• 방사성폐기물학회지
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• 제17권1호
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• pp.59-73
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• 2019

원자력발전소 운영 과정에서 발생되는 폐기물인 폐수지를 원천적으로 저감하기 위해, 새로운 폐수 정화기술을 개발하고 원전 폐수처리시스템에 가상적으로 적용하여 효용성을 평가하고자 하였다. 본 기술의 기본 원리는 폐수에 존재하는 주요 핵종이온들을 생물학적 혹은 화학적 방법을 통해 무기 결정광물로 바꾸는 방식이다. 실험실에서 폐수를 대상으로 회분식실험을 통해 핵종 제거율을 측정한 결과, 생물학적 방법은 24시간 이내에 세슘을 80% 이상 제거하였고, 화학적 방법은 95% 이상 세슘을 선택적으로 제거할 수 있었다. 그리고 원전 폐수에 존재하는 다른 주요 핵종들(Co, Ni, Fe, Cr, Mn, Eu)에 대해서도 초기 99% 이상의 높은 제거율을 보여 주었다. 우리는 APR1400 원자력발전소의 폐수처리시스템 공정에서 역삼투압(R/O)과 유기 이온교환수지 모듈 사이에 가상으로 본 기술 모듈을 설치하였다. 가상의 모듈 설치를 통한 기술적 타당성 평가를 통해, 우리는 폐수의 주요 핵종들이 90% 이상 선택적으로 제거되고 폐수지의 발생량이 대폭 감소된다는 결과를 얻을 수 있었다. 이러한 결과가 의미하는 바는 본 기술이 향후 미래에 상용화되었을 경우, 폐수지 관리 비용을 크게 감소시키고 수지 수명도 대폭 연장시킬 수 있어, 결과적으로 월성 방사성폐기물 처분시설의 저장고 포화시점을 최대한 늦출 수 있는 이점이 있다.

• Journal of Electrical Engineering and Technology
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• 제11권6호
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• pp.1664-1673
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• 2016

Lithium rechargeable cells are used in many industrial applications, because they have high energy density and high power density. For an effective use of these lithium cells, it is essential to build a reliable battery management system (BMS). Therefore, the state of charge (SOC) estimation is one of the most important techniques used in the BMS. An appropriate modeling of the battery characteristics and an accurate algorithm to correct the modeling errors in accordance with the simplified model are required for practical SOC estimation. In order to implement these issues, this approach presents the comparative analysis of the SOC estimation performance using equivalent electrical circuit modeling (EECM) and noise suppression technique (NST) in three representative $LiCoO_2/LiFePO_4/LiNiMnCoO_2$ cells extensively applied in electric vehicles (EVs), hybrid electric vehicles (HEVs) and energy storage system (ESS) applications. Depending on the difference between some EECMs according to the number of RC-ladders and NST, the SOC estimation performances based on the extended Kalman filter (EKF) algorithm are compared. Additionally, in order to increase the accuracy of the EECM of the $LiFePO_4$ cell, a minor loop trajectory for proper OCV parameterization is applied to the SOC estimation for the comparison of the performances among the compared to SOC estimation performance.

• 가정과삶의질연구
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• 제18권3호통권47호
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• pp.129-146
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• 2000

The purpose of this study was to investigation the variables that affected the generational transmission of household work form mothers to their married daughter. The subjects were 415 married daughters and their mothers living in Seoul and metropolitan areas. Statistical techniques used for this study included descriptive statistics and multiple regression analysis. The results of this study were as follows : First, married daughters; value of household work was significantly affected by total periods of marriage of daughters, daughter's perceived similarity to their mothers' household work. Second, married daughters' preference for household work was significantly affected by mother's occupation (managerialㆍprofessional), mother's perceived similarity, daughter's experience of living with mother-in-law, daughter's sex-role attitude, and daughter's perceived similarity. Third, married daughters' ability to do household work was significantly affected by total periods of marriage for mothers, mother's perceived similarity, and daughter's perceived similarity. Fourth, married daughters' standard of household work was significantly affected by mother's perceived similarity, daughter's occupation (techniciansㆍclerk), daughter's monthly income, and daughter's perceived similarity. Fifth, married daughters' usage level of home equipments was significantly affected by mother's birth order, mother's education, mother's occupation (managerialㆍprofessional), daughter's birth order, daughter's education, and daughter's monthly income. Sixth, Mother related variables had greater power than daughter related ones in explaining daughters' values and preference for household work value and preferences and usage of home equipments. In conclusion, married daughter's consciousness and performance of household work were significantly influenced by their mothers. It was especially so in daughter's usage level of hoe equipments. Accordingly, the results of this study support the existence of generational transmission of household work from mothers to their married daughters with regard to its consciousness and performance. Findings of this study have implications for counsellors, practitioners and educators.

