• 제목/요약/키워드: evolutionary status

검색결과 70건 처리시간 0.01초

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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    • 제24권1호
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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
    • 천문학회보
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    • 제35권1호
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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
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
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    • 한국우주과학회 2010년도 한국우주과학회보 제19권1호
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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
    • 천문학회지
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    • 제48권3호
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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.
    • 천문학회지
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    • 제29권spc1호
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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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진화 알고리즘을 이용한 경수로 폐연료의 중수로 재사용을 위한 최적 조합 탐색에 관한 연구 (A Study for searching optimized combination of Spent light water reactor fuel to reuse as heavy water reactor fuel by using evolutionary algorithm)

  • 안종일;정경숙;정태충
    • 지능정보연구
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    • 제3권2호
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    • pp.1-9
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    • 1997
  • 본 논푼에서는 경수로 원자력 발전소의 사용 후 핵연료를 중수로의 핵연료로 재사용하기 위해 사용 후 경수로 핵연료의 최적 조합을 찾는데 진화 알고리즘(Evolutionary Algorithm)을 이용하여 해결해 보고자 한다. 진화 알고리즘은 대규모 문제 공간에서 최적화 문제를 해결하는데 적합한 알고리즘이다. 사용 후 경수로 핵연료에는 중수로에서 사용할 수 있는 유용한 원자들을 많이 포함하고 있지만 핵연료 봉마다 그 함량이 다양하고, 중수로 연료가 되기 위한 제약 조건 때문에 최적 조합 전략이 펼요하다. 사용후 핵연료의 조합 문제는 알고리즘 분야에서 대표적인 조합 최적화 문제인 0/1 Knapsack문제와 같이 Non-Polynomial (NP) Complete문제에 해당한다. 이러한 문제를 해결하기 위해셔는 고전적언 전화 알고리즘의 전략에 기반하여 랜덤 연산자를 이용하되 평가 함수 값이 좋은 방향으로만 탐색을 수행하는 방법이 있으나 이것은 탐색의 효율면에셔 좋지 않다. 따라서 본 연구에서는 벡터 연산자를 이용하여 최적의 해를 보다 빨리 얻을 수 있는 휴리스틱을 사용하는 방법을 제안한다. 본 논문에서는 경수로 핵연료 조합 문제 영역의 모든 지식을 벡터화하여 벡터의 연산만으로 가능성 검사, 해를 평가 하는 방법을 소개한다. 또한 벡터 휴리스틱이 고전적인 진화 알고리즘에 비해 어느 정도의 성능을 보이는지 비교한다.

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

  • 전중환
    • 한국심리학회지 : 문화 및 사회문제
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    • 제18권1호
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    • pp.97-110
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    • 2012
  • 19세기부터 현재까지 산업화된 국가들을 중심으로 출산율이 급락하고 있는 전세계적인 현상은 진화적인 관점에서 선뜻 이해하기 어렵다. 왜 자원이 더 풍부해진 현대에 들어서 사람들은 자식수를 자발적으로 줄이는가? 본 논문은 현대의 저출산 현상을 설명하는 다양한 진화적 접근들을 요약하고, 이를 토대로 우리 사회의 저출산 문제를 해결할 실마리를 얻고자 한다. 1) 현대의 극히 낮은 출산율은 수렵-채집 생활에 맞추어진 우리의 심리적 적응이 진화적으로 낯선 환경과 불협화음을 일으킴에 따른 부적응적인 부산물이라는 가설, 2) 사회적으로 성공한 사람들이 자녀를 적게 낳는 행동이 전파되거나, 가족 중심의 네트워크가 붕괴하여 출산의 중요성이 덜 강조됨에 따라 저출산이 야기되었다는 유전자-문화 공진화 가설, 그리고 3) 부모가 자녀에게 투자하는 양이 대단히 많이 요구되는 현대의 환경에서 극심한 저출산은 부모의 장기적인 적합도를 최대화하는 적응적인 형질이라는 가설을 차례대로 검토한다. 저출산에 대한 진화적 관점은 저소득층의 출산을 지원하는 정책보다는 모든 사회경제적 계층에서 자녀를 장차 경쟁력 있는 성인으로 키우기 위한 비용을 줄이는 정책을 추진하는 것이 더 효과적임을 시사한다.

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

  • 김성은;오진아;이윤미
    • 한국간호교육학회지
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    • 제19권4호
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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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    • 제13권2호
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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.

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

  • 유영선;김종선;김형석;주영훈
    • 제어로봇시스템학회논문지
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    • 제13권3호
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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.