• 제목/요약/키워드: Hypothetical Distance

검색결과 26건 처리시간 0.023초

바람장의 공간적.시간적 해상도가 누출물질 확산에 미치는 영향 (Effects of Spatio-Temporal Resolution of Diagnostic Wind Field on the Dispersion of Released Substance)

  • 김영성
    • 한국대기환경학회지
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    • 제16권4호
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    • pp.327-338
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    • 2000
  • complexity in atmospheric environment coupled with shoreline and complex terrain often causes local variations of meteorology that are distinct from those representative over larger surrounding area, These kinds of local variations are less significant in usual long-term environmental impact analyses dealing with continuous plume. The variations could however be crucial in predicting dispersion of toxic substance released in a relatively small area for a short duration. In the present paper the effects of spatial and temporal resolution of diagnostic wind field on the dispersion of the released substance are investigated by using a puff model. A hypothetical release scenario assumes that a substance is released from a location in the Yochon Industrial Estate and passively dispersed within a few-kilometer distance for an hour. The results show that diagnostic analysis could resolve more spatial variations to some extent by employing smaller grid size. The peak concentrations and puff trajectories obtained from spatially -and/or tmeporally -varing diagnostic wind field are found appreciably different from those obtained from uniform wind field. Attention to high-resolution wind field in the both spatial and temporal spaces is called in the consequence analysis of toxic substance release.

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국가대표 크로스컨트리 스키 선수들의 Start & Finish 구간에 대한 Double poling 기술의 운동학적 분석 (The Kinematic Analysis about Double Poling Technique of National Cross-Country Skiers at Start & Finish Phases)

  • 최슬비;류재균
    • 한국운동역학회지
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    • 제22권1호
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    • pp.95-104
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    • 2012
  • The purpose of this study targeted to national cross-country skiers representatives was to implement hypothetical experiment on their patterns of the movements and analysis on kinematic variables occurred while double polling was conducted between starting and finishing phase of 56 meters. Furthermore, it aimed to provide a set of quantitative data to illustrate how to improve one's skill and performance of sprint. In our experiments, we conducted 3-dimension analysis of cycle characteristics, joint angle(hip, knee and elbow), and pole angle. The results showed that at the starting phase, the players did not show a significant difference in attributes of time and distance. In heat 1 where elbow angle and polling starts, the pole angle was noticeably high in heat 1. At the finishing phase, there was a considerable distinction with a high frequency in performing a short polling time and high speed in heat 3. The players showed large extension between the flexion and of the hip angle which indicates high contribution given from the movement of lower body(hip, knee).

학교강당의 평면적 특징에 따른 대피효율에 관한 연구 (Evacuation Efficiency on School Auditorium Floor Layout)

  • 권준범;김덕수;김길채
    • 교육시설 논문지
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    • 제24권2호
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    • pp.3-10
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    • 2017
  • This study compared evacuation effectiveness between the conventional school auditorium plan and a suggested hypothetical plan that was generated by a mathematical model, which is commonly applied in the field of industrial engineering. Recent school buildings became much more complicated in floor planning due to new social needs and modern curriculum than the old days. Nevertheless, architect's approach to floor composition in terms of fire emergency evacuation planning, still has no relation to optimized effective but relies more on an conventional school planning. Therefore, since school buildings are much more likely to be exposed to any fire related events than any other building types, emergency exit effectiveness based on spatial composition has to be seriously evaluated with a scientific method. The algorithm, which acquires the number of persons in each spatial type(node) per floor and the minimum physical distance between spatial types(arc), can propose the most optimized spatial layout per floor regarding emergency evacuation event. Consequently, this study evaluated school's fire exit effectiveness focusing on auditorium area with the scientific tool and suggested the most reliable spatial layout regarding possibile emergency evacuation event.

초등학교 층별 구성과 비상시 대피효율성의 관계 (Effective Evacuation based on Elementary School's Floor Layout)

  • 권준범;김덕수;김길채
    • 교육시설 논문지
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    • 제23권3호
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    • pp.3-10
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    • 2016
  • This study compared evacuation effectiveness between the conventional school floor plan and a suggested hypothetical floor plan that was generated by a mathematical model that is commonly applied in the field of industrial engineering. Recent school buildings became much more complicated in floor planning due to the new educational system and modern curriculum than the old days. Nevertheless, architect's approach to floor composition in terms of fire emergency evacuation planning, still has no relation to optimized effective but relies more on a conventional school planning. Therefore, since elementary school buildings are much more likely to be exposed to any fire related events than middle school or high-school, emergency exit effectiveness based on spatial composition has to be seriously evaluated with a scientific method. The algorithm, which acquires the number of persons in each spatial type (node) per floor and the minimum physical distance between spatial types (arc), can propose the most optimized spatial compositing per floor regarding emergency evacuation event. Consequently, this study evaluated elementary school's fire exit effectiveness with the scientific tool and suggested the most reliable spatial composition per floor regarding possibile emergency evacuation event.

