• 천문학회지
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• 제35권4호
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• pp.175-185
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• 2002

Almost half of primeval galaxies show P-Cygni type profiles in the Ly$\alpha$ emission line. The main underlying mechanism for the profile formation in these systems is thought to be the frequency re-distribution of the line photons in expanding scattering media surrounding the emission source. A Monte Carlo code is developed to investigate the Ly$\alpha$ line transfer in an optically thick and moving medium with a careful consideration of the scattering in the damping wings. Typical column densities and expansion velocities of neutral hydrogen investigated in this study are $N_{H1}{\~}10^{17-20}\;cm^{-2}$ and ${\Delta}V{\~} 100 km\;s^{-1}$. We investigate the dependence of the emergent profiles on the kinematics and on the column density. Our numerical results are applied to show that the damped Ly$\alpha$ absorbers may possess an expanding H I supershell with bulk flow of ${\~}200 km\;s^{-l}$ and H I column density $N_{H1}{\~}10^{19}\;cm^{-2}$. We briefly discuss the observational implications.

• 물과 미래
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• 제25권3호
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• pp.65-77
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• 1992

본 연구의 목적은 기존에 발표된 이력현상 모형들을 분류하여 각 모형들의 특징을 비교하고 새로운 이력현상 모형의 형태에 대해 논하고자 한다. 기존에 발표된 이력현상 모형은 내삽모형, 축척모형과 영역모형으로 대별되며, 그중 영역모형만이 이론적 배경을 가지고 있다. 모형의 보정을 위해 한 개의 주곡선의 자료가 필요한 기존의 모형들의 타당성을 검증하기 위하야 Rubicon Sandy Loam과 Dune Sand의 실측자료와 비교하여 본 겨롸, 이들 모형들은 실측자료를 잘 모사할 수 없음을 알 수 있었다. 따라서 새로운 모형의 형태의 가능성을 종속여역모형에서 찾을수 있으며, 종속영역모형주에서도 순수한 매체에 대해 공극으로 공기의 진입에 대한 이웃하는 공극들의 방해효과의 정도를 설명하는 가중치를 도입한 모형(Model III-1, Mualem, 1984)을 단순화시키기 위해 이 모형에 적절한 가정을 부가한 형태의 모형이 새로운 형태의 모형에 대한 하나의 대안이 될 수 있음을 본 연구는 제시하고 있다.

• 한국수소및신에너지학회논문집
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• 제17권4호
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• pp.403-408
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• 2006

The plate reformer consisting of combustion chamber and reforming chamber for 25 kW MCFC stack has been operated and computational fluid dynamics was applied to estimate reactions and thermal fluid behavior in the reformer. The methane air 2-stage reaction was assumed in the combustion chamber, and three step steam reforming reactions were included in the calculation. Flow uniformity, reaction rate and species distribution, and temperature distribution were analyzed. In particular, temperature distribution was compared with the measurements to show good agreement in the combustion chamber, however, inappropriate agreement in the reformer chamber.

• 한국화재소방학회논문지
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• 제9권1호
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• pp.10-19
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• 1995

Study on combined natural convection-radiation In partially open square enclosures filled with absorbing-anisotropic scattering media is performed. A heater block located in the enclosure causes the natural circulation of the fluid in the enclosure which results In significant in-flow of the cold fluid through the partially open wall. Four different locations of the heater are considered to observe the effect of the heater locations on the resulting heat transfer. Results obtained from the combined convection-radiation analyses show much stronger circulation of t he fluid inside the enclosure as compared to those obtained from the pure convection analyses. As the ratio of the open area is Increased, the inflow of the cold fluid and the circulation of the fluid inside the enclosure is increased causing lower fluid temperature Inside the enclosure. It is shown that the location of the heater influences the circulation and heat transfer significantly by showing stronger circulations and more uniform temperature distributions for the cases where the heater is located on the bottom wall as compared to those for the cases where the heater is located on the upper part wall of the enclosure. For pure absorbing medium, the expected circulation in the fluid is relatively week as compared to those with absorbing-scattering medium due to the smaller wall heating as the radiant heat is used to heat the fluid instead. The forward anisotropic scattering phase function is shown to increase the fluid circulation further as compared to the isotropic scattering medium.

• 한국IT서비스학회지
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• 제13권4호
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• pp.275-287
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• 2014

Recently, the volume of unstructured text data generated by various social media has been increasing rapidly; consequently, the use of text mining to support decision-making has also been growing. In particular, academia and industry are paying significant attention to topic analysis in order to discover the main issues from a large volume of text documents. Topic analysis can be regarded as static analysis because it analyzes a snapshot of the distribution of various issues. In contrast, some recent studies have attempted to perform dynamic issue tracking, which analyzes and traces issue trends during a predefined period. However, most traditional issue tracking methods have a common limitation : when a new period is included, topic analysis must be repeated for all the documents of the entire period, rather than being conducted only on the new documents of the added period. Additionally, traditional issue tracking methods do not concentrate on the transition of individuals' interests from certain issues to others, although the methods can illustrate macro-level issue trends. In this paper, we propose an individual interests tracking methodology to overcome the two limitations of traditional issue tracking methods. Our main goal is not to track macro-level issue trends but to analyze trends of individual interests flow. Further, our methodology has extensible characteristics because it analyzes only newly added documents when the period of analysis is extended. In this paper, we also analyze the results of applying our methodology to news articles and their access logs.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.163-166
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• 2002

