• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.165-167
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• 2018

본 논문은 다권선 변압기를 이용한 능동 셀 밸런싱 회로의 에너지 전달 효율을 향상시킬 수 있는 스위칭 방식을 제안한다. 다권선 변압기를 이용한 밸런싱 회로는 셀 당 하나의 스위치가 사용되며, 하나의 변압기 권선을 두 개의 셀이 공유하는 구조를 가져 다른 능동 셀 밸런싱 회로보다 소량의 능동 소자 및 수동 소자가 사용되는 장점을 갖는다. 이 밸런싱 회로는 직렬 셀 전압의 분포에 따라 에너지를 공급하는 소스 셀과 에너지를 받는 목표 셀을 선택하여 벅-부스트 및 플라이백 방식으로 동작한다. 하지만, 플라이백 동작에서 기존의 스위칭 방식을 사용할 경우, 변압기의 커플링 계수의 영향으로 인해 밸런싱 과정 중 비-목표 셀로 전달되는 에너지가 발생하게 된다. 이는 에너지 전달 효율을 감소시켜 셀 밸런싱 과정 중 새로운 셀 불균형 현상을 초래한다. 본 논문에서는 플라이백 동작에서 변압기의 커플링 영향을 최소화하여 셀 밸런싱을 효과적으로 수행할 수 있는 스위칭 방식을 제안하였다. 제안한 스위칭 방식의 성능은 1 W급 시작품을 이용한 실험을 통하여 검증되었다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.933-943
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• 2019

The purpose of this study is to identify determinants for preferred funeral methods depending on socio-economic characteristics. In South Korea, the Act on Funeral Services, Etc. categorizes funeral methods into burial, inurnment, and natural burial. This study empirically analyzes how and what socio-economic characteristics affect choices among these three categories. Data is collected from Social Survey 2017 and funeral facilities in the country. The data to be analyzed is developed in terms of a hierarchy which puts the burial and cremation methods in an upper class and the inurnment and natural burial methods in a lower class. Based on this data, a nested logit model is employed to conduct empirical analysis. The analysis indicates that those characteristics that have a statistically significant influence on preferred methods include gender, age, householder, marriage, satisfaction with life, class awareness, monthly income, housing type, housing tenure type, and living in city area. Each variable's modulus of calculated direct and cross elasticity need to be used to analyze the outcome of a nested logit model. In this study, the modulus of direct and cross elasticity are determined for the significant variables. The calculated direct elasticity is applied to analyze the likelihood of choosing each funeral method when there are changes in the significant variables. When a particular method has been selected, on the other hand, the cross elasticity is utilized to analyze changes to the likelihood of choosing the other methods. One of the most notable results is related to natural burial. In order to meet the demand for natural burial, it is necessary to provide more burial sites and raise awareness of natural burial. This will facilitate the efficient use of national territorial space.

• 한국체육학회지인문사회과학편
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• v.55 no.5
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• pp.375-385
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• 2016

This study aims to find out the effect of attributes for selecting physical education institutions for preschooler by the director of early childhood education institutions on relationship quality and loyalty. The subjects were 254 directors of early childhood education institutions, which offer visiting physical education of physical education institutions for preschooler located in Busan and Gyeongnam Province, using convenience sampling method. 244 questionnaires of them were used for analysis. First, among attributes for selecting physical education institutions for preschooler recognized by the directors of early childhood education institutions, instructors qualification and the image of the institution had a positive influence on relationship satisfaction and all the four variables of early childhood education institutions directors' attributes had a positive effect on relationship trust. Second, among the four variables of attributes for selecting physical education institutions for preschooler recognized by the directors of early childhood education institutions, instructors qualification, tuition fee, and the image of the institution had a positive influence on loyalty. Third, both the two variables of relationship quality of the director of early childhood education institutions toward preschool physical education institutions had a positive influence on loyalty.

