• Communications for Statistical Applications and Methods
• /
• 제26권5호
• /
• pp.519-526
• /
• 2019

Response dimension reduction in a sufficient dimension reduction (SDR) context has been widely ignored until Yoo and Cook (Computational Statistics and Data Analysis, 53, 334-343, 2008) founded theories for it and developed an estimation approach. Recent research in SDR shows that a semi-parametric approach can outperform conventional non-parametric SDR methods. Yoo (Statistics: A Journal of Theoretical and Applied Statistics, 52, 409-425, 2018) developed a semi-parametric approach for response reduction in Yoo and Cook (2008) context, and Yoo (Journal of the Korean Statistical Society, 2019) completes the semi-parametric approach by proposing an unstructured method. This paper theoretically discusses and provides insightful remarks on three versions of semi-parametric approaches that can be useful for statistical practitioners. It is also possible to avoid numerical instability by presenting the results for an orthogonal transformation of the response variables.

• 한국지리정보학회지
• /
• 제14권4호
• /
• pp.92-101
• /
• 2011

본 연구는 기존 구도심부 상업지역의 공동화로 인한 쇠퇴현상이 나타나고 있어 현 시점에서 진주시의 도시공간구조를 살펴보고자 하였다. 도시공간구조 분석의 범위는 구득자료의 한계와 연구의 목적을 감안하여 진주시의 동지역으로 한정하였다. 진주의 도시공간구조를 밝히기 위하여 다변량해석(Multivariate Analysis)을 사용하여 분석한 결과 7개의 지역(중심지, 공업지, 일반주거지 등)으로 유형화할 수 있었다. 진주시는 장래 낙후된 도시이미지의 쇄신, 서부경남의 중심도시로의 부활을 위해서는 앞서 지역별 현상을 감안하여 도심 노후지역의 전면적인 도심재개발, 재건축사업 및 재정비촉진사업 등이 필요할 것으로 보이며, 상평공단 이전 및 초장동 일원과 연계한 신도시 건설, 현재 계획 중인 혁신도시의 차질 없는 추진이 필요할 것으로 판단된다.

• 수산해양교육연구
• /
• 제29권3호
• /
• pp.785-798
• /
• 2017

This study was conducted to evaluated the surface(10 variables) and bottom(10 variables) water quality, and sediment(3 variables) in the cage fish farm off Baegyado in Gamak Bay using a multivariate analysis from January 2013 to November 2014. Generally, the environmental data did not show a certain tendency by months during two years investigated. The pairwise simple correlation matrices among variables were also shown. The first four principal components of the surface water in 2013 explain 93% of the total sample variance; the first principal component($z_1$) showed the freshwater inflow and/or precipitation, $z_2$, $z_3$ and $z_4$ related to freshwater inflow and/or precipitation, organic matters and eutrophy, respectively; the first four principal components of the bottom water in 2013 explain 93% of the total sample variance; the $z_1$, $z_2$ and $z_4$ related to freshwater inflow and/or precipitation, and $z_3$ water temperature. In 2014, at the surface water the first three principal components explain 87%; the $z_1$, $z_2$ and $z_3$ related to water temperature, eutrophy and freshwater inflow and/or precipitation, respectively; at the bottom water the first three principal components explain 93%; $z_1$, $z_2$ and $z_3$ related to water temperature, freshwater inflow and/or precipitation and eutrophy. Half of the principal components related to freshwater inflow and/or precipitation.

• Nuclear Engineering and Technology
• /
• 제31권2호
• /
• pp.192-201
• /
• 1999

This paper proposes an improved signal processing strategy for accurate feedwater flowrate estimation in nuclear power plants. It is generally known that ∼2% thermal power errors occur due to fouling Phenomena in feedwater flowmeters. In the strategy Proposed, the noises included in feedwater flowrate signal are classified into rapidly varying noises and gradually varying noises according to the characteristics in a frequency domain. The estimation precision is enhanced by introducing a low pass filter with the wavelet analysis against rapidly varying noises, and an autoassociative neural network which takes charge of the correction of only gradually varying noises. The modified multivariate stratification sampling using the concept of time stratification and MAXIMIN criteria is developed to overcome the shortcoming of a general random sampling. In addition the multi-stage robust training method is developed to increase the quality and reliability of training signals. Some validations using the simulated data from a micro-simulator were carried out. In the validation tests, the proposed methodology removed both rapidly varying noises and gradually varying noises respectively in each de-noising step, and 5.54% root mean square errors of initial noisy signals were decreased to 0.674% after de-noising. These results indicate that it is possible to estimate the reactor thermal power more elaborately by adopting this strategy.

• Clinical and Experimental Pediatrics
• /
• 제64권8호
• /
• pp.408-414
• /
• 2021

Background: Complementary food in infancy is necessary for human growth, neurodevelopment, and health. However, the role of allergen consumption in early infancy and its effects on the development of food allergy or tolerance remain unclear. Purpose: To investigate the influence of age at the time of complementary food introduction on the development of asthma and atopic dermatitis in Korean children aged 1-3 years. Methods: We combined data from the Korea National Health and Nutrition Examination Survey collected from 2010 to 2014 and analyzed 1619 children aged 1-3 years who were included in the survey. Multivariate regression analysis was used to identify associations among type of feeding, age at the time of complementary food introduction, and doctor-diagnosed atopic dermatitis and asthma. Results: Age at the time of complementary food introduction was not significantly associated with doctor-diagnosed atopic dermatitis and asthma in children aged 1-3 years. In the univariate analysis, children with asthma showed higher water and sodium intake levels than nonasthmatic children. However, this relationship was not significant in the multivariate regression analysis. Conclusion: The present study revealed no statistically significant relationship between age at the time of complementary food introduction and the risk of atopic dermatitis and asthma in young Korean children. A national prospective study is needed to clarify the influence of age at the time of complementary food introduction on the development of allergic diseases.

