• 대기
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• 제18권4호
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• pp.355-365
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• 2008

Synoptic and climatological characteristics of heat waves over Korea and Europe as well as their biometeorological impacts were compared. In July of 1994, excess deaths of about 2,388 in the population of South Korea are estimated by the modified excess death calculation algorithm ofKysely (2004). The excess deaths correspond to the net mortality increase of 12.5% in July of 1994 if we compare the estimated value to the expected number of deaths in this month (i.e., about 19,171). The comparative study of heat waves in Korea and Europe shows that the record-breaking heat waves in both regions are closely associated with prolonged droughts. In particular, reduction of soil moisture, precipitation and cloud cover and enhancement of insolation during the drought periods are very likely to be related to the increase in the intensity and the duration ofheat waves. Climate models predict that the frequency, intensity, and duration of heat waves in the 21 st century will be greatly enhanced in both areas. In order to reduce the biometeorological and socioeconomic impacts due to heat waves, not only the development of heat-related mortality prediction model that can be widely applied to many climate regimes, but also studies on the climatological association between extreme temperatures and abnormal hydrological cycle are needed.

• Smart Structures and Systems
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• 제8권2호
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• pp.219-237
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• 2011

This paper presents novel research into the source localization of multiple impacts. Source localization technology for single impact loads in a plate structure has been used for health monitoring. Most of research on source localization has been focused only on the localization of single impacts. Overlapping of dispersive waves induced by multiple impacts and reflection of those waves from the edge of the plate make it difficult to localize the sources of multiple impacts using traditional source localization technology. The method solving the overlapping problem and the reflection problem is presented in the paper. The suggested method is based on pre-signal processing technology using band pass filter and optimal filter. Results from numerical simulation and from experimentation are presented, and these verify the capability of the proposed method.

• Journal of Astronomy and Space Sciences
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• 제32권1호
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• pp.1-11
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• 2015

Earth's magnetopause separating the fast and often turbulent magnetosheath and the relatively stagnant magnetosphere provides various forms of free energy that generate low-frequency surface waves. The source mechanism of this energy includes current-driven kinetic physical processes such as magnetic reconnection on the dayside magnetopause and flux transfer events drifting along the magnetopause, and velocity shear-driven (Kelvin-Helmholtz instability) or density/pressure gradient-driven (Rayleigh-Taylor instability) magnetohydro-dynamics (MHD) instabilities. The solar wind external perturbations (impulsive transient pressure pulses or quasi-periodic dynamic pressure variations) act as seed fluctuations for the magnetopause waves and trigger ULF pulsations inside the magnetosphere via global modes or mode conversion at the magnetopause. The magnetopause waves thus play an important role in the solar wind-magnetosphere coupling, which is the key to space weather. This paper presents recent findings regarding the generation of surface waves (e.g., Kelvin-Helmholtz waves) at the Earth's magnetopause and analytic and observational studies accountable for the linking of the magnetopause waves and inner magnetospheric ULF pulsations, and the impacts of magnetopause waves on the dynamics of the magnetopause and on the inner magnetosphere.

• Structural Engineering and Mechanics
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• 제85권4호
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• pp.501-510
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• 2023

Horizontally polarized shear waves (SH) have numerous applications in various scientific, engineering, and medical fields. The study deals with an investigation of SH-waves in a thin microstructural plate. The plate has been mathematically modelled by employing size dependent consistent couple stress theory, which involves a length parameter, known as characteristic length. Characteristic length is assumed to be of the order of internal microstructures of the material. Dispersion relations have been calculated for the propagation of SH-waves using different set of boundary conditions. Group velocity of the SH-waves has been calculated by using an analytical approach. The mathematical results obtained in the problem are discussed in detail and the impacts of characteristic length parameter and thickness of plate are presented on phase velocity of SH-waves through graphical illustrations.

• 환경정책연구
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• 제14권3호
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• pp.21-40
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• 2015

폭염은 과거 하절기에도 있어 왔던 현상이나, 최근 기후변화로 인하여 발생빈도 및 강도가 심화되고 폭염 발생시기의 불확실성이 가중됨에 따라 그 피해는 더욱 커지고 있다. 이에 폭염 대응은 폭염 발생 후 대응뿐만 아니라 사전에 그 피해를 예방할 수 있도록 중장기적 차원의 접근이 요구된다고 할 수 있다. 이에 국내 폭염 대응은 현재의 폭염에 대응하는 단기적인 대책에 미래 기후변화를 고려한 사전 예방적 차원의 관련 분야를 망라하는 포괄적 대책, 그리고 이를 중장기적으로 관리함으로써 수정 보완해가는 대책으로 수립되어야 한다. 국내 폭염으로 인한 피해 및 이에 대한 현재의 국내 폭염 대책을 고찰하고 대책통합과 적응관리의 프레임워크를 적용하여 기후변화를 고려한 폭염 대응의 중장기적 적응대책 수립 관리 방안을 제시하였다.

