• Title/Summary/Keyword: 수치적 접근

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Hierarchical Bayesian analysis for a forest stand volume (산림재적 추정을 위한 계층적 베이지안 분석)

  • Song, Se Ri;Park, Joowon;Kim, Yongku
    • Journal of the Korean Data and Information Science Society
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    • v.28 no.1
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    • pp.29-37
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    • 2017
  • It has gradually become important to estimate a forest stand volume utilizing LiDAR data. Recently, various statistical models including a linear regression model has been introduced to estimate a forest stand volume using LiDAR data. One of limitations of the current approaches is in that the accuracy of observed forest stand volume data, which is used as a response variable, is questionable unstable. To overcome this limitation, we consider a spatial structure for a forest stand volume. In this research, we propose a hierarchical model for applying a spatial structure to a forest stand volume. The proposed model is applied to the LiDAR data and the forest stand volume for Bonghwa, Gyeongsangbuk-do.

A Study of a Teaching and Learning Process of the Information and Communication Ethics Based on Creative Problem Solving Method (창의적 문제해결 과정 기반의 정보통신 윤리교육 교수-학습과정 연구)

  • Kwon, Jungin;Ahn, Seongjin
    • The Journal of Korean Association of Computer Education
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    • v.16 no.3
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    • pp.41-48
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    • 2013
  • It is not easy to find out well organized teaching and learning methodology as the adverse effects of the internet have made a lot of problems because we realize the importance of the information/cyber ethic education. In this paper, I suggest the teaching and learning process of the information/cyber ethic education as applying the creative problem solving process of the six-step model proposed by A. Osborn and S. Parnes. We divided fifth grade 54 elementary school students into two groups, a experimental group and a control group, and conducted the the teaching and learning experimental methods. The experimental group, conducted educational teaching and learning methods for information ethics education using creative problem solving process, got a better result compared to the other group. It must be one of the systematic approach to lead changes of learners'; recognition, focusing on the ethics problem-solving process.

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Evaluation of ECMWF subseasonal-to-seasonal (S2S) hydrometeorological forecast across Australia (호주에서의 ECMWF 계절내-계절 수문기상 예측치 평가)

  • Jongmin Park
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.268-268
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    • 2023
  • 전 지구적 급격한 기후변화로 인해 수문기상인자들의 비선형적 변동성이 발생함과 동시에 가뭄, 홍수와 같은 수재해의 발생빈도 및 강도가 증가하고 있는 추세이다. 이에 따라, 세계의 유수기관 (NASA, ESA 등)에서는 대기모형과 해양 모형의 결합 및 수치해석적 접근법을 활용하여 계절내-계절 (Subseasonal to seasonal; S2S) 예측치를 생산하여 제공하고 있다. 이에 따라, 본 연구에서는 European Centre for Medium-Range Weather Forecast (ECMWF)에서 산정되는 수문기상인자 (강수량, 증발산량 및 유출량)에 대한 정확도를 평가하고자 한다. 연구지역으로는 다양한 기후대 및 토지 피복으로 구성되어 있으며, El-Nino-Southern Oscillation (ENSO), Indian Ocean Diapole (IOD)와 같은 기후 현상이 빈번히 발생하는 호주지역을 대상으로 연구를 수행하였다. ECMWF S2S 자료에 대한 통계적 검증은 1) 지점 기반 관측치와 더불어 2) 물수지 모델 기반 수문 추정치 (The Australian Water Resources Assessment Landscape Model; AWRA-L)와 비교하였다. 연구 결과 S2S 강우 및 증발산량 산정치의 경우 비교적 짧은 예측기간(약 2주)에서 상대적으로 높은 상관관계 (R=0.5~0.6)와 낮은 편차 (강수량 = 0.10 mm/day, 증발산량 = 0.21 mm/day)를 나타내었다. 유출량의 경우, 강우 및 증발산량에 비해 상대적으로 낮은 정확도를 나타내었으며, 예측 기간이 길어짐에 따라 불확실성이 상당히 높아지는 것으로 확인되었다. 이는, S2S 계산과정에서 강우 및 증발산량 뿐만아니라 지표 유출로 도달하기 전까지의 수문기상인자들의 불확실성이 모두 모여 유출량의 불확실성이 높아진 것으로 확인할 수 있었다. 계절적 검증에서는, 강우 및 증발산량 모두 여름철에 높은 상관관계를 나타내었지만 불확실성은 상대적으로 큰 값을 나타내었다. 자세한 분석을 위해, 공간적인 불확실성을 분석해본 결과 ECMWF S2S가 매우 습윤하거나 건조한 지역에서 수문기상인자를 예측하는데 있어 한계성이 나타난 것을 확인하였다. 본 연구를 토대로, 추후 S2S 예측치에 대한 보정과 더불어 미래의 수재해 발생 위험도에 대한 정보를 획득하는데 적용될 수 있을 것으로 판단된다.

