• Bulletin of the Korean Mathematical Society
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• v.59 no.3
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• pp.617-642
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• 2022

For positive integers n and d with d < n, an n × n array A based on 𝒳 = {0, 1, …, nd} is called a sparse anti-magic square of order n with density d, denoted by SAMS(n, d), if each non-zero element of X occurs exactly once in A, and its row-sums, column-sums and two main diagonal-sums constitute a set of 2n + 2 consecutive integers. An SAMS(n, d) is called regular if there are exactly d non-zero elements in each row, each column and each main diagonal. In this paper, we investigate the existence of regular sparse anti-magic squares of order n ≡ 1, 5 (mod 6), and prove that there exists a regular SAMS(n, d) for any n ≥ 5, n ≡ 1, 5 (mod 6) and d with 2 ≤ d ≤ n - 1.

• Korean Journal of Mathematics
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• v.18 no.1
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• pp.37-43
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• 2010

Let D be an integral domain, X be an indeterminate over D, and $N_v=\{f{\in}D[X]{\mid}(A_f)_v=D\}$. In this paper, we introduce the concept of t-locally divided domains, and we then prove that $D[X]_{N_v}$ is a locally divided domain if and only if D is a t-locally divided UMT-domain, if and only if D[X] is a t-locally divided domain.

• Journal of Nutrition and Health
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• v.21 no.2
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• pp.129-133
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• 1988

The lonitudinal determination of specific gravity, total solid and protein contents of human milk were carried out in 27 Korean women. Human milk samples from the subjects were collected at 15, 30, 60, 90, 120, 150th days of lactation. 1) The average values of specific gravity of the milk was 1, 0281 (S.D. 0.0018, n=12), with a range of 1.0200-1.0383. 2) The average values of total soild of the milk was 12.07g/100ml(S.D. 0.38, n=112), with a range of 9.36-15.88g/100ml. 3) The average values of protein content of the milk was 1.20g/100ml (S.D. 0.14, n=112), with a range of 1.09-1.46g/100ml. A slight decrease of specific gravity and protein content in human milk was found during the course of lactation, but significant decrease was not found in total solid content.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.1
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• pp.58-63
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• 2013

Using the known result of the expected busy period for the triadic Med (N, T, D) operating policies applied to a controllable M/G/1 queueing model, its upper and lower bounds are derived to approximate its corresponding actual values. Both bounds are represented in terms of the expected busy periods for the dyadic Min (N, T), Min (N, D) and Min (T, D) or Max (N, T), Max (N, D) and Max (T, D) with the simple N, T and D operating policies without using any other types of triadic operating policies such as Min (N, T, D) and Max (N, T, D) policies. All three input variables N, T and D are equally contributed to construct such bounds for estimation of the expected busy period.

• Journal of the Korean Mathematical Society
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• v.46 no.1
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• pp.41-49
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• 2009

Let $\zeta$ be a fixed complex number. In this paper, we study the quantity $S(\zeta,\;n):=mas_{f{\in}{\Lambda}_n}\;|f(\zeta)|$, where ${\Lambda}_n$ is the set of all real polynomials of degree at most n-1 with coefficients in the interval [0, 1]. We first show how, in principle, for any given ${\zeta}\;{\in}\;{\mathbb{C}}$ and $n\;{\in}\;{\mathbb{N}}$, the quantity S($\zeta$, n) can be calculated. Then we compute the limit $lim_{n{\rightarrow}{\infty}}\;S(\zeta,\;n)/n$ for every ${\zeta}\;{\in}\;{\mathbb{C}}$ of modulus 1. It is equal to 1/$\pi$ if $\zeta$ is not a root of unity. If $\zeta\;=\;\exp(2{\pi}ik/d)$, where $d\;{\in}\;{\mathbb{N}}$ and k $\in$ [1, d-1] is an integer satisfying gcd(k, d) = 1, then the answer depends on the parity of d. More precisely, the limit is 1, 1/(d sin($\pi$/d)) and 1/(2d sin($\pi$/2d)) for d = 1, d even and d > 1 odd, respectively.

