• 대한지리학회지
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• 제47권3호
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• pp.347-358
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• 2012

이 연구에서는 겨울과 여름철의 풍속변화를 파악하기 위하여 남한 13개 지점의 1961년부터 2010년까지 1월과 8월의 평균풍속과 최대풍속, 강풍일수, 폭풍일수를 분석하였다. 평균풍속과 최대풍속은 1월과 8월에 해안에 위치한 부산, 제주, 울산, 포항에서 비교적 큰 폭으로 감속하였다. 강풍일수와 폭풍일수도 해안에 위치한 지점에서 감소한 경향이다. 1월 풍속이 크게 감소한 지점에서 풍속과 평균기온 사이에 비교적 높은 음의 상관관계가 있는 반면, 8월에는 두 변수 간의 상관관계가 낮다. 또한 강풍일(평균풍속 5m/sec 이상일)과 폭풍일(일 최대풍속 13.9m/sec 이상일)의 빈도가 비교적 높은 지점에서는 1월평균기온과 1월의 강풍일 및 폭풍일수 사이에 비교적 높은 음의 상관관계가 있다. 이는 1월의 바람 특성이 기온상승에 따라 바뀔 수 있다는 것을 시사한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권7호
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• pp.2977-2997
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• 2018

In big data era, fresh data grows rapidly every day. More than 30,000 gigabytes of data are created every second and the rate is accelerating. Many organizations rely heavily on real time streaming, while big data stream computing helps them spot opportunities and risks from real time big data. Storm, one of the most common online stream computing platforms, has been used for big data stream computing, with response time ranging from milliseconds to sub-seconds. The performance of Storm plays a crucial role in different application scenarios, however, few studies were conducted to evaluate the performance of Storm. In this paper, we investigate the performance of Storm under different application scenarios. Our experimental results show that throughput and latency of Storm are greatly affected by the number of instances of each vertex in task topology, and the number of available resources in data center. The fault-tolerant mechanism of Storm works well in most big data stream computing environments. As a result, it is suggested that a dynamic topology, an elastic scheduling framework, and a memory based fault-tolerant mechanism are necessary for providing high throughput and low latency services on Storm platform.

• Journal of Astronomy and Space Sciences
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• 제34권4호
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• pp.245-250
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• 2017

As a part of collaborative efforts to understand ionospheric irregularities, the Korea ionospheric scintillation sites (KISS) network has been built based on global positioning system (GPS) receivers with sampling rates higher than 1 Hz. We produce the rate of TEC index (ROTI) to represent GPS TEC fluctuations related to ionospheric irregularities. In the KISS network, two ground-based GPS sites at Kiruna (marker: KIRN; geographic: $67.9^{\circ}$ N, $21.4^{\circ}$ E; geomagnetic: $65.2^{\circ}$ N) and Chuuk (marker: CHUK; geographic: $7.5^{\circ}$ N, $151.9^{\circ}$ E; geomagnetic: $0.4^{\circ}$ N) were selected to evaluate the ROTI value for ionospheric irregularities during the occurrence of the 2015 St. Patrick's Day storm. The KIRN ROTI values in the aurora region appear to be generally much higher than the CHUK ROTI values in the EIA region. The CHUK ROTI values increased to ~0.5 TECU/min around UT=13:00 (LT=23:00) on March 16 in the quiet geomagnetic condition. On March 17, 2015, CHUK ROTI values more than 1.0 TECU/min were measured between UT=9:00 and 12:00 (LT=19:00 and 22:00) during the first main phase of the St. Patrick's Day storm. This may be due to ionospheric irregularities by increased pre-reversal enhancement (PRE) after sunset during the geomagnetic storm. Post-midnight, the CHUK ROTI showed two peaks of ~0.5 TECU/min and ~0.3 TECU/min near UT=15:00 (LT=01:00) and UT=18:00 (LT=04:00) at the second main phase. The KIRN site showed significant peaks of ROTI around geomagnetic latitude=$63.3^{\circ}$ N and MLT=15:40 on the same day. These can be explained by enhanced ionospheric irregularities in the auroral oval at the maximum of AE index

• 한국해양공학회지
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• 제24권1호
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• pp.68-75
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• 2010

Recently, the intensity and frequency of typhoons have been on the increase due to unusual weather phenomena and climate change. In particular, on September 13, 2003, typhoon MAEMI (0314) caused heavy damage in the provinces of Busan and Gyongnam, but also provided an opportunity to perform a variety of studies on storm surge. According to investigation reports on the damage resulting from typhoon MAEMI, the areas where coastal inundation occurred were located in reclaimed land under coastal development. In this study, through an image data analysis of historic and present day typhoons affecting Masan, we found that the inundation damage areas corresponded to reclaimed lands. Therefore, using the area around Busan, including the southeastern coast of Korea where typhoons lead to an increased storm surge risk, we performed a storm surge/inundation simulation, and examined the inundation effect on reclaimed land due to the intensified typhoons predicted for the future by climate change scenarios.

