HSB 강재 적용 강합성 복합단면 거더 정모멘트부의 휨저항강도

조은영,신동구,Cho, Eun-Young,Shin, Dong-Ku 한국강구조학회 2011 韓國鋼構造學會 論文集 Vol.23 No.3

교량용 HSB 고성능 강재를 적용한 정모멘트부 강합성 복합단면 거더의 휨저항강도를 모멘트-곡률 해석법으로 산정하고 LRFD 휨저항강도 설계식에 의한 휨저항강도와 비교하여 기존 설계식의 적용성을 검토하였다. 강거더의 하부플랜지는 HSB800 강재를 상부플랜지와 복부판은 HSB600 강재를 적용하였다. 다양한 연성특성을 갖는 6,205개 단면을 임의추출법으로 선정하고 재료 비선형 모멘트-곡률 해석 프로그램을 이용하여 이들 단면에 대한 휨저항강도를 구하였다. 합성단면을 구성하는 콘크리트 재료는 CEB-FIP 모델로, HSB600 및 HSB800 강재는 탄소성-변형경화 재료로 모델링하였으며 콘크리트 바닥판의 압축강도는 30MPa, 45MPa 및 60MPa를 고려하였다. HSB 강재를 적용한 강합성 복합단면 거더의 연성계수와 콘크리트 바닥판의 압축강도에 따른 휨저항강도 특성을 분석하였다. HSB 고성능강을 적용한 이종 복합단면 강합성 거더의 모멘트-곡률해석 결과, 현 AASHTO LRFD 정모멘트부 휨저항강도 산정식을 적용할 수 있는 것으로 평가되었다. The flexural strength of composite HSB hybrid I-girders under positive moment is investigated by the moment-curvature analysis method to evaluate the applicability of the current AASHTO LRFD design specification to such girders. The hybrid girders are assumed to have the top flange and the web fabricated from HSB600 steel and the bottom flange made of HSB800 steel. More than 6,200-composite I-girder sections that satisfy the section proportion limits of AASHTOL RFD specifications are generatedby the random sampling technique to consider a statistically meaningful wide range of section properties. The flexural capacities of the sections are calculated by the nonlinear moment-curvature analysis in which the HSB600 and HSB800 steels are modeled as an elastoplastic, strain-hardening material and the concrete as CEB-FIP model. The effects of ductility ratio and compressive strength of concrete slab on the flexural strength of composite hybrid girders make of HSB steels are analyzed. Numerical results indicated that the current AASHTO-LRFD equation can be used to calculate the flexural strength of composite hybrid girders fabricated from HSB steel.

국립장기이식센터 설립 전후의 각막이식 실태

조은영,김만수.Eun Young Cho. M.D.. Man Soo Kim. M.D. 대한안과학회 2006 대한안과학회지 Vol.47 No.4

Purpose: This study was performed to evaluate the status of corneal transplantation in Korea over the last 6 years. Methods: We evaluated the current status of domestic corneal transplantation using the data obtained from Korean Network for Organ Sharing (KONOS). We evaluated imported corneal transplantation by the number of corneal transplantations, the country of origin of imported cornea, the preserved state of corneas, the time from the death to transplantation and the result of corneal transplantation. The imported corneal transplantation data was obtained from the institution registered in KONOS and the institution recognized by the authers. Results: The number of domestic cornea donations has not increased since 2000, but the number of transplantations using imported corneas has increased year by year. The quality of imported corneas was good. There was no difference in operation results when domestic corneas were used compared to the use of imported corneas from the USA, Australia or Sri Lanka. Conclusions: The increased use of imported corneas results of a deficiency in the number of domestic cornea donations. Social motivation should be used to increase domestic donations of corneas.

