• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.1-10
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• 1998

Testing high reliability devices under nomal operating condition is difficult, because the devices are not likely to fail in the relatively short time available for tests. For most applications it is necessary to accelerate the causes of failure by increasing a stress above its nomal value. Previous accelerated life test(ALT) plans have shown how to find optimum allocation, lowest stress and sample size subject to minimizing the variance of mean life estimator. In these ALT plans, the highest acceptable test-stress was assumed to be specified in advance by the experimenter but there is no guidance for selecting it. This assumption is, however, inappropriate for many applications. Testing devices at too-high stress levels can invalidate the extrapolation model, or introduce failure mechanisms that are not anticipated under nomal operating conditions. In this paper, we propose new 4:2:1 compromise plans using Min-Max method to minimize this risk and present minimized test-stress levels(max, middle, min), and find sample allocation based on Min-Max 4:2:1 compromise plans. In result, we compare previous 4:2:1 compromise plans specified maximum test-stress with Min-Max 4:2:1 compromise plans minimized maximum test-stress.

• Journal of Korean Academy of Nursing
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• v.35 no.4
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• pp.680-685
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• 2005

Purpose. The purpose of the study was to categorize nursing students' subjectivity in their attitude toward their jobs, and thereby understand the differences among these attitude types. Methods. The study used a Q-method to measure nursing students' attitude toward jobs identity types. In-depth and objective interviews and literature review formed Q sample. The P sample consisted of 25 nursing students. Results. The results of the study show that nursing students can be categorized into three types, depending on their attitudes toward their jobs. The firs type, 'interest-oriented' students, strongly disagree to the follow-ing: giving priority to job over marriage, standing unfair treatment in the workplace, the importance of pro-motion opportunity, irresponsibility, and uncertainty. The 'reward-oriented' students, on the other hand, strongly disagree to the following: indifference to career prospects, employment-related relocation of residence, irresponsibility, standing difficulties, and compromises with others. The third type of nursing students is the possession-oriented students, who strongly disapprove of irresponsibility, refusal to compromise with reality, standing unfair job allocation or promotion and career uncertainty. Conclusions. The study on nursing college students' attitude toward their jobs is meaningful in the following aspects: First, the study clarifies nursing college students' attitudes toward their job by categorizing it. Second, the study confirms the changing attitudes of nursing students toward jobs with the change of times and calls for proper educational programs to foster healthy career attitudes. Third, proper decision-making as regards jobs and job allocation for nurses, or their career attitudes, is beneficial to individuals, the medical industry, and society.

• Journal of Preventive Medicine and Public Health
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• v.54 no.5
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• pp.360-369
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• 2021

Objectives: The purpose of this study was to investigate public preferences regarding allocation principles for scarce medical resources in the coronavirus disease 2019 (COVID-19) pandemic, particularly in comparison with the recommendations of ethicists. Methods: An online survey was conducted with a nationally representative sample of 1509 adults residing in Korea, from November 2 to 5, 2020. The degree of agreement with resource allocation principles in the context of the medical resource constraints precipitated by the COVID-19 pandemic was examined. The results were then compared with ethicists' recommendations. We also examined whether the perceived severity of COVID-19 explained differences in individual preferences, and by doing so, whether perceived severity helps explain discrepancies between public preferences and ethicists' recommendations. Results: Overall, the public of Korea agreed strongly with the principles of "save the most lives," "Koreans first," and "sickest first," but less with "random selection," in contrast to the recommendations of ethicists. "Save the most lives" was given the highest priority by both the public and ethicists. Higher perceived severity of the pandemic was associated with a greater likelihood of agreeing with allocation principles based on utilitarianism, as well as those promoting and rewarding social usefulness, in line with the opinions of expert ethicists. Conclusions: The general public of Korea preferred rationing scarce medical resources in the COVID-19 pandemic predominantly based on utilitarianism, identity and prioritarianism, rather than egalitarianism. Further research is needed to explore the reasons for discrepancies between public preferences and ethicists' recommendations.

• East Asian Journal of Business Economics (EAJBE)
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• v.10 no.4
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• pp.1-18
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• 2022

Purpose - Through the analysis and research of different characteristics and related mechanisms of live commerce anchors, this paper aimed to help live commerce anchors to strengthen their characteristic advantages, beautify the live broadcast environment, improve resource allocation and enhance business performance, so as to help live commerce anchors to achieve better high-quality development. Research design, data, and methodology - This study was conducted by sample survey method on 361 live commercial anchors who have experience in using major online shopping malls for more than one year. Data analysis methods were frequency analysis, confirmatory factor analysis, reliability analysis, correlation analysis, and structural equation model analysis. Result - Hypothesis 1 through Hypothesis 5 were all supported. The results of this study suggest that professionalism and mutual entertainment of live commercial anchors have a significant impact on business performance, survival strategy, resource allocation and environment selection. The resource allocation and environment selection of live commercial anchors play a mediating role in the professionalism and mutual entertainment of live commercial anchors on business performance and survival strategy. Conclusion -The results implied that the professionalism and inter entertainment of live commercial anchors have a positive impact on business performance and survival strategy. In the new situation, live commercial anchors should further improve their professionalism and mutual entertainment, so as to achieve better development.

