• 지역사회간호학회지
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• 제12권3호
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• pp.570-581
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• 2001

The purpose of this study was to analyze consumers' expectation. perception and satisfaction. The subjects in this study were 200 employees who were employed in a department store. They experienced nursing services from the primary care center at the department store. The results were as follows: 1. The rank of perceived significance of nursing services is tangibility, reliability, assurance, responsiveness. and empathy, respectively. 2. The rank of perceived service quality is empathy. responsiveness. assurance. reliability. and tangibility. 3. The rank of expectation and the rank of perception about nursing services are same. They are assurance, reliability, responsiveness, tangibility, and empathy respectively. 4. The regression analysis, which related the effect of perceived service quality to consumers satisfaction, had R2 value of 22.9%. From the above results, it can be concluded that the higher consumers' satisfaction can be explained by the greater perceived service quality.

• 응용통계연구
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• 제28권2호
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• pp.241-250
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• 2015

경시적 자료 연구의 중요한 주제 중의 하나는 시간이 지남에 따라 개인의 건강 상태가 어떻게 변하는지를 추적하는 확률이다. 질병의 상태를 시간의 흐름에 따라 추적하는 것은 장기간에 걸친 임상적 관찰 연구의 계획과 분석, 그리고 질병의 예방과 치료에 중요한 의미를 지닌다. 본 논문에서는 두 다른 시점에서 각 개인의 건강 상태에 대한 조건부 확률을 추정해내는 순위 추적 확률에 대하여 연구하였다. 순위 추적 확률과 순위 추적 확률비를 추정하기 위하여 선형 혼합 효과 모형을 고려하였다. 본 논문의 방법은 아동을 대상으로 심혈관계 질환의 위험요인을 연구하는 역학 자료에 적용되었다.

• Communications for Statistical Applications and Methods
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• 제3권3호
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• pp.283-290
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• 1996

The simulation study shows that the rank transform test has relatively superior power advantages over the parametric analysis of variance test in many cases for a $2^3$ factorial design, particularly with heavy-tailed distributions of the error terms. However the rank transform test should be cautiously used when all main effects and interactions related to a testing effect are possibly present at the same time.

• Journal of the Korean Statistical Society
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• 제26권3호
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• pp.333-354
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• 1997

Computational algorithms to calculate M-estimators and rank estimators of regression parameters from left-truncated and right-censored data are developed herein. In the case of M-estimators, new statistical methods are also introduced to incorporate leverage assements and concomitant scale estimation in the presence of left truncation and right censoring on the observed response. Furthermore, graphical methods to examine the residuals from these data are presented. Two real data sets are used for illustration.

• 한국콘텐츠학회논문지
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• 제11권12호
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• pp.145-151
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• 2011

본 연구에서는 한국 온라인 게임 콘텐츠 시장에 대해 장르적 구분에 의거한 경쟁 구조를 가정하고, 장르에 따라 분류된 하부시장 내에서 각각 다르게 나타나는 경쟁 유형을 분석하였다. 먼저 장르별 1, 2위 게임 콘텐츠들의 시장지배력을 분석하기 위하여, 장르 내에서의 플레이타임 점유율과 표준편차 통계량을 활용하여, 장르별 ANOVA분석 및 Cluster 분석을 수행하였다. ANOVA 분석 결과에 따르면, 장르별 1위 게임의 점유율에서 'FPS/레이싱 > RTS/스포츠 > 포커 > 고스톱 > RPG > 아케이드 > 보드'의 관계가 있었고, 1위와 2위 게임의 플레이타임 합계 점유율에서는, 'RTS > FPS/레이싱 > 스포츠 > RPG > 고스톱 > 포커 > 아케이드 > 보드'의 관계가 확인되었다. 그 밖에 Cluster 분석에서는 시장지배적 성향의 강한 정도와 그 변동성이 유사한 수준에 있는 장르들의 군집을 구분하여 제시하였다.

