• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1605-1606
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• 2015

전기철도차량은 매 순간마다 이동하는 대용량 단상부하로, 전력계통 측면에서 부하의 특성이나, 계통구성의 형태 및 제반현상이 일반 3상 전력계통과 상이한 특성을 지닌다. 이와 같이 3상 전력계통으로 부터 단상 교류로 변환하여 전기차를 운행하는 경우에는 3상 전원측 PCC(Point of Common Coupling)에 불평형을 일으켜, 역상전류를 발생시킨다. 현재는 이를 최소화하기 위해서 종래부터 사용 되어온 스코트 결선 변압기를 사용하고 있다. 하지만 특성상 두 개의 단상 시스템에 걸리는 부하량 및 역율이 동일하지 않을 경우 여전히 3상 전압불평형이 발생된다. 이에 대한 근본적인 대책으로는 급전시스템 재구성 또는 전력 설비 증설 및 보상장치의 적용을 들 수 있으나, 최근에는 전력전자 기술의 발달로 IGBT(Insulated Gate Bipolar Transistor) 소자를 이용한 BTB(Back To Back) 방식의 컨버터를 활용한 사례가 연구되고 있다. 본 논문에서는 전력계통과 전기철도의 연계 목적으로 3상-단상 BTB 모듈형 멀티레벨 컨버터 (Modular Multi-level Conveter, MMC)를 이용한 전기철도 급전 시스템의 기본구조를 제안하고, Mathworks사의 MATLAB Simulink tool를 이용하여 시뮬레이션을 통해 MMC시스템을 검토하고자 한다.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.2
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• pp.160-165
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• 1998

The Joint curing barns for flue-cured tobacco is a favorite with the tobacco farmers in Korea. However, most of farmer utilizing the joint curing barns indicated many problems such as high temperature and noise in the working room and a dry of cured leaves in the storage room. A structure of Joint curing barns has been modified to meet the needs of tobacco farmers. Compared with the unimproved joint curing barns, the improved one showed that the noise of workshop decreased about 7.7～10.8db, the amount of $CO_2$ decreased 40～50ppm in a working room and 80～100ppm in a machine room. Ammonia gas decreased 0.29mg/㎥ and the temperature of a working room dropped about 2.1～3.5$^{\circ}C$. The amount of air flow in a working room increased 23.2% at a site being 2m away from the entrance and 30.8% at a center. The inner temperature of the improved storage room showed that maximum temperature dropped about 3$^{\circ}C$, minimum temperature was high about 2$^{\circ}C$. The highest relative humidity was low 6%, the lowest one increased high about 10% when compared with the unimproved joint curing barns.

• Journal of the Korean Society of Tobacco Science
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• v.22 no.1
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• pp.45-50
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• 2000

In order to improve the sowing practice, pelleted seeds of tobacco NC 82(Nicotiana tobacco L.) were manufactured in use of binders at the different levels of viscosity, and their physical properties according to pellet size and biological activity in seed germination were investigated while storage time elapsed. Proper range of the binder viscosity for the pellet formation was 20.3-37.2 m.pas. At the high level of viscosity(45.7 m.pas) took longer time to form the pellet and pelleting was not easy. The high binder viscosity and large pellet size revealed higher level in hardness of the pelleted tobacco seeds, which caused the longer splitting time of pellets in water. High level of binder viscosity(37.2 m.pas) in pelleted seeds led to decrease the biological activity of tobacco seed germination by the storage at 4 t over 30 days. But at the level of 20.3m.pas in binder viscosity, the germination of pelleted seeds was little affected by the long storage time to 120 days.

• Journal of Korean Medicine for Obesity Research
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• v.6 no.1
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• pp.51-59
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• 2006

Objectives : This study was designed to evaluate the relationship with abdominal visceral fat area in obese patients identified as phlegm type. Methods : This research were performed in 201 cases, visited Kirin Oriental Hospital from March 2005 to February 2006 for weight loss. We measured body mass index(BMI), abdominal CT, and classified all patients into two groups, normal and obesity group. And then we differentiated patients with phlegm-retention symptom from patients without it through questionnaire made by Korea Institute of Oriental Medicine. Results and Conclusions : Phlegm type was significantly higher than them of no symptom of phlegm in the abdominal visceral areas(P=0.036) and ratio(P=0.007), in obesity group$(BMI{\geq}25)$. On the other hand, there is little difference between abdominal visceral fat areas of phlegm type and no symptom of phlegm in normal group. According to the above results, if obese patients are diagnosed as identification of phlegm type there is good chance of abdominal visceral obesity.

• Journal of Korean Medicine for Obesity Research
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• v.6 no.1
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• pp.61-67
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• 2006

Objectives : The purpose of this study was to determine what is useful index of abdominal visceral fat area among Korean obese adolescents. Methods : 35 obese adolescents who had visited Kirin Oriental Hospital from August 2004 to May 2006 were included in the study. Weight, height, waist and hip circumferences were measured. Abdominal visceral fat areas at L4-5 level were measured by computed tomography. The subjects were divided into two groups, according to sex. In each group, we investigated the correlation among waist circumference, waist/hip ratio, waist/height ratio, obesity degree and abdominal visceral fat area and evaluated that which one of these kinds of indices is the most useful predictor for visceral fat area in Korean obese adolescents. Results : There were significant correlation between waist circumference, waist/hip ratio, waist/height ratio and obesity index in both group. In boys waist/hip ratio had correlation with abdominal visceral fat area and in girls obesity index had significant correlation with abdominal visceral fat area. Conclusions : Our study suggests that waist/hip ratio in boys, obesity degree in girls can be a relatively good parameter for predicting abdominal visceral fat area.

