• Communications for Statistical Applications and Methods
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• v.16 no.2
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• pp.325-334
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• 2009

In this research, we propose a nonparametric test procedure for the right censored and grouped data under the additive hazards model. For deriving the test statistics, we use the likelihood principle. Then we illustrate proposed test with an example and compare the performance with other procedure by obtaining empirical powers. Finally we discuss some interesting features concerning the proposed test.

• International Journal of Reliability and Applications
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• v.8 no.2
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• pp.199-210
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• 2007

This paper presents estimations of the generalized Rayleigh distribution model based on grouped and censored data. The maximum likelihood method is used to derive point and asymptotic confidence estimates of the unknown parameters. The results obtained in this paper generalize some of those available in the literature. Finally, we test whether the current model fits a set of real data better than other models.

• Journal of Korean Academy of Nursing
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• v.26 no.1
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• pp.5-14
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• 1996

The purpose of this study is to find the Korean women's view to pregnancy within the Korean cultural context, to help nurses understand psychosocioemotional schema of the pregnant women, and to contribute to theory-building on the meaning of pregnancy. The interviewees were 21 women in their twenties or thirties and they were selected by theoretical sampling technique. Thirteen women of the interviewees were single and others married. Data were collected by in-depth interviews from September November in 1994. Interviews were tape-recorded and transcribed. Data were analyzed by Van Kaam's phenomenological method. Results were as follows. Eighty two descriptive expression were found and they were grouped under fourteen common factors. These are 「to maintain family」, 「instinct」, 「obligation」, 「what one should do」, 「to make home」, 「to tie couple firmly」, 「means to overcome a period of lassitude」, 「token of love」, 「hope」, 「to avoid loneliness」, 「wanted to have a baby」, 「to provide for old ages」, 「to be a mother」, 「to achieve her desire through baby」. Finally, fourteen common factors were grouped under four higher categories. Five common factors, 「to maintain family」, 「instinct」, 「obligation」, 「what one should do」, 「to make home」 were grouped under〈custom〉. Three factors, 「to tie couple firmly」, 「means to overcome a period of lassitude」, 「token of love」 were grouped under 〈love between couple〉. Four factors, 「hope」, 「to avoid loneliness」, 「wanted to have a baby」, 「to provide for old ages」 were grouped under 〈pursuiting safety〉. Two factors, 「to be a mother」, 「to achieve her desire through baby」 were grouped under 〈self-fulfillment〉. At present, the most distinguishing motivation of childbearing was rooted in the cultural custom. Korean women thought that it was their duties to have children and children were necessary in life. But they were beginning to recognize that baby could tie couple more firmly and get rid of their loneliness. Korean women no longer considered their children as the one who would take care of them when they were old or who would satisfy their unmet needs. As pregnancy is not women's duty only, authors recommend further studies on men's view to pregnancy.

• Child Health Nursing Research
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• v.28 no.4
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• pp.280-290
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• 2022

Purpose: This study aimed to explore nursing students' experiences of neonatal nursing simulations using peer tutoring. Methods: In this qualitative content analysis study, data were collected using a narrative survey and focus group interviews with 27 third-year nursing students and six fourth-year nursing students from April to May 2022. Content analysis of the collected data was conducted. Results: Four categories-"stabilizing emotionally through each other", "advancing together", "difficulties in relationships", and "hoping to continue"-and nine sub-categories were extracted. The sub-categories "reduced burden" and "gaining confidence" were grouped into the first category, "stabilizing emotionally through each other". The sub-categories "being motivated to learn," "increased learning ability", and "preparation as a process" were grouped under "advancing together", and "attitudes affecting study environment" and "depending on help" were grouped into the third category of "difficulties in relationships". The fourth category of "hoping to continue" had "wanting to supplement for development" and "wanting to participate in different roles" as sub-categories. Conclusion: Based on the results of this study, we expect pediatric nursing practicum education to improve through the active use of neonatal nursing simulation education incorporating peer tutoring.

• Journal of the Korean Statistical Society
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• v.30 no.1
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• pp.1-20
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• 2001

We present how bootstrap methods can be used to conduct inference on the rates of Poisson distributions when only the grouped data are available. A theoretical justification for the validity of bootstrap is given with an illustration of proposed method using a data set obtained fro ma pathology laboratory test. Traditional asymptotic methods are compared with bootstrap methods in computing the estimated standard errors and achieved significance levels for one sample and two sample tests. Bootstrap methods are shown to possess a nice property that he small sample distribution of the relevant statistics can be readily obtained from the bootstrap copies.