• Journal of Korean Society of Transportation
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• v.29 no.6
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• pp.97-106
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• 2011

Mode choice model is an essential element for estimating- the demand of new means of transportation in the planning stage as well as in the establishment phase. In general, current demand analysis model developed for the mode choice analysis applies common parameters of utility function in each region which causes inaccuracy in forecasting mode choice behavior. Several critical problems from using common parameters are: a common parameter set can not reflect different distribution of coefficient for travel time and travel cost by different population. Consequently, the resulting model fails to accurately explain policy variables such as travel time and travel cost. In particular, the nonlinear logit model applied to aggregation data is vulnerable to the aggregation error. The purpose of this paper is to consider the regional characteristics by adopting the parameters fitted to each area, so as to reduce prediction errors and enhance accuracy of the resulting mode choice model. In order to estimate parameter of each area, this study used Household Travel Survey Data of Metropolitan Transportation Authority. For the verification of the model, the value of time by marginal rate of substitution is evaluated and statistical test for resulting coefficients is also carried out. In order to crosscheck the applicability and reliability of the model, changes in mode choice are analyzed when Seoul subway line 9 is newly opened and the results are compared with those from the existing model developed without considering the regional characteristics.

• Environmental and Resource Economics Review
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• v.15 no.2
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• pp.147-175
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• 2006

This paper attempts to incorporate three important factors-perceptions, behavior and valuation-in analysing consumers' responses to health risks from environmental pollutants. Using a survey sample of 500 consumers in the Chonbuk province area, this paper empirically investigated determinants of risk perceptions from using tap water as drinking water. Most consumers were considerably concerned about health risks from drinking tap water. Moreover, those subjective concerns were not random, but were systematically related to individuals' demographic variables such as age, gender, and family size. Those subjective beliefs also influenced respondents' purchase intentions on safer water bottles, in response to a contingent behavior question of presenting two types of water bottles. The technical risk information provided in the survey had significant effects on purchase intentions only when it was interacted with respondents' actual averting practice. In addition, the sample selection effects were present by eliminating respondents who decided not to purchase either of two types of water bottles. The potential selection bias had impacts on the coefficients of the price difference variable, and subsequently the estimates of the price increments for health risk reductions.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.279-284
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• 1996

To develop a selective medium for the isolation and the detection of leuconostocs from the various samples including fermented vegetables, ten strains of leuconostocs and seven strains of lactobacilli were tested for their sensitivity to various antibiotics. The basal-medium containing 5 ${\mu}g/ml$ of novobiocin inhibited the growth of lactobacilli completely, but not that of leuconostocs. On the basis of this result, a new selective medium was developed and to be named NLS medium. This medium contains 1% Tryptone (Difco), 0.1% Yeast Extract (Difco), 2% sucrose, 0.1% Beef Extract (BBL), 0.5% sodium acetate, 0.2% ammonium sulfate, 0.01% magnesium sulfate, 0.2% dipotassium phosphate, 0.05% sorbic acid, 75 ppm sodium azide (Sigma), 0.1% (vol/vol) Tween 80, 30 ${\mu}g/ml$ of Vancomycin (Sigma), 5${\mu}g/ml$ of Novobiocin (Sigma), 0.5${\mu}g/ml$ of cysteine HCI, and 1.5% Agar (Difco). All of the eighty six isolates obtained from some foodstuffs were identified as members of the genus Leuconostoc. Comparative counts with the MRS, PES, LUSM, and NLS medium indicated that the recovery percent was lower than other selective media. Therefore, this result suggested that NLS medium was suitable for the isolation of leuconostocs, but not for counting or enumerating.

• Journal of Korea Water Resources Association
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• v.55 no.4
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• pp.257-266
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• 2022

Inundation damage is increasing every year due to localized heavy rain and an increase of rainfall exceeding the design frequency. Accordingly, the importance of hydraulic structures for flood control and defense is also increasing. The hydraulic structures are designed according to its purpose and performance, and the amount of flood is an important calculation factor. However, in Korea, design rainfall is used as input data for hydrological analysis for the design of hydraulic structures due to the lack of sufficient data and the lack of reliability of observation data. Accurate probability rainfall and its temporal distribution are important factors to estimate the design rainfall. In practice, the regression equation of temporal distribution for the design rainfall is calculated using the cumulative rainfall percentage of Huff's quartile method. In addition, the 6^th order polynomial regression equation which shows high overall accuracy, is uniformly used. In this study, the optimized regression equation of temporal distribution is derived using the variable selection method according to the principle of parsimony in statistical modeling. The derived regression equation of temporal distribution is verified through the significance test. As a result of this study, it is most appropriate to derive the regression equation of temporal distribution using the stepwise selection method, which has the advantages of both forward selection and backward elimination.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.253-255
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• 2004

