• Title/Summary/Keyword: Wind Field

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Planting Design Strategies and Green Space Planning to Mitigate Respirable Particulate Matters - Case Studies in Beijing, China - (미세먼지 저감을 위한 식재기법 및 도시 녹지계획 방향 - 중국 베이징시 사례를 중심으로 -)

  • Xu, Xi-ran;Kim, Jin-Oh
    • Journal of the Korean Institute of Landscape Architecture
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    • v.45 no.6
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    • pp.40-49
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    • 2017
  • The purpose of the research is to analyze the recent cases of green space planning and planting design in Beijing, one of the cities having the worst particulate matters (PM) pollution. This study comprehensively reviewed Chinese academic literature addressing green space planning to reduce PM pollution. In addition, we conducted field observations and interviews with public officials from Beijing Municipal Bureau of Landscape Design in charge of planning and management of green spaces in Beijing. After the extensive review of literature we derived tree planting principles to mitigate the impact of PM from urban road system, residential area, and industrial district. Using the principles we evaluated the three recent cases of planting design to mitigate PM: Beijing Fuxing Road, Fu Run Residential Area and Beijing Beiqi Multipurpose Vehicle Factory. We conclude that green space planning and trees planting are not effective in mitigating negative impact of PM pollution because of inadequate selection of trees and inconsiderate planting composition. We proposed to replace the tree species with the ones capable of reducing the spread of PM, and reorganize planting compositions that consider the directions and characteristics of urban wind flow. This study suggests desirable types of tree species and planting compositions for road, residential and industrial districts, and we expect that it provides helpful guidelines for making planting design and species selection to mitigate the impact of PM in urban landscape.

A Proposal of USN-based DER(Decentralized Energy Resources) Management System (USN 기반의 댁내 분산 전력 관리 시스템 제안)

  • Kim, Bo-Min;Kim, Jeong-Young;Bang, Hyun-Jin;Jang, Min-Seok
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2010.05a
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    • pp.871-874
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    • 2010
  • Needs for Smart Grid development are increasing all over the world as a solution to its problem according to depletion of energy resources, climatic and environmental rapidly change and growing demand for electrical power. Especially decentralized power is attracting world's attention. In this mood a new era for a unit scale of decentralized power environment is on its way in building. However there is a problem to have to be solved in the uniformity of power quality because the amount of power generated from renewable energy resources such as wind power and solar light is very sensitive to climate fluctuation. And thus this paper tries to suggest an energy management method on basis of real time monitoring for meteorological data. In the current situation of lacking in USN-based killer application in Smart Grid field, this paper proposes the USN-based DER management system which collects the meteorological data and control power system througout utilizing wireless sensor network technique this business. This communication technique is regarded to be efficient in aspects of installation cost and tits maintenance cost. The proposed EMS model embodies the method for predicting the power generation by monitoring and analyzing the climatic data and controling the efficient power distribution between the renewable energy and the existing power. The ultimate goal of this paper is to provide the technological basis for achieving zero-energy house.

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Spatio-Temporal Variations of Harmful Algal Blooms in the South Sea of Korea

  • Kim, Dae-Hyun;Denny, Widhiyanuriyawan;Min, Seung-Hwan;Lee, Dong-In;Yoon, Hong-Joo
    • Korean Journal of Remote Sensing
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    • v.25 no.6
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    • pp.475-486
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    • 2009
  • Harmful algal blooms (HAB) caused by the dominant species Cochlodinium polykrikoides (C. polykrikoides) appear in the South Sea of Korea and are particularly present in summer and fall seasons. Environmental factors such as water temperature, weather conditions (air temperature, cloud cover, sunshine, precipitation and wind) influence on the initiation and subsequent development of HAB. The purpose of this research was to study spatial and temporal variations of HAB in the Yeosu area using environmental (oceanic and meteorological) and satellite data. Chlorophyll-a concentrations were calculated using Sea-viewing Wide Field-of-view Sensor (SeaWiFS) images by an Ocean Chlorophyll 4 (OC4) algorithm, and HAB were estimated using the Red tide index Chlorophyll Algorithm (RCA). We also used the surface velocity of sequential satellite images applying the Maximum Cross Correlation method to detect chlorophyll-a movement. The results showed that the water temperature during HAB occurrences in August 2002-2008 was $19.4-30.2^{\circ}C$. In terms of the frequency of the mean of cell density of C. polykrikoides, the cell density of the HAB found at low (<300 cells/ml), medium (300-1000 cells/ml), and high (>1000 cells/ml) levels were 27.01%, 37.44%, and 35.55%, respectively. Meteorological data for 2002-2008 showed that the mean air temperature, precipitation, wind speed and direction, and sunshine duration were $22.39^{\circ}C$, 6.54 mm/day, 3.98 m/s (southwesterly), and 1-11.7 h, respectively. Our results suggest that HAB events in the Yeosu area can be triggered and extended by heavy precipitation and massive movement of HAB from the East China Sea. Satellite images data from July to October 2002-2006 showed that the OC4 algorithm generally estimated high chlorophyll-a concentration ($2-20\;mg/m^3$) throughout the coastal area, whereas the RCA estimated concentrations at $2-10\;mg/m^3$. The surface velocity of chlorophyll-a movement from sequential satellite images revealed the same patterns in the direction of the Tsushima Warm Current.

