• 한국대기환경학회지
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• 제32권4호
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• pp.408-421
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• 2016

Day and night sampling for gas and particle phases PAHs were carried out in Seoul to characterize gas and particle phases PAHs concentrations in day and night times. There was no significant difference between day and night time for particle phase PAHs concentrations and phase distribution of PAHs, while, gas phase PAHs concentrations in daytime were about 1/2 of nighttime concentrations in both summer and winter due to photochemical reaction of gas phase PAHs during daytime. A high fraction of cancer risk for PAHs was attributed to particle phase PAHs and the excess cancer risk in winter was higher than in summer. The excess cancer risk level of total(gas+particle) PAHs in summer was partially observed when both gas and particle phase PAHs concentrations were considered as risk assessment. Based on the diagnostic ratios and factor analysis of PAHs concentrations, combustion(coal and natural gas) and vehicular emission might be the most significant contributors of PAHs and major factors for determining of PAHs concentration were different between day and night times.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제16권5호
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• pp.571-575
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• 2010

클래스 수준 뮤테이션 분석(class-level mutation analysis)의 경우, 동등 뮤턴트(equivalent mutant)는 전체 뮤턴트들의 개수에서 많은 비중을 차지하기 때문에 동등 뮤턴트의 검출은 뮤테이션 수행 비용 절감에 매우 중요하다. 하지만 현재까지 클래스 수준 뮤테이션을 대상으로 동등 뮤턴트를 검출하는 연구는 미미한 실정이다. 본 논문에서는 클래스 수준 뮤테이션을 대상으로 의존성 그래프(dependency graph)를 이용하여 동등 뮤턴트를 검출하기 위한 기법을 제안한다. 제안한 기법은 인트라-클래스(intra-class) 수준에서 정적분석을 수행함으로써 인트라-메소드(intra-method) 수준의 분석 방법을 사용하는 기존의 연구들이 검출할 수 없었던 클래스 수준 동등 뮤턴트를 검출할 수 있었다.

• 한국대기환경학회지
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• 제12권3호
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• pp.269-278
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• 1996

Airborne suspended particulates were collected by an Andersen high volume air sampler in a traffic area of Seoul from September 1990 to August 1991. Origanic matter extracted from particulates, their fractions, namely acidic, basic, neutral and carcinogenic subfractions (PAHs, nitroarenes) in neutral fractions were assayed for mutagenicity on TA98, TA100 and TA98NR deficient Salmonella strains, use of the pre-incubation method. The relative contribution to total mutanenicity of organic matters was highest in neutral fraction and was lowest in basic fraction. Among subfractions, that of neutral fraction was higher nitroarenes subfraction compared to PAHs subfraction. While the carcinogenic effect of benzo[a]pyrene was calculated as 0.96 persons/million persons based on unit risk estimates by extrapolation method, life time excess cancer risk estimate of EOM, neutral, PAH fraction based on their mutagenicity was calculated as 52, 42, 3.8 persons/million persons, respectively. These findings indicate that the mutagenic hazard of the partciculate, air organic complex mixture, may be dependent upon the mutagen composition in the particulate and interactions each of them. Therfore, health risk from air organic complex mixtures based on mutagenicity might be useful indicator for evaluation of actual risk.

• 대한기계학회논문집A
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• 제37권9호
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• pp.1151-1158
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• 2013

습기 수착 물성은 전자 패키징 장치의 신뢰성에 있어서 층간의 수증기 압력에 의해 공정과정 동안 발생되는 박리 불량의 고장 분석 및 최적의 재료 개발에 있어서 필수적이다. 본 논문에서는 온습도 모델에 따른 전자 패키징 재료의 온도 의존적인 흡습 및 탈습 물성을 변수화 하였고 이에 대한 온도 및 습도의 영향에 대해 고찰하였다. 변수화된 확산성에서 얻어진 확산 활성화 에너지는 등가의 습기 수착 수준을 위한 가속 수명 비율을 결정하고 신뢰 수명 평가에 요구되는 등가의 소요 시험 시간에 미치는 습기 확산성의 영향을 예측할 수 있게 한다. 신뢰성 시험 표준에서 평가된 유연 전자 모듈의 가속 수명비율을 예시하였다.

• Mass Spectrometry Letters
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• 제6권3호
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• pp.53-58
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• 2015

Recombinant erythropoietins (EPOs) are an important class of biotherapeutics that stimulate red blood cell production. The quality, safety, and potency of EPO variants are determined largely by their glycosylation, which makes up nearly half their mass. Thus, detailed glycomic analyses are important to assess biotherapeutic quality and establish the equivalency of biosimilar EPOs now coming to market. High-resolution mass spectrometry (MS) has recently emerged as the premier tool for glycan analysis in EPOs. Using the accurate mass measurements provided by high-resolution MS, the compositions of even large, complex glycans can easily be determined. When combined with a nano-LC separation, differentiation of structural isomers also becomes a possibility. These components, together, provide a comprehensive picture of biotherapeutic glycosylation. In this review, we provide an overview of MS-based analytical platform for glycomic characterization of EPO biotherapeutics and biosimilars.

