• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.205-210
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• 2001

A new single stage power factor corrected AC/DC converter has been proposed, that is unified with buck topology and suitable for universal input. The design example of the proposed converter lot 5V 12A application has been presented. The design considerations and simulation results for the proposed converter have been shown. The simulation results show that the line input current harmonics can meet IEC 1000-3-2 Class D requirements for the line input voltage from 90 to 260V.

• Tuberculosis and Respiratory Diseases
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• v.44 no.2
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• pp.232-240
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• 1997

Background : Postprimary pulmonary tuberculosis is located mainly in upper lobes. The tuberculous lesion involving the lower lobes usually arises from the upper lobe cavity through endobronchial spread. When tuberculosis is confined to the lower lung field, it often masquerades as pneumonia, lung cancer, bronchiectasis, or lung abscess. Thus the correct diagnosis may be sometimes delayed for a long time. Methods : We carried out, retrospectively, a clinical study on 50 patients confirmed with lower lung field tuberculosis who visited the Department of Pulmonary Medicine at Hanyang University Hospital from January 1992 to December 1994. The following results were obtained. Results : Lower lung field tuberculosis without concomitant upper lobe disease occurred in fifty patients representing 6.9% of the total admission with active pulmonary tuberculosis over a period of 3 years. It occurred most frequently in the third decade but age distribution was relatively even. The mean age was 43 years old. Female was more frequently affected than male (male to female ratio 1 : 1.9). The most common symptom was cough(68%), followed by sputum(52%), fever(38%), and chest discomfort(30%). On chest X-ray of the 50patients, consolidation was the most common finding in 52%, followed by solitary nodule(22%) collapse(16%), cavitary lesion(10%), in decreasing order. The disease confined to the right side in 25 cases, left side 20 cases, and both sides 5 cases. Endobronchial tuberculosis (1) Endobronchial involvement was proved by bronchoscopic examination in 20 of 50patients. (2) Mean age was 44years old and female was more affected than man (male to female ratio 1 : 3). Sputum AFB stain and Mycobacterium tuberculosis culture were positive only in 50% of cases unlikely upper lobe tuberculosis, additional diagnostic methods were needed. In our study, bronchoscopic examination and percutaneous fine needle aspiration biopsy increased diagnostic yield by 18% and 32%, respectively. The most common associated condition was diabetes mellitus(18%) and others were anemia, anorexia nervosa, stomach cancer, and systemic steroid usage. Conclusion : When we find a lower lung field lesion, we should suspect tuberculosis if the patient has diabetes mellitus, anemia, systemic steroid usage, malignancy or other immune suppressed states. Because diagnostic yield of sputum AFB smear & Mycobacterium tuberculosis culture was low, additional diagnostic methods such as bronchoscopy and fine needle aspiration biopsy were needed.

• Journal of the Korea Society for Simulation
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• v.30 no.2
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• pp.1-9
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• 2021

Many factors such as wind direction, wind strength, temperature, and obstacles affect a munition's trajectory. Since these factors eventually determines the probability of hit and the hitting point of a target, these factors should be considered to obtain reliable weapon effectiveness data. In this study, we propose the extension of the MSDL(Military Scenario Definition Language) to reflect these factors to improve the reliability of weapon effectiveness data. Based on the existing MSDL, which has been used to set the initial condition of a military simulation scenarios, the newly identified subelements are added in ScenarioID, Environment, Organizations, and Installations as a scenario schema. Also, DamageAssessment and DesignOfExperiments element are added to make weapon effectiveness data easily. The extended MSDL enables to automatically generate the simulation scenarios that reflect various factors which affect the probability of hit or kill. This extended MSDL is applied to an integrated simulation software of weapon systems, named AddSIM version 4.0 for generation of weapon effectiveness data.

