• 대한지리학회지
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• 제30권2호
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• pp.120-131
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• 1995

이동행태를 분석하기 위해 시.공간이론 중 3가지 제약조건인 능력제약, 조합제약, 권위제약이 공간특성에 따라 성별, 연령이 이동에 어느 정도 영향을 주는지를 분석하고 적 정 이동군집수를 결정하고자 한다. 이중 권위제약은 사회적 제약조건으로서 도시시설물이나 교통수단의 이용에 있어 사회적 신분이나 규약에 의해 이동영역이 통제되는 것을 의미한다. 공간특성에 의한 이동의 통제는, 도시와 농촌으로 구분하였을 때 도시지역 사람들은 농촌지 역 사람들에 비해 첨두시간대의 이동 참여율이 높으며, 이동군집수 결정에 있어서도 여러 연령층이 유사한 이동행태를 지니고 있음을 알 수 있다. 도시지역 사람들은 공간특성상에 따른 이동의 다양성이 군집수 결정에 상관되었으며, 이는 공간특성에 따라 이동행태가 달라 질 수 있다고 볼 수 있다. 성별 및 연령에 의한 통제 역시 사회적 제약조건으로서 이동행태 에 영향이 있음을 알 수 있다.

• 천문학회보
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• 제41권2호
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• pp.44.1-44.1
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• 2016

The Sagittarius-Carina spiral arm in the Galaxy contains several massive young open clusters. We present a deep optical photometric study on the massive young open clusters in the Sagittarius-Carina arm, Westerlund 2 and the young open clusters in the ${\eta}$ Carina nebula. Westerlund 2 is a less studied starburst-type cluster in the Galaxy. An abnormal reddening law for the intracluster medium of the young starburst-type cluster Westerlund 2 is determined to be $R_{V,cl}=4.14{\pm}0.08$. The distance modulus is determined from zero-age main-sequence fitting to the reddening-corrected color-magnitude diagrams of the early-type members to be $V_0-M_V=13.9{\pm}0.14mag$. The pre-main sequence (PMS) members of Westerlund 2 are selected by identifying the optical counterparts of X-ray emission sources from the Chandra X-ray observation and mid-infrared emission sources from the Spitzer/IRAC (the Infrared Array Camera) observation. The initial mass function (IMF) shows a slightly flat slope of ${\Gamma}=-1.1{\pm}0.1$ down to $5M_{\odot}$. The age of Westerlund 2 is estimated to be. 1.5 Myr from the main-sequence turn-on luminosity and the age distribution of PMS stars. The ${\eta}$ Carina nebula is the best laboratory for the investigation of the Galactic massive stars and low-mass star formation under the influence of numerous massive stars. We have performed deep wide-field CCD photometry of stars in the ${\eta}$ Carina nebula to determine the reddening law, distance, and the IMF of the clusters in the nebula. We present VRI and $H{\alpha}$ photometry of 130,571 stars from the images obtained with the 4m telescope at Cerro Tololo Inter-American Observatory (CTIO). RV,cl in the η Carina nebula gradually decreases from the southern part (~4.5, around Trumpler 14 and Trumpler 16) to the northern part around Trumpler 15 (~3.5). Distance to the young open clusters in the ${\eta}$ Carina nebula is partly revised based on the zero-age main-sequence fitting to the reddening-corrected color-magnitude diagrams (CMDs) and the (semi-) reddening-independent CMDs. We select the PMS members and candidates by identifying the optical counterparts of X-ray sources from the Chandra Carina Complex Survey and mid-infrared excess emission stars from the Spitzer Vela-Carina survey. From the evolutionary stage of massive stars and PMS stars, we obtain that the northern young open cluster Trumpler 15 is distinctively older than the southern young open clusters, Trumpler 14 (${\leq}2.5 Myr$) and Trumpler 16 (2.5-3.5 Myr). The slopes of the IMF of Trumpler 14, Trumpler 15, and Trumpler 16 are determined to be $-1.2{\pm}0.1$, $-1.5{\pm}0.3$, and $-1.1{\pm}0.1$, respectively. Based on the RV,cl of several young open clusters determined in this work and the previous studies of our group, We suggest that higher RV,cl values are commonly found for very young open clusters with the age of < 4 Myr. We also confirm the correlation between the slope of the IMF and the surface mass density of massive stars.