양자컴퓨팅 소프트웨어 최신 기술 동향

조은영,김영철,정희범,차규일,Cho, E.Y.,Kim, Y.C.,Jung, H.B.,Cha, G.I. 한국전자통신연구원 2021 전자통신동향분석 Vol.36 No.6

Since Richard Feynman presented the concept of quantum computers, quantum computing have been identified today overcoming the limits of supercomputing in various applications. Quantum hardware has steadily developed into 50 to hundreds of qubits of various quantum hardware technologies based on superconductors, semiconductors, and trapped ions over 40 years. However, it is possible to use a NISQ (Noisy Intermediate Scale Quantum) level quantum device that currently has hardware constraints. In addition, the software environment in which quantum algorithms for problem solving in various applications can be executed is pursuing research with quantum computing software such as programming language, compiler, control, testing and verification. The development of quantum software is essential amid intensifying technological competition for the commercialization of quantum computers. Therefore, this paper introduces the trends of the latest technology, focusing on quantum computing software platforms, and examines important software component technologies.

콜린의 결핍과 서로 다른 지방이 2 - Acetylaminofluorene 을 투여한 쥐간의 Glutaghione 의존 효소에 미치는 영향

조은영,최혜미,김현아,변기원,송지현,김정희 ( Eun Young Cho,Hay Min Choi,Hyeona Kim,Ki Won Byun,Ji Hyun Song,Jun Ghee Kim ) 생화학분자생물학회 1992 BMB Reports Vol.25 No.4

Weanling Sprague-Dawley male rats were fed the diet containing either 15% beef tallow or 15% corn oil with or without 0.075% choline chloride for 10 weeks. At 3rd and 5th week, animals were given injection of 2-acetylaminofluorene (AAF) at a dose of 50 ㎎/㎏ body weight twice a week (1st and 3rd day of the week). At 11th week, all animals were decapitated. Microsomal lipid peroxide values, microsomal enzyme activities of glucose-6-phosphatase (G6Pase), cytosolic enzyme activities of glutathione peroxidase (GSH-Px), glutathione reductase (GR), glutathione S-transferase (GST) were determined. Microsomal lipid peroxide values measured as malondialdehyde (MDA) were increased significantly in choline deficient corn oil group, but not significantly in any other groups. Microsomal G6Pase activities were decreased in corn oil groups compared with beef tallow groups, and choline deficient corn oil group had the lowest value. Cytosolic GSH-Px activities tended to be elevated by choline deficiency in both fat groups. Cytosolic GR activities tended to be decreased by choline deficiency in beef tallow group, but significantly increased in corn oil group. Activities of cytosolic GST were tended to be increased by choline deficiency in both fat groups. All glutathione-dependent enzyme activities were significantly higher in corn oil groups than in beef tallow groups and the highest in choline deficient corn oil group. These results suggest that polyunsaturated fatty acid (PUFA) diet and choline deficiency may increase hepatic microsomal lipid peroxidation. Although lipid peroxidation induces protective enzymes, destruction of membrane integrity is inevitable. When 2 factors were compared on lipid peroxidation, induction of protective enzymes, and destruction of membrane integrity, PUFA diet was more effective than choline deficient diet.

결함허용 양자 컴퓨팅을 위한 양자 오류 복호기 연구 동향

조은영,온진호,김재열,차규일,E.Y. Cho,J.H. On,C.Y. Kim,G. Cha 한국전자통신연구원 2023 전자통신동향분석 Vol.38 No.5

Quantum error correction is a key technology for achieving fault-tolerant quantum computation. Finding the best decoding solution to a single error syndrome pattern counteracting multiple errors is an NP-hard problem. Consequently, error decoding is one of the most expensive processes to protect the information in a logical qubit. Recent research on quantum error decoding has been focused on developing conventional and neural-network-based decoding algorithms to satisfy accuracy, speed, and scalability requirements. Although conventional decoding methods have notably improved accuracy in short codes, they face many challenges regarding speed and scalability in long codes. To overcome such problems, machine learning has been extensively applied to neural-network-based error decoding with meaningful results. Nevertheless, when using neural-network-based decoders alone, the learning cost grows exponentially with the code size. To prevent this problem, hierarchical error decoding has been devised by combining conventional and neural-network-based decoders. In addition, research on quantum error decoding is aimed at reducing the spacetime decoding cost and solving the backlog problem caused by decoding delays when using hardware-implemented decoders in cryogenic environments. We review the latest research trends in decoders for quantum error correction with high accuracy, neural-network-based quantum error decoders with high speed and scalability, and hardware-based quantum error decoders implemented in real qubit operating environments.

