• Title/Summary/Keyword: 공간 불확실성

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Analyzing the Ambiguities of Spatial Operators in OpenGIS (OpenGIS공간 연산자 구현시의 모호성 분석)

  • 정소영;홍은지;유석인
    • Proceedings of the Korean Information Science Society Conference
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    • 1998.10b
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    • pp.105-107
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    • 1998
  • 지리 정보 시스템(Geographic Information System, GIS)에서 이용되는 공간 데이터 모델의 표준 규약인 OpenGIS 명세서(specification)를 이용하여 공간 관계 연산자(Spatial Relational Operator)를 구현하고자 할 때 세부적인 의미가 명확하게 이해되지 않는 경우가 많다. 본 논문에서는 각각의 공간 객체들의 내부(Interior), 외부(Exterior), 경계(Boundary)의 정의를 이용하여 실제로 공간 연산자를 구현할 때 고려해야 하는 의미의 불확실성에 대해 고찰하여, 세부적 의미를 밝힌다.

A Study on the Probabilistic Analysis Method Considering Spatial Variability of Soil Properties (지반의 공간적 변동성을 고려한 확률론적 해석기법에 관한 연구)

  • Cho, Sung-Eun;Park, Hyung-Choon
    • Journal of the Korean Geotechnical Society
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    • v.24 no.8
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    • pp.111-123
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    • 2008
  • Geotechnical engineering problems are characterized by many sources of uncertainty. Some of these sources are connected to the uncertainties of soil properties involved in the analysis. In this paper, a numerical procedure for a probabilistic analysis that considers the spatial variability of soil properties is presented to study the response of spatially random soil. The approach integrates a commercial finite difference method and random field theory into the framework of a probabilistic analysis. Two-dimensional non-Gaussian random fields are generated based on a Karhunen-$Lo{\grave{e}}ve$ expansion in a fashion consistent with a specified marginal distribution function and an autocorrelation function. A Monte Carlo simulation is then used to determine the statistical response based on the random fields. A series of analyses were performed to study the effects of uncertainty due to the spatial heterogeneity on the settlement and bearing capacity of a rough strip footing. The simulations provide insight into the application of uncertainty treatment to the geotechnical problem and show the importance of the spatial variability of soil properties with regard to the outcome of a probabilistic assessment.

A Study on the Processing of Imprecision Data by Rough Sets (러프집합에 의한 불완전 데이터의 처리에 관한 연구)

  • 정구범;김두완;정환묵
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1998.03a
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    • pp.11-15
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    • 1998
  • 일반적으로 러프집합은 지식베이스 시스템에서 근사공간을 이용한 불확실한 데이터의 분류, 추론 및 의사결정 등에 사용된다. 지식베이스 시스템의 데이터 중에서 연속적인 구간 특성을 갖는 정량적 속성값이 불연속적일 때 중복 또는 불일치 등의 불확실성이 발생된다. 본 논문은 러프집합의 정량적 속성값들의 정성적 속성으로 변환시킬 때 식별 불가능 영역에 있는 정량적 속성값들을 명확한 경계를 갖는 보조구간으로 분리하여 불확실성을 제거함으로써 러프집합의 분류능력을 향상시키는 방법을 제안한다.

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Local Uncertainty of Thickness of Consolidation Layer for Songdo New City (송도신도시 압밀층 두께의 국부적 불확실성 평가)

  • Kim, Dong-Hee;Ryu, Dong-Woo;Chae, Young-Ho;Lee, Woo-Jin
    • Journal of the Korean Geotechnical Society
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    • v.28 no.1
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    • pp.17-27
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    • 2012
  • Since geologic data are often sampled at sparse locations, it is important not only to predict attribute values at unsampled locations but also to assess the uncertainty attached to the prediction. In this study the assessment of the local uncertainty of prediction for the thickness of the consolidation layer was performed by using the indicator approach. A conditional cumulative distribution function (ccdf) was first modeled, and then E-type estimates and the conditional variance were computed for the spatial distribution of the thickness of the consolidation layer. These results could be used to estimate the spatial distribution of secondary compression and to assess the local uncertainty of secondary compression for Songdo New City.

