• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.1
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• pp.21-30
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• 2022

The restart of scramjet engine is almost impossible in case its unstart happens during engine operation. Therefore, it is essential to prognosticate the scramjet engine unstart phenomena. A numerical simulation of a scramjet engine is conducted to investigate the unstart process of the scramjet engine by adjusting the backpressure at the isolator outlet to the engine analysis environment. The start and unstart of the engine are identified by applying a support vector machine (SVM) through the data measured by wall pressure so that the locations of the pressure sensors most suitable for the unstart detection are selected. And the operation conditions in which the engine is avoid to be unstarted are quantified to perceive the safety margin.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.435-435
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• 2018

하천은 다양하게 분류되고 다양한 식물, 동물, 어류 등이 살아가고 있는 서식처이다. 이러한 하천의 환경 상태를 판단하고 진단하기 위해 올바르게 하천을 평가할 방법이 필요하다. 국내에서는 1910년대부터 1940년대 중반까지의 하천사업은 수력발전을 위한 대규모 댐 개발과 평야지대 관개를 위한 저수지 축조 등 이수사업에 치중하였다. 이후 1960년대부터 1970년대에는 도시와 공단의 개발, 교통, 수자원, 상하수도, 전력 등 사회간접자본의 집중적인 개발을 하였다. 여기서 하천에 초점을 맞추면 하천변의 치수를 위한 하천개수 사업, 그리고 도시화에 따른 도시 소하천의 복개를 들 수 있다. 그러나 이러한 도시화와 산업화는 하천의 오염과 함께 하천의 인공화라는 바람직하지 못한 결과를 가져왔다. 대부분의 도시하천은 직선화되고 높은 콘크리트제방과 콘크리트호안공, 무분별한 하천변의 개발 등으로 인한 황폐화되고 더 이상 하천을 이용할 수 없게 되었다. 국내 하천의 건강성을 평가하기 위한 수많은 하천평가방법들이 연구되었다. 대표적으로 '우리나라 중소하천 코리도의 자연성 평가기법 연구'(조용현, 1997), 생태환경복원을 위한 하천자연도평가 기준에 과한 연구(김동찬 박익수, 1999), 수생태계 건강성 조사 및 평가의 서식수변환경 평가(환경부, 2008) 등이 연구되어 왔으며, 몇몇 평가방법들은 많은 프로젝트에 사용되어 국내 하천의 자연성을 보여주고 있다. 많은 평가방법은 각각의 평가방법과 평가기준을 가지고 하천을 평가하고 있다. 하지만 이 많은 평가방법들의 평가기준, 평가결과 가 하천환경의 상태를 파악하고 진단할 수 있는지에 대한 연구가 전무한 상태이다. 우리나라에서 자연도 평가에 대해 연구를 시작한 것은 90년대 이후였다. 지금까지는 많은 연구와 프로젝트가 진행되어 왔지만 다양한 평가방법들에 대한 비교연구가 없었다. 다기능 하천실험사업(한국건설기술연구원, 2007, 2008)에서 LAWA를 이용해 하천의 물리적 평가를 하고 물리적 구조항목간의 상관분석, 저서성 대형 무척추 동물과 하천 물리적 구조의 상관분석, 식물과 하천 물리적 구조의 상관분석을 실시한 적은 있지만 서로 다른 하천의 물리적 평가방법을 가지고 비교연구를 실시한 적은 없다. 때문에 국내 하천의 물리적 평가 중 어떤 방법이 국내 하천의 현황을 잘 판단하고 있는지, 객관적으로 평가하는지, 복원계획을 수립할 때 효과적인 복원방안을 제시하는지 연구할 필요가 있다. 본 연구는 국내 하천 자연도 평가 방법을 살펴보고 평가항목의 적합성을 도출하고자 하였으며, 하천 자연도 평가항목의 중요도를 선정하여 하천 실무자들이 간편하게 사용할 수 있는 실용적인 방법을 제시하고자 하였다.