LRFD 설계기준(안) 피로설계트럭 모형 분석

조은영,신동구,Cho, Eun Young,Shin, Dong Ku 한국강구조학회 2009 韓國鋼構造學會 論文集 Vol.21 No.3

A reliability analysis of the fatigue failure of highway steel bridges was performed by applying the Miner's fatigue damage rule for the fatigue design truck proposed for the LRFD code and for the current DB 24 truck. The limit state function for fatigue failure is expressed as a function of various random variables that affect fatigue damage. Among these variables, the statistical parameters for the equivalent moment, the impact factor, and the loadometer were obtained by analyzing recently measured domestic traffic data, and the parameters for the fatigue strength, the girder distribution factor, and the headway factor were obtained from the measured data reported in literature. Based on the reliability analysis, the fatigue truck model for the LRFD code was proposed. After applying the proposed fatigue truck to the LRFD code, 16 composite plate and box girder bridges were designed based on the LRFD method, and the LRFD design results for the fatigue limit state were compared with those by the current KHBDC. Miner의 피로손상법칙을 적용하여 피로파괴에 대한 한계상태함수를 표현하고, 실제 국내 통행차량의 통계적 특성을 반영하여 LRFD 설계기준(안)의 피로설계트럭모형과 현 도로교설계기준의 DB-24 하중에 대한 피로파괴 신뢰도해석을 수행하였다. 피로한계상태함수는 Miner의 피로손상법칙을 확률변수의 함수로 나타내고 이들 확률변수에 대하여 국내 통행트럭 등의 실측 통계자료를 분석하여 구한 통계치와 문헌에 보고된 결과를 조사하여 구한 통계치를 적용하여 지간별 및 피로상세별 신뢰도지수를 Rackwitz-Fiessler법으로 구하고, 신뢰도해석 결과를 분석하여 LRFD 설계기준(안)의 피로설계트럭모형을 제안하였다. 아울러, 제안된 피로설계트럭모형을 적용하여 단경간 및 3경간 연속 플레이트 및 박스 거더교의 총 16개 실교량에 대한 피로설계를 수행하고, 설계결과를 현 도로교설계기준의 DB-24 하중에 의한 피로설계 결과와 비교하여 LRFD 피로설계트럭 모형의 적용성을 검토하였다.

하악치은에 발생한 평활근육종의 치험례

조은영,하종운,김은철,정윤심,Cho, Eun-Young,Ha, Jong-Woon,Kim, Eun-Cheol,Jeong, Yun-Shim 대한구강악안면외과학회 2001 대한구강악안면외과학회지 Vol.27 No.4

Leiomyosarcoma(LMS) is a malignant tumor from smooth muscle origin that arises most commonly in the gastrointestinal tract and uterus, but rarely in the oral and maxillofacial area which lacks smooth muscles. 63 cases of oral LMS have been reported, especially LMS that occurred in the mandibular gingiva is only 2 cases. Major symptom of oral LMS is painful or painless swelling. Besides it, oral LMS has no specific characteristics. So it is difficult to diagnose the case as LMS of the oral cavity. Certain cases report that LMS of the oral cavity was misdiagnosed as periodontitis and the patients were treated with unnecessary procedures. Conventional treatment of LMS is the radical surgical excision. LMS that is infiltrative and very malignant has poor prognosis despite of well-circumscribed boundary. LMS of the oral cavity is often recurred, has high rate of distant metastasis and 5-year-survival rate is as low as 23%. This article reports LMS of the mandibular gingiva that treated with surgical intervention, had local recurrence and metastasis to the lymph node after 16-month's follow-up examination.

