• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1053-1063
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• 2017

Power prediction is critical to improve power efficiency in Smart Grids. Markov chain provides a useful tool for power prediction. With careful investigation of practical power datasets, we find an interesting phenomenon that the stochastic property of practical power datasets does not follow the Markov features. This mismatch affects the prediction accuracy if directly using Markov prediction methods. In this paper, we innovatively propose a spatial transform based data processing to alleviate this inconsistency. Furthermore, we propose an enhanced power prediction method, named by Spatial Mapping Markov-Difference (SMMD), to guarantee the prediction accuracy. In particular, SMMD adopts a second prediction adjustment based on the differential data to reduce the stochastic error. Experimental results validate that the proposed SMMD achieves an improvement in terms of the prediction accuracy with respect to state-of-the-art solutions.

• 디지털융복합연구
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• 제19권6호
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• pp.399-408
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• 2021

본 연구의 목적은 시뮬레이션기반 실습과 임상실습이 간호대학생의 비판적사고와 간호과정자신감의 미치는 효과를 확인하고자 수행되었다. 본 연구는 D대학교 간호학과 4학년 103명(대조군 51명, 실험군 52명)을 대상으로 비동등성 전·후 설계를 이용한 유사실험연구이다. 수집된 자료는 SPSS 23.0 프로그램을 이용하여 분석하였으며, 주요 연구결과는 다음과 같다. 시뮬레이션기반 실습을 경험한 학생이 임상실습을 경험한 학생에 비해 비판적사고성향(t=-3.28, p=.001)은 유의한 향상을 보였다. 간호과정자신감(t=-1.78, p=.079)은 유의한 차이는 없었으나 실제적용, 협업 일관성, 간호일관성에서 유의하게 높게 나타났다. 결과적으로 일부 유의한 차이는 없었으나 시뮬레이션기반 실습이 간호대학생의 비판적사고성향 및 간호과정자신감을 향상시키는 것으로 확인되어 임상실습과 더불어 자유로운 시뮬레이션 실습환경에서의 반복 연습과 표준화환자를 활용한 시뮬레이션기반 실습 연구가 필요할 것으로 생각된다.

• 대한기계학회논문집B
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• 제22권11호
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• pp.1610-1624
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• 1998

An axisymmetric jet is forced with two helical fundamental waves of identical frequency spinning in opposite directions and an additional axisymmetric sub harmonic wave. The subharmonic component rapidly grows downstream from subharmonic resonance with the fundamental, significantly depending on the initial phase difference. The variations of the subharmonic amplitude with the initial phase difference show cusp-like shapes. The amplification of the sub harmonic results in 'vortex pairing of helical modes'. Furthermore, azimuthal variation of the amplification induces an asymmetric jet cross-section. When the initial subharmonics is imposed with an initial phase difference close to a critical value, the jet-cross section evolves into a three-lobed shape. One lobe is generated by the enhanced vortex pairing and the other two lobes are generated by the delayed vortex pairing. Thus, it is confirmed that the initial phase difference between the fundamental and the subharmonic plays an important role in controlling the jet cross-section.

• 한국경영과학회지
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• 제26권4호
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• pp.1-21
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• 2001

The purpose of this stuffy is to derive critical success factors for ERP system implementation by integrating managerial, technical. human resource and organizational culture factors welch have been proposed as influencing factors for the performance of ERP system implementation in previous studios. Especially, this stuffy divides ERP system implementation process into preparation stave, implement stage and settle-down and stabilization stave, and then derives critical success factors in each stage. The data for empirical analysis of the research model are collected from 64 companies and the respondents for questionnaire consist of ERP system implementation project managers and user department managers in companies which have already operated it after ERP system installation. The main results of this study are as follows. First, it derives 27 success factors through comprehensive review of various factors which may affect ERP system implementation performance, and categorizes them into one of three stapes preparation stave, implement stage, and settle-down and stabilization stage. Second, the relationship between many success factors at each stave (preparation stave, implement stage, and settle-down and stabilization stave) and performance variables is tested. As a result, the significant correlations between many success factors at each stage and ERP system implementation performance are found, and the difference among success factors in the degree of influencing the system performance is significantly shown. finally, the relationship between process-oriented performance variables and result-oriented performance ones is tested. As a result, it is found that there is significant correlation between process-oriented performance variables except for one variable-project resource management appropriateness - and result-oriented performance ones. The theoretical contribution of this study is to derive a comprehensive model of critical success factors for implementing ERP system project from the system deve1opment life cycle perspective, and empirically test it through field survey with a wide range of data collection. And, the practical implication of this study is to present the desirable guidelines for performing ERP system implementation project successfully.