The concurrent injection of cosolvent and air, a cosolvent-air (CA) flood was recently suggested for a dense nonaqueous phase liquid (DNAPL) remediation technology. The objectives of this study were to elucidate the DNAPL removal mechanisms of the CA flood and to quantify mass transfer rate coefficients during CA flooding. DNAPL removal mechanisms were examined by evaluating the effects of air flow rate and DNAPL solubility and visually documented at a pore-scale. Two serial processes, immiscible displacement and dissolution, were experimentally and visually documented during CA flooding. Mass transfer rate coefficients (K) were computed from the data showing PCE saturation versus time. Results showed that CA floods exhibited higher K values than cosolvent floods without concurrent air injection. (This document has not been subjected to Agency review and therefore does not necessarily reflect the views of the Agency, and no official endorsement should be inferred.)

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1221-1227
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• 2011

Ethyl pyruvate (EP) is known as a scavenger of reactive oxygen species (ROS) in the body through its role in the donation of diketone groups to metals to form an EP-metal complex. In order to develop a method for the quantification of EP in biological media, a sensitive and specific, high-performance liquid chromatographyelectrospray ionization-mass spectrometry (HPLC-ESI/MS) method is used to determine the EP-alkali metal ion binding species. The analyte was separated on a ZORBOX SB-C8 ($3.5{\mu}m$, $30mm{\times}2.1mm$ I.D.) column and analyzed in selected ion monitoring (SIM) mode with a positive ESI interface using the m/z 255 $[2M + Na]^+$ ion. The method was validated over the concentration range of $0.5-60.0\;{\mu}g$/mL under 1/9 (v/v) of acetonitrile/methanol solvent system with flow rate 0.05 mL/min. The limit of quantification (LOQ) was $0.5{\mu}g$/mL.

• 한국실내디자인학회논문집
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• 제10호
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• pp.77-81
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• 1997

The study is for interior design and planning of new c conceptual modern shop(called "Value Conscious Store") t through the history of retail store, and its process is based on m most great cites in USA. The Value Conscious Store has c come into existence for consumer and retailer who have had v various lifestyles and characters. From analysis of new l lifestyle consumer to retailer's strategy. we could find i interesting design solutions and, forecast next concerns for d designing store. Store has been designed up-scaled and opened to give pleasure and comfort and made by a theme to m make unique and strong impact for customers. Also it uses M Multi-Media for excitment, and is designed as exhibition of m museum to lead constomers to new culture and trend. From t these interior trends will go on to next generation with new c concepts : environment and nature, senses and sensibility. T These words will be the new solution for creative and s successful store design by the designer who has environm mentally conscious and social responsibility in his mind. his mind.

• 한국환경복원기술학회지
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• 제10권3호
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• pp.1-7
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• 2007

For waste water treatment, artificial wetland was constructed in 1998. The size of artificial wetland is 20m${\times}$200m, with sand and gravel as media and Phragmites japonica was implanted. The removal rate of BOD, TN, and TP were 86%, 33% and 25% from June 2004 to November 2005 respectively, while those were 88%, 38% and 55% in 1999. Organic materials and nitrogen compounds are still effectively removed, after 6 years of construction, but the removal efficiency of phosphorus compounds is reduced. So for sustaining of artificial wetland as waste water treatment system, the removal efficiency of phosphorus compounds must be elevated.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2008년도 한국컴퓨터종합학술대회논문집 Vol.35 No.1 (B)
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• pp.261-264
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• 2008

본 논문에서는 영상의 중요한 특징을 강조하는 점의 분포를 가지는 자동화된 점묘화(stippling) 제작 방법을 제시한다. 예술가의 점묘화 일러스트 작품을 살펴보면 영상의 특징을 강조하는 방향성이 있는 점들을 사용해서 회화적인 느낌을 살림과 동시에 사물의 형태를 좀 더 명백히 파악할 수 있게 해준다. 하지만 컴퓨터 그래픽스 분야에서 연구된 기존 점묘화 기법 알고리즘은 입력 영상의 특징적인 형태를 고려하지 않고 색조에 따른 점의 밀도 변화만으로 사물을 표현하기 때문에 사물의 형태가 제대로 드러나지 않는 단점이 있다. 본 방법에서는 점의 분포가 대상의 형태를 반영하며 분포되게 하는 알고리즘을 적용하여 사물의 특징적인 형태를 강조한다. 이를 위해 영상의 특징선으로부터 추출한 특징 흐름(feature flow)을 따라 점을 배치시키는 방법을 사용한다. 그리고 입력 영상의 색조(tone)를 점묘화에 반영하기 위해 점의 크기가 입력 영상의 색조에 따라 자동으로 결정되도록 한다.