• 한국디지털건축인테리어학회논문집
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• 제12권1호
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• pp.71-79
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• 2012

This study aims at finding relationships between the competitiveness of cities and the size or distance of them, based on some premises; (1) the competitiveness can be measured on the interval-ratio level, that is, factor scores, (2) a hypothesis that the spatial interaction model is valid for the relationships can be generally accepted. Based on the general recognition a research hypothesis that the more is the population or the nearer is the distance from a central city the higher is the competitiveness score is constructed. According to the premises 5-factor scores and composite score are calculated by means of regression method, and the scores are regressed on cities' populations and distances from Seoul city. Using bootstrapping method for the tests of significance is effective due to small sample of 21 cities. Results of the analyses show that most aspects of the hypothesis should be rejected or adjusted. Scores on Health-welfare factor, public service factor, and commercial vitality factor have no relation to the cities' sizes or distances. But the results also find the facts that the strong (negative) relationships exist between (1) educational base factor score and population, (2) density factor score and distance. Although this study improves systematic and analytic understanding of spatial interaction patterns, the understanding should be invalid for the general context because it has used the data on 21 cities in the capital region at the time of 2009.

• 한국측량학회지
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• 제17권2호
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• pp.129-136
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• 1999

영상분류 결과는 지형적 영향, 영상의 상태 등에 따라 전체 영상에 대하여 균일하지 않을 수 있다. 본 연구에서는 분류 결과의 불균일성과 위성영상 분류 오차의 공간적 분포를 평가하기 위해 ISDd (Index of Spatial Distribution by distance) 와 ISDs (ISD by scatteredness)의 개념을 제안하였다. ISDd는 지표화된 오분류 화소간의 거리이고, ISDs는 오분류 화소의 산포도에 관한 통계적 지표이다. 실제 위성영상에 대한 실험을 통하여 ISDd와 ISDs를 계산 및 평가하였으며, 실제 국지적 오분류 영역을 추출하여 오분류의 원인을 고찰하였다. 본 연구 결과, ISDd와 ISDs를 동시에 사용하여 오분류 화소의 국지적 밀집 여부와 밀집 정도의 평가가 가능하였으며, 그 결과를 토대로 영상의 일부분에 대한 분류결과의 채택/기각을 결정할 수 있었다. 따라서, 전체 분류정확도 외에 공간분포지표를 사용함으로써 사용자는 오분류 화소의 공간적 분포 상태를 파악할 수 있으며, 분류 결과의 적합성 및 신뢰성 판단을 위한 추가적인 기준을 가질 수 있다.

• 보건행정학회지
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• 제26권3호
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• pp.233-241
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• 2016

Background: This study purposed to analyze and understand how spatial accessibility of patients influenced the number of outpatient visits for the internal medicine of a hospital. Methods: A hospital with 100 beds in Seoul, South Korea provided data from 2013 January 1 to 2013 June 30. Euclidean distance and road ares were used to represent the spatial accessibility. Patient level data and dong level data were collected and used in spatial analysis. Dong level data was converted into grid level ($500{\times}500m$) for the multivariate analysis. Hot-spot analysis and generalized linear model were applied to the data collected. Results: Hot-spots of outpatient visits were found around the study hospital, and cold-spots were not found. Number of outpatient visits was varied by the distance between patient resident and hospitals, and about 80% of total outpatient visits was occurred in within the 5 km from study hospital, and 50% was occurred in within 1.6 km. Spatial accessibility had significant influences on the outpatient visits. Conclusion: Findings provide evidences that spatial accessibility had influences on the patients' behaviors in utilizing the outpatient care of internal medicine in a hospital. Results can provide useful information to health policy makers as well as hospital managers for their decision making.

• Journal of Ecology and Environment
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• 제30권2호
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• pp.201-207
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• 2007

Researchers have used a variety of methods to measure patterns of animal movement, including the use of spatial data (mapping the position of a moving animal at specified intervals) and direct estimation of travel path length by pacing under a moving animal or group. I collected movement data from five groups of siamangs (Symphalangus syndactylus) using two different methods concurrently to estimate the effects of the method of data collection on estimates of daily path length (DPL). Estimates of DPL produced from spatial data collected at 15-minute intervals were 12% lower than estimates of DPL produced by pacing under the traveling animal. The actual magnitude of the difference was correlated with the travel distance, but there was no correlation between the proportional difference and the travel distance. While the collection of spatial data is generally preferable, as spatial data permit additional analyses of patterns of movements in two or three dimensions, the relatively small difference between the DPL's produced using different methods suggests that pacing is an acceptable substitute where the collection of spatial data is impractical. I also subsampled the spatial data at increasing time intervals to assess the effect of sampling interval on the calculation of daily path lengths. Longer sampling intervals produced significantly shorter estimates of travel paths than shorter sampling intervals. These results suggest that spatial data should be collected at short time intervals wherever possible, and that sampling intervals should not exceed 30 minutes. Researchers should be cautious when comparing data generated using different methods.