Experimental Study on Flow Direction of Fire Smoke in DC Electric Fields (DC 전기장 내에서 발생하는 화재연기 진행 방향에 대한 실험적 연구)

  • Park, Juwon;Kim, Youngmin;Seong, Seung Hun;Park, Sanghwan;Kim, Ji Hwan;Chung, Yongho;Yoon, Sung Hwan
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.27 no.5
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    • pp.675-682
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    • 2021
  • Fire accidents on land and at sea can cause serious casualties; specifically, owing to the nature of marine plants and ships, the mortality rate at sea from suffocation in confined spaces is significantly higher than that on land. To prevent such cases of asphyxiation, it is essential to install ventilation fans that can outwardly direct these toxic gases from fires; however, considering the scale of marine fires, the installation of large ventilation fans is not easy owing to the nature of marine structures. Therefore, in this study, we developed a new concept for fire safety technology to control toxic gases generated by fires from applied direct current (DC) electric fields. In the event of a fire, most flames contain large numbers of positive and negative charges from chemi-ionization, which generates an "ionic wind" by Lorentz forces through the applied electric fields. Using these ionic winds, an experimental study was performed to artificially control the fire smoke caused by burning paper and styrofoam, which are commonly used as insulation materials in general buildings and ships. The experiments showed that a fire smoke could be artificially controlled by applying a DC voltage in excess of ±5 kV and that relatively effective control was possible by applying a negative voltage rather than a positive voltage.

Topographic Variability during Typhoon Events in Udo Rhodoliths Beach, Jeju Island, South Korea (제주 우도 홍조단괴해빈의 태풍 시기 지형변화)

  • Yoon, Woo-Seok;Yoon, Seok-Hoon;Moon, Jae-Hong;Hong, Ji-Seok
    • Ocean and Polar Research
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    • v.43 no.4
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    • pp.307-320
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    • 2021
  • Udo Rhodolith Beach is a small-scale, mixed sand-and-gravel beach embayed on the N-S trending rocky coast of Udo, Jeju Island, South Korea. This study analyzes the short-term topographic changes of the beach during the extreme storm conditions of four typhoons from 2016 to 2020: Chaba (2016), Soulik (2018), Lingling (2019), and Maysak (2020). The analysis uses the topographic data of terrestrial LiDAR scanning and drone photogrammetry, aided by weather and oceanographic datasets of wind, wave, current and tide. The analysis suggests two contrasting features of alongshore topographic change depending on the typhoon pathway, although the intensity and duration of the storm conditions differed in each case. During the Soulik and Lingling events, which moved northward following the western sea of the Jeju Island, the northern part of the beach accreted while the southern part eroded. In contrast, the Chaba and Maysak events passed over the eastern sea of Jeju Island. The central part of the beach was then significantly eroded while sediments accumulated mainly at the northern and southern ends of the beach. Based on the wave and current measurements in the nearshore zone and computer simulations of the wave field, it was inferred that the observed topographic change of the beach after the storm events is related to the directions of the wind-driven current and wave propagation in the nearshore zone. The dominant direction of water movement was southeastward and northeastward when the typhoon pathway lay to the east or west of Jeju Island, respectively. As these enhanced waves and currents approached obliquely to the N-S trending coastline, the beach sediments were reworked and transported southward or northward mainly by longshore currents, which likely acts as a major control mechanism regarding alongshore topographic change with respect to Udo Rhodolith Beach. In contrast to the topographic change, the subaerial volume of the beach overall increased after all storms except for Maysak. The volume increase was attributed to the enhanced transport of onshore sediment under the combined effect of storm-induced long periodic waves and a strong residual component of the near-bottom current. In the Maysak event, the raised sea level during the spring tide probably enhanced the backshore erosion by storm waves, eventually causing sediment loss to the inland area.

