• 지역사회간호학회지
• /
• 제21권1호
• /
• pp.128-138
• /
• 2010

Purpose: This study was to identify the relation between productive activity and physical and psychological ability in elders. Methods: A total of 294 subjects aged between 60 and 92 were selected through convenient sampling. Data were collected with a self-reported questionnaire from May to June, 2008. Collected data were analyzed by SPSS/PC Win. 15.0. Results: Of variance in productive activity, 13.3% was explained by house ownership, number of diseases, and successful aging. Of variance in physical and psychological ability, 25.4% was explained by house ownership, perceived health, number of diseases, and successful aging. The correlation coefficient between productive activity and physical and psychological ability was significant (r=.32, p<.001) Conclusion: Findings of this study may be useful in understanding the health status of community-dwelling elders and developing more specific health promotion programs.

• 지역사회간호학회지
• /
• 제32권1호
• /
• pp.86-94
• /
• 2021

Purpose: This descriptive study investigated the effects of self-efficacy and self-stigma on self-care in people with diabetes. Methods: The study included a total of 377 patients with diabetes enrolled in university hospitals in D city and public health centers in S city. Data were collected from 1 July to 31 August, 2017, and were analyzed using descriptive statistics, t-test, analysis of variance, Pearson's correlation coefficient, and hierarchical multiple regression. Results: Diabetes self-care was positively correlated with diabetes self-efficacy, whereas it was negatively correlated with diabetes self-stigma. Participants' education level, marital status, perceived health status, type of medication, self-efficacy, and self-stigma explained 42.4% of the variance in diabetes self-care. Conclusion: The findings indicate that diabetes self-efficacy and self-stigma are important factors for improving self-care in patients with diabetes. Therefore, systematic programs for enhancing self-efficacy and reducing self-stigma of these individuals should be developed.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 심포지엄 논문집 정보 및 제어부문
• /
• pp.105-107
• /
• 2004

In this work, we suggested the method which improves the efficiency of the face detection algorithm using Pulse-Coupled Neural Network. Face detection algorithm which uses the color information is independent on size, angle, and obstruction of a face. But the use of color information encounters some problems arising from skin-tone color in the background, intensity variation within faces, and presence of random noise, and so on. Depending on these conditions, we obtained the mean and variance of skin-tone colors by experiments. Then we introduce a preprocess that the pixel with a mean value of skin-tone colors has highest level value(255) and the other pixels in the skin-tone region have values between 0 and 255 according to a normal distribution with a variance. This preprocess leads to an easy decision of the linking parameters.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제22권6호
• /
• pp.57-65
• /
• 2017

Six soil subsampling methods were evaluated with explosive compounds-contaminated soils to quantify the variance associated with each method. The methods include modified grab sampling, simplified ripple splitting, fractional shoveling, coning & quatering, degenerate fractional shoveling, and rolling & quatering. All the methods resulted in significantly lower CV (coefficient of variation) of 1~5%, compared to common grab sampling that gave 8~98% of CV, possibly due to the reduction of grouping and segregation errors described by Gy sampling theory. Among the methods, simplified ripple splitting tends to result in lower explosive compounds concentrations, while the rolling & quatering gave the opposite result. Fractional shoveling method showed the least variance and the highest reproducibility in the analysis.

• 응용통계연구
• /
• 제19권2호
• /
• pp.283-290
• /
• 2006

일반적으로 Box-Cox변환과 같은 류의 멱변환은 분산 안정화 혹은 분포의 대칭성 향상 등을 목적으로 사용된다. 그러나 원 자료의 평균의 크기가 크면서 분산이 상대 적으로 작은 경우, 즉 변동계수가 작은 경우에는 제대로 작동하지 않는 것이 알려져 있다. 본 논문에서는 이러한 문제점을 해결하기 위한 이동-멱변환을 제안하고 모의실험과 실제 자료 분석을 통하여 그 효과를 확인하였다.

