• Journal of Power Electronics
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• 제10권2호
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• pp.155-164
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• 2010

This paper presents a voltage control algorithm for a hybrid multilevel inverter based on a staged-perception of the inverter voltage vector diagram. The algorithm is applied to control a three-stage eighteen-level hybrid inverter, which has been designed with a maximum number of symmetrical levels. The inverter has a two-level main stage built using a conventional six-switch inverter and medium- and low- voltage three-level stages constructed using cascaded H-bridge cells. The distinctive feature of the proposed algorithm is its ability to avoid the undesirable high switching frequency for high- and medium- voltage stages despite the fact that the inverter's dc sources voltages are selected to maximize the number of levels by state redundancy elimination. The high- and medium- voltage stages switching algorithms have been developed to assure fundamental switching frequency operation of the high voltage stage and not more than few times this frequency for the medium voltage stage. The low voltage stage is controlled using a SVPWM to achieve the reference voltage vector exactly and to set the order of the dominant harmonics. The inverter has been constructed and the control algorithm has been implemented. Test results show that the proposed algorithm achieves the desired features and all of the major hypotheses have been verified.

• 보건의료산업학회지
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• 제13권2호
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• pp.27-38
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• 2019

Objectives: The purpose of this study was to investigate the relationship between medical service quality, emotional attachment, customer satisfaction, and customer behavioral intention of small and medium hospitals. Methods: 228 patients who have used small and medium hospitals' medical services were selected. The analysis methods used were confirmatory factor analysis, validation of discrimination, path analysis, and bootstrapping using SPSS 23 and AMOS 23. Results: As a result of the hypothesis test, reliability, responsiveness, and assurance were found to have a positive (+) influence on emotional attachment and customer satisfaction, while empathy had a positive (+) influence on emotional attachment only. Emotional attachment had a positive (+) influence on customer satisfaction and behavioral intention, and customer satisfaction had a positive (+) influence on behavioral intention. Conclusions: Medical service providers in small and medium hospitals should recognize that increasing customer satisfaction based on emotional attachment is a pathway to customer acquisition and, ultimately, a way to promote effective management.

• 한국산업정보학회논문지
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• 제15권5호
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• pp.273-286
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• 2010

이 연구는 중소 SI업체들이 IT프로젝트를 수행하는데 있어 어떤 공통적인 특성을 보여주는가를 알아보기 위해 진행되었다. 이 연구에서는 2006년부터 2009년까지 중소 제조업체를 대상으로 수행된 194개의 IT프로젝트에 대한 388건의 감리보고서를 기초자료로 사용했다. 연구 결과 프로젝트 관리 분야에서는 일정관리가 가장 취약한(문제가 있거나 또는 관리가 잘안 되는) 것으로 드러났으며, 개발 및 구현 분야에서는 시험 계획과 활동이 가장 취약했으며, 운영 빛 유지보수 분야에서는 사용자/운영자판 위한 매뉴얼 작성이 가장 취약한 것으로 드러났다. 결국 이들 세 가지 취약한 항목들은 중소 SI업체들이 IT프로젝트를 수행하는데 있어서의 공통적인 특성이라고 할 수 있다.

• 산업경영시스템학회지
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• 제46권2호
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• pp.143-151
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• 2023

Expanding exports of small and medium-sized companies is crucial for the continuous growth of the Korean economy. Therefore, the government operates various support systems to enhance the export capabilities of these companies. This study aims to analyze the impact of the Korean government's flagship export support system, known as the export initiation support system, on the performance of participating domestic companies. A fixed effect model using panel data was applied to examine the characteristics of 11,099 companies that participated in the export initiation support system from 2016 to 2019. The analysis revealed that the number of exporting countries, employees, and previous export volume had a significant impact on the export amount of participating companies. However, contrary to expectations, the number of overseas marketing participation and the GCL (global competence level) test did not show a significant impact. This study is significant as it provides implications for the development of support projects tailored to the specific needs of small and medium-sized companies, with the goal of improving the export support system.

• 유통과학연구
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• 제22권4호
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• pp.37-46
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• 2024

Purpose: Social media influencers (SMIs) have become significant sources of information influencing their followers' purchase intentions; few studies have been published on the effect of the number of followers and package tour prices on followers' purchase intention within the Vietnam travel industry utilizing naïve theories. This study examined the relationship between the number of followers and purchase intention and tested the moderating role of package tour price. Research Design, data and methodology: A 2 (number of followers: high vs. medium) × 2 (package tour price: high vs. low) between-subjects factorial design was used. 395 Vietnamese students (114 men, 281 women; M_age = 19.99, SD_age = 1.25) from Thuongmai University participated in the study. ANOVA and PROCESS MARCO were used to test hypotheses. Results: Findings indicate that participants show a higher purchase intention for SMIs with a higher number of followers than those with a medium one. When the package tour price is high, participants with a medium number of followers show a greater purchase intention than those with a high one. Conclusion: This recommendsthat tourism managers collaborate with SMIs with a high number of followers when the package tour price is low and with SMIs with medium ones when the package tour price is high.

