• Proceedings of the Korea Society for Simulation Conference
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• 1996.05a
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• pp.1-3
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• 1996

시뮬레이션 기법을 이용한 시스템의 분석에 있어서 실험의 자동화는 현재 많은 연구와 개발이 진행 중인 분야이다. 컴퓨터와 정보통신 시스템에 대한 시뮬레이션의 예를 들어 보면, 수많은 모델을 대한 시뮬레이션을 수행할 경우 자동화된 실험의 제어가 요구되고 있다. 시뮬레이션 수행회수, 수행길이, 데이터 수집방법 등과 관련하여 시뮬레이션 실험방법이 자동화가 되지 않으면, 시뮬레이션 실험에 필요한 시간과 인적 자원이 상당히 커지게 되며 출력데이터에 대한 분석에 있어서도 어려움이 따르게 된다. 시뮬레이션 실험방법을 자동화하면서 효율적인 시뮬레이션 출력분석을 위해서는 시뮬레이션을 수행하는 경우에 항상 발생하는 초기편의 (initial bias)를 제거하는 문제가 선결되어야 한다. 시뮬레이션 출력분석에 사용되는 데이터들이 초기편의를 반영하지 않는 안정상태에서 수집된 것이어야만 실제 시스템에 대한 올바른 해석이 가능하다. 실제로 시뮬레이션 출력분석과 관련하여 가장 중요하면서도 어려운 문제는 시뮬레이션의 출력데이터가 이루는 추계적 과정 (stochastic process)의 안정상태 평균과 이 평균에 대한 신뢰구간(confidence interval: c. i.)을 구하는 것이다. 한 신뢰구간에 포함되어 있는 정보는 의사결정자에게 얼마나 정확하게 평균을 추정할 구 있는지 알려 준다. 그러나, 신뢰구간을 구성하는 일은 하나의 시뮬레이션으로부터 얻어진 출력데이터가 일반적으로 비정체상태(nonstationary)이고 자동상관(autocorrelated)되어 있기 때문에, 전통적인 통계적인 기법을 직접적으로 이용할 수 없다. 이러한 문제를 해결하기 위해 시뮬레이션 출력데이터 분석기법이 사용된다.본 논문에서는 초기편의를 제거하기 위해서 필요한 출력데이터의 제거시점을 찾는 새로운 기법으로, 유클리드 거리(Euclidean distance: ED)를 이용한 방법과 현재 패턴 분류(pattern classification) 문제에 널리 사용 중인 역전파 신경망(backpropagation neural networks: BNN) 알고리듬을 이용하는 방법을 제시한다. 이 기법들은 대다수의 기존의 기법과는 달리 시험수행(pilot run)이 필요 없으며, 시뮬레이션의 단일수행(single run) 중에 제거시점을 결정할 수 있다. 제거시점과 관련된 기존 연구는 다음과 같다. 콘웨이방법은 현재의 데이터가 이후 데이터의 최대값이나 최소값이 아니면 이 데이터를 제거시점으로 결정하는데, 알고기듬 구조상 온라인으로 제거시점 결정이 불가능하다. 콘웨이방법이 알고리듬의 성격상 온라인이 불가능한 반면, 수정콘웨이방법 (Modified Conway Rule: MCR)은 현재의 데이터가 이전 데이터와 비교했을 때 최대값이나 최소값이 아닌 경우 현재의 데이터를 제거시점으로 결정하기 때문에 온라인이 가능하다. 평균교차방법(Crossings-of-the-Mean Rule: CMR)은 누적평균을 이용하면서 이 평균을 중심으로 관측치가 위에서 아래로, 또는 아래서 위로 교차하는 회수로 결정한다. 이 기법을 사용하려면 교차회수를 결정해야 하는데, 일반적으로 결정된 교차회수가 시스템에 상관없이 일반적으로 적용가능하지 않다는 문제점이 있다. 누적평균방법(Cumulative-Mean Rule: CMR2)은 여러 번의 시험수행을 통해서 얻어진 출력데이터에 대한 총누적평균(grand cumulative mean)을 그래프로 그린 다음, 안정상태인 점을 육안으로 결정한다. 이 방법은 여러 번의 시뮬레이션을 수행에서 얻어진 데이터들의 평균들에 대한 누적평균을 사용하기 매문에 온라인 제거시점 결정이 불가능하며, 작업자가 그래프를 보고 임의로 결정해야 하는 단점이 있다. Welch방법(Welch's Method: WM)은 브라운 브리지(Brownian bridge) 통계량()을 사용하는데, n이 무한에 가까워질 때, 이 브라운 브리지 분포(Brownian bridge distribution)에 수렴하는 성질을 이용한다. 시뮬레이션 출력데이터를 가지고 배치를 구성한 후 하나의 배치를 표본으로 사용한다. 이 기법은 알고리듬이 복잡하고, 값을 추정해야 하는 단점이 있다. Law-Kelton방법(Law-Kelton's Method: LKM)은 회귀 (regression)이론에 기초하는데, 시뮬레이션이 종료된 후 누적평균데이터에 대해서 회귀직선을 적합(fitting)시킨다. 회귀직선의 기울기가 0이라는 귀무가설이 채택되면 그 시점을 제거시점으로 결정한다. 일단 시뮬레이션이 종료된 다음, 데이터가 모아진 순서의 반대 순서로 데이터를 이용하기 때문에 온라인이 불가능하다. Welch절차(Welch's Procedure: WP)는 5회이상의 시뮬레이션수행을 통해 수집한 데이터의 이동평균을 이용해서 시각적으로 제거시점을 결정해야 하며, 반복제거방법을 사용해야 하기 때문에 온라인 제거시점의 결정이 불가능하다. 또한, 한번에 이동할 데이터의 크기(window size)를 결정해야 한다. 지금까지 알아 본 것처럼, 기존의 방법들은 시뮬레이션의 단일 수행 중의 온라인 제거시점 결정의 관점에서는 미약한 면이 있다. 또한, 현재의 시뮬레이션 상용소프트웨어는 작업자로 하여금 제거시점을 임의로 결정하도록 하기 때문에, 실험중인 시스템에 대해서 정확하고도 정량적으로 제거시점을 결정할 수 없게 되어 있다. 사용자가 임의로 제거시점을 결정하게 되면, 초기편의 문제를 효과적으로 해결하기 어려울 뿐만 아니라, 필요 이상으로 너무 많은 양을 제거하거나 초기편의를 해결하지 못할 만큼 너무 적은 양을 제거할 가능성이 커지게 된다. 또한, 기존의 방법들의 대부분은 제거시점을 찾기 위해서 시험수행이 필요하다. 즉, 안정상태 시점만을 찾기 위한 시뮬레이션 수행이 필요하며, 이렇게 사용된 시뮬레이션은 출력분석에 사용되지 않기 때문에 시간적인 손실이 크게 된다.