• 한국경제지리학회지
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• 제26권3호
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• pp.238-255
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• 2023

본 연구는 클러스터의 특성요인을 측정할 수 있는 변수로 도출하여, 창신동, 독산동, 장위동 의류봉제 집적지의 특성을 밝히고자 하였다. 이 결과를 토대로 각 집적지별로 정부의 지원정책에 대한 수요가 어떻게 다른지를 비교분석하였다. 자료는 세 지역의 입주업체를 대상으로 한 대면 설문조사와 심층인터뷰를 통해 수집하였다. 분석결과, 창신동은 '혁신성장 지향형', 독산동은 '네트워킹 지향형', 그리고 장위동은 '전문집적 지향형', 클러스터로 판별되었다. 정책수요에 대한 조사 결과 세 지역의 정책수요가 다르게 나타났는데, 창신동은 역량형성, 독산동은 정보제공, 장위동은 혜택의 정책수단을 선호하였다. 동일한 의류봉제 업종의 집적지 간에도 형성과정과 특성이 다르고, 그로 인해 정책수단에 대한 수요도 다르다는 것을 확인할 수 있었다. 정책적 제언으로는 주기적인 실태조사를 통한 집적지별 특성과 정책수요의 파악, 집적지의 특성에 부합하는 차별화된 지원정책의 수립과 집행을 제언한다.

• Spatial Information Research
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• 제8권2호
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• pp.301-315
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• 2000

지반조사 자료는 구조물을 시공하거나 설계하기 위해 필요한 기본자료이며 지층의 구성, 토질의 종류 등 기반을 구별하는 정보를 포함한다. 매년 대량으로 발생하는 지반조사 자료들은 현장의 특성을 정확하게 반영하기 때문에 지반조사 자료를 이용하여 지반을 분석한다면, 기존의 지질도나 토양도보다 뛰어난 결과를 얻을 수 있다. 따라서 비균질하고 비정형화된 지반의 특성을 고려하여 서로구별하는 특징을 추출하고, 현장의 특성을 정확하게 반영하는 지반분석 시스템이 필요하다. 본 논문은 지반조사 정보 시스템이 관리하고 있는 시추공의 지층구성 정보와 위치 근접성을 바탕으로 시추공을 클러스터링하여 지반의 구성을 분석하는 지반분석시스템의 설계 및 구현에 대해 전반적으로 기술하였다. 개발된 지반분석시스템은 지반조사 데이터베이스의 시추공 정보를 이용하여 지반이 가지고 있는 특성 정보를 추출하고, 이를 이용하여 유사한 특성 및 위치 근접성을 갖는 시추공의 집합으로 클로스터링하여 사용자에게 정확한 지반구성 정보를 제공하는 시스템이다. 또한, 수치지도의 사용으로 지리적 위치와 지역·지형에 대한 지반구조의 특성조사를 가능하게 하며, 지반조사를 필요로 하는 지역에 대한 지반의 유추가 가능하여 경제적 효과를 볼 수 있다. 따라서, 지반조사 데이터로부터 다양한 종류의 정보를 얻을 수 있으며 지질도나 토양도보다 정확한 지반특성을 제공할 수 있다.

• 천문학회지
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• 제50권3호
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• pp.51-59
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• 2017

