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        검색결과 33

        21.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cosmology considers the Hubble redshift of galaxy light by the Doppler effect as proof the Universe has been expanding since the Big Bang. However, cosmic dust that permeates the Universe also redshifts galaxy light that if not corrected over-predicts the velocities of all astronomical measurements inferred by the Doppler effect. Hubble redshifts corrected for cosmic dust suggest the Universe may not be expanding, the consequence of which may allow the outstanding problems in cosmology to possibly be resolved by Newtonian mechanics.
        3,000원
        22.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Determining the absolute neutrino mass scale and the neutrino mass hierarchy are central goals in particle physics, with important implications for the Standard Model. However, the final answer may come from cosmology, as laboratory experiments provide measurements for two of the squared mass dif- ferences and a stringent lower bound on the total neutrino mass - but the upper bound is still poorly constrained, even when considering forecasted results from future probes. Cosmological tracers are very sensitive to neutrino properties and their total mass, because massive neutrinos produce a specific redshift- and scale-dependent signature in the power spectrum of the matter and galaxy distributions. Stringent upper limits on P m will be essential for understanding the neutrino sector, and will nicely complement particle physics results. To this end, we describe here a series of cosmological hydrodynamical simulations which include massive neutrinos, specifically designed to meet the requirements of the Baryon Acous- tic Spectroscopic Survey (BOSS) and focused on the Lyman-α (Lyα) forest - also a useful theoretical ground for upcoming surveys such as SDSS-IV/eBOSS and DESI. We then brie y highlight the remark- able constraining power of the Lyα forest in terms of the total neutrino mass, when combined with other state-of-the-art cosmological probes, leading to a stringent upper bound on ∑mv.
        4,000원
        23.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        If the present universe is slightly open then pre-in ation curvature would appear as a cosmic dark-flow component of the CMB dipole moment. We summarize current cosmological constraints on this cosmic dark ow and analyze the possible constraints on parameters characterizing the pre-in ating universe in an in ation model with a present-day very slightly open ΛCDM cosmology. We employ an analytic model to show that for a broad class of in ation-generating effective potentials, the simple requirement that the observed dipole moment represents the pre-in ation curvature as it enters the horizon allows one to set upper and lower limits on the magnitude and wavelength scale of pre-in ation uctuations in the in aton field and the curvature parameter of the pre-in ation universe, as a function of the fraction of the total initial energy density in the in aton field. We estimate that if the current CMB dipole is a universal dark flow (or if it is near the upper limit set by the Planck Collaboration) then the present constraints on ΛCDM cosmological parameters imply rather small curvature Ωk ~ 0:1 for the pre-in ating universe for a broad range of the fraction of the total energy in the in aton field at the onset of in ation. Such small pre-in ation curvature might be indicative of open-in ation models in which there are two epochs of in ation.
        4,000원
        25.
        2012.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Physical cosmology tries to understand the Universe at large with its origin and evolution. Observational and experimental situations in cosmology do not allow us to proceed purely based on the empirical means. We examine in which sense our cosmological assumptions in fact have shaped our current cosmological worldview with consequent inevitable limits. Cosmology, as other branches of science and knowledge, is a construct of human imagination reflecting the popular belief system of the era. The question at issue deserves further philosophic discussions. In Whitehead’s words, “philosophy, in one of its functions, is the critic of cosmologies.” (Whitehead 1925).
        4,000원
        26.
        2012.04 구독 인증기관·개인회원 무료
        29.
        2008.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is generally known that the temple structure in Korea was formalized by the ceremonial principle based on the Buddhist cosmology. But, there have been no concrete studies on how far the two have relationship with each other and what significance it implies in it. In other words, even though the temple structure reflects the Sumeru Mount cosmology which is the Buddhist cosmology, there is still uncertain aspects in the relationship between them. This research is a more concrete approach on what kind of corelation the Sumeru Mount cosmology has with the Korean temple structure. For this, the levels of related documents on the Buddhist cosmology and the Sumeru Mount cosmology have been arranged first. Then, on this basis, it is searched with what symbolism the cosmology has been accepted in the temple structure. The temple is a sacred space that holds Buddha and a profane space which the sattva (ordinary people) can approach at the same time. The site of the temple is also a land that is connected to the residence of sattva and a blissful area of prayer that they can be born again through Buddha at the same time. Thus, the double characteristics of sanctity and profanity are finally inter-connected with each other in the view point of Jinsokburi(Truth and Worldliness are not different), and the temple structure reflects this significance through the symbolism very well. Therefore, the correct recognition on the temple structure can be said as an important aspect to understand the purpose of Buddhism.
        5,500원
        30.
        2005.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        To constrain the values of the model parameters for the cosmological models involving the time-decaying Λ term, we have computed sets of theoretical predictions for the N-m relation of galaxies as well as the CMB angular power spectrum: three types of variation, viz., Λ ∝ T-1, a-m, and Hn are thereby assumed following Overduin & Cooperstock (1998), although we concentrate here on the discussion of the results obtained from the first type. Our results for the N-m relation indicate that the observed excess of the galaxy counts N in the faint region beyond the blue apparent magnitude 24 can be reasonably well accounted for with the value of Ɩ in the range between 0.2 and 1. Furthermore, a comparison of our computational results of the CMB spectra with the observational data shows that the models with a mild degree of the Λ term decay, viz., with the value of Ɩ ≾ 0.4, are favorable. In this case, the age of our universe turns out to be larger than or equal to 14 Gyr, the lower limit inferred from some Uranium datings.
        3,000원
        31.
        1996.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Super-inflation driven by dilaton/moduli kinetic energy is naturally realized in compactified string theory. Discussed are selected topics of recent development in string inflationary cosmology: kinematics of super-inflation, graceful exit triggered by quantum back-reaction, and classical and quantum power spectra of density and metric perturbations.
        3,000원
        32.
        1996.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Recent discussions of observational constraints on the standard hot big bang model are reviewed and it is argued that now there is room for considering alternative cosmologies. The quasi-steady state cosmology is briefly described. This model seems to explain most of the observed features of the universe, including the m-z relation, radio source count, the light nuclear abundances and the microwave background.
        4,000원
        33.
        1992.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We may consider the following three fundamental epistemological questions concerning cosmology. Can cosmology at last understand the origin of the universe? Can computers at last create? Can life be formed at last synthetically? These questions are in some sense related to the liar paradox containing the self-reference and, therefore. may not be answered by recursive processes in finite time. There are, however. various implications such that the chaos may break the trap of the self-reference paradox. In other words, Goedel's incompleteness theorem would not apply to chaos, even if the chaos can be generated by recursive processes. Internal relations among cosmology, epistemology and chaos must be investigated in greater detail.
        4,000원
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