Two-dimensional Inundation Analysis using Stochastic Rainfall Variation in Nam-River Basin (남강유역에서의 추계학적 강우변동 생성기법과 연계한 2차원 침수해석)

  • Ahn, Ki-Hong;Lee, Jin-Young;Han, Kun-Yeun;Cho, Wan-Hee
    • Proceedings of the Korea Water Resources Association Conference
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    • 2010.05a
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    • pp.610-614
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    • 2010
  • 지구온난화에 따른 이상기후 현상으로 불확실성에 대한 고려가 더욱 중요해진 지금 설계빈도의 무조건적인 상향조정에 의존하기보다는 추계학적 방법을 도입한 수문량의 확충 및 매개변수의 불확실성을 고려하기 위한 연구가 활발히 진행중이다. 본 연구에서는 강우발생의 불확실성을 반영하여 제내지에서의 침수 범위를 GIS상에서 검토하기 위해 log-ratio 방법, Johnson 시스템, 직교변환을 활용한 다변량 Monte Carlo 기법으로 추계학적 시간에 따른 강우변동을 생성하였다. 생성된 강우변동 결과를 토대로 수문분석, 홍수위 분석 등을 실시하고 FLUMEN 모형을 적용하여 해당유역에 대한 홍수범람시 침수범위를 산정하였다. 본 연구결과는 실제 강우의 불확실성을 반영하고 있어 시 공간적 강우특성이 반영된 유역별 주민대피지도, 홍수위험지도 등을 제작하는데 활용될 수 있을 것으로 기대된다.

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A Grouping Technique for Efficient Search of Uncertain Data in Ubiquitous Sensor Networks (유비쿼터스 센서 네트워크에서 불확실한 데이타의 효율적 검색을 위한 그룹화 기법)

  • Kim, Dong-Oh;Hong, Dong-Suk;Han, Ki-Joon
    • 한국공간정보시스템학회:학술대회논문집
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    • 2007.06a
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    • pp.65-70
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    • 2007
  • 유비쿼터스 센서 네트워크 관련 기술이 급속히 발전하고 센서가 여러 분야에서 활용됨에 따라 센싱되는 데이타를 효율적으로 관리하기 위한 연구가 활발히 진행되고 있다. 일반적으로 유비쿼터스 센서 네트워크에서 센싱되는 데이타는 계통적 오차와 측정 방법의 부적합 등으로 인한 불확실성을 가지며, 또한 센싱하는 환경 및 제약으로 인해 데이터가 유사하거나 반복되는 제한성을 가진다. 그러나 기존의 연구들은 센싱되는 데이타의 이러한 특성을 고려하지 못함으로 인해 검색이 비효율적이다. 따라서, 본 논문에서는 불확실한 데이타를 고려한 기존의 인덱스를 확장하여 유비쿼터스 센서 네트워크에서 센싱되는 데이타 중 제한성을 가지는 데이타를 그룹화함으로써 효율적인 검색을 지원하는 그룹화 기법을 제시한다. 본 논문은 센싱된 데이타를 그룹화하는 기법으로써 처음에 그룹으로 설정된 영역을 이용해 그룹화하는 최초 그룹화 기법, 한 그룹 내에 최대한 많은 데이타를 그룹화하는 최적 그룹화 기법, 센싱된 데이타를 최대한 근접하게 그룹화하는 최근접 그룹화 기법을 제시한다. 마지막으로, 성능 평가를 통해 본 논문에서 제시한 그룹화 기법을 이용한 인덱스에 대한 검색 성능의 우수성을 입증한다.

