Modeling of the Tensile Strength of Unsaturated Granular Soil Using Soil-water Characteristic Curve

김태형,김찬기,김태훈,Kim Tae-Hyung,Kim Chan-Kee,Kim Tae-Hoon Korean Geotechnical Society 2004 한국지반공학회논문집 Vol.20 No.7

본 연구는 불포화 상태 전 범위에 대한 사질토의 인장강도 모델화 가능성을 조사하기 위해 실시 되었다. 새로 개발된 직접인장시험기법을 이용하여 인장시험이 실시되었다. 측정된 결과는 Rumpf 및 Schubert가 동일크기의 이상적인 구에 대해 개발한 이론적인 인장강도 모델들에 의한 예측 값과 비교 되었다. 이를 위해 석션-포화실험을 통해 얻어진 흙-수분특성곡선을 이용하여 이론모델에 있어 중요한 요소인 불포화상태(pendular, funicular, capillary) 구분 및 음의 간극수압 값을 산정하는데 사용하였다. Pendular 상태에서 불포화모래의 비선형 거동이 Rumpf의 모델에 의해 적절이 묘사되었다. Funicular 및 capillary상태의 경우, 함수비가 증가함에 따라 인장강도가 증가하다 최고 값이 도달한 후 다시 감소하는 실험 측정치의 경향도 Schubert의 모델에 의해 적절히 묘사되었다. 본 비교 연구는 이상적인 단일 크기의 입자에 대해 개발된 이론적인 모델이 다양한 크기를 갖는 불포화 사질토의 인장강도를 예측할 수 있다는 가능성을 뒷받침해준다. This study was conducted to explore the tensile strength models in granular soil at the full range of unsaturated state. Direct tension experiments were carried out with a newly developed direct tension technique. The measured experimental data were compared with theoretical models developed by Rumpf and Schubert for monosized ideal particulate solids at the unsaturated state. To do this, the soil-water characteristic curve obtained from a suction-saturation experiment was used to define the unsaturation state and the negative pore water pressure with different water content levels, which are important factors in theoretical tensile strength models. The nonlinear behavior of the tensile strength for unsaturated granular soil at the pendular state is appropriately simulated with Rumpf's model. For the funicular and capillary states, the predicted trend by Schubert's model is properly matched with the experimental data: tensile strength steadily increases and reaches a maximum value and then decreases until it reaches zero. This comparison supports the concept that the tensile strength of unsaturated real granular soil can be approximately simulated with theoretical models.

편측 신장 무형성 및 쇄항을 동반한 Mayer-Rokitansky-Kuster-Hauser(MRKH) 증후군 1례

김태형,김진희,김수영,Kim, Tae-Hyung,Kim, Jin-Hee,Kim, Soo-Yung 대한소아신장학회 2006 Childhood kidney diseases Vol.10 No.2

MRKH 증후군은 비뇨생식기계 및 골격계에 기형을 동반하지만 쇄항에 대한 동반 기형유무 검사상에서 MRKH 증후군으로 진단된 경우는 거의 보고되고 있지 않다. 이에 저자들은 쇄항을 주소로 내원한 34주 미숙아에서 MRKH 증후군으로 진단된 본 증례를 경험하였기에 문헌고찰과 함께 보고하는 바이다. The clinical features of the Mayer-Rokitansky-K$\ddot{u}$ster-Hauser(MRKH) syndrome include normal female secondary sex characteristics, normal genitalia, congenital absence of vagina, rudimentary or bipartite uterus, normal ovarian function and normal ovulation, 46, XX, karyotype, frequent association of renal, skeletal and other congenital anomalies. We experienced a case of a premature infant with MRKH syndrome who had imperforate anus and unilateral renal agenesis.

반사형 쌍안정 카이랄 스플레이 네마틱 액정표시소자

김태형,이중하,신정국,장지향,김정수,전철규,권순범,윤태훈,김재창,Kim, Tae-Hyung,Lee, Joong-Ha,Shen, Zheng-Guo,Jang, Ji-Hyang,Kim, Jeong-Soo,Jhun, Chul-Gyu,Kwon, Soon-Bum,Yoon, Tae-Hoon,Kim, Jae-Chang 한국광학회 2011 한국광학회지 Vol.22 No.1