HSB 강거더의 비탄성 횡비틂좌굴에 의한 휨강도 - 세장 복부판 단면

조은영,신동구,Cho, Eun-Young,Shin, Dong-Ku 한국강구조학회 2012 韓國鋼構造學會 論文集 Vol.24 No.2

The flexural behavior of HSB I-girder with a non-slender web attributed to inelastic lateral-torsional buckling under uniform bending was investigated using nonlinear finite element analysis of ABAQUS. The girder was assumed to have a compact or noncompact web in order to prevent premature bend-buckling of the web. The unbraced length of the girder was selected so that inelastic lateral-torsional buckling governs the ultimate flexural strength. The compression flange was also assumed to be either compact or noncompact to prevent local buckling of the elastic flange. Both homogeneous sections fabricated from HSB600 or HSB800 steel and hybrid sections with HSB800 flanges and SM570-TMC web were considered. In the FE analysis, the flanges and web of I-girder were modeled as thin shell elements. Initial imperfections and residual stresses were imposed on the FE model. An elasto-plastic strain hardening material was assumed for steel. After establishing the validity of the present FE analysis by comparing FE results with test results in existing literature, the effects of initial imperfection and residual stress on the inelastic lateral-torsional buckling behavior were analyzed. Finite element analysis results for 96 sections demonstrated that the current inelastic strength equations for the compression flange in AASHTO LTFD can be applied to predict the inelastic lateral torsional buckling strength of homogeneous and hybrid HSB I-girders with a non-slender web. HSB 고강도 강재를 적용한 균일모멘트를 받는 세장 복부판을 갖는 강거더에 대하여 비탄성 횡비틂좌굴 거동을 상용 ABAQUS 프로그램을 이용하여 비선형 유한요소해석으로 분석하였다. 해석대상 강거더는 압축플랜지의 국부좌굴이 휨강도를 지배하지 않도록 플랜지는 조밀 또는 비조밀 요소에 해당하는 세장비를 갖도록 설계하였으며, 횡방향 비지지길이는 탄성 횡비틂좌굴 강도 이상의 휨강도를 갖도록 선정하였다. HSB600 및 HSB800 강재로 제작된 균질단면 강거더와 HSB800과 SM570-TMC 강재를 동시에 적용한 하이브리드 단면를 고려하였고, 일반강재와의 상대적인 비교를 위하여 SM490-TMC 균질단면 강거더에 대한 해석도 수행하였다. 비선형 유한요소해석 시에는 플랜지와 복부판을 쉘요소로, 강재는 탄소성-변형경화 재료로 모델링하였다. 초기변형과 단면의 잔류응력을 고려하였으며 이들이 비탄성 횡비틂좌굴 영역에서 휨거동에 미치는 영향을 분석하였다. 총 64개의 해석대상 강거더에 대하여 FE 해석과 설계식에 의한 휨저항강도를 비교한 결과, HSB 강재를 적용한 균질단면 및 하이브리드 단면 거더의 비탄성 횡비틂좌굴에 의한 휨강도는 현 AASHTO LRFD 압축플랜지 휨강도 탄성 설계규정을 적용하여 산정할 수 있는 것으로 분석되었다.