A Review of Korean Medical Pathogenesis, Pattern Identification, Treatment Principle and Herbal Medicines for Allergic Conjunctivitis in Pediatric Patients (소아 알레르기 결막염의 한의학적 병인, 변증, 치법 및 한약재 선택에 대한 문헌적 고찰)

  • Kim, Ye Ji;Seo, Hae Sun;Park, Yong Seok;Park, Sul Gi;Lee, Sun Haeng;Lee, Jin Yong
    • The Journal of Pediatrics of Korean Medicine
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    • v.35 no.2
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    • pp.21-36
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    • 2021
  • Objectives We aimed to understand etiology, pattern differentiation, treatment principle, and the role of selected herbs in the treatment of Korean herbal medicine for allergic conjunctivitis (AC) in children. Methods We searched relevant literature published up to February 20, 2021 through CNKI, using search formula of (SU= '結膜炎'+'conjunctivitis') AND (SU='儿童'+'小儿'+'少儿'+'幼年') AND (SU='治療'+'中医治療'+'中藥'+'中医藥'+'顆粒'+'胶囊'+'自擬'+'湯'+'丸'+'散'+'方'). Results Among 81 searched studies, 9 randomized controlled trials and 1 case report were selected and analyzed. In all studies included, the efficacy of herbal treatment for AC was confirmed, and there was no evidence that herbal medicine treatment has higher risk of developing side effects compared to conventional eye drop treatment. As an etiology, wind (風邪) was observed the most frequently, and Saposhnikoviae Radix (防風) and Schizonepetae Spica (荊芥) were in frequent use to dispel wind (祛風). As visceral pattern identification, spleen (脾) and lung (肺) were two important keywords, and spleen deficiency (脾虛), dampness-heat in the spleen and stomach (脾胃濕熱), lung qi deficiency (肺氣虛) were main pathologic mechanisms. Else, treatments related to liver (肝) and removing dampness-heat (濕熱) were mentioned next. Conclusions This study is significant in that AC in children, which has a lack of research compared to other allergic diseases, has been studied in the contents of Korean medicine and laid foundation that can be used as basic data in the actual clinical field. Based on this study, it is hoped that clinical data of Korean herbal medicine treatment for childhood AC will be further accumulated.

Experimental Study on Aerodynamic Performance and Wake Characteristics of the Small Ducted Fan for VTOL UAV (수직 이착륙 무인기용 소형 덕티드팬의 공력성능 및 후류특성에 관한 실험적 연구)

  • Shin, Soo-Hee;Lee, Seung-Hun;Kim, Yang-Won;Cho, Tae-Hwan
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.1
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    • pp.1-12
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    • 2022
  • Wind tunnel test for a small scale electric ducted fan with a 104mm diameter was conducted to analyze the aerodynamic characteristics when it was used as a propulsion system of tilt-propeller UAV. Experimental conditions were derived from flight conditions of a sub-scaled OPPAV. Forces and moments of the ducted fan model were measured by a 6-axis balance and 3-dimensional wake vectors which could induce an aerodynamic influence in the vehicle were measured by 5-hole probes. Thrust and torque on hover and cruise conditions were measured and analyzed to drive out the operating conditions when it was applied in the sub-scaled OPPAV. On transition conditions, thrust keep its value with tilt angle variation below 40° and increase after that. But, sideforce increase constantly until 75°. The maximum axial velocity in the wake on hover and cruise conditions was around 60m/s and tangential velocity was around 12m/s. The position of the maximum axial velocity and vortex center move off the fan rotation center line as the tilt angle increases.

