• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.189-192
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• 2021

항적추적 기술에 딥러닝 기반 LSTM(Long Short-Term Memory) 모델을 적용하는 연구로서 기존의 항적추적기술의 경우, 항공기의 등속, 등가속, 급기동, 선회(3D) 비행 등 비행 특성에 따른 칼만 필터 기반의 LMIPDA를 활용한 실시간 항적 추적 시 등속, 등가속, 급기동, 선회(3D) 비행 가중치가 자동으로 변경된다. 이러한 과정에서 등속 비행 중 급기동 비행과 같이 비행 특성이 변경될 때, 항적 손실 및 항적 추적 성능이 하락하여 비행 특성 가중치 변경성능을 향상시킬 필요성이 있다. 본 연구는 레이더의 오차 모델이 적용된 시뮬레이터의 Plot과 표적을 딥러닝 기반 LSTM(Long Short-Term Memory) 모델을 적용하여 학습시키고, 칼만 필터를 활용한 항적추적 결과와 딥러닝 기반 LSTM(Long Short-Term Memory) 모델을 적용한 항적추적결과를 비교함으로써 미리 비행 특성의 변경과정을 예측하여 등속, 등가속, 급기동, 선회(3D) 비행 가중치변경을 신속하게 함으로써 항적추적성능을 향상하기 위한 연구이다.

• Computers and Concrete
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• 제30권5호
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• pp.301-310
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• 2022

Cement-based sensors have been widely used as structural health monitoring systems, however, their long-term sensing performance have not actively investigated. In this study, a deep learning-based methodology is adopted to predict the long-term piezoresistive properties of cement-based sensors. Samples with different multi-walled carbon nanotube contents (0.1, 0.3, and 0.5 wt.%) are fabricated, and piezoresistive tests are conducted over 10,000 loading cycles to obtain the training data. Time-dependent degradation is predicted using a modified long short-term memory (LSTM) model. The effects of different model variables including the amount of training data, number of epochs, and dropout ratio on the accuracy of predictions are analyzed. Finally, the effectiveness of the proposed approach is evaluated by comparing the predictions for long-term piezoresistive sensing performance with untrained experimental data. A sensitivity of 6% is experimentally examined in the sample containing 0.1 wt.% of MWCNTs, and predictions with accuracy up to 98% are found using the proposed LSTM model. Based on the experimental results, the proposed model is expected to be applied in the structural health monitoring systems to predict their long-term piezoresistice sensing performances during their service life.

• 아태비즈니스연구
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• 제11권3호
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• pp.107-122
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• 2020

Purpose - This paper investigates the relations among exploratory and exploitative supply chain management practices, competitive advantage, and firm performance. Design/methodology/approach - This study takes a hypothesis-generating study to capture the tradeoffs between exploration and exploitation and develops some hypotheses which involve the relations among SCM practices, competitive advantage, and short-term and long-term performance. Findings - Exploitative SCM practices have more positive effects on short-term performance rather than long-term performance, whereas exploratory SCM activities affect long-term performance. Further competitive strategy, environmental dynamism, and organizational slack moderates the relationship between SCM and performance. Exploitative SCM is more desirable when a firm uses low cost strategy, lacks slack resources, and faces stable environment, while exploratory SCM is more effective when a firm employs differentiation strategy, has slack resources, and confront dynamic environment. Research implications or Originality - In order to understand the performance effects of a variety of SCM practices, we should distinguish between exploitative and exploratory SCM activities. Further the relationship between SCM and performance may differ depending upon some contingent variables such as external environment, competitive strategy and organizational slack.

• 한국지진공학회논문집
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• 제17권3호
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• pp.117-125
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• 2013

Seismic isolation has been considered and utilized in various industries as a way to prevent huge damage on to structures by large earthquakes in various industries. The laminated Laminated rubber bearings is are most frequently used in seismic isolation systems. The structural Structural safety could not be assured unless the performance of the rubber bearing is not guaranteed for the life time of the structure under the consideration that the bearing is a critical structural member to sustain vertical loads in the seismically isolated structure. However, there are few studies on the deterioration problems of rubber bearings during their service life. The long term performance of the rubber bearings was not considered in past designs of seismically isolated structures. This study evaluates the long term performance and creep characteristics of laminated natural rubber bearings that are used in seismically isolated buildings. For the this study, a set of accelerated thermal aging tests and creep tests are were performed on real specimens. The experimental results show that the natural rubber bearings would have a stable change rate of change for durability under severe environmental conditions for a long time.

• Journal of Hospice and Palliative Care
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• 제24권1호
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• pp.26-35
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• 2021

Purpose: The purpose of this study was to determine the effects of awareness of good death and end-of-life care attitudes on end-of-life care performance in long-term care hospital nurses. Methods: This study used a cross-sectional study design. The participants were 147 nurses working at six long-term care hospitals with more than 200 beds in B city, South Korea. Data were collected using self-reported questionnaires, and analyzed with descriptive statistics, the t-test, analysis of variance, Pearson correlation coefficients, and multiple stepwise regression analysis using IBM/SPSS 26.0 for Windows. Results: The participants' awareness of good death, end-of-life care attitudes, and end-of-life care performance were positively correlated. The factors affecting end-of-life care performance were age, education level, awareness of good death, and end-of-life care attitudes; these variables explained 19.0% of end-of-life care performance. Conclusion: In order to improve long term care hospital nurses' end-of-life care performance, continuing education and training should be provided regarding awareness of good death and end-of-life care attitudes.

