• Architectural research
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• 제9권1호
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• pp.31-37
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• 2007

This study presents the so-called Modified Allowable Stress Design (MASD) method for structural designs. The objective of this study is to qualitatively estimate uncertainties of tensile steel member's cross-sectional structural designs and find the optimal resulting design which can resist all uncertainty cases. The design parameters are assumed to be interval associated with lower and upper bounds and consequently interval methods are implemented to non-stochastically produce design results including the structural uncertainties. By seeking optimal uncertainty combinations among interval parameters, engineers can qualitatively describe uncertain design solutions which were not considered in conventional structural designs. Under the assumption that structures have basically uncertainties like displacement responses, the safety range of resulting designs is represented by lower and upper bounds depending on given tolerance error and structural parameters. As a numerical example uncertain cross-sectional areas of members that can resist applied loads are investigated and it demonstrates that the present design method is superior to conventional allowable stress designs (ASD) with respect to a reliably structural safety as well as an economical material.

• Journal of Chest Surgery
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• 제17권2호
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• pp.189-196
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• 1984

Although the conventional methods of cardiopulmonary bypass for open heart surgery have been employed, it has been usual method to repair of congenital heart disease in infancy using deep hypother-mia and circulatory arrest technique. In 1980, we reported total correction of congenital heart disease using surface induced hypothermia-total circulatory arrest and rewarming with limited cardiopulmonary bypass. in 1981, three patients below 10 kilogram, who had ASD and PDA, and two of VSD with pulmonary hypertension were operated on using simple deep hypothermia without cardiopulmonary bypass. During surface cooling, there were no ventricular fibrillation and arrhythmia. There were no difficulties to resuscitate the heart. Postoperative respiratory and neurologic complication were not occurred. Follow up examination for two to three years gave no evidence of cerebral damage due to circulatory arrest.

• Journal of Chest Surgery
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• 제18권1호
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• pp.13-18
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• 1985

Cortriatriatum is rare congenital heart disease characterized by the presence of a fibromuscular diaphragm that subdivides the left atrium into a proximal or "accessory" and a distal or "true" left atrial chamber. A 15 year old girl with cortriatriatum underwent surgical correction at the department of Thoracic and Cardiovascular Surgery, Soonchunhyang College in November, 1984. This case was preoperatively diagnosed as a single atrium with functional tricuspid regurgitation But on operation, we found that there were transverse septum in the left atrium through large ASD, low chamber receives the pulmonary veins, and the upper chamber gives rise to the left atrial appendage and leads to the mitral valve. And the anomalous membrane has no fenestrations. We excised completely the anomalous septum, reconstructed atrial septal defect with dacron patch and performed the tricuspid annuloplasty with DeVega method. Postoperative course was uneventful during follow up, during follow up.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.1954-1959
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• 2014

This paper attempts to design and present a comparison of classical Direct Torque Flux Control (DTFC) for Line-Start Permanent Magnet Synchronous Motor (LSPMSM) and its equal Permanent Magnet Synchronous Motor (PMSM). In order to present an in-depth analysis, both motors for DTFC Voltage Source Inverter (VSI)-fed in the same situations of different conditions are simulated and tested. The advantages of the proposed method for LSPMSM over the PMSM are discussed and analyzed.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.512-517
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• 2009

Resistance factors for static bearing capacity of driven steel pipe piles were calibrated in the framework of reliability theory. A comprehensive foundation design case study on an actual bridge was performed using resistance factors developed in this study. Comparing with Allowable Stress Design (ASD), LRFD design method provides quantitative evaluation of safety level of designed foundation and exhibits considerable potential economy in design.

• 한국농공학회지
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• 제44권7호
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• pp.36-45
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• 2002

Most of rural bridges have passed 30 years of age since they were built, which have to support unexpected overload caused by changed design load and excessive amount of transportation. For these rural bridges, repairs and replacements are needed. Even though there have been attempt to estimate the safety of existing bridges deteriorated with major defects, those approaches must rely on the observable damage and subsequent decisions are made subjectively. To avoid the high cost of rehabilitation, the bridge rating must correctly represent the present load-carrying capacity. Rating engineers use a methods such as Allowable Stress Design (ASD), Load Factor Design (LFD), and Load Resistance Factor Design (LRFD) to evaluate the bridge load carrying capacity. In this paper, the load rating methods are introduced, and it is illustrated how to use the load test data from literature survey. Load test is conducted to the bridge that was built 30 years ago in rural area. From load test results, new maintenance method is suggested instead of the bridge replacement.

• Structural Engineering and Mechanics
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• 제29권4호
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• pp.391-410
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• 2008

In this article, a harmony search algorithm is presented for optimum design of steel frame structures. Harmony search is a meta-heuristic search method which has been developed recently. It is based on the analogy between the performance process of natural music and searching for solutions of optimization problems. The design algorithms obtain minimum weight frames by selecting suitable sections from a standard set of steel sections such as American Institute of Steel Construction (AISC) wide-flange (W) shapes. Stress constraints of AISC Load and Resistance Factor Design (LRFD) and AISC Allowable Stress Design (ASD) specifications, maximum (lateral displacement) and interstorey drift constraints, and also size constraint for columns were imposed on frames. The results of harmony search algorithm were compared to those of the other optimization algorithms such as genetic algorithm, optimality criterion and simulated annealing for two planar and two space frame structures taken from the literature. The comparisons showed that the harmony search algorithm yielded lighter designs for the design examples presented.