• 한국물환경학회지
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• 제40권2호
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• pp.89-100
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• 2024

Climate change has a broad impact on the entire water environment, and this impact is growing. Climate adaptation in water supply systems often involves quantity and quality control, but there has been a lack of research examining the impacts of climatic factors on water supply productivity and operation conditions. Therefore, the present study focused on, first, building a database of climatic factors and water purification operating conditions, and then identifying the correlations between factors to reveal their impacts. News big data was analyzed with keywords of climatic factors and water supply systems in either nationwide or region-wide analyses. Metropolitan area exhibited more issues with cold waves whereas there were more issues with drought in the Southern Chungcheong area. A survey was conducted to seek experts' opinions on the climatic impacts leading to these effects. Pre-chlorination due to drought, high-turbidity of intake water due to rainfall, an increase of toxins in intake water due to heat waves, and low water temperature due to cold waves were expected. Pearson correlation analysis was conducted based on meteorological data and the operating data of a water purification plant. Heavy rain resulted in 13 days of high turbidity, and the subsequent low turbidity conditions required 3 days of high coagulant dosage. This insight is expected to help inform the design of operation manuals for waterworks in response to climate change.

• 천문학회보
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• 제39권1호
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• pp.77.1-77.1
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• 2014

Gravitational waves predicted by the general relativity almost 100 years ago have been implicated indirectly only by astrophysical observations such as the orbital evolution of binary pulsars. The advanced detectors of gravitational waves will become operational in a few years and they are expected to make direct detection of gravitational wave signal coming from merging of binaries composed of neutron stars or stellar mass black holes from external galaxies. Korean Gravitational Wave Group (KGWG) is contributing to the possible detection through the data analysis of LIGO and Virgo. We summarize the perspectives of the gravitational wave research and the impacts of the detection in the near future in astronomy and astrophysics.

• 대기
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• 제17권4호
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• pp.463-470
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• 2007

This study aims to assess the impact of the hot summer weather on daily mortality in Busan. Daily total all-caused mortality in the entire population in Busan has been examined during 1991-2005. The daily deaths were standardized to account for the long-term trend in mortality and their seasonal and weekly cycles. We found the net increase (about 8.2%) of excess deaths during the extraordinary heat wave period in July of 1994. It corresponds to the excess deaths of 109.5 during the month. The abnormality of temperature extremes in July of 1994 and their impacts on human health were also investigated. Unusual heat wave appeared in the first ten days in July of 1994. The excess deaths are likely to be attributable to the record-breaking heat waves. The result suggests that unusual early heat waves would be dangerous, even for inhabitants who live in an acclimated region to the heat waves such as Busan.

• Smart Structures and Systems
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• 제24권4호
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• pp.525-539
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• 2019

In this study, vibration characteristics of a gravity-based caisson-foundation breakwater system are investigated for ambient and geometric parameters such as various waves, sea levels, and foundation conditions. To achieve the objective, following approaches are implemented. Firstly, operational modal analysis methods are selected to identify vibration modes from output-only dynamic responses. Secondly, a finite element model of an existing caisson-foundation breakwater system is established by using a structural analysis program, ANSYS. Thirdly, forced vibration analyses are performed on the caisson-foundation system for two types of external forces such as controlled impacts and wave-induced dynamic pressures. For the ideal impact, the wave force is converted to a triangular impulse function. For the wave flow, the wave pressure acting on the system is obtained from wave field analysis. Fourthly, vibration modes of the caisson-foundation system are identified from the forced vibration responses by combined use of the operational modal analysis methods. Finally, vibration characteristics of the caisson-foundation system are investigated under various waves, sea levels, and foundations. Relative effects of foundation conditions on vibration characteristics are distinguished from that induced by waves and sea levels.

• 대한지리학회지
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• 제45권5호
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• pp.573-591
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• 2010

이 연구에서는 지난 100년(1908~2007) 동안 서울에서 발생한 열파의 변화추세와 극심한 열파 발생 시 도심내 열환경과 사망자의 시공간적 패턴을 분석하고자 한다. 최근의 온난화 경향에도 불구하고 여름철 강수량증가에 의해 서울시의 열파 발생빈도 및 강도에는 뚜렷한 변화경향이 관찰되지 않는다. 전례 없이 강한 열파가 발생한 1994년 7월의 자동기상관측 및 Landsat TM 위성 영상 추출 열분포 자료들은 도심내 형성되는 고온의 열환경에 의해 노인 질병 사망자 수가 더욱 증가하였음을 잘 보여준다. 이 연구는 차후 도심 정비시 열환경 분포를 고려해야 하는 생리기후학적 근거를 제시하고 있다.