• Title/Summary/Keyword: evolutionary status

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CALIBRATION OF STELLAR PARAMETERS OF 85 PEG SYSTEM

  • Bach, Kiehunn;Kim, Yong-Cheol;Demarque, Pierre
    • Journal of Astronomy and Space Sciences
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    • v.24 no.1
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    • pp.31-38
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    • 2007
  • We have investigated the evolutionary status of 85 Peg within the framework of standard evolutionary theory. 85 Peg has been known to be a visual and spectroscopic binary system in the solar neighborhood. In spite of the accurate information of the total mass (${\sim}1.5M_{\odot}$) and the distance (${\sim}12pc$) from the HIPPARCOS parallax, it has been undetermined an individual mass, therefore the evolved status of the system. Moreover, the coupled uncertainties of chemical composition and age, make matters worse in predicting an evolutionary status of the system. Nevertheless, we computed the various possible models for 85 Peg, and then calibrated stellar parameters by adjusting to the recent observational data. Our modelling computation has included recently updated input physics and stellar theory such as opacity, equation of state, and chemical diffusion. Through a statistical assessment, we have derived a confident parameter set as the best solution which minimized $X^{2}$ within the observational error domain. Most of all, we found that 85 Peg is not a binary system but a triple system with an unseen companion 85 Peg $B_{b}\;{\sim}0.16M_{\odot}$. The aim of the present paper is (1) to provide a complete modelling of the stellar system based on the evolutionary theory, and (2) to constrain the physical dimensions such as mass, metallicity and age.

Evolutionary status of four detached binary stars

  • Kanjanasakul, Chanisa
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.49.2-49.2
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    • 2010
  • We have presented the evolutionary status of four detached double line spectroscopic eclipsing binaries which are CD Tau, CM Lac, HS Hya and ZZ Boo because the component stars of these binary systems still act as a single star. We determined the absolute dimensions of these binary systems using photometric and spectroscopic solutions from analysis of light curves and radial velocity curves. Using the luminosities, effective temperatures and masses we choose evolutionary tracks of these binary systems. Finally we obtained ages and metallicity of the stars. We found that CM Lac and HS Hya are very young stars and their ages are in range of 0.15-1.05 and 0.22-1.14 Gyrs. For CD Tau and ZZ Boo, they are older than the others and their age in range of 1.95-2.95 and 1.48-1.73 Gyrs.

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Evolutionary status of seven detached binary stars

  • Kanjanasakul, Chanisa;Kang, Young-Woon
    • Bulletin of the Korean Space Science Society
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    • 2010.04a
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    • pp.32.4-32.4
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    • 2010
  • Evolution of the Cosmos (ARCSEC). We have presented the evolutionary status of seven detached double line spectroscopic eclipsing binaries which are CD Tau, CM Lac, CW CMa, HS Hya, IT Cas, KM Hya, and ZZ Boo because the component stars in the binary systems still act as a single star. We determined the absolute dimensions of the binary systems using photometric and spectroscopic solutions by analyzing of the light curves and radial velocity curves. We chose evolutionary tracks of these binary systems. Using the luminosities, effective temperatures and masses. Finally we obtained ages and metallicity of the stars.

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EVOLUTIONARY STATUS AND INTERNAL STRUCTURE OF μ CASSIOPEIAE

  • BACH, KIEHUNN
    • Journal of The Korean Astronomical Society
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    • v.48 no.3
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    • pp.165-175
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    • 2015
  • We investigate physical properties of the nearby (∼ 7.5 pc) astrometric binary μ Cas in the context of standard evolutionary theory. Based on the spectroscopically determined relative abundances ([α/Fe] ≳ +0.4 dex, [Fe/H] ∼ −0.7 dex), all physical inputs such as opacities and equation of state are consistently generated. By combining recent spectroscopic analyses with the astrometric observations from the HIPPARCOS parallaxes and the CHARA array, the evolutionary model grids have been constructed. Through the statistical evaluation of the χ2-minimization among alternative models, we find a reliable evolutionary solution (MA, MB, tage) = (0.74 M, 0.19 M, 11 Gyr) which excellently satisfies observational constraints. In particular, we find that the helium abundance of μ Cas is comparable with the primordial helium contents (Yp ∼ 0.245). On the basis of the well-defined stellar parameters of the primary star, the internal structure and the p-mode frequencies have been estimated. From our seismic computation, μ Cas is expected to have a first order spacing ∆ν ∼ 169 μHz. The ultimate goal of this study is to describe physical processes inside a low-mass star through a complete modelling from the spectroscopic observation to the evolutionary computation.

PROPERTIES OF OH/IR STARS WITH THE IRAS LRS SPECTRA

  • CHEN P. S.;KWOK S.
    • Journal of The Korean Astronomical Society
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    • v.29 no.spc1
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    • pp.257-258
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    • 1996
  • 1607 OH/IR stars associated with IRAS sources are assembled and the IRAS LRS spectra of 980 OH/IR stars are examined in this paper. The nature of the circumstellar dust for these sources is classified. The distributions of these subgroups of OH/IR stars in the IRAS color-color diagram and the period-color diagram are interpreted with their evolutionary status. The Galactic and the velocity distributions of these subgroups of OH/IR stars are also presented. The correlations among the expanding velocities of the envelopes, colors, periods and the pumping efficiencies for subgroups of OH/IR stars are investigated to outline the evolutionary status of OH/IR stars.

