• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.4 no.2
• /
• pp.55-64
• /
• 1984

Presented is a nonlinear constitutive model for progressive tensile fracturing of concrete. The model is incremental, path-dependent, and tensorialy invariant. The total strain tensor is assumed to be a sum of a purely elastic component and an inelastic component. The material is considered to contain weak planes of all directions which characterize the planes of the microcracks. A one-to-one functional dependence is assumed between the normal stress and the normal strain across each of the weak planes. The tangential stiffness of concrete is then derived form the principle of virtual work. The present theory can be applied to loading histories which are nonproportional or during which the principal directions rotate. Good agreement with the available direct tensile test data which cover strain-softening is demonstrated.

• The Bulletin of The Korean Astronomical Society
• /
• v.36 no.2
• /
• pp.66.2-66.2
• /
• 2011

The unexpected rising flux of early-type galaxies at decreasing ultraviolet (UV) wavelengths is a long-standing mystery. One important observational constraint is the correlation between UV-optical colours and Mg2 line strengths found by Burstein et al. (1988). The simplest interpretation of this phenomenon is that the UV strength is related to the Mg line-strength. Under this assumption, we expect galaxies with larger Mg gradients to have larger UV colour gradients. By combining UV imaging from GALEX, optical imaging from MDM and SAURON integral-field spectroscopy, we investigate the spatially-resolved relationships between UV colours and stellar population properties of 34 early-type galaxies from the SAURON survey sample. We find that galaxies with old stellar populations show tight correlations between the FUV colours (FUV-V and FUV-NUV) and the Mg b index, $H{\beta}$ index and metallicity [Z/H]. We have also derived logarithmic internal radial colour, measured line strength and derived stellar population gradients for each galaxy and again found a strong dependence of the FUV-V and FUV-NUV colour gradients on both the Mg b line-strength and the metallicity gradients. In particular, global gradients of Mg b and [Z/H] with respect to the UV colour across galaxies are consistent with their local gradients within galaxies, suggesting that the global correlations also hold locally. From a simple model based on multi-band colour fits of UV upturn and UV-weak galaxies, we have identified a plausible range of parameters that reproduces the observed radial colour profiles. In these models, the centers of elliptical galaxies, where the UV flux is strong, are enhanced in metals by roughly 60% compared to UV-weak regions.

• KDI Journal of Economic Policy
• /
• v.30 no.2
• /
• pp.27-59
• /
• 2008

This paper empirically investigates the finance-growth linkage in Korea by utilizing firm-level data of manufacturing industries before and after the 1997 financial crisis. We find that, first, an increase in external finance is associated with a faster subsequent capital accumulation of firms. However, this capital accumulation channel became relatively attenuated after the crisis. Second, the total factor productivity growth effect of external finance has been considerably weak both before and after the crisis. Third, the information production and industry restructuring effects of external finance have also remained weak after the crisis. The limited role of external finance in post-crisis Korea partially reflects sluggish corporate investment and weakening dependence of good credit firms on external finance. The evidence suggests that, in order to effectively sustain economic growth, further reform efforts may be required to strengthen resource allocation and corporate restructuring roles of financial markets and institutions.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.125.1-125.1
• /
• 2012

The wave number 4 (wave-4) and wave number 3 (wave-3) longitudinal structures in the thermospheric neutral mass density are understood as tidal structures driven by diurnal eastward-propagating zonal wave number 3 (DE3) and wave number 2 (DE2) tides, respectively. However, those structures have been identified using data from limited time periods, and the consistency and recurrence of those structures have not yet been examined using long-term observation data. We examine the persistence of those structures by analyzing the neutral mass density data for the years 2001-2008 taken by the CHAllenging Minisatellite Payload (CHAMP) satellite. During years of low solar activity, the amplitude of the wave-4 structure is pronounced during August and September, and the wave-4 phase shows a consistent eastward phase progression of $90^{\circ}$ within 24 h local time in different months and years. During years of high solar activity, the wave-4 amplitude is small and does not show a distinctive annual pattern, but the tendency of the eastward phase shift at a rate of $90^{\circ}$/24 h exists. Thus the DE3 signature in the wave-4 structure is considered as a persistent feature. The wave-3 structure is a weak feature in most months and years. The amplitude and phase of the wave-3 structure do not show a notable solar cycle dependence. Among the contributing tidal modes to the wave-3 structure, the DE2 amplitude is most pronounced. This result may suggest that the DE2 signature, although it is a weak signature, is a perceivable persistent feature in the thermosphere.