• The Korean Journal of Applied Statistics
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• v.9 no.2
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• pp.161-169
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• 1996

In the design of the sampling, it is important to make a decision about the size of the sample to be selected from the population. We often have a problem to get the optical size of the sample to be considered for cost and time expended for selecting sample unit from highly skewed population. In this case, we give a graphical criterion with Take-all Stratum rate to choose a method and also illustrate the efficiency between the Neyman allocation and the cut-off method with real data.

• Communications for Statistical Applications and Methods
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• v.13 no.2
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• pp.327-341
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• 2006

Winkler (1990, 2001), Sitter and Skinner (1994), Wilson and Sitter (2002) present a method which applies linear programing to designing surveys with multi-way stratification, primarily in situation where the desired sample size is less than or only slightly larger than the total number of stratification cells. A comparison is made with existing methods both by illustrating the sampling schemes generated for specific examples, by evaluating sample mean, variance estimation, and mean squared errors, and by simulating sample mean for all methods. The computations required can, however, increase rapidly as the number of cells in the multi-way classification increase. In this article their approach is applied to multi-way stratification using real data.

• Restorative Dentistry and Endodontics
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• v.39 no.3
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• pp.164-171
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• 2014

Objectives: Designing in situ models for caries research is a demanding procedure, as both clinical and laboratory parameters need to be incorporated in a single study. This study aimed to construct an informative guideline for planning in situ models relevant to preexisting caries studies. Materials and Methods: An electronic literature search of the PubMed database was performed. A total 191 of full articles written in English were included and data were extracted from materials and methods. Multiple variables were analyzed in relation to the publication types, participant characteristics, specimen and appliance factors, and other conditions. Frequencies and percentages were displayed to summarize the data and the Pearson's chi-square test was used to assess a statistical significance (p < 0.05). Results: There were many parameters commonly included in the majority of in situ models such as inclusion criteria, sample sizes, sample allocation methods, tooth types, intraoral appliance types, sterilization methods, study periods, outcome measures, experimental interventions, etc. Interrelationships existed between the main research topics and some parameters (outcome measures and sample allocation methods) among the evaluated articles. Conclusions: It will be possible to establish standardized in situ protocols according to the research topics. Furthermore, data collaboration from comparable studies would be enhanced by homogeneous study designs.

• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.2883-2893
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• 2018

We suggest a stratified conditional unrelated question randomized response model to more efficiently estimate a sensitive character A when the population is composed of several strata. In that model, only the respondents who answered "yes" through randomization device which was consisted of a less sensitive character B and a question forcing to answer "yes" respond to our suggested model and we deal with two allocation problems of proportional allocation and optimal one. We expand the suggested model into two sample stratified conditional unrelated question model to cover the case of unknowing unrelated character and deduce minimal variance through optimal sample size of stratum h. Finally, we show that the suggested model is more efficiency than stratified unrelated models and the stratified Carr et al.'s model (1982) under some given conditions, and show numerically that the smaller the values ${\pi}_{h2}$ and ${\pi}_{hy}$, the more efficiency the fit of the model.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.40
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• pp.179-186
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• 1996

Previous researches on optimum ALT plans have shown how to find optimum allocation, lowest stress and sample size subject to minimizing the variance of mean life estimate. Those researches have assumed the censoring time constant. But under certain circumstances such assumptions may not be reasonable. In this paper the constraint on constant censoring time is relaxed, and censoring time is considered variable. If all other test parameters remain unvaried, the variance of the mean life estimate reciprocally increases of the censoring time. This idea in this paper extends to the optimum censoring time. Thus, this paper presents the optimal censoring time in such situations, and finds the optimal lowest stress and allocation based on that optimal censoring time.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.1
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• pp.40-43
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• 2005

This paper presents the minimization of the fuel cost by optimal allocation of P-Q generation in a three-bus sample system. Derivation of the system loss sensitivities by optimization technique is introduced. The loss sensitivities are substituted into the optimality conditions and the optimal P-Q allocation is computed to obtain the minimal fuel cost.