• Title/Summary/Keyword: Star Models

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Historical Study of Glamour Style (글래머 스타일의 사적 고찰)

  • Park, Ju-Hee
    • The Research Journal of the Costume Culture
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    • v.16 no.2
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    • pp.382-396
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    • 2008
  • The purpose of this study is to analyze the transition of glamour style expressed in modern fashion throughout the history. The glamour style in modern fashion was categorized into five periods which are Hollywood glamour(H), Feminine glamour(F), Rich glamour(R), Decadent glamour(D), and Trash glamour(T). These categories were analyzed and compared in the viewpoint of aesthetic values deduced on the previous study. As a method of analysis, literature study and case study through the publications in aesthetics, history and preceding theses were used. The results of analysis are: Ostentatious luxury was suggested by extravagance of the movie star in H, the splendid American lifestyle in F, conspicuous consumption in R, fin de siecle bad taste in D and self-assured exposure in T. Mysterious idolatry was studied as exaggerated goddesshood of the movie star in H. It was expanded to celebrities including fashion models, television actresses, pop singers and young couture designers in the other periods. Artificial sensuality was originated from the femme fatale image of the courtesan as well as the traditional femininity of Victorian era in H. It was developed through exaggerated hourglass silhouette of the wife dressing in F. But an aggressiveness in R, a hyper-sexual femme fatale in D, an independent and defiant image of the showgirl in T were observed. Playful queerness stood out clearly by the fin de siecle phenomena. Though it was embodied in sexual perversive subculture, it emerged as hi fashion by young designers in the late R and became a crucial aesthetic value throughout D and T. It is more connected with the origins of glamour which arouses sexual ambiguity, crudity, aggressiveness and death. The continuity and discontinuity of the glamour style based on the theory of 'linked solution' were also analyzed.

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Intensive Monitoring Survey of Nearby Galaxies (IMSNG) : Constraints on the progenitor system of a normal Type Ia SN 2019ein from its light curve at the early phase

  • Lim, Gu;Im, Myungshin;Kim, Dohyeong;Paek, Gregory S.H;Choi, Changsu;Kim, Sophia;Hwang, Sungyong
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.1
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    • pp.55.2-56
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    • 2021
  • The progenitor of Type Ia supernovae (SNe Ia) is mainly believed to be a close binary system of acarbon-oxygen white dwarf (CO WD) and non-degenerate companion (single degenerate) or another WD (double degenerate). However, it is unclear which system is more prevalent. Here, we present a high cadence optical/Near-IR light curve of normal but slightly faint type Ia SN 2019ein from IMSNG project. We fit the early light curve (t <+8.3 days from the first detection) with various models to find the shock-heated cooling emission from SN ejecta-companion interaction. No significant shock-heated cooling emission is found, from which we constrain the progenitor star size as the following. The upper limit (Rupper,*) of the companion size in R-band is ~0.2R when forcing the first light time (tfl) to have one value and ~0.9R when using the mean value of tfl from the fitting in each band. Assuming the source of the I-band curve is almost powered from the radioactive decay, we obtained Rupper,*~1.2R. The early B-V color curve is in agreement with the model color curve of the 2M main sequence companion. These results allow us to at least rule out large stars like red giants as a companion star of the binary progenitor system of this supernova. B-R and V-R color do not show any significant signs of a red bump, which shows a thin helium shell (MHe<0.1M) for the sub-Mch WD (double detonation model). In addition, we estimated the distance to NGC 5353 as 37.098±0.028Mpc.

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F_MixBERT: Sentiment Analysis Model using Focal Loss for Imbalanced E-commerce Reviews

