• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.815-819
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• 1996

In this work, regular rotational gaits of the quadruped crawling robot required to change its moving direction without affecting be its orientation and its static stability margin are studied. The regular rotational gaits provide the quadruped crawling robot with omnidirectional characteristics. However, the ideal foothold region for each of legs of the quadruped crawling robot is assumed for simplicity. Nonetheless, it is expected that the results of this paper will provide the insight for both design of legs of the crawling robot with omnidirectional characteristics as well as its operation of the crawling robot system with specified stability margin.

• 조명전기설비학회논문지
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• 제15권1호
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• pp.13-21
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• 2001

3전극 교류형 면방전 플라즈마 디스플레이의 방전특성을 분석하여 최대 방전전압에서 나타나는 방전의 불안정성은 2차방전에 의한 벽전하의 부분소거가 원임임을 알았다. 이를 이용하여 어드레스 방전과 표시방전의 상호관계를 고려한 동작마진을 새로이 정의하였고 실험을 통하여 이의 타당성을 검증하였다. 고속 어드레싱을 하기 위해서는 어드레스 펄스폭을 줄여야 한다. 그러나 어드레스 펄스폭이 좁아지면 어드레스 펄스의 동작마진이 줄어든다. 반면에 표시방전 유지펄스의 동작마진은 어드레스 펄스폭이 $1[{\mu}s]$ 이상만 되면 어드레스 펄스폭에 무관하다는 것을 알앗다. 시렇ㅁ결과 펄스폭 $1[{\mu}s]$의 고속 어드레스 ADS 구동방식으로 HDTV급 셀구조를 가지는 플라즈마 디스플레이 패널에 8bit 256계조의 화상을 구현 하였고 $560[cd/m^2]$의 휘도를 얻었다.

• Journal of Gastric Cancer
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• 제12권3호
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• pp.187-193
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• 2012

Purpose: The aim of this study is to evaluate the feasibility and safety of cardia preserving proximal gastrectomy, in early gastric cancer of the upper third. Materials and Methods: A total of 10 patients were diagnosed with early gastric cancer of the upper third through endoscopic biopsy. The operation time, length of resection free margin, number of resected lymph nodes and postoperative complications, gastrointestinal symptoms, nutritional status, anastomotic stricture, and recurrence were examined. Results: There were 5 males and 5 females. The mean age was $56.5{\pm}0.5$ years. The mean operation time was $188.5{\pm}0.5$ minutes (laparoscopic operation was 270 minutes). Nine patients were T1 stage (T2 : 1), and N stage was all N0. The mean number of resected lymph nodes was $25.2{\pm}0.5$. The length of proximal resection free margin was $3.1{\pm}0.1$ cm and distal was $3.7{\pm}0.1$ cm. Early complications were surgical site infection (1), bleeding (1), and gastro-esophageal reflux disease (1) (this symptom was improved with medication). Late complications were dyspepsia (3) (this symptom was improved without any treatment), and others were nonspecific results of endoscopy or symptom. Conclusions: Cardia preserving proximal gastrectomy was feasible for early gastric cancer of the upper third. Further evaluation and prospective research will be required.

• 조명전기설비학회논문지
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• 제18권3호
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• pp.149-155
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• 2004

본 논문에서는 상정사고 해석을 통해 결정된 가장 심각한 단일 선로고장에 대하여 부하차단이나 재급전을 하지 않고, 유연송전기기의 운전만으로 안전도를 향상시켜 이를 극복할 수 있는 방법을 제시하였다. 즉, 직렬, 병렬, 직병렬보상기기 등 유연송전기기의 각 종류별로 정적 안전도 여유를 최대화하고 안전도 지수를 최소화하는 방법을 개발하였고, 이를 통하여 각 유연송전기기의 최적 운전점을 결정하는 방법을 개발하였다. 여기서, 정적 안전도 지수는 선로 조류 및 모선 전압에 관한 안전도를 정량화하여 식으로 나타낸 것이다. 안전도 지수가 작아지면 안전도 여유는 커지는데, 본 논문에서는 안전도 지수를 반복계산법으로 최소화하였다. 본 논문에서는 제안한 방법은 IEEE 57모션개통에 적용하여 제안된 방법의 정당성을 수치적으로 입증하였다.

• 항공우주시스템공학회지
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• 제16권1호
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• pp.17-27
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• 2022

실제와 모델간의 다양한 불확실성(uncertainties)에 대한 항공기의 강건성 확보를 위해 비행제어시스템은 일정 수준 이상의 안정성 여유(stability margin) 감항기준을 만족할 수 있도록 설계되어야 한다. 미 국방 규격인 MIL-F-9490D와 감항인증 규격인 MIL-HDBK-516B에는 비행제어시스템이 만족해야 하는 이득여유(gain margin)와 위상여유(phase margin) 기준을 제시하고 있다. 그러나 항공기의 개발 단계별 설계 성숙도를 고려하지 않고 전 개발단계에서 동일한 안정성 여유 기준이 적용되면서, 궁극적으로는 항공기 운용영역이 과도하게 제한되는 문제가 발생한다. 본 논문에서는 조종성과 안정성 여유의 관계를 제시하고 개발 단계와 입증 방법에 따라 안정성 여유 기준을 재정립하는 방안을 제시한다. 연구의 결과는 현재 개발되고 있는 항공기뿐만 아니라 향후에 전개될 무인 비행체 개발 시에 적용하여 보다 유연하고 효과적인 방법으로 안정성 여유 기준을 입증하는데 기여하리라 판단한다.