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Development of a quantification method for modelling the energy budget of water distribution system (상수관망 에너지 모의를 위한 정량화 분석기법 개발)

  • Choi, Doo Yong;Kim, Sanghyun;Kim, Kyoung-Pilc
    • Journal of Korea Water Resources Association
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    • v.55 no.spc1
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    • pp.1223-1234
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    • 2022
  • Efforts for reducing greenhouse gas emission coping with climate change have also been performed in the field of water and wastewater works. In particular, the technical development for reducing energy has been applied in operating water distribution system. The reduction of energy in water distribution system can be achieved by reducing structural loss induced by topographic variation and operational loss induced by leakage and friction. However, both analytical and numerical approaches for analyzing energy budget of water distribution system has been challengeable because energy components are affected by the complex interaction of affecting factors. This research drew mathematical equations for 5 types of state (hypothetical, ideal, leak-included ideal, leak-excluded real, and real), which depend on the assumptions of topographic variation, leakage, and friction. Furthermore, the derived equations are schematically illustrated and applied into simple water network. The suggested method makes water utilities quantify, classify, and evaluate the energy of water distribution system.

Effect of buoyancy and thermocapillarity on the melt motion and mass transfer for different aspect ratio of flow field in magnetic Czochralski crystal growth of silicon (Cusp 자장이 걸려있는 초크랄스키 실리콘 단결정성장에서 유동장의 종횡비에 따라 부력과 열모세관 현상이 용융물질의 유동과 물질전달에 미치는 영향)

  • 김창녕
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.10 no.3
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    • pp.177-184
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    • 2000
  • The effect of the buyancy and thermocapillarity for differnent aspect ratio of flow field on melt motion and mass transfer has been numerically investigated in magnetic Czochralski crystal growth of silicon. During the process of crystal growth, the melt depth of crucible reduces so the aspect ratio of flow field also reduces. Therefore the shape of magnetic field of the flow field changes and the flow pattern also changes significantly. Together with the melt flow which forms the Marangoni convection (or thermocapillary flow) that comes from the inside the flow field, a flow circulation is observed near the corner close both to the crucible wall and the free surface. Due to this circulation, buoyancy effect has been turned out to be local rather than global. As the aspect ratio decreases, the radial component of the magnetic field prevails compared with the axial component in the flow field. Under the influence of this magnetic field, the melt flow and the temperature distribution in a meridional plane tend to depend on the radial position. As the aspect ratio decreases, the temperature gradient near the edge of the crystal decreases yielding smaller thermocapillarity, and the oxygen concentration near the crystal and the oxygen incorporation rate also decrease.

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A Measurement Way of Seaport Efficiency and Ranking Using Fuzzy DEA: Average Index Transformation Model Approach (퍼지DEA에 의한 항만의 효율성 및 순위 측정방법: 평균지수변환모형 접근)

  • Park, Ro-Kyung
    • Journal of Korea Port Economic Association
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    • v.26 no.2
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    • pp.82-98
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    • 2010
  • The purpose of this paper is to suggest the efficiency measurement way of Korean seaport by using Average Index Transformation model of fuzzy DEA(Data Envelopment Analysis). Two inputs[cargo handling capacity, and berthing capacity], and outputs[cargo handling amount, and the number of ship calls] are used in 1995 and 2004 for 26 Korean seaports. Empirical main results are as follows: First, Tongyung, Gohyun, Okpo, and Sogcho Ports are efficient, and Yeasu Port shows the high efficiency level over 95% under input oriented CCR model. Gohyun and Sogcho Ports showed the most efficient score under average index transformation model. Okpo and Yeasu Ports increased their efficiency scores as the lamda(λ) values are up. The empirical results of fuzzy DEA average index transformation model for Wando, Yeasu, and Seoguipo ports showed that if the lamda values are higher, the efficiency scores are also higher. The main policy implication based on the findings of this study is that the management manager of Ministry of Land, Transport and Maritime Affairs in Korea should introduce the fuzzy DEA average index transformation model for deciding the size of inputs including the port investment amount and evaluating the port efficiency.

Analysis on Displacement Characteristics of Slow-Moving Landslide on a slope near road Using the Topographic Map and Airborne LiDAR (수치지형도와 항공 LiDAR를 이용한 도로인접 사면 땅밀림 발생지 변위 특성 분석)