• Journal of Preventive Medicine and Public Health
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• v.29 no.4 s.55
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• pp.801-814
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• 1996

Background: Korean people could abuse healthy foods as well as medications, which might cause serious side effects. The aim of this study was elucidating liver dysfunction due to the self-medications of hepatotonics, healthy foods and herb medications by nested case-control study. Methods: Study subjects were drawn from male members of Seoul Cohort Study who were recruited by self-administered structured questionnaire survey through mailing to the healthy men between the age of 40 and 59 years through the program of biennial health check-up offered by Korea Medical Insurance Corporation(KMIC). The liver dysfunction was defined as the level of serum AST and ALT above 40 IU/L and increased in more than one hunderd per-cent during the 2 year follow-up period. To estimate the odds ratio between self-medication and liver dysfunction after controlling for potential confounders, logistic regression was performed. Results: During the follow-up period, 30 members were identified to fit into case criteria and 2,625 members were selected as control. In logistic regression analyses, history of healthy foods intake, age under 45 years, obesity, and habit of regular exercise were significantly associated with liver dysfunction. The following factors exhibited no statistical significance: intake of hepatotonics, of herb medicine; history of disease in family, of operation, and of radiologic examination; smoking habits and drinking amounts. Conclusion: The significant association between the intake of healthy foods and the liver dysfunction illustrates that chronically optional overuse of healthy foods might bring to hazards to health. As the increasing trend of the size of purchasing healthy foods in Korea, pharmacoepidemiologic studies evaluating the safety and efficacy of the widely used healthy foods should be performed in the near future.