Intergalactic Magnetic Field and Arrival Direction of Ultra-High-Energy Iron Nuclei

  • 류동수;강혜성
    • 천문학회보
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    • 제37권2호
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    • pp.78.2-78.2
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    • 2012
  • We have studied how the intergalactic magnetic field (IGMF) affects the propagation of super-GZK iron nuclei that originate from extragalactic sources within the local GZK sphere. Toward this end, we set up hypothetical sources of ultra-high-energy cosmic-rays (UHECRs), virtual observers, and the magnetized cosmic web in a model universe constructed from cosmological structure formation simulations. We then arranged a set of reference objects at high density region to represent astronomical objects formed in the large scale structure (LSS). With our model IGMF, the paths of UHE iron nuclei are deflected on average by about 70 degrees, which might indicate a nearly isotropic distribution of arrival directions. However, the separation angle between the arrival directions and the nearest reference object on the LSS is only ~6 degrees, which is twice the mean distance to the nearest neighbors among the reference objects. This means that the positional correlation of observed UHE iron events with their true sources would be erased by the IGMF, but the correlation with the LSS itself is to be sustained. We discuss implications of our findings for correlations studies of real UHECR events.

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수도권 산업단지(클러스터)의 광역권 내부 및 외부 연계구조 분석 (An Analysis on the Linkage Structure of Industrial Complexes(Clusters) in the Internal and External Capital Region)

  • 구양미;남기범;박삼옥
    • 한국경제지리학회지
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    • 제13권2호
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    • pp.181-195
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    • 2010
  • 광역경제권 정책에 따라 산업단지 정책도 광역권 단위에서 연계구조를 구축하려는 방향으로 논의가 진행되고 있다. 본 분석의 목적은 수도권 산업단지들을 대상으로 산업단지간 연계구조를 도출하는 것이다. 먼저 수도권 산업단지 입주업체 설문조사를 실시하여 광역권 내의 지역간 연계 현황을 파악하였다. 산업단지의 업종별 종사자수 자료를 이용하여 산업단지간 구조유사척도를 계산하고, 수도권 내부와 외부 산업단지의 유사성을 살펴보았다. 또한 산업단지간 거리, 업종별 비율, 입지계수 등의 지표를 종합적으로 판단하여 산업단지 허브-스포크 연계구조(안)를 도출하였다.

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계절양수가 하천건천화에 미치는 영향 (Impacts of Seasonal Pumping on Stream Depletion)

  • 이현주;구민호;임진실;유병호;김용철
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제21권1호
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    • pp.61-71
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    • 2016
  • Visual MODFLOW was used for quantifying stream-aquifer interactions caused by seasonal groundwater pumping. A hypothetical conceptual model was assumed to represent a stream-aquifer system commonly found in Korea. The model considered a two-layered aquifer with the upper alluvium and the lower bedrock and a stream showing seasonal water level fluctuations. Our results show that seasonal variation of the stream depletion rate (SDR) as well as the groundwater depletion depends on the stream depletion factor (SDF), which is determined by aquifer parameters and the distance from the pumping well to the stream. For pumping wells with large SDF, groundwater was considerably depleted for a long time of years and the streamflow decreased throughout the whole year. The impacts of return flow were also examined by recalculating SDR with an assumed ratio of immediate irrigation return flow to the stream. Return flow over 50% of pumping rate could increase the streamflow during the period of seasonal pumping. The model also showed that SDR was affected by both the conductance between the aquifer and the stream bed and screen depths of the pumping well. Our results can be used for preliminary assessment of water budget analysis aimed to plan an integrated management of water resources in riparian areas threatened by heavy pumping.

Damage and vibrations of nuclear power plant buildings subjected to aircraft crash part II: Numerical simulations

  • Li, Z.R.;Li, Z.C.;Dong, Z.F.;Huang, T.;Lu, Y.G.;Rong, J.L.;Wu, H.
    • Nuclear Engineering and Technology
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    • 제53권9호
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    • pp.3085-3099
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    • 2021
  • Investigations of large commercial aircraft impact effect on nuclear power plant (NPP) buildings have been drawing extensive attentions, particularly after the 9/11 event, and this paper aims to numerically assess the damage and vibrations of NPP buildings subjected to aircrafts crash. In Part I of present paper, two shots of reduce-scaled model test of aircraft impact on NPP were conducted based on the large rocket sled loading test platform. In the present part, the numerical simulations of both scaled and prototype aircraft impact on NPP buildings are further performed by adopting the commercial program LS-DYNA. Firstly, the refined finite element (FE) models of both scaled aircraft and NPP models in Part I are established, and the model impact test is numerically simulated. The validities of the adopted numerical algorithm, constitutive model and the corresponding parameters are verified based on the experimental NPP model damages and accelerations. Then, the refined simulations of prototype A380 aircraft impact on a hypothetical NPP building are further carried out. It indicates that the NPP building can totally withstand the impact of A380 at a velocity of 150 m/s, while the accompanied intensive vibrations may still lead to different levels of damage on the nuclear related equipment. Referring to the guideline NEI07-13, a maximum acceleration contour is plotted and the shock damage propagation distances under aircraft impact are assessed, which indicates that the nuclear equipment located within 11.5 m from the impact point may endure malfunction. Finally, by respectively considering the rigid and deformable impacts mainly induced by aircraft engine and fuselage, an improved Riera function is proposed to predict the impact force of aircraft A380.