The presence of blue stragglers pose challenges to standard stellar evolution theory, in the sense that explaining their presence demands a complex interplay between stellar evolution and cluster dynamics. In the meantime, mass transfer in binary systems and stellar collisions are widely studied as a blue straggler formation channel. We explore properties of the Galactic open clusters where blue stragglers are found, in attempting to estimate the relative importance of these two favored processes, by comparing them with those resulting from open clusters in which blue stragglers are absent as of now. Unlike previous studies which require a sophisticated process in understanding the implication of the results, this approach is straightforward and has resulted in a supplementary supporting evidence for the current view on the blue straggler formation mechanism. Our main findings are as follows: (1) Open clusters in which blue stragglers are present have a broader distribution with respect to the Z-axis pointing towards the North Galactic Pole than those in which blue stragglers are absent. The probability that two distributions with respect to the Z-axis are drawn from the same distribution is 0.2%. (2) Average values of $log_10(t)$ of the clusters with blue stragglers and those without blue stragglers are $8.58{\pm}0.232$ and $7.52{\pm}0.285$, respectively. (3) The clusters with blue stragglers tend to be relatively redder than the others, and are distributed broader in colors. (4) The clusters with blue stragglers are likely brighter than those without blue stragglers. (5) Finally, blue stragglers seem to form in condensed clusters rather than simply dense clusters. Hence, we conclude that mass transfer in binaries seems to be a relatively important physical mechanism of the generation of blue stragglers in open clusters, provided they are sufficiently old.

• 전자공학회논문지CI
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• 제39권4호
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• pp.10-18
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• 2002

통신망 설계는 다양한 설계 인자들이 고려되는 다목적 함수 문제이다. 특히 망의 구성 비용, 메시지 지연 그리고 신뢰도는 망의 최대 효율을 얻는데 중요한 설계 인자이다. 최근 들어 유전자 알고리즘은 조합최적화 문제, 통신망 설계문제와 같은 현실적 문제를 위한 최적화 기법으로 널리 활용되어 지고 있다. 본 논문은 망의 구성비용과 메시지 지연시간을 최소화 하는 통신망 설계를 위한 다목적 유전 알고리즘을 제시한다. 본 알고리즘은 다목적 함수의 최적화에서 일반적으로 어려운 목적 함수간의 최적화를 위해 파레토를 이용하였다. 부호화 방법으로 프뤼퍼 숫자와 클러스터링 문자를 사용했고, 적합도 배분방법으로 파레토 순위할당 제거방법과 생태적 적소형태(niche-formation)방법을 사용하였으며, 조기수렴을 방지위해 변형된 엘리트 기법을 사용했다. 시뮬레이션을 통해 제안하는 알고리즘이 망구성의 후보해를 효과적으로 찾음을 보여준다.

• Ocean and Polar Research
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• 제34권2호
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• pp.111-123
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• 2012

To understand the phytoplankton community in the eastern part of the Yellow Sea (EYS), in the summer, field survey was conducted at 25 stations in June 2009, and water samples were analyzed using a epifluorescence microscopy, flow cytometry and HPLC method. The EYS could be divided into four areas by a cluster analysis, using phytoplankton group abundances: coastal mixing area, Anma-do area, transition water, and the central Yellow Sea. In the coastal mixing area, water column was well mixed vertically, and phytoplankton was dominated by diatoms, chrysophytes, dinoflagellates and nanoflagellates, showing high abundance ($>10^5\;cells\;l^{-1}$). In Anma-do coastal waters characterized by high dominance of dinoflagellates, high phytoplankton abundance and biomass separated from other coastal mixing area. The southeastern upwelling area was expanded from Jin-do to Heuksan-do, by a tidal mixing and coastal upwelling in the southern area of Manjae-do, and phytoplankton was dominated by benthic diatoms, nanoflagellates and Synechococcus group in this area. Phytoplankton abundance and biomass dominated by pico- and nanophytoplankton were low values in the transition waters and the central Yellow Sea. In the surface of the central Yellow Sea, high dominance of photosynthetic pigments, 19'-hexanoyloxyfucoxanthin and zeaxanthin implies that haptophytes and cyanobacteria could be the dominant group during the summer. These results indicate that the phytoplankton communities in the EYS were significantly affected by the formation of tidal front, thermal stratification, and coastal upwelling showing the differences of physical and chemical characteristics during the summer.

