• Title/Summary/Keyword: STORM

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Development of Convective Cell Identification and Tracking Algorithm using 3-Dimensional Radar Reflectivity Fields (3차원 레이더 반사도를 이용한 대류세포 판별과 추적 알고리즘의 개발)

  • Jung, Sung-Hwa;Lee, GyuWon;Kim, Hyung-Woo;Kuk, BongJae
    • Atmosphere
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    • v.21 no.3
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    • pp.243-256
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    • 2011
  • This paper presents the development of new algorithm for identifying and tracking the convective cells in three dimensional reflectivity fields in Cartesian coordinates. First, the radar volume data in spherical coordinate system has been converted into Cartesian coordinate system by the bilinear interpolation. The three-dimensional convective cell has then been identified as a group of spatially consecutive grid points using reflectivity and volume thresholds. The tracking algorithm utilizes a fuzzy logic with four membership functions and their weights. The four fuzzy parameters of speed, area change ratio, reflectivity change ratio, and axis transformation ratio have been newly defined. In order to make their membership functions, the normalized frequency distributions are calculated using the pairs of manually matched cells in the consecutive radar reflectivity fields. The algorithms have been verified for two convective events in summer season. Results show that the algorithms have properly identified storm cells and tracked the same cells successively. The developed algorithms may provide useful short-term forecasting or nowcasting capability of convective storm cells and provide the statistical characteristics of severe weather.

Wave Responses of Buoyant Flap-typed Storm Surge Barriers - Numerical Simulation (부유 플랩형 고조방파제의 파랑응답 - 수치모의)

  • Jeong, Shin-Taek;Ko, Dong-Hui;Park, Woo-Sun
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.21 no.2
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    • pp.196-208
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    • 2009
  • In this paper, wave responses of buoyant flap-typed storm surge barriers was studied numerically. Wave motions were modeled by using a linear potential wave theory, and behaviors of structures were represented as a Newton's 2nd law of motion. The near field region of the fluid was discretized as conventional quadratic iso-parametric elements, while the far field was modeled as infinite elements. Comparisons with the results from hydraulic model tests show that the present model gives good results. By using the model, the applicability of a buoyant flap-typed storm surge barrier in Masan bay was investigated considering field environmental conditions.

Risk analysis of road cave-in of storm sewer lateral using zoom camera (줌카메라를 활용한 빗물받이 연결관의 도로함몰 리스크 분석)

  • Han, Sangjong;Hwang, Hwankook
    • Journal of Korean Society of Water and Wastewater
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    • v.28 no.6
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    • pp.681-690
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    • 2014
  • It is known that sewer problems are the major causes of road cave-in. The objective of this study is to analyze the risk of road cave-in due to storm sewer laterals. We investigated 174 storm sewer laterals using a zoom camera at O-dong area in Seoul. The causes of road cave-in were classified into five cases: breakage of rigid pipe, deformation of flexible pipe, out of pipeline alignment, changing pipe material or changing pipe diameter, and a poor linkage between lateral and sewer. In addition, all defects were sorted into five grades based on the severity rating at storm sewer laterals. In this study, the most fragile pipe materials were found to be concrete pipe and polyethylene pipe, which recorded 2.3 and 1.69 defect rates. With regard to the causes of road cave-in, deformation of flexible pipe has a large influence on road cave-in at present. On a long-term basis, the two causes, out of pipeline alignment and a poor linkage between lateral and sewer, could have more influence on road cave-in.

Design of InfiniBand RDMA-based Network Structure of Apache Storm (InfiniBand RDMA 기반 Apache Storm의 네트워크 구조 설계)

  • Yang, Seokwoo;Son, Siwoon;Choi, Seong-Yun;Choi, Mi-Jung;Moon, Yang-Sae
    • Proceedings of the Korea Information Processing Society Conference
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    • 2017.11a
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    • pp.679-681
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    • 2017
  • Apache Storm은 대용량 데이터 스트림을 처리하기 위한 실시간 분산 병렬 처리 프레임워크이며, 이를 사용해 다수의 프로세스 및 스레드를 동시에 동작시킬 수 있다. 하지만, 이러한 멀티 프로세스 및 스레드 환경을 제공하는 Storm은 많은 네트워크 시스템 호출을 수행하고, 이는 잦은 문맥 전환(context switch), 운영체제로의 버퍼 복사, 운영체제 내의 버퍼 복사 등으로 인해 CPU 과부하 문제를 발생시킬 수 있다. 이러한 문제는 고성능 네트워크 장비인 InfiniBand의 IPoIB(IP over InfiniBand) 통신을 사용할 때, InfiniBand가 지원하는 대역폭(bandwidth) 대비 저용량 데이터의 송수신으로 인해 더 잦은 문맥 전환과 버퍼 복사가 발생하여 CPU 과부하 문제가 더욱 심각해진다. 따라서, 본 논문에서는 InfiniBand의 RDMA(Remote Direct Memory Access)를 Storm에 적용하는 설계안을 제시함으로써 CPU 과부하 문제를 해결한다.