• The Transactions of the Korea Information Processing Society
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• v.7 no.12
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• pp.3821-3828
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• 2000

Many software projects collect grouped failure data (failures in some failure interval or in variable time interval) rather than individual failure times or failure count data during the testing or operational phase. This paper presents the neural network (NN) modeling that is dble to predict cumulative failures in the variable future time for grouped failure data. ANN's predictive ability can be affected by what it learns and in its ledming sequence. Eleven training regimes that represents the input-output of NN are considered. The best training regimes dre selected rJdsed on the next' step dvemge reldtive prediction error (AE) and normalized AE (NAE). The suggested NN models are compared with other well-known KN models and statistical software reliability growth models (SHGlvls) in order to evaluate performance, Experimental results show that the NN model with variable time interval information is necessary in order to predict cumulative failures in the variable future time interval.

• Journal of Korean Society for Quality Management
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• v.32 no.4
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• pp.208-219
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• 2004

This paper considers a nonparametric estimation of lifetime distribution for ramp stress tests with stress bound under intermittent inspection. The test items are inspected only at specified time points an⊂1 so the collected observations are grouped data. Under the cumulative exposure model, two nonparametric estimation methods of estimating the lifetime distribution at use condition stress are proposed for the situation which the time transformation function relating stress to lifetime is a type of the inverse power law. Each of items is initially put on test under ramp stress and then survivors are put on test under constant stress, where all failures in the Inspection interval are assumed to occur at the midi)oint or the endpoint of that interval. Two proposed estimators of quantile from grouped data consisting of the number of items failed in each inspection interval are numerically compared with the maximum likelihood estimator(MLE) based on Weibull distribution.

• The Korean Journal of Applied Statistics
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• v.30 no.1
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• pp.135-145
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• 2017

Principal component analysis (PCA) describes the variation of multivariate data in terms of a set of uncorrelated variables. Since each principal component is a linear combination of all variables and the loadings are typically non-zero, it is difficult to interpret the derived principal components. Sparse principal component analysis (SPCA) is a specialized technique using the elastic net penalty function to produce sparse loadings in principal component analysis. When data are structured by groups of variables, it is desirable to select variables in a grouped manner. In this paper, we propose a new PCA method to improve variable selection performance when variables are grouped, which not only selects important groups but also removes unimportant variables within identified groups. To incorporate group information into model fitting, we consider a hierarchical lasso penalty instead of the elastic net penalty in SPCA. Real data analyses demonstrate the performance and usefulness of the proposed method.

• Corrosion Science and Technology
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• v.20 no.2
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• pp.94-104
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• 2021

Atmospheric corrosion severity associated with aircraft parking environment was studied using metallic specimens, and temperature and humidity sensors installed at each aircraft operating base. Data were analyzed after a year of exposure. Silver was used to measure chloride deposition by integrating X-ray photoelectron spectroscopy depth profiles. Carbon steel was utilized to determine the corrosion rate by measuring the weight loss. The time of wetness was determined using temperature and humidity sensor data. Analysis of variance followed by Tukey's "honestly significant difference" test indicated that atmospheric environment inside the shelter varied significantly from that of unsheltered parking environment. The corrosion rate of unsheltered area also varies with the roof. Hierarchical clustering analysis of the measured data was used to classify air bases into groups with similar atmospheric corrosion. Bases where aircraft park at a shelter can be grouped together regardless of geographical location. Unsheltered bases located inland can also be grouped together with sheltered bases as long as the aircraft are parked under the roof. Environmental severity index was estimated using collected data and validated using the measured corrosion rate.

• Journal of the Korean Society of Costume
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• v.55 no.3 s.93
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• pp.33-46
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• 2005

The purpose of this study is to examine the mediate effect of gender on the differences of consumers grouped by the level of fashion interest. Data was collected from 280 men and women of their twentieth and analyzed using crosstab analysis, ANOVA, scheff'e test, x$^{2}$ test, and regression. The results are as follows. First, high interest groups showed little difference in the clothing shopping orientation and showed significant differences in the clothing purchasing behaviors(visiting store, time spent for shopping, and monthly clothing expenditure) between men and women. Second, low interest groups showed a lot of differences in both the clothing shopping orientation and the clothing purchasing behaviors between men and women. Third, several dimensions of clothing shopping orientation were more influenced from fashion interest level rather than the gender of consumers, and other several dimensions, visiting store, and the time spent for shopping were more influenced from gender rather than fashion interest level. These results imply that the gender of consumer has mediate effect on the behaviors of consumers grouped by the level of fashion interest, and the consumers of same fashion interest level must be approached concerning the gender of consumers.