• Journal of Nutrition and Health
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• v.54 no.5
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• pp.515-533
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• 2021

Purpose: A systematic review and meta-analysis of nutrition educational intervention studies was performed to assess the association between nutrition education intervention and fruit & vegetable (F&V) preferences and nutrition knowledge in preschool children. Methods: The relevant studies of nutrition education intervention and F&V preferences and nutrition knowledge published from January 2000 to June 2020 were located using PubMed, Web of Science, Cochrane Library, Research Information Sharing Service, Korean Studies Information Service System databases, and lists of references. A random-effects meta-analysis was conducted to estimate the standardized mean difference with a 95% confidence interval (CI). Subgroup analyses were performed to identify the association between nutrition education and F&V preferences and nutrition knowledge. Results: The results show that the effect sizes (ES) of F&V preferences and nutrition knowledge of preschool children were 0.31(95% CI, 0.23, 0.39), and 1.69(95% CI, 1.27, 2.12), respectively. The result of subgroup analysis, nutrition education focused on F&V (F&V preferences, ES: 0.32; nutrition knowledge, ES: 2.09) presented a slightly larger effect than general nutrition education (F&V preferences, ES: 0.26; nutrition knowledge, ES: 1.62). As for the type of exposure to F&V, direct exposure education (F&V preferences, ES: 0.40) had a greater effect than indirect exposure (F&V preferences, ES: 0.26). This meta-analysis showed that nutrition education intervention had positive effects on the F&V preferences and nutrition knowledge in preschool children. Conclusion: In conclusion, from the meta-analysis and subsequent subgroup analysis, we found that varied types of nutrition education intervention had varying effects on F&V preferences and nutrition knowledge in preschool children.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.8
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• pp.823-829
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• 2004

In this paper, non-self-aligned SiGe HBTs with ${f}_\tau$ and${f}_max $above 50 GHz have been fabricated using an RPCVD(Reduced Pressure Chemical Vapor Deposition) system for wireless applications. In the proposed structure, in-situ boron doped selective epitaxial growth(BDSEG) and TiSi$_2$ were used for the base electrode to reduce base resistance and in-situ phosphorus doped polysilicon was used for the emitter electrode to reduce emitter resistance. SiGe base profiles and collector design methodology to increase ${f}_\tau$ and${f}_max $ are discussed in detail. Two SiGe HBTs with the collector-emitter breakdown voltages ${BV}_CEO$ of 3 V and 6 V were fabricated using SIC(selective ion-implanted collector) implantation. Fabricated SiGe HBTs have a current gain of 265 ∼ 285 and Early voltage of 102 ∼ 120 V, respectively. For the $1\times{8}_\mu{m}^2$ emitter, a SiGe HBT with ${BV}_CEO$= 6 V shows a cut-off frequency, ${f}_\tau$of 24.3 GHz and a maximum oscillation frequency, ${f}_max $of 47.6 GHz at $I_c$of 3.7 mA and$V_CE$ of 4 V. A SiGe HBT with ${BV}_CEO$ = 3 V shows ${f}_\tau$of 50.8 GHz and ${f}_max $ of 52.2 GHz at $I_c$ of 14.7 mA and $V_CE$ of 2 V.

• Communications of the Korean Mathematical Society
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• v.31 no.3
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• pp.495-505
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• 2016

Let $f:{\mathbb{R}}^3{\rightarrow}{\mathbb{R}}$. In this paper we prove the stability of functional inequalities ${\mid}f(ux+vy,uy-vx,zw)-f(x,y,z)f(u,v,w){\mid}{\leq}{\phi}(u,v,w)$ or ${\phi}(x,y,z)$, ${\mid}f(ux-vy,uy-vx,zw)-f(x,y,z)f(u,v,w){\mid}{\leq}{\phi}(u,v,w)$ or ${\phi}(x,y,z)$ for all $x,y,z,u,v,w{\in}{\mathbb{R}}$. Furthermore, we give refined descriptions of bounded functions satisfying the inequalities as in Albert and Baker [1].

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.189-190
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• 2017

본 논문에서는 PMSM에서 단위 전류당 최대 토크를 발생시키는 MTPA(Maximum Torque Per Ampere)제어에 기반한 센서리스 V/f 운전 기법을 제안한다. 기존의 센서리스 V/f 운전에서는 MTPA 제어가 고려되지 않아 구동 효율이 감소하는데 본 논문에서는 d축 전류를 기반으로 비례적분기 제어기를 사용하여 개선하였다. 또한 부하 변동에 대한 우수한 동특성과 안정성을 갖도록 하였다. 250W 블로워용 PMSM(Permanent Magnet Synchronous Motor)에 대한 실험을 통해 그 효용성을 확인하였다.

• Journal of the Chungcheong Mathematical Society
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• v.21 no.1
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• pp.139-146
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• 2008

We investigate the uniqueness and multiplicity of solutions for the nonlinear elliptic system with Dirichlet boundary condition $$\{-{\Delta}u+g_1(u,v)=f_1(x){\text{ in }}{\Omega},\\-{\Delta}v+g_2(u,v)=f_2(x){\text{ in }}{\Omega},$$ where ${\Omega}$ is a bounded set in $R^n$ with smooth boundary ${\partial}{\Omega}$. Here $g_1$, $g_2$ are nonlinear functions of u, v and $f_1$, $f_2$ are source terms.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.110-112
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• 2006

본 논문에서는 전동기의 경부하진동으로부터 자유로운 새로운 범용인버터를 제안된다. 제안된 범용인버터의 V/f 제어 기법은 벡터방식에 근거하며 전통적인 V/f 제어 기법과는 약간 다른 방식의 제어 기법이다. 제안된 범용인버터의 V/f 제어 기법은 V/f 제어 유도전동기 드라이브 시스템의 안정도를 향상시키기 위하여 다이나믹 전류보상기를 이용한다. 제안된 시스템이 이론적으로 설명되며 그 성능은 실험결과를 통하여 보인다.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.414-415
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• 2018

본 논문에서는 유도 전동기의 V/f 운전 시 동손을 최소로 하는 제어 방법을 제안한다. 제안된 방법은 V/f 운전 시 부하에 따라 최소 동손 제어가 가능하도록 고정자 전압 크기를 가변하여 부하 변동에 따른 동특성 향상과 효율적인 구동이 가능하게 하였다. 5HP 유도 전동기 구동시스템에 대한 시뮬레이션을 통해 제안된 기법의 효용성을 검증하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.742-744
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• 2001

이 논문은 n-차원 스타 그래프 S$_{n}$, n$\geq$4에서 정점과 에지 고장의 수가 n-3 이하일 때, 임의의 두 고장이 아닌 정점 사이에 길이가 두 정점의 색이 같으면 n!-2f$_{v}$ -2 이상이고, 색이 다르면 n!-2f$_{v}$ -1 이상인 경로가 존재함을 보인다. 여기서 f$_{v}$ 는 고장인 정점의 수이다. 이 결과를 이용하면 고장의 수가 n-3이하일 때, 임의의 고장이 아닌 에지를 지나는 길이 n!-2f$_{v}$ 이상인 사이클을 설계할 수 있다.

• Journal of applied mathematics & informatics
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• v.27 no.5_6
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• pp.1157-1163
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• 2009

Let G be a graph with vertex set V(G) and let f be a nonnegative integer-valued function defined on V(G). A spanning subgraph F of G is called a fractional f-factor if $d^h_G$(x)=f(x) for all x $\in$ for all x $\in$ V (G), where $d^h