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Investigating the scaling effect of the nonlinear response to precipitation forcing in a physically based hydrologic model (강우자료의 스케일 효과가 비선형수문반응에 미치는 영향)

  • Oh, Nam-Sun;Lee, K.
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.149-153
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    • 2006
  • Precipitation is the most important component and critical to the study of water and energy cycle. This study investigates the propagation of precipitation retrieval uncertainty in the simulation of hydrologic variables for varying spatial resolution on two different vegetation cover. We explore two remotely sensed rain retrievals (space-borne IR-only and radar rainfall) and three spatial grid resolutions. An offline Community Land Model (CLM) was forced with in situ meteorological data In turn, radar rainfall is replaced by the satellite rain estimates at coarser resolution $(0.25^{\circ},\;0.5^{\circ}\;and\;1^{\circ})$ to determine their probable impact on model predictions. Results show how uncertainty of precipitation measurement affects the spatial variability of model output in various modelling scales. The study provides some intuition on the uncertainty of hydrologic prediction via interaction between the land surface and near atmosphere fluxes in the modelling approach.

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Probabilistic Analysis of Liquefaction Induced Settlement Considering the Spatial Variability of Soils (지반의 공간변동성을 고려한 액상화에 의한 침하량의 확률론적 해석)

  • Bong, Tae-Ho;Kim, Byoung-Il
    • Journal of the Korean Geotechnical Society
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    • v.33 no.5
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    • pp.25-35
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    • 2017
  • Liquefaction is one of the major seismic damage, and several methods have been developed to evaluate the possibility of liquefaction. Recently, a probabilistic approach has been studied to overcome the drawback of deterministic approaches, and to consider the uncertainties of soil properties. In this study, the spatial variability of cone penetration resistance was evaluated using CPT data from three locations having different variability characteristics to perform the probabilistic analysis considering the spatial variability of soil properties. Then the random fields of cone penetration resistance considering the spatial variability of each point were generated, and a probabilistic analysis of liquefaction induced settlement was carried out through CPT-based liquefaction evaluation method. As a result, the uncertainty of soil properties can be overestimated when the spatial variability is not considered, and significant probabilistic differences can occur up to about 30% depending on the allowable settlement.

Algorithm for Topological Relationship On an Indeterminate Spatiotemporal Object (불확실한 시공간 객체에 관한 위상 관계 알고리즘)

  • Ji, Jeong-Hui;Kim, Dae-Jung;Ryu, Keun-Ho
    • The KIPS Transactions:PartD
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    • v.10D no.6
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    • pp.873-884
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    • 2003
  • So far, significant achievements have been studied on the development of models for spatial and spatiotemporal objects with indeterminate boundaries which are found in many applications for geographic analysis and image understanding. Therefore, in this paper we propose the spatiotemporal data model which is applicable for spatial and spatiotemporal objects with uncertainty. Based on this model, we defined topological relationships among the indeterminate spatiotemporal objects and designed the algorithm for the operations. For compatibility with existing spatial models, the proposed model has been designed by extending the spatiotemporal object model which is based on the open GIS specification. We defined indeterminate spatial objects, such as the objects whose position and the shape change discretely over time, and the objects whose shape changes continuously as well as the position. We defined topological relationships among these objects using the extended 9-IM. The proposed model can be efficiently applied to the management systems of natural resource data, westher information, geographic information. and so on.

Uncertainty Analysis of the Optical Smoke Density Measurement through the Doorway in a Compartment Fire (구획화재의 출입구를 통한 광학적 연기밀도 측정의 불확실성 해석)

  • Kim, Sung-Chan
    • Fire Science and Engineering
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    • v.27 no.2
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    • pp.75-79
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    • 2013
  • The present study measured the light transmission to quantify the smoke density(smoke mass concentration) through the doorway in a compartment fire and performed the uncertainty analysis to evaluate the reliability of the measurement technique. The optical light extinction method based on Bourguer's law was applied to estimate the smoke density of doorway exhausting smoke flow in upper layer of a compartment for methane gas fires. The measurement uncertainty of the light extinction measurement was evaluated for the light transmittance, path length, and specific mass extinction coefficient and the expanded uncertainty was estimated about 20% with confidence level of 95%. The mean smoke density through the doorway for the methane fire was calculated for quasi-steady fire and the smoke density linearly increased as the GER increased.