• The Transactions of the Korean Institute of Power Electronics
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• v.28 no.1
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• pp.22-29
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• 2023

A grid-connected inverter can be used in grid-connected or stand-alone modes. Generally, a grid-connected inverter operates in a grid-connected mode, but the inverter operates in stand-alone mode if grid faults occur. In the stand-alone mode, the grid-connected inverter must supply electric power to a critical load that needs to receive stable power even though grid faults occur. Generally, three-phase loads are used as critical loads, but a single phase is configured in some cases. In these conditions, the critical load is required to unbalance the load power consumption, which makes the three-phase load voltage unbalancd. This unbalanced voltage problem can cause fatal problems to the three-phase critical loads, and thus must be addressed. Hence, this paper proposes an algorithm to solve this unbalanced voltage problem by the individual phase current control. The proposed method is verified using Psim simulation and experiments.

• Journal of Korean Critical Care Nursing
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• v.13 no.1
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• pp.1-14
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• 2020

Purpose : The purpose of this study was to identify the factors influencing the general hospital nurses' confidence about the advance directives (ADs). Methods : This is a descriptive cross-sectional study. A total of 105 nurses were asked questions about characteristics, knowledge, attitude, learning needs, and confidence the about ADs, using structured questionnaires. Data were analyzed by descriptive statistics, t-test, ANOVA, Pearson's correlation coefficient, and multiple regression. Results : The mean scores of knowledge were 7.26±1.47; attitude, 2.80±0.31; learning needs, 4.22±0.62; and confidence, 2.57±0.74. It was observed that knowledge had significant correlations with attitude (r=.43, p<.001), learning needs (r=.29, p=.003), and confidence (r=.40, p<.001), and attitude had significant correlations with learning needs (r=.31, p=.001) and confidence (r=.45, p<.001). Using multiple regression analysis, it was found that confidence was significantly influenced by knowledge (β=.27, p=.007), attitude (β=.21, p=.043), and experience of nursing or counseling a patient who wrote ADs (β=-.19, p=.046). The explanatory power of this model was 37.9% (F=5.16, p<.001, R²=.379). Conclusions : These findings suggest the need to develop a program to enhance nurses' knowledge, positive attitude, and experience of nursing or counseling a patient who wrote ADs.

• Journal of the Korean Society for Library and Information Science
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• v.56 no.1
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• pp.27-45
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• 2022

Despite the increase in the number of international students residing in Korea, there is lack of research on their Everyday Information Seeking behaviors. This study investigated the information needs and information seeking behaviors of international students in Korea according to the settlement stages (before entry, initial settlement, and present) through Critical Incident Technology (CIT). International students in Korea reported their daily life-related information needs more frequently than their academic-related information needs. International students used multiple information sources for seeking information, such as websites, social media, and friends. Compared to websites, international students demonstrated higher satisfaction with interactive sources such as social media and friends. It was found that the language barrier is the biggest difficulty that international students experience during the information seeking process. Unfamiliarity with Korean society and culture were addressed as another difficulty. Based on the understanding of international students' information needs and seeking behaviors throughout the settlement stages, recommendations for helping international students search for information in their daily life were discussed.

• Quality Improvement in Health Care
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• v.9 no.1
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• pp.34-51
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• 2002

Background : The purpose for this study is to develop a critical pathway of bullectomy for spontaneous pneumothorax patients. Methods : For this study a conceptual framework of critical pathway was developed through a review of the literature including five critical pathways which are currently being used in USA, and opinions of the critical pathway development team members at Y university hospital. In order to identify the service contents required by these patients and to draw up a preliminary critical pathway, 33 cases of medical records of patients who had received bullectomy for spontaneous pneumothorax between September, 2000 to August, 2001 at the Respiratory Center of Y university hospital in Seoul was analyzed. Results : In order to test the clinical validity of the preliminary critical pathway, it was applied to ten patients who had received bullectomy for spontaneous pneumothorax from October, 2001 to December, 2001. The average discharge day was 4.89th post operation day, six patients discharged on the fourth post operation day which was the expected day, one patients discharged one day earlier than the expected day, one patient discharged three days later than the expected day, and one patient discharged six days later than the expected day. There were variances between the critical pathway and the actual practice. The variances came from tests, medications, and treatments. One item that showed variance in clinical applications was complemented, and three items were decided not to be corrected for the final determination of the critical pathway. Conclusion : This critical pathway is applicable to the care of patients with bullectomy for spontaneous pneumothorax, but it needs more clinical applications to grasp varied variances.

