• 대한수학회보
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• 제54권3호
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• pp.737-746
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• 2017

In this paper, we discuss the existence theorem for multiple vortex solutions in the non-Abelian Chern-Simons-Higgs field theory developed by Aharony, Bergman, Jafferis, and Maldacena, on a doubly periodic domain. The governing equations are of the BPS type and derived by Auzzi and Kumar in the mass-deformed framework labeled by a continuous parameter. Our method is based on fixed point method.

• 천문학논총
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• 제17권1호
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• pp.11-14
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• 2002

Our examination of the relations of spherically symmetric accretion on a massive point object to viscous drag, neglecting gas pressure and using self-similar transformation, shows the behaviors of the asymptotic solutions? in the regions near to and far from the center. The viscosity reduces the free-fall velocity by the factor $(1\;+\;\zeta) ^{-1}$, and causes flattening in the density distribution. Therefore, the viscosity leads to the reduction of the mass accretion rate.

• 한국항공우주학회지
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• 제36권10호
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• pp.996-1002
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• 2008

본 논문에서는 3차원 일대일 충돌 감지, 충돌 회피 및 경로점 유도를 위한 알고리듬에 대해 다룬다. 항공기는 질점 모델로 가정하였다. 충돌 감지는 최근접점까지 남은 시간과 그 때의 거리를 기준 값과 비교하여 수행하였다. 충돌 회피는 최적 제어 이론을 이용하여 최종 시간에서의 상대 거리를 최대화하는 가속도 입력을 계산하여 수행하였다. 경로점 유도는 잘 알려진 비례항법유도를 적용하였다. 제안된 알고리듬의 성능은 두 개의 시나리오를 통하여 검증하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제21회 추계학술대회 논문집
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• pp.31-34
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• 2003

가압방식 로켓추진기관시스템의 작동점 변화 추적을 위하여 각 추진제 탱크의 압력, 수위 및 비행 가속도로부터 각 추진제질유량, 연소실압력을 계산할 수 있는 직접상사모델을 만들었다. KSR-III의 비행시험결과 예로 분석하였으며, 이 계산모델을 통하여 가압방식 로켓추진시스템의 작동점 변화의 경향성을 파악할 수 있음을 보였다.

• 한국대기환경학회지
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• 제25권2호
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• pp.154-166
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• 2009

In this study, 1-hour integrated $PM_{2.5}$ mass and chemical composition concentrations were monitored at the St. Louis-Midwest Supersite in Illinois. Time-resolved samples were collected one week in each of June 2001 (22 June to 28 June), November 2001 (7 November to 13 November), and March 2002 (19 March to 25 March). A total of 427 samples were collected by CAMM (continuous ambient mass monitor) and 15 compounds were analyzed by AAS, PILS (particle-into-liquid sampler), and TOT (thermal optical transmittance) method. PMF was applied to identify the sources and apportion the $PM_{2.5}$ mass to each source for highly time resolved data. In addition, the nonparametric regression (NPR) was applied to identify the predominant directions of local sources relative to wind direction. Also, this study performed compare the NPR analysis and location of actual local point sources at the St. Louis area. The PMF modeling identified nine sources and the average mass was apportioned to gasoline vehicle, road dust, zinc smelter, copper production, secondary sulfate, diesel emission, secondary nitrate, iron+steel, and lead smelter, respectively. These results suggested that this study results will be help for $PM_{2.5}$ source apportionment studies at similar metropolitan area, establish $PM_{2.5}$ standard, and establish effective emissions reduction strategies in Korea.

• Journal of Radiation Protection and Research
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• 제21권3호
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• pp.217-253
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• 1996

체르노빌 핵사고직후 대형 핵사고에 대한 반응은 이 사고가 정치, 경제 및 사회적 요인에 밀접하게 관련된 대중정보에 어떻게 영향을 주는가의 극명한 사례가 되었다. 오늘날 다양한 정보화 시대에 살면서도 '핵'에 관한 한 정보원의 수용은 항상 제한 받는 경향에 있다. 그러므로 본 조사에서는 보도원으로부터 수용된 미확인보도 내지는 과장된 핵사고 상황보도 등의 문제로 파급될 수 있는 심리적인 동요와 혼란을 극소화할 수 있는 방법과 대책을 모색하여 개연성(probability)이 상존하는 크고 작은 핵사고의 경우에 대비코자 하는 한 사례로 삼고자 하였다. 또한, 핵사고시 제시된 방사선 제반분야에 대한 총망라된 보도영역에서 과학기사 보도 작성지침으로서의 관련 학술용어의 가능한 사용한도를 표로써 설정하였고, 아울러 본질적인 면에서 본 국민이해와 방사선 재해방지 홍보대책과 더불어 몇 가지 방법론을 거론하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권7호
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• pp.4141-4149
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• 2013