• 한국농공학회논문집
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• 제54권3호
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• pp.55-63
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• 2012

Soil properties are not random values which is represented by mean and standard deviation but show spatial correlation. Especially, soils are highly variable in their properties and rarely homogeneous. Thus, the accuracy and reliability of probabilistic analysis results is decreased when using only one random variable as design parameter. In this paper, to consider spatial variability of soil property, one-dimensional random fields of coefficient of consolidation ($C_v$) were generated based on a Karhunen-Loeve expansion. A Latin hypercube Monte Calro simulation coupled with finite difference method for Terzaghi's one dimensional consolidation theory was then used to probabilistic analysis. The results show that the failure probability is smaller when consider spatial variability of $C_v$ than not considered and the failure probability increased when the autocorrelation distance increased. Thus, the uncertainty of soil can be overestimated when spatial variability of soil property is not considered, and therefore, to perform a more accurate probabilistic analysis, spatial variability of soil property needed to be considered.

• 농촌계획
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• 제26권3호
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• pp.103-113
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• 2020

Land price can be affected by convenience or psychological repulsion like PIMFY (Please In My Front Yard) or NIMBY (Not In My Back Yard) for various facilities. The purpose of this study is to evaluate whether non-preferred facilities are related to NIMBY impact that negatively affect land prices using the spatial econometrics models which are spatial autoregressive models (SAR), spatial errors models (SEM), and general spatial model (SAC). The land price in urban area increases by 0.07-0.2% when the distance from aversion facilities increases by 1%. However, the land price in rural areas decreases when the distance from aversion or pollution facilities increase. Therefore, these facilities in rural areas located in the areas with higher land price because funeral homes located in center of rural administrative areas and charnel house or crematorium located in the fringe of urban areas. That is, this study explain the difference between land price and non-preferred facilities in urban and rural areas and why there are more N IMBY symptoms in urban areas.

• 한국정보과학회논문지:데이타베이스
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• 제29권1호
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• pp.72-78
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• 2002

거리조인은 R-트리를 사용하여 두 공간 데이터 집합 사이의 데이터쌍을 거리 상 가까운 순으로 검색하는 공간조인이다. 거리조인은 R-트리를 하향식으로 순회하면서 생성되는 노드쌍들을 거리값 순으로 우선순위 큐에 저장한다. 본 논문에서는 거리조인 처리시 우선순위 큐 안에서 동점자 노드쌍들의 우선 순위 정책이 알고리즘의 성능을 많이 좌우할 수 있음을 보여주고, 이를 위한 최적화된 2차 우선 순위 기법을 제안한다. 실험을 통하여, 제안한 기법이 다른 기법에 비하여 항상 좋은 성능을 나타냄을 보여준다.

• International Journal of Internet, Broadcasting and Communication
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• 제9권1호
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• pp.72-80
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• 2017

In this work, an efficient transmit antenna selection approach for the quadrature spatial modulation (QSM) systems is proposed. The conventional Euclidean distance antenna selection (EDAS)-based schemes in QSM have too high computational complexity for practical use. The proposed antenna selection algorithm is based on approximation of the EDAS decision metric employed for QSM. The elimination of imaginary parts in the decision metric enables decoupling of the approximated decision metric, which enormously reduces the complexity. The proposed method is also evaluated via simulations in terms of symbol error rate (SER) performance and compared with the conventional EDAS methods in QSM systems.

• 방사선산업학회지
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• 제11권3호
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• pp.167-171
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• 2017

This study examined the effectiveness degree of a protective apron that is taken not to be exposed to the first ray or scattered rays, for X-ray of thick subject like lateral lumbar, and the results are as follows; First, spatial dose by scattered rays is shielded by 3 mmPb protective apron, 86.8% at a distance of 50 cm, 92.7% at 100 cm, and 95.6% at 200 cm, when minimizing the field size, while 89% at a distance of 50 cm, 92.3% at 100 cm, and 95.2% at 200 cm, when maximizing the field size. Second, 1st exposure dose is shielded by 3 mmPb protective apron, 93.7% at a distance of 50 cm, 94.4% at 100 cm, and 93.6% at 200 cm, when minimizing the field size, while 93.7% at a distance of 50 cm, 93.6% at 100 cm, and 94.2% at 200 cm, when maximizing the field size.

• 대한수학교육학회지:학교수학
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• 제19권4호
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• pp.663-690
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• 2017

본 연구는 초등학교 수학에서 공간 감각 중 공간 방향 요인과 요소를 살펴보고, 이를 바탕으로 우리나라, 싱가포르, 일본, 중국, 홍콩, 핀란드, 독일, 미국의 교육과정과 교과서에서 다루고 있는 공간 방향과 관련된 내용을 비교 분석함으로써 앞으로 우리나라 초등학교 수학에서 공간 방향 지도를 위한 시사점을 제공하는 데 목적이 있다. 이를 위해 이론적 고찰을 통해 공간 방향 요인과 요소를 알아보고, 이를 기초로 지도 학년과 학년별 내용, 위치, 방향, 좌표, 경로, 거리의 공간 방향 요소와 요소별 내용과 현실 맥락을 중심으로 국가별 교육과정과 교과서를 분석하였다. 이론적 고찰과 교과서 비교 분석 결과 공간 방향 지도를 위한 시사점으로 교육과정에 공간 방향 내용과 기간 확장 및 고학년의 공간 방향 지도 강화, 공간 방향 내용 요소에 대한 기본적인 경험 제공, 학생들 주변의 친숙하고 현실적인 맥락 활용을 제안하였다.