• Journal of Korean Academy of Nursing Administration
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• v.8 no.1
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• pp.85-95
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• 2002

The purpose of this study was to develope a critical pathway for the chemotherapy of non-small cell lung cancer patients and to identify its effects after implementation. Critical pathway was developed through 5 steps including content and clinical validity tests with collaborative efforts of nurses, clinicians, and other allied healthcare professionals with the aim of improving the quality of patient care, while minimizing cost to the patients. This paper was described an evaluation of the impact of a developed critical pathway on complication rate, length of stay, costs, the interval of treatment and patient satisfaction by nonequivalent control group posttest-only non-synchronized research design.Results were compared between the two groups of patients. There were no significant differences in demographic variables and the occurrence of bone marrow suppression between experimental group and control group(t=-0.01, p=0.992). There were statistically significant decreases in the average length of stay(t=-10.45, p=0.000), in the average cost(t=-2.988, p=0.004), and in the interval of treatment(t=-6.75, p=0.000) after implementation of the critical pathway compared to control group. Also, there was a statistically significant improvement of the patient satisfaction after implementation of the critical pathway compared to control group(t=4.57, p=0.000). This paper concludes that critical pathway in chemotherapy for lung cancer, implemented in the context of an general hospital, is the useful tool to shorten the hospital stay, reduce treatment costs, and improve the quality of life in cancer patients. Further study needs to be conducted to identify other clinical outcomes including job satisfaction, collaboration among health professionals and potential for use in education. Also, it is recommended that nurses should revise continuously the developed critical pathway through clinical implementation and maintain their role of patient advocacy through monitoring pathway compliance.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.2
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• pp.307-310
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• 2016

The operational cost for maintaining the superconductivity of high-temperature superconducting (HTS) cables needs to be reduced for feasible operation. It depends on factors such as AC loss and heat transfer from the outside. Effective operation requires design optimization and suitable operational conditions. Generally, it is known that critical currents increase and AC losses decrease as the operational temperature of liquid nitrogen ($LN_2$) is lowered. However, the cryo-cooler consumes more power to lower the temperature. To determine the effective operational temperature of the HTS cable while considering the critical current and AC loss, critical currents of the HTS cable conductor were measured under various temperature conditions using sub-cooled $LN_2$ by Stirling cryo-cooler. Next, AC losses were measured under the same conditions and their variations were analyzed. We used the results to select suitable operating conditions while considering the cryo-cooler's power consumption. We then recommended the effective operating temperature for the HTS cable system installed in an actual power grid in KEPCO's 154/22.9 kV transformer substation.

• Korean Journal of Child Studies
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• v.37 no.4
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• pp.83-99
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• 2016

Objective: The purpose of this study was to analyze correlation effect size between Basic Psychological Needs (BPN) and factors affecting BPN. Methods: This research was reviewed and synthesized systematically by meta-analyse. Fifty-eight published studies between 2008 and 2016 were sampled and the effect sizes were acquired. Results: The major findings were as follows. In general, medium correlation effect sizes were found. Competency among sub-factors of BPN showed highest effects. Parental factor was more related to BPN than school and individual factors. Parenting behavior and family psychological backgrounds were the most crucial factors in the parental factors. School adjustment was the most critical factor in the school factors. In school grade, the elementary school was more related to BPN than junior high school and high school. Conclusion: Based on these results, we suggest a number of components for parent-education programs, and information for future research.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.171-174
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• 2001

This study investigates the differences in critical dimensions which impact on operations and strategy in Internet EC of service related intangible product. For this purpose, services are newly classified by two selected dimensions such as 1)the proportion of substitute by on-line, and 2)the needs of interaction and customization. Secondly, on the classification of services, the differences of 1) customer needs of geographical accessibility, 2) needs of cooperation with off-line functions, and 3) customer purchase intention in Internet EC are tested among classified groups. Finally, implementations on operations and strategy in Internet EC are suggested, based on the results of analysis. Data are collected by the survey on the customer groups, and analyzed by statistical method, such as mean score plot, cluster analysis, and analysis of variance.

• International Journal of Quality Innovation
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• v.6 no.2
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• pp.116-130
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• 2005

While there are many successful cases where application of the TQM model has reaped substantial benefits (Corcoran, 1996; Hayday, 1996 and Massey, 1996), there is little attempt to further develop the TQM model to meet organisations' development needs. The purpose of this paper is introduce the process of development of a fit-for-purpose management system model to meet the development needs of the MTR Corporation Limited, a metro company of Hong Kong. The new management system model is formulated based on the previous research results, on TQM but comprises a new approach to bridging their pitfalls. The formulation of the TMS elements is based on the common factors of four National Quality Awards (Japan, USA, Europe and Australia) and the critical factors developed by seven studies. These studies include those of Saraph et al. (1989), Flynn et al. (1994), Anderson et al. (1995), Powell (1995), Handfield and Ghosh (1995), Black and Porter (1996), and Ahire et al. (1996).

• Educational Technology International
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• v.10 no.2
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• pp.1-27
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• 2009

Technology use can dramatically enhance teachers' performance in teaching and administrative tasks. An Electronic Performance Support System (EPSS) is a versatile tool that could provide just-in-time and on-the-job training when teachers need it. In order to design an effective EPSS for teachers, it is critical to identify their needs. This study used interviews to identify teachers' needs for technology by asking them about their workloads, the difficulty and time demands of tasks, and useful technologies. The implications of the findings for the design of an EPSS are discussed, including the necessity of an adaptive design of the EPSS.