• 대한임상독성학회지
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• 제15권2호
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• pp.116-121
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• 2017

Purpose: The aim of this study was to compare the toxicologic profiles and outcome of poisoned patients by comparing the data obtained through telephone counselling, each provided by emergency medical information center (1339) and emergency dispatch center (119). Methods: We analyzed the telephone-based poison exposure data before and after Seoul 1339 merged to 119. We compared the Seoul 1339 call response data in 2008 with Seoul and Busan 119 call response data between 2014 and 2016. We analyzed the changes in the trend and quality of data obtained, as well as the quality of service provided by each center before and after this reallocation, by comparing the data each obtained through telephone counselling. Results: The data was collected for a total of 2260 toxin exposure related calls made to Seoul 1339 in 2009, and 1657 calls to 119 in Seoul and Busan between 2014 and 2016. Significant difference was observed for age, sex, and reason for exposure to toxic substance between the two groups. Conclusion: After the integration of 1339 with 119, 119 focused on role of field dispatch and hospital transfer, lacking the consulting on drug poisoning. Moreover, data on exposure to toxic substances at the pre-hospital stage indicate that drug information and counseling are missing or unknown. In addition, first aid or follow-up instructions are not provided. Thus, systematic approach and management are required.

• 한국가스학회지
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• 제19권5호
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• pp.13-19
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• 2015

본 연구에서는 보다 현실적인 파쇄균열 전파를 묘사하기 위해 수압파쇄균열 전파 모델을 개발하였다. 이 모델에서는 두 가지 균열 전파 기준을 적용하였다. 첫 번째는 균열의 발생각을 결정하기 위한 최대 접선응력 기준과 두 번째는 파쇄균열의 자연균열 통과 여부 기준이다. 본 모델의 검증 결과, 수압파쇄균열이 자연균열을 통과하는 양상이 실험값과 동일함을 확인하였다. 균열의 전파에 직접적인 영향을 미치는 요소인 최대수평응력 방향, 균열면의 마찰계수, 자연균열의 방향성에 대한 민감도 분석 결과, 이론적 기준에 적합하게 균열의 전파 방향과 통과 여부가 결정되는 것으로 나타났다. 기존의 수직 판형 균열 전파 모델과 본 모델을 비교하여 균열의 연결성과 유정 자극부피 측면에서 차이가 있음을 확인하였다.

• 전력전자학회논문지
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• 제10권4호
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• pp.313-322
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• 2005

본 논문은 복공진 인버터를 적용한 250[W] 메탈핼라이드램프를 구동하기 위한 고역률 전자식 안정기를 설계하고 구현하였다. 제안된 전자식 안정기는 역률 개선 회로기능을 갖는 부스트 능동 PFC 회로와 하프 브리지 복공진형 인버터로 구분된 2개의 전력처리단으로 구성되어 있다. 회로 기본동작원리 및 회로 해석은 무차원화 파라미터를 도입하여 범용성을 부여하여 도식적으로 나타내었다. 음향공명을 제거하기 위해 타이머 IC와 구동 IC로 구성된 간단한 주파수 제어기를 구현하였다. 실험을 통해 복공진 인버터를 적용한 고역률 메탈핼라이드램프용 전자식 안정기가 안정적으로 동작함을 확인하였다

• 기술혁신학회지
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• 제7권1호
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• pp.89-110
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• 2004

Home networks consist of two or more home appliances or communication devices enabling the mutual data communication between appliances such as personal computers, refrigerators, phones, television sets, personal digital assistants(PDA), etc. There are three factors that create demand for the home network services. The first factor is development of technology. Second, on the demand side, consumer demand for the home appliances having access to the Internet is in the increase. Finally, producers need a strategy to deal with the problem of market saturation. Home networks are emerging markets. They are unique in that they unite information technologies with home appliances that provide new services. in this paper we study the main attributes of home network services and analyze consumers' preferences for them. However, it is not quite possible to use the revealed preference approach since the home network market is still at an incipient stage. We therefore use the conjoint analysis method using stated preference data. conjoint analysis has been widely use in the area of marketing for evaluating consumer preferences for new products and services. it presents a hypothetical product to the respondents along with the product's attributes and their levels. The respondents are asked to either rank each alternative or choose between several hypothetical products. By estimating consumers' willingness to pay for the attributes of the home network services and analyzing consumers' preferences, we predict the pattern of the development of the home network services and related technologies along various quality dimensions. Based on the estimation results, we draw policy implications for the national- and company-level strategy.