Prediction of Beach Profile Change Using Machine Learning Technique (머신러닝을 이용한 해빈단면 변화 예측)

  • Shim, Kyu Tae;Cho, Byung Sun;Kim, Kyu Han
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.42 no.5
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    • pp.639-650
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    • 2022
  • In areas where large-scale sediment transport occurs, it is important to apply appropriate countermeasure method because the phenomenon tends to accelerate by time duration. Among the various countermeasure methods applied so far, beach nourishment needs to be reviewed as an erosion prevention measure because the erosion pattern is mitigated and environmentally friendly depending on the particle size. In the case of beach nourishment. a detailed review is required to determine the size, range, etc., of an appropriate particle diameter. In this study, we investigated the characteristics of the related topographic change using the change in the particle size of nourishment materials, the application of partial area, and the condition under the coexistence of waves and wind as variables because those factors are hard to be analyzed and interpreted within results and limitation of that the existing numerical models are not able to calculate and result out so that it is required that phenomenon or efforts are reviewed at the same time through physical model experiments, field monitoring and etc. So we attempt to reproduce the tendency of beach erosion and deposition and predict possible phenomena in the future using machine learning techniques for phenomena that it is not able to be interpreted by numerical models. we used the hydraulic experiment results for the training data, and the accuracy of the prediction results according to the change in the training method was simultaneously analyzed. As a result of the study it was found that topographic changes using machine learning tended to be similar to those of previous studies in short-term predictions, but we also found differences in the formation of scour and sandbars.

The Social-Spatial Relationship between Jeongeup Julpungryu and Daepungryu (정읍 줄풍류와 대풍류의 사회적·공간적 연관성)

  • Cho, Seog-Yeon
    • (The) Research of the performance art and culture
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    • no.39
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    • pp.775-800
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    • 2019
  • Jeongeup Pungnyu, which can be regarded as a foundation of Hyangje Julpungryu(;string ensemble in Honam Area) best reflects social-spatial characteristics of local Pungryu culture. The close relationship between Daepungryu(wind ensemble) and Julpungryu can be inferred from three points of view. First, Jeongeumun who participated as a musician in the beginning of Hyangje Julpungryu was good at not only performing musical instrument but also dancing. Jeongeumun did not stay in specific musical field. He performed Hyangje Julpungryu, made Daepungryu and used it as dancing music with musicians that participated in Julpungryu. That is why Julpungryu and Daepungryu are not completely separated music. Secondly, according to , Jung Hyungin, who followed the dance of Jeong Jae-Sun with Kim So-Ran, was the first Piri player who learned from Jeongeumun and played Yeongsanhoesang and Samhyeon-yukkak(;wind ensemble). That is, Jeongeup Julpungryu was formed by Jeongeumun and dancer Jung Hyung-in followed Julpungryu and Daepungryu. Based on these findings, it can be inferred that Jeongeup's Daepungryu is fundamentally closely related to Jungeup Julpungryu.

Research trends in seabird and marine fish migration: Focusing on tracking methods and previous studies (바닷새 및 해양어류의 이동 연구 동향: 위치추적 기법과 연구 사례를 중심으로)

  • Jin-Hwan Choi;Seongho Yun;Mi-Jin Hong;Ki-Ho Kang;Who-Seung Lee
    • Korean Journal of Environmental Biology
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    • v.40 no.1
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    • pp.25-53
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    • 2022
  • In this study, trends in research methods and topics of seabird and marine fish migration were examined. Based on the framework of existing animal migration studies, future research directions were proposed in relation to the migration of seabirds and fish. In terms of research methodology, with the development of science and technology, tracking techniques using radio telemetry, acoustic telemetry, RFID (radio-frequency identification), satellite tracking, and geolocators are widely used to study seabird and fish migration. Research is also conducted indirectly through a population survey and the analysis of substances in the body. Research contents are largely classified into extrinsic factors that affect migration(such as environmental variables and interspecific competition), intrinsic factors such as hormones, anthropogenic activities including fishery and offshore wind farm, and the effect of global climate change. In future studies, physiological factors that influence or cause migration and dispersal should be identified concerning intrinsic factors. For the analysis of migration ability, it is necessary to study effects of changes in the magnetic field on the migration ability of seabirds and fish, interspecific differences in spatiotemporal migration ability, and factors that influence the migration success rate. Regarding extrinsic factors, research studies on effects of anthropogenic disturbances such as fishery and offshore wind farm and global climate change on the migration and dispersal patterns of marine animals are needed. Finally, integrated studies on the migration of seabirds and fish directly or indirectly affecting each other in various ecological aspects are required.