• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.4
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• pp.341-349
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• 2004

A parallel operation of Uninterruptible Power Supply(UPS) systems is used to increase power capacity of the system or to secure higher reliability at critical loads. In the conventional parallel operation, the load-sharing control to maintain the current balance is the most important, since the load-sharing is very sensitive to discord between components of each module, amplitude/phase difference, line impedance, output LC filter, and so on. To solve these problems various control algorithms are researching. However, these methods cannot apply to the different ratings of UPS. In the case, master and slave control algorithm for parallel operation is adequate. However, if the UPS ratings are different, the value of passive filters L, C is different, and it affects the sharing of current. This paper presents general problems of conventional parallel operation systems, and control strategy for parallel operation with different ratings. The validity of the proposed control strategy is investigated through simulation and experiment in the parallel operation system with two 3-phase UPS systems.

• The Journal of the Korea Contents Association
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• v.13 no.4
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• pp.262-272
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• 2013

This study was conducted to investigate the association between breast cancer-related risk factors including socio-demographic characteristics and the lifestyle-related factors and the development of breast cancer. The study was comparative analysis of cancer patients group and control group. 102 breast cancer patients visited in J university hospital and 110 randomly-selected community controls were recruited from October 2011 to June 2012. Eating vegetables, physical activity and stress coping reduce breast cancer risk. Therefore, this study highlights the importance of eating vegetables, physical activity, and stress management in preventing breast cancer.

• Journal of the Korea Society for Simulation
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• v.29 no.2
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• pp.35-47
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• 2020

Immediate and serious attention on CGF(computer generated forces) behavior modeling for defense M&S (modeling & simulation) is required in response to the reduction in the number of troops and development of 4^th industrial technologies. It is crucial for both military person and engineer to understand such technologies. The research aims to provide guidelines for establishment of research direction on CGF behavior modeling. We investigate traditional and/or novel methodologies such as rule-based, agent-based, and learning-based method. Discussions on future direction of applicable area and strategies are followed. We expect that the research plays a key role for understanding CGF behavior modeling.

• The korean journal of orthodontics
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• v.35 no.2 s.109
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• pp.148-152
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• 2005

This case report describes the treatment of an impacted tooth in relation to pediatric mandibular fracture. A 10-rear-old girl presented with au impacted mandibular canine related with a miniplate in the left mandibular body area. An ordinary surgical traction ended in failure. Good occlusion was established by removal of the miniplate. It would be considered important to make an exact diagnosis of the cause and remove the mechanical obstruction instantly for successful orthodontic treatment of an impacted tooth.

• Tuberculosis and Respiratory Diseases
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• v.39 no.2
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• pp.167-171
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• 1992

Background:In the management of patients whose primary chemotherapy has failed, very careful assessment is essential. It is important to find out as accurate a chemotherapy history as possible. Preferably it should contain the drugs which has never used before. The present report concerns the results of retreatment of pulmonary tuberculosis patients treated at National Kongju Tuberculosis Hospital. Method: A retrospective study was made through the regular follow-up of 112 smear positive cases, who were treated by four-drug regimen between July 1985 and June 1990. Four drugs were, namely prothionamide, cycloserine, para-aminosalicylic acid, and streptomycin (kanamycin or tuber-actinomycin). The duration of follow-up was over one year. Results: 1) Out of 112 cases with positive sputum AFB smear, 72 (64%) achieved the negative conversion. 2) Among the 72 patients, 85% achieved negative conversion within 3 months after treatment. 3) When the duration of patient's illness was less than 2 years, 2 to 4 years and more than 5 years, the favourable response to retreatment was 86%, 62% and 54%, respectively. 4) When the number of sensitive drugs was 4,3,2 and 1, the favourable response rate was 74%, 68%, 39% and 0%, respectively. Conclusion: The shorter the duration of patient's illness was, the larger the number of sensitive drugs was. And the larger the number of sensitive drugs was, the better the result of treatment was. Thus it is very crucial to successfully treat newly discovered patients with adequate regimens and proper case-holding.

• Korean Journal of Psychosomatic Medicine
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• v.21 no.2
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• pp.132-139
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• 2013

Objectives: The aims of this study were to know the prevalence of cognitive disorders in patients with thyroid cancer, and identify related variables to them. Methods: Subjects were consisted of fourty-two patients with thyroid cancer, who were admitted for radioiodine ablative therapy at 6-12 months after total thyroidectomy. The data were obtained from interviews about history and assessments of depression and cognitive function(Korean Version of the Montreal Cognitive Assessment, MoCA-K). Results: 1) Among subjects, those with below 22 of total score of the MoCA-K were twenty-one(50.0%). 2) Upon age, education, Pre-radioiodine therapy thyroid stimulating hormone(TSH), there were statistically significant difference between subgroup with above 23 of the total MoCA-K score and those below 22. 3) The total scores of the MoCA-K in subjects had significant correlation with age, education, comorbidity, Pre-radioiodine therapy TSH, total score of the HDRS-17. Conclusions: Cognitive disorders were more prevalent among patients with thyroid cancer before radioiodine therapy. Therefore, further study should be needed to clarify the mechanism for the cognitive disorders in thyroid cancer. Furthermore, physicians should pay attention to the cognitive function and prepare preventative measures for cognitive disorder during management of thyroid cancer.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.4
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• pp.535-539
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• 2000

