• Journal of the Korean Mathematical Society
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• v.58 no.5
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• pp.1109-1129
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• 2021

This paper considers an anisotropic polytropic infiltration equation with a source term $$u_t={\sum\limits_{i=1}^{N}}{\frac{{\partial}}{{\partial}x_i}}\(a_1(x){\mid}u{\mid}^{{\alpha}_i}{\mid}u_{x_i}{\mid}^{p_i-2}u_{x_i}\)+f(x,t,u)$$, where p_i > 1, α_i > 0, a_i(x) ≥ 0. The existence of weak solution is proved by parabolically regularized method. Based on local integrability $u_{x_i}{\in}W_{loc}^{1,p_i}(\Omega)$, the stability of weak solutions is proved without boundary value condition by the weak characteristic function method. One of the essential characteristics of an anisotropic equation different from an isotropic equation is found originally.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.951-956
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• 2011

As the evaluation of loading characteristic on tilting mechanism is the most important one of the function test of tilting mechanism, the changing characteristic of load must be investigated on tilting of carbody for both the static and running condition of train. In this study, we reduced the load of tilting mechanism by adjusting the interface of carbody and bogie such as the weight balance, level of underframe, height of leveling valve, height of axle box and center position of tilting actuator with the characteristic curve of load for optimal condition of the tilting mechanism obtained in the previous study. Furthermore, the factor and effect of the interfacial structures respecting the load of tilting mechanism was evaluated by analyzing the changing characteristic of load obtained in the process of adjustment of interfaces. From these data, we will propose the maintenance standards for interfacial structures and tilting mechanism in order to minimize the load of tilting mechanism by analyzing in detail the characteristic of load for the main factors of the interfacial structure effecting on the load of tilting mechanism.

• Communications of the Korean Mathematical Society
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• v.26 no.4
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• pp.669-684
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• 2011

In this note, we obtain the expression of the characteristic fucntion of the random variable $\int_o^TB_s^{{\alpha},{\beta}}dB_s^{H,K}$, where $B^{{\alpha},{\beta}}$ and $B^{H,K}$ are two independent bifractional Brownian motions with indices ${\alpha}{\in}(0,1),{\beta}{\in}(0, 1]$ and $HK{\in}(\frac{1}{2},\;1)$ respectively.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.42-45
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• 2002

A novel characteristic value extraction method based on morphological spatial frequency is proposed. Morphological spatial frequency defined by morphological pattern distribution function is introduced. Superiority of the method was proved for various images by experiment. Furthermore the fact that the proposed method does not need threshold to obtain binary image provides its applicability to content-based image retrieval.

• Journal of the Korean Mathematical Society
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• v.35 no.3
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• pp.637-658
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• 1998

One-dimensional diffusion processes are characterized by Feller's data of canonical scales and speed measures and, if we apply the theory of spectral functions of strings developed by M. G. Krein, Feller's data are determined by paris of spectral characteristic functions so that theses pairs may be considered as invariants of diffusions under the homeomorphic change of state spaces. We show by examples how these invariants are useful in the study of one-dimensional diffusion processes.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.325-330
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• 2000

In general steel sheet pile use the containment system, vertical barrier systems for waste disposal and landfill purposes, roads in excavation which have a more permanent character or temporary structure. The sheet pile joints between section of the wall are sealed with a filter material arid the resistance to seepage is a function of the type of material employed. The aim of this paper is to review a characteristic of permeability for Z type sheet pile by field test in various condition.

• Journal for History of Mathematics
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• v.15 no.1
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• pp.147-168
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• 2002

In this paper, we introduce the arrangement of hyperplanes and the graph theory. In particular, we explain how to study the 4-color problem by using characteristic polynomials of the arrangement of hyperplanes. The 4-color problem was appeared in 1852 at first and Appel and Haken proved it by using computer in 1976. The arrangement of hyperplanes induced from a graph is called a graphic arrangement. Graphic arrangement is a subarrangement of Braid arrangement. Thus the chromatic function of a graph is equal to the characteristic polynomial of a graphic arrangement. If we use this result, we can apply the theory of the arrangement of hyperplanes to the study for the chromatic functions.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.241-245
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• 2001

In this study, we designed irrigation channel which meet function of waterquality purification and landscape as well as waterquantity using planting in Sanggye-ri Yeomsan-myeon Yeounggwang-gun Jeollanam-do. First, according to hydrology characteristic, irrigation channel is designed dividing three zone flood control zone, river-friendliness facilities zone and naturally favorable zone. Second, for designing planting, criterion of selecting plant is established. As a result, we designed planting dividing segment to harmony regional characteristic and landscape.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.597-602
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• 1987

This paper proposes a voltage-fed high frequency resonant inverter having variable voltage variable frequency(VVVF) control function. VVVF control is performed by PWM-TRC method in the boost type chopper and PFM-TRC method in the high frequency resonant inverter. This circuit is suitable for induction heating and melting power supply in industry. The operating characteristics of this inverter are discussed from a theoretical point of view. The results of operating characteristic analyses are given leading to complete designing data.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.12 no.1
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• pp.25-32
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• 2008

A pin fin is optimized based on the increasing rate of heat loss by using a two-dimensional analytic method. The optimum heat loss, corresponding optimum thermal resistance and fin length are presented as a function of the fin base thickness, convection characteristic numbers ratio, fin outer radius and ambient convection characteristic number. One of the results shows that both the optimum heat loss and fin length decrease linearly whereas the optimum thermal resistance increases very slightly with increase of the fin base thickness.