• Journal of Chest Surgery
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• 제31권12호
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• pp.1165-1171
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• 1998

배경 : 인공판막치환술을 받은 환자에서 인공판막의 기능부전이나 합병증으로 재치환술의 빈도가 증가하고있는 추세이다. 본 논문은 인공심장판막에 대한 재치환술시 위험인자를 분석하여 향후 수술성적을 향상시키는데 도움을 얻고자 하였다. 대상 및 방법: 1985년 1월부터 1996년 7월까지 계명대학교 흉부외과학교실에서 인공심장판막질환에 대한 재치환술을 받은 124예에 대하여 술전 임상적 소견 및 수술성적을 중심으로 분석하였다. 이중 3예는 2차로 재치환술은 받은 경우였다. 심장판막재치환술의 원인으로 조직판막자체의 구조적 실패가 96례(77.4%)로 가장 많았고 판막혈전증 16례(12.9%), 심내막염 7례(5.6%), 판막주위누출 5례(4.1%)가 있었다. 결과: 심장판막재치환술의 병원사망률은 8.9%였고, 술후 사망원인으로는 저심박출증이 가장 많았다(70.6%). 생존군과 사망군의 비교에서는 NYHA functional class, 혈중 크레아티닌 수치, LVSD, 체외순환시간이 사망군에서 유의하게 높았다(p < 0.05). 재치환술후 병원사망의 술전 위험인자들로는 LVSD, NYHA functional class IV, 혈중 크레아티닌 수치 등이었으며( p < 0.05), 연령이나 성별, 흉부 엑스선상 심흉곽의 비 등은 위험인자가 되지 못하였다. 결론: 술전의 임상적 소견중 LVSD, NYHA functional class, 혈중 크레아티닌 수치 등이 재치환술후의 예후를 추측할 수 있는 술전 인자라는 것을 알 수 있었다. 그리하여 심장판막재치환술은 심장 및 신기능이 악화되기 이전에 가능한한 조기에 시행하는 것이 바람직하리라 생각된다.

• 한국환경생태학회지
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• 제18권4호
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• pp.359-368
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• 2004

본 연구는 최근 자연체험형 여가휴양 공간으로 이용이 커지고 있는 도시자연공원 탐방로의 분포와 훼손특성을 파악하여 향후 자연보전형 탐방로 정비의 방향을 설정하기 위한 기초 자료 제시를 목적으로 수행하였다. 연구대상지는 계양공원, 백마공원, 약사공원, 문학공원, 청 량공원이었다. 이들 공원은 인천시 남북녹지축에 위치하여 도시생태계 보전의 핵심지역이 되고 있는 산지형 도시자연공원이며 등반형 탐방이 많이 일어나는 곳이다. 주 탐방 노선수는 계양공원 42개, 백마공원 43개, 약사공원 9개, 문학공원 28개, 청량공원 22개로서 면적에 비해 과도한 탐방로가 있었으며 샛길이 늘어나고 있는 것으로 추측되었다. 연구대상지 탐방로의 평균 나지노폭은 3.5m, 평균 최대침식 깊이는 21.3cm로 나타났고 체계적인 정비가 없을 경우 훼손은 급격히 증가될 것으로 판단되었다. 훼손이 심해 복구가 요구되는 산림환경피해도 등급 5, 6등급의 비율은 19.6∼78.0%에 달했다. 연구결과에 기초하여 인천 남북녹지축상의 산지형 도시자연공원 탐방로의 정비와 관리방안을 제안하였다.

• 한국환경복원기술학회지
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• 제9권4호
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• pp.24-35
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• 2006