Ectopic eruption of a tooth into the oral environment occurs commonly whereas ectopic eruption of a tooth into other sites is rare. Those that have been reported include the nasal cavity, chin, mandibular condyles, coronoid processes, orbits and maxillary sinus. The etiologic factors of ectopic eruption are developmental disturbances such as cleft palate and teeth displaced by trauma or cysts, maxillary infection, genetic factors, crowding and exceptionally dense bone. In many cases, however, the etiology cannot be identified. Eruption of the teeth into the maxillary sinus is uncommon, however the identification of such teeth can be important since they have the potential to cause considerable morbidity. The definitive treatment is surgical removal of the teeth. A 7 year-old-boy visited the Department of Pediatric Dentistry, College of Dentistry, Yonsei University for treatment of dental caries. The abnormal erupting paths of the left and right maxillary canines were found during routine panoramic radiographic investigations. A panoramic radiograph taken at 13 years old revealed that two maxillary canines were located into the sinus. The teeth were extracted by the Caldwell-Luc approach.

• The Journal of the Korea Contents Association
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• v.22 no.2
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• pp.794-802
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• 2022

This retrospective study was to investigate the characteristics of unplanned readmission and factors affecting readmission within 30 days of discharge in patients who underwent heart valve surgery through electronic medical records. The participants were 423 unplanned re-hospitalization within 30 days after heart valve surgery at a tertiary hospital in Seoul from January 2018 to August 2019. A total of 48 patients (11.3%) were unplanned readmissions, and the most common causes were atrial fibrillation in 13 cases (27.1%) and pain at the surgical site in 13 cases (27.1%). Other causes were: 10 cases (20.8%) of warfarin inappropriate treatment concentration, 7 cases of general weakness (14.6%), 5 cases of hypotension (10.4%), 4 cases of pericardial effusion (8.3%), 3 cases of surgical wound infection (6.3%), 3 cases of hemorrhage (6.3%), 3 cases of high fever (6.3%), and 1 case of cerebral infarction (2.1%). Variables influencing readmission were history of cancer (OR = 2.60, 95% CI 1.13-6.03, p = .025) and the patients who went to a home rather than a hospital after discharge (OR = 2.91, 95% CI 1.33-6.36, p = .008), as a type of valve surgery, mitral valve valvuloplasty had a higher readmission rate than aortic valve replacement (OR = 1.21, 95% CI 1.21-4.98, p = .012). In order to reduce unplanned readmissions, an tailored education program is needed to enable patients and caregivers to manage their comorbid chronic diseases before discharge and assess risk factors for readmission in advance.

• Journal of Chest Surgery
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• v.33 no.11
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• pp.869-875
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• 2000

배경: 뇌혈관계 합병증은 관상동백우회술 후 발생하는 사망률 중 10% 이상을 차지하는 치명적인 질환이다. 최근들어 고령 환자, 고혈압, 당뇨병 등이 병발하고 고 위험군에 대한 수술이 증가하면서 뇌혈관계 합병증은 오히려 증가하고 있다. 본 연구는 관상동맥우회술을 받은 환자의 의무기록을 조사하여 관상동맥우회술 후 발생되는 뇌혈관계 질환의 위험 인자를 밝히고자 한다. 대상 및 방법: 1991년 3월부터 1999년 7월 사이에 관상동맥우회술을 받은 185명을 조사하여, 뇌혈관계 합병증의 위험 인자들을 통계적으로 검증하였다. 결과: 뇌혈관계 합병증의 유병율은 7.57%(14명)였으며 이중 5예는 사망하였다. 동 기간 중 전체 사망은 11예이므로 사망자의 45.5%가 뇌혈관계 합병증으로 사망한 것이다. 통계적의의가 있는 뇌혈관계 합병증 위험 인자로는 수술 후 부정맥(p=0.0064), 기왕의 뇌혈관계 병력(p=0.0090), 체외순환시간(p=0.0181), 대동맥의 동맥경화(p=0.03575) 및 당뇨병(p=0.0452) 등이었다. 경동맥협착이 동반되어 경동맥 혈관내막 절제술(carotid endarterectomy)을 동시에 시술한 경우는 2예였으나, 뇌혈관계 합병증은 발생하지 않았다. 75세 이상의 고령환자는 3명이었으며 모두 뇌혈관계 합병증은 발생하지 않았다. 결론: 관상동맥우회술 후 발생하는 뇌혈관계 질환과 통계적으로 유의한 위험요인은 수술 후 부정맥, 뇌혈관이상의 기왕력, 체외순환시간, 대동맥궁의 동맥경화, 당뇨 등이었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4943-4952
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• 2013

This study was conducted among Korean women over aged 60 who participated in Korea National Health and Nutrition Examination Survey (KNHANES) (the 2nd and 3rd year at the 4th survey, and the 1st year at the 5th survey). The purpose of the study was to figure out a relation between femoral neck and lumbar spine bone mineral density and anthropometry, life style, diet, fracture history, family history of osteoporosis, medical history, menstrual history and reproductive factor. To express the strength of the associations, percent differences were calculated from multiple linear regression models using the formula ${\beta}{\times}$(unit/mean BMD). Unit for continuous variables were chosen to approximate 1 standard deviation(SD). In women aged 60 or older, lean mass(B: 0.257) and fat mass(B: 0.237) greatly influenced bone density in the femoral neck and lumbar spine. Therefore it will be an effective way to prevent osteoporosis for elderly women by increasing lean mass and maintaining proper weight.