• 한국산학기술학회논문지
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• 제15권3호
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• pp.1515-1521
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• 2014

본 연구는 간호학생의 급성 심근경색증 간호에 대한 시뮬레이션 기반 교육을 적용하고 비판적 사고, 문제해결력 및 학업성취도의 효과를 규명한 단일군 전후 원시실험설계이다. 대상자는 총 137명이었으며 중재기간은 2011년 9월부터 10월까지 총 6주간 시뮬레이션 기반 교육을 시행하고 중재 전후를 평가하였다. 자료분석은 SPSS Win17.0을 사용하였고, 평균과 표준편차, Paired t-test, 피어슨 상관계수를 이용하였다. 연구 결과 시뮬레이션 기반 교육프로그램은 비판적 사고, 문제해결력 및 학업성취도를 향상시키는 것으로 나타났다. 비판적사고가 증대될수록 문제해결력은 향상되는 것으로 나타났다. 반면 비판적사고 능력과 문제해결력은 학업성취도와 유의한 차이가 없었다. 시뮬레이션 기반 교육프로그램은 간호학생의 실무능력을 향상시키기 위해 유용한 학습방법임을 알 수 있었고, 임상현장에서 흔히 접할 수 있는 다양한 사례의 시나리오를 개발하여 실습교육에 적극 활용할 필요가 있다. 이를 위해서는 더 다양하고 적절한 실습교육방법에 대한 개발과 운영이 필요할 것으로 보인다.

• 한국전기전자재료학회논문지
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• 제20권7호
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• pp.626-630
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• 2007

The AC loss is an important issue in the design of the high temperature superconductor (HTS) power cables and fault current limiters. In these applications, a cylindrical HTS conductor is often used. In commercialization of these apparatuses, AC loss is a critical factor but not elucidated completely because of complexities in its measurement, e.g. non-uniform current distribution and phase difference between currents flowing in an individual HTS tape. We have prepared two cylindrical conductors composed of a Bi-2223 tape with different critical current density. In this paper, the AC loss characteristics of the conductors have been experimentally investigated and numerically analyzed. The result show that the measured losses for two conductors are not dependent on both arrangements and contact positions of a voltage lead. This implies that most of loss flux is only in the conductors. The loss for the Bi-2223 conductor with low critical current density is in good agreement with the calculated loss from Monoblock model, whereas the loss measured for the Bi-2223 conductor with high critical current density doesn't coincide with the loss calculated from the Monoblock model. The measured loss is also different from numerically calculated one based on the polygon model especially in low transport current.

• Journal of Trauma and Injury
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• 제34권3호
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• pp.155-161
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• 2021

Purpose: The coronavirus disease 2019 (COVID-19) pandemic has necessitated a redistribution of resources to meet hospitals' service needs. This study investigated the impact of COVID-19 on a regional trauma center in South Korea. Methods: We retrospectively reviewed cases of polytrauma at a single regional trauma center in South Korea between January 20 and September 30, 2020 (the COVID-19 period) and compared them to cases reported during the same time frame (January 20 to September 30) between 2016 and 2019 (the pre-COVID-19 period). The primary outcome was in-hospital mortality, and secondary outcomes included the number of daily admissions, hospital length of stay (LOS), and intensive care unit (ICU) LOS. Results: The mean number of daily admissions decreased by 15% during the COVID-19 period (4.0±2.0 vs. 4.7±2.2, p=0.010). There was no difference in mechanisms of injury between the two periods. For patients admitted during the COVID-19 period, the hospital LOS was significantly shorter (10 days [interquartile range (IQR) 4-19 days] vs. 16 days [IQR 8-28 days], p<0.001); however, no significant differences in ICU LOS and mortality were found. Conclusions: The observations at Regional Trauma Center, Pusan National University Hospital corroborate anecdotal reports that there has been a decline in the number of patients admitted to hospitals during the COVID-19 period. In addition, patients admitted during the COVID-19 pandemic had a significantly shorter hospital LOS than those admitted before the COVID-19 pandemic. These preliminary data warrant validation in larger, multi-center studies.

