• 기술혁신학회지
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• 제8권3호
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• pp.887-910
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• 2005

This paper attempts to approximate the distribution function for the number of innovation activities (NIA). To this end, the dataset of 2002 Korean Innovation Survey (KIS 2002) published by Science and Technology Policy Institute is used. To deal with zero NTI values given by a considerable number of firms in the KIS 2002 survey, a mixture model of distributions for NIA is applied. The NIA is specified as a mixture of two distributions, one with a point mass at zero and the other with full support on the positive half of the real line. The model was empirically verified for the KIS 2002 data. The mixture model can easily capture the common bimodality feature of the NIA distribution. In addition, when covariates were added to the mixture model, it was found that the probability that a firm has zero NIA significantly varies with some variables.

• 천문학회보
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• 제39권1호
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• pp.27-27
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• 2014

The past three decades have witnessed a renaissance in the field of extragalactic globular clusters (GCs). GC systems have now been investigated in galaxies ranging from dwarfs to giants and spanning all the morphological types. Detailed studies of GCs provide strong constraints on galaxy formation that can be obtained in the near-field. In this talk I will review some of the pivotal studies performed with the HST and large ground-based telescopes and state-of-the-art simulations. Also, I will attempt to introduce my new solution to a long-standing puzzle in this field----the origin of GC bimodality in color. I will show that the theory gives a simple, cohesive explanation for the key observations of extragalactic GCs. The implication of the results will be discussed in the context of formation of GC systems and their parent galaxies.

• 자원ㆍ환경경제연구
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• 제11권2호
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• pp.321-333
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• 2002

Approximating bottled water consumption distribution is complicated by zero observations in the sample. To deal with the zero observations, a mixture model of bottled water consumption distributions is proposed and applied to allow a point mass at zero. The bottled water consumption distribution is specified as a mixture of two distributions, one with a point mass at zero and the other with full support on the positive half of the real line. The model is empirically verified for household bottled water consumption survey data. The mixture model can easily capture the common bimodality feature of the bottled water consumption distribution. In addition, when covariates were added to the model, it was found that the probability that a household has non-consumption significantly varies with some variables.

• 천문학회보
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• 제40권1호
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• pp.46.1-46.1
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• 2015

M85 is a merger remnant galaxy in the Virgo Cluster, showing complex merging features. Globular clusters in M85 are a good tracer of its merging history. To investigate globular cluster system of M85, we obtain deep and wide field images of M85 in ugi filters covering one square degree using CFHT/MegaCam. We discover about 1,000 globular cluster candidates in these images. The color distribution of the globular cluster candidates within r < 5' from M85 does not show a clear bimodality and blue globular cluster candidates are more than red ones. These features are different from those in massive early-type galaxies. The spatial distribution of the globular cluster candidates is elongated along the faint stellar light of M85. We also investigate the spatial distribution of sub-populations of the globular cluster candidates with different color and brightness and estimate their ages based on their color. We discuss these results in relation with the formation history of M85.

• 에너지공학
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• 제23권3호
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• pp.36-41
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• 2014

The world's overall need for natural gas (NG) has been growing up fast, especially in the residential sector. The better the estimation of residential NG consumption (RNGC) distribution, the better decision-making for a residential NG policy such as pricing, demand estimation, management options and so on. Approximating the distribution of RNGC is complicated by zero observations in the sample. To deal with the zero observations by allowing a point mass at zero, a mixture model of RNGC distributions is proposed and applied. The RNGC distribution is specified as a mixture of two distributions, one with a point mass at zero and the other with full support on the positive half of the real line. The model is empirically verified for household RNGC survey data collected in Korea. The mixture model can easily capture the common bimodality feature of the RNGC distribution. In addition, when covariates were added to the model, it was found that the probability that a household has non-expenditure significantly varies with some variables. Finally, the goodness-of-fit test suggests that the data are well represented by the mixture model.

• 천문학회지
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• 제43권4호
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• pp.105-113
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• 2010

We study the dynamical evolution of the M87 globular cluster (GC) system using the most advanced and realistic Fokker-Planck (FP) model.By comparing our FP models with both mass function (MF) and radial distribution (RD) of the observed GC system, we find the best-fit initial (at M87's age of 2-3 Gyr) MF and RD for three GC groups: all GCs, blue GCs, and red GCs. We estimate the initial total mass in GCs to be $1.8^{+0.3}_{-0.2}{\times}10^{10}M_{\bigodot}$, which is about 100 times larger than that of the Milky Way GC system. We also find that the fraction of the total mass currently in GCs is 34\%. When blue and red GCs are fitted separately, blue GCs initially have a larger total mass and a shallower radial distribution than red GCs. If one assumes that most of the significant major merger events of M87 have ended by the age of 2-3 Gyr, our finding that blue (metal-poor) GCs initially had a shallower radial distribution supports the major merger scenario for the origin of metallicity bimodality.