인간(human)에게 나타나는 다양성(variation)은 인체의 유전체(genome) 안에서 발생된 SNP(Single Nucleotide Polymorphism)에 의해 나타난다고 알려져 있다. 유전체내의 SNP과 다양성에 대한 연관 연구(Associate study)를 할 때에 약 30여 억 개로 추정되는 염기서열(DNA sequence)물 모두 분석한다면 많은 비용과 시간을 필요로 할 것이다. 이런 비용과 시간을 줄이기 위친 적은 수의 대표 SNP(=tagSNP)을 찾는 연구가 현재 진행 중이다. 우리는 LD계수｜D;｜을 block 분할에 이용하여 생물학적인 의미를 부여한 후, 전산적인 최적해를 찾는 접근을 이용했다. 또한, 기존 연구에서는 large-scale data에 대한 처리가 불가능해서 chromosome의 일부분의 데이터에 대해서안 분석이 시도되었다. 더욱 광범위한 분석을 위해서 chromosome 단위의 처리가 필요하다. 우리는 chromosome단위의 SNP data를 한 번에 처리가 가능한 시스템인 MarSel를 구현하였다

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.386-388
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• 1999

본 논문은 이미지 데이터의 효율적인 코딩에 대한 새로운 방법을 나타낸다. 웨이블릿 변환을 기초로 한, 알고리즘은 서브밴드 간의 남아 있는 상관관계를 이용한다. 웨이블릿 계수들에 대한 성공적인 대략값은 계층적인 심볼 스트림을 초래하고, 그것은 PSD(의미있는 자손에 대한 예언)과 함께 매우 높게 압축된다. 코딩 알고리즘은 이미지 컨텐트에 대한 높은 적응성에 의해 그 자체를 구별한다. 초래하는 비트스트림은 그것들의 중요도에 대한 순서에 있어서 모든 이미지 정보를 구성한다. 그러므로 그것은 위험한 디코딩 과정 없이 어떤 지점에서 절단하는 것이 가능하다. 이러한 내장된 비트스트림의 이점은 공간적인 규모성(scalability)과 왜곡율이다. 좀 더 나은 향상은 웨이블릿 패킷으로 알려진 새로운 적응적인 웨이블릿 변환을 사용하여 획득된다. 초기의 기법들과 적합하지 않은 현재의 서브밴드에 대한 관련성있는 통계적인 특성들(특히 상관관계)은 처음으로 분석된다. 그것들에 의존하는, 서브밴드가 분해 유무에 관계없이 분해 결정이 만들어진다. 이러한 결과는 최고의 기본적인 선택이 아니고 최적에 가까운 분해 구조를 초래한다. 본 논문에서 제안한 모델의 가장 주요한 이점은 계산적인 비용의 축소이다.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.213-216
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• 2004

본 연구에서는 복잡한 형상을 가진 음원으로부터 방사하는 음장을 등가음원법 (equivalent source method)을 이용하여 재구성한다. 일반적인 등가음원법의 기본 원리는 진동하는 물체의 표면 또는 내부에 등가음원을 분포시켜서 등가음원의 강도를 계산하는 방법이다. 각 등가음원의 강도는 음원의 경계 조건이나 측정된 음장 음압을 통해서 구할 수가 있으며 사용된 등가음원의 차수, 개수 그리고 위치 등은 고려되어야 할 중요한 변수들이다. 기존의 HELS (Helmholtz equation least square) 방법은 한 곳의 위치에 다양한 차수로 이루어진 등가음원을 사용하여 각 차수의 계수를 구하는 방법으로써 구형에 가까운 음원에 대해서 좋은 결과를 보이나 음장의 결과가 최대 차수의 선택에 따라서 큰 오차를 유발하는 문제점이 있다. 따라서 정규화 기법을 사용하여 음장을 재구성하기 위해 필요한 등가음원의 최적 차수를 구하고, 음원 내부에 최적 차수로 이루어진 등가음원을 여러 개의 점에 위치시켜서 재구성 정확도를 향상시켰다. 정규화된 등가음원법의 타당성 검증을 위하여 표면 일부가 진동하는 구에 대한 수치 해석 및 청소기 모델에 대한 음장 재구성 실험 을 수행하였다.