• 천문학회지
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• 제37권4호
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• pp.281-284
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• 2004

Optical imaging and spectroscopy of G353.2+0.9, the brightest part of the giant H II region NGC 6357, shows that this H II region is optically thin, contains ${\~}300\;M_{\bigodot}$ of ionized gas and is probably expanding into the surrounding medium. Its chemical composition is similar to that found in other H II regions at similar galactocentric distances if temperature fluctuations are significant. The inner regions are probably made of thin shells and filaments, whereas extended slabs of material, maybe shells seen edge-on, are found in the periphery. The radio continuum and H$\alpha$ emission maps are very similar, indicating that most of the optical nebula is not embedded in the denser regions traced by molecular gas and the presence of IR sources. About $10^{50}$ UV photons per second are required to produce the H$\beta$ flux from the 1l.3'${\times}$10' region surrounding the Pis 24 cluster that is south of G353.2+0.9. Most of the energy powering this region is produced by the 03-7 stars in Pis 24. Most of the 2MASS sources in the field with large infrared excesses are within G353.2+0.9, indicating that the most recent star forming process occured within it. The formation of Pis 24 preceded and caused the formation of this new generation of stars and may be responsible for the present-day morphology of the entire NGC 6357 region.

• Journal of Ginseng Research
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• 제41권4호
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• pp.456-462
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• 2017

Background: Abnormal activation of matrix metalloproteinases (MMPs) plays an important role in UV-induced wrinkle formation, which is a major dermatological problem. This formation occurs due to the degeneration of the extracellular matrix (ECM). In this study, we investigated the cutaneous photoprotective effects of Ultraflo L treated ginseng leaf (UTGL) in hairless mice. Methods: SKH-1 hairless mice (6 weeks of age) were randomly divided into four groups (8 mice/group). UTGL formulation was applied topically to the skin of the mice for 10 weeks. The normal control group received nonvehicle and was not irradiated with UVB. The UV control (UVB) group received nonvehicle and was exposed to gradient-UVB irradiation. The groups (GA) receiving topical application of UTGL formulation were subjected to gradient-UVB irradiation on $0.5mg/cm^2$ [GA-low (GA-L)] and $1.0mg/cm^2$ [(GA-high (GA-H)] of dorsal skin area, respectively. Results: We found that topical treatment with UTGL attenuated UVB-induced epidermal thickness and impairment of skin barrier function. Additionally, UTGL suppressed the expression of MMP-2, -3, and -13 induced by UVB irradiation. Our results show that topical application of UTGL protects the skin against UVB-induced damage in hairless mice and suggest that UTGL can act as a potential agent for preventing and/or treating UVB-induced photoaging. Conclusion: UTGL possesses sunscreen properties and may exhibit photochemoprotective activities inside the skin of mice. Therefore, UTGL could be used as a potential therapeutic agent to protect the skin against UVB-induced photoaging.

• 천문학회보
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• 제37권2호
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• pp.73.2-73.2
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• 2012

Matusoka & Kawara (2010) showed that the number density of the most massive galaxies (log $M/M_{\odot}=11.5-12.0$) increases faster than that of the next massive group (log $M/M_{\odot}=11.0-11.5$) during 0 < z < 1. This appears to be in contradiction to another important empirical concept of "downsizing". We attempt to understand the two observational findings in the context of the hierarchical merger paradigm using semi-analytic techniques. Our models closely reproduce the result of Matusoka & Kawara (2010). Downsizing can also be understood as larger galaxies have on average smaller assembly ages but larger stellar ages. Our fiducial models further reveal the details on the history of stellar mass growth of massive galaxies. The most massive galaxies (log $M/M_{\odot}=11.5-12.0$ at z=0), which are mostly brightest cluster galaxies, obtain roughly 70% of their stellar components via merger accretion. The role of merger accretion monotonically declines with galaxy mass: 45% for log $M/M_{\odot}=11.0-11.5$ and 20% for log $M/M_{\odot}=10.5-11.0$ at z = 0. The specific accreted stellar mass rates via galaxy mergers decline very slowly during the whole redshift range, while the specific star formation rates sharply decrease with time. In the case of the most massive galaxies, merger accretion becomes the most important channel for the stellar mass growth at z ~ 2. On the other hand, in-situ star formation is always the dominant channel in the $L_*$ galaxies.