쌍안정 카이랄 스플레이 네마틱 액정표시소자는 스플레이 상태와 $-\pi$ 꼬인 상태를 쌍안정 상태로 사용하는 메모리 액정표시소자이다. 셀 갭/피치의 값이 0.25일 경우 완전한 쌍안정 상태를 갖지만, $-\pi$ 꼬인 상태에서 스플레이 상태로 전이시키기 위하여 fringe 전계를 인가할 경우 픽셀영역은 전계의 왜곡에 의해서 완전한 스플레이 상태가 아니라 $-\pi$ 꼬인 상태를 부분적으로 유지하게 된다. 본 논문에서는 화소영역에서 두 안정한 상태가 공존하지 않는 $-\pi$ 꼬인 상태를 어두운 상태로 사용하는 반사형 쌍안정 카이랄 스플레이 네마틱 액정표시소자를 제안한다. 제작된 반사형 액정표시소자는 30:1의 고명암비를 나타냈으며, 응답속도는 수직전압 8 V, fringe 전압 12 V의 구동 전압으로 각각 쓰기 응답시간이 950 ms, 리셋 응답시간이 450 ms였다. 또한 제안된 셀은 +C 광학 보상 필름을 사용하여 좌우 방향에서 $180^{\circ}$의 광시야각을 나타냈다. Bistable chiral splay nematic liquid crystal display (BCSN LCD) is a memory type liquid crystal display using splay and $-\pi$ twist states as two stable states. When the cell thickness to pitch (d/p) ratio is 0.25, splay and $-\pi$ twist states have permanent memory time. However, when the transition from $-\pi$ twist state to splay state is caused by a fringe field, pixel regions show that the splay state is not perfect, but rather includes a contribution from the $-\pi$ twist state. In this paper, we propose a reflective BCSN LCD using $-\pi$ twist state in which the two stable states do not coexist. The fabricated reflective BCSN LC cell shows a high contrast ratio of over 30:1 and response times of 950 ms and 450 ms in vertical and fringe field switching, respectively. The proposed cell also shows wide viewing angle characteristics of $180^{\circ}$ in left- and right directions.

김중업의 「경주 석굴암 보수공사 설계」(1961-1962)에 관한 고찰

우동선,김태형,Woo, Don-Son,Kim, Tae-hyung 한국건축역사학회 2021 건축역사연구 Vol.30 No.4

This study examines the Gyeongju Seokguram Grotto restoration project (1961-1962) by architect Kim Chung Up (1922-1988) and introduces the documents he wrote at the time of planning. The study highlights Kim's Plan attempt to adopt Buckminster Fuller's idea of the Geodesic Dome, while inheriting the architect Pai Ki Hyung's previous design plan which was nullified. As Seokguram Grotto's water leak and deterioration issues have been brought up, the four-times survey was carried out by experts team between 1958 and 1960, under Ministry of Education's direction. Pai designed an initial restoration plan based on the survey's result, which was a double-dome structure with a concrete film on the outer periphery as a way to protect Seokguram Grotto in January 1961. However, as drawbacks, such as the heavy load of the concrete dome, and non-installation of entrance hall, have been indicated in the review process, the Cultural Properties Committee rejected the plan. Subsequently, Kim was appointed as the supervisor of the second restoration project. Kim drew up a process management schedule to be implemented from August 1961 to December 1963 and designed the conception plans for the second restoration design. This study analyzes Kim's Plan by examining sketches, site plans, floor plans, and sections. Kim planned to maintain the idea of the double-dome structure proposed by Pai while applying Buckminster Fuller's idea of the Geodesic Dome. Kim planned to lighten the dome structure by applying a steel-frame Geodesic Dome so that the dome structure could be supported by its own. The study is expected to reclaim the omitted parts from Seokguram Grotto's historical description and Kim's careers.

신경회로망과 다중스케일 Bayesian 영상 분할 기법을 이용한 결 분할

김태형,엄일규,김유신,Kim Tae-Hyung,Eom Il-Kyu,Kim Yoo-Shin 대한전자공학회 2005 電子工學會論文誌-SP (Signal processing) Vol.42 No.4