• 전자공학회논문지S
• /
• 제35S권7호
• /
• pp.46-52
• /
• 1998

This paper presents an experimenal proof for criteria of selecting an optimum adaptive beamforming (ABF) algorithm for a large distorted phased array. A single point target embedded in clutter model is suggested to compare four well-known ABF algorithms. These algorithms are tested to low variance and high variance real data for self-calibrating a large distored phased array. It is shown that these algorithms require at least one dominant scatterer with large radar cross section (RCS) or multiple scatterers with moderate RCS in the field of view. Experimental results are provided to demonstrate the comparisons of the four algorithems in terms of gain loss and image correlaion coefficient, along with corresponding reconstructed cross-range images and range-azimuth images.

• Journal of the Korean Data and Information Science Society
• /
• 제15권4호
• /
• pp.783-791
• /
• 2004

In this paper we review recent developments in nonlinear time series modeling on both conditional mean and conditional variance. Traditional linear model in conditional mean is referred to as ARMA(autoregressive moving average) process investigated by Box and Jenkins(1976). Nonlinear mean models such as threshold, exponential and random coefficient models are reviewed and their characteristics are explained. In terms of conditional variances, ARCH(autoregressive conditional heteroscedasticity) class is considered as typical linear models. As nonlinear variants of ARCH, diverse nonlinear models appearing in recent literature including threshold ARCH, beta-ARCH and Box-Cox ARCH models are remarked. Also, a class of unified nonlinear models are considered and parameter estimation for that class is briefly discussed.

• Journal of the Korean Data and Information Science Society
• /
• 제22권4호
• /
• pp.803-809
• /
• 2011

Properties of multivariate Shewhart and CUSUM charts for monitoring variance-covariance matrix, specially focused on correlation coefficient components, are investigated. The performances of the proposed charts based on control statistic Lawley-Hotelling $V_i$ and likelihood ratio test (LRT) statistic $TV_i$ are evaluated in terms of average run length (ARL). For monitoring correlation coe cient components of dispersion matrix, we found that CUSUM chart based on $TV_i$ gives relatively better performances and is more preferable, and the charts based on $V_i$ perform badly and are not recommended.

• 대한전자공학회논문지SP
• /
• 제39권4호
• /
• pp.470-476
• /
• 2002

본 논문에서는 순환 DFT 기반의 위상 측정 알고리즘을 구현함에 있어서 계수 근사 및 주파수 변이에 따른 성능 열화를 해석하였다. 오차의 영향을 해석하기 위해서 근사 순환 DFT식을 이용하여 오차 방정식(error dynamics)을 정의하고 이의 통계적 특성을 이용하여 오차의 특성을 분석한다. 오차 전력은 오차파급의 주요 영향 요소인 근사 bit수, DFT 구간 길이와 잡음에 관한 closed-form으로 유도되어 진다. 해석적으로 유도한 식과 시뮬레이션 실험을 통해 얻을 결과를 비교하여 타당성을 확인하였다.

• The Journal of Asian Finance, Economics and Business
• /
• 제7권9호
• /
• pp.95-104
• /
• 2020

In financial economics studies, the autoregressive model has been a workhorse for a long time. However, the model has a fixed value on every parameter and requires the stationarity assumptions. Time-varying coefficient autoregressive model that we use in this paper offers some desirable benefits over the traditional model such as the parameters are allowed to be varied over-time and can be applies to non-stationary financial data. This paper provides the Monte Carlo simulation studies which show that the model can capture the dynamic movement of parameters very well, even though, there are some sudden changes or jumps. For the daily data from January 1, 2015 to February 12, 2020, our paper provides the empirical studies that Thailand, Taiwan and Tokyo Stock market Index can be explained very well by the time-varying coefficient autoregressive model with lag order one while South Korea's stock index can be explained by the model with lag order three. We show that the model can unveil the non-linear shape of the estimated mean. We employ GJR-GARCH in the condition variance equation and found the evidences that the negative shocks have more impact on market's volatility than the positive shock in the case of South Korea and Tokyo.