• 응용통계연구
• /
• 제32권1호
• /
• pp.83-97
• /
• 2019

사회가 발전함에 따라 이용자의 다양한 분석 요구에 대응하기 위해 개인 단위로 구성된 마이크로데이터 제공이 증가했다. 나아가 센서스, 행정자료와 같은 전수자료를 마이크로데이터 형태로 제공받아 연구하고자 하는 요구 역시 커지고 있다. 정책결정, 학술목적 등을 위한 마이크로데이터 분석은 가치 창출 측면에서 대단히 바람직하다. 하지만 자료 유용성이 확보된 마이크로데이터 제공은 개인정보가 노출될 가능성이라는 위험을 가질 수 밖에 없다. 이에, 자료의 유용성을 확보하면서 개인정보보호를 보장할 수 있는 여러 방법들이 고려되어 왔다. 이러한 방법 중 하나로 재현자료(synthetic data)를 생성해서 활용하는 방법이 연구되어 왔다. 본 논문은 재현자료 생성과 관련된 방법론 및 주의사항을 소개하여, 재현자료의 이해를 도모하고자 한다. 이를 위해 재현자료 작성에 필수적인 다중대체, 베이지안 예측 모형 및 베이지안 붓스트랩 등의 개념들을 먼저 설명하고, 완전 재현자료 및 부분 재현자료에 대해 살펴본다. 특히, 재현자료 작성을 심도 깊이 이해하기 위해 순차회귀 다중대체(sequential regression multivariate imputation)를 이용해 경시적(longitudinal) 자료를 재현자료로 작성하는 구체적 사례를 살펴본다.

• 한국의류학회지
• /
• 제21권7호
• /
• pp.1227-1235
• /
• 1997

The purpose of this study was to classify the somatotype based on the side view and to analyze the characteristics of each somatotype. In order to reduce the burden of stocks and increase clothing fitness, systematic information on typical body sizes and somatotypes is essential. The subjects were 206 unmarried women aged from 19-29. Data were collected through anthropometry and photometry and analyzed by factor analysis, cluster analysis and analysis of variance. As the result of factor analysis for the classification of somatotypes, 8 factors which explain 74.7% of variance were extracted from 35 photometric and 17 anthrometric data. Using factor scores cluster analysis was carried out and the subjects were classified into 4 cluster.Each cluster was classified as bending type, swayback, turning over type and straight type accordding to its position to the relativeplumb line and their side view contour.

• 대한화학회지
• /
• 제31권6호
• /
• pp.567-575
• /
• 1987

한국산 고대유리 시료 45종을 입수하여 그속에 함유된 19종의 원소(Ag, As, Br, Ce, Co, Cr, Eu, Fe, Hf, K, La, Lu, Na, Ru, Sb, Sc, Sm, Th, Zn)는 중성자방사화분석에 의하고, Pb는 원자흡수분광분석법에 의해 각각 정량하였다. 이들 20종 원소의 분석데이타를 사용하여 원소 상호간의 상관관계를 상관메트릭스법으로 검토하였다. 그리고 주성분분석법으로 각 시료의 농도분포를 평면에 나타내었으며, 측정된 제조년대 및 발굴위치가 같은 시료가 모이면 이들 시료를 SIMCA를 위한 참조시료로 삼았다. 이들 참조시료 및 시험시료를 SIMCA에 의해 분류하였더니 참조시료 전부와 시험시료중 3종이 주성분분석법에 의한 분류결과와 일치하였다.

• 방사성폐기물학회지
• /
• 제21권3호
• /
• pp.371-381
• /
• 2023

Evaluating the effectiveness of the radiation protection measures deployed at the Centralized Radioactive Waste Management Facility in Ghana is pivotal to guaranteeing the safety of personnel, public and the environment, thus the need for this study. Radiagem^TM 2000 was used in measuring the dose rate of the facility whilst the personal radiation exposure of the personnel from 2011 to 2022 was measured from the thermoluminescent dosimeter badges using Harshaw 6600 Plus Automated TLD Reader. The decay store containing scrap metals from dismantled disused sealed radioactive sources (DSRS), and low-level wastes measured the highest dose rate of 1.06 ± 0.92 µSv·h^-1. The range of the mean annual average personnel dose equivalent is 0.41-2.07 mSv. The annual effective doses are below the ICRP limit of 20 mSv. From the multivariate principal component analysis biplot, all the personal dose equivalent formed a cluster, and the cluster is mostly influenced by the radiological data from the outer wall surface of the facility where no DSRS are stored. The personal dose equivalents are not primarily due to the radiation exposures of staff during operations with DSRS at the facility but can be attributed to environmental radiation, thus the current radiation protection measures at the Facility can be deemed as effective.

• Communications for Statistical Applications and Methods
• /
• 제27권1호
• /
• pp.149-161
• /
• 2020

In this paper we extend the functional principal component analysis for real-valued random functions to the case of Hilbert-space-valued functional random objects. For this, we introduce an autocovariance operator acting on the space of real-valued functions. We establish an eigendecomposition of the autocovariance operator and a Karuhnen-Loève expansion. We propose the estimators of the eigenfunctions and the functional principal component scores, and investigate the rates of convergence of the estimators to their targets. We detail the implementation of the methodology for the cases of compositional vectors and density functions, and illustrate the method by analyzing time-varying population composition data. We also discuss an extension of the methodology to multivariate cases and develop the corresponding theory.