• East Asian mathematical journal
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• v.17 no.2
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• pp.225-232
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• 2001

Let R be a prime ring with characteristic not two. U a (${\sigma},{\tau}$)-left Lie ideal of R and d : R$\rightarrow$R a non-zero derivation. The purpose of this paper is to invesitigate identities satisfied on prime rings. We prove the following results: (1) [d(R),a]=0$\Leftrightarrow$d([R,a])=0. (2) if $(R,a)_{{\sigma},{\tau}}$=0 then $a{\in}Z$. (3) if $(R,a)_{{\sigma},{\tau}}{\subset}C_{{\sigma},{\tau}}$ then $a{\in}Z$. (4) if $(U,a){\subset}Z$ then $a^2{\in}Z\;or\;{\sigma}(u)+{\tau}(u){\in}Z$, for all $u{\in}U$. (5) if $(U,R)_{{\sigma},{\tau}}{\subset}C_{{\sigma},{\tau}}$ then $U{\subset}Z$.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.371-377
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• 2014

Characteristics of holdup and flow behavior of fluidized solid particles were investigated in a liquid-solid circulating fluidized bed ($0.102m{\times}3.5m$). Effects of liquid velocity ($U_L$), particle size ($d_P$) and solid circulation rate ($G_S$) on the solid holdup, overall particle rising velocity, slip velocity between liquid and particles and hydrodynamic energy dissipation rate in the riser were examined. The particle holdup increased with increasing $d_P$ or $G_S$ but decreased with increasing $U_L$. The overall particle rising velocity increased with increasing $U_L$ or $G_S$ but decreased with increasing $d_P$. The slip velocity increased with increasing $U_L$ or $d_P$ but did not change considerably with $G_S$. The energy dissipation rate, which was found to be closely related to the contacting frequency of micro eddies, increased with increasing $d_P$, $G_S$ or $U_L$. The solid particle holdup was well correlated with operating variables such as $U_L$, $d_P$ and $G_S$.

• Fashion & Textile Research Journal
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• v.10 no.5
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• pp.676-682
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• 2008

In this study a guideline of the 3D-fit pattern for the ECG(electrocardiogram) measurement of elderly's u-healthcare clothes was proposed. In the screening test of the ECG measurement band, ECG peak band was observable at the band pressure of 0.20 kPa. By employing a 3D body image, tight-fit 3D patterns were made at two different reduction rates of 21%(pattern 1) and 33%(pattern 2), and corresponding pressure of both of the clothes were 0.25 kPa and 0.54 kPa, respectively. Typical waves of ECG were found in both stationary and moving position. In terms of the subjective evaluation of the u-healthcare clothes when worn, it was confirmed that reduction pattern 1(0.25 kPa) conveyed comfortable clothing pressure and pleasantness, which is very close to the result of screening test of ECG band experiment. As results, it is recommended that reduction rate should be adjusted, so that clothing pressure is about 0.2 kPa for the elderly's comfortable and efficient u-healthcare clothes.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.148-151
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• 2009

u-GIS 공간정보를 제공하기 위한 3D 모델의 렌더링 성능을 향상시키기 위해 일반적으로 Discrete LOD 기법이 적용된다. 하지만 u-GIS의 3D 건물 모델은 그 복잡성이 매우 높아 LOD 단계별로 모델을 직접 생성하려면 많은 비용과 시간이 소요되어 효율적이지 못하다. 본 연구에서는 원본 3D 모델을 활용하여 하위 LOD 단계의 모델을 메쉬 간략화 알고리즘인 QEM 기법을 통해 생성하는 프로그램을 구현하였다. 프로그램은 다양한 3D 모델의 데이터 포맷을 입력받고 출력할 수 있도록 하여 범용성을 높이고, 생성되는 모델의 결과를 바로 화면으로 확인할 수 있도록 하여 사용자 편의성을 확보하였다. 몇 개의 실제 3D 건물 모델로 실험을 수행하여 프로그램의 성능을 검증하고 그 결과를 도출하였다.

• Korean Journal of Mathematics
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• v.20 no.4
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• pp.371-379
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• 2012

Let D be an integral domain, $\bar{D}$ be the integral closure of D, * be a star operation of finite character on D, $*_w$ be the so-called $*_w$-operation on D induced by *, X be an indeterminate over D, $N_*=\{f{\in}D[X]{\mid}c(f)^*=D\}$, and $Kr(D,*)=\{0\}{\cup}\{\frac{f}{g}{\mid}0{\neq}f,\;g{\in}D[X]$ and there is an $0{\neq}h{\in}D[X]$ such that $(c(f)c(h))^*{\subseteq}(c(g)c(h))^*$}. In this paper, we show that D is a *-quasi-Pr$\ddot{u}$fer domain if and only if $\bar{D}[X]_{N_*}=Kr(D,*_w)$. As a corollary, we recover Fontana-Jara-Santos's result that D is a Pr$\ddot{u}$fer *-multiplication domain if and only if $D[X]_{N_*} = Kr(D,*_w)$.

• Bulletin of the Korean Mathematical Society
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• v.49 no.4
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• pp.767-774
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• 2012

For a positive square-free integer $d$, let $t_d$ and $u_d$ be positive integers such that ${\epsilon}_d=\frac{t_d+u_d{\sqrt{d}}}{\sigma}$ is the fundamental unit of the real quadratic field $\mathbb{Q}(\sqrt{d})$, where ${\sigma}=2$ if $d{\equiv}1$ (mod 4) and ${\sigma}=1$ otherwise For a given positive integer $l$ and a palindromic sequence of positive integers $a_1$, ${\ldots}$, $a_{l-1}$, we define the set $S(l;a_1,{\ldots},a_{l-1})$ := {$d{\in}\mathbb{Z}|d$ > 0, $\sqrt{d}=[a_0,\overline{a_1,{\ldots},2a_0}]$}. We prove that $u_d$ < $d$ for all square-free integer $d{\in}S(l;a_1,{\ldots},a_{l-1})$ with one possible exception and apply it to Ankeny-Artin-Chowla conjecture and Mordell conjecture.