Background: Mammography is considered the gold standard of breast cancer mass screening and many countries have implemented this as an established breast cancer screening strategy. However, although the incidence of breast cancer and racial characteristics are different between Western and Asian countries, many Asian countries adopted mammography for mass screening. Therefore, the objective of this research was to determine whether mammography mass screening is cost-effective for both Western and Asian countries. Materials and Methods: A systematic review was performed of 17 national mammography cost-effectiveness data sets. Per capita gross domestic product (GDP), breast cancer incidence rate, and the most optimal cost-effectiveness results [cost per life year saved (LYS)] of a mammography screening strategy for each data set were extracted. The CE/per capita GDP ratio is used to compare the cost-effectiveness of mammography by countries. Non-parametric regression was used to find a cut-off point which indicated the breast cancer incidence rate boundary line determining whether mammography screening is cost-effective or not. Results: We found that the cost-effective cut-off point of breast cancer incidence rate was 45.04; it exactly divided countries into Western and Asian countries (p<0.0014). Conclusions: Mammography screening is cost-effective in most of Western countries, but not in Asian countries. The reason for this result may be the issues of incidence rate or racial characteristics, such as dense breast tissue. The results indicate that mammography screening should be adopted prudently in Asian countries and other countries with low incidence rates.

• 천문학회보
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• 제42권1호
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• pp.44.1-44.1
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• 2017

The single lens event OGLE-2015-BLG-1482 has been simultaneously observed from two ground-based surveys and from Spitzer. The Spitzer data exhibit finite-source effects due to the passage of the lens close to or directly over the surface of the source star as seen from Spitzer. Thanks to measurements of the microns parallax and the finite-source effect, we find that the lens of OGLE-2015-BLG-1482 is a very low-mass star with the mass $0.10{\pm}0.02M{\odot}$ or a brown dwarf with the mass $55{\pm}9MJ$, which are respectively located at $DLS=0.80{\pm}0.19kpc$ and $DLS=0.54{\pm}0.08kpc$, and thus it is the first isolated low-mass microlens that has been located in the Galactic bulge. The degeneracy between the two solutions is severe. The fundamental reason for the degeneracy is that the finite-source effect is seen only in a single data point from Spitzer and this single data point gives rise to two ${\rho}$ solutions.

• Imaging Science in Dentistry
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• 제36권2호
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• pp.95-101
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• 2006

Purpose : Bony strength is dependent on bone mass and bony structure. So this study was designed to investigate the relationship between the bone mass and bony trabecular characteristics. Subjects and Methods : Study subjects were 51 females (average age 68.6 years) and 20 males (average age 66.4 years). Bone mineral density (BMD, $grams/cm^2$) of proximal femur was measured by a dual energy X-ray absorptiometry (DEXA). Regions of interest (ROIs) were selected from the digitized radiographs of proximal femur. A customized computer program processed morphologic operations (MO) of ROIs. 44 skeletal variables of MO were calculated from ROIs on the Ward's triangle and greater trochanter of femur. WHO BMD classes were predicted by MO variables of the same ROI. Classification and Regression Tree analysis was used for calculating weighted kappa values, sensitivity and specificity of MO. Results : The discriminating factors of morphologic operation were branch point, branch point [per cm sq]. Age also played important role in distinguishing osteoporotic classes. The sensitivity of MO at Ward's triangle and Greater Trochanter was 91.8%, 65.6%, respectively. The specificity of MO was 100% at Ward's triangle and Greater Trochanter. Conclusion : Bony trabecular characteristics obtained using radiological bone morphometric analysis seem to be related to bone mass.

• 대한토목학회논문집
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• 제33권2호
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• pp.655-666
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• 2013

본 연구에서는 미고결 퇴적암을 통과하는 국내 최초 터널현장을 대상으로 시공현장의 시추코어를 이용하여 정량적인 슬레이크 내구성 시험과 점하중 강도시험을 통하여 미고결 퇴적암에 대한 정량적인 평가 방법을 제시하고 고결 정도에 따른 적절한 굴착 및 보강방법 등을 제안하고자 한다. 슬레이크 내구성 지수의 경우 3-cycle에서 변화량이 수렴되어 내구성을 구분하는 기준으로 $Id_3$ 값을 사용함이 합리적인 것으로 분석되었으며, 미고결 퇴적암의 $Id_3$ 평균값은 71.80, 점하중 시험결과 평균 일축압축강도 값은 10.8 MPa로 측정되었다. 실험 결과를 분석하여 일축압축강도, 고결상태, 막장확인, 습윤상태, 슬레이크 내구성 지수($Id_3$)를 포함하고 있는 미고결 퇴적암 터널 시공 시 적용 가능한 암반분류 기준을 제안하였다. 또한, 미고결 퇴적암 터널에 적합한 3가지 유형의 지보패턴을 제시하였고, 이는 시공 중인 터널의 내공변위 계측자료를 분석하여 적정성을 검토하였다.