• Nuclear Engineering and Technology
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• 제21권1호
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• pp.1-11
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• 1989

원자로 정지동안에도, 잔열제거계통은 그 기능이 계속 유지되어야 하나, 실제로 가압 경수로에서 냉각상실고가 많이 발생되어 있다. 본 논문은 원자로 정지중의 냉각기능상실을 예방하고, 또한 냉각기능상실로 인한 노심손상의 중대성을 완화시키기 위한 대책을 강구하기 위한 시도로서, 전형적인 가압경수로에 대한 사고/고장 수목과 운전원실수 확률을 위한 HCR 모델, 초기 사상의 빈도를 위한 2단계 bayesian 방법 및 고장난 계통의 회복 활률을 위한 계단함수 모델 등을 이용한 원자로 정지 위해도 모델을 개발하여, 잔열제거계통의 신뢰도를 분석하였다. 그 결과는 원자로가 정지 중일 때의 위해도가 운전중일 때 이것에 비해 별로 낮지 않은 것으로 나타났으며, 몇 가지의 설계개선을 통하여 냉각기능상실로 인한 노심 손상확률을 상당히 낮출 수 있는 것으로 나타났다.

• Nutrition Research and Practice
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• 제13권6호
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• pp.498-508
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• 2019

BACKGROUND/OBJECTIVES: Lower circulating 25-hydroxyvitamin D [25(OH)D] levels are associated with a higher risk of hypertension (HTN); however, it remains unclear whether the relationship is causal. We aimed to evaluate the causal effects of circulating 25(OH)D levels on the prevalence of HTN in the Korean population using the Mendelian randomization (MR) approach. SUBJECTS/METHODS: Epidemiological data, serum 25(OH)D data, and genomic DNA biospecimens were obtained from 2,591 participants, a subset of the study population in the Korea National Health and Nutrition Survey 2011-2012. Five 25(OH)D-related single nucleotide polymorphisms (SNPs; DHCR7 rs12785878, CYP2R1 rs10741657, CYP2R1 rs12794714, CYP24A1 rs6013897, and GC rs2282679), identified a priori from genome-wide association studies, were used as instrument variables (IVs) for serum 25(OH)D levels. In the MR analysis, we performed IV analyses using the two-stage least squares method. RESULTS: In the observational analysis, circulating 25(OH)D levels were found to be inversely associated with the HTN prevalence in ordinary least squares models (odds ratio: 0.97, 95% confidence interval: 0.96, 0.99) after adjusting for the potential confounders. There were differences in the circulating 25(OH)D levels across genotypes of individual SNPs. In the MR analysis, using individual SNPs as IVs, 25(OH)D levels were not associated with the HTN prevalence. CONCLUSIONS: We found no association between genetically determined circulating 25(OH)D levels and HTN in Korean adults. Our results are listed owing to the relatively small sample size and possible weak instrument bias; therefore, further studies are needed to confirm these results.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.46-53
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• 1999

As of July 1999, i,185 lomocotives(excluding metropolitan area electric locomotives) are in Korean National Railroad(KNR). With this limited number of resources assigning locomotives to each trains of timetable is very important in the entire railway management point of view because schedule can be regarded as goods in transportation industry. On a simple rail network, it is rather easier to assign proper locomotives to trains with the experience of operating experts and get optimal assignment solution. However, as the network is getting bigger and complicated, the number of trains and corresponding locomotives will be dramatically increased to rover all the demands required to service all of the trains in timetable. There will be also numerous operational constraints to be considered. Assigning proper locomotives to trains and building optimal cyclic rotations of locomotive routings will result in increasing efficiency of schedule and giving a guarantee of more profit. The purpose of this study is two fold: (1) we consider a planning-level locomotive scheduling problem with the objective of minimizing the wasting cost under various practical constraints and (2) development of implementation prototype program of its assigning result. Not like other countries, i.e. Canada, Sweden, Korean railroad operates on n daily schedule basis. The objective is to find optimal assignment of locomotives of different types to each trains, which minimize the wasting cost. This problem is defined on a planning stage and therefore, does not consider operational constraints such as maintenance and emergency cases. Due to the large scale of the problem size and complexity, we approach with heuristic methods and column generation to find optimal solution. The locomotive scheduling prototype consists of several modules including database, optimization engine and diagram generator. The optimization engine solves MIP model and provides an optimal locomotive schedule using specified optimization algorithms. A cyclic locomotive route diagram can be generated using this optimal schedule through the diagram generator.

