• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.580-586
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• 2016

The ultra-long stroke engine was developed to generate greater power at lower speeds than previous designs to enhance the propulsion efficiency. The torsional exciting force, on the other hand, was increased significantly. Therefore, it is possible to control the torsional vibration of its shaft system equipped with the fuel efficient ultra-long stroke engine by adopting a damper although the torsional vibration could be controlled adequately by applying tuning and turning wheels on the engine previously. In this paper, the dynamic characteristics of a viscous-spring damper used to control the torsional vibration of the corresponding shaft system are reviewed and then examined to determine what vibration characteristics might be used to optimize the viscous-spring damper. In some cases, operators of eco-ships have recently experienced the problem of delayed RPM acceleration. It has been suggested that the proper measures for controlling the torsional vibration in the shaft system should involve adjusting the design parameters of its damper determined by the optimum damper design theory to avoid the fatigue damage of shafts.

• Journal of Preventive Medicine and Public Health
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• v.15 no.1
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• pp.57-73
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• 1982

Questionaires on symptoms of respiratory disease have been used in Korea to elicit the probable health effects of air pollution in epidemiologic studies: The objectives of such studies often include comparing prevalence of symptoms of respiratory system between different population groups or between the same population groups, at different times. Unfortunately, little attention has, been paid to standardization of those questionaires, whether those are Korean. versions or not. Furthermore, no attempt to develop Korean ,questionaire on respiratory symptoms and relevant information has been made. Followed by 'a comparative study on responses to Korean version questionaires(English origin) of CMI, MRC, and ATS-DLD-78' two types of questionaires on respiratory symptoms and relevant information for Korean adult, which are short form (SUN-81-AS) and long forms (optional questions are added to the short one, SUN-81-AL), have been designed suitable to Korean background by authors (see Annex). The self-administered and closed-question questionaire were tested their validity and reliability by administration to l80 normal adults (medical and nursing students) and 60 clinical patients of Seoul National University Hospital, with spirometric exam. The results obtained and conclusions drawn are as follow: 1. It took less than 10 minutes to complete the questionaire SNU-81-AS and SNU-81-AL. 2. The test-retest reliability of each questions in AS and AL ,were observed as 92.7% and 92.1%, respectively. And all of the level of agreement are statistically significant with kappa statistic. 3. In addition to higher prevalence rate of symptoms in patients group compared, with, normal. group, the correlations between FEV 1.0/FVC predictive value(%) and number of symptoms were statistically significant inpatients group (See Fig. 1 and, Table 7). 4. The answer rate to optional questions in AL form among those who are not to do was about 10%, while the no-answer rate among who are to do was about 15% in Normal (medical and nursing students) group. 5. From the viewpoints of validity and reliability, the new Korean questionaire (SNU-81-AS and AL) developed by authors are to be recommendable to use in epidemiologic studies on respiratory illness in Korea. The self-administration, however, of optional questions in AL form may not assure the quality of data gathered.

• Tuberculosis and Respiratory Diseases
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• v.55 no.2
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• pp.140-153
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• 2003

Background : The cell-mediated immune reaction to tuberculosis infection involves a complex network of cytokines. The extent of inflammation, tissue damage and severity of the disease suggested to be determined by the balance between extent and duration of the proinflammatory cytokine response versus those of the suppressive cytokines. The systemic cytokine response in pathogenesis of tuberculosis can be assessed by measuring serum cytokine levels. Method : Serum interleukin-1 beta(IL-$1{\beta}$), IL-2, IL-4, IL-6, IL-10, IL-12(p40), tumor necrosis factor-alpha(TNF-${\alpha}$), interferon-gamma(IFN-${\gamma}$) and transforming growth factor-beta(TGF-${\beta}$) levels were measured in 83 patients with pulmonary tuberculosis, 10 patients with endobronchial tuberculosis before treatment and 20 healthy subjects by using a sandwich ELISA. In patients with pulmonary tuberculosis, they were divided into mild, moderate and far advanced group according to the severity by ATS guidelines. To compare with those of pretreatment levels, we measured serum IL-$1{\beta}$, IL-2, IL-4, IL-6, IL-10, IL-12(p40), TNF-${\alpha}$, IFN-${\gamma}$ and TGF-${\beta}$ levels in 45 of 83 patients with pulmonary tuberculosis after 2 and 6 months of treatment. Results : 1) In sera of patients with active pulmonary tuberculosis(n=83), IL-$1{\beta}$, IL-6(p<0.05), TNF-${\alpha}$, and IFN-${\gamma}$ were elevated and TGF-${\beta}$ was decreased comparing to control. IL-2, Il-12(p40), IL-4 and IL-10 were similar between the patients with tuberculosis and control. 2) In endobronchial tuberculosis, IL-6 and TNF-${\alpha}$ were elevated and TGF-${\beta}$ was decreased comparing to control. IL-12(p40) seemed to be elevated comparing to pulmonary tuberculosis. 3) Far advanced tuberculosis showed markedly elevated IL-6 and IFN-${\gamma}$ level(p<0.05). 4) The significant correlations were noted between IL-1, IL-6 AND TNF-${\alpha}$ and between IL-12, Il-2 and IL-4(p<0.01). 5) After 2 and 6 months of standard treatment, the level of IL-6 and IFN-${\gamma}$ was significantly decreased(p<0.05). Conclusion : These results showed that an altered balance between cytokines is likely to be involved in the extent of inflammation, tissue damage and severity of the disease tuberculosis. But, it should be considered diversities of cytokine response according to type of tuberculosis and immunity in clinical application and interpreting future studies.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.2
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• pp.61-114
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• 2018