• Journal of agricultural medicine and community health
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• v.16 no.1
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• pp.48-60
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• 1991

In a seroepidemiological study in several areas of Korea, the ELISA technique was performed to determine prevalence of some important helminthic diseases in our nation during March $15^{th}$ to June $30^{th}$. 1991. In this survey the serum antibody positive rates of anisakiasis, toxocariasis, clonorchiasis, paragonimiasis, cysticercosis, and sparganosis were measured. Among, 6,704 cases examined, 19.7% showed positive antibody titer at least one of the six items studied. Overall positive antibody rate was 8.1% in anisakiasis, 5.6% in toxocariasis, 3.6% in clonorchiasis, 1.7% in paragonimiasis, 4.5% in cysticercosis, and 2.6% in sparganosis respectively. In Pusan port southeastern part of Korea, antibody positive rate of anisakiasis was 2.9%, and clonorchiasis was 2.8% among 450 examine. In TaeJ$\check{o}$n city, central part of Korea. toxocariasis(6.7%) and anisakiasis(3.7%) showed high serologic positive rate. Of the 875 persons in Chunche$\check{o}$n gun(=province), northern central rural area of South Korea, anisakiasis was revealed as 3.4% seropositivity. In Tonghae port, eastern coast of South Korea. 9.9% of population examined showed positive antibody titer in anisakiasis. Of the 1,122 persons examined in Southern part of Cholla-Namdo(Southwestern coastal area of Korea), anisakiasis was 16.9%, cysticerocosis was 12.7% and the paragonimiasis was 3.3% respectively. In some localized area of Cholla-Pukdo, anisakiasis was 9.3% and cysticekosis was 4.3% among 702 cases examined. In some localized area of Kyungsang-Pukdo, anisakiasis was 10.6%. and toxocariasis was 16.1% among 900 cases examined. And finally, in Cheju-do, southern island of Korea, anisakiasis showed high positive rate(6.7%). Because cross reactions between related helminth group may disturb the analysis of these data, use of further developed techniques such as EITB(enzyme-linked immunoelectrotransfer blot) was considered as a essential tools for the study. We thought that probably most of the positive cases of cysticerosis were taeniasis cases. We can't rule out taeniasis even though EITB was employed as far as crude worm extract or cystic fluid of cysticercus was used as antigen. It was well Known that toxocariasis and anisakiasis also showed cross reactivity. However, the data presented here focus on seropositive rate of several helminthic diseases in Korea, not true prevalence rate of helminthiases, and to wait for more expensive purified antigen in sufficient amount for epidemiologic use is not necessary because increased immunologic sensitivity had little effect on epidemiologic sensitivity. We, here, suggest that ELISA should be applied as soon as possible to the evaluation of prevalence of tissue invading parasitic diseases, and a review of the antibody positive rate obtained in this study would be a basic data for controlling program of parasitic diseases in Korea.

• Radiation Oncology Journal
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• v.26 no.1
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• pp.35-44
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• 2008

Purpose: To evaluate the incidence and prognostic factors of treatment-related pneumonitis in non-small-cell lung cancer(NSCLC) patients treated with intensity modulated radiation therapy(IMRT). Materials and Methods: One-hundred-five patients with NSCLC treated with IMRT between 1 August 2004 and 30 November 2006 were analyzed retrospectively. The mean age of patients was 62.9 years, and squamous carcinomas were confirmed in 81 patients(77%). Sixty-six patients(62.9%) were classified as stage III, and 59 patients had lesions in the right lung. Twenty-seven patients were treated with a dose of 3,060 cGy preoperatively, and 10 patients were given a dose of 5,040 cGy postoperatively. Sixty-eight patients received a dose of 7,020 cGy for curative intent. Sixty-eight patients were treated with the use of the CORVUS planning system and 37 patients were treated with the use of the ECLIPSE planning system. Results: Of 105 patients, 21 patients(20%) had abnormal radiological findings, but only seven patients(6.7%) required treatment for radiation pneumonitis. Six of the seven patients had other serious lesions, including a bronchioesophageal fistula(one patient), recurrence in the treatment field(two patients), brain metastasis(one patient) and lung-to-lung metastasis(two patients); all of these patients died within 19 months after radiation treatment. Sixteen patients(23.5%) that received planning with the CORVUS system had abnormal lung findings. Five patients(13.5%) had abnormal lung findings with the use of the ECLIPSE planning system. Other prognostic factors such as perioperative radiation therapy, a volume over 10% of the V20 volume in the right lung, were also statistically significant. Conclusion: This retrospective analysis suggests that IMRT could be a beneficial treatment modality for the reduction of radiation pneumonitis in NSCLC patients. However, the higher incidence of abnormal radiological findings in perioperative patients treated with relatively lower doses($3,060{\sim}5,040$ cGy) suggest the need for judicious treatment planning in preoperative or postoperative treatment.