압축플랜지 비탄성 국부좌굴을 고려한 HSB 플레이트거더의 휨강도

조은영,신동구,Cho, Eun Young,Shin, Dong Ku 대한토목학회 2013 대한토목학회논문집 Vol.33 No.1

HSB를 적용한 플레이트거더의 압축플랜지 국부좌굴을 고려한 극한휨강도를 비선형 유한요소해석으로 분석하였다. 압축플랜지의 비탄성 국부좌굴 또는 소성항복이 휨강도를 지배하는 압축플랜지 세장비를 갖도록 해석대상 강거더를 선정하였다. HSB600 및 HSB800 강재로 제작된 균질단면 강거더와 HSB800 강재와 SM570-TMC 강재를 함께 적용한 하이브리드 단면을 고려하였으며, 일반강재와의 비교를 위하여 SM490-TMC 강거더에 대한 해석도 수행하였다. 비선형 유한요소해석 시에는 플랜지와 복부판을 쉘요소로 강재는 탄소성-변형경화 재료로 모델링하였으며, 초기변형과 단면의 잔류응력을 고려하였다. 비선형 유한요소해석 결과와 기존 문헌의 실험결과를 비교하여 유한요소 해석결과를 검증하였으며, 초기변형과 잔류응력이 극한휨강도에 미치는 영향을 분석하였다. 총 60개 해석대상 강거더의 휨극한강도를 유한요소해석으로 구하고, 도로교설계기준, AASHTO LRFD와 Eurocode 3의 설계규정으로 구한 휨강도와 비교하여 이들 규정의 HSB 강거더에 대한 적용성을 검토하였다. The ultimate flexural strength of HSB I-girders, considering the effect of local bucking, was investigated through a series of nonlinear finite element analysis. The girders were selected such that the inelastic local flange buckling or the plastic yielding of compression flanges governs the flexural strength. Both homogeneous sections fabricated from HSB600 or HSB800 steel and hybrid sections with HSB800 flanges and SM570-TMC web were considered. In the FE analysis, the flanges and web were modeled using thin shell elements and initial imperfections and residual stresses were imposed on the FE model. An elasto-plastic strain hardening material was used for steels. After establishing the validity of present FE analysis by comparing FE results with test results published in the literature, the effects of initial imperfection and residual stress on the inelastic flange local buckling behavior were assessed. The ultimate flexural strengths of 60 I-girders with various compression flange slenderness were obtained by FE analysis and compared with those calculated from the KHBDC, AASHTO LRFD and Eurocode 3 provisions. Based on the comparison, the applicability of design equations in these specifications for the flexural strength of I-girder considering flange local buckling was evaluated.

비탄성 설계법에 의한 플레이트 거더 연속교의 LRFD 설계

조은영,신동구,Cho, Eun Young,Shin, Dong Ku 한국강구조학회 2008 韓國鋼構造學會 論文集 Vol.20 No.4

연속경간 강합성 플레이트 거더교를 내측 교각 위 부모멘트부에서의 모멘트 재분배 효과를 고려하는 LRFD 비탄성설계법으로 설계하고 탄성설계법에 의한 설계결과와 비교하였다. 탄성 및 비탄성 설계 시에 교량은 3경간 연속교로 가정하였으며 경간비를 4:5:4로 중앙 경간 최대 경간장은 40m-70m를 고려하였다. 설계방법은 AASHTO-LRFD 규정을 적용하였으나 설계활하중은 최근 국내에서 새로이 제안된 활하중을 사용하였다. 탄성설계법으로 최대정모멘트 단면과 내측 교각 위 최대부모멘트 단면을 설계한 후에 내측 교각 위에서의 재분배모멘트를 계산하고 이를 최대정모멘트부의 설계모멘트에 추가하여 최대정모멘트부 단면에 대한 강도한계상태와 사용성한계상태에 대하여 검토하였다. 최대부모멘트부는 탄성설계법으로 구한 강거더 단면의 강재량을 감소시키고 비탄성설계법에 규정한 사용성한계상태 설계요구조건을 검토하였다. 5개의 연속교를 비탄성설계법으로 설계한 결과 최대부모멘트부의 강거더 단면적이 탄성설계에 비해 23% 내외 감소하는 것으로 분석되었다. The inelastic design of the three-span continuous composite plate girder with consideration of moment redistribution over the interior pier is performed using the LRFD method. The design of the girder section, based on the inelastic method, is compared with that by the conventional elastic design. The length of the center span for the three-span continuous bridge ranges from 40m to 70m and the relative ratio of the span length is assumed to be 4:5:4. Although the AASHTO- LRFD specifications are applied in the design of the composite girder, the recently proposed new design live load is used. After determining the maximum positive and negative sections by the elastic design for various limit states, the amount of moment redistributed to the maximum positive moment section is calculated. With the increased design moment due to moment redistribution from the interior pier, the maximum positive section designed by the elastic method is checked for the strength limit state and the service limit state. The maximum negative moment section is redesigned by reducing the size of the steel girder relative to the section designed by the elastic method and the new section is checked for the service limit state. Based on the design results for the five bridges considered in this study, it is estimated that about 23% of steel can be saved in the interior pier section if it is designed by the inelastic method compared with that designed by the elastic method.