
• 2020

The smoke hazard assessment of building materials focusing on smoke performance index-II (SPI-II) and smoke growth index-II (SGI-II) was investigated. The test species used were Japanese cedar, spruce, lauan, and red pine. The smoke characteristics of wood specimen were investigated using a cone calorimeter (ISO 5660-1). SPI-II was measured after the combustion reaction increased by 1.31~2.15 times based on red pine. The fire risk by SPI-II increased in the order of spruce, lauan, Japanese ceda, and red pine. SGI-II increased by 1.18~2.55 times compared to that of Japnese ceda. The fire risk caused by SGI-II increased in the order of Japanese ceda, spruce, lauan, and red pine. CO_mean concentrations were ranged from 58 to 133 ppm, which was higher than permissible exposure limits of the occupational safety and health administration (OSHA), 50 ppm. Therefore, woods such as red pine containing various volatile organic substances, were considered to be highly smoke hazardous due to low SPI-II and high SGI-II.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.4
• /
• pp.1792-1798
• /
• 2013

The purpose of this study was to investigate effect of type of physical therapy (spinal stabilization exercise and manual therapy) on pain index and disability index in acute and subacute patients with low back pain (LBP). 23 patients with LBP participated and were randomly assigned. Manual therapy and spinal stabilization exercise was applied for 15-minute sessions occurred 3 sessions a week, for 4 weeks. All subjects received conservative therapy for 30-minute. Visual analogue scale (VAS) and Korean version of Oswestry disability index (ODI-K) were measured before and after treatment. There was significant difference in VAS and ODI-K between before and after both treatment (p<.05). There was significant difference in change rate of VAS between manual therapy and spinal sabilization exercise (p<.05), but not in change rate of ODI-K (p>.05). Thus, it is suggested that spinal stabilization exercise is helpful to reduce pain safely in acute and subacute patients with LBP.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.27 no.2
• /
• pp.19-33
• /
• 2024

CCTV for crime prevention is expanding; however, due to the absence of guidelines for determining installation locations, CCTV is being installed in locations unrelated to areas with frequent crime occurrences. In this study, we developed a CCTV Priority Installation Index and applied it in a case study area. The index consists of crime vulnerability and surveillance vulnerability indexes, calculated using machine learning algorithms to predict crime incident counts per grid and the proportion of unmonitored area per grid. We tested the index in a pilot area and found that utilizing the Viewshed function in CCTV visibility analysis resolved the problem of overestimating surveillance area. Furthermore, applying the index to determine CCTV installation locations effectively improved surveillance coverage. Therefore, the CCTV Priority Installation Index can be utilized as an effective decision-making tool for establishing smart and safe cities.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.22 no.7
• /
• pp.791-799
• /
• 2016

The purpose of this work is to analyse the impact of new accident risks on maritime safety in Korea. The new accident risks have been induced from new/rare or unprecedented events in world maritime transportation, as identified by 46 experts in the previous study. To measure the impact of these new accident risks on maritime safety in Korea, the statistical accident data reported by the Korean Maritime Safety Tribunals (KMST) has been used for calculation, and the concept of Risk Index (RI) = Frequency Index (FI) + Severity Index (SI)established in a Formal Safety Assessment (FSA) by the IMO has also been introduced. After calculating two kinds of weight for FI and SI from the statistical accident data, high ranked scenarios were identified and their relationships between new risks and these scenarios were analysed. The results from this analysis showed, the root cause of the top-ranked scenario to be "developing high technology", which leads to "shorten cargo handling time". These results differed from optimum RCOs such as "business competition" and "crewing problems" which were identified in the previous study.