• Tuberculosis and Respiratory Diseases
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• v.40 no.3
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• pp.274-282
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• 1993

Background: Pulmonary paragonimiasis is caused by consumption of raw or improperly cooked crabs infected by a laval stage (metacercaris) of the parasite. In our country it had been a highly prevalent endemic disease until th late 1960s, and after then it's prevalence has been markedly decreased. But because some people have continued to ingest undercooked crabs, this disease have yet occured sporadically. Methods: We reviewed the clinical and radiological findings retrospectively in seventy-four patients of pulmonary paragonimiasis including familial infestation in 7 familes (20 cases) who were confirmed by food history, clinical and radiological findings, and labaratory data. Results: The male: female ratio was 2.2:1 and most prevalent age was 40-49 years old. Twen6ty nine patients (39%) had ova-positive infection. The detection sites were sputum (48%), pleural fluid (17%), fine needle aspiration biopsy of nodular or cystic lesion (17%), pleural biopsy (7%), skin nodule biopsy (7%), and stool (3%). The patients had pulmonary symptoms in 63 cases (85%) but 9 cases did not have any symptoms. The 53 cases (72%) had abnormal radiological findings in lung parenchyme (75%) and pleura (63%). However 21 cases (28%) showed no specific findings in their chest X-ray. Serum titers (ELISA) of specific IgG for paragonimiasis in 13 cases were followed for average 9.8 months after treatment, which showed slow decreasement. In the evaluation of family member (7 family, 20 cases), all members having the common dietary history together with a proven patients were confirmed this disease by serological test, regardless of the presence or the abscence of clinical or radilogical symptoms. Conclusion: We evaluated the clinical and radiological findings in 74 cases of pulmonary paragonimiasis including 7 family members who had a history of ingestion of improperly cooked crabs together with patients. The paients of pulmonary paragonimiasis have various findings in clinical and radiological findings. Common diet exposure history and laboratory findings including specific IgG were important in earlier diagnosing and treating in family members of patients.

• Tuberculosis and Respiratory Diseases
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• v.42 no.2
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• pp.175-183
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• 1995

Background: The incidence of mycoplasmal pneumonia is predominantly at childhood and early adulthood, but in adults, its incidence is low and its symptoms and physical findings are nonspecific. The definite diagnosis of M. pneumoniae pneumonia can be made by sputum culture, but requires several weeks for positive results, and the early diagnosis must initially be based on the serologic tests and appropriate clinical findings. Thus, we evaluated the clinical aspects of M. pneumoniae pneumonia in the adults patients. Method: Among the admitted patients due to pneumonia, the definite diagnosis is anti-M. pneumoniae antibody titer of $\geq$ 1:40 and a single cold agglutinin titer of $\geq$ 1:64. The presumptive diagnosis is anti-M. pneumoniae antibody titer of $\geq$ 1:40 or a single cold agglutinin titer of $\geq$ 1:64 and the clinical characteristics or chest X-ray findings are compatible with M. pneumoniae pneumonia. We studied the age and sex distribution, seasonal distribution, clinical symptoms, physical findings, serologic test, chest X-ray findings, treatment and its progression. Results: 1) The age distribution was even and the ratio of male to female was 1:1. 2) The monthly distribution was most common in January(16.7%) and the seasonal distribution in autumn and winter(autumn: 30%, winter: 33.3%). 3) The cold agglutinin titers were higher than 1:64 in 12 cases(40%), and reached the peak level around 2 weeks from onset and antimycoplasma antibody titers were higher than 1:160 in 5 cases(16.7%). 4) On the chest X-ray, pulmonary infiltration was noted in 28 cases(93.3%) among 30 cases and right lower lobe involvement was the most common(33.3%) and both lower lobe involvement was noted in 7 cases(23.3%). 5) The mean treatment duration was most common(33.3%) in 1 week to 2 weeks after admission and 26 cases(86.7%) were improved within 4 weeks. 6) On admission, there was fever(${\geq}38.9^{\circ}C$) in 17 cases(56.7%), and the fever subsided in 12 cases(70%) within 3 days after treatment using erythromycin. Conclusion: The mycoplasmal pneumonia in adults shows milder clinical patterns than that in childhood and can be completely recovered without complication by early diagnosis and treatment.