The vascular plants of the studied area was listed 384 taxa of 90 families, 234 genera, 331 species, 1 subspecies, 45 varieties and 7 forms. The flora of each reservoir, 285 taxa of 83 families, 190 genera, 247 species, 1 subspecies, 30 varieties, 7 forms in Osongjae, 117 taxa of 39 families, 87 genera, 100 species, 17 varieties in Ogongjae, 83 taxa of 30 families, 67 genera, 73 species, 8 varieties, 2 forms in Shinyongjae and 86 taxa of 33families, 70 genera, 75 species, 1 subspecies, 10 varieties in Eodujae. Based on the list of the rare plants by the Forest Research Institute, 3 taxa were recorded in the studied areas; Magnolia kobus (Preservation priority order : No. 187), Penthorum chinense (No. 144), Prunus yedoensis (No. 110) and based on the list of Korean endemic plants, 4 taxa were recorded; Populus tomentiglandulosa, Clematis trichotoma, Prunus yedoensis, Paulownia coreana. Specific plant species by floral region were total 15 taxa; Prunus yedoensis in class V, 2 taxa (Carex idzuroei, Magnolia kobus) in class IV, 2 taxa (Monochoria korsakowi, Poncirus trifoliata ) in class III, 10 taxa (Sagittaria aginashi, Salix glandulosa, Clematis brachyura, Nymphoides peltata, etc.) in class I. The naturalized plants in this site were 13 families, 29 genera, 43 species, 1 varieties, 44 taxa and naturalization rate was 11.5% and based on the list of an ecosystem disturbance plants, 3 taxa were recorded in the studied areas : Paspalum distichum, Solanum carolinense, Ambrosia artemisiifolia var. elatior. The hydrophytes was listed 31 taxa of 15 families, 20 genera, 29 species, 2 varieties and Eleocharis mamillata var. cyclocarpa, Penthorum chinense, Soirodela polyrhiza were recorded in Osongjae, Sagittaria aginashi, Eleocharis kuroguwai, Scirpus juncoides, Scirpus triqueter, Monochoria korsakowi, Monochoria vaginalis var. plantaginea were recorded in Ogongjae. Besides, Scirpus fluviatilis, Trapa pseudoincisa were recorded in Shinyongjae and Scirpus triangulatus, Nymphoides peltata, Myriophyllum verticillatum were recorded in Eodujae. This site is located in the urban area and ecosystem-disturbing wild animal and plant has been imported here, therefore ecosystem has been disturbed more and more. The wetland here rapidly has changed into upland, so it needs conservation measures through long-term monitoring.

• Journal of Chest Surgery
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• 제28권1호
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• pp.23-30
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• 1995

From January 1985 to December 1992, of 1257 patients who underwent a heart valve replacement 210 [16.8% underwent reoperation on prosthetic heart valves, and 6 of them had a second valve reoperation. The indications for reoperation were structural deterioration [176 cases, 81.5% , prosthetic valve endocarditis [25 cases, 11.6% , paravalvular leak [12 cases, 5.6% , valve thrombosis [2 cases, 0.9% and ascending aortic aneurysm [1 case, 0.4% . Prosthetic valve failure developed most frequently in mitral position [57.9% and prosthetic valve endocarditis and paravalvular leak developed significantly in the aortic valve [40%, 75% [P<0.02 . Mean intervals between the primary valve operation and reoperation were 105.3$\pm$28.4 months in the case of prosthetic valve failure, 61.5$\pm$38.5 months in prosthetic valve endocarditis, 26.8$\pm$31.2 months in paravalvualr leak, and 25.0$\pm$7.0 months in valve thrombosis. In bioprostheses, the intervals were in 102.0$\pm$23.9 months in the aortic valve, and 103.6$\pm$30.8 months in the mitral valve. The overall hospital mortality rate was 7.9% [17/26 : 15% in aortic valve reoperation [6/40 , 6.5% in reoperation on the mitral prostheses [9/135 and 5.7% in multiple valve replacement [2.35 . Low cardiac output syndrome was the most common cause of death [70.6% . Advanced New York Heart Association class [P=0.00298 , explant period [P=0.0031 , aortic cross-clamp time [P=0.0070 , prosthetic valve endocarditis [P=0.0101 , paravalvularr leak [P=0.0096 , and second reoperation [P=0.00036 were the independent risk factors, but age, sex, valve position and multiple valve replacement did not have any influence on operative mortality. Mean follow up period was 38.6$\pm$24.5 months and total patient follow up period was 633.3 patient year. Actuarial survival at 8 year was 97.3$\pm$3.0% and 5 year event-free survival was 80.0$\pm$13.7%. The surgical risk of reoperation on heart valve prostheses in the advanced NYHA class patients is higher, so reoperation before severe hemodynamic impairment occurs is recommended.