  • Fengqian Pang;Xi Chen;Letong Li;Xin Xu;Zhiqiang Xing
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.18 no.2
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    • pp.263-283
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    • 2024
  • Users' comments after online shopping are critical to product reputation and business improvement. These comments, sometimes known as e-commerce reviews, influence other customers' purchasing decisions. To confront large amounts of e-commerce reviews, automatic analysis based on machine learning and deep learning draws more and more attention. A core task therein is sentiment analysis. However, the e-commerce reviews exhibit the following characteristics: (1) inconsistency between comment content and the star rating; (2) a large number of unlabeled data, i.e., comments without a star rating, and (3) the data imbalance caused by the sparse negative comments. This paper employs Bidirectional Encoder Representation from Transformers (BERT), one of the best natural language processing models, as the base model. According to the above data characteristics, we propose the F_MixBERT framework, to more effectively use inconsistently low-quality and unlabeled data and resolve the problem of data imbalance. In the framework, the proposed MixBERT incorporates the MixMatch approach into BERT's high-dimensional vectors to train the unlabeled and low-quality data with generated pseudo labels. Meanwhile, data imbalance is resolved by Focal loss, which penalizes the contribution of large-scale data and easily-identifiable data to total loss. Comparative experiments demonstrate that the proposed framework outperforms BERT and MixBERT for sentiment analysis of e-commerce comments.

PMS EVOLUTION MODEL GRIDS AND THE INITIAL MASS FUNCTION

  • PARK BYEONG-GON;SUNG HWANKYUNG;KANG YONG HEE
    • Journal of The Korean Astronomical Society
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    • v.35 no.4
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    • pp.197-208
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    • 2002
  • Five contemporary pre-main sequence (PMS) evolution model grids are compared with the photo-metric data for a nearly complete sample of low-mass members in NGC 2264. From amongst the grids compared, the models of Baraffe et al. (1998) prove to be the most reliable in mass-age distribution. To overcome the limited mass range of the models of Baraffe et al. we derived a simple transformation relation between the mass of a PMS star from Swenson et al. (1994) and that from Baraffe et al., and applied it to the PMS stars in NGC 2264 and the Orion nebula cluster (ONC). The resulting initial mass function (IMF) of the ONC shows that the previous interpretation of the IMF is not a real feature, but an artifact caused by the evolution models adopted. The IMFs of both clusters are in a good agreement with the IMF of the field stars in the solar neighborhood. This result supports the idea proposed by Lada, Strom, & Myers (1993) that the field stars originate from the stars that are formed in clusters and spread out as a result of dynamical dissociation. Nevertheless, the IMFs of OB associations and young open clusters show diverse behavior. For the low-mass regime, the current observations suffer from difficulties in membership assignment and sample incompleteness. From this, we conclude that a more thorough study of young open clusters is necessary in order to make any definite conclusions on the existence of a universal IMF.

Research on Professional Groups through Learning of Professional Game Players (전문가 집단 양성을 위한 프로게이머 발달 및 학습 모형 연구)

  • Kim, Sa-Hoon H.;Park, Sang-Wook W.
    • Journal of Korea Game Society
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    • v.10 no.4
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    • pp.23-34
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    • 2010
  • The current interests in e-sports is being extended to the fields of education these days. Professional game players, so called as 'Pro-Gamers', therefore, should be recognized as human resource for education, and the theoretical foundation for them needs to be established. This study examines informal learning styles, motivation, and interactions among professional game players in South Korea. The aim of this grounded theory study is to discover the trajectory of professional game players' experiences and explain what properties and interactions they are facing depending on the stage of the trajectory. This study conceptualizes educational meaning within and across the society of StarCraft Pro-Gamers, providing suggestions for the management of human resource using models constructed. Data was analyzed by interviewing 1 consultant, 2 directors and 9 Pro-Gamers. By analyzing the data, this study explored what learning strategies Pro-Gamers construct and apply in their trajectory as Pro-Gamers. It includes how they organize learning, how they formulate their motivation and goals, how they cooperate and compete, what curricula they adapt, how they become one of the ace players overcoming their slump, and how informal education works in practice in the interaction among members of a StarCraft Pro-Gamer team. Finally, in this paper the stage theory was presented. It is argued that when the stage of the players shifts (Stage Shifting). It also brings changes to proficiency properties, emotional properties, interactional properties and educational properties related to each stage. Stages are categorized by five levels: Enjoying, Struggling, Achieving, Slumping, and Recovering. Although each stage has its own properties, the stages are grouped by two main properties, one of which is a Communicative Stage and the other is a Practicing Stage.