• Tuberculosis and Respiratory Diseases
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• 제84권3호
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• pp.217-225
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• 2021

Background: Despite the proven benefits of dexamethasone in hospitalized coronavirus disease 2019 (COVID-19) patients, the optimum time for the administration of dexamethasone is unknown. We investigated the progression of COVID-19 pneumonia based on the timing of dexamethasone administration. Methods: A single-center, retrospective cohort study based on medical record reviews was conducted between June 10 and September 21, 2020. We compared the risk of severe COVID-19, defined as the use of a high-flow nasal cannula or a mechanical ventilator, between groups that received dexamethasone either within 24 hours of hypoxemia (early dexamethasone group) or 24 hours after hypoxemia (late dexamethasone group). Hypoxemia was defined as room-air SpO₂ <90%. Results: Among 59 patients treated with dexamethasone for COVID-19 pneumonia, 30 were in the early dexamethasone group and 29 were in the late dexamethasone group. There was no significant difference in baseline characteristics, the time interval from symptom onset to diagnosis or hospitalization, or the use of antiviral or antibacterial agents between the two groups. The early dexamethasone group showed a significantly lower rate of severe COVID-19 compared to the control group (75.9% vs. 40.0%, p=0.012). Further, the early dexamethasone group showed a significantly shorter total duration of oxygen supplementation (10.45 days vs. 21.61 days, p=0.003) and length of stay in the hospital (19.76 days vs. 27.21 days, p=0.013). However, extracorporeal membrane oxygenation and in-hospital mortality rates were not significantly different between the two groups. Conclusion: Early administration of dexamethasone may prevent the progression of COVID-19 to a severe disease, without increased mortality.

• Acute and Critical Care
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• 제33권4호
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• pp.238-245
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• 2018

Background: Infection by multidrug-resistant (MDR) pathogens leads to poor patient outcomes in intensive care units (ICUs). Contact precautions are necessary to reduce the transmission of MDR pathogens. However, the importance of the surrounding environment is not well known. We studied the effects of ICU relocation on MDR respiratory pathogen detection rates and patient outcomes. Methods: Patients admitted to the ICU before and after the relocation were retrospectively analyzed. Baseline patient characteristics, types of respiratory pathogens detected, antibiotics used, and patient outcomes were measured. Results: A total of 463 adult patients admitted to the ICU, 4 months before and after the relocation, were included. Of them, 234 were admitted to the ICU before the relocation and 229 afterward. Baseline characteristics, including age, sex, and underlying comorbidities, did not differ between the two groups. After the relocation, the incidence rate of MDR respiratory pathogen detection decreased from 90.0 to 68.8 cases per 1,000 patient-days, but that difference was statistically insignificant. The use of colistin was significantly reduced from 53.5 days (95% confidence interval [CI], 20.3 to 86.7 days) to 18.7 days (95% CI, 5.6 to 31.7 days). Furthermore, the duration of hospital stay was significantly reduced from a median of 29 days (interquartile range [IQR], 14 to 50 days) to 21 days (IQR, 11 to 39 days). Conclusions: Incidence rates of MDR respiratory pathogen detection were not significantly different before and after ICU relocation. However, ICU relocation could be helpful in reducing the use of antibiotics against MDR pathogens and improving patient outcomes.

• 한국융합학회논문지
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• 제12권11호
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• pp.467-473
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• 2021

본 연구는 플립러닝을 적용한 건강사정수업이 간호대학생의 자기주도 학습능력, 비판적 사고성향, 학업적 자기효능감에 미치는 효과를 확인하기 위한 연구이다. 경상북도 K시 일개 간호대학에서 플립러닝을 적용하여 건강사정을 수강하는 2학년 학생을 대상으로 하였으며, 단일군 전후 비교 연구이다. 최종분석은 104명을 대상으로 하였고, 사전 사후 차이는 대응표본검정으로 분석하였다. 그 결과 자기주도 학습능력(t=-3.23, p<.01), 비판적 사고성향(t=6.381, p<.001), 학업적 자기효능감(t=-4.62, p<.001) 모두 통계적으로 유의하게 증가하였다. 이 연구결과를 바탕으로 플립러닝 학습법이 간호대학생의 자기주도 학습능력, 비판적 사고능력, 학업적 자기효능감을 증진시키는 효과적인 프로그램임이 확인되었다. 플립러닝 학습범의 적용은 장기적으로는 교육환경을 개선하고 학생들의 능력을 강화시키는 역할을 할 것이다.