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A Study for searching optimized combination of Spent light water reactor fuel to reuse as heavy water reactor fuel by using evolutionary algorithm (진화 알고리즘을 이용한 경수로 폐연료의 중수로 재사용을 위한 최적 조합 탐색에 관한 연구)

  • 안종일;정경숙;정태충
    • Journal of Intelligence and Information Systems
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    • v.3 no.2
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    • pp.1-9
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    • 1997
  • These papers propose an evolutionary algorithm for re-using output of waste fuel of light water reactor system in nuclear power plants. Evolutionary algorithm is useful for optimization of the large space problem. The wastes contain several re-useable elements, and they should be carefully selected and blended to satisfy requirements as input material to the heavy water nuclear reactor system. This problem belongs to a NP-hard like the 0/1 Knapsack problem. Two evolutionary strategies are used as a, pp.oximation algorithms in the highly constrained combinatorial optimization problem. One is the traditional strategy, using random operator with evaluation function, and the other is heuristic based search that uses the vector operator reducing between goal and current status. We also show the method, which performs the feasible teat and solution evaluation by using the vectorized data in problem. Finally, We compare the simulation results of using random operator and vector operator for such combinatorial optimization problems.

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Evolutionary Approaches to Low Fertility in Modern Societies (현대 사회의 저출산에 대한 진화적 분석)

  • Joonghwan Jeon
    • Korean Journal of Culture and Social Issue
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    • v.18 no.1
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    • pp.97-110
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    • 2012
  • The sharp decline of fertility in industrialized countries since the 19th century constitutes a major problem for evolutionary approaches to human behavior. Why would people voluntarily reduce their total number of offspring, despite the fact that resources are so abundant in modern times? Here I review three evolutionary hypotheses for low fertility in modern societies, and discuss how the evolutionary perspective could shed new light on solving the problem of low fertility in Korea. Low fertility may be 1) a maladaptive outcome from the mismatch between our ancestral environments and evolutionarily novel environments, 2) a consequence of gene-culture coevolution where traits that reduce genetic fitness can still spread through a population as a result of imitation, especially if the traits are expressed by high-status people, or 3) an adaptation that maximize parents' long-term genetic fitness in knowledge-based industrialized societies where high parental investment is required for rearing competitive offspring. Based on these considerations, I suggest how the evolutionary explanations of low fertility can be applied to increasing the birth rate in Korea.

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Health Literacy: An Evolutionary Concept Analysis (건강정보 이해능력(Health Literacy)에 대한 개념분석)

  • Kim, Sungeun;Oh, Jina;Lee, Yunmi
    • The Journal of Korean Academic Society of Nursing Education
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    • v.19 no.4
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    • pp.558-570
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    • 2013
  • Purpose: In these days, the concept of health literacy becomes important because it is essential to have a clear grasp of patients' basic ability to understand health-care information. Therefore, we intended to discover attributes, antecedents and consequences of health literacy through contextual analysis. Method: Following Rodgers' evolutionary concept analysis, we did a literary review. The databases KMBase, KoreaMed, Kstudy, NDSL, and RISS were searched for articles. Among published literature about health literacy, twenty articles which satisfied the inclusion criteria were chosen. Results: Health literacy consists of three attributes: information seeking, information understanding, and information utilizing. Furthermore antecedents are as follows: health status, health belief, socioeconomic status, and information quality. Finally, we were able to explain the consequences of health literacy by showing improvement of self-care and interaction, and a decrease of social costs. Conclusion: We expect this study to guide the direction of future studies, and as a concept analysis that examines the conceptual attributes in the context of health literacy. Based on the result of this study, the design of a standardized tool and the program of health literacy promotion education need to be developed.

A Concept Analysis of Gratitude in Patients Based on Rodgers' Evolutionary Method

  • Jung, Miran;Han, Kuemsun
    • International Journal of Contents
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    • v.13 no.2
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    • pp.44-49
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    • 2017
  • This article presents a concept analysis of the gratitude experience of diseased patients. The Rodgers' Evolutionary Method was used for conducting the analysis. A search of CINAHL, MEDLINE, PsycARTICLES, and Springer databases was conducted using "gratitude or appreciation or thanks" and "patient or illness" as a key word, 22 final articles were selected. Three critical attributes of gratitude in patients were identified: positive emotions, acceptance of the current status, and a driving force to plant the will of life. In addition, two antecedents of gratitude in patients were identified: interactions with people or the environment, and the perception of a favorable stimuli or help. Two consequences of gratitude in patients were identified: an increased compliance in implemented treatment, and an enhancement of trust relationship. The concept analysis describes diseased patients' gratitude. This paper will become the basis for future clinical research related to diseased patients' gratitude.

Internet-Based Remote Control of the Intelligent Robot (지능형 로봇의 인터넷 기반 원격 제어)

  • Yu, Young-Sun;Kim, Jong-Sun;Kim, Hyong-Suk;Joo, Young-Hoon
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.3
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    • pp.242-248
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    • 2007
  • In this paper, we implement the internet-based remote control system for intelligent robot. For remote control of the robot, it uses the socket communication of the TCP/IP. It consists of the user interface and the robot control interface. Robot control interface transmits the navigation and environmental informations of the robot into the user interface. In order to transmit the large environmental images, a JPEG compression algorithm is used. User interface displays the navigation status of the robot and transmits the navigation order into the robot control interface. Also, we propose the design method of the fuzzy controller using navigation data acquired by expert's knowledge or experience. To do this, we use virus-evolutionary genetic algorithm(VEGA). Finally, we have shown the proposed system can be operated through the real world experimentations.