• 터널과지하공간
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• 제28권6호
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• pp.651-669
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• 2018

본 연구에서는 유전자 프로그래밍과 개체군집최적화기법을 이용하여 픽 커터의 비에너지를 예측하기 위한 모델을 제안하였다. 기계굴착장비의 굴진성능을 평가하는 것은 터널의 설계 초기 단계에서 매우 중요하며, 비에너지를 이용한 기계 굴착장비의 굴진성능평가방법은 모든 기계굴착공법에 적용될 수 있는 표준화된 방법이다. 본 연구에서는 코니컬형상의 픽 커터가 암석을 절삭할 때 요구되는 비에너지와 암석의 강도특성, 절삭조건 간의 상관관계를 분석하고자 하였으며, 선행연구를 통해 총46개의 선형절삭시험 결과를 수집하여 분석에 활용하였다. 본 연구에서 제안한 예측모델을 이용하여 산정된 픽 커터의 비에너지는 다중선형회귀분석에 비해 작은 평균제곱오차를 나타내었으며, 결정계수 또한 본 연구에서 제안한 모델이 다중선형회귀분석에 비해 우수한 예측결과를 나타내는 것을 확인할 수 있었다.

• 아태비즈니스연구
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• 제12권1호
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• pp.41-56
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• 2021

Purpose - This empirical study examined the influence of post-communist countries sociol-political factor of freedom of expression preconditioning, and trust in agency, mediating performance expectancy of social media users representing the citizens' behavioural intention to utilize social media in a post-communist country, the case of Mongolia. Design/methodology/approach - This research collected 403 valid survey data from citizens those who use social media in Mongolia. The study used Partial Least Squire (PLS) analysis with the research conceptual model founded on the UTAUT model. Findings - The study shown that citizens in post-communist, they strongly willing freedom of expression, which driving as a positive precondition factor, and this has an indirect positive influence, and trust in agency mediates to enhance performance expectancy. Social influence, and effort expectancy factors have direct positive influence on the intention to use of social media systems in the public sector domain of Mongolia. Research implications or Originality - This research proposed a new model to test citizens' intention to use social media as a communication tool to engage with public organizations in the pre-adoption stage of post-communist countries. Theoretically, this research builds up to the unique theoretical contribution with social media by examining a new social media-based third-party intercommunication medium, incorporating intent to utilize for citizens with government in post-communist countries. Practically, this article lays out the directions to aid social media usage for government sector with concerning citizens intentions in the post-communist situation.

• 대한건축학회논문집:계획계
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• 제34권12호
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• pp.135-144
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• 2018

This paper deals with preservation and restoration as a universal approach to conserve architectural heritage. The questions on how to preserve or restore them have been always major issues for many old buildings. Reading changes in ways of the thinking to solve such matters in the past helps to grasp the fundamental concepts to conserve cultural heritage at this point in time. The method is an important stage that leads to change our current attitude. Both the ways of the thinking for preservation and restoration should be re-interpreted to preserve memory or to restore identity depending on the current situation, and even should no longer be understood as two opposite options. Therefore, this paper focuses on the epistemological notion and reveals the origin and premise of modern historical perception that has become disconnected from the past works. By taking the writings of $Eug{\grave{e}}ne$-Emmanuel Viollet le Duc, John Ruskin, and Camillo Boito into consideration, the thesis shows that their thought, in the common denominator of the time, is a kind of reflection of consciousness according to particular historical contexts and that their ideas echo three dialectical paradigms derived from past and present, memory and forgetfulness, and history and truth.