• Journal of Korean Medicine for Obesity Research
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• v.6 no.2
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• pp.75-83
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• 2006

Objectives : This study was performed to identify the effects of high frequency therapy on localized obesity. Methods : This trial was carried out in 12 volunteers. Volunteers were divided into 3 groups; upper arm group (n=4), thigh group (n=4) and abdomen group (n=4) according to local obesity type. Body weight and body fat were measured by Inbody 720 and CT (Computed Tomography) immediately before and following high frequency therapy. Diathermy was performed twice a week for 4 weeks for a total of 8 treatments. Results : In the upper arm group, body weight, body fat mass, fat area by CT scan and circumference were increased after treatment but not significantly (p>0.05). In the thigh group, body weight, body fat mass and circumference were decreased and fat area by CT scan was increased but both not significantly (p>0.05). In the abdomen group, significant differences were not found despite decreases in body weight, body fat mass, visceral fat and subcutaneous fat after diathermy (p>0.05). Conclusions : There was no significant effects of high frequency therapy on localized obesity.

• Journal of the Korean Society of Tobacco Science
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• v.16 no.1
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• pp.69-75
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• 1994

A new flue - cured tobacco variety KF113 was developed by Nicotiana africana method from a cross of NC82 and Coker 347 at the Suwon Experiment Station. It was tested in the 0fficial Variety Test in 1991-1992 and the flue - cured Regional Farm Test in 1992. KFl13 flowers 4 days later than WC82 (standard variety in Korea) and its harvestable leaves are 2 more than those of NC82. The leaf type and shape of KFl13 resembles Coker 347. It has high resistance to bacterial wilt (Pseudomonas solanacearum) and black shank (Phytophthora parasitica var. nicotianae), and is susceptible to tobacco mosaic virus. It should adapt well to the flue - cured production area and can reduce premature flowering under unfavorable weather conditions. Yield of KFl13 is 5% higher than that of NC82, and nearly equal in value per kg compare with NC82. This variety met acceptable standards for chemical and physical characteristics of cured leaf and for smoking taste evaluated by panel members in Korea Ginseng & Tobacco Research Institute.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1516-1529
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• 2016

While global manufacturing is becoming more competitive due to variety of customer demand, increase in production cost and uncertainty in resource availability, the future ability of manufacturing industries depends upon the implementation of Smart Factory. With the convergence of new information and communication technology, Smart Factory enables manufacturers to respond quickly to customer demand and minimize resource usage while maximizing productivity performance. This paper presents the development of a big data analytics platform architecture for Smart Factory. As this platform represents a conceptual software structure needed to implement data-driven decision-making mechanism in shop floors, it enables the creation and use of diagnosis, prediction and optimization models through the use of data analytics and big data. The completion of implementing the platform will help manufacturers: 1) acquire an advanced technology towards manufacturing intelligence, 2) implement a cost-effective analytics environment through the use of standardized data interfaces and open-source solutions, 3) obtain a technical reference for time-efficiently implementing an analytics modeling environment, and 4) eventually improve productivity performance in manufacturing systems. This paper also presents a technical architecture for big data infrastructure, which we are implementing, and a case study to demonstrate energy-predictive analytics in a machine tool system.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.42-42
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• 2015

사행수로에서의 원심력은 비선형적인 압력분포를 야기하여 이차류, 편수위 등과 같은 불규칙하고 복잡한 흐름을 발생시킨다. 일반적으로 이들 흐름은 난류이고 매우 3차원적이며 자유수면과의 상호작용이 중요한 역할을 할 수도 있다. 환경, 유사이동, 지형 변화와 관련된 환경 수리학적 관점에서 사행수로에서의 흐름을 이해하고 설계하기 위해서는 이러한 복잡한 3차원 흐름을 정확하게 계산하는 것이 매우 중요하다. 이 연구에서는 유한차분법에 근거한 3차원 흐름해석 모형을 이용하여 사행수로에서의 난류 흐름을 모의하고자 한다. 지배방정식은 3차원 비정상 RANS(Reynolds averaged Navier-Stokes) 방정식이며, 난류 해석을 위해서 공학적으로 널리 이용되고 있는 난류 모형 중 k-omega 모형을 이용한다. 수치모형은 시간과 공간에 대해서 2차 정확도의 이산화 기법을 적용한다. 자유수면의 변동은 이상(two-phase) VOF (volume of fluid) 기법을 이용하여 계산한다. 수치모형의 적용 대상은 기존 문헌에서 제시되어 있는 키노시타 사인곡선을 이용하여 만든 폭 60cm의 사행수로에서 후르드수 0.23 그리고 레이놀즈수 41,700의 조건에서 발생시킨 난류 흐름이다. 적용한 난류모형들을 이용하여 해석한 결과들을 유속벡터분포와 수위의 항으로 비교분석하여 사행수로에서 발생되는 이차류와 편수위 변화 재현에 대한 수치모형의 적용성을 평가하고 각 난류모형들의 특성을 제시한다.

• Journal of the Korean Society for Railway
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• v.11 no.6
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• pp.588-595
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• 2008

This study is carried out for understanding mode choice behavior of shippers and introducing ideal mode share between rail and truck in Korea. The model type is individual behavioral model and the input data type is stated preference (SP) data. SP data was prepared by design of experiments. The explanatory variables in models are transport time, transport cost and service level. The research result shows that it is more effective to reduce transport cost rather than to implement other strategies. For container, reducing transport cost and transport time and increasing service level simultaneously can strengthen the competitiveness of rail over truck transportation. On the other hand, for bulk freight such as cement and steel, it is better to reduce the transport cost than to do other attributes.