• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.3
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• pp.9-18
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• 2001

In this paper, we present the joint symbol detection and channel estimation for an orthogonal frequency division multiplexing (OFDM) system in fading channels. The proposed methods are based on decision-directed channel estimation (DDCE) method and their symbol detection is achieved by using Viterbi algorithm. This Viterbi decision-directed channel estimation (VDDCE) method tracks time-varying channels and detects a maximum likelihood symbol sequence. Recursive Viterbi decision-directed channel estimation (RVDDCE) method based on VDDCE method is proposed to shorten the detecting depth. In this method, channel estimate and Viterbi processing are recursively performed every interval of training symbol. Also, average chann'el estimation (ACE) technique to reduce the effect of additive white Gaussian noise (AWGN) is applied VDDCE method and RVDDCE method. These proposed methods arc demonstrated by computer simulation.

• The Korean Journal of Applied Statistics
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• v.21 no.2
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• pp.247-264
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• 2008

This paper considers the integrated process control procedure for detecting special causes in an ARIMA(0,1,1) process that is being adjusted automatically after each observation using a minimum mean squared error adjustment policy. It is assumed that a special cause can change the process mean and the process variance. We derive expressions for the process deviation from target for a variety of different process parameter changes, and introduce a control chart, based on the generalized likelihood ratio, for detecting special causes. We also propose the integrated process control scheme bases on the future loss. The future loss denotes the cost that will be incurred in a process remaining interval from a true out-of-control signal.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.9
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• pp.1231-1236
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• 2005

Genetic parameters for first lactation milk production based on test day (TD) records of 56319 Iranian Holstein cows from 655 herds that first calved between 1991 and 2001 were estimated with restricted maximum likelihood method under an Animal model. Traits analyzed were milk yield and milk fat percentage. Heritability for TD records were highest in second half of the lactation, ranging from 0.11 to 0.19 for milk yield and 0.038 to 0.094 for milk fat percentage respectively. Estimates for lactation records for these traits were 0.24 and 0.26 respectively. Genetic correlations between individual TD records were high for consecutive TD records (>0.9) and decreased as the interval between tests increased. Estimates of genetic correlations of TD yield with corresponding lactation yield were highest (0.78 to 0.86) for mid-lactation (TD3 to TD8). Phenotypic correlations were lower than corresponding genetic correlations, but both followed the same pattern. For milk fat percentage no clear pattern was found. Results of this study suggested that TD yields especially in mid-lactation may be used for genetic evaluation instead of 305-day yield.

• Korean Journal of Child Studies
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• v.32 no.5
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• pp.49-65
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• 2011

The purpose of this study was to investigate the structural relationship between the related variables of children's internalization and externalization of problems. A total of 709 elementary school students residing in Daegu City and Kyungpook province completed questionnaires which assessed family interaction functions, emotional regulation, self-control, and internalization and externalization of problems. The sample variance-covariance matrix was analyzed using AMOS 19.0, and a maximum likelihood minimization function. Goodness of fit was evaluated using the SRMS, RMSEA, and its 90% confidence interval, CFI, and TLI. The results were as follows : First, the function of family interaction, and emotional regulation had a significant direct effect on the internalization of problems. Moreover, emotional regulation, self-control and internalization of problems had a statistically substantial direct effect on the externalization of problems. Second, family interaction functions did not have a statistically significant direct on children's externalization of problems, although it may well have an indirect effect on children's externalization of problems through emotional regulation and self-control. Finally, self-control did not enjoy a direct effect on children's internalization of problems.

• Journal of Families and Better Life
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• v.31 no.1
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• pp.99-111
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• 2013

The purpose of this study was to investigate the structural relationships among the related variables of peer relationship. 547 schoolage children's social support, self-esteem, empathy and peer relationship. Subjects of this study were 547 elementary school students residing in Daegu-Si completed questionnaires assessing peer relationship, social support, self-esteem, empathy. The sample variance-covariance matrix was analyzed using AMOS 20.0, and the maximum likelihood minimization function. The goodness of fit was evaluated using the SRMR, RMSEA and its 90% confidence interval, CFI, and TLI. The results were as follow. First, children's social support was found to hadn't direct effect on peer relationship. Second, children's self-esteem, empathy have a direct effect on peer relationship. Third, children's social support have a direct effect on self-esteem, empathy. and children's self-esteem have a direct effect on empathy.