• 한국노년학
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• v.31 no.3
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• pp.831-848
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• 2011

The purpose of this study is to analyse the family caregivers' stress pathways by types of long term care services for the elderly, and then to discuss the findings of analysis. For this research, primary caregivers that provide care the elderly requiring long term care services sanctioned by National Health Insurance Corporation were drawn and surveyed. Among collected data, data for 258 primary caregivers by type of long term care services were used for this study. The results of this study can be summarized as follows. First, on average, the elders that utilize care service in institutions for the elderly were higher proportion of women, older, higher rate of bereavement, more children than the elders that utilize in-home care service, but some cases were vice-versa. Second, the elders that utilize care service in institutions more ADL dependency, higher proportion of severe dementia or severe stroke, higher care rank by National Health Insurance Corporation than the elders that utilize in-home care service on average. Third, primary caregivers with elders that utilize in-home care service were higher proportion of women, older, lower education level, higher rate of spouse and daughter-in-law in relationship with care recipient, less health, lower income than primary caregivers with elders that utilize care service in institutions. Fourth, subjective indicators representing caregivers' reactions to caregiving for the elderly significantly impact on caregivers' stress(ie, depression), and pathway of caregivers' stress are differentiated by type of long term care services. Fifth, stressors that have direct impacts on depression as caregiving family are differentiated by type of long term care services. Therefore, policies or programs to reduce negative mental health or stress of caregivig families should be designed differently by reflecting pathway of various stressors and stress by use types of long term care services for the elderly.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.4
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• pp.119-133
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• 2014

This study examines the effects of social network support types on the subjective satisfaction of life for elderly people focused on the impact of voluntary and present oriented social network type represented by hobby club vs. non voluntary and past oriented social network type for example alumni association in Korean society respectively. According to the advanced studies figured out by preceding researchers, most of social networks had a good and positive effects on the elderly people's subjective satisfaction of life. However, this study tried to classify the social networks by type such as starting time to make relationship among members and voluntary or non voluntary for participation to the networks. As a result of this study, voluntary and present oriented social network represented by hobby club has a very positive relationship with Korean elderly people's subjective satisfaction of life while non voluntary and past oriented social network as alumni association has no relationship with elderly people's subjective satisfaction of life. Therefore, government policies and budget should be concentrated on encouraging or supporting voluntary and present oriented social networks such as hobby club, voluntary agency etc. rather than non voluntary and past oriented social networks so as to maximize the effect for increasing Korean elderly people's subjective satisfaction of life.

• The Journal of the Korea Contents Association
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• v.12 no.10
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• pp.169-177
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• 2012

Due to the influences of global financial crisis, countries are putting their efforts on the enhancement of appropriateness and transparency of director compensation. In several countries including Germany, the United States, the United Kingdom, France, and Italy, listed companies and financial institutions in certain levels make public announcement for compensations of individual directors, not the averages. Recently, even Asian countries including China, Hong Kong, and Singapore are introducing individual director compensation public announcement policies. On the other hand, in cases of companies, which must submit annual reports, under current Korean capital market laws and enforcement ordinances, they are obligated to mention 'total wage paid to all executives in that business year' on the annual report, but does not have to mention individual wages of each executive. About this, at the 17th national assembly, revised bill for the Securities and Exchange Act for companies to mention wages of each executive. The financial world is opposing to open individual director compensation to the public as they concern about the shrinking of outstanding human resources recruitment, breach of corporate confidence, privacy invasion, deterioration of labor-management relations, and downfall of the executive's management will as director compensation will be standardized downward; however, if public opening of individual director compensation is forced, domestic companies will prepare more objective and rational standards when they calculate director compensations, and moreover, it will prevent arbitrary intervention of dominant shareholders. Therefore, to clearly and efficiently control director compensation, we need regulations for obligating public opening of individual director compensation.

• The korean journal of orthodontics
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• v.37 no.4
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• pp.272-282
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• 2007

The purposes of this study were to evaluate the nasolabial angle changes between closed lip position at centric occlusion and relaxed lip position at which the bite is open so that the lips do not touch and to elucidate the significance of the relaxed lip position for dentofacial diagnosis. Methods: The subjects consisted of 60 (35 Males, 25 Females) skeletal Class III malocclusion adult patients (mean age 23.3 years) with anterior crossbite. Results: In Class III malocclusion adult patients, there were significant differences in the nasolabial angle changes between closed lip position and relaxed lip position. Using the cluster analysis, the subjects were divided into three groups according to the pattern of nasolabial angle change: Group 1 (N = 27, 45%, $-8\;{\sim}\;1$), Group 2 (N = 30, 50%, $2^{\circ}\;{\sim}\;17$), and Group 3 (N = 3, 5%, over 18). Conclusion: The results showed that the pattern of the nasolabial angle change between closed lip position and relaxed lip position varies in skeletal Class III malocclusion patients. Thus, relaxed lip position should be taken into account when diagnostic records are obtained and analyzed to accurately to evaluate the facial soft tissues and predict facial esthetics after surgical-orthodontic treatment.

