• The Korean Journal of Applied Statistics
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• v.13 no.2
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• pp.265-274
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• 2000

Relationship between the daily mortality and total suspended particulate(TSP) for the period of 1996-1997 was examined in Seoul, Korea. Generalized additive model was adapted for the analysis to allow the seasonality and long-term time effect in the air pollution and the nonlinear relationships with weather variables such as air temperature and relative humidity. An increase of 100 Ji9/m') TSP corresponds to 0.8-5.2 percent increase of the daily mortality Unidirectional (prospective and retrospective) case-crossover design results in large bias of the estimates. Bidirectional method gives relatively unbiased estimates but the standard errors are larger Case-crossover design should be used with caution in the situation where the data have seasonal trends like air pollution study.

• The Korean Journal of Applied Statistics
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• v.14 no.2
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• pp.415-427
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• 2001

공간통계학에서는 다변량 공간자료에 대한 예측방법으로서 코크리깅 기법을 이용한다. 본 논문에서는 코크리깅을 위한 첫 번째 단계인 교차베리오그램의 추정에 대한 감도분석 대신에 일반통계학적 측면에서 주성분점수를 이용한 감도분석방법을 제안한다. 변수가 2개인 경우, 교차베리오그램에 대한 감조분석의 결과와 제안된 주성분점수를 이용한 감도분석의 결과를 비교해 본다. 모의실험을 통하여 제안한 방법의 타당을 검증하고, 실제 자료를 이용한 사례분석의 결과로써 재확인해 본다.

• The Korean Journal of Applied Statistics
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• v.29 no.2
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• pp.279-289
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• 2016

Bioequivalence trials based on higher order crossover designs have recently been conducted for highly variable drugs since the Ministry of Korea Food and Drug Safety (MFDS) added new regulations in 2013 to widen bioequivalence limits for highly variable drugs. However, a statistical discussion of higher order crossover designs have not been discussed yet. This research proposes the statistical inference of bioequivalence based on $3{\times}3$ crossover design and discusses it with the MFDS regulations. An illustrated example is also given.

• Journal of the Korean Data and Information Science Society
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• v.23 no.6
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• pp.1165-1172
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• 2012

The purpose of this paper is to investigate the reality of the occupational pension and suggest annuitization over a lifetime of the occupational pension for the purpose of securing income after retirement. A survey and the empirical analysis such as regression and crosstabulation analysis are employed. An research on a case study of an advanced countries is also conducted. The crosstabulation analysis shows that the post-retirement amenities of the self-employed person and the lower income bracket are serious. Individual retirement pension is suggested for the self-employed person and Riester Pension in Germany is recommended for the lower income bracket. The cases in Australia and the UK are useful for annuitization over a lifetime of the occupational pension.

• The Korean Journal of Applied Statistics
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• v.24 no.1
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• pp.161-167
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• 2011

The primary variables are often systematically related to other influences apart from drug effect. For instance, there may be relationships to covariates such as health conditions or prognostic factors. When a $2{\times}2$ crossover experiment for bioequivalence is designed, the statistical adjustment for the influence of covariates should be considered if some covariates influence the drug effect. Statistical inference for assessing average bioequivalence for a $2{\times}2$ crossover design with covariates is given and an illustrated example is presented with discussion.

• Child Health Nursing Research
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• v.12 no.1
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• pp.122-133
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• 2006

본 연구의 목적은 아동 성폭력 상황 자체와 성폭력 가해자에 대한 간호사의 태도가 상황 판단에 미치는 영향을 규명하는데 초점을 둔다. 503명의 병원 간호사와 526명의 보건교사를 대상으로 vignette 디자인 설문조사를 실시하였다. 아동성폭력 상황 vignettes은 7가지의 특성 (성폭력 행위, 성폭력 빈도, 피해자의 연령, 피해자의 저항, 가해자의 연령, 가해자와 피해자의 교차성별, 가해자와 피해자와의 관계)을 조합하여 구성하였다. 1/4 factorial design의 결과로서 64개의 vignettes 이 도출되었으며 이 중 16개 vignettes을 무작위로 추출하여 그 vignettes에 나타난 각 성폭력 상황들의 심각정도를 표시하도록 하였다. 성폭력 가해자에 대한 문항들은 1) 가해자가 아동 성폭력을 하는 이유 2) 전형적인 성폭력 가해자3) 아동성폭력 가해자의 처벌방법에 관한 간호사의 태도를 묻는 것이었다. 자료분석은 Logistic Regression을 실시하였다. 연구결과에서 간호사들은 아동 성폭력 상황의 심각도를 판단할 때 주로 성폭력 상황에 의해 영향을 받고 아동 성폭력 가해자에 대한 개인적 태도는 거의 영향을 미치지 않는 것으로 나타났으며, 아동 성폭력 상황 특성 중 피해자의 저항, 성폭력 행위, 성폭력 빈도, 가해자의 연령, 가해자와 피해자의 교차성별 순으로 아동 성폭력상황의 심각도에 영향을 미치는 것으로 나타났다. 결론적으로, 간호사들은 아동 성폭력 상황에 직면하여 사례를 판단할 때 아동 성폭력 문제에 대한 개인의 태도에 영향을 받기보다는 사례 그 자체에 근거를 두고 판단하는 경향을 나타낸다. 본 연구 결과는 법적, 전문가적 의미에서 아동성폭력 신고자로서의 의무와 사례중재에 개입된 의료인으로서의 역할 수행에 긍정적인 면을 시사한다.

