• Journal of the Korean Geographical Society
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• v.43 no.4
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• pp.511-525
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• 2008

Residential segregation is often considered to be one of the social problems that intensify urban inequality This study reviews three different frameworks about the causes of residential segregation and tests their validity in the real world. The review focuses on racial/ethnic residential segregation in U.S. cities since it has been blamed for persistent socio-economic gap among racial/ethnic groups. The three different segregation frameworks include 'spatial assimilation' that attributes segregation to low degree of assimilation and acculturation, 'place stratification' to discriminatory practices in the housing and mortgage markets such as steering, blockbusting, and redlining, and 'resurgent ethnicity' to racial/ethnic preference in residential choice, particularly in-group attraction. As an effort to test their validity, the paper examined residential pattern changes of the four major Asian nationality groups through 1990s and found that their residences got decentralized but re-cluster in some selected suburbs. This supports 'resurgent ethnicity' largely and 'spatial assimilation' only partly.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.483-488
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• 1997

원자력발전소 가압기 밀립배관은 원자로냉각재계통 압력을 제어하는 기능을 가진 가압기와 원자로냉각재계통을 연결하는 ASME 1등급 기기로서 건전성 확보가 필수적이다 그러나 현재 운전중인 국내ㆍ외 원전의 가압기 밀림배관은 설계시 열성층화(Thermal Stratification) 현상발생 뿐만 아니라 동 현상이 배관 건전성에 미치는 영향이 전혀 고려되지 않아 본 연구에서는 국내 운전중인 원전 가압기 밀림배관에서 발생하는 열성층화 정도를 확인하고. ASME 코드에 입각한 평가방법론을 정립 설계조건과 운전조건에 대한 평가를 수행하므로써 건전성에 미치는 영향을 평가하였다.

• The Korean Journal of Applied Statistics
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• v.36 no.4
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• pp.337-347
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• 2023

Sampling designs often use stratified sampling, where elements or clusters of the study population are divided into strata and an independent sample is chosen from each stratum. The stratification strategy consists of stratification and sample allocation, which are important issues that are repeatedly considered in survey sampling. Although a stratified multistage sample design is often used in practice, the literature tends to discuss simple sampling in terms of stratum effects or stratum efficiency. This study examines an existing stratum efficiency measure for two-stage sampling and further proposes additional stratum efficiency measures using the design effect model. The proposed measures are used to evaluate the stratification strategy of the sample design for high school students of the 4^th Korean National Environmental Health Survey (KoNEHS).

• Korean Journal of Social Welfare Studies
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• v.44 no.2
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• pp.465-497
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• 2013

This paper criticizes the ontological and epistemological dichotomy in social sciences including social welfare and probes into Critical Realism as an alternative paradigm. Many theories for social welfare have adhered to dichotomous ontological standpoint, 'agency' vs. 'social structure', and Eco-system approach have occupied dominant position to integrate this dichotomy. These theoretical standpoint have had great influence on social work practice. On the other hand, dichotomous epistemological standpoint which is constituted of different views of phenomena, 'positivism' and 'constructionism', have had great influence on social work research and practice. These dichotomous ontological and epistemological approach have a limit to reveal qualitative nature of the relationship between agency and social structure, to ponder the deeper reality, the mechanism of stratified reality, and the reality being independent of agency. Replacing these approaches, Critical Realism unfold the theoretical potential as an alternative paradigm for social welfare through the discussion on stratified realty(the empirical, the actual, and the real), intransitive/transitive dimension, double hermeneutics in these dimensions, and the conditions for conceptualization, duality of structure and practice, transformation model of agency and structure.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.2
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• pp.19-28
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• 2018

In this paper, we studied on the sampling of ocean meteorological data to analyze signature of naval ships. The newest ocean meteorological data, that was quality controled by the Korea Meteorological Administration(KMA), was collected. Outliers were removed from the data by setting the usable range of data. After that, the data size was reduced through the random sampling method, taking geopolitical significance and effective area of buoy, for probabilistic analysis. Moreover, the sample sizes were set at 100, 200, and 400 by considering the population size and a 95% confidence level. The final sample was obtained using the two-dimensional stratified sampling method based on highly correlated water temperature and air temperature. The sum of the squared errors and the confidence interval was calculated to compare the result of sampling. As a result, this study proposed reasonable sample size for infra­red signature analysis of naval ships.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.255-260
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• 2010