• Journal of Astronomy and Space Sciences
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• 제37권2호
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• pp.131-142
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• 2020

As the laws of physics are expressed in a manner that makes their invariance under coordinate transformations manifest, they should be written in terms of tensors. Furthermore, tensors make manifest the characteristics and behaviors of electromagnetic fields through inhomogeneous, anisotropic, and compressible media. Electromagnetic fields are expressed completely in tensor form, F^αβ, which implies both electric field ${\overrightarrow{E}}$ and magnetic field ${\overrightarrow{B}}$ rather than separately in the vector fields. This study presents the Mathematica platform that generates and transforms a second-rank antisymmetric field-strength tensor F^αβ and whiskbroom pattern in Minkowski space. The platforms enhance the capabilities of students and researchers in tensor analysis and improves comprehension of the elegant features of complete structure in physics.

• Communications for Statistical Applications and Methods
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• 제22권1호
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• pp.41-54
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• 2015

In this article, we propose nonconcave penalties on a reduced-rank regression model to select variables and estimate coefficients simultaneously. We apply HARD (hard thresholding) and SCAD (smoothly clipped absolute deviation) symmetric penalty functions with singularities at the origin, and bounded by a constant to reduce bias. In our simulation study and real data analysis, the new method is compared with an existing variable selection method using $L_1$ penalty that exhibits competitive performance in prediction and variable selection. Instead of using only one type of penalty function, we use two or three penalty functions simultaneously and take advantages of various types of penalty functions together to select relevant predictors and estimation to improve the overall performance of model fitting.

• 한국통신학회논문지
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• 제33권4C호
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• pp.336-341
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• 2008

본 논문에서는 신호의 반 파장 간격으로 안테나 소자를 배치한 빔형성 시스템에서 다이버시티 이득을 얻을 수 있는 빔형성 알고리즘을 제안한다. 제안된 알고리즘은 수신 신호 공간을 스팬(span)하는 고유 벡터들을 이용하여 빔형성 한다. 본 논문에서는 채널 추정을 위한 최적의 고유 공간 차수를 정하기 위한 기준도 제안한다. 제안된 알고리즘을 적용한 빔형성 시스템은 기존의 빔형성 시스템과는 달리 각 퍼짐이 증가함에 따라 다이버시티 이득을 얻어 그 성능이 개선된다. 본 논문은 제안된 알고리즘의 설명과 함께 다양한 컴퓨터 시뮬레이션을 통한 제안 알고리즘의 성능 분석을 제공한다.

• 대한수학회지
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• 제57권2호
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• pp.401-414
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• 2020

It is computationally expensive to compute principal components from scratch at every update or downdate when new data arrive and existing data are truncated from the data matrix frequently. To overcome this limitations, incremental principal component analysis is considered. Specifically, we present a sliding window based efficient incremental principal component computation from a covariance matrix which comprises of two procedures; simultaneous update and downdate of principal components, followed by the rank-one matrix update. Additionally we track the accurate decomposition error and the adaptive numerical rank. Experiments show that the proposed algorithm enables a faster execution speed and no-meaningful decomposition error differences compared to typical incremental principal component analysis algorithms, thereby maintaining a good approximation for the principal components.

• Communications for Statistical Applications and Methods
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• 제22권5호
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• pp.415-434
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• 2015

In this paper we overview the literature on common features analysis of economic time series. Starting from the seminal contributions by Engle and Kozicki (1993) and Vahid and Engle (1993), we present and discuss the various notions that have been proposed to detect and model common cyclical features in macroeconometrics. In particular, we analyze in details the link between common cyclical features and the reduced-rank regression model. We also illustrate similarities and differences between the common features methodology and other popular types of multivariate time series modelling. Finally, we discuss some recent developments in this area, such as the implications of common features for univariate time series models and the analysis of common autocorrelation in medium-large dimensional systems.