• Journal of the Chungcheong Mathematical Society
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• v.19 no.3
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• pp.213-218
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• 2006

The 2D g-Navier-Stokes equations are a certain modified Navier-Stokes equations and have the following form, $$\frac{{\partial}u}{{\partial}t}-{\nu}{\Delta}u+(u{\cdot}{\nabla})u+{\nabla}p=f$$, in ${\Omega}$ with the continuity equation ${\nabla}{\cdot}(gu)=0$, in ${\Omega}$, where g is a suitable smooth real valued function. In this paper, we will derive 2D g-Navier-Stokes equations from 3D Navier-Stokes equations. In addition, we will see the relationship between two equations.

• Journal of Korea Water Resources Association
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• v.54 no.5
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• pp.301-309
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• 2021

In this study, we tried to improve the performance of the existing U-net-based deep learning rainfall prediction model, which can weaken the meaning of time series order. For this, ConvLSTM2D U-Net structure model considering temporal consistency of data was applied, and we evaluated accuracy of the ConvLSTM2D U-Net model using a RainNet model and an extrapolation-based advection model. In addition, we tried to improve the uncertainty in the model training process by performing learning not only with a single model but also with 10 ensemble models. The trained neural network rainfall prediction model was optimized to generate 10-minute advance prediction data using four consecutive data of the past 30 minutes from the present. The results of deep learning rainfall prediction models are difficult to identify schematically distinct differences, but with ConvLSTM2D U-Net, the magnitude of the prediction error is the smallest and the location of rainfall is relatively accurate. In particular, the ensemble ConvLSTM2D U-Net showed high CSI, low MAE, and a narrow error range, and predicted rainfall more accurately and stable prediction performance than other models. However, the prediction performance for a specific point was very low compared to the prediction performance for the entire area, and the deep learning rainfall prediction model also had limitations. Through this study, it was confirmed that the ConvLSTM2D U-Net neural network structure to account for the change of time could increase the prediction accuracy, but there is still a limitation of the convolution deep neural network model due to spatial smoothing in the strong rainfall region or detailed rainfall prediction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.1
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• pp.141-148
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• 1998

This study describes the effects of 1,25-dihydroxyvitamin D3[1,25(OH)2D3, calcitriol] analog, 1,25(OH)2-16ene-23yne-D3 on proliferatin and differentiatin of the human histiocytic lymphoma cell line U937. This paper also describes the effects of 1,25(OH)2-16ene-23yne-D3 on ${\gamma}$-interferon(IFN-${\gamma}$) synthesis by phytohemagglutinin-activated peripheral blood lymphocytes(PBLs). In the present investigation, 1,25(OH2)-16ene-23yne-D3 was compared to the natural metablite of vitamin D3, 1,25(OH)2D3. 1,25(OH)2-16ene-23yne-D3 was more potent than 1,25(OH)2D3 for inhibition of proliferation and induction of differentiation of U937 cells, Its effects on inhibition of proliferation was about 30-fold more potent than 1,25(OH)2D3. On induction of differentiation as measured by nonspecific esterase (NSE) activity and morphologic change, this analog morphologically and functionally differentiated U937 cells to monocyte-macrophage phenotype showing a decrease of N/C ration in Giemsa staining and the increase of adherence ability of surface. After 3 days in culture, a more significant supression of IFN-${\gamma}$ synthesis analog on supression of IFN-${\gamma}$ synthesis was a dose-dependent manner, with peak activity at 10-7M. The strong direct effects of 1,25(OH)2-16ene-23yne-D3 on cell proliferation and cell differentiation, make this compound an interesting candidate for clinical studies for several types of malignancies, and the effects on supression of IFN-${\gamma}$ synthesis provide the further evidence for a role of 1,25(OH)2-16ene-23yne-D3 in immunoregulation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.5
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• pp.480-492
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• 2009

In this paper, we proposed a broadband U-shaped RFID tag antenna with near-isotropic characteristic at UHF band. The proposed tag antenna is composed of the U-shaped half wavelength dipole and a rectangular shaped feed. The rectangular shaped feed that is located inside U-shaped dipole is connected for conjugate impedance matching with the commercial tag chip. A better constant gain deviation characteristic in the operating frequency band is achieved by inserting a rectangular slit in the lower center of the U-shaped antenna body. On the condition of VSWR<2, the tag antenna had the measured bandwidth of 10.36%, from 860.5 to 954.5 MHz, and 9.84%, from 864.5 to 954 MHz, for antenna without slit and with slit, respectively. On the condition of VSWR<5.8, the tag antennas had the measured bandwidth of 15.78%, from 835.5 to 979.5 MHz, and 15.89%, from 837 to 981.5 MHz, for antenna without slit and with slit, respectively. The difference between the maximum and minimum gain deviations of tag antenna without slit in the operating frequency band is 0.53 dB since the maximum and minimum gain deviations are 3.86 dB and 3.33 dB, respectively. Whereas the difference between the maximum and minimum gain deviations of tag antenna with slit in the operating frequency is 0.06 dB since the maximum and minimum gain deviations are 3.60 dB and 3.54 dB, respectively.