• 한국통신학회논문지
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• 제31권3B호
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• pp.175-182
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• 2006

본 논문에서는 Localized Aptive QoS 라우팅을 위해 POMDP(Partially Observable Markov Decision Processes)와 Exploration Bonus 기법을 사용하는 방법을 제안하였다. 또한, POMDP 문제를 해결하기 위해 Dynamic Programming을 사용하여 최적의 행동을 찾는 연산이 매우 복잡하고 어렵기 때문에 CEA(Certainty Equivalency Approximation) 기법을 통한 기댓값 사용으로 문제를 단순하였으며, Exploration Bonus 방식을 사용해 현재 경로보다 나은 경로를 탐색하고자 하였다. 이를 위해 다중 경로 탐색 알고리즘(SEMA)을 제안했다. 더욱이 탐색의 횟수와 간격을 정의하기 위해 $\phi$와 k 성능 파라미터들을 사용하여 이들을 통해 탐색의 횟수 변화를 통한 서비스 성공률과 성공 시 사용된 평균 홉 수에 대한 성능을 살펴보았다. 결과적으로 $\phi$ 값이 증가함에 따라 현재의 경로보다 더 나은 경로를 찾게 되며, k 값이 증가할수록 탐색이 증가함을 볼 수 있다.

• Structural Engineering and Mechanics
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• 제21권6호
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• pp.737-765
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• 2005

This paper presents a theoretical model for the behavior of partially confined axi-symmetric reinforced concrete members subjected to axial load. The analysis uses the theories of elasticity and plasticity to cover the full range of the concrete behavior. Analysis of the elastic range of the problem involves boundary conditions that are defined along a relatively simple geometry. However, extending the analysis into the plastic range involves difficulties that arise from the irregular geometry of the boundary between the plastic zone and the elastic zone, a boundary which is also changing as the axial load increases. The solution is derived by replacing the discrete steel ties with an equivalent tube of thickness $t_{eq}$ and by analyzing the concrete cylinder, which is uniformly confined by the equivalent tube. The equivalency criterion initiates from a theoretical analysis of the problem in its elastic range where further finite element analysis shows that this criterion is valid also for the plastic range of the cylinder material. According to the proposed model, the efficiency of the lateral reinforcement can be evaluated by the equivalent thickness $t_{eq}$. Comparison with published test results of confined reinforced concrete stress-strain curves shows good agreement between the test and the analytical results.

• Journal of Gastric Cancer
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• 제12권2호
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• pp.63-72
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• 2012

Since the first laparoscopic gastrectomy for cancer was reported in 1994, minimally invasive surgery is enjoying its wide acceptance. Numerous procedures of this approach have developed, and many patients have benefited from its effectiveness, which has been recently demonstrated for early gastric cancer. However, since laparoscopic surgery is not exempt from some limitations, the robotic surgery system was introduced as a solution by the late 1990's. Many experienced surgeons have embraced this new emerging method that provides undoubted technical and minimally invasive advantages. To date, several studies have concentrated to this new system, and have compared it with open and laparoscopic approach. Most of them have reported satisfactory results concerning the post-operative short-term outcomes, but almost all believe that the role of robotic gastrectomy is still out of focus, especially because long-term outcomes that can prove robotic oncologic equivalency are lacking, and operative costs and time are higher in comparison to the open and laparoscopic ones. This article is a review about the current status of robotic surgery for the treatment of gastric cancer, especially, focusing on the technical aspects, comparisons to other approaches and future prospects.

• 한국물환경학회지
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• 제21권3호
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• pp.219-229
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• 2005

The analytical methods for dioxins in water sample from wastewater to tap water were reviewed. For extraction method, liquid-liquid extraction (LLE) has been widely used, however, this process needs too much time and man power. New approach including solid phase extraction (SPE) is now applicable to large volume of water sample with high extraction efficiency. Column clean up in classical analytical methods were very complex and time consuming procedures during decade. Modifications were tried to decrease solvent and reagents volume. Moreover, use of column connection method has been demonstrated in the environmental matrices. Instrumental configurations also have been improved, in which GC/MS/MS with large volume injection approach can analyze picogram levels. Absolute sensitivities of HRMS increased compared to old versions of double focusing sector type mass spectrometers. Based on these analytical evolutions during last 10 years, we tried to optimize the analytical method for dioxins in water sample from sample extraction to instrumental analysis.

• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1318-1322
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• 2021

To unveil and delineate the elements applicable to the radiation protection of a femoral entry shield, calculate its mass attenuation coefficient, and demonstrate its dose reduction efficacy for interventional radiologist performing transarterial embolization (TAE) of ruptured hepatocellular carcinoma (rHCC). The lead equivalency of the shield was firstly validated. Electron microscopy was used to confirm the femoral entry shield being lead-free and to analyze the elemental content, with which the mass attenuation coefficient of the shield was calculated. An adult phantom, irradiated at the upper abdomen to simulate the TAE of rHCC, was used together with a dosimeter attached to the palm of a hand phantom. The dose rates at the hand phantom were measured, with the rHCC clinical protocol, without and with the femoral entry shield placed over the right femoral access site of the adult phantom. Without using the shield, the average hand dose rate was measured to be 0.325 µSv/sec. While using the shield, it was determined to be 0.110 µSv/sec. There was significant 66% dose reduction to the hand dose of IRs performing angiographic intervention with the femoral entry shield.