• 한국도로학회논문집
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• 제18권4호
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• pp.29-35
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• 2016

PURPOSES : The new waste management policy of South Korea encourages the recycling of waste materials. One material being recycled currently is tire-derived fuel (TDF) ash. TDF is composed of shredded scrap tires and is used as fuel in power plants and industrials plants, resulting in TDF ash, which has a chemical composition similar to that of the fly ash produced from coal. The purpose of this study was to evaluate the properties of an asphalt concrete mix that used TDF ash as the mineral filler. METHODS : The properties of the asphalt concrete were evaluated for different mineral filler types and contents using various measurement techniques. The fundamental physical properties of the asphalt concrete specimens such as their gradation and antistripping characteristics were measured in accordance with the KS F 3501 standard. The Marshall stability test was performed to measure the maximum load that could be supported by the specimens. The wheel tracking test was used to evaluate the rutting resistance. To investigate the moisture susceptibility of the specimens, dynamic immersion and tensile strength ratio (TSR) measurements were performed. RESULTS : The test results showed that the asphalt concrete containing TDF ash satisfied all the criteria listed in the Guide for Production and Construction of Asphalt Mixtures (Ministry of Land, Infrastructure and Transport, South Korea). In addition, TDF ash exhibited better performance than that of portland cement. The Marshall stability of the asphalt concrete with TDF ash was higher than 7500 N. Further, its dynamic stability was also higher than that listed in the guide. The results of the dynamic water immersion and the TSR showed that TDF ash shows better moisture resistance than does portland cement. CONCLUSIONS : TDF ash can be effectively recycled by being used as a mineral filler in asphalt, as it exhibits desirable physical properties. The optimal TDF ash content in asphalt concrete based on this study was determined to be 5%. In future works, the research team will compare the characteristics of asphalt concrete as function of the mineral filler types.

• Nuclear Engineering and Technology
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• 제38권3호
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• pp.259-276
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• 2006

As the use of digital systems becomes more prevalent, adequate techniques for software specification and analysis have become increasingly important in nuclear power plant (NPP) safety-critical systems. Additionally, the importance of software verification and validation (V&V) based on adequate specification has received greater emphasis in view of improving software quality. For thorough V&V of safety-critical systems, V&V should be performed throughout the software lifecycle. However, systematic V&V is difficult as it involves many manual-oriented tasks. Tool support is needed in order to more conveniently perform software V&V. In response, we developed four kinds of computer aided software engineering (CASE) tools to support system specification for a formal-based analysis according to the software lifecycle. In this work, we achieved optimized integration of each tool. The toolset, NuSEE, is an integrated environment for software specification and V&V for PLC based safety-critical systems. In accordance with the software lifecycle, NuSEE consists of NuSISRT for the concept phase, NuSRS for the requirements phase, NuSDS for the design phase and NuSCM for configuration management. It is believed that after further development our integrated environment will be a unique and promising software specification and analysis toolset that will support the entire software lifecycle for the development of PLC based NPP safety-critical systems.

• 전자공학회논문지
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• 제51권10호
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• pp.3-10
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• 2014

본 논문에서는 인지 기반 중첩 융합 네트워크 환경 하에서의 사용자의 위치정보를 토대로 사용자 단말기의 전력소모감소와 간섭신호의 저감효과를 극대화하기 위한 기본적인 D2D(device-to-device)시스템을 제시하고 무선 전송 환경에서의 시스템 성능을 분석하고자 한다. 단말기의 기능성이 좋아짐에 따라 스마트한 지능을 기반으로 자원의 효과적 활용에 적합한 개별 이종 네트워크의 특성분석과 특성을 반영하는 시스템 측면의 최적화가 중요하다고 할 수 있다. 본 논문에서는 사용자 이동특성에 기반하여 인접 단말기와의 직접 통신하는 절차를 구성하여 단말기 간 직접 통신에 다중안테나 기술을 적용할 경우 이에 따른 FER(frame error rate) 등의 성능특성을 살펴보고자 한다.

• 대한치과기공학회지
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• 제39권4호
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• pp.285-294
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• 2017