• Journal of Astronomy and Space Sciences
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• 제36권3호
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• pp.133-147
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• 2019

Challenging Minisatellite Payload (CHAMP) satellite magnetic data are used to investigate the latitudinal variation of the storm-time meso-scale field-aligned currents by defining a new metric called the FAC range. Three major geomagnetic storm events are considered. Alongside SymH, the possible contributions from solar wind dynamic pressure and interplanetary magnetic field (IMF) $B_Z$ are also investigated. The results show that the new metric predicts the latitudinal variation of FACs better than previous studies. As expected, the equatorward expansion and poleward retreat are observed during the storm main phase and recovery phase respectively. The equatorward shift is prominent on the northern duskside, at ${\sim}58^{\circ}$ coinciding with the minimum SymH and dayside at ${\sim}59^{\circ}$ compared to dawnside and nightside respectively. The latitudinal shift of FAC range is better correlated to IMF $B_Z$ in northern hemisphere dusk-dawn magnetic local time (MLT) sectors than in southern hemisphere. The FAC range latitudinal shifts responds better to dynamic pressure in the duskside northern hemisphere and dawnside southern hemisphere than in southern hemisphere dusk sector and northern hemisphere dawn sector respectively. FAC range exhibits a good correlation with dynamic pressure in the dayside (nightside) southern (northern) hemispheres depicting possible electrodynamic similarity at day-night MLT sectors in the opposite hemispheres.

• 한국물환경학회지
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• 제31권5호
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• pp.523-532
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• 2015

Hydrocyclone is widely used in industry, for its simple design, high capacity, low maintenance and low operational cost. The objective of this study is to develop hydrocyclone coagulation and filtration system. The system is made of hydrocyclone ballasted coagulation with polyaluminium chloride silicate (PACS) and upflow filter to treat micro particles in urban storm runoff. Roadside sediment particles (< $200{\mu}m$) was mixed with tap water to make various turbid suspensions to simulate urban storm runoff. The filter cartridge was filled with polyethylene media system and ran 1hr per everyday and total operation time were 8.19hrs and backwashing everyday after end of operation. The operation condition of flowrate was $8.2{\sim}11.9m^3/day$ (mean $10.1m^3/day$) and surface overflow rate (SOR) based on filter surface area was $45.5{\sim}65.9m^3/m^2/day$ (mean $55.7m^3/m^2/day$). The range of PACS dosage concentration was 14.0~31.5 mg/L. As the results of operation, the range of removal efficiency of turbidity, SS were 81.0~95.8% (mean 89.5%) 81.8~99.0% (mean 91.4%), respectively. An increase of filtration basin retention time brought on increased of removal efficiency of turbidity and SS, and increase of SOR brought on decreased of removal efficiency. During the first flush in urban area, storm runoff have an high concentration of SS (200~600 mg/L) and the filtration bed becomes clogged and decreased of removal efficiency. Backwashing begins when the drainage pipe valve at the filtration tank bottom is completely open (backwashing stage 1). Backwashing stage 2 was using air bubbles and water jet washing the media for 5 mins and open the drainage valve. After backwashing stage 1, 2, 61.83~64.04%, 18.53~27.51% of SS loading was discharged from filtration tank, respectively. Discharged SS loading from effluent was 7.12~14.79% and the range of residual SS loading in fliter was 2.26~5.00%. The backwashing effects for turbidity, SS were 89.5%, 91.4%, respectively. The hydrocyclone coagulation and filtration with backwashing system, which came out to solve the problems of the costly exchange filter media, and low efficiency of removing micro particles of filter type nonpoint treatment devices, is considered as an alternative system.

• 대한지리학회지
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• 제33권3호
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• pp.395-409
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• 1998

미국남부지방의 5개 도시를 연구지역으로 도시의 영향에 의한 강수특성변화를 파악하고 종관기상유형에 따른 특성을 규명하기 위하여 2 인치(50.08 mm) 이상의 일강수량을 가지는 강수일을 선택하여 3가지 강수유형(기단성 강수, 전선성 강수, 열대저기업성 강수)으로 구분하여 분석하였다. Houston, Dallas, 그리고 San Antonio에서는 기단성 강수가 발생할 때, 도시직역과 풍하측에 호우로 인한 강수량과 강수빈도의 증가가 나타나고 있으나 New Orleans와 Memphis에서는 종관적 분석을 통해서 볼 때 현저한 증가현상을 보이지 않는다. 경향면 분석겨로가는 전선성 강수와 열대저기업성강수 발생시 기단성 강수로 인한 호우보다 강한 경향성을 가지는 것을 보여주고, 호우로 인한 통강수량은 강수일수빈도보다 강한 경향성을 가진다. 잔차도 분석결과는 기단성 호우 발생시 도시지역과 풍하지역에 양의 잔차가 나타나는 것을 보여준다. 미국 남부의 5개도시에서 강수특성변화에 미치는 도시화의 영향에 대한 연구는 도시기후는 종관적으로 유사한 조건하일지라도 도시의 규모, 공간구조, 수체의 유무, 산업구조 등 다양한 특성에 따라 상이하게 반응함을 알 수 있었다.

