• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1571-1584
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• 2023

In this study, a numerical analysis was performed as part of an international joint research project to reproduce a real cable tray fire that occurred in the heater bay area of the turbine building of a nuclear power plant. A sensitivity analysis was performed on various input parameters to derive results consistent with the sprinkler activation time obtained from the fire event analysis. For all sensitive parameters, the normalized sprinkler activation time correlated well with the power function of the normalized sprinkler height. A correlation equation was developed to identify the sprinkler activation time at any location when determining the slope or fire growth rate under the conditions assuming a linear or t-squared heat release rate (HRR) time curve. Various cable fire growth assumptions were used to determine which assumption was better to provide the prediction coincident with the information given from the fire event analysis in terms of the sprinkler activation time and total energy generated from cables damaged by fire. In the comprehensive analysis of all the sensitive parameters, the standard deviation of the input parameters increased as the sprinkler height decreased. Within the range of the sensitivity parameter values given in this study, when considering all sprinkler heights, the standard deviation of the cable model change was the largest and that of the overhang position change was the smallest.

• Structural Engineering and Mechanics
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• 제91권3호
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• pp.279-289
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• 2024

The purpose of this study is to represent a useful alternative for the preliminary seismic vulnerability assessment of existing reinforced concrete buildings by introducing a statistical approach employing the binary logistic regression technique. Two different predictive statistical models, namely full and reduced models, were generated utilizing building characteristics obtained from the damage database compiled after 1999 Düzce earthquake. Among the inspected building parameters, number of stories, overhang ratio, priority index, soft story index, normalized redundancy ratio and normalized lateral stiffness index were specifically selected as the predictor variables for vulnerability classification. As a result, normalized redundancy ratio and soft story index were identified as the most significant predictors affecting seismic vulnerability in terms of life safety performance level. In conclusion, it is revealed that both models are capable of classifying the set of buildings being severely damaged or collapsed with a balanced accuracy of 73%, hence, both are able to filter out high-priority buildings for life safety performance assessment. Thus, in this study, having the same high accuracy as the full model, the reduced model using fewer predictors is proposed as a simple and viable classifier for determining life safety levels of reinforced concrete buildings in the preliminary seismic risk assessment.

• Archives of Plastic Surgery
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• 제43권2호
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• pp.204-209
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• 2016

Temporal hollowing occurs to varying degrees after pterional craniotomy. The most common cause of temporal hollowing is a bony defect of the pterional and temporal regions due to the resection of the sphenoid ridge and temporal squama for adequate exposure without overhang. The augmentation of such bony defects is important in preventing craniofacial deformities and postoperative hollowness. Temporal cranioplasty has been performed using a range of materials, such as acrylics, porous polyethylene, bone cement, titanium, muscle flaps, and prosthetic dermis. These methods are limited by the risk of damage to adjacent tissue and infection, a prolonged preparation phase, the possibility of reabsorption, and cost inefficiency. We have developed a method of temporal augmentation using a calvarial onlay graft as a single-stage neurosurgical reconstructive operation in patients requiring craniotomy. In this report, we describe the surgical details and review our institutional outcomes. The patients were divided into pterional craniotomy and onlay graft groups. Clinical temporal hollowing was assessed using a visual analog scale (VAS). Temporal soft tissue thickness was measured on preoperative and postoperative computed tomography (CT) studies. Both the VAS and CT-based assessments were compared between the groups. Our review indicated that the use of an onlay graft was associated with a lower VAS score and left-right discrepancy in the temporal contour than were observed in patients undergoing pterional craniotomy without an onlay graft.

• 조명전기설비학회논문지
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• 제20권8호
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• pp.80-87
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• 2006

본 논문에서는 3차원 FEM을 이용하여 Claw pole stoning motor의 특성을 해석하였다. Claw pole stewing motor는 구조상 z-축 방향으로 자화가 발생하고 모델의 특성상 3차원 FEM해석이 필수적이다. 해석 시간을 고려해 볼 때 목적하고자 하는 성능을 갖는 모터 설계 시 시간을 효율적으로 줄이기 위한 방법 중 하나는 해석 대상의 개수를 줄이는 것이다. 이에 본 논문에서는 실험계획법(Design of Experiments)을 이용하여 Claw pole stewing motor의 해석 및 설계 시 중요 변수인 영구자석, 폴형상, 권선수의 설계 변수를 설정하여 이 설계변수의 조합으로 나오는 해석 모델의 개수를 최소화하고 이렇게 줄어든 최적의 모델을 선정하여 3차원 FEM으로 해석하여 특성을 살펴보았다.