• Journal of Energy Engineering
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• v.8 no.1
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• pp.101-109
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• 1999

전력계통의 정태안정도 해석에서 발전기의 특성을 정확히 모델링하는 것을 해석결과의 정확도에 매우 큰 영향을 미치게 된다. 본 논문은 발전기 무한모선 계통을 사용하여 발전기의 특성을 정확히 해석하고자 하는 경우에 발전기의 포화특성을 종래의 동일축 전류성분에 의한 포화특성뿐만 아니라 교차자화 효과에 의한 포화특성까지 고려하여 보다 정확한 해석이 가능하도록 하였다. 동일축 성분의 포화 특성과 교차자화 효과에 의한 포화특성을 고려하여 발전기를 해석하기 위한 기준 좌표계로 발전기의 d축이 q축 보다 위상이 90$^{\circ}$앞서는 좌표계를 사용 관계식을 재정립하여 정태안정도 해석에 사용하던 기존의 발전기모델과 일치하도록 하였다. 사례연구를 통해서 포화특성을 정확히 고려하여 발전기를 모델링하는 것이 해석결과의 정확도에 매우 큰 영향을 미치는 것을 보였고, 다양한 계통조건에 대한 정태안정도 해석을 통해서 계통조건의 변화에 따라 포화특성에 영향을 미치는 요소들의 변화를 파악하였다.

• Journal of Korean Society of Transportation
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• v.22 no.2 s.73
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• pp.43-54
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• 2004

This study analyzes characteristics and applicability of genetic algorithms and genetic operators to optimize highway alignments. Genetic algorithms, one of artificial intelligence techniques, are fast and efficient search algorithms for generating, evaluation and finding optimal highway alignment alternatives. The performance of genetic algorithms as an optimal search tool highly depends on genetic operators that are designed as a problem-specific. This study adopts low mutation operators(uniform mutation operator, straight mutation operator, non-uniform mutation operator whole non-uniform mutation operator) to explore whole search spaces, and four crossover operators(simple crossover operator, two-point crossover operator, arithmetic crossover operator, heuristic crossover operator) to exploit food characteristics of the best chromosome in previous generations. A case study and a sensitivity analysis have shown that the eight problem-specific operators developed for optimizing highway alignments enhance the search performance of genetic algorithms, and find good solutions(highway alignment alternatives). It has been also found that a mixed and well-combined use of mutation and crossover operators is very important to balance between pre-matured solutions when employing more crossover operators and more computation time when adopting more mutation operators.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.725-733
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• 2018

With urbanization projects involving trunk roads progressing, many simple interchanges, which separate passing traffic into the main traffic and access subtraffic, are being constructed to maximize the traffic capacity. Under the current Road Connection Rule, the access-prohibited section in an interchange is determined based on the access lane and limit distance in the complete interchange road, but separate criteria for the simple interchange are not defined. This may cause confusion in the Road Management Office's determination of the access-prohibited section in the simple interchange, or lead to the application of the criteria for the access-prohibited section in the complete interchange without considering the features of such interchange. This study conducted a comparative analysis of the domestic and overseas systems related to the installation of access section in trunk roads, such as general national roads. This paper presents a survey of the methods for applying the access-prohibited section in the interchange along with the actual cases and proposes improvement measures for a rational calculation of the access prohibited installation section in the simple interchange to minimize the downsides associated with the application of the extremely strict criteria. The proposed road connection rule improvement measures based on the consideration of the purpose of installing the simple interchange and on the consideration the features of the simple interchange are expected to prevent administration confusion by the field road management offices as well as the waste of unnecessary efforts and costs by petitioners so they can boost the service satisfaction for people and the administrative reliability.

• Journal of the Economic Geographical Society of Korea
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• v.18 no.4
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• pp.450-466
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• 2015

This study examines why families move to neighborhoods at different levels of income. By analyzing a survey dataset of homeowners who sold and bought a house in 1999 in Franklin County, Ohio, in USA on their mobility decisions, this study examined the factors associated with cross-income residential location decisions. I categorized both survey respondents and neighborhoods into low-, middle-, and high-income levels and ran multinomial logit analyses for each of the low-, middle-, and high-income family groups to examine why families moved to neighborhoods at different levels of income. The analysis suggests that middle-income families moved to high-income neighborhoods because of school reputation and moved to low-income neighborhoods because of investment purposes.