이상치 분석을 통한 토석류 지반 모델링 신뢰성 분석

민대홍,박충화,윤형구 대한지질공학회 2016 대한지질공학회 학술발표회논문집 Vol.2016 No.1

토석류는 풍화 작용을 받아 퇴적된 토사층에 간극 수압이 증가하여 전단강도가 저하되거나, 우수의 침투와 상부 토층의 함수비 증가로 토층의 저항력보다 활동력이 증가하여 붕괴되는 현상이다(Iverson 1997). 기존에 보간법을 이용하여 토석류 사면에서의 토심, 고도, 그리고 경사도를 모델링한 연구 결과가 존재하나, 표본자료의 이상치에 대한 분석 없이 보간법을 실시하여 신뢰성이 검증되지 않았다. 본 연구에서는 토석류 위험 사면에서 탄성파 탐사를 통해 도출된 표토층 두께를 보간법의 표본자료로 이용하였으며, 이상치 분석을 통해 표본자료의 이상치를 제거후 보간법을 실시하였다. 탄성파 탐사 위치는 세종시 괴화산 계곡부로서 과거 토석류가 발생된 위험지역에서 실시하였다. 탄성파 측선은 계곡부 중심으로 총 4개로 설정하였으며, 수신기의 간격은 2m로 설정하였다. 사용된 탄성파 장비는 Geometric사의 GEODE를 사용하였으며, 인공 파형은 Hammer와 Plate를 이용하였다. 탄성파 결과 0.5km/s 속도를 보이는 표토층 두께는 사면의 하부는 1.8m, 중부는 0.6m 그리고 상부는 4.4m를 보였다. 도출된 표토층 두께는 2m 간격으로 데이터를 획득하여 보간법의 표본자료로 사용하였다. 이상치 분석 방법 중 GEV(Generalize Extreme Value) 방법과 교차 검증을 통한 오차율을 이용하여 표본자료에서의 이상치 제거 범위를 설정하였으며, 그 결과 오차율은 .94%~42% 그리고 표토층 두께는 0.6m~4.5m 범위 밖에 해당되는 이상치를 제거하였다. 이상치가 제거된 표본자료를 기반으로 Kriging 기법을 이용하여 토석류 위험 지역의 표토층 두께를 모델링하였으며, 사면의 상부는 표토층 두께가 평균적으로 4m 이상의 두터운 지층으로 나타났으며, 하부는 평균적으로 1m 이하의 얇은 표토층으로 나타났다. 최종적으로 본 연구를 통하여 토석류 위험 지역 모델링에 사용되는 보간법의 신뢰성을 증가시킬 수 있을 것으로 판단된다.

안토시아닌의 항산화 활성 증진을 위한 후코이단 기반의 나노이온복합체

민대홍,나건 한국생체재료학회 2012 생체재료학회지 Vol.16 No.2

To improve the antioxidant efficiency of anthocyanin, fucoidan-anthocyanin nanocomplex has been investigated. The nanocomplex was fabricated by simple process in water phase to minimize loss of anthocyanin. In the nanocomplex,structure of anthocyanin was changed from flavylium cation to quinoidal base structure. Between 200 to 300 nm of spherical nanocomplex was observed by dynamic light scattering (DLS) and field emission scanning electron microscopy (FE-SEM). The nanocomplex has 10 fold lower critical assemble concentration (CAC) value (0.025 mg/ml) than free anthocyanin (0.25 mg/ml). The radical scavenging rate of anthocyanin against DPPH radicals and hydrogen peroxide were improved from 76% to 79% and from 20% to 60%, respectively. Finally, anticancer activity of anthocyanin was measured to estimate the in vitro radical scavenging activity. In the lipopolysaccharide (LPS) mediated reactive oxygen species (ROS) rich condition, the nanocomplex effectively reduced cancer cells viability (77%) to compared with free anthocyanin (121%). Therefore, we conclude that fucoidan-anthocyanin nanocomplex has a potential for use as a carrier for anthocyanin delivery. These nanocomplexes would prove useful application in the food, beverage and pharmaceutical industries.