This paper proposes novel texture segmentation method using Bayesian estimation method and neural networks. We use multi-scale wavelet coefficients and the context information of neighboring wavelets coefficients as the input of networks. The output of neural networks is modeled as a posterior probability. The context information is obtained by HMT(Hidden Markov Tree) model. This proposed segmentation method shows better performance than ML(Maximum Likelihood) segmentation using HMT model. And post-processed texture segmentation results as using multi-scale Bayesian image segmentation technique called HMTseg in each segmentation by HMT and the proposed method also show that the proposed method is superior to the method using HMT. 본 논문에서는 Bayesian 추정법과 신경회로망을 이용한 새로운 결 분할 방법을 제안한다 신경회로망의 입력으로는 다중스케일을 가지는 웨이블릿 계수와 인접한 이웃 웨이블릿 계수들의 문맥정보를 사용하고, 신경회로망의 출력을 사후 확률로 모델링한다. 문맥정보는 HMT(Hidden Markov Tree) 모델을 이용하여 구한다. 제안 방법은 HMT를 이용한 ML(Maximum Likelihood) 분할 보다 더 우수한 결과를 보여준다. 또한 HMT를 이용한 결 분할 방법과 제안 방법을 이용한 결 분할 각각에 HMTseg라고 불리는 다중 스케일 Bayesian 영상 분할 기술을 이용하여 후처리를 행한 결 분할 또한 제안 방법이 우수함을 보여준다.

생쥐와 인간배아의 완만동결-급속융해 후 생존률과 배아발생에 미치는 Ethylene Glycol (EG)과 1,2-Propanediol (PROH)의 영향

김태형,차수경,이동률,한지은,이우식,윤태기,차광렬,정형민,Kim, Tae-Hyung,Cha, Soo-Kyung,Lee, Dong-Ryul,Han, Jee-Eun,Lee, Woo-Sik,Yoon, Tai-Ki,Cha, Kwang-Yul,Chung, Hyung-Min 대한생식의학회 2004 Clinical and Experimental Reproductive Medicine Vol.31 No.1

Objective: The aim of this study were to compare the effects of EG and PROH on cryopreservation of mouse and human embryos, and to find the optimal protocol for embryo freezing. Methods: Human embryos derived from fertilized eggs showing 3 pronuclei (PN) and mouse embryos were divided into two groups respectively: dehydrated with 1.5 M EG + 0.2 M sucrose or 1.5 M PROH + 0.2 M sucrose using the slow freezing method. Moreover mouse embryos were controlled the exposure time of cryoprotectant during dehydration or rehydration steps. Results: The survival rates of human embryos were 79.2% (84/106) in EG group and 77.9% (88/113) in PROH group. In mouse embryos, the survival and development rates up to blastocyst were 70.6% (245/347), 44.1% (123/279) in EG group and 62.1% (198/319), 45.1% (123/279) in PROH group, respectively. However, in EG group, partially damaged embryos after thawing were decreased compared to PROH group. In combination group, when the exposure time during dehydration and rehydration were reduced, the survival and embryonic developments were increased slightly, but not significant. Conclusion: Cryopreservation of mouse and human embryos at cleavage stage by using EG or PROH exhibited no statistical difference in the survival rate and/or developmental rate to blastocyst. However, the use of EG for cryopreservation of embryos might reduce the exposure time of the cryoprotectant because of a high permeation of EG and result in lessen its toxic effects.

Mecrostrip Array Antenna Directly Coupled to E-Plane

김태형,홍재표,박진택,조영기,손현,Kim, Tae-Hyung,Hong, Jae-Pyo,Pak, Chin-Taek,Cho, Young-Ki,Son, Hyon The Institute of Electronics and Information Engin 1991 전자공학회논문지-A Vol.28 No.1

In order to improve the radiation characteristics of the microstrip antenna, microstrip array antenna consisting of one center patch fed by a coaxial probe and several patches directly coupled to the E-plane by microstrip line is analyzed. The equivalent circuit of the array antenna is represented by the conventional transmission line and the various parameters, such as the mdicrostrip line length, the patch length and the feed point location are calculated to improve the radiation pattern for 5-patch array antenna which has the equal patch width. The 5-patch array antenna with the radiation pattern which has low sidelobe level and narrow beam width is fabricated and then the measured results are compared with the computed values and the results of the single patch microstrip antenna too.

연골판 이식술의 적응증과 수술 전 계획

김태형,최남홍,Kim, Tae-Hyung,Choi, Nam-Hong 대한관절경학회 2011 대한관절경학회지 Vol.15 No.1

연골판 절제술로 인한 슬관절의 퇴행성 변화와 이로 인한 임상적 증상을 예방하기 위해 연골판의 기능을 수복할 동종 연골판 이식술이 필요하다. 환자들에게 만성 전방십자인대 파열이나, 연골 손상, 내반 변형 등 동반되는 상황이 있을 수 있으므로 이에 대한 적절한 수술 전 준비가 필요하고, 동종 연골판 이식술 후 좋은 결과를 얻기 위해 적절한 환자의 선택이 중요하다. Meniscal allograft transplantation is considered to restore important functions of the meniscus after total and subtotal meniscectomy. There are patients who need meniscal allograft transplantation have concomitant lesions; chronic anterior cruciate ligament tear, chondral defect, and malalignment of the knee. Therefore proper selection of the patients and thorough preparation of operative procedure are imperative to get satisfactory results.

