• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.5 no.2
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• pp.67-76
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• 1991

This study showes suitable number of branch circuit and receptacle in residential apartments and houses by surveying and analyzing using practic of consents and domestic electic machinery, layout of indoor furniture This results will offer optimum design of wiring equipment, increse saftety and convienience when residents use domestic electic machinery and interior wiring devices.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.67-74
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• 2005

Fluid flow and heat transfer in rectangular duct system are measured and computed by commercial software of Star-CD for comparison between them. Three rectangular systems are investigated in this study. Those are a rectangular duct with 90 degree bended elbow, a rectangular duct with two branchs, and a circular cylinder in a rectangular duct. But heat transfer is studied only for last system. These investigations show us that the numerical solutions predict satisfactorily design factors (K-factor for the elbowed duct, distributions of flow rates into each branch from a duct, and Nusselt number around circular cylinder) even though there are some disagreements in velocity profiles and turbulent kinetic energy.

• Bulletin of the Korean Mathematical Society
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• v.53 no.3
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• pp.651-656
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• 2016

Let G be a finite group and nse(G) be the set of numbers of elements of G of the same order. In this paper, we prove that the simple group $Sz(2^{2m+1})$, where $2^{2m+1}-1$ is a prime number, is uniquely determined by $nse(Sz(2^{2m+1}))$ and ${\mid}Sz(2^{2m+1}){\mid}$.

• ETRI Journal
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• v.29 no.6
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• pp.716-724
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• 2007

As ultra-wideband impulse radio (UWB-IR) uses short-duration impulse signals of nanoseconds, even a small number of timing errors can cause a detrimental effect on system performance. A delay-locked loop (DLL) is proposed to synchronize and reduce timing errors. The design of the DLL is vital for UWB systems. In this paper, an improved DLL is introduced to a UWB-IR time-hopping spread-spectrum system. Instead of using only two central correlator branches as in a conventional DLL, the proposed system uses two additional correlator branches with different delay parameters and different weight parameters. The performance of the proposed schemes with the optimal parameters is compared with that of traditional schemes through simulation: the proposed four-branch DLLs achieves less tracking jitter or a longer mean time to lose lock (MTLL) than the conventional two-branch DLLs if proper parameters are chosen.

• The Journal of the Acoustical Society of Korea
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• v.21 no.3E
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• pp.105-111
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• 2002

The parabolic equation technique provides an excellent model to describe the wave phenomena when there exists a predominant direction of propagation. The model handles the square root wave number operator in paraxial direction. Realization of the pseudo-differential square root operator is the essential part of the parabolic equation method for its numerical accuracy. The wide-angled approximation of the operator is made based on the Pade series expansion, where the branch line rotation scheme can be combined with the original Pade approximation to stabilize its computational performance for complex modes. The Galerkin integration has been employed to discretize the depth-dependent operator. The benchmark tests involving the half-infinite space, the range independent and dependent environment will validate the implemented numerical model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.473-476
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• 2000

Recently, many studies focus on mixed-mode fatigue-fracture characteristics of characteristics of materials. In order to reveal crack initiation and propagation mechanisms in combined -mode fatigue. This paper investigates the initiation and propagation behavior of the fatigue crack of the STS304 specimens under mixed mode loading conditions. moreover crack arrest and branch phenomena were analyzed with respect to the change do the angle of inclined loading. The relationship between the angle of inclined loading and the angle of branched crack was studied. A greate number of cycles are necessary to initiate a new crack from the initial crack. The direction of the new crack propagation is determined by MTS theory.

• Journal of electromagnetic engineering and science
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• v.7 no.3
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• pp.109-115
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• 2007

The performances of M-ary PSK(MPSK) systems using L-branch maximum ratio combining(MRC) diversity reception in frequency-nonselective slow Rician fading channels are derived theoretically. Especially we investigate the effect of number of symbols on the difference between the approximation to bit error probability and the exact bit error rate(BER) in evaluating the performance of MPSK signals through numerical analyses. On the other hand, when M-ary DPSK(MDPSK) signals experience the Rician fading channels, the general formula for evaluating BER of MDPSK signals in the independent branch diversity system is presented using the integral-form expressions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12A
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• pp.1983-1989
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• 2001

A new two-step soft output Viterbi algorithm (SOVA) for turbo decoder is proposed and analyzed in 7his paper. Due to the algebraic structure of the proposed algorithm, slate and branch metrics can be obtained wish parallel processing using matrix arithmetic. As a result, the number of multiplications to calculate state metrics of each stage and total memory size can be decreased tremendously. Therefore, it can be expected that the proposed algebraic two-step SOVA is suitable for applications in which low computational complexity and memory size are essential.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.165-168
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• 2002

This paper describes the dynamics of the weak shock wave propagating inside some kinds of branched pipe bends. Computations are carried out by solving the two-dimensional, compressible, unsteady Euler Equations. The second-order TVD(Total Variation Diminishing) scheme is employed to discretize the governing equations. For computations, two types of branched pipe($90^{\circ}$ branch,$45^{\circ}$ branch) with a diameter of D are used. The incident normal shock wave is assumed at D upstream of the pipe bend entrance, and its Mach number is changed between 1.1 and 2.4. The flow fields are numerically visualized by using the pressure contours and computed schlieren images. The comparison with the experimental data performed for the purpose of validation of computational work. Reflection and diffraction of the propagating shock wave are clarified. The present computations predicted the experimented flow field with a good accuracy.

• Korean Journal of Veterinary Research
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• v.31 no.4
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• pp.515-518
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• 1991

A field study of Lymnaea viridis, the intermediate host of Fasciola hepatica, was carried out in the eastern Chonnam area. The snail was distributed all over the place. Their major habitats were rice paddies (60.8%), followed by brooks (23.2%), irrigation canals (8.6%), and drains (5.6%). Other minor habitats included natural ponds (1.5%), lakes (0.4%), and rivers (0.1%). L. viridis was living in wet clay soil, occasionally entering water. The snails discharged egg masses when the temperature was $15{\sim}20^{\circ}C$, and the number of the snails was the highest late in October. At $9^{\circ}C$ the snails were not found on the mud: they were present deep in water or at the base of rice stubbles. These hibernation sites were discussed with the epidemiology of fascioliasis.