• Korean Journal of Oriental Medicine
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• v.10 no.2
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• pp.73-78
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• 2004

Purpose : The aim of this study was to investigate correlation between retention of fluid and PWV/ABI. Methods : The sample consists of 35 women who took plethynography(VS-1000;Fukuda Co.Ltd, Japan) at Oriental medicine exhibition held in COEX mall from August. 26. 2004 to August. 29. 2004. They were asked the intensity of the symptoms like dizziness or headache, nausea or bowel trouble, coldness in knee, and palpitation(1:none, 2:a little, 3:mild, 4:moderate, 5:severe). Women who answered 1,2 were classified as control group, and women who answered 3,4,5 were experimental group. Result : There was stastically significant correlation between dizziness and ABI Conclusion : It is believed that ABI may be the favorable alternative to the diagnosis of dizziness or headache.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1595-1600
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• 2004

When a shock wave arrives at a duct, an impulsive wave is discharged from the duct exit and causes serious noise and vibration problems. In the current study, the characteristics of the impulsive wave discharged from a partial closed duct exit is numerically investigated using a CFD method. The Yee-Roe- Davis's total variation diminishing(TVD) scheme is used to solve the axisymmetric, unsteady, compressible Euler equations. With several partial closed duct exits, the Mach number of the incident shock wave $M_s$ and the distance L/D between the duct exit and a flat plate are varied in the range of $M_s$ = 1.01 ${\sim}$ 1.50 and L/D = 1.0 ${\sim}$ 4.0, respectively. The results obtained show that the magnitude of the impulsive wave impinging upon the flat plate strongly depends upon $M_s$, L/D and the partial closure of duct exit. The impulsive wave on the flat plate can be considerably alleviated by the partial closure of duct exit and, thus, the present method can be a passive control for the impulsive wave.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.201-204
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• 2006

The shear resistance of RC beams is subject to the amount of shear-reinforcing bars ($p_w$) and yield strength ($f_{wy}$) as well as their interactive influence ($p_wf_{wy}$). Thus, it is reasonably expected that high-strength steel bars can greatly reduce the necessary amount of shear-reinforcing bars. On the other hand, although the bond strength is influenced by the amount of shear reinforcing bars, it is not affected by the yield strength. Thus, there is often an issue that bond failure occurs before shear failure depending on the arrangement of shear reinforcing bars. It is a common practice to set sub-ties for the transverse confinement of the main re-bars as a method to prevent the bond failure. However, it can also become a factor in decreased work efficiency due to the complexity of the construction. This study experimented with simultaneous use of high-strength transverse reinforcing bars ($f_{wy}=800MPa$) and U-shaped transverse reinforcing bars of regular strength ($f_{wy}=300MPa$) in an attempt to decrease the necessary quantity of shear reinforcing bars. The effect of this attempt was investigated through fundamental experimental research in terms of the improvement in shear resistance and bond strength as well as the ease of construction.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.638-638
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• 2012

인구증가와 한정된 물 공급에 따른 하천과 생태계 관리는 의사결정자들의 복잡한 문제이다. 하천 시스템에 대한 우리의 이해 능력은 기술과 과학적 이해 모두 향상되어가고 있다. 자료 모형, 예측 모형 등은 수십 년간 하천 관리 시스템과 유출 등을 예측하는데 사용되었다. 하천 생태계 프로세스에 대한 지식과 더 정확하게 증가된 자료의 수집 능력으로 인해 풍부한 자료를 갖게 되었다. 특히 4대강 사업에 따른 하천환경 변화로 하천관련 정보가 과거에 비해 비약적으로 증가하고 있어 이를 효율적으로 관리하는 이용체계 수립이 필요하다. 현재 하천 시스템은 국가, 지자체, 연구기관 등 공급자 중심으로 운영되고 있다. 따라서 국가차원에서 방대한 자료와 IT/NT/BT의 융복합적 첨단기술을 접목한 하천 시스템 구축에 대한 대책이 필요할 것이다. 이를 국외 하천 정보화 사례들을 통해 실시간으로 관측되고 있는 자료와 하천 시스템을 살펴보고 우리나라가 가야할 방향에 대해 알아보고자 한다. 선진 정보화 시스템은 정부, R&D, 지자체가 각 시스템을 개발하고 함께 자료를 공유하는 통합시스템을 지향하고 있다. 미국과학재단의 펀드로 정부, 대학, 지자체가 함께 수문 자료 시스템과 수질환경 자료 시스템을 개발하고 이를 통합수문환경정보시스템으로 발전시키고 있다. 우리나라 정보화 시스템의 경우 정부 시스템은 공개 되어 있지만. R&D 시스템은 폐쇄적이다. 또한 각 주정부부처의 개별 시스템은 구축이 되어있지만 수문, 환경이 통합된 정보시스템은 미비한 실정이다. 앞으로 시험유역의 체계적 정보취합과 분석 자료의 시스템 구축 및 공유가 필요할 것으로 사료된다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.273-275
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• 2021