• Biomolecules & Therapeutics
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• 제26권3호
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• pp.282-289
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• 2018

Melanin is a pigment produced from tyrosine in melanocytes. Although melanin has a protective role against UVB radiation-induced damage, it is also associated with the development of melanoma and darker skin tone. Tyrosinase is a key enzyme in melanin synthesis, which regulates the rate-limiting step during conversion of tyrosine into DOPA and dopaquinone. To develop effective RNA interference therapeutics, we designed a melanin siRNA pool by applying multiple prediction programs to reduce human tyrosinase levels. First, 272 siRNAs passed the target accessibility evaluation using the RNAxs program. Then we selected 34 siRNA sequences with ${\Delta}G{\geq}-34.6kcal/mol$, i-Score value ${\geq}65$, and siRNA scales score ${\leq}30$. siRNAs were designed as 19-bp RNA duplexes with an asymmetric 3' overhang at the 3' end of the antisense strand. We tested if these siRNAs effectively reduced tyrosinase gene expression using qRT-PCR and found that 17 siRNA sequences were more effective than commercially available siRNA. Three siRNAs further tested showed an effective visual color change in MNT-1 human cells without cytotoxic effects, indicating these sequences are anti-melanogenic. Our study revealed that human tyrosinase siRNAs could be efficiently designed using multiple prediction algorithms.

• 한국철도학회논문집
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• 제13권4호
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• pp.404-411
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• 2010

철도차량용 선형유도전동기(Linear Induction Motor, LIM) 축소-회전형 모델의 기본 설계 결과를 검증하기 위하여 LIM의 자기등가회로법을 이용한 파라미터 도출 및 특성 계산을 수행하였다. LIM의 경우, 자기등가회로상의 파라미터는 LIM의 전기자 코어와 2차측 알루미늄 도체판의 형상 및 공극에 대한 함수로써 표현이 가능하다. 즉 전기자 코어와 2차측 알루미늄 도체판의 형상 및 공극 변경에 의해 LIM의 특성이 크게 달라질 수 있다는 것을 의미한다. 따라서 본 연구에서는 철도차량용 LIM 축소-회전형 모델의 공극, 2차측 AL-Plate의 두께, 오버행 길이, 형상 변경에 따른 LIM 축소-회전형 모델의 자기등가회로 파라미터 및 특성의 변화 추세를 분석하여, 철도차량용 실모델 LIM 개발을 위한 기초 연구를 수행하였다.

• 한국ITS학회 논문지
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• 제10권5호
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• pp.47-52
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• 2011

본 연구는 차량 제원이 유사한 2축 차량의 차종분류에 있어서 정확도를 높이고자 차량 외형의 높이 프로파일을 이용한 차종분류 방안을 제시했다. 차종별 교통량 자료 생성은 도로를 주행하는 차량을 대상으로 AVC장비에서 계측되는 차량 제원들인 축수, 축간거리, 차량길이, 오버행 등을 활용하여 12종 분류 체계에 의해서 분류되고 있다. 그러나 차량 축이 2개인 2축 차량(1~4종 차량)의 경우 승용차(1종)의 다양화, 대형화로 인하여 화물수송용 차량(3종, 4종)의 제원과 유사해짐에 따라 기존 차량분류인자(축수, 축간거리, 차량길이 등)에 의한 차종분류 시 분류 오류가 발생할 수 있다. 이에 본 연구는 이러한 분류상의 한계를 극복하고자 차량 외관의 높이 프로파일 값을 통하여 주행차량의 형태를 파악하고 이를 이용한 차종분류 방법을 제시하였다. 그리고 현장실험을 통하여 제안된 방법의 정확도를 검증하였다.