• 한국지능시스템학회논문지
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• 제24권6호
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• pp.646-650
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• 2014

본 논문에서는 다차원 문제로 인하여 발생하는 패턴 분류 성능의 저하를 방지 하여 퍼지 패턴 분류기의 성능을 개선하기 위하여 다수의 Feature들 중에서 패턴 분류 성능 향상에 기여하는 Feature를 선택하기 위한 새로운 Feature Selection 방법을 제안 한다. 새로운 Feature Selection 방법은 각각의 Feature 들을 퍼지 클러스터링 기법을 이용하여 클러스터링 한 후 각 클러스터가 임의의 class에 속하는 정도를 계산하고 얻어진 값을 이용하여 해당 feature 가 fuzzy pattern classifier에 적용될 경우 패턴 분류 성능 개선 가능성을 평가한다. 평가된 성능 개선 가능성을 기반으로 이미 정해진 개수만큼의 Feature를 선택하는 Feature Selection을 수행한다. 본 논문에서는 제안된 방법의 성능을 평가, 비교하기 위하여 다수의 머신 러닝 데이터 집합에 적용한다.

• 한국지능시스템학회논문지
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• 제14권1호
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• pp.57-62
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• 2004

본 논문에서는 연결 성분간의 공간적 간격에 기반하여 수표 영상 내의 필기체 문장 금액에서 단어를 효율적으로 추출하기 위한 방법을 제안한다. 인접한 연결 성분간의 거리측정을 위한 기존의 방식들은 과대추정 또는 과소추정 문제로 인한 단어 분리 오류를 초래할 수 있으나 본 논문에서는 이러한 문제를 줄이기 위해 각 측정 방식들을 수정 보완하였다. 또한 본 논문에서는 서로 다른 형태의 세 가지 거리 측정법들을 효과적으로 결합하여 각 개별 측정법이 가지는 단점을 상호 보완하고 전체 단어 추출 성능을 좀더 향상시킬 수 있는 4-클래스 군집화에 기반한 결합 방법을 새로이 제안하였다. 분장 금액에 대한 단어 추출 실험 결과로부터 수정된 각 거리 측정법이 대응되는 기존의 측정법에 비해 2-3% 정도 향상된 단어 분리율을 보임을 확인하였다. 또한 제안된 4-클래스 군집화에 기반한 결합 방식은 각 측정 방식에서 개별적으로 발생하는 에러뿐만 아니라 두 개의 방식에서 동시에 나타나는 에러도 효율적으로 감소시킴으로서 전체 단어 분리 성능을 향상 시킬수 있었다.

• 조명전기설비학회논문지
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• 제22권10호
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• pp.56-61
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• 2008

배전계통의 고조파 방해(Harmonics Disturbance)현상은 배전계통에서 전압강하와 함께 순시 전력품질을 저해하여 중성선 및 NGR(Neutral Ground Reactor) 과열, OCGR 오동작 등의 문제를 발생시킴으로써 전력회사와 고객 모두에게 막대한 경제적인 손실을 주고 있어 동 분야에 대한 적극적인 대책이 필요하다. 이에 대한 해결 방안으로 유럽에서는 IEC 61000-3-2 규격을 통해 상당 16[A] 이하 저압 전기기기의 고조파를 제한하고 있다. 본 규격은 저압 전기기기를 4개의 등급으로 구분하여 관리하고 있으며, 분석결과 클래스 A등급 해당 전기기기의 고조파 유출제한 기준은 저압계통의 기준임피던스와 허용 최대전압을 바탕으로 산정되었으며, 타 등급(B, C, D등급)의 유출제한 기준들도 클래스 A의 유출제한 기준을 바탕으로 산정되었다. 따라서 본 논문에서는 IEC 61000-3-2 규격 분석결과를 바탕으로 국내 기준임피던스에 기초하여 국내 저압 전기기기의 고조파 유출 제한 값을 산정하였다.

• 대기
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• 제30권4호
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• pp.421-437
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• 2020

The effects of the terminal fall velocity-diameter relationship for raindrops, which is prescribed based on the measurement, on the simulated surface precipitation over Korea during summer season were investigated in our study. Two rainfall cases, 1-month summer precipitation and mesoscale rainfall, have been simulated using the Weather Research and Forecasting (WRF) model. The selected cloud microphysics parameterizations are WRF Single-Moment 5-class (WSM5) and WRF Single-Moment 6-class (WSM6) in the WRF model. The measured terminal fall-diameter relationship for raindrops by Gunn and Kinzer (1949) was applied in both WSM5 and WSM6. The sensitivity experiments with WSM5 and WSM6, applying the measured fall-diameter relationship, presents the different responses in simulated precipitation amount for the 1-month summer precipitation case. Precipitation increases with WSM5, thus enhancing the precipitation statistical skills. However, precipitation decreases with WSM6 leading to the deterioration of precipitation statistical skills. For the mesoscale rainfall case, precipitation increases with both WSM5 and WSM6, which further enhances the positive bias in precipitation amount.