• Journal of Pharmaceutical Investigation
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• 제9권3호
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• pp.1-8
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• 1979

The main route of metabolism of isonicotinic acid hydrazid (INH) in man is its conjugation with acetyl coenzyme A to form acetyl-INH. The reaction is catalyzed by an N-acetyl transferase in the liver. The acetylated drug can be excreted by the kidney more efficiently than INH, and the biological half-life of the drug in the body depends upon how rapidly the drug can be acetylated. This report measured the concentration of INH in the blood of 147 individuals 6 hours after they received a standard dose (9.8mg/kg) and plotted the data as a frequeney distribution hiotogram. There was bimodality, with a mean for one subpopulation at approximately $0.6{\sim}0.8\;mcg/ml.$, and a mean for the other subpopulation between 2.8 and 4.0mcg/ml. As might be expected slow acetylators of INH are more likely to develop a cumulative toxicity to the drug. The principle ,toxicity to INH is a peripheral neuritis but this adverse effect can be prevented by given extra pyridoxin to the patients, and the vitamin does not alter the antitubercular activity of INH. This report carried out that pyridoxine does not alter the ratio of free INH to the total INH in blood.

• 천문학회보
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• 제39권2호
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• pp.69.2-69.2
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• 2014

We present space-based near-IR (NIR) and optical photometry of globular clusters (GCs) of 16 early-type galaxies in the Fornax and Virgo Clusters. The NIR imaging data for the nearby galaxies was acquired with the IR Channel of the Wide Field Camera 3 (WFC3/IR) in the F110W ($J_{110}$) and F160W ($H_{160}$) bandpasses. We introduce the full sample of our WFC3/IR program, describe data reductions and photometric measurements including GC candidate selection criteria, and then show selected GCs' color-magnitude diagrams. The tilted features in the diagrams related to the morphological types of host galaxies are discussed in the context of galaxy formation and evolution histories. Combining F475W ($g_{475}$) and F850LP ($z_{850}$) data taken from the Advanced Camera for Surveys Virgo and Fornax Cluster Surveys with our NIR data, we investigate the bimodality in optical-NIR color distribution and the nonlinear feature of the optical-NIR color relation as a function of optical color for these extragalactic GC systems.

• 천문학회보
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• 제35권2호
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• pp.31.2-31.2
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• 2010

We have performed a spectroscopic study of globular cluster (GC) system associated with the Virgo cD galaxy M87 using the Subaru/FOCAS MOS mode. We derive ages, metallicities and abundance ratios from the GC spectra using Simple Stellar Population (SSP) models. The metallicity distribution function (MDF) obtained empirically based on Milky Way GCs is consistent with the MDF derived from SSP models. A comparison with a meta-analysis using literature data sample of 15 other GC systems shows good agreement with our results. The properties of GCs acquired from the spectra will be used to test the recent theoretical prediction of a significant inflection along the colour-metallicity relations (Yoon et al. 2006). If confirmed, the non-linearity of the relations would shed new light on the interpretation of the GC colour bimodality. The robustness of our results is being tested against the choice of a SSP model, measurement errors and sample selection towards the goal of better understanding the formation history of GCs and host galaxy.

• 한국동물학회지
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• 제5권1호
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• pp.13-20
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• 1962

1. 1957년 8월 7일부터 18일까지 계룡산에서 고도차분포를 조사하기 위하여 고도별 4 지점에서 과물 (복숭아, 도마도) trap를 사용하여 오전 6시와 오후 6시에 동시에 초파리를 채집하였다. 그리고 sweeping 도 하여 총 33 종을 채집하였는데 다음종들은 높은 지점에서 발견되었다. Microdrosophila purpurata, Mycodrosophila basalis, Parascaptomyz disticha, Scaptomyza aplicalis , Drosophila histrioides, D.difasciata, D.histrio. 그리고 초파리의 성비가 고도에 따라 변동하였음을 관찰하였는데 특히. D. suzukii 는 저지에서 충이 현저히 많았던 것이 700미 고지에서는 거의 1 : 1의 성비를 보여주었다. 300 미높이의 (B) 지점에서 D.lacertosa 와D. Coracina 의 일주기활동은 반대적이었는데 D.lacertosa 는 습도가 높은 아침에 주로 활동하고, D.coracina는 이와 반대로 주로 오후에 활동하고 있음을 알았다. 2. 초파리 집단의 계절적 변동을 조사하기 위하여 1958년 4월부터 11월까지 매일 중순삼일씩 공주잠업시험소구내 상전에서 그리고 동년 5월 터 11월까지는 매일 초순삼일식 계룡산에서 각각 5개의 과물 trap를 설치하고 비교관찰하엿따. 매월 초파리종들의 계절적 변동은 3 표와 4 표에 기재된 바와같다. 특히 D.auraria는 두장소에서 우점종이었는데 공주잠업시험소구내 상전에서는 9월에 최고에 달했고, 계룡산에서는 8월에 최고에 달하는 unimodality를 표시하였다. 3 . 초파리의 일주기활동을 조사하기 위하여1959년 6월부터 10월까지 공주잠업시험소구내 상전에서 매월 2일간씩 2시간마다 채집을 하였다. 이 지방에서 우점종인 D.auraria 는 매월 일주기활동에 있어서 bimodality를 형성하였는데 9, 10월에는 두 peak는 서로 근접되었다. 그리고 6월 26일 2시간마다 sweeping 법으로 채집한 D.auraria의 일주기활동도 비교연구하였는데 거의 같은 현상을 나타냈다.