• Journal of Astronomy and Space Sciences
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• 제39권4호
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• pp.145-158
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• 2022

The dynamics of the outer zone radiation belt has received a lot of attention mainly due to the correlation between the occurrence of enhancing relativistic electron flux and spacecraft operation anomalies or even failures (e.g., Baker et al. 1994). Relativistic electron events are often observed during great storms associated with ultra low frequency (ULF) waves. For example, a large buildup of relativistic electrons was observed during the great storm of March 24, 1991 (e.g., Li et al. 1993; Hudson et al. 1995; Mann et al. 2013). However, the dominant processes which accelerate magnetospheric radiation belt electrons to MeV energies are not well understood. In this paper, we present observations of Pc5 ULF waves in the recovery phase of the Bastille day storm of July 16, 2000 and electron and proton flux simultaneously oscillating with the same frequencies as the waves. The mechanism for the observed electron and proton flux modulations is examined using ground-based and satellite observations. During this storm time, multiple packets of discrete frequency Pc5 ULF waves appeared associated with energetic particle flux oscillations. We model the drift paths of electrons and protons to determine if the particles drift through the ULF wave to understand why some particle fluxes are modulated by the ULF waves and others are not. We also analyze the flux oscillations of electrons and protons as a function of energy to determine if the particle modulations are caused by a ULF wave drift resonance or advection of a particle density gradient. We suggest that the energetic electron and proton modulations by Pc5 ULF waves provide further evidence in support of the important role that ULF waves play in outer radiation belt dyanamics during storm times.

• 한국동물위생학회지
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• 제46권2호
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• pp.167-173
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• 2023

An 8-year-old female neutered Maltese dog exhibited signs of serious thunderstorm phobia including panting, wandering, shivering, hiding, crying or whining, or trying to escape from the house. In this study, we administered clomipramine and alprazolam and observed behavioral improvement for 3 years. Clinical symptoms measured according to the storm phobia assessment (SPA) were significantly high with an initial total score of 19 points. However, it improved to a total score of 8 on day 176 after drugs administration and returned to the normal level with the total score of 5 points on the 983 days. When the symptoms for the first 4 treatments and the last 4 treatments were compared in 2 groups, the total score of all clinical symptoms decreased to -62.83% in the last 4 treatments. This study found that treatment with alprazolam and clomipramine was associated with a decrease in clinical signs of storm anxiety, suggesting that two drugs would be effective in reducing symptoms caused by anxiety, thunderstorm phobia, and noise phobia. In this follow up study, we hope that more studies would be conducted on behavior modification for treatment of storm phobia in veterinary medicine.

• 한국수자원학회논문집
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• 제40권7호
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• pp.533-543
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• 2007

본 연구에서는 조선왕조실록의 문헌 기록 호우사상의 특성을 파악하고 정성적으로 평가하였다. 먼저, 조선왕조실록의 문헌기록에 대한 사상은 '큰비', '큰물', '홍수', '폭우'의 네 가지 키워드를 이용하여 추출하였다. '큰비'가 포함된 사상의 경우, 피해상황이나 규모 등이 자세하게 기록되지 않은 경우가 많았지만 '큰물', '홍수', '폭우'의 경우, 그 피해 정도나 규모가 상세하게 기록되어 있었다. 즉, '큰비'의 경우는 비의 절대량만으로 판단하여 기록된 것이고 '큰물', '홍수', '폭우'의 경우는 비의 절대량보다는 유출에 의해 피해가 비교적 컸던 경우 기록된 것으로 판단된다. 간단한 유효 우량 산정방법인 SCS방법을 적용하여 유효우량을 살펴본 결과에서는 대체로 '큰비'의 경우는 선행 5일 강수량의 크기가 작아 AMC-I 조건인 경우가 많았고 반대로 '큰물', '홍수', '폭우'의 경우는 선행 5일 강수량이 상당히 커 AMC-III 조건이 대부분 이었다. 이에 따라 강수량 대비 유효우량은 '큰물', '홍수', '폭우'의 경우가 '큰비'에 비해 훨씬 크게 나타났음을 확인할 수 있었다. 따라서 피해기록이 자세하게 기록되어 있는 경우는 유출로 인한 피해가 큰 경우라 할 수 있으며 '큰물', '홍수', '폭우' 문구가 포함된 기록들이 이에 해당한다고 할 수 있다.