• 산업식품공학
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• 제14권2호
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• pp.106-111
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• 2010

본 연구는 일정한 실험조건 하에서 골심지 시료에 따른 골 성형 실험을 행하여 골심지에 의한 하이로골의 발생과 골판지상자의 압축강도의 관계에 대하여 조사하였다. 골판지의 골 높이가 낮은 골(low corrugation)의 비율이 많은 골심지 그레이드는 장력 변동의 저항에도 약하며 골심지의 이탈력에 의한 강탈(stealing)이 일어나기 쉽고, 결과적으로 낮은 골 비율이 높아졌으며, 골심지 두께 편차가 큰 골심지는 골 성형 시에 슬립현상을 발생하기 쉽기 때문에 불규칙한 골을 연속 형성하는 경향이 있었다. 또한 골심지의 그레이드에 따른 하이로골 분포비율의 실험결과 일반적 경향으로는 그레이드가 높은 골심지 일수록 낮은 골비율이 적었다. 골 성형된 골판지 시트의 두께의 경우는 원지 평량과의 상관성은 적고 골심지 두께와 상관하며 y=3.9732x+4.2712, $R^{2}=0.8142$), 골심지의 밀도에 역상관한다((y=-3.1213x+6.8736, $R^{2}=0.9919$). 하이로골 중에서 낮은 골 분포를 크게 나타낸 골심지 재료의 골판지로 만든 골판지상자의 압축강도가 현저히 낮고 골심지 시료의 그레이드에 따라 13%의 차이가 있었으며 압축강도의 편차도 골심지의 시료에 따라 21%로 크며, 골심지 골은 원지의 두께 및 밀도 등 물리적 특성치의 변동과 관계한다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.347-351
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• 2004

The cryogenic test facility is developed for test of deep groove ball bearings, floating ring seals, materials (steel & copper) for High Pressure Turbopump of liquid rocket engine (LRE). The cryogenic bearing test is performed to evaluate the flow rate of cooling water and the load-carrying capacity of bearings. The cryogenic seal test is performed to evaluate the determination of magnitude of leakages through the seal, a time variation of this magnitude. The test of the materials Pair is performed to evaluate its fitness for operation in the liquid oxygen medium.

• 한국치위생학회지
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• 제15권5호
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• pp.841-847
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• 2015

Objectives: The purpose of the study was to investigate the satisfaction with instruction medium according to learner attitude and lecture mode in the dental hygiene students. Methods: A web-based self-reported questionnaire was complected by 155 dental hygiene students in Cheonan from May 26 to June 5, 2015. The questionnaire consisted of general characteristics of the subjects, school adaptation, interest to learn, effort to learn, faculty centered lecture, learner centered lecture, self-directed learning, motivation to learn, characteristics of each subject, and satisfaction with lecture mode. The study was approved by institutional review board (IRB) by Baekseok University. Chi-square test and multivariate logistic regression were used to evaluate the satisfaction to medium of instruction according to explanation factors. Results: The lecture mode, opportunity and motivation to learn, interest to learn and effort to learn were the significant factors to satisfaction with instruction medium. In multivariate logistic regression model, the adjusted odds ratio was 6.28 for the opportunity to learn and 4.87 for the interesting to learn. Conclusions: The satisfaction with instruction medium is the most important factor that decides the lecture mode and learner attitude including opportunity to learn and concern to learn.

• 한국식품영양과학회지
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• 제26권5호
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• pp.872-877
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• 1997

Soybean curd whey(SCW) containing plenty of nutrients is the discarded by-product in soybean curd processing. To test the potential utilization of SCW as a medium for the cultivation of Lactobacilus acidophilus, the chemical composition of SCW, as well as the growth, acid production, acid-tolerance, and bile-tolerance of L. acidophilus in SCW-based media were investigated. Sucrose and stachyose, the main free sugars of SCW, were 0.42% and 0.41%, respectively. SCW contained 36.1mg/L of total free amino acids. L. acidophilus KFRI 150 showed lower cell growth and acid production in SCW than those in MRS broth. In optimized SCW-based medium supplemented with 1.0% glucose, 0.5% yeast extract, and 0.2% $K_{2}HPO_{4}$, the growth and acid production of L. acidophilus KFRI 150 increased by twice against those in SCW. In optimized SCW-based medium, the viable counts of four L. acidophilus strains were mostly at the level of $10^{9}$/ml, which is similar to those in MRS broth. Each acid-tolerance and biletolerance of four L. acidophilus strains cultured in optimized SCW-based medium and MRS broth showed no dist-inguishable difference.

• 한국가축번식학회지
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• 제13권3호
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• pp.134-140
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• 1989

Studies were conducted to seek reasonable methods of rapid freezing of mouse embryos using liquid nitrogen. The effects of the cryoprotectants concentration and the substitution of raffinose to sucrose in freezing and dilution medium on mouse embryo survival rates were determined using the FDA-test. The summarized results are as follows : 1. When 0.3M of sucrose was added into the freezing and dilution medium, FDA scores of embryos were 1.48(1.5M), 3.81(3.0M) and 4.10(4.5M). Higher FDA scores of embryos were obtained in 3.0M and 4.5M glycerol concentrations (P<0.05). 2. With the addition of 0.3M raffinose to the freezing and dilution medium, FDA scores of embryos did not significantly differ between glycerol levels ; 3.97(1.5M), 4.11(3.0M) and 3.54(4.5M). Higher scores of embryos existed in 3.0M glycerol concentration. 3. Concentration of sucrose or raffinose in freezing and dilution medium affected FDA scores of embryos. When sucrose concerations of 0.3, 0.5 and 1.0M were added to the freezing medium, FDA scores of embryos were 3.12, 2.38 and 0, respectively. However, when the same concentrations of raffinose were added to freezing medium, the FDA scores were 4.21, 2.91 and 0. In both cases, better FDA scores of embryos were attained in 0.3M of sucrose or raffinose (P<0.01).