• Journal of Electrical Engineering and Technology
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• 제3권2호
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• pp.243-253
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• 2008

This paper deals with the analysis, design, and implementation of a single phase AC-DC Zeta converter with high frequency transformer isolation and power factor correction(PFC) in two modes of operation, discontinuous current mode of operation(DCM), and continuous current mode of operation(CCM). A Digital Signal Processor(DSP) based implementation is carried out for validation of the Zeta converter developed design in discontinuous mode of operation. A comparison of both modes of operation is presented for a 1kW power rating from the point of view of steady state and dynamic behavior, power quality, simplicity, control technique, device rating, and converter size. The experimental results of a developed prototype of Zeta converter are presented for validation of the developed design. It is observed that CCM is most suitable for higher power applications where it requires some complex control and sensing of the additional variables.

• 한국전자통신학회논문지
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• 제16권1호
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• pp.125-134
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• 2021

영화 산업의 빠른 발전으로 영화의 제작 수가 급격하게 증가하고 있으며, 영화 추천 시스템은 관객들의 과거 행동이나 영화 후기에 기반하여 관객들의 선호도를 예측하여 영화의 선택에 도움을 주고 있다. 본 논문은 평점의 평균과 편향의 보정을 이용하여 잠재요인 모델에 기반한 영화 추천 시스템을 제안한다. 특이값 분해 방법이 평점 매트릭스 분해에 사용되고, 통계 경사 하강법이 최소자승 손실 함수의 파라미터 최적합에 사용된다. 그리고 평균 제곱근 오차를 사용하여 제안한 시스템 성능을 평가한다. Surprise 패키지를 이용하여 제안한 시스템을 구현 하였으며, 모의실험 결과는 평균 제곱근 오차가 0.671이며, 다른 논문에서 방법에 비하여 좋은 성능을 가진다는 것을 확인하였다.

• 대한가정학회지
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• 제46권9호
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• pp.87-97
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• 2008

This study was conducted to develop the Home Literacy Environment Rating Scale(HLERS) and to analyze its item discrimination, reliability, and validity. The participants of this study were 438 parents whose children were three to five years old. The item discrimination, determined by comparing the highest and lowest group using Chi-square($x^2$) and Cramer's V, was found to be satisfactory. The Cronbach's $\alpha$ for internal consistency reliability was .78. Factor analysis revealed that the structure of the HLERS consisted of three factors: 'reading books,' 'reading behavior and modeling of parents' and 'literacy learning.' The concurrent validity was also identified by correlation between the HLERS and two sub-tests of EC-HOME. In conclusion, these results demonstrated that the Home Literacy Environment Rating Scale is reliable and valid to examine the home literacy environment for Korean families.

• 수산해양교육연구
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• 제29권2호
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• pp.436-446
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• 2017

This study was performed to verify the validity and utility of the Korean Behavior Rating Inventory of Executive Function-Preschool Version(BRIEF-P). The BRIEF-P is one of the most used instruments to measure Executive Function(EF) and a teacher-rating assessment method designed to measure the executive function of preschoolers(age 2-5). A total of 200 preschoolers(104 boys, 96 girls; recruited aged 3 to 5years) participated. Confirmatory factor analysis was carried out to evaluate the model structure. Correlation analysis was done to verify the concurrent validity. In the results, the model fit indexes were good with the five BRIEF-P subscales (that is, inhibit, shift, emotional control, working memory, plan/organize). The internal consistency of the BRIEF-P five subscales were supported. As a results, the Korean Behavior Rating Inventory of Executive Function-Preschool Version(BRIEF-P) was confirmed to be a reliable and valid assessment tool to measure executive function in preschoolers.

• 산업경영시스템학회지
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• 제45권4호
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• pp.70-78
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• 2022

Recently, elevator inspection and self-examination were strengthened through the revision of the Elevator Safety Management Act, but there have been no significant reduction in serious accidents and major failures. Therefore, the government intends to lay the foundation for reflecting the safety quality rating system, which adjusts the elevator inspection cycle, as a policy to induce safety management of preemptive and active management entities. This study systematically reviewed and classified the safety quality rating system for elevator inspection cycle adjustment in previous studies, collected expert opinions, and reconstructed the key items into realistic evaluation items, and evaluated and scored the relative importance of each factor through the AHP technique.

• 생물정신의학
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• 제12권2호
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• pp.189-195
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• 2005

Objects:Some studies have suggested that brain-derived neurotrophic factor(BDNF), one of the most important neurotrophins, is involved in pathophysiology of depression and suicide. This study was performed to determine whether there is an abnormality in plasma BDNF concentration in suicidal attempters. Methods:The subjects were 71 suicidal attempters who visited emergency rooms in multi-medical centers. All subjects had been interviewed by using Structured Clinical Interview for DSM-IV(SCID), Hamilton Depression Rating Scale(HDRS), Young Mania Rating Scale(YMRS), and Positive And Negative Syndrome Scale(PANSS). The severity of the suicidal behavior was measured by Lethality of Suicide Attempt Rating Scale(LSARS) and Risk-Rescue Rating(RRR) system. Seventy-one age, sex, and diagnosis matched non-suicidal psychiatric patients who were consecutively admitted to a psychiatric ward during the same period recruited as psychiatric controls. They were drug-naive or drug-free at least more than 2 months. In addition, 80 healthy controls were randomly selected as normal controls. Plasma BDNF level was measured by the enzyme linked immunosorbent assay(ELISA) methods. Results:In overall F-test, differences of the plasma BDNF levels among the groups were statistically significant(F=20.226, p<0.001). In the multiple comparisons(Scheffe), while mean levels of plasma BDNF between normal controls and non-suicidal psychiatric patients were similar(p=0.984), the BDNF levels of suicidal attempters were lower than those of other two groups(p<0.001). LSARS and RRR did not reveal any significant correlations with BDNF levels in suicidal attempters. Conclusion:These results suggest that reduction of plasma BDNF level is related to suicidal behavior and BDNF level may be a biological marker of suicidal behavior.

