• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.40.1-40
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• 2003

• Journal of the Korean Mathematical Society
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• v.52 no.4
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• pp.685-697
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• 2015

For a field K, a square-free monomial ideal I of K[$x_1$, . . ., $x_n$] is called an f-ideal, if both its facet complex and Stanley-Reisner complex have the same f-vector. Furthermore, for an f-ideal I, if all monomials in the minimal generating set G(I) have the same degree d, then I is called an $(n, d)^{th}$ f-ideal. In this paper, we prove the existence of $(n, d)^{th}$ f-ideal for $d{\geq}2$ and $n{\geq}d+2$, and we also give some algorithms to construct $(n, d)^{th}$ f-ideals.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.43-48
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• 2012

This paper presents an iterative single-frequency continuous-wave signal-based I/Q regeneration method for improving image-rejection performance of multi-port junction-based direct receivers (MPDRs). This paper analyzes I/Q regeneration in MPDRs as I/Q mismatch compensation for direct conversion receivers. Based on the analysis, this paper evaluates the accuracy of I/Q regeneration in terms of the image-rejection ratio (IRR). The proposed method improves the IRR performance more than 20 dB compared to existing I/Q regeneration methods. Simulation results show that MPDRs using the proposed method can achieve an IRR of more than 70 dB, and that the bit error rate performances are almost the same as those of conventional coherent demodulators, even in fading channels.

• Journal of the Korean Mathematical Society
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• v.15 no.1
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• pp.59-61
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• 1978

Let $X_1$, $X_2$, ${\cdots}$, $X_n$ be i.i.d. uniform (0,1) random variables. Let $f_n(x)$ denote the probability density function (p.d.f.) of $T_n={\sum}^n_{i=1}X_i$. Consider a set S(x ; ${\delta}$) of lattice points defined by S(x ; ${\delta}$) = $x{\mid}x={\delta}+j$, j=0, 1, ${\cdots}$, n-1, $0{\leq}{\delta}{\leq}1$} The lattice distribution induced by the p.d.f. of $T_n$ is defined as follow: (1) $f_n^{(\delta)}(x)=\{f_n(x)\;if\;x{\in}S(x;{\delta})\\0\;otherwise.$. In this paper we show that $f_n{^{(\delta)}}(x)$ is a probability function thus we obtain a family of lattice distributions {$f_n{^{(\delta)}}(x)$ : $0{\leq}{\delta}{\leq}1$}, that the mean and variance of the lattice distributions are independent of ${\delta}$.

• Korean Journal of Biological Psychiatry
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• v.23 no.4
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• pp.140-147
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• 2016

Objectives To determine the relationship between the Alu insertion/deletion (I/D) polymorphism in the tissue-type plasminogen activator (tPA) gene and the clinical outcome of mirtazapine treatment in Korean major depressive disorder (MDD) patients. Methods We enrolled 422 patients in this study. Symptoms were evaluated using the 21-item Hamilton Depression Rating (HAMD-21) Scale. After 1, 2, 4, and 8 weeks of mirtazapine treatment, the association between the Alu I/D polymorphism in the tPA gene and remission/response outcomes were evaluated. Results The proportion of I/I homozygotes in responders was higher than that in non-responders, whereas the proportion of D/D homozygotes in responders was lower than that in non-responders at 8 weeks of treatment (p = 0.032, OR = 1.57). The percentage decline of HAMD-21 scores in I allele carriers was larger than that of D/D homozygotes at 2 and 8 weeks of treatment (p = 0.035 and 0.007, respectively). I allele carriers were associated with remission at 8 weeks of treatment (p = 0.047, OR = 2.2). Conclusions These results show that treatment response and remission to mirtazapine were associated with the Alu I/D polymorphism of the tPA gene. This suggests the Alu I/D polymorphism may be a potential genetic marker for the prediction of therapeutic response to mirtazapine treatment in patients with MDD.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1027-1035
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• 2013

In this study, two rainfall patterns are utilized for practical consideration of rainfall phenomena in unsaturated soil slope design. One is the I.D.F (Intensity-Duration-Frequency) method which is an existing design rainfall method and ignores the effect of the variation of the rainfall according to the time. The other is the Huff method which considers this effect oppositely. First, the safety of factor of the slope according to the variation of an initial suction which means the precedent rainfall effect was examined by means of the application of the I.D.F method. Through the application of two rainfall patterns, it was discussed how the rainfall pattern affects the factor of safety of the slope. As a result, it is found that the Huff method is more practical on the evaluation of the slope stability than the I.D.F method.

• Bulletin of the Korean Mathematical Society
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• v.46 no.2
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• pp.235-243
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• 2009

In this paper we will investigate the superstability of the generalized d'Alembert type functional equations ${\sum}^m_{i=1}f(x+{{\sigma}^i}(y))$ = kg(x)f(y) and ${\sum}^m_{i=1}f(x+{{\sigma}^i}(y))$ = kf(x)g(y).

• Journal of the Korean Institute of Navigation
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• v.9 no.2
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• pp.13-26
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• 1985

The purpsoe of automatic steering system is to keep the ship's course stable with the minimum course error and rudder angle, and there have been a number of studies as to the optimal design and adjustment of the autopilot. Recently, modern control theories are being used widely in analyzing and designing the system. When a ship is at sea, autopilot installed on the ship plays an important role, particularly in the respect of economic aspects, that is, when the design and the adjustment of adjustable parameters are not conducted perfectly, the amount of loss in energy and the extension of sailing distance become large. Therefore the optimal design and adjustment of a autopilot are very important. Though P.I.D type autopilots are widely spread and generally used in modern ships, the suitability and the adjusting method are not clarified. In this paper the authors considered the stabilaity and the economical efficiency of the P.I.D. type autopilot and investigated various facts which should be considered at the time of designing and using the P.I.D. type autopilot through the digital computer simulation.

• Journal of Advanced Marine Engineering and Technology
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• v.19 no.3
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• pp.9-23
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• 1995

To analyze the spray and flame in D.I. diesel engine, the visualizing methods by schlieren photograph and diffused background illumination photograph with high speed camera are applied to optically accessible D.I.diesel engine. Wcaporating spray, spray droplets and brightness flame are taken with high speed camera by visuallizing method in accordance with various suction air temperature and injection time. The spray and flame image on the film was analyzed by image analyzer. The optically accessible D.I. diesel engine had the similar pressure characteristic to the real D.I. diesel engine. Experimental results showed that shadow areas of the evaporating spray were extended at higher suction air temperature, spray droplets had a max. Penetration length and their penetrating patterns were dependent on the surrounding gas temperature, and flame size after ignition was largely governed by the evaporated fuel quantity at ignition point and by the surrounding gas condition due to piston motion.

• Journal of the Korea Safety Management & Science
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• v.10 no.3
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• pp.267-274
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• 2008

This paper reports generating creative ideas based on customer needs using Kano Model and Importance-Differentiation Matrix (I-D Matrix). Nowadays, every customer demands creative ideas on product innovations in order to be satisfied her needs. However, most existing methods are limited to get creative ideas that reflect customer needs. Any creative ideas that do not fully reflect customer needs are obviously more difficult to succeed in the market than those that reflect customer needs. This paper distinguishes each quality elements the customer needs in terms of Kano Model. And it presents the effective ways of generating creative ideas by I-D Matrix in order to overcome current uppermost limits.