• Communications of the Korean Mathematical Society
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• v.33 no.3
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• pp.1025-1037
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• 2018

We consider an ill-posed problem for the heat equation $u_{xx}=u_t$ in the quarter plane {x > 0, t > 0}. We propose a new method to compute the heat flux $h(t)=u_x(1,t)$ from the boundary temperature g(t) = u(1, t). The operator $g{\mapsto}h=Hg$ is unbounded in $L^2({\mathbb{R}})$, so we approximate h(t) by $h_{\delta}(t)=u_x(1+{\delta},\;t)$, ${\delta}{\rightarrow}0$. When noise is present, the data is $g_{\epsilon}$ leading to a corresponding heat $h_{{\delta},{\epsilon}}$. We obtain an estimate of the error ${\parallel}h-h_{{\delta},{\epsilon}}{\parallel}$, as well as the error when $h_{{\delta},{\epsilon}}$ is approximated by the trapezoidal rule. With an a priori choice rule ${\delta}={\delta}({\epsilon})$ and ${\tau}={\tau}({\epsilon})$, the step size of the trapezoidal rule, the main theorem gives the error of the heat flux as a function of noise level ${\epsilon}$. Numerical examples show that the proposed method is effective and stable.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.89-95
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• 2005

In this paper, a quad-band antenna for GSM/GPS/DCS/US-PCS handsets is proposed. The proposed antenna is low-profile for mounting in limited inner space of a handset. It consists of three open points with quarter wave length for multi-band operation. The ground plane below the patch is removed for wide-bandwidth without the variation of antenna size and the slot is added at the center of the patch for convenient matching in high frequency band. It provides a enough bandwidth within VSWR 3:1 at all bands. In addition, the measured peak gains are between -2.19 and 2.09 in anechoic chamber (10m$\times$6m$\times$4m).

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.861-864
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• 1999

We designed and fabricated microstrip line fed QMSAs(Quarter-Wavelength Microstrip Antenna) for 850〔MHz〕 band on the CGP-500 Copper-clad Laminates substrate (CHUKOH company) with $\varepsilon$$_{r}$＝2.6, H＝1.6〔mm〕( $\pm$0.08), where the width of the radiation patch is identical with that of the ground plane. The resonant frequencies and the return losses were measured by reducing the PSW(Partially Shorted Width) to 0〔mm〕, step by step, when the microstrip line width was 1.47〔mm〕, 2.93〔mm〕and 4.4〔mm〕separately. As a result, a good characterized antenna with a 11% reduced resonant length and a return loss -29.44〔㏈〕 was obtained when the total PSW was in the range of 70% of radiated patch width, compared to the conventional QMSA.A.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.6
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• pp.21-28
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• 2004

This study aims to investigate the effects of partially distributed loads on the dynamic behaviour of steel parabolic arches by using the elasto-plastic finite element model based on the Von Mises yield criteria and the Prandtl-Reuss How rule. For this purpose, the vertical and the radial load conditions were considered as a distributed loading and the loading range is varied from 40% to 100% of arch span. Normal arch and arch with initial deflection were studied. The initial deflection of arch was assumed by the sinusoidal motile of ${\omega}_i\;=\;{\\omega}_O$ sin ($n{\pi}x/L$). Several numerical examples were tested considering symmetric initial deflection when the maximum initial deflection at the apex is fixed as L/1000. The analysis resluts showed that the maximum deflection at the apex of arch was occurred when 70% of arch span was loaded. The maximum deflection at the quarter point of arch span was occurred when 50% of arch span was loaded. It is known that the optimal rise to span ratio between 0.2 and 0.3 when the vertical or radial distributed load is applied. It is verified that the influence of initial deflection of radial load case is more serious than that of vertical load case.