• 한국강구조학회 논문집
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• 제19권1호
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• pp.1-13
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• 2007

강사장교의 거더와 주탑은 축력과 모멘트를 동시에 받는 보-기둥 부재이기 때문에 단일 힘을 고려하는 일반도로교의 내하율 산정식은 강사장교의 거더와 주탑에 적용할 수 없다. 현재, 사장교의 거더와 주탑에 적용 가능한 이론적인 내하율 산정방법은 아직 정립되지 않았다. 본 논문에서는 축력과 모멘트를 동시에 받는 부재의 상관공식을 적용하여 강사장교 거더와 주탑의 내하율을 산정하기 위한 식을 제안하였다. 영향선해석을 수행하여 각 부재에 압축력 최대, 정 및 부모멘트 최대의 경우에 활하중 재하 형태를 결정하였고 각 부재의 내하율 산정절차를 정리하였다. 제안된 내하율 산정방법의 타당성을 검증하기 위하여 실교량 모델인 돌산대교에 대한 적용예를 제시하였다. 일반도로교의 내하율 산정식은 돌산대교 거더와 주탑의 내하율을 과대평가 하였으며, 제안된 내하율 산정식은 축력과 모멘트를 동시에 지지하는 사장교 거더와 주탑의 거동을 적절히 반영하였다.

• 한국실내디자인학회논문집
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• 제15권4호
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• pp.21-28
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• 2006

To promote environmentally responsible architectural practice, many nations have established their own green building rating system. Among other criteria, recently the indoor environmental quality section has been paid great attention due to Sick Building Syndrome, as this believed to caused by polluted indoor environment. In this context, indoor environmental quality is one of very important sections of each green building rating system and closely related to the very happiness of building users. The goal of this research is to compare and analyze the indoor environmental sections of three green building rating systems, GBCC, LEED v2.1, and BREEAM Office 2005, and find a direction for the improvement of GBCC. First, the three rating systems are analyzed in general to compare the importance of indoor environmental factors in each system. Second, the indoor environmental factors are reclassified within related sub-categories for the comparable analysis. Finally, based upon the comparable analysis, directions for the improvement of GBCC are as follows: 1. GBCC's h4r Environment Section needs to clarify its VOCs criteria based upon types of finish materials. 2. Sound Environment Section's noise control criteria needs to be revised based upon types of building usages and application method. 3. An indoor lighting related section needs to be included in GBCC, as even though light is the one of the most important factors in indoor environment, it has not been included in GBCC yet. 4. The sub-section of Confortable Indoor Environment Section related to the resting space and the universal accessibility are not in accord with the goal of green building rating system. These items need to be dealt within general building codes. 5. The rating evaluation structure and process need to be streamlined.

• 한국게임학회 논문지
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• 제19권5호
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• pp.15-38
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• 2019

국내 등급분류 제도는 '검열성' 및 '모호성' 등 많은 한계를 보이며 산업의 발전을 저해하는 요소로 지적되고 있다. 문화체육관광부를 비롯한 관련 기구에서는 여러 자구적인 노력을 추진하고 있으나 여전히 많은 부분에서 학술적 논의가 필요한 것으로 보인다. 따라서 본 연구에서는 게임물 등급분류제도의 내용과 그 한계점을 검토하고, 국외의 유사 제도를 분석하여 우리 제도가 개선되어야 할 방향을 제시하고자 한다. 본 연구결과는 건강한 게임문화 정착과 게임산업 발달에 부분적으로 기여할 수 있을 것으로 기대된다.

• 한국정밀공학회지
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• 제12권7호
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• pp.66-73
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• 1995

Rating systems of bevel gears(straight, spiral, and zerol bevel gears) which are commonly used as power transmission devices for non-papallel axes are developed on the personal computer, which analyze and/or evaluate the gear design and the service performance at the point of view of strength and durability. The typical considerations of the ratings are the bending strength, the surface durability, and the scoring resistance. The ratings are carried out using the reliable standards of AGMA & Gleason Works. Therefore, the system is built so that the variables or factors considered differently in those standards and the strength, dura- bility, and scoring partially in Gleason are appraised seperately by each method, and a series of the estimation processes is integrated into the system so as to compare each result. The developed rating systems can be used in the initial stage of gear design process, and also a better design can be performed by the evaluation of the initial design at the view point of gear strength and durability. Additionally, it is useful for the trouble-shooting of bevel gear system and to the purpose of introducing the methods for maintaining design strength in service, with appraising the gear strength after design or with appraising the influencing factor as a whole. Therefore, this rating systems can help the aim of design automation of bevel gears.