• Steel and Composite Structures
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• 제28권1호
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• pp.39-49
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• 2018

The concrete bridge decks are usually precast and in-situ assembled with steel girders with post-pouring joint in the construction practice of super-wide steel-concrete composite beam. But the difference of concrete age between the precast slabs and the post-pouring joint has been not yet considered for the long-term performance analysis of this kind composite beam. A simply supported precast-assembled T-shaped beam was taken as an example to analyze the long-term performance of steel-concrete composite beam with post-pouring joint. Based on the deformation coordination conditions of the old-new concrete deck and steel girder, a theoretical model for the long-term behavior of precast-assembled composite beam is proposed in this paper according to age-adjusted effective modulus method. Then, the feasibility of the proposed model is verified by the available test data from the Gilbert's composite beams. Parametric studies were preformed to evaluate the influences of the cross-sectional area ratio of the post-pouring joint to the whole bridge deck, as well as the difference of concrete age between the precast slabs and the post-pouring joint, on the long-term performance of the composite beam. The results indicate that the traditional method without considering the age difference would seriously underestimate the effect of creep and shrinkage of concrete bridge decks. The concrete age difference between the precast slabs and the post-pouring joint should be demonstrated for the life cycle design and long-term performance analysis of precast-assembled steel-concrete composite beams.

• 가정간호학회지
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• 제31권1호
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• pp.77-88
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• 2024

Purpose: This study aimed to develop and assess the impact of an integrated infection control education program on the awareness, attitudes, and performance of infection control among caregivers in long-term care facilities. Methods: Participants were recruited from two long-term care facilities with 25 caregivers in both the experimental group and the control group. This study used non-equivalent control group quasi-experimental pre-post design. The effectiveness of a developed Integrated Infection Control Education Program was evaluated based on infection control awareness, attitudes, and performance. Data were analyzed using SPSS/WIN 28.0 through descriptive statistics, chi-square tests, Fisher's exact tests, and independent t-tests. Results: There was a statistically significant difference in the degree of awareness (t=-5.00, p<.001), attitude (t=-4.91, p<.001), and performance (t=-6.66, p<.001) of infection control between the two groups. Conclusion: Given these results, the integrated infection control education program significantly improved infection control awareness, attitudes, and performance among caregivers in long-term care facilities. This study is noteworthy because it provided comprehensive education on infection control practices to caregivers in environments that are particularly susceptible to infections, especially following COVID-19. This educational program is actively utilized and validated in practice, it would enhance the infection control performance of caregivers, thereby reducing infection rates within facilities, shortening the length of stay for elderly residents in long term care facilities, and contributing to the reduction of healthcare costs.

• 재무관리연구
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• 제25권4호
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• pp.145-182
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• 2008

As the life expectancy increases resulting in the aged society, the post-retirement life became one of the most important concerns of people. The long-term investment vehicles such as retirement savings and pension plans have been introduced to meet such demand of society. This paper examines the impact of asset allocation strategies on the long-term investment performance. Because of the unusually long investment horizon and the compounding effect, a suboptimal asset mix in a retirement plan can be a very costly and irreversible mistake. Instead of relying on anecdotal evidence to evaluate the merits of different allocation strategies, this paper performs various tests including stochastic dominance tests using both actual data and Monte Carlo simulated data that best fit the historical experience. The results indicate 1) the long-term investments perform better than the short-term investments, 2) the optimal asset allocation strategy for the long-term investments should be highly equity dominated.

• 설비공학논문집
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• 제28권4호
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• pp.165-170
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• 2016

Long-term performance of the enthalpy exchange element is a topic of current interest due to the concern of possible performance degradation over time. In this study, a 350 CMH enthalpy recovery ventilator equipped with an enthalpy exchange element was installed in an office room, and the performance has been traced over the past 5 years. The appearance, overall dimension, thermal performance, leakage ratio and anti-bacterial performance were checked annually. Results showed that the change in thermal performance (sensible, latent and enthalpy efficiency) was negligible with periodic cleaning with an air gun. However, the leakage ratio increased with time, measuring 7.3% after 5 years. Anti-bacterial test revealed that no bacteria were found during the test period. The largest change in the dimension occurred at the middle location of the element, although the change was less than 2% of the initial value.

• 지역사회간호학회지
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• 제31권1호
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• pp.34-42
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• 2020

Purpose: The objective of this study was to identify whether spirituality mediates the relationship between empathy and elderly care performance among Long Term Care (LTC) hospitals nurses in Korea. Methods: The data collection was performed July 1st to August 31th, 2018. Participants were 119 nurses from three long-term care hospitals in Korea. Self-reported questionnaires were administered to assess general characteristics, empathy, spirituality and elderly care performance. The data were analyzed using descriptive statistics, t-test, one-way ANOVA, Pearson's correlation coefficients, and three-stage simple and multiple regression analysis as proposed by Baron and Kenny. Results: The level of elderly care performance of participants was significantly different based on age (F=3.92, p=.010) and nurse's position (t=-2.18, p=.031). Spirituality had a significant mediating effect on the relationship between empathy and elderly care performance (Z=3.64, p<.001). Conclusion: As spirituality completely mediates the relationship between empathy and elderly care performance, it is necessary to develop a nursing education program that applies spirituality and empathy and supports religious activities at an institutional level.