  • Seo, Jun-Pyo;Kim, Ki-Dae;Woo, Choong-Shik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.5
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    • pp.27-35
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    • 2019
  • The purpose of this study is to analyze the displacement characteristics in slow-moving landslide area using digital elevation model and airborne LiDAR when unpredictable disaster such as slow-moving landslide occurred. We also aimed to provide basic data for establishing a rapid, reasonable and effective restoration plan. In this study, slow-moving landslide occurrence cracks were selected through the airborne LiDAR data, and the topographic changes and the scale of occurrence were quantitatively analyzed. As a result of the analysis, the study area showed horseshoe shape similar to the general form of slow-moving landslide occurrence in Korea, and the direction of movement was in the north direction. The total area of slow-moving landslide damage was estimated to about 2.5ha, length of landsldie scrap 327.3m, average width 19.3m, and average depth 8.6m. The slow-moving landslides did not occur on a large scale but occurred on the adjacent slope where roads were located, caused damage to retaining walls and roads. The field survey of slow-moving landslides was limited by accessibility and safety issues, but there was an advantage that accurate analysis was possible through the airborne LiDAR. However, because airborne LiDAR has costly disadvantages, it has proposed a technique to mount LiDAR on UAV for rapidity, long-term monitoring. In a slow-moving landslide damage area, information such as direction of movement of cracks and change of scale should be acquired continuously to be used in restoration planning and prevention of damage.

EU FP6 Welfare Quality® Poultry Assessment Systems

  • Butterworth, A.
    • Korean Journal of Poultry Science
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    • v.36 no.3
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    • pp.239-246
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    • 2009
  • Animal welfare is of considerable importance to European consumers and citizens, this being most recently confirmed in EU barometer studies. Researchers and others have long proposed that animal-based measures (measures taken on animals, e.g. their health and behaviour) can provide a valid indicator of animal welfare; since welfare is a characteristic of the individual animal. Therefore, a welfare assessment can be essentially based on animal-based measures, but with use of resource measures to provide the capacity to assess 'risk factors'. The first goal of this project was to develop a welfare monitoring system that enables assessment of welfare status through standardised conversion of welfare measures into accessible and understandable information. The acquired information on one hand provides feedback to animal unit managers about the welfare status of their animals, and on the other, information on the welfare status of animal-related products for consumers and retailers. The second goal of Welfare $Quality^{(R)}$ was to improve animal welfare by minimising the occurrence of harmful behavioural and physiological states, improving human-animal relationships, and providing animals with safe and stimulating environments. The different measurable aspects of welfare to be covered are turned into welfare criteria. The criteria reflect what is meaningful to animals as understood by animal welfare science. Once all the measures have been performed on an animal unit, a bottom-up approach is followed to produce an overall assessment of animal welfare on that particular unit: first the data collected (i.e. values obtained for the different measures on the animal unit) are combined to calculate criterion-scores; then criterion-scores are combined to calculate principle-scores; and finally the animal unit is assigned to a welfare category according to the principle-scores it obtained.

Propagation of Tsunamis Generated by Seabed Motion with Time-History and Spatial-Distribution: An Analytical Approach (시간이력 및 공간분포를 지닌 지반운동에 의한 지진해일 발생 및 전파: 해석적 접근)

  • Jung, Taehwa;Son, Sangyoung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.30 no.6
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    • pp.263-269
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    • 2018
  • Changes in water depth caused by underwater earthquakes and landslides cause sea surface undulations, which in turn propagate to the coast and result in significant damage as wave heights normally increase due to the wave shoaling process. Various types of numerical models have been developed to simulate the generation and propagation of tsunami waves. Most of tsunami models determine the initial surface of the water based on the assumption that the movement of the seabed is immediately and identically transmitted to the sea surface. However, this approach does not take into account the characteristics of underwater earthquakes that occur with time history and spatial variation. Thus, such an incomplete description on the initial generation of tsunami waves is totally reflected in the error during the simulation. In this study, the analytical solution proposed by Hammack (1973) was applied in the tsunami model in order to simulate the generation of initial water surface elevation by the change of water depth with time history and its propagation. The developed solution is expected to identify the relationship among various type of seabed motions, initial surface undulations, and wave speeds of elevated water surfaces.

Assessment of Soil Loss in Irrigation Reservoir based on GIS (GIS를 이용한 관개용 저수지의 토사유실량 산정에 관한 연구)

  • Park, Woo Sik;Hong, Soon Heon;Ahn, Chang Hwan;Choi, Hyun
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.31 no.6_1
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    • pp.439-446
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    • 2013
  • This paper is about assessment of soil loss in irrigation reservoir based on GIS. Natural disaster caused by soil loss whose natural incidence has been rapidly reduced due to successful tree planting campaign shows high potential risk, since the latest localized heavy rain resulted from extreme weather event and artificial land development acts as direct factors for land disaster. To prevent it, various techniques and technologies have been used to predict effect of soil loss. However, reliability of techniques and technologies to predict its effect precisely is relatively low so far because the natural disaster by soil loss is taken place by complicated interaction between possible factors and direct factors. Geospatial approach is essential to examine these interactions. In this regard, this study will provide detailed plan to improve prediction reliability for soil loss of irrigation reservoir, using GIS that has Hydrologic -Topographical parameter and digital map as its input parameters.