• Journal of Korean Institute of Industrial Engineers
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• v.33 no.4
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• pp.419-423
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• 2007

In this paper, we consider the M/G/1 queueing system with randomized control of T-policy. Whenever the busy period ends, the server is turned off and takes multiple vacations whose interval is fixed time T with probability p or stays on and waits for arriving customers with probability 1-p. We introduce the cost function and determine the optimal combination of (p, T) to minimize the average cost per unit time.

• Journal of the military operations research society of Korea
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• v.25 no.2
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• pp.144-157
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• 1999

In this paper, we consider a new preventive replacement policy for the system which deteriorates while it is in operation with an increasing failure rate. The system is subject to two types of failure. A type 1 failure is repairable while a type 2 failure is not repairable. In the new policy, a system is replaced at the age of $t_p$ or at the instant the$\textsc{k}^{th}$ type 1 failure occurs, whichever comes first. However, if a type 2 failure occurs before a preventive replacement is performed, a failure replacement should be made. We assume that a type 1 failure can be rectified with a minimal repair. We also assume that a replacement takes a non-negligible amount of time while a minimal repair takes a negligible amount of time. Under a cost structure which includes a preventive replacement cost, a failure replacement cost and a minimal repair cost, we develop a model to find the optimal ($\textsc{k},t_p$) policy which minimizes the expected cost per unit time in the long run while satisfying a system availability constraint.

• International Journal of Reliability and Applications
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• v.1 no.1
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• pp.27-38
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• 2000

In a recent paper Iskandar ＆ Sandoh (1999) studied an opportunity-based age replacement policy for a system which has a warranty period (0,S]. When the system fails at age x $\leq$ S a minimal repair is performed. If an opportunity occurs to the system at age x, S $\leq$ x $\leq$ T, we take the opportunity with probability p to preventively replace the system, while we conduct a corrective .replacement when its fails in (S,T). Finally, if its age reaches T, we perform a preventive replacement, Under this policy the design variable is T. For the case when opportunities occur according to a homogeneous Poisson process, the long-run average cost of this policy was formulated and studied analytically by Iskandar & Sandoh (1999). The same problem is here analysed by using a graphical technique based on scaled TTT-transforms. This technique gives, among other things, excellent possibilities for different types of sensitivity analysis. We also extend the discussion to the situation when we have to estimate T based on times to failure.

• Journal of Industrial Convergence
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• v.21 no.11
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• pp.125-134
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• 2023

This study attemped to examine the effects of health care nursing policy education on nursing students' political efficacy, political participation, and political interest. It attempted to guide the direction of policy education within nursing curriculum. The subjects consisted of 89 nursing students of G-university from March 8, 2023, to June 21, 2023, including 44 in the experimental group and 45 in the control group. The health care nursing policy class was developed using the ADDIE(Analysis, Design, Development, Implementation, Evaluation) model of instructional design. Data analysis used the SPSS 25.0 program through mean, standard deviation, and independent sample t-test. The experimental group that participated in this education showed statistically significant improvement in political efficacy(t=2.34, p<.05) and intrinsic political efficacy(t=2.75, p<.05), as well as passive political participation score(t=2.22, p<.05) compared to before the intervention. Based on the findings of this study, it is suggested that health care nursing policy education should be structured to enhance external political efficacy and promote active political participation in future nursing curriculum.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4467-4477
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• 2015

This study was a nonequivalent pretest-posttest quasi-experimental study. It was conducted to evaluate the effects of a nursing geriatric nursing education for nursing students' attitude, perception and dementia policy. Subjects were 172 persons, sophomore of nursing college in the city of K and city of J, and the education group was taken 56 houres of gerontological nursing education. Data were analyzed by mean, percentage, t-test and ${\chi}^2$ using SPSS Win 20.0. As the result, in the education group, the knowledge of dementia was higher on average 27.10, and there was a significant statistic differance(t=7.500, p<000). In the atitude of demencia, the average of education group was higher on 4.10, and the atitude about dementia in the education group was more positive and here was a significant statistic difference(t=1.423, p<000). In the understanding of dementia policy, there was more positively improvement However, there was no significant statistic difference (t=1.70, p=.090). Through this result, we could reccognize that gerontological nursing education was effective for nursing students to improve knowledge about dotards, change atitude positively. Therefore we tried this study for provide basic data to develop gerontological nursing education progress combining theory with practice.

• Journal of the Korean Statistical Society
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• v.26 no.1
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• pp.147-154
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• 1997

An infinite dam with a compound Poisson input having exponential jumps is considered. As an output policy, we adopt the $P_{\lambda}$$^{M}$ Policy. After assigning costs to the dam we obtain the long-rum average cost per unit time of operating the dam and find the optimal values of .lambda. and M which minimize the long-run average cost.t.