최근 건축물은 초고층화 대형화 지하심층화 되어가고 있다. 한편, 이러한 건축물은 화재시 기존의 건축물 보다 피난안전성의 문제가 대두된다. 이에 따라 국내외에서는 성능적 피난안전계획을 목적으로 PBD를 시행하고 있다. 하지만 국내의 경우 국외에 비하여 그 방법론이 부족하고, 건축물의 피난용량이 부족한 시점에 놓여있다. 이러한 배경을 통하여 본 연구는 재실자 피난행동분석 중 피난계산에 중요한 요인인 출구유동계수를 조사하고, 기존의 국내외 문헌과 비교를 실시하였다. 이에 따라 종합표준치 1.88인/ms를 도출하였으며, 또한 실태조사의 한계성을 파악하고, 이를 통한 조사기법에 대한 프로세스를 제안하였다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.67-73
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• 2009

최근 건축물은 초고층화 대형화 지하심층화 되어가고 있다. 이러한 건축물의 성능적인 피난안전성을 확보하기 위한 대책으로서 성능설계, 화재영향평가, 초고층 및 지하연계 방재관련 특별법 등 많은 제도가 시행되지만 구체적인 방법론이 미비한 실정이다. 따라서 본 연구는 성능적인 피난안전성을 확보하기 위하여 피난행동 중 수직적인 피난속도식을 제안하기 위하여 지하공간의 계단을 선정하여 관찰하였다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.1
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• pp.67-75
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• 2011

This paper presents a new test technique for evaluating performance of vehicle detectors with interval estimation, not the conventional point estimation, for presenting statistical confidence interval. The methodology is categorized into three parts; sampling plan, analysis on the characteristic of evaluation indices, and the expression of evaluation results. Even though many statistical sampling plans exist, stratified random sampling is regarded as the most appropriate one, considering the detector performance characteristics that varies with traffic, illumination, and meteorological conditions. No magic bullet exists for evaluation index for detector evaluation, hence the characteristics of evaluation indices were thoroughly analyzed and a reasonable process for choosing the best evaluation index is proposed. Finally, the methodology to express the result of detector evaluation for the entire evaluation period and individual analysis interval is represented, respectively. To overcome the existing drawbacks in point estimation, interval estimation by which statistical confidence interval can be represented is introduced for enhancing statistical reliability of traffic detector evaluation. This research can make vehicle detector scheme improve one step forward.

• Journal of Digital Convergence
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• v.11 no.9
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• pp.29-43
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• 2013

The dominant perspective on institutional change of the GRI is the environment-dependence. GRI's institutions are, however, prone to change due to the endogenous factors. Therefore, we need a dynamic alternative model to analyze the interaction between the exogenous and endogenous factors around the GRI's institutions. In this paper, authors examined the changes in GRI's funding system. The results were verified in the layering which is a one of the dynamic institutional change forms. Owing to the interaction between the exogenous and endogenous factors, institutional reform's layers of the institution funding expansion have been continuously accumulated in order to modify the Project-Based System(PBS). Eventually expansion layers of the institution funding have grown more quickly than the Project-Based System(PBS), as a result, GRI's funding system has been changing centered on the Block funding.

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.2
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• pp.161-169
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• 2016

Purpose : To quantify the inter-fractional variation in prostate displacement and their dosimetric effects for prostate cancer treatment. Materials and Methods : A total of 176 daily cone-beam CT (CBCT) sets acquired for 6 prostate cancer patients treated with volumetric-modulated arc therapy (VMAT) were retrospectively reviewed. For each patient, the planning CT (pCT) was registered to each daily CBCT by aligning the bony anatomy. The prostate, rectum, and bladder were delineated on daily CBCT, and the contours of these organs in the pCT were copied to the daily CBCT. The concordance of prostate displacement, deformation, and size variation between pCT and daily CBCT was evaluated using the Dice similarity coefficient (DSC). Results : The mean volume of prostate was 37.2 cm3 in the initial pCT, and the variation was around ${\pm}5%$ during the entire course of treatment for all patients. The mean DSC was 89.9%, ranging from 70% to 100% for prostate displacement. Although the volume change of bladder and rectum per treatment fraction did not show any correlation with the value of DSC (r=-0.084, p=0.268 and r=-0.162, p=0.032, respectively), a decrease in the DSC value was observed with increasing volume change of the bladder and rectum (r=-0.230,p=0.049 and r=-0.240,p=0.020, respectively). Conclusion : Consistency of the volume of the bladder and rectum cannot guarantee the accuracy of the treatment. Our results suggest that patient setup with the registration between the pCT and daily CBCT should be considered aligning soft tissue.