도로확장으로 차량하중을 받게 된 지중암거 보강공사 시공사례

민대홍 한국도로학회 2016 한국도로학회지 Vol.18 No.4

국가 재난으로서의 신종 바이러스의 진화와 위기 관리

민대홍 대한안전경영과학회 2021 대한안전경영과학회 학술대회논문집 Vol.2021 No.10

합성곱 신경망 모델 기반의 폐기물 분류 시스템 연구

민대홍,곽민구,김성범 대한산업공학회 2019 대한산업공학회 추계학술대회논문집 Vol.2019 No.11

성형수술 환자들의 정신의학적 측면에 관한 연구(I)

안재훈,김승홍,이영식,한상준,이철원,백무현,민대홍 大韓成形外科學會 1991 Archives of Plastic Surgery Vol.18 No.6

The psychological problem in patients of plastic and reconstructive surgery is important for the decision of operability. In order to evaluate the psychological aspect of a patient, we analyzed 102 patients who agreed to Co-operate in our study. They were devided into three groups as aesthetic group(GroupⅠn=27), reconstructive group(GroupⅡ n=49) and acute trauma group(GroupⅢ n=26;controls) with Korean standadized MMPI from June,1990 to November,1990 in our hospital. The results of this study are as follows: 1) Un-married females of third decade of life are numerically dominant. 2) The most prevalent operation site is exposed face area. 3) The analysis of profile in clinical scale reveals that most patients of abnormal finding had neurotic tendency and personality problems.

글루타알데하이드로 처리한 동종연골이식의 실험적 연구

한상준,백무현,김승한,김승홍,민대홍 大韓成形外科學會 1991 Archives of Plastic Surgery Vol.18 No.4

Reconstruction of the ear is a difficult problem in plastic surgery and there is still no ideal material to reconstruct ear cartilage. Recently glutaraldehyde treatment have been shown to decrease the antigenecity and break-down of graft material. Herein we performed an experimental comparative study of glutaraldehyde-treated homogenous graft, and glutaraldehyde untreated homogenous graft and autogenous graft of ear cartilage in rabbits. Degree of foreign body inflammatory reaction, capsular formation, and weight reduction of ear cartilage grafts were analyzed in each group at 1st week, 4th week, and 6th week. Glutaraldehyde treated homogenous ear cartilage graft showed less foreign body reaction and weight reduction than glutaraldehyde untreated homogenous ear cartilage graft and were well preserved in shape. Glutaraldehyde treated homogenous ear cartilage grafts were comparable to autogenous grafts. We conclude that glutaraldehyde treated homogenous cartilage is a highly promising graft material for the reconstruction of ear. We might expect that glutaraldehyde treated cadeveric cartilage can be used in the reconstruction of ear.

Improvement of crystal quality and optical property in [11-22] semipolar InGaN/GaN light emitting diodes grown on hemi-spherically patterned SiO2 mask

민대홍,유근호,유영우,문승환,이규호,남옥현 한양대학교 세라믹연구소 2013 Journal of Ceramic Processing Research Vol.14 No.4

We report the improved crystal quality and optical property in (11-22) semipolar InGaN/GaN light emitting diodes (LEDs) grown on hemi-spherically patterned SiO2 mask on m-plane sapphire substrate (HP-SiO2) compared with the m-plane sapphire substrate (m-planar), using metalorganic chemical vapor deposition (MOCVD). The photoluminescence (PL) results showed that the integrated intensity of the near band edge (NBE) emission of the GaN layer grown on HP-SiO2 was increased by 3 times as high as that of m-planar. The full width at half maximums (FWHMs) of X-ray rocking curves for the on- and off-axis planes of the GaN layers on HP-SiO2 were narrower down than on m-planar, which indicates that the crystal quality of the semipolar GaN layers on HP-SiO2 was considerably improved as compared with that on m-planar by reducing defects such as perfect/partial dislocations and basal stacking faults. Cross- sectional transmission electron microscopy (TEM) images also showed the reduction of dislocation density in GaN layers on HP-SiO2 than on m-planar. The optical power of InGaN/GaN LEDs with HP-SiO2 was increased by 1.7 and 7.3 times at injection current of 20 mA and 100 mA, respectively, in comparison with the m-planar LEDs.