본 논문에서는 기존 스마트주차관제 시스템의 한계로 인해 주차 관제의 사각지대에 있는 다세대 주택 주차 문제를 해결하는 솔루션을 제안한다. 기존 스마트 주차관제는 센서 기반의 고비용의 장비 및 시공비가 소요되며, 이러한 특성으로 인해 다세대 주택에 적용이 어렵다. 해당 문제를 해결하기 위해 본 논문은 기존 설비인 CCTV를 활용한 스마트 주차 관제 시스템을 제안하며, 해당 솔루션은 텐서플로 cnn중 알씨엔엔 RPN을 적용하여 차량 객체 인식 및 주차 공간 객체 인식을 구현하였으며, 다세대 주택 주변 CCTV 영상을 OpenCV를 활용하여 능동적이며 저비용의 스마트 주차 관제 방식을 구현하였으며 CCTV의 특성상 외곡되는 이미지를 OpenCV 이미지 변형을 통해 외곡 이미지를 복원하여 인식률을 높였다.

• Journal of Chest Surgery
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• v.36 no.7
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• pp.463-471
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• 2003

The long-term results of combined mitral valve repair and aortic valve replacement (AVR) have not been well evaluated. This study was performed to investigate the early and long-term results of mitral valve repair with AVR. Material and Method: We retrospectively reviewed 45 patients who underwent mitral valve repair and AVR between September 1990 and April 2002. The average age was 47 years: 28 were men and 17 women. Twelve patients had atrial fibrillation and three had a previous cardiac operation. The mitral valve disease consisted of pure insufficiency (MR) in 34 patients, mitral stenosis (MS) in 3, and mixed lesion in 8. Mitral valve disease was due to rheumatic origin in 24 patients, degenerative in 11, annular dilatation in 8, and ischemia or endocarditis in 2. The functional anatomy of mitral valve was annular dilatation in 31 patients, chordal elongation in 19, leaflet thickening in 19, commissural fusion in 13, chordal fusion in 10, chordal rupture in 6, and so on. Aortic prostheses used included mechanical valve in 32 patients, tissue valve in 12, and pulmonary autograft in one. The techniques of mitral valve repair included annuloplasty in 32 patients and various valvuloplasty of 54 techniques in 29 patients. Total cardiopulmonary bypass and aortic cross clamp time were 204$\pm$62 minute and 153$\pm$57 minutes, respectively. Result: Early death was in one patient due to low output syndrome (2.2%). After follow up of 57$\pm$37 months, late death was in one patient and the actuarial survival at 10 years was 96$\pm$4%. Recurrent MR developed grade II or III in 11 patients and moderate MS in 3. Three patients required reoperation for valve-related complications. The actuarial freedom from recurrent MR, MS, and reoperation were 64$\pm$11%, 86$\pm$8%, and 89$\pm$7% respectively. Conclusion: Combined mitral valve repair with AVR offers good early and long-term survival, and adequate techniques and selection of indication of mitral valve repair, especially in rheumatic disease, are prerequisites for better long-term results.