• Monthly Notices of the Royal Astronomical Society
• /
• v.491 no.3
• /
• pp.4057-4068
• /
• 2020

Elliptical galaxies today appear aligned with the large-scale structure of the Universe, but it is still an open question when they acquire this alignment. Observational data are currently insufficient to provide constraints on the time evolution of intrinsic alignments, and hence existing models range from assuming that galaxies gain some primordial alignment at formation, to suggesting that they react instantaneously to tidal interactions with the large-scale structure. Using the cosmological hydrodynamical simulation Horizon-AGN, we measure the relative alignments between the major axes of galaxies and eigenvectors of the tidal field as a function of redshift. We focus on constraining the time evolution of the alignment of the main progenitors of massive z = 0 elliptical galaxies, the main weak-lensing contaminant at low redshift. We show that this population, which at z = 0 has a stellar mass above 10^10.4 M_⊙, transitions from having no alignment with the tidal field at z = 3, to a significant alignment by z = 1. From z = 0.5, they preserve their alignment at an approximately constant level until z = 0. We find a mass dependence of the alignment signal of elliptical progenitors, whereby ellipticals that are less massive today (10^10.4 < M/M_⊙ < 10^10.7) do not become aligned till later redshifts (z < 2), compared to more massive counterparts. We also present an extended study of progenitor alignments in the parameter space of stellar mass and galaxy dynamics, the impact of shape definition, and tidal field smoothing.

• Industry Promotion Research
• /
• v.6 no.4
• /
• pp.39-45
• /
• 2021

This study presented the role of the counselor's transitional object through literature research, focusing on Winnicott's theory. In the process of development, infants experience anxiety when they move from absolute dependence to relative dependence with their mother. In this way, the counselor's role as an transitional object buffers separation anxiety and depressive anxiety about the loss experience, and mediates from the omnipotent fantasy to the real world. transitional objects are new objects and have a function of contributing to adaptation in reality. And it leads to the stage of separation and individualization through transitional object and transitional phenomena. It can be said that he acquires a sense of the real other that exists in order to create and destroy omnipotent, and to adapt to reality. A good enough mother makes the child's omnipotence meaningful. In this case, the true self helps the infant's weak self to grow and lead him to live his own life. When the mother fails to satisfy the infant's needs, her fantasies and spontaneous impulses are lacking. In other words, when the mother fails to reflect the infant's needs, the infant looks at her mother's mood, giving up her true self and creating a false self. The pathology of the absolute dependence phase is caused by the failure of a good enough mother's empathy and nurturing environment. At this time, the child experiences the collapse of the omnipotence illusion and experiences annihilation anxiety. Therefore, effective counseling can be carried out when providing a comfortable and stable environment by reducing separation anxiety and depressive anxiety of clients through the role of the counselor's transitional object in the counseling field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.205-205
• /
• 2009

As a p-type semiconductor NiO is potential material which can be used in many application including QD-LED. NiO films were deposited on glass substrates using rf-sputtering method. The properties of resistivity, surface roughness, etc in the NiO films were investigated at different sputtering parameters. The resistivity of $l.88{\times}10^{-2}{\sim}3.71{\times}10^{-2}{\Omega}cm$ with sputtering power(80~200 watts) and change was very low. The sputtering pressure at 3~60 mTorr resulted in rather broad change ofresistivity of $0.58{\times}10^{-2}{\sim}4.67{\Omega}cm$. The oxygen content in sputtering gas was found to be very effective to control the resistivity from $2.01{\times}10^{-2}$ to $1.22{\times}10^2{\Omega}cm$ with 100~2.5% $O_2$ in Ar gas. In addition, the surface roughness showed the RMS values of 0.6~1.1 nm and the dependence on sputtering parameters was weak.

• Journal of The Korean Astronomical Society
• /
• v.51 no.4
• /
• pp.73-88
• /
• 2018

We present a sample of 54 disk galaxies which have well developed extraplanar structures. We selected them using visual inspections from the color images of the Sloan Digital Sky Survey. Since the sizes of the extraplanar structures are comparable to the disks, they are considered as prominent stellar halos rather than large bulges. A single $S{\acute{e}}rsic$ profile fitted to the surface brightness along the minor-axis of the disk shows a luminosity excess in the central regions for the majority of sample galaxies. This central excess is considered to be caused by the central bulge component. The mean $S{\acute{e}}rsic$ index of the single component model is $1.1{\pm}0.9$. A double $S{\acute{e}}rsic$ profile model that employs n = 1 for the inner region, and varying n for the outer region, provides a better fit than the single $S{\acute{e}}rsic$ profile model. For a small fraction of galaxies, a $S{\acute{e}}rsic$ profile fitted with n = 4 for the inner region gives similar results. There is a weak tendency of increasing n with increasing luminosity and central velocity dispersion, but there is no dependence on the local background density.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.37 no.1
• /
• pp.69-75
• /
• 2000

In this paper, we consider the problem of discrete-time random signal detection problem under the presence of additive noise exhibiting weak dependence The test statistic of the locally optimum detector for correlated random signals under a weakly dependent noise model is derived The performance characteristic of the locally optimum detector is analyzed and compared with that of the square-law detector in terms of the asymptotic relative efficiency.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.37 no.1
• /
• pp.76-82
• /
• 2000

In this paper, we consider nonparametric signal detection problems under the presence of additive noise exhibiting weak dependence We derive the test statistics of the locally optimum rank detectors under a weakly dependent noise model for known and random signal cases The performance characteristic of the locally optimum rank detectors are analyzed in terms of asymptotic relative efficiency.