Grid-Based KlneMatic Wave STOrm Funoff Yoncheon Dam watershed. (격자기반의 운동파 강우유출모형 개발(II) - 적용 예(연천댐 유역을 대상으로) -)

  • Kim, Seong-Jun;Chae, Hyo-Seok;Sin, Sa-Cheol
    • Journal of Korea Water Resources Association
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    • v.31 no.3
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    • pp.309-315
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    • 1998
  • The grid-based KIneMatic wave STOrm Runoff Model (KIMSTORM) was applied to YoncheonDam watershed (1,875km2) located in the Imjin river basin of the Korea. Six maps which are DEM(Digital Elevation Model), stream, flow path, soil, land use and Thiessen network, were used for input data. The simulated streamflows resulting from two selected storm events agreed well with the observed flows at the watershed outlet. The results of temporal variations and spatial distributions are presented by using GRASS. Keyword : grid-based, storm-runoff model, GRASS-GIS, Yoncheon dam watershed.

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Runoff Analysis due to the Moving Storm (이동강우에 의한 유출영향분석)

  • Han, Kun-Yeun;Jeon, Min-Woo;Choi, Kyu-Hyun
    • Journal of Korea Water Resources Association
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    • v.37 no.10
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    • pp.823-836
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    • 2004
  • Using the simple geometry for the idealized catchment consisting of two plane surfaces and a stream between them, runoff was analysed for the moving storms based on the kinematic wave equation. The storm velocity applied in this study was 0.25∼2.0 m/s moving up, down and cross direction of catchment. Applied rainfall distribution types are uniform, advanced, delayed, intermediate type. The results indicate that the moving storms of cross direction generate the largest peak runoff, and the smallest runoff appears in the case of up stream direction. The sensitivity of runoff to rainfall distribution types decreases as storm velocity increases. It is clear that faster storm velocity generates faster peak time and becomes thin hydrographs rapidly.

Simulation of Moving Storm in a Watershed Using Distributed Models

  • Choi, Gye-Woon;Lee, Hee-Seung;Ahn, Sang-Jin
    • Korean Journal of Hydrosciences
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    • v.5
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    • pp.1-16
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    • 1994
  • In this paper distributed models for simulating spatially and temporally varied moving storm in a watershed were developed. The complete simulation in a watershed is achieved through two sequential flow simulations which are overland flow simulation and channel network flow simulation. Two dimensional continuity equation and momentum equation of kinematic approximation were used in the overland flow simulation. On the other hand, in the channel network simulation two types of governing equations which are one dimensional continuity and momentum equations between two adjacent sections in a channel, and continuity and energy equations at a channel junction were applied. The finite difference formulations were used in the channel network model. Macks Creek Experimental Watershed in Idaho, USA was selected as a target watershed and the moving storm on August 23, 1965, which continued from 3:30 P.M. to 5:30 P.M., was utilized. The rainfall intensity fo the moving storm in the watershed was temporally varied and the storm was continuously moved from one place to the other place in a watershed. Furthermore, runoff parameters, which are soil types, vegetation coverages, overland plane slopes, channel bed slopes and so on, are spatially varied. The good agreement between the hydrograph simulated using distributed models and the hydrograph observed by ARS are Shown. Also, the conservations of mass between upstreams and downstreams at channel junctions are well indicated and the wpatial and temporal vaiability in a watershed is well simulated using suggested distributed models.

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Storm-Time Behaviour of Meso-Scale Field-Aligned Currents: Case Study with Three Geomagnetic Storm Events

  • Awuor, Adero Ochieng;Baki, Paul;Olwendo, Joseph;Kotze, Pieter
    • Journal of Astronomy and Space Sciences
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    • v.36 no.3
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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.

Proposal for application of spatial data and quality check criteria for estimating damage from storm and flood (풍수해 피해 추정을 위한 공간정보 DB의 활용방안 및 품질 점검 기준 제안)

  • Won, Seok-Hwan;Kim, Hyeon-Deok;Kim, Sang-Min
    • Journal of Cadastre & Land InformatiX
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    • v.50 no.2
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    • pp.81-100
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    • 2020
  • The purpose of this study was to propose applicability of spatial data and quality check criteria for estimating damage from storm and flood. Using the data from the National Disaster Management System and National Spatial Data Infrastructure, spatial database for estimation of storm and flood damage has been mapped to each type of damage. This was proposed as the quality check criteria for damage analysis. Through this study, it is possible to utilize the spatial database for estimating storm and flood damage. The reliability of analysis results are ensured through the quality check criteria.