• Journal of Plant Biology
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• v.37 no.3
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• pp.317-323
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• 1994

The calluses formed on the surface of a quarter-girdled Robinia pseudoacacia stems have been shown to originate from immature xylem cells and preexisting cambial cells. The cellus is not only formed by periclinal and anticlinal divisions of radial cells, but also axial cells. In tangential view, the callus at initial stage showed heterogeneous structure composed of long and short cells and then homogeneous one with short cells. Some cells of homogeneous structure in middle region of callus at early stage is later elongated and others mainly divided in trasverse plane. In the result the homogeneous structure becomes into a heterogeneous one. Subsequently, the long cells in heterogeneous structures elongated further and became fusifrom initials, and the short cells divided transversely became ray initials. The appearence of homogeneous and heterogeneous structure in the callus on debarked stem without organ elongation is almost similar to that of the structure in the procambium of young stem which is elongating extensively. Eventually, the ontogeny of vascular cambium in wound callus resembles that of a young stem grown normally, although the debarked stem does not grow in length but in girth and the young stem elongates activity. These findings mean that the active intrusive growth of short procambial cells occurs during the differentiation of fusiform cambial cells.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.160-167
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• 2008

The effects of squealer rim height on three-dimensional flows and aerodynamic losses downstream of a high-turning turbine rotor blade have been investigated for a typical tip gap-to-chord ratio of h/c=2.0%. The squealer rim height-to-chord ratio is changed to be $h_{st}/c$=0.00(plane tip), 1.37, 2.75, 5.51, and 8.26%. Results show that as $h_{st}/c$ increases, the tip leakage vortex tends to be weakened and the interaction between the tip leakage vortex and the passage vortex becomes less severe. The squealer rim height plays an important role in the reduction of aerodynamic loss when $h_{st}/c{\leq}2.75%$. In the case of $h_{st}/c{\geq}5.51%$, higher squealer rim cannot provide an effective reduction in aerodynamic loss. The aerodynamic loss reduction by increasing $h_{st}/c$ is limited only to the near-tip region within a quarter of the span from the casing wall.

• Journal of architectural history
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• v.8 no.4 s.21
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• pp.39-62
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• 1999

Basic concept of this study is that architectural form as a material at present has meaning for the dweller's life on the past historical plane. Main method to recover history is ethnographic interview to dwellers. Secondary method is to analyze ancestors' writings, buildings in the background of the family photos, and past drawings and then to relate them with architectural form at present. Taxonomy is a starting point: general name of the building by outside researcher is quite different from it by inside dwellers. 'Haengrang-chae', servant quarter, has never been used for servants. Function of the haengrang went outside thatched houses at the front village. Firsthand observation or simple analyses as results of several precedent research are reexamined and criticized through this study. The mansion has moaning when we synthesize with the site location based on farming land and tenant farmer, and decline of the Kyongpo Lake. Territoriality of the mansion is reinterpreted to 'In-Out Structure' by Yin-Yang thinking, Dwellers extend buildings gradually to outside village, surrounding rear hills, the lake, DongHae Sea, and finally goes to imaginative Taoist heaven beyond real nature through the literary life. Confucius principle, known to govern upper class house at Yi Dynasty also affect general composition of the buildings: perpetuation of the family by ancestor worship, elder dominance and male dominance, fraternity love in the extended family, charity display by reception of guests, Taoist scholarly life harmonized with nature. However, the study of the particular life and usage of the dwellers reinforces or corrects general supposition of precedent researches. Unique shape of the house has been formed by convenience of the dwellers' life style, early modernized free thought over the rigid Confucius design principle, and female power in male dominant society.