Recently airspace became a hot issue considering today's international relations. However, there was no data that could be fully explained about a legal system of korean airspace, so I looked at law and practice about korean airspace together. The nation's aviation law sector is comletely separate from those related to civil and military aircraft, at least in legal terms. The Minister of Land, Infrastructure and Transport shall carry out his/her duties with various authority granted by the "Aviation Safety Act". The nation's aviation-related content is being regulated too much by the Ministry of Land, Infrastructure and Transport's notice or regulation, and there are many things that are not well known about which clauses of the upper law are associated with. The notice should be clearly described only in detail on delegated matters. As for the airspace system, the airspace system is too complex for the public to understand, and there seems to be a gap between law and practice. Therefore, I think it would be good to reestablish a simple and practical airspace system. Airspace and aviation related tasks in the military need to be clearly understood by distinguishing between those entrusted by the Minister of Land, Infrastructure and Transport and those inherent in the military. Regarding matters entrusted by the Minister of Land, Infrastructure and Transpor, it is necessary to work closely with the Minister of Land, Infrastructure and Transport when preparing related work guidelines, and to clarify who should prepare the guidelines. Regarding airspace control as a military operation, policies or guidelines that are faithful to military doctrine on airspace control are needed.

• Tuberculosis and Respiratory Diseases
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• v.44 no.4
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• pp.836-843
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• 1997

Background : The prevalence of Gastro-esophageal reflux(GER) in patients with asthma is estimated to be 50~60% and treatment of GER has been shown to improve asthma symptoms in Western. But GER has been known to be less common in Eastern and GER prevalence rates in asthmatics are not available in Korea. Method : We compared the prevalence rate of GER in 42 patients with asthma to that in 20 healthy normal controls and examed the efficacy of new prokinetic drug, cisapride(40mg/day, 8weeks) in patients with GER and asthma. For acid GER to be considered pathological, 24 hour esophageal pH monitoring should reveal values exceeding upper limit of 95 percentile for at least one of 6 parameter of DeMesseter's table. Result : The results showed GER was more common in patients with asthma(11/42, 26.2%) than normal controls(3/20, 15%) and asthmatics group showed a significant longer supine time pH<4(%) and total time pH<4(%), and more reflux episodes as compared with normal control group. After 4 asthmatics with GER were treated with cisapride, their asthma symtom scores, FEV1 and composite scores of pH monitoring were improved. Conclusion : GER is more common in asthmatics than in normal controls in Korea and prepulsid reduces asthma symptoms in patients with GER and asthma.

• Tuberculosis and Respiratory Diseases
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• v.50 no.4
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• pp.409-414
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• 2001

Background : Legionella pneumophila has been recognized as an important cause of community-acquired pneumonia(CAP) requiring hospitalization. However, epidemiological data on the occurrence of legionella-related pneumonia is unavailable in Korea. The purpose of this study was to evaluate the etiological importance of legionella pneumophila serogroup 1 in patients hospitalized with CAP. Method : The CAP patients over 16 year-old were recruited from July 1999 to June 2000 at the Chunchon Sacred Heart Hospital. Fifty four patients (male 29, female 25, average age $63.8{\pm}15.3$) were included in this study. A diagnosis of a legionella pneumophila infection was based on a urinary antigen test using the Binax Company enzyme immunoassay. The severity of pneumonia was assessed using the Fine's PORT scoring system. Result : The average Fine's PORT score was 99.7(${\pm}44.9$). According to the risk classification proposed by the Infectious Disease Society of America, the number of patients in each class(from class I to class V) were 6(11.1%), 13(24.1%), 9(16.7%), 14(25.8%), and 12(22.2%), respectively. Thirty two patients(59.3%) were initially admitted to the intensive care unit. The mortality rate was 16.7%(9 in 54). In all patients, urinary antigens to Legionella pnewnophila serogroup 1 were not detected. Conclusion : Legionella pnewnophila may play little role in causing adult CAP in Korea. Therefore, the routine use of macrolide in the empirical treatment of the CAP patients based upon the ATS guidelines(1993) in Korea should be reevaluated.