교통수단의 토지소모 효율성 비교분석 (Evaluation and Comparison of Land Consumption Efficiencies of Transportation Modes)

  • 신용은
    • 대한토목학회논문집
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    • 제28권6D호
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    • pp.801-807
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    • 2008
  • 본 연구는 시간-면적 방법론을 적용하여 도시교통수단의 토지소모 효율성을 비교분석하고자 하였다. 도시의 주요 교통수단을 대상으로 그간의 연구와 달리 각 수단에 적합한 교통조건과 운행여건을 고려한 토지소모효율성 산정식을 도출하였고, 도출된 식을 이용하여 각 수단별 1km 통행시의 인당 시간-면적 소모량을 계산하여 비교하였다. 또한 산정식을 이용하여 소모량과 운행속도와의 관계를 분석하여 각 수단의 소모량의 범위를 비교하였으며, 주차에 의한 시간-면적 소모량을 명확히 제시하기 위해 외곽으로부터 도심으로 통행하는 통근자의 가상 왕복통행을 가정하여 수단별 통행에 따른 총 시간-면적소모량을 비교분석하였다. 연구의 결과, 이용시설에 상관없이 승용차 이용자가 가장 소모량이 많은 것으로 나타났고, 도시철도를 포함한 대중교통수단의 효율성이 우수한 것으로 나타났다. 예상과는 달리 도보와 자전거는 높은 소모량을 보였다. 그럼에도 불구하고 단거리 통행시 버스를 대체할 수 있는 수단으로 나타났다.

천문 수업에 대한 초등 교사의 주제-특이적 PCK 발달과정 탐색 -태양계 행성의 크기와 거리 주제를 중심으로- (Exploring Topic-Specific PCK Progression for Elementary Teachers Instruction of Astronomy: Focusing on the Topic of Planet Size and Distance in Solar System)

  • 이기영;이정아
    • 한국과학교육학회지
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    • 제36권4호
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    • pp.629-641
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    • 2016
  • 교사의 수업 전문성이 시간에 따라 어떻게 발달하는지 이해하는 것은 유효적절한 지원을 제공하는데 있어 기초가 된다. 이와 같은 전제에 근거하여 이 연구에서는 초등 교사의 천문 수업 중 행성의 크기와 거리에 대해 주제-특이적 PCK 발달과정을 탐색하고자 하였다. 교사의 PCK가 시간에 따라 어떻게 발달하는지 파악하기 위해 이 연구에서는 학생의 학습발달과정(learning progressions; 이하 LPs)이라는 개념틀을 적용하였다. LPs와 마찬가지로 교사의 수업전문성 발달 또한 초보에서 적응적 전문가로 발달하는 가설적인 경로로 기술될 수 있다는 것이다. 이 연구를 위해 서울, 강원, 광주 지역 소재 6개 초등학교 5학년 교사 8명이 참여하였으며, 2013년과 2014년에 걸쳐 '태양계와 별' 단원 '의 수업을 녹화하였다. 녹화된 수업에서 참여 교사의 주제-특이적 PCK를 문서화하기 위해 수업 분석틀을 개발하여 적용하였다. 이 연구는 천문 수업에서 행성의 크기와 거리 주제에 대한 초등 교사들의 PCK 발달과정을 개발하는 것이 주된 목적이긴 하지만, 이와 더불어 개발된 PCK 발달과정의 타당성 근거를 확보하는 것도 또 하나의 중요한 목적이므로 2013년과 2014년에 중복 참여한 4명 교사들의 PCK 변화를 종단적으로 추적하였다. 종단 연구에 참여한 교사들은 연구자들과 함께 적응적 교수활동을 개발하는 4주간의 사전 모임에 참여하였다. 이 연구를 통해 3개 PCK 요소(교육과정, 교수전략, 학생평가)에 대해 4~5수준의 발달과정을 개발하였으며, 1개 천문학적 사고 요소(시스템 사고)에 대해 4수준의 발달 과정을 개발하였다. 참여 교사들은 PCK 요소별로 서로 다른 발달 수준을 나타내었으며, 적응적 교수활동 개발 및 적용을 통해 PCK 수준이 다양한 경로로 변화되는 것으로 나타났다. 이 연구는 특정 주제에 대한 과학 교사의 PCK 발달 수준에 적절한 수업 스캐폴딩을 촉진하는데 있어 경험적인 근거를 제시하였다는 점에서 의미를 가진다.