Purpose: This study was carried out in order to examine organizational commitment in dental technicians and turnover intention level according to it, and to analyze its effects. Methods: A self-reported questionnaire survey was carried out by having convenience sampling as 200 dental technicians. An analysis of the collected data was computationally processed by using SPSS Win 19.0 program. An analytical technique was made by using statistical techniques such as frequency & percentage, t-test, One-way ANOVA analysis. The following are the analytical results of the collected materials. Results: In consequence of analyzing organizational commitment level in research subjects, there was a significant difference in the items for age, task field, job position in charge, career in dental laboratory technology, and monthly income(p<.05). The average of the item for organizational commitment level stood at 3.29, thereby having been indicated to be high. As a result of analyzing turnover intention level in research subjects, there was a significant difference in the items for task field, job position in charge, career in dental laboratory technology, and monthly income(p<.05). The average of the item for turnover intention reached 3.04, thereby having appeared to be relatively high. As for a correlation between organizational commitment and turnover intention, all variables were shown to have inverse correlation at a significant level. In consequence of conducting regression analysis in order to analyze the influence of organizational commitment upon turnover intention, a factor of having the most impact on turnover intention appeared to be normative commitment. The test value of the model was statistically significant. The explanation power about this was indicated to be 26.9%. Conclusion : In the above findings, the dental technicians are considered to need to be immersed in work with a sense of mission in performing job in charge, to strive to possibly have an opportunity of achievement and self-growth, and to perform a research and development in a manpower management strategy such as turnover prevention.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권10호
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• pp.4883-4901
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• 2016

Energy efficiency in Wireless Sensor Networks (WSNs) is very appealing research area due to serious constrains on resources like storage, processing, and communication power of the sensor nodes. Due to limited capabilities of sensing nodes, such networks are composed of a large number of nodes. The higher number of nodes increases the overall performance in data collection from environment and transmission of packets among nodes. In such networks the nodes sense data and ultimately forward the information to a Base Station (BS). The main issues in WSNs revolve around energy consumption and delay in relaying of data. A lot of research work has been published in this area of achieving energy efficiency in the network. Various techniques have been proposed to divide such networks; like grid division of network, group based division, clustering, making logical layers of network, variable size clusters or groups and so on. In this paper a new technique of group based WSNs is proposed by using some features from recent published protocols i.e. "Energy-Efficient Multi-level and Distance Aware Clustering (EEMDC)" and "Energy-Efficient Multi-level and Distance Aware Clustering (EEUC)". The proposed work is not only energy-efficient but also minimizes the delay in relaying of data from the sensor nodes to BS. Simulation results show, that it outperforms LEACH protocol by 38%, EEMDC by 10% and EEUC by 13%.

• 한국안전학회지
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• 제37권2호
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• pp.35-42
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• 2022

When an accident occurs, the associated human activity is typically regarded as a "human error," or a temporal deviation. On the other hand, if the accident results in a serious loss or if it evokes a social issue, the person determined to be responsible may be punished with a "violation" of related laws or regulations. However, as Heinrich stated, it is neither appropriate nor reasonable in terms of probability theory and cognitive science to distinguish whether it is a "human error" or a "violation" with a criterion of resultant accident severity. Nonetheless, some in society get on the social climate to strengthen regulations on workers who have caused accidents, especially violations. This response can present a social issue due to the lack of systematic judgment procedure which distinguishes violations from human errors. The purpose of this study was to develop an objective and systematic procedure to assess whether workers' activities which induced industrial accidents should be categorized as violations rather than human errors. Various analysis techniques for the determination of violation procedure were investigated and compared using an analysis approach method. An appropriate technique was not found, however, for judging the culpability of intentional violations. As an alternative, this study developed the process of creating violations, based on cognitive procedure, as well as the criteria to determine and categorize an activity as a violation. In addition, the developed procedure was applied to cases of industrial accidents and nuclear power plant issues to test its practical applicability. The study demonstrated that the proposed model could be used to determine the existence of a violation even in the case of multiple workers who work simultaneously.

• 한국컴퓨터정보학회논문지
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• 제27권4호
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• pp.127-136
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• 2022

본 연구는 간호학전공 이론교과목을 온라인으로 수강한 간호대학생들의 학습 만족도와 학습 만족도에 영향을 미치는 요인을 파악하기 위해 시도되었다. 간호대학생 175명을 대상으로 온라인 학습만족도, 학습자 변인, 교수자 변인, 대인 상호작용 변인과 학습지원 변인에 대해 질문지를 이용하여 자료를 수집하였다. 온라인 학습 만족도의 평균은 3.99점(1점부터 5점까지 분포)이며, 온라인 학습 만족도에 대한 영향요인은 온라인 학습의 지속적 이용 의도, 학업성적, 교수자 변인, 학습지원 변인 중 학습평가 및 관리였으며, 이들 변수가 온라인 학습 만족도를 설명하는 설명력은 50.2%였다. 온라인 학습 운영의 주된 문제점으로 교수자 관련 내용이, 그리고 기술상의 문제로 안정적인 서버 구축과 음향 개선이 요구되었다. 간호대학생의 온라인 학습 만족도를 향상하기 위해 온라인 학습의 지속적 이용 의도와 학업 성취도를 높일 방안 마련과 교수자의 노력, 대학의 학습지원을 위한 세부적인 계획 및 적용이 필요하다.