OGLE-2019-BLG-0362Lb: A SUPER-JOVIAN-MASS PLANET AROUND A LOW-MASS STAR

  • Chung, Sun-Ju;Yee, Jennifer C.;Udalski, Andrej;Gould, Andrew;Albrow, Michael D.;Jung, Youn Kil;Hwang, Kyu-Ha;Han, Cheongho;Ryu, Yoon-Hyun;Shin, In-Gu;Shvartzvald, Yossi;Zang, Weicheng;Cha, Sang-Mok;Kim, Dong-Jin;Kim, Seung-Lee;Lee, Chung-Uk;Lee, Dong-Joo;Lee, Yongseok;Park, Byeong-Gon;Pogge, Richard W.;Poleski, Radek;Mroz, Przemek;Pietrukowicz, Pawel;Skowron, Jan;Szymanski, Michal K.;Soszynski, Igor;Kozlowski, Szymon;Rybicki, Krzysztof A.;Iwanek, Patryk;Wrona, Marcin;Gromadzki, Mariusz;Ulaczyk, Krzysztof
    • Journal of The Korean Astronomical Society
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    • v.55 no.4
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    • pp.123-130
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    • 2022
  • We present the analysis of a planetary microlensing event OGLE-2019-BLG-0362 with a shortduration anomaly (~0.4 days) near the peak of the light curve, which is caused by the resonant caustic. The event has a severe degeneracy with ∆𝜒2 = 0.9 between the close and the wide binary lens models both with planet-host mass ratio q ≃ 0.007. We measure the angular Einstein radius but not the microlens parallax, and thus we perform a Bayesian analysis to estimate the physical parameters of the lens. We find that the OGLE-2019-BLG-0362L system is a super-Jovian-mass planet $M_p=3.26^{+0.83}_{-0.58}M_J $ orbiting an M dwarf $M_h=0.42^{+0.34}_{-0.23}M_{\odot}$ at a distance $D_L=5.83^{+1.04}_{-1.55}kpc$. The projected star-planet separation is ${\alpha}_{\bot}= 2.18^{+0.58}_{-0.72}AU$, which indicates that the planet lies beyond the snow line of the host star.

The Early Chemical Enrichment Histories of Two Sculptor Group Dwarf Galaxies as Revealed by RR Lyrae Variables

  • Yang, Soung-Chul;Wagner-Kaiser, Rachel;Sarajedini, Ata;Kim, Sang Chul;Kyeong, Jaemann
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.1
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    • pp.39.1-39.1
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    • 2014
  • We present the results of our analysis of the RR Lyrae (RRL) variable stars detected in two transition-type dwarf galaxies (dTrans), ESO294-G010 and ESO410-G005 in the Sculptor group, which is known to be one of the closest neighboring galaxy groups to our Local Group. Using deep archival images from the Advanced Camera for Surveys (ACS) onboard the Hubble Space Telescope (HST), we have identified a sample of RR Lyrae candidates in both dTrans galaxies [219 RRab (RR0) and 13 RRc (RR1) variables in ESO294-G010; 225 RRab and 44 RRc stars in ESO410-G005]. The metallicities of the individual RRab stars are calculated via the period-amplitude-[Fe/H] relation derived by Alcock et al. This yields mean metallicities of <[Fe/H]>_{ESO294} = -1.77 +/- 0.03 and <[Fe/H]>_{ESO410} = -1.64+/- 0.03. The RRL metallicity distribution functions (MDFs) are investigated further via simple chemical evolution models; these reveal the relics of the early chemical enrichment processes for these two dTrans galaxies. In the case of both galaxies, the shapes of the RRL MDFs are well-described by pre-enrichment models. This suggests two possible channels for the early chemical evolution for these Sculptor group dTrans galaxies: 1) The ancient stellar populations of our target dwarf galaxies might have formed from the star forming gas which was already enriched through "prompt initial enrichment" or an "initial nucleosynthetic spike" from the very first massive stars, or 2) this pre-enrichment state might have been achieved by the end products from more evolved systems of their nearest neighbor, NGC 55.