• Journal of Life Science
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• v.18 no.6
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• pp.782-788
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• 2008

The aim of this work is to show differences in the pattern of glycoconjugate composition in the intestines of four teleostean species (Sebastes schlegeli, Halichoeres poecilopterus, Bryzoichthys lysimus, and Takifugu pardalis). We compared four regions of all species studied. The specimens were processed and stained with nine kinds of biotinylated lectins (DBA, SBA, PNA, BSL- I , RCA- I , sWGA, UEA- I , LCA and Con A). Except for Sebastes schlegeli, no differences between regions were observed. The intestinal epithelium of Halichoeres poecilopterus possessed D-glucose/mannose residues in all regions. ${\beta}$-N-acetyl-D-galactosamine was distinctive along the intestines, although the pattern of diversity was different in Sebastes schlegeli, Bryzoichthys lysimus, and Takifugu pardalis. Additionally, the occurrence of Galactose-${\beta}$-1,3-N-acetyl-D-galactosamine and ${\alpha}$-D-galactose were confirmed in the proximal, middle, and distal intestine of Sebastes schlegeli, while rectal intestine lacked these sugar residues. Along with ${\beta}$-N-acetyl-D-galactosamine, ${\beta}$-N-acetyl-D-glucosamine and D-glucose/mannose were also determined in Bryzoichthys lysimus. Galactose-${\beta}$-1,3-N-acetyl-D-galactosamine, D-galactose, and D-glucose/mannose were also present in Takifugu pardalis.

• Journal of the Korean Mathematical Society
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• v.33 no.4
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• pp.801-811
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• 1996

Let $Z^d$ denote the set of all d-tuples of integers$(d \geq 1, a positive integer)$. The points in $Z^d$ will be denoted by $\underline{m},\underline{n}$, etc., or sometime, when necessary, more explicitly by $(m_1, m_2, \cdots, m_d)$, $(n_1, n_2, \cdots, n_d)$ etc. $Z^d$ is partially ordered by stipulating $\underline{m} \underline{<}\underline{n} iff m_i \leq n_i$ for each i, $1 \leq i \leq d$.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.3
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• pp.63-70
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• 2010

Based on the known results of the expected busy periods for the triadic Min (N, T, D) and Max (N, T, D) operating policies applied to a controllable M/G/1 queueing model, a relation between them is constructed. Such relation is represented in terms of the expected busy periods for the simple N, T and D, and the dyadic Min (N, T), Min (T, D) and Min (N, D) operating policies. Hence, if any system characteristics for one of the two triadic operating policies are known, unknown corresponding system characteristics for the other triadic operating policy could be obtained easily from the constructed relation.

• Journal of IKEEE
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• v.28 no.1
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• pp.33-37
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• 2024

In this paper, we report the design and the measurement of a X-band low noise amplifier (LNA) monolithic microwave integrated circuit (MMIC) using a 0.25 ㎛ gate length microstrip GaN-on-SiC high electron mobility transistor (HEMT) technology. The developed X-band GaN-based LNA MMIC achieves small signal gain of 22.75 dB ~ 25.14 dB and noise figure of 1.84 dB ~ 1.94 dB in the desired band of 9 GHz to 10 GHz. Input and output return loss values are -11.36 dB ~ -24.49 dB and -11.11 dB ~ -17.68 dB, respectively. The LNA MMIC can withstand 40 dBm (10 W) input power without performance degradation. The chip dimensions are 3.67 mm × 1.15 mm. The developed GaN-based LNA MMIC is applicable to various X-band applications.

• Kyungpook Mathematical Journal
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• v.60 no.1
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• pp.53-69
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• 2020

Let (A, M) ⊂ (B, N) be commutative quasi-local rings. We consider the property that there exists a ring D such that A ⊆ D ⊂ B and the extension D ⊂ B is inert. Examples show that the number of such D may be any non-negative integer or infinite. The existence of such D does not imply M ⊆ N. Suppose henceforth that M ⊆ N. If the field extension A/M ⊆ B/N is algebraic, the existence of such D does not imply that B is integral over A (except when B has Krull dimension 0). If A/M ⊆ B/N is a minimal field extension, there exists a unique such D, necessarily given by D = A + N (but it need not be the case that N = MB). The converse fails, even if M = N and B/M is a finite field.