• 대한한방내과학회지
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• 제43권2호
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• pp.244-253
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• 2022

Objective: This study reports on the management of a patient with myasthenia gravis (MG) following myasthenic crisis (MC) using Korean medicine. Methods: A 77-year-old Class V MG patient was treated with acupuncture, moxibustion, and Korean herbal medicine. A manual muscle test was used to derive a Medical Research Council (MRC) score and the patient's subjective view of his dyspnea was measured to assess MG symptoms. Results: The MRC grade indicated significant deterioration after 65 days of treatment, although there was no change in the patient's subjective dyspnea assessment. But no other MG or MC complications occurred. Conclusion: This study suggests that Korean medicine could be used for the management of Class V MG patients.

• 대한원격탐사학회지
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• 제8권1호
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• pp.27-43
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• 1992

The purpose of this study is to detect and evaluate the change of urban vegetation of Seoul during 1980s. Large areas covered with agricultural crops or forests were converted to residential and commercial areas, roads, schools, sports complexes, etc. There were also widespreas concerns on the deterioration of the quality of urban vegetation due to severe air pollution, overcrowding of nature parks, and idling of farm lands by land speculators. The image used for this study were MSS(Oct. 4, 1979) and TM(Apr. 26, 1990). The Green Vegetation Index of Kauth & Thomas(1976) was for the analysis. The GVI were resampled with 75$\times$75m grids and overlaid with the jurisdictional boundaries of 22 districts of Seoul. The results were reclassified to 6 classes, class 6 representing grids with the most vigorous vegetation or the best vegetation improvement in 1980s. The finding of this study can be summarized as follows : First, the most vigorous vigorous vegetation, in terms of GVI, of the 1979 image can be found at paddy fields located on alluvial near Han River. Broad-leaf forests located on hilly terrains have higher GVI than conifers located on the upper-parts of mountains. The average GVI of the northern part and southern part of Han River are 3.56 and 3.74, respectively. The main reason why the southern part has higher GVI is that there are more prime agricultural lands. Districts of Kangseo, Yangcheon, and Songpa have the highest percentage of grids of GVI class 6, and the percentages are 3.55 %, 3.47 %, and 2.69 %, respectively. Second, the most vigorous vegetation of the 1990 image can be found at the grass lands of the Yongsan golf club and the Sungsu horse racing track. The GVI of farm lands is lower than forest because most agricultural crops are at the early stage of growing season when the TM image was taken. The size of built-up area is much larger than of 1979. On the other hand, vegetation patches surrounded by developed area become smaller and have stronger contrast to surrounding area. The average GVI of the northern part and southern part of Han River are 3.57 and 3.51, respectively. The main reason why the southern part has lower GVI is the at more large-scale urban development projects were carried out in there during 1980s. Districts of Tobong, Nowon, and Seocho have the highest percentage of class 6, and the perecentages are 16.58 %, 10.14 %, and 8.50% respectively. Third, the change of urban vegetation in Seoul during 1980s are significant. Grids of GVI change classes 1 and 2, which represent severe vegetation loss, occupy 15.97% of Seoul. Three districts which lost the most vegetation are Yangcheon, Kangseo, and Songpa, where the percentages of GVI class 1 are 13.42%, 13.39% and 9.06%, respectively. The worst deterioration was mainly caused by residential developments. On the other hand, the vegetation of some part of Seoul improved in this period. Grids of GVI change classes 5 and 6 occupy 9.83 % of Seoul. Distircts of Jung, Yongsan, and Kangnam have the highest percentage of grids with GVI change classes 5 and 6, and their percentages are 22.31%, 19.17%, and 13.66%, respectively. The improvement of vegetation occurred in two areas. Forest vegetation is generally improving despite of concerns based on air pollution and heavy use by recreationists. Vegetation in open spaces established in riverside parks, large residential areas, and major public facilities are also improving.