• Journal of Chest Surgery
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• v.29 no.11
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• pp.1248-1256
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• 1996

From June 1987 to December 1994, 372 patients underwent operation for resection of esophageal cancer, and 48 patients with metastasis to distant abdominal lymph nodes were analyzed.. The primary tumors were located predominantly in lower thoracic esophagus(n=29). The location of involved lymph nodes were celiac L/N(n=45), common hepatic L/N(n=4), paraaortic L/N(n=l), and retropancreatic L/N(n=l). Most tumors penetrated the esophageal wall(T3,T4, n=43), metastased to regional L/N(N1, n=41), but a few tumors were limited to the esophageal wall(T1,T2, n=5), metastased to distant abdominal L/N without metastasis to regional L/N(NO, n=7). Resectability rate was 87.5%(42/48), and complete resection was possible in 31 patients(64.6%). The most frequent cause of incomplete resection and unresectability was unresectable T4 lesions(n=8), extranodal invasion(n=7). Overall operative mortality and morbidity was 4.2%, 22.9%, and resection mortality was 4.8%. Adjuvant therapy was given to 27 patients, and postoperative follow-up was possible in all patients(median follow-up, 32 months). The 1 year and 3 year survival for resection group was 54.0%, 18.1%(median, 386 days) including operative deaths. Our results suggest that resection of the esophageal cancer with metastasis to distant abdominal lymph nodes(M1LYN) can be done with acceptable mortality and morbidity, and may playa role in long-term survival in carefully selected patients because prognosis is dismal in unresectable esophageal cancer. We recommend that lymph nodes around celiac axis be dissected thoroughly for exact staging and possible prolongation of survival, and multimodality therapy as necessary because most patients with M1(LYN) esophageal cancer do poorly with only primay surgical treatment.

• Parasites, Hosts and Diseases
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• v.29 no.3
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• pp.235-244
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• 1991

An epidemiological study and mass treatments of Enterobius vermicularis infection among children near Wonju area of Kangwon province were carried out. The children were divided into 4 groups according to their residing localities; children in the mountainous area, rural area, urban area and in orphanage. They were examined by adhesive cellotape anal swab technique, and egg positive rates were obtained. The rates of egg reduction and re-infection rates after repeated mass treatments were also observed. The results obtained were as follows: 1. The overall egg Positive rate of E. vermicularis in the first screening was 19.9% (251 out of 1, 262 examinees; 19.7% in males and 20.1% in females). The positive rates were 13.0% in the mountainous area, 11 9% in the rural area, 15.1% in the urban (medium-sized) area and 61.9% in orphanages. 2. The highest positive rates were observed in the kindergarten children, and 1st and 2nd grade children of primary schools (26.2~32.2%), and the lowest rate (13.6%) in 6-year grade children of primary schools. 3. Cumulative detection rates from 3 repeated anal swabs at 4~5 days interval were higher (70.8%) than those from single anal swabs (50.0~59.2%). 4. Out of the examinees who showed the highest cumulative positive rate (70.8%), about 39.2% were consecutively positive in 3 anal swabs. Among different groups of children, the higher the total egg detection rates (87.5%), the higher the consecutive positive rates (71.9%) . 5. A total of 2, 609 (male : female=1 : 12.4) worms were collected from 17 egg-positive cases treated with anthelinintics. The mean number of worms per child was 153 (range: 4-824) . 6. The egg-positive cases in several studied groups (180 children) were treated with anthelmintics 6 times at 3-week intervals. In this case, the overall positive rate was decreased from 54.8% to 2.2% at 15 weeks after the treatments, but no complete negative conversion was experienced. However, in a group of children (154 children) including egg Positive and negative cases who were both treated with anthelmintics at 3-week interval, a complete egg-negative conversion was observed in the 9th week after treatments. 7. The egg-detection rate in the brothers or sisters of egg Positive children was 70.0% (28 out of 40 examined), and the egg-positive rate according to the family unit was 69.7%. In summarizing the above results, it is concluded that Enterobius vermicularis infection is still highly prevalent among children in Korea, and that repeated mass treatments of more than 3 times will be effective for control of this infection.