• Tuberculosis and Respiratory Diseases
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• v.41 no.1
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• pp.26-35
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• 1994

Background: Bronchioloalveolar cell carcinoma today needs further studies as an early diagnosis will drastically improve the chances of cure. Methods: Twenty-four cases of bronchioloalveolar cell carcinoma for the period of 5 years were studied in terms of incidence, age, sex, underlying diseases, symptoms, radiographic findings, methods of diagnosis, clinical and pathologic staging, methods of treatment, and survival retrospectively. Results: No correlation was found between patients' age, sex and underlying diseases. Most common symptoms were cough(62.5%), chest pain(29.2%), and sputum(29.2%). Of the 24 cases, 13 patients(54.2%) had solitary nodule, 6 patients(25%) had multiple nodules. At the time of diagnosis, 3 patients(12.5%) had the stage I diseases, 3 patients(12.5%) had the stage II diseases, 4 patients(16.7%) had the stage IIIa diseases, 3 patients(12.5%) had the stage IIIb diseases, and 11 patients(45.8%) had the stage IV diseases. 14 cases(58.3%) were found inoperable at the time of admission; they all died within 17 months. In 7 cases with stage I, II, IIIa diseases curative resection were attempted, in 1 case with stage IV disease wedge resection for palliative management was performed, and in 4 cases patients were still alive at the time of conclusion of this study. Conclusion: We conclude that early diagnosis of disease will increase operability and improve chances of survival and that aggressive diagnostic workup for suspicious pulmonary infiltrate is essential as early operation offers the best chances of cure.

• Tuberculosis and Respiratory Diseases
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• v.41 no.2
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• pp.144-151
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• 1994

Background: Miliary tuberculosis almost always results from the discharge of infected caseous material into the blood stream, usually from a well hidden lymph node in the presentation of this disease in the past four decades, and although it is seen less frequent1y today than previously, its presentation and manifestation may require greater suspicion and diligence by the physician. We investigated the clinical characteristics, predisposing factors and accompanying diseases of miliary tuberculosis and tried to acquire the early diagnosis and treatment of this disease. Methods: A retrospective clinical study was done on 40 cases of miliary tuberculosis admitted to Hanyang University Hospital from Mar. 1989 to Dec.1992. The study investigated age and sex distribution, seasonal distribution, duration of symptoms before admission, pre-disposing factors, clinical symptoms, biochemical findings, chest X-ray findings, extrapulmonary tuberculosis associated with miliary tuberculosis, prognosis and mortality rate. Results: 1) The patients were most common in the age group between 20 and 29(23%) and the ratio of male to female was 1.4:1(male 23 : female 17). 2) Sputum smears for tubercle bacilli were positive in 5 cases(13%). 3) The most common clinical symptoms were fever with chilling(47.5%), coughing(47.5%), second most common symptom was dyspnea(32.5%), and the physical findings on admission were tachycardia(30%), weight loss(27.5%), meningeal signs(17.5%) in order. 4) The predisposing factors were heavy alcohol drinking(6 cases), steroid use(3 cases), pregnancy(2 cases) etc. 5) The chest X-ray findings on admission were miliary shadow only(40%), in addition pneumonic infiltration, pleurisy, and calcification in order. 6) The extrapulmonary tuberculosis associated with miliary tuberculosis were tuberculous meningitis(30%), bone and joint tuberculosis(17.5%), intestinal tuberculosis(15%) in order. 7) Biochemical findings were increased SGOT/SGPT(32.5%), increased alkaline phosphatase(32.5%), hypoalbuminemia(15%), hyponatremia(15%) etc. 8) About 4-6 weeks later after treatment(INH, RFP, PZA, EMB), 26 cases(65%) were improved on clinical symptoms or chest X-ray, 12 cases(30%) were stationary or aggravated, and 2 cases(5%) were died. Conclusion: For the early diagnosis and treatment of miliary tuberculosis, we must see its presentation and manifestation with greater interest and suspicion and investigate its predisposing factors and accompanying diseases.

• Tuberculosis and Respiratory Diseases
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• v.48 no.3
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• pp.357-364
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• 2000

Background : Complicated exudative pleural fluid collections have traditionally been treated by either closed tube thoracostomy drainage or by open surgical drainage. Complete drainage is important in order to control pleural sepsis, restore pulmonary function, and entrapment. Recently intracavitary fibrinolytic therapy has been advocated as a method to facillitate drainage of complicated exudative pleural effusion and to allow enzymatic debridemant of the restrictive fibrinous sheets covering the pleural surface. The purpose of this study is to prospectively evaluate the effects of image-guided catheter drainage with high dose urokinase(UK) instillation in the treatment of complicated pleural effusions. Patients : Twenty complicated pleural effusion patients that poorly respond to image-guided drainage were allocated to receive UK. There were 8 pneumonia and 12 tuberculosis. Methods : Drugs were diluted in 250 mL normal saline and were infused intrapleurally through the chest tube or pig-tail catheter in a daily dose of 250,000 IU of UK. Response was assessed by clinical outcome, fluid drainage, chest radiography, pleural ultrasound and/or computed tomography. Results : The mean UK instillation time was $1.63{\pm}0.10$. The mean volume drained UK instillation was $381.3{\pm}314.4\;mL$, and post-UK was $321.6{\pm}489.5\;mL$. The follow up duration after UK therapy was mean $212.9{\pm}194.5$ days. We had successful results in 19 cases (95.0%). There were 12 pleural thickenings (60.0%), 2 markedly decreased effusions (10.0%) and 5 cases of no thickening or effusion. There was recurrence after treatment in only one patient(5%) with complicated pleural effusiondue to tuberculosis. Conclusions : Image-guided drainage with high dose UK instillation (250,000 U/day) in complicated pleural effusion is a safe and more effective method than closed thoracostomy drainage. And this management, in turn, can obviate surgery in most cases.