• Carbon letters
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• 제22권
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• pp.25-35
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• 2017

The aim of the work was to investigate the thermo-electrical properties of low cost and rapidly produced randomly oriented carbon/carbon (C/C) composite. The composite body was fabricated by combining the high-pressure hot-pressing (HP) method with the low-pressure impregnation thermosetting carbonization (ITC) method. After the ITC method step selected samples were graphitized at $3000^{\circ}C$. Detailed characterization of the samples' physical properties and thermal properties, including thermal diffusivity, thermal conductivity, specific heat and coefficient of thermal expansion, was carried out. Additionally, direct current (DC) electrical conductivity in both the in-plane and through-plane directions was evaluated. The results indicated that after graphitization the specimens had excellent carbon purity (99.9 %) as compared to that after carbonization (98.1). The results further showed an increasing trend in thermal conductivity with temperature for the carbonized samples and a decreasing trend in thermal conductivity with temperature for graphitized samples. The influence of the thickness of the test specimen on the thermal conductivity was found to be negligible. Further, all of the specimens after graphitization displayed an enormous increase in electrical conductivity (from 190 to 565 and 595 to 1180 S/cm in the through-plane and in-plane directions, respectively).

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권10호
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• pp.4976-4994
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• 2018

The diffusion-based salient object detection methods have shown excellent detection results and more efficient computation in recent years. However, the current diffusion-based salient object detection methods still have disadvantage of detecting the object appearing at the image boundaries and different scales. To address the above mentioned issues, this paper proposes a multi-scale diffusion-based salient object detection algorithm with background and objectness seeds. In specific, the image is firstly over-segmented at several scales. Secondly, the background and objectness saliency of each superpixel is then calculated and fused in each scale. Thirdly, manifold ranking method is chosen to propagate the Bayessian fusion of background and objectness saliency to the whole image. Finally, the pixel-level saliency map is constructed by weighted summation of saliency values under different scales. We evaluate our salient object detection algorithm with other 24 state-of-the-art methods on four public benchmark datasets, i.e., ASD, SED1, SED2 and SOD. The results show that the proposed method performs favorably against 24 state-of-the-art salient object detection approaches in term of popular measures of PR curve and F-measure. And the visual comparison results also show that our method highlights the salient objects more effectively.

• Journal of Chest Surgery
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• 제41권5호
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• pp.568-572
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• 2008

배경: 이미 여러 외과 영역에서 내시경수술이 보편화 되었고, 심장외과 영역에서도 그간 무펌프 관상 동맥우회술이나, 최소절개 또는 변형된 흉골절개 등을 이용한 최소침습수술이 꾸준히 시도되어 왔다. 하지만, 시야확보 및 체외순환을 위한 흉골절개의 필요성 때문에 이러한 변화에 둔감했던 것이 사실이다. 최근 로봇을 이용한 내시경 심장수술이 도입되는 것은 환영할 만한 일이나 고가의 장비가 필요하다는 문제가 있다. 이에 저자는 기존의 흉강경을 이용하여 심방중격결손의 폐쇄를 시행하였다 대상 및 방법: 2006년 5월부터 2008년 2월까지 15명의 환자를 대상으로 흉강경을 이용한 심방중격결손의 페쇄를 시행하였다. 수술 시 평균 연령은 $31{\pm}6$세였고 이들 중 2명을 제외하고는 모두 여자였다. 술전 심초음파상 심방중격결손의 평균 크기는 $24{\pm}5mm$였고, 삼첨판을 통한 압력차는 $30{\pm}5$ mmHg로 측정되었다. 삼첨판 페쇄부전은 3명에서는 경-중도였고 나머지에서는 경도 이하였으며, 1명에서 경-중도의 승모판폐쇄부전이 동반되었다. 수술은 우측 내경정맥과 대퇴동-정맥으로 캐뉼라를 삽관하여 체외순환을 시행하고, 유방하구를 따라 $4{\sim}5cm$의 소절개를 한 뒤 제4늑간을 통한 작업창과 흉강경으로 시야를 확보하며 심내교정을 시행하였다. 심방중격결손의 페쇄는 11명에서는 자가심낭을 이용하였고 4명에서는 일차봉합하였다. 관련 술기로는 3예의 삼첨판 성형술과 1예의 승모판 성형술을 시행하였다. 체외순환시간은 $160{\pm}47$분, 대동맥차단시간은 $70{\pm}26$분이었다. 결과: 술 후 사망 또는 주요합병증은 없었다. 3예에서 수혈이 필요하였고, 흉관제거 후 기흉이 관찰된 1예와 창상치유가 지연되었던 1예, 일시적인 부정맥의 1예 외에 별다른 합병증 없이 술 후 $5.9{\pm}1.8$일째 퇴원하였다. 술 후 시행한 심초음파 상 잔여 단락은 없었으며, 삼첨판폐쇄부전은 전예에서 경도 이하였다. 평균 추적관찰 기간은 $10.7{\pm}6.4$개월이었고 3명의 환자가 마지막 외래 방문 시 우측 가슴이나 대퇴부 안쪽의 감각이상을 호소하였으나 그 외 이상소견은 없었다. 결론: 저자들은 기존의 흉강경 장비를 이용한 심방중격결손의 페쇄로 술 후 만족할만한 임상적, 미용적 결과를 얻을 수 있었다. 그러나, 아직까지 수술시간이 많이 소요되며, 완전히 폐쇄된 공간 안에서의 수술이 아니고 작으나마 개흉이 필요하므로 향후 경험과 장비 면에서 보완이 필요하리라 생각된다.