• 한국관광식음료학회지:관광식음료경영연구
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• 제16권2호
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• pp.17-31
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• 2005

Recently, hotel industry has realized the importance of food and beverage sales for the profit maximization, and the focuses on restaurant management has been growing. Accordingly, menu management in the F/B department is one of the most key factors determining the success or failure of business. Therefore, in this study, entree menu items of french restaurant in the deluxe hotel was analysed with presently theorized model of menu analysis, classified into four menu items. Also it was analyzed how those classified menu items influence on sales, number of sold, food cost percentage, contribution margin And, proper ways was presented to make restaurant managers and menu planner in order to increase food operation sales through proper modifications and methods on various menu analysis matrix. In Pavesic's menu analysis method, all of menu items have impact on the sales, number of sold, contribution margin and Primes, Sleepers do so on the food cost. The finding of this study was that Pavesic's menu analysis is superior to menu analysis in terms of the sales, number of sold, food cost percentage, contribution margin. Therefore, Pavesic's menu analysis is useful and efficient method in order to conduct menu engineering.

• 한국안전학회지
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• 제30권5호
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• pp.131-137
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• 2015

For the evaluation of safety margin of a nuclear power plant using a conservative methodology, the influence of applied assumptions such as initial conditions and boundary conditions needs to be assessed deliberately. Usually, a combination of the most conservative initial conditions is determined, and the safety margin for the transient is evaluated through the analysis for this conservative conditions. In existing conservative methodologies, a most-conservative condition is searched through the analyses for the maximum, minimum, and nominal values of the major parameters. In the present study, we investigates a new approach which can be applied to choose a most-conservative initial condition effectively when a best-estimate computer code and a conservative evaluation methodology are utilized for the evaluation of safety margin of transients. By constituting the band of various initial conditions using the random sampling of input parameters, the sensitivity study for various parameters are performed systematically. A method of sampling the value of control or operation parameters for a certain range is adopted by use of MOSAIQUE program, which enables to minimize the efforts for achieving the steady-state for various different conditions. A representative control parameter is identified, which governs the reactor coolant flow rate, pressurizer pressure, pressurizer level, and steam generator level, respectively. It is shown that an appropriate distribution of input parameter is obtained by adjusting the range and distribution of the control parameter.

• 한국관광식음료학회:학술대회논문집
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• 한국관광식음료학회 2005년도 학술논문발표집
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• pp.80-91
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• 2005

Recently, hotel industry has realized the importance of food and beverage sales for the profit maximization, and the focuses on restaurant management has been growing. Accordingly, menu management in the F/B department is one of the most key factors determining the success or failure of business. Therefore, in this study, entree menu items of french restaurant in the deluxe hotel was analysed with presently theorized model of menu analysis, classified into four menu items. Also it was analyzed how those classified menu items influence on sales, number of sold, food cost percentage, contribution margin And, proper ways was presented to make restaurant managers and menu planner in order to increase food operation sales through proper modifications and methods on various menu analysis matrix. In Pavesic's menu analysis method, all of menu items have impact on the sales, number of sold, contribution margin and Primes, Sleepers do so on the food cost. The finding of this study was that Pavesic's menu analysis is superior to menu analysis in terms of the sales, number of sold, food cost percentage, contribution margin. Therefore, Pavesic's menu analysis is useful and efficient method in order to conduct menu engineering.

• 대한기계학회논문집B
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• 제28권11호
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• pp.1384-1389
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• 2004

As operating time of heat exchangers progresses, fouling generated by water-borne deposits and the number of plugged tubes increase and thermal performance decreases. Both fouling and tube plugging are known to interfere with normal flow characteristics and to reduce thermal efficiencies of heat exchangers. The heat exchangers of domestic nuclear power plants have been analyzed in terms of the heat flux and heat transfer coefficient at test conditions as a means of heat exchanger management. Except for the fouling level generated in operation of heat exchangers, also, all of the tubes of heat exchangers have been replaced when the number of plugged tubes exceeds the plugging criteria based on design performance sheet. This paper describes the plugging margin evaluation mettled reflected the fouling of shell-and-tube heat exchangers, which can evaluate the thermal performance for heat exchangers, estimate the future fouling variations, and reflect the current fouling level. To identify the effectiveness of the developed method, the fouling and plugging margin evaluations were performed for a component cooling heat exchanger in a nuclear power plant.

• 유통과학연구
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• 제17권12호
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• pp.95-103
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• 2019

Purpose : Promoting startups has increased in importance in labor market policies since the economic crisis. In Korea, the Ministry of SMEs and Startups is also seeking to revitalize youth startups and traditional markets by moving young stores into idle spaces in traditional markets through 'Project to Support the Activation of Youth Mall'. Research into startups in traditional markets is very limited. Therefore, this study looks at the differences between the management performance of young merchants and senior merchants, and looks at the impact of the business period. Research design, data and methodology : It was divided into youth startup and senior startup based on the age of 40 and startup and nonstartup. Based on these criteria, the company intends to compare and analyze sales and margin rates by setting the sales and margin rates with the management performance of the startup and senior startups. In particular, to look at the feasibility of government funded projects for young merchants, the company will look at the changes in sales and margin rates of young merchants and senior merchants over the period of operation. In this study, the analysis was based on the raw data of the Statistics of traditional market in 2017, and the ANCOVA was used. Results : First of all, the sales volume of stores operated by young merchants, was higher than those operated by senior merchants. Next, the margin ratio does not differ from that of stores that are for young people and those. These findings suggest that the profit structure of stores in traditional markets is similar between young merchants and senior merchants. Third, if you look at the performance of new startups based on one year of business period in more detail, it turns out that young startups have improved in sales and margin rates since startups, while senior startups have no difference. Conclusions : While it means that management performance can be improved through support for young startups, it suggests that there is a limit to supporting senior startups. Therefore, this research indicates that the government support projects centered on youth can contribute to the revitalization of traditional markets.