• Tuberculosis and Respiratory Diseases
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• v.54 no.4
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• pp.439-448
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• 2003

Background : Surfactant protein B(SP-B) and surfactant protein C(SP-C) are important in accelerating surface spreading of surfactant phospholipid. The glucocorticoids accelerate the morphologic differentiation of epithelial cells into type II cells and increase the rate of phosphatidylcholine synthesis. The hydrophobic surfactant protein has been shown to be upregulated by glucocorticoids in vitro, however, its regulation in vivo is not well established. Methods : The authors investigated the effects of glucocorticoid on the accumulation of mRNA encoding SP-B and SP-C protein content of the lung. Adult rats were given different doses of subcutaneous dexamethasone and sacrificed at 24 hours and 1 week. SP-B and SP-C mRNA were measured by a filter hybridization method. Results : 1) The accumulation of SP-B mRNA at 24 hours after 0.2 mg/kg dexamethasone treatment was increased by 23.7%. 2) The accumulation of SP-B mRNA at 1 week after 2 mg/kg dexamethasone treatment was significantly increased by 96.6%(P<0.001). 3) The accumulation of SP-C mRNA at 24 hours after 0.2 mg/kg dexamethasone treatment was significantly increased by 42.7%(P<0.01). 4) The accumulation of SP-C mRNA at 1 week after 2 mg/kg dexamethasone treatment was significantly increased by 60.0% (P<0.01). Conclusion : The authors concluded that dexamethasone treatment in vivo resulted in increased levels of SP-B mRNA and SP-C mRNA. These results suggested that dexamethasone stimulates the synthesis of hydrophobic proteins associated with surfactant.

• Tuberculosis and Respiratory Diseases
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• v.41 no.6
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• pp.624-631
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• 1994

Background: Genus of Aspergilli are ubiquitous saprophytic molds in nature, but its change from a saprophytic fungus to a pathogenic organism has occurred since the use of various antibiotics. The fungus affects the chronically ill and debilitated population. Recently frequency of the fungal infection is increasing in Korea with abuse of antibiotics and glucocorticoids. Method: We analyzed medical records of 52 patients with pulmonary aspergillosis seen at Hanyang University Hospital from 1980 to 1994. The results were as follows; Results: 1) Ages ranged between second to eighth decades with majority(50%) in the fourth to fifth decades. The male to female ratio was 1.1:1. 2) Hemoptysis and productive cough, the leading symptoms, occurred in 42.3% and 25% respectively. 3) On chest X-ray fingings, the characteristic "fungus ball" pattern were observed in 53.8% of the 52cases. 4) Sputum culture for aspergilli were positive in 21.6% of the cases. We performed fine needle aspiration in 22 patients and the diagnostic yield was 100%. 5) Thirty-six patients had history of treatment with antituberculous drugs under diagnosis of pulmonary tuberculosis for an average of 27.3 months. But sputum analysis for acid-fast bacilli were positive in 5.6%(2cases of 36cases), and postoperative pathologic findings showed that 38.9%(12 cases of 28cases) were combined with tuberculosis. 6) Right upper and left upper lobes were predominantly involved(34.6% and 19.2% respectively) and lobectomies were performed in 21 cases. 7) Underlying diseases were present in 47 cases and 48.9% of them were pulmonary tuberculosis. Conclusion: These results showed that pulmonary aspergillosis usually develops in patients with open cavitary pulmonary tuberculosis. And we must consider the possibility of pulmonary aspergillosis in a patient with hemoptysis and cavitary lung lesion.