• The Transactions of the Korean Institute of Power Electronics
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• v.2 no.3
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• pp.26-36
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• 1997

An single stage AC/DC converter based on half bridge topology suitable for low power level applications is proposed. The proposed converter has high power factor, low harmonic distortion, and tight output regulations. Asymmetrical control and synchronous rectification are adopted to reduce the switching loss and rectification loss, respectively. The modelling employing average modelling method and detailed analysis are performed to derive the design equations. According to these design equations, a prototype converter has been designed and experimented. This prototype meets the IEC 555-2 regulations with near unity power factor and high efficiency.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.1
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• pp.18-29
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• 2002

Generally, the single-stage power factor corrected converter has a problem of high dc link voltage. In the case of high line voltage, especially, the dc link voltage is verb high under the light load condition. To solve this problem, a new single stage power factor corrected AC/DC converter has been proposed. The proposed converter has huck topology as a power factor corrector. To prove feasibility of the proposed converter, the design example of the proposed converter has been presented. The design considerations and experimental results for the proposed converter have been shown. The experimental results show that the line input current harmonics can meet IEC1000-3-2 Class D requirements for the range of line input voltage from 90Vrms to 260Vrms.

• Journal of Chest Surgery
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• v.34 no.2
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• pp.156-161
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• 2001

배경: 식도암의 절제술에 있어 식도 위 문합술은 중대한 합병증, 즉 문합부 누출, 양성협착, 종양의 재발 등을 유발한다. 수술 후 재원기간동안 환자가 느끼는 주관적인 증상과 합병증이 식도와 위장관의 문합부 위치에 따라 달라질 수 있으므로 서로간에 비교분석할 필요가 있겠다. 대상 및 방법: 1995년 1월부터 1999년 5월까지 식도암 근치술로 식도 위 문합술을 시행 받은 55명의 환자를 대상으로 문합위치에 따라 경부문합한 23명의 환자와 흉부문합을 한 32명의 환자를 비교 분석하였다. 절제술 후 AJCC분류에 따라 I기 5명, II기 27명, III기 23명으로 판정되었으며, 종양이 상흉부에 위치한 경우 3명, 중흉부 34명, 하흉부 18명이었다. 조직학적으로 55명의 환자 2명의 선암을 제외하고 53명이 편평상피세포암이었다. 55명 전원이 남자였으며 평균연령은 경부문합의 경우 59세였고, 흉부문합은 55세였다. 경부 문합의 경우 1명의 staple봉합을 제외하고 나머지 22명이 수봉합을 하였으며, 흉부문합술의 경우는 9명이 수봉합, 23명이 staple봉합을 하였다. 결과: 수술 후 사망자는 경부문합 1명, 흉부문합 2명이었다. 경부 문합환자의 경우 23명 중 15명에서 호흡기, 소화기등의 합병증 46례가 발생하였고, 흉부 문합환자의 경우 32명중 13명에서 합병증 37례가 발생하였다. 경부문합환자는 중등도 혹은 심한 연하곤란을 나타내는 경우가 11명에서 있었으며, 흉부문합환자는 2명에서 나타났다. 또한 수술 후 20일 이후까지 재원한 경우는 경부문합환자 18명, 흉부문합환자는 13명이었다. 결론: 식도암에서 식도 위 문합술의 경우 호흡기, 소화기, 감염등의 합병증이 발생하였으며, 특히 호흡기 합병증에 의한 사망률이 높았다. 문합부 누출은 staple봉합보다 수봉합에서, 흉부문합보다 경부문합에서 빈도가 높았다. 경부문합의 경우 문합부 누출률이 높고, 연하곤란을 많이 호소하며 재원기간이 의미있게 길었다.