• The korean journal of orthodontics
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• v.35 no.3 s.110
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• pp.163-173
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• 2005

The purpose of this study was to compare the asymmetric degree between maxillofacial hard and soft tissues in individuals with facial asymmetry. Computerized tomographies (CT) of 34 adults (17 male, 17 female) who had facial asymmetry were taken. The CT images were transmitted to personal computers and then reconstructed into three-dimensional (3D) images through the use of computer software. In order to evaluate the degree of facial asymmetry, 6 measurements were constructed as the hard tissue measurements while 6 counterpart measurements were taken as the soft tissue measurements. The means and standard deviations were obtained for each measurement using 3D measure, then t-test was used to investigate the differences between each hard tissue measurement and the corresponding soft tissue measurement All measurements used in the present study showed statistically significant differences between the hard and soft tissues. The degree of soft tissue asymmetry was smaller than that of corresponding hard tissue asymmetry in case of chin deviation, frontal ramal inclination difference, and frontal corpus inclination difference. On the other hand, the degree of soft tissue asymmetry was greater than that of underlying hard tissue asymmetry in the measurement of lip canting and lip cheilion height difference The present study suggests that asymmetric differences of hard and soft tissue is observed nu facial asymmetric subjects and thus soft tissue analysis is needed in addition to hard tissue analysis when making an evaluation of facial asymmetry.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.481-491
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• 2009

This study was conducted to observe some characteristics of aneuploid trees obtained from the crosses between diploid and triploid in the first experiment. The results showed that the difference among the percentage of aneuploid's pollen grain germination was large, and all of them were lower than that of diploid 'Hongro' (82.4%). The average weight and size of each aneuploid's fruit was far lighter and smaller than that of diploid 'Hongro'. According to the width and length, all of the fruits shape was flat or short-globose conical shape except for JF3942. Almost all the aneuploid had higher sugar content than 'Hongro', nearly half of aneuploid fruits were firmer than that of diploid 'Hongro'. As for the acid contents of aneuploid fruits, the results were greatly different from those of previous studies on diploid apples, in present study the citric acid and tartaric acid contents were more than the malic acid which are dominant acid in most cultivars of apples. Both the length and width of aneuploid tree were shorter than that of diploid 'Hongro'. Most aneuploid trees' height was longer than width, but there were 4 exceptions. The size of leaves was smaller than that of diploid 'Hongro' according to the length and width of leaves measured. In all, aneuploid's vegetative growth is not as vigorous as diploid.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.3
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• pp.85-97
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• 2015

This study examined the effects of outside directors and CEO duality on acquisition strategies and performance of Korean firms in high-technology industry. Based on the resource dependence theory, we focused on the service and resource-dependence roles from board of directors in the process of decision-making of acquisition strategies. In addition, CEO opportunism behavior rises when CEO serves as chairperson of board and induces the negative effects on acquisition performance. Specifically, we investigated the interaction effects between outside directors ratio and CEO duality. For the period of 2004 to 2012, 246 acquisitions of Korean firms in high-technology industry were analyzed to test our intended hypotheses. Our results indicate that there exist positive relationship between outside director ratio and acquisition performance for Korean high-technology firms. Negative associations prevail between CEO duality and performance consequences of acquisitions. While outside director ratio has a positive effect on acquisition performance when there is a presence of CEO duality, negative effect prevail for outside director ratio on acquisition performance in the absence of CEO duality position to hold our interaction hypothesis. The favor of dual structure can be explained with implications referring to unity of command and strong leadership driven from CEO duality that enhances the resource dependence roles of board of directors in the context of high-technology industry acquisition behaviors rendered by Korean firms.

• Archives of design research
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• v.17 no.2
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• pp.43-54
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• 2004

The appreciation of cultural properties related with what the aspects of society was is mandatory to understand our culture correctly. To make over all cultural properties to our descendants without breakage or damage is our natural duty and national obligation. On the contrary, inhabitants in the preserved area should be restricted and controlled by the cultural property law. The conflict between the inhabitants in the preserved area and the government raises economical problems and damages all the time. Especially it is time to discuss to mediate between them and solve the problems. This feasible study is a proposal to settle them up through renovating abolished school in the preserve area to the museum and a case to preserve the cultual properties as well as habitant's assets in that area.