• Child Health Nursing Research
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• v.26 no.1
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• pp.90-97
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• 2020

Purpose: The purpose of this study was to investigate the effects of a breastfeeding support program (BSP) on the prevalence of exclusive breastfeeding and growth in late-preterm infants. Methods: A quasi-experimental study was conducted. The participants were 40 late preterm infants (LPIs), of whom 20 were assigned to the experimental group and 20 to the control group. For the mothers in the experimental group, a BSP was provided prior to the LPIs' discharge and reinforced once a week for 4 weeks. Information on the feeding type was collected by observation and the LPIs' body weight was measured. Results: There were significant differences in feeding type by group and time. Exclusive breastfeeding was 5.18 times more common in the experimental group than in the control group (odds ratio=5.18, 95% confidence interval=1.11~16.70). However, weekly weight gain did not show a significant relationship with group and time (F=0.40, p=.712). Conclusion: The BSP was helpful for increasing the rate of exclusive breastfeeding in LPIs. Furthermore, the LPIs in the experimental group, which had a higher likelihood of being exclusively breastfed, showed an equivalent amount of weight gain as the LPIs in the control group, in which infants were more likely to be formula-fed.

• Journal of Information Technology Applications and Management
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• v.23 no.4
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• pp.117-125
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• 2016

Software reliability in the software development process is an important issue. In infinite failure non-homogeneous Poisson process software reliability models, the failure occurrence rates per fault. can be presented constant, monotonic increasing or monotonic decreasing pattern. In this paper, the reliability software cost model considering decreasing intensity function was studied in the software product testing process. The decreasing intensity function that can be widely used in the field of reliability using power law process, log-linear processes and Musal-Okumoto process were studied and the parameter estimation method was used for maximum likelihood estimation. In this paper, from the software model analysis, we was compared by applying a software failure interval failure data considering the decreasing intensity function The decreasing intensity function model is also efficient in terms of reliability in the arena of the conservative model can be used as an alternating model can be established. From this paper, the software developers have to consider life distribution by preceding information of the software to classify failure modes which can be gifted to support.

• Korean Journal of Childcare and Education
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• v.16 no.2
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• pp.141-160
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• 2020

Objective: The purpose of this study was to investigate structural relationships among variables related to pre-service childcare teachers' teaching efficacy. Methods: The participants in this study were 408 students in the department of child studies. The students completed questionnaires assessing pre-service childcare teachers' teaching efficacy, social support, self-esteem, and satisfaction level for childcare practicum. Statistical methods for the data analysis were the SPSS 19.0 and AMOS 20.0. And the Maximum likelihood estimation method was used to model fit. Goodness of fit was evaluated using the SRMR, RMSEA and its 90% confidence interval, CFI, and TLI. Results: First, pre-service childcare teachers' social support, self-esteem and satisfaction level for childcare practicum were found to affect their teaching efficacy directly. Also pre-service childcare teachers' social support was found to affect their self-esteem and satisfaction level for childcare practicum directly. Conclusion/Implications: This study is theoretically meaningful in that it shows that high social support, self-esteem, and satisfaction level for childcare practicum can be the main factors that can increase the effectiveness of pre-service childcare teachers' teaching efficacy.

• Journal of Families and Better Life
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• v.30 no.3
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• pp.45-57
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• 2012

The purpose of this study was to investigate the structural relationships among different variables related to well-being. 748 elementary school students residing in Gumi-City, Pohang-City and Ulsan-City in Korea completed questionnaires about well-being, ego-resilience, self-esteem, basic psychological needs and parent attachment perceived by children. A variance-covariance matrix of this sample was analyzed using AMOS 19.0, and the maximum likelihood minimization function. The goodness of fit was evaluated via SRMR, RMSEA with a 90% confidence interval, CFI, and TLI. The results were as follows: First, children's ego-resilience, self-esteem, basic psychological needs and parent attachment were all found to have a significant direct effect on children's well-being. Second, children's self-esteem, basic psychological needs and parent attachment had a direct effect on children's ego-resilience. Third, children's basic psychological needs and parent attachment had a direct effect on children's self-esteem. Fourth, parent attachment had a direct effect on children's basic psychological needs.

• Journal of Korean Society for Quality Management
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• v.9 no.1
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• pp.3-11
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• 1981

A stress-strength model is formulated for s of k systems consisting of identical components. We consider minimum variance unbiased (MVU) estimation of system reliability for data consisting of a random sample from the stress distribution and one from the strength distribution when the two distirubtions are Weibull with unknown scale parameters and same known shape parameter. The asymptotic distribution of MVU estimate of system reliability in the model is obtained by using the standard asymptotic properties of the maximum likelihood estimate of system reliability and establishing their equivalence. Uniformly most accurate unbiased confidence intervals are also obtained for system reliability. Empirical comparison of the two estimates for small samples is studies by Monte Carlo simulation.