• Radiation Oncology Journal
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• v.17 no.3
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• pp.209-216
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• 1999

Purpose : To evaluate the effectiveness of external radiation therapy and the prognostic factors, we retrospectively analyzed therapeutic results of malignant extrahepatic biliary obstruction (EHBO). Methods and Materials : We analyzed the results of the external radiation therapy in 59 patients of inoperable malignant EHBO who had been treated with more than 10 Gy of external radiation therapy from April 1984 to December 1990. There were 21 stomach cancer ($35.6\%$), 12 pancreas cancer ($20.3\%$), 15 extrahepatic biliary cancer ($18.0\%$) and 11 another cancer ($18.0\%$). Their pathologies were confirmed in 31 patients ($52.5\%$). They divided into 27 adenocarcinoma and 4 nonadenocarcinoma. Their chief complaints were jaundice in 47 patients ($79.7\%$) and abdominal pain in 15 patients ($49.2\%$). Twelve patients had slightly increased bilirubin level in liver function test without jaundice. We treated twenty four patients ($40.6\%$) with percutaneous transhepatic biliary drainage (PTBD) and 32 patients ($54\%$) with systemic chemotherapy (CT). We performed external radiation therapy (ERT) upto $10.8\~55.8$ Gy (median 37.8 Gy) with palliative aim. Results : Overall median survival duration was $7.80\pm1.15$ months. The response rates of jaundice were $81.8\%$ in PTBO group and $66.7\%$ in non-PTBD group without statistical significance. The improving rate of jaundice was not significantly different in decreased ratio of total bilirubin level. But abdominal pain was more decreased in CT group than non-CT group (p<0.05). The significant prognostic factors were high performance status (Karnofski Performance Status >70), total radiation dose more than 35 Gy and good response of pain after therapy. There were increased in bacterial cholagitis in PTBD group and gastrointestinal complications in CT group. Conclusion : External radiotheapy could improve jaundice and abdominal pain in malignant EHBO patients, Overall survival duration was prolonged in patients with higher performance status and patients who had been treated with more than 35 Gy of total radiation dose. In the future, we expect not only better palliative role but also the prolongation of survival of using the ERT combined with other treatment method. But to achieve certain conclusion, we need luther study consisted with many kinds of treatment methods including new technologies in RT.

• Geophysics and Geophysical Exploration
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• v.13 no.1
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• pp.96-101
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• 2010

A pulse radar system has been developed recently to detect dormant underground tunnels that are deeply located at depths of hundreds of metres. To check the ability of the radar system to detect an obliquely oriented tunnel, five different borehole pairs in the tunnel test site were chosen so that the horizontal lines-of-sight cut the tunnel axis obliquely, in $15^{\circ}$ steps. The pulse radar signatures were measured over a depth range of 20 m around the centre of the air-filled tunnel. Three canonical parameters, consisting of the arrival time, attenuation, and dispersion time were extracted from the first and second peaks of the measured radar signatures. Using those parameters, the radar system can detect obliquely oriented tunnels at various angles up to 45 from the transmitter-receiver line of sight.

• Journal of the Korean earth science society
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• v.28 no.3
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• pp.357-366
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• 2007

In Gomso Bay, on the west coast of Korea, the surface sediments sampled in 1991 and 2006 were analysed to identify the long-term variations of tidal flat sediments. Silt and clay contents have decreased in the bay-mouth tidal flats whereas sand and clay contents have decreased on the inner-bay and bay-head tidal flats over the last 15 year period. In particular, the clay contents of the tidal flats in 2006 were relatively low when compared to those of both tidal flats adjacent to other semi-enclosed bays and those of the tidal flats in 1991. The variations of textural compositions in the tidal flat sediments have led to changes of the sedimentary facies. It indicates that the changes must have been made by the changes of hydrodynamic conditions impacted by human activities, such as the construction of sea-walls, land reclamation, structures of farms constructed compactly near the low water line, and the Saemangeum dyke constructed in the northern part of the area where this research was conducted.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.159-162
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• 2008

In this study, various cycles of liquid rocket engines were surveyed and specifically gas generator after burning cycle was investigated for upper stage motors. The engines for the upper stage can be categorized into three group based on the cycles and propellants at the diagram. Kerosene engines which adapt the gas generator after burning cycle and are located in the region II, are characterized for high combustion pressure and complexity. This cycle usually needs more than two pumps to use the turbine power efficiently. The fuel line can be divided into the gas generator line and the combustor line, and only the gas generator line is need to be pressured more because the combustion pressure in the gas generator is much higher than that of the combustor. Basically, all the oxidizer goes into the gas generator and than to the combustor, thus the auxiliary LOx pump is not critically necessary. However, for the various reasons, the LOx line requires a booster pump. A gas generator after burning cycle engines produces relatively high specific impuls than that of the open cycle engines. Thus it is suitable for upper stages of launch vehicles.