외측 상박부 유리 근막 피판을 이용한 사지 연부 조직 결손부의 피복

김승홍,박정준,곽혁준,최병욱,민대홍 大韓成形外科學會 1996 Archives of Plastic Surgery Vol.23 No.4

Traumatic injury to the hand or foot often leads to extensive skin and soft tissue loss, exposing the blood vessels, nerves, tendons or bones. Therapeutic options for salvaging these soft tissue defects include local, regional or distant flaps and free flap transplantation. Over the last two decades, the use of free tissue transfer has gained increasing popularity in reconstruction of soft tissues defect. Reconstruction of soft tissue defects with exposure of bone, tendon or other vital structures on the hands and feet can be a challenging problem, especially open wounds on dorsum of the foot and hand. The main purposes of resurfacing of the soft tissue defects are early coverage and mobilization of the defects to cover the exposed vital structures and to prevent further deformity. In hand and foot dorsum resurfacing, the fascia is the most ideal donor flaps in terms of thin, pliable and well vascularized sheets of tissue. It leaves an inconspicuous donor site morbidity. In addition, microvascular transfer is facilitated the axial pattern flap with consist, reliable vascular pedicles. The flap is useful in covering exposed bone and tendon without unwanted bulk, in providing an ultrathin flap coverage in soft tissue defects, and it provides a good intrinsic blood supply to improve local conditions for healing and to decrease bacterial contamination of the wound. It can also establish a fine tendon-gliding mechanism. We have experienced 8 cases of resurfacing of full thickness skin and soft tissue loss in the hand and foot dorsum defects with lateral arm fascia free flap. We achieved successfully soft tissue coverage with minimal complications. The largest size of the flap had 13.5×9cm in dimesion. We could gain satisfactory results of soft tissue coverage with ultrathin arterialized pedicale flap and now we report our clinical experience of lateral arm fascia free flap.

조직확장기를 이용한 상안검 피부이식부위의 축소술

이인섭,김재덕,백무현,김승홍,민대홍 大韓成形外科學會 1990 Archives of Plastic Surgery Vol.17 No.6

In the upper eyelid,the large skin defect that cannot be repaired primarily is usually coverde with skin graft. But the rigidity of the grafted full thickness skin make the superior palpebral fold at the higher level along the upper margin of the graft than the opposite side. In this paper,we would like to correct this asymmetry by using tissue expander. Nowadays,the tissue expander became the one of the most popular technique in the field of plastic and reconstructive surgery since it was introduced in 1976 by Rodovan. Althogh numerous reports on both the clinical and experimental experiences have been advocated, there still remain certain problems on its accurate indication and standard techniques for promising good results. Futhermore, the clinical application of tissue expander on the upper eyelid was seldom introduced. To insert the prosthesis, the skin incision was made just beneath the upper margin of the grafted skin. The prosthesis was placed under the muscle layer in oder to decrease the risk of implant exposure and then reservoir dome was placed in ipsilateral temporal area. Two weeks after prosthesis placement, the serial inflation was made by small amount and short interval for 3 weeks(0.3-0.4cc/time,2 times/week)to avoid eyeball compression. After adequate expansion was completed,the expander was removed.The grafted skin was excised to the same level of the opposite normal fold and the expanded normal skin above the grafted skin was advanced inferiorly. And then the graft area was confined below the normal height of palpebral fold. Therefore, the asymmetry of both upper eyelid was corrected satisfactorily.