• Journal of Korean Society for Quality Management
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• v.18 no.2
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• pp.1-8
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• 1990

Replacement policies based on both the system age and the random repair cost are studied. The system is replaced when it reaches age T (Policy A), or when it fails for the first time after age T (Policy B). If the system fails before age T, the repair cost is estimated and repair is then undertaken if the estimated cost is less than a predetermined limit L ; otherwise, the system is replaced. After repair, the system is as good as new with probability (1-p) or is as good as old with probability P. The expected cost rate is obtained, its behavior is examined, and way of obtaining optimal T and L is explored.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.5
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• pp.35-42
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• 2011

This study is to check the applicability of SWAT-APEX (Soil and Water Assessment Tool-Agricultural Policy / Environmental eXtender) model as combined watershed and field models by applying the APEX to paddies in a watershed (465.1 $km^2$) including Yedang reservoir. Firstly, the SWAT were calibrated with 3 years (2000~2002) daily streamflow and monthly water quality (T-N and T-P) data, and validated for another 3 years (2003~2005) data. The average Nash-Sutcliffe model efficiency (ME) of streamflow during validation was 0.73, and the coefficient of determination ($R^2$) of T-N and T-P were 0.77 and 0.73 respectively. Next, running the SWAT-APEX model with the SWAT calibrated parameters for paddies, the $R^2$ of T-N and T-P were 0.80 and 0.76 respectively. The results showed that SWAT-APEX model was more correctly predicted for T-N and T-P loads than SWAT model. The difference results between watershed and field models was predicted to have substantial impact on NPS loads, especially on T-N and T-P loads. Therefore, to improve negative NPS load simulations should be considered the model characteristics as simulating mechanism to properly select the NPS model for agricultural watershed.

• Journal of Korean Clinical Nursing Research
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• v.21 no.1
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• pp.105-115
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• 2015

Purpose: This descriptive correlational study was intended to analyze the relationship among menopausal symptoms. competency of self-care agency and social support in middle-aged women. Methods: Participants in the study were 140 women who were 45-60 years of old. Data were collected using structured questionnaires and analyzed using descriptive statistics., t-test, ANOVA, $Scheff{\grave{e}}^{\prime}s$ test and Pearson correlation coefficients. Results: The frequency and discomfort of menopausal symptom were low, but the mean discomfort score were higher than frequency score. Middle-aged women with lower competency of self care experienced more frequent menopausal symptoms (t=-0.28, p=.001) and more discomfort (t=-0.24, p=.004). However, There was no significant difference in menopausal symptoms according to social support. Conclusion: Nursing interventions to enhance competency of self-care agency in middle-aged women are required in order to reduce the discomfort of menopausal symptoms.

• Korean Security Journal
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• no.37
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• pp.137-163
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• 2013

This research will incorporate cases from U.S public schools to analyze the factors which influences the security within the school and efficient security patterns to suggest an adequate suggestion to elevate domestic school security system. This study is divided into two following models: a serious criminal offense model, which considers crimes occurred on campus as subordinate variables, and a school violence model, which considers as subordinate variables after limiting an act of delinquency and an a group action that can harm the safety of students, although they are not included in the categories of crimes. First, from analyzing the factors which influences security within school, the explanation power of serious crime offense safety model and school violence safety model is measured 12% and 11.3%. In serious crime offense safety model, the safety education for students, among the safety programs provided by schools(t=2.548, p=0.011), parent participation to school management(t=10.694, p=0.000), Security activities on campus(t=3.643, p=0.000), and CPTED activity(t=6.467, p=0.000) are statistically significant, as affecting factors on the safety from serious crimes. Similarly in school violence model, the safety education for students, among the safety programs provided by schools(t=3.228, p=0.001), parent participation to school management(t=12.034, p=0.000), security activities on campus(t=2.663, p=0.000), and CPTED activity(t=3.928, p=0.000) are statistically significant, as affecting factors on the safety from school violence. Second, according to the analytic results on figuring out the optimal pattern to heighten the security activities, the serious offence model's explanatory power was 4.4% and school violence safety model rated 3.9%. With the serious offense safety model, the activity factors which showed statistically significant in influencing safety from serious offenses were cooperation with local police force (t=2112, p=0.035), school policy management (t=3.309, p=0.001), security patrolling activity (t=2.548, p=0.011). In the school violence model, security activities initiated by the school which showed statistically significant from serious offenses were cooperation with local police force (t=2.364, p=0.018) and policy management (t=4.142, p=0.000). In accordance with the result of this study, education for students rather than education for teachers is more positive in terms of the safety on campus, and parent participation, like education, is consistently needed for the safety on campus. In case of CPTED activity, reinforcing plans should be prepared by intactly accepting examples in the USA. In case of security activity, plans that can increase visibility and reinforce cooperation with local police in a smooth way will provide a positive effect to the safety on campus.