스터럽 보강 선설치 앵커의 지진모의실험에 의한 동적 전단 저항강도 평가

김태형,박용명,강충현,이종한,Kim, Tae Hyung,Park, Yong Myung,Kang, Choong Hyun,Lee, Jong Han 한국강구조학회 2018 韓國鋼構造學會 論文集 Vol.30 No.2

스터럽 보강 선설치 앵커의 동적 전단하중 하의 파열파괴강도를 평가하기 위한 실험 연구를 수행하였다. 전단 하중은 ACI 355.2 및 ETAG 001에 제시된 지진모의실험 방식으로 재하하였다. 시험체는 M36 앵커(연단거리 180mm)를 D10 스터럽(간격 100mm)으로 보강하였다. 이들 시험체는 거의 극한 파열파괴 강도에 도달한 후 앵커의 파단이 발생하였다. 이에 M42 앵커(연단거리 160mm)를 D6 스터럽(간격 100mm)으로 보강한 시험체에 대한 실험을 추가로 수행하였다. 실험 결과, 동적 전단강도는 정적 강도에 비해 낮은 값을 보이지 않았다. 또한, ACI 318 및 ETAG 001 기준은 스터럽 보강이 많을수록 파열파괴강도를 안전측으로 평가하는 것으로 나타났다. An experimental study was conducted to evaluate the breakout strength of stirrup-reinforced cast-in anchors under dynamic shear loadings. The shear loadings were applied in the manner specified in the ACI 355.2 and ETAG 001 for the seismic qualification tests. Test specimens were fabricated with M36 anchor (edge distance, 180mm) reinforced with D10 stirrups (spacing, 100mm). The specimens reached almost the breakout strength and thereafter fracture of anchor occurred. Additional tests with M42 anchor (edge distance, 160mm) reinforced with D6 bars (spacing, 100mm) were also conducted. The experimental results showed that the dynamic shear strength was not less than the static resistance. Based on the test results, it was shown that ACI 318 and ETAG 001 specifications estimate the breakout strength of stirrup-reinforced anchors conservatively as more reinforcement is provided.

SOM의 통계적 특성과 다중 스케일 Bayesian 영상 분할 기법을 이용한 텍스쳐 분할

김태형,엄일규,김유신,Kim Tae-Hyung,Eom Il-Kyu,Kim Yoo-Shin 대한전자공학회 2005 電子工學會論文誌-SP (Signal processing) Vol.42 No.6

이본 논문에서는 Bayesian 영상 분할법과 SOM(Self Organization feature Map)을 이용한 텍스쳐(Texture) 분할 방법을 제안한다. SOM의 입력으로 다중 스케일에서의 웨이블릿 계수를 사용하고, 훈련된 SOM으로부터 관측 데이터에 대한 우도(尤度, likelihood)와 사후확률을 구하는 방법을 제시한다. 훈련된 SOM들로부터 구한 사후확률과 MAP(Maximum A Posterior) 분류법을 이용하여 텍스쳐 분할을 얻는다. 그리고 문맥 정보를 이용하여 텍스쳐 분할 결과를 개선하였다. 제안 방법은 HMT(Hidden Markov Tree)을 이용한 텍스쳐 분할보다 더 우수한 결과를 보여준다. 또한 SOM과 HMTseg라고 불리는 다중스케일 Bayesian 영상 분할 기법을 이용한 텍스쳐 분할 결과는 HMT와 HMTseg을 이용한 결과보다 더 우수한 성능을 보여준다. This paper proposes a novel texture segmentation method using Bayesian image segmentation method and SOM(Self Organization feature Map). Multi-scale wavelet coefficients are used as the input of SOM, and likelihood and a posterior probability for observations are obtained from trained SOMs. Texture segmentation is performed by a posterior probability from trained SOMs and MAP(Maximum A Posterior) classification. And the result of texture segmentation is improved by context information. This proposed segmentation method shows better performance than segmentation method by HMT(Hidden Markov Tree) model. The texture segmentation results by SOM and multi-sclae Bayesian image segmentation technique called HMTseg also show better performance than by HMT and HMTseg.