• 대한교통학회지
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• 제27권4호
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• pp.55-61
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• 2009

차종분류는 교통의 흐름 및 안전에 미치는 영향을 분석하고 도로의 포장 및 시설의 설계를 위하여 이루어진다. 국내에서는 국토해양부의 12종 분류에 따라 고속국도, 일반국도, 지방도의 차종분류 자료가 제공되고 있다. 기계식 차종분류를 위한 AVC(Automatic Vehicle Classification) 장비는 차량길이, 축거, 내민 거리(overhang) 등의 측정값과 미리 입력된 모든 차량 모델의 제원값을 비교하여 차종을 판단한다. 하지만, 기존의 방법은 센서의 관리상태에 분류 정확도가 크게 영향받게 된다. 본 연구에서는 실제 조사지점에서 발생하는 장비 오차와 차량 제원정보에 민감하지 않은 차종분류 알고리즘을 개발하였다. 알고리즘을 단순화하기 위하여 차량길이와 축거 중심으로 추세선을 이용하여 차종을 분류하므로 센서의 정확도 변화의 영향을 감소시켰다. 개발된 알고리즘의 평가를 위하여 일반국도에 설치된 AVC 장비에서 축수, 차량길이, 축거, 내민거리를 추출하여 비디오 판독 결과와 비교하였다. 실험 결과는 전체 차량에 대하여 88.2%의 정확도를 얻었다. 본 연구에서 개발된 차종분류 알고리즘은 센서의 감도 변화 등 현장 환경의 변화에 덜 영향을 받도록 설계되어 차종분류를 위한 기계식 장비의 안정적 정확도 유지에 활용될 수 있을 것으로 기대된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.53-53
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• 2011

As the dimension of Cu interconnects has continued to reduce, its resistivity is expected to increase at the nanoscale due to increased surface and grain boundary scattering of electrons. To suppress increase of the resistivity in nanoscale interconnects, alloying Cu with other metal elements such as Al, Mn, and Ag is being considered to increase the mean free path of the drifting electrons. The formation of Al alloy with a slight amount of Cu broadly studied in the past. The study of Cu alloy including a very small Al fraction, by contrast, recently began. The formation of Cu-Al alloy is limited in wet chemical bath and was mainly conducted for fundamental studies by sputtering or evaporation system. However, these deposition methods have a limitation in production environment due to poor step coverage in nanoscale Cu metallization. In this work, gap-filling of Cu-Al alloy was conducted by cyclic MOCVD (metal organic chemical vapor deposition), followed by thermal annealing for alloying, which prevented an unwanted chemical reaction between Cu and Al precursors. To achieve filling the Cu-Al alloy into sub-100nm trench without overhang and void formation, furthermore, hydrogen plasma pretreatment of the trench pattern with Ru barrier layer was conducted in order to suppress of Cu nucleation and growth near the entrance area of the nano-scale trench by minimizing adsorption of metal precursors. As a result, superconformal gap-fill of Cu-Al alloy could be achieved successfully in the high aspect ration nanoscale trenches. Examined morphology, microstructure, chemical composition, and electrical properties of superfilled Cu-Al alloy will be discussed in detail.

• Clinics in Shoulder and Elbow
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• 제22권1호
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• pp.24-28
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• 2019

Background: Glenoid baseplate location is important to good clinical outcomes of reverse total shoulder arthroplasty (RTSA). The glenoid vault is the determining factor for glenoid baseplate location, but, to date, there are no reports on the effect of central cage location within the glenoid vault on RTSA outcomes when using the $Exactech^{(R)}$ $Equinoxe^{(R)}$ Reverse System. The purpose of this study was to determine the appropriate cage location in relation to the glenoid vault and monitor for vault and/or cortex penetration by the cage. Methods: Data were retrospectively collected from the Samsung Medical Center (SMC) and Seoul National University Bundang Hospital (SNUBH). Patients who underwent RTSA between November 2016 and February 2018 were enrolled. Glenoid vault depth, central cage location within the vault were examined. Inferior glenoid rim-center distance, inferior glenoid rim-cage distance, and center-cage center distances were collected. Results: Twenty-two patients were enrolled. Three SNUBH patients had inappropriate central cage fixation (33.3%) versus 4 SMC patients (30.8%). All cage exposures were superior and posterior to the glenoid vault. Mean center-cage distance was 5.0 mm in the SNUBH group and 5.21 mm in the SMC group. Center-prosthesis distance was significantly longer in the inappropriate fixation group than in the appropriate fixation group (p<0.024). Conclusions: To ensure appropriate glenoid baseplate fixation within the glenoid vault, especially in a small glenoid, the surgeon should place the cage lower than usually targeted, and it should overhang the inferior glenoid rim.