• Journal of The Korean Astronomical Society
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• v.41 no.5
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• pp.121-137
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• 2008

We present optical and near-infrared imaging and long-slit spectroscopy for the blue compact dwarf galaxy (BCD) Mrk 49 in the Virgo Cluster. The surface brightness distribution analysis shows that Mrk 49 consists of an off-centered blue bright compact core of r = 10" and a red faint outer exponential envelope. The $H_{\alpha}$ image and color difference suggest that these two components have different stellar populations: a high surface brightness population of massive young stars and an underlying low surface brightness population of older stars. The redder near-infrared colors of the inner most region suggest that the near-infrared flux of Mrk 49 originates from evolved massive stars associated with the current star-forming activity. The total apparent magnitude is $B_T\;=\;14.32$ mag and the mean effective surface brightness is ${\mu}_{eff}(B)\;=\;21.56$ mag $arcsec^{-2}$. Long-slit spectroscopy shows that Mrk 49 rotates apparently as a solid body within r = 10" in a plane at position angle 55 degrees with an amplitude of about $20\;km\;sec^{-1}$. The measured radial velocity of Mrk 49 was derived as $1,535\;km\;sec^{-1}$; and the total mass of stars and gases is in the range of 3 to $6\;{\times}\;10^9\;M_{\odot}$. The mass-to-light ratios for the central region of Mrk 49 in I and B band are estimated 1.0 and 0.5, respectively. The upper limit of the dark matter to visible matter ratio seems to be < 5. The oxygen abundance is $12\;+\;\log(O/H)\;=\;8.21\;{\pm}\; 0.1$ which is about one quarter of the solar value while the relative helium abundance appears to be similar to that of the sun.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.359-367
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• 2003

Supplementary feeding strategies were evaluated from pre-calving throughout lactation on 24 dual-purpose Mpwapwa breed cows in their second or greater lactation, weighing 246-455 kg. The Mpwapwa breed is an established breed of 4 Bos indicus breeds and 8% of Bos taurus. The cows were penned and stall-fed individually. Eight weeks before calving to eight weeks after calving, the cows were divided into two groups and offered hay ad libitum with either 2 kg DM (L) or 4 kg DM/day (H) concentrates. Nine weeks after calving half of the cows on L-level continued with 2 kg DM/day (L-L) while the remainder received 4 kg DM concentrate daily (L-H). Half of the cows on H-group continued with 4 kg DM/day (H-H) while the remainder received 2 kg DM/day (H-L). The concentrate mixture comprised of sunflower seed cake (33%) and maize bran (67%). The cows consumed all the concentrate offered. Hay DM intake was similar (6.8 kg/day) and tended to decrease the last two weeks before calving increased again after calving. Live weight change and body condition score were similar across treatments before calving but differed after calving (p<0.05). Heavier cows with higher condition score pre-calving had a higher body weight loss and regained weight later. After treatment reallocation, live weight change and condition differed between treatments (p<0.05). Calves were allowed to suckle milk from one quarter. The amount of milk suckled and calf weight gains were not significantly different between treatments. The cows were removed from the experiment when the milk yield was below 4 kg per day. Cows on treatment H produced 6.2 kg and on treatment L 5.0 kg saleable milk/day (p<0.05) during the first 8 weeks post partum. During the period 9-18 weeks post partum the saleable daily milk on H-H, L-H, H-L and L-L were 5.2, 4.8, 4.7 and 4.3 kg, respectively (p>0.05).

• Journal of Advanced Navigation Technology
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• v.16 no.5
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• pp.773-780
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• 2012

ZOR(zeroth order resonance) antenna for 2.45GHz WLAN(wireless local area network) is designed by use of CRLH-TL(composite right left handed transmission line) meta-material. The electrical length of conventional antennas is determined generally according to the resonant frequency, whereas that of ZOR antenna can be determined without reference to the resonant frequency. Therefore ZOR antenna has advantage in miniaturization of antenna in comparison with conventional antennas. In order to design such ZOR antenna, first unit cell with electrical length shorter than a quarter wavelength at 2.45GHz is designed to the some characteristics of homogeneous medium. In order to decrease resonant frequency and enhance frequency bandwidth, the proposed antenna is fed by CPW(co-planar waveguide) and short stub between radiation patch and ground plane is used for obtaining both higher inductance and smaller capacitance than previous mush-room type of CRLH-TL.