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How Supernovae Ejecta Is Transported In A Galaxy: DependenceOn Hydrodynamic Schemes In Numerical Simulations

  • Shin, Eun-jin;Kim, Ji-hoon
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.2
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    • pp.48.4-48.4
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    • 2019
  • We studied the metal-distribution of isolated Milky-way mass galaxy using various hydrodynamic solvers and investigated the difference of the result between AMR and SPH codes. In particle-based codes, physical quantities like mass or metallicity defined in each particle are conserved unless being injected explicitly by the effect of the supernova, whereas in the Eulerian codes the diffusion is simply accomplished by hydro-equation. Therefore, without including explicit physics of diffusion on the SPH- codes, the metal mixing in the galaxy or CGM only can be accomplished by the direct motion of the particles, however, the standard-SPH codes depress the instability of the turbulent fluid mixing. In this work, we simulated under common initial conditions, common gas-physics like cooling-heating models, and star-formation feedback using ENZO(AMR) GIZMO and GADGET-2 codes. We additionally included a metal-diffusion algorithm on the SPH-codes, which follows the subgrid-turbulent mixing model investigated by Shen et al. (2010) and compared the effect of the metal-outflow on the halo region of the galaxy in different hydro-solvers. We also found that for the implementation of the diffusion scheme in the SPH-codes, the existence of a sufficient number of the gas-particles, which is the carrier of the metals, is necessary. So we tested a new initial condition for proper implementation of the diffusion scheme on the SPH simulations. By comparing the metal-contamination of the circumgalactic medium with different hydrodynamics models, we quantify the diffusion strength of AMR codes using diffusion parameterization of the SPH codes and also suggest the calibration solutions in the different behavior of codes in metal-outflow.

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High redshift galaxy clusters and superclusters in ELAIS-N1

  • Hyun, Minhee;Im, Myungshin;Kim, Jae-Woo;Lee, Seong-Kook;Edge, Alastair C.
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.1
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    • pp.79.3-80
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    • 2015
  • Galaxy overdensities such as galaxy clusters and superclusters are the largest gravitationally bound systems in the Universe. Since they contain many different levels of local densities, they are excellent places to test galaxy evolution models in connection to the environments. The environment studies of galaxies at z ~ 1 are important because the environmental quenching seems to be an important mechanism to reduce star formation activities in galaxies at z < 1. However, there have been not many studies about high redshift galaxy clusters at z ~ 1 because of the lack of wide and deep multi-wavelength data. We have used the multi-wavelength data from the UKIDSS DXS (J and K band), the SWIRE (4 IRAC bands), and the PAN-STARRS (g, r, i, z, y bands) in the ELAIS-N1 field. We identified galaxy cluster candidates at 0.2 < z < 1.6 using the multi-wavelength data. We found several superclusters where cluster candidates are concentrated on few tens of Mpc scale. Interestingly, some of the supercluster candidates consist of galaxy clusters which have high blue galaxy. We will present high redshift galaxy cluster and supercluster candidates in ELAIS-N1 field and galaxy properties in different environments including dense clusters and fields.

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Numerical Study of Current and Wind Forces Acting on Two Floating Bodies in Tandem Configuration (직렬 배치된 두 부유체에 작용하는 조류력 및 풍력 특성에 관한 수치해석 연구)

  • Hong, Jang-Pyo;Nam, Bo Woo;Yoon, Kyoung-Won;Kim, Young-Sik;Sung, Hong-Gun
    • Journal of Ocean Engineering and Technology
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    • v.28 no.5
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    • pp.378-386
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    • 2014
  • In this study, the characteristics of the current and wind forces acting on two floating bodies were numerically investigated using a commercial CFD software, STAR-CCM+. In the numerical analyses, LNGC was located right behind FSRU under uniform current or wind conditions. Steady calculations were carried out using a Reynolds averaged Navier-Stokes (RANS) solver and the realized k-epsilon model. First, the current coefficients of FSRU based only the CFD were compared with the model test data. Through this comparison, the present numerical models and mesh systems were indirectly verified. Next, computations for FSRU and LNGC in a uniform current were performed using different relative positions. It was found that the current coefficients were great affected by the longitudinal positions. Finally, the wind forces acting on FSRU and LNGC in tandem configurations were studied. The focus was on the shielding effects due to the aerodynamic interactions between FSRU and LNGC.