• Journal of the Korean Mathematical Society
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• v.42 no.1
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• pp.53-63
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• 2005

Let R be a ring R and ${\sigma}$ be an endomorphism of R. R is called ${\sigma}$-rigid (resp. reduced) if $a{\sigma}r(a) = 0 (resp{\cdot}a^2 = 0)$ for any $a{\in}R$ implies a = 0. An ideal I of R is called a ${\sigma}$-ideal if ${\sigma}(I){\subseteq}I$. R is called ${\sigma}$-quasi-Baer (resp. right (or left) ${\sigma}$-p.q.-Baer) if the right annihilator of every ${\sigma}$-ideal (resp. right (or left) principal ${\sigma}$-ideal) of R is generated by an idempotent of R. In this paper, a skew polynomial ring A = R[$x;{\sigma}$] of a ring R is investigated as follows: For a ${\sigma}$-rigid ring R, (1) R is ${\sigma}$-quasi-Baer if and only if A is quasi-Baer if and only if A is $\={\sigma}$-quasi-Baer for every extended endomorphism $\={\sigma}$ on A of ${\sigma}$ (2) R is right ${\sigma}$-p.q.-Baer if and only if R is ${\sigma}$-p.q.-Baer if and only if A is right p.q.-Baer if and only if A is p.q.-Baer if and only if A is $\={\sigma}$-p.q.-Baer if and only if A is right $\={\sigma}$-p.q.-Baer for every extended endomorphism $\={\sigma}$ on A of ${\sigma}$.

• Journal of Plant Biology
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• v.38 no.4
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• pp.399-407
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• 1995

The effects of 0.5 and 1.0 ppm of ozone on the developing chloroplast of barley (Hordeum vulgare L) seedling during greening were investigated by PSI and II activities, chlorophyll fluorescence, and the contents of chlorophyll. Etiolated barley seedling was treated 0.5 and 1.0 ppm ozone for the first 4 h during greening. In 24 h greening experiment, the contents of chlorophyll were decreased by increasing ozone concentration from 0.5 ppm to 1.0 ppm. In 24 h greening experiment, Fo, Fv, Fm and qE were greatly decreased as the concentration of ozone was increased, but those were not considerably decreased in 48 h greening experiment. In another experiment, the developing barley seedling was treated with 0.5 and 1.0 ppm ozone for the last 4 h during greening period, which was 24 h or 48 h. In both experiments the PS II activity was decreased as the concentration of ozone was increased, but not in PS I activity. Fv, Fm and Fv/Fo were also decreased as the concentration of ozone was increased. qP and qR were strikingly decreased as the concentration of ozone was increased in both experiments.iments.

• Journal for History of Mathematics
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• v.31 no.4
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• pp.183-196
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• 2018

In this study, we propose an approximate method to make Jisuguimundo with magic number 93 to 109. In this method, for two numbers p, q with a relationship of M = 2p+q, we use eight pairs of two numbers with sum p and five pairs of two numbers with sum q. Such numbers must be between 1 and 30. Instead of determining all positions of thirty numbers, this method shows that Jisuguimundo with magic number 93 to 109 can be made by determining positions of thirteen numbers $a_i$(i = 1, 2, ${\cdots}$, 8), $b_5$, $c_i$(i = 1, 2, 3, 4). Method 1 is used to make Jisuguimundo with magic number 93 to 108, and method 2 is used to make Jisuguimundo with magic number 109.

• Communications of the Korean Mathematical Society
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• v.20 no.4
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• pp.645-648
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• 2005

Let K be a Galois extension of a field F with G = Gal(K/F). Let L be an extension of F such that $K\;{\otimes}_F\;L\;=\; N_1\;{\oplus}N_2\;{\oplus}{\cdots}{\oplus}N_k$ with corresponding primitive idempotents $e_1,\;e_2,{\cdots},e_k$, where Ni's are fields. Then G acts on $\{e_1,\;e_2,{\cdots},e_k\}$ transitively and $Gal(N_1/K)\;{\cong}\;\{\sigma\;{\in}\;G\;/\;{\sigma}(e_1)\;=\;e_1\}$. And, let R be a commutative F-algebra, and let P be a prime ideal of R. Let T = $K\;{\otimes}_F\;R$, and suppose there are only finitely many prime ideals $Q_1,\;Q_2,{\cdots},Q_k$ of T with $Q_i\;{\cap}\;R\;=\;P$. Then G acts transitively on $\{Q_1,\;Q_2,{\cdots},Q_k\},\;and\;Gal(qf(T/Q_1)/qf(R/P))\;{\cong}\;\{\sigma{\in}\;G/\;{\sigma}-(Q_1)\;=\;Q_1\}$ where qf($T/Q_1$) is the quotient field of $T/Q_1$.

• Journal of Korean Academy of Nursing
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• v.34 no.5
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• pp.693-701
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• 2004

Purpose: The purpose of this study was to validate Quality of Life Index-Cancer (Q.L.I.-C) developed by Ferrans (1990) among Korean cancer patients. Method: This study design was exploratory factor analysis methodology. Q.L.I.-C was translated into Korean and reverse-translated into English. The subjects were 357 Korean patients with various cancers. Data were collected by questionnaires from May to August, 2000 and was analyzed by descriptive statistics, Principal Component Analysis for construct validity and Cronbach's alpha coefficient for reliability. Result: The range of factor loadings was .446～.841. The explained variance from the 5 extracted factors was 63.7% of the total variance. The first factor 'family' was 35.5%, and 'health & physical functioning', 'psychological', 'spiritual', and 'economic' factors were 11.5%, 6.9%, 5.6%, and 4.2% respectively. Because of cultural difference between Americans and Koreans, certain items such as sexuality, job status, and education were deleted from the extraction of factors in this study. The Cronbach's alpha coefficient was .9253 among the 28 items. Conclusion: Q.L.I.-C could be applied in measuring quality of life of Korean cancer patients. It also recommend to do further studiesfor validation of Q.L.I.-C American and Korean versions relating to cultural differences.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.5
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• pp.356-367
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• 2001

A numerical analysis on branch type sparger in drain tank for depressurization is performed to investigate the flow characteristics due to the change of design factor. As the result of this study, sparger\\`s flow resistance coefficient(K) is 3.53 at the present design condition when engineering margin for surface roughness is considered as 20%, and flow ratio into branch pipe ($Q_s/Q_i$) is 0.41. The correlation for calculating flow resistance coefficients as design factor is presented. Flow resistance coefficient is increased as section area ratio of branch pipe for main pipe and outlet nozzle diameter of main pipe decreasing, but the effects of branch angle and inlet flow rate of main pipe are small. As the change rate of ($Q_s/Q_i$)becomes larger, the change rate of flow resistance coefficient increases. The rate of pressure loss has the largest change as section area ratio changing. The condition of maximum flow resistance in sparger is when the outlet nozzle diameter ratio of main pipe ($D_e/D_i$) is 0.167, the section area ratio ($A_s/A_i$) is 0.1 and the branch angle ($\alpha$) is 55^{\circ}$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6A
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• pp.611-616
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• 2006

In this paper, we propose a practical implementation method of a soft bit decision expression for an R-QAM (Gray coded Rectangular Quadrature Amplitude Modulation) signal based on the Max-Log-MAP algorithm. The parameters of the soft decision expression for the practical implementation can be obtained with simple arithmetic functions associated with some deterministic parameters such as a received value, distances between symbols, and the order of modulation on a signal space. Also, we analyze the performance of an iterative decoding scheme for the QAM signal with I/Q phase unbalance. The unbalance results from the non-ideal characteristic of components such as a phase shifter between in-phase and quadrature paths for quadrature modulator/demondulator.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1B
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• pp.176-182
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• 2010

In this paper, we propose an adaptive I/Q diversity combining scheme which reduces unnecessary computations while maintaining the required performance level. The system with the proposed scheme adaptively applies a proper combining scheme among the conventional selective scheme and combining scheme based on the comparison result between the estimated instantaneous SNR and the pre-determined threshold. As a result, the system with our proposed scheme can reduce the computational load while maintaining the required performance level. Some selected simulation results show that the system with the proposed scheme can decrease the unnecessary computations compared with the system with the conventional schemes while maintaining the required performance level.

• Journal of Applied Biological Chemistry
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• v.64 no.3
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• pp.285-290
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• 2021

Salicornia herbacea is a type of salt marsh plant that has been used in traditional medicine to treat several diseases. Isorhamnetin-3-O-glucoside (I3G) and quercetin-3-O-glucoside (Q3G) are major flavonoids in S. herbacea that are known to exert various pharmacological activities. Therefore, our study sought to validate and optimize an HPLC/UV-based analytical method for I3G and Q3G yield quantification, as well as to determine its limit of detection, limit of quantification, linearity, precision, and accuracy. Upon testing a concentration range of 31.5-1.9 ㎍/mL the results exhibited good linearity (r² ≥0.9996 and r² ≥0.9999 for I3G and Q3G, respectively), and the procedure was deemed precise (relative standard deviation of ≤3.19 and ≤3.85%, respectively), and accurate (102.6-105.0 and 92.9-95.2%, respectively). The results showed that our proposed method could be used for rapid I3G and Q3G evaluation in S. herbacea.

• Bulletin of the Korean Mathematical Society
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• v.26 no.2
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• pp.169-173
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• 1989

Let V={(x,y,z):f=z$^{n}$ -npz+(n-1)q=0 for n .geq. 3} be a compled analytic subvariety of a polydisc in $C^{3}$ where p=p(x,y) and q=q(x,y) are holomorphic near (x,y)=(0,0) and f is an irreducible Weierstrass polynomial in z of multiplicity n. Suppose that V has an isolated singular point at the origin. Recall that the z-discriminant of f is D(f)=c(p$^{n}$ -q$^{n-1}$) for some number c. Suppose that D(f) is square-free. then we prove that by Theorem 2.1 .mu.(p$^{n}$ -q$^{n-1}$)=.mu.(f)-(n-1)+n(n-2)I(p,q)+1 where .mu.(f), .mu. p$^{n}$ -q$^{n-1}$are the corresponding Milnor numbers of f, p$^{n}$ -q$^{n-1}$, respectively and I(p,q) is the intersection number of p and q at the origin. By one of applications suppose that W$_{t}$ ={(x,y,z):g$_{t}$ =z$^{n}$ -np$_{t}$ $^{n-1}$z+(n-1)q$_{t}$ $^{n-1}$=0} is a smooth family of complex analytic varieties near t=0 each of which has an isolated singularity at the origin, satisfying that the z-discriminant of g$_{t}$ , that is, D(g$_{t}$ ) is square-free. If .mu.(g$_{t}$ ) are constant near t=0, then we prove that the family of plane curves, D(g$_{t}$ ) are equisingular and also D(f$_{t}$ ) are equisingular near t=0 where f$_{t}$ =z$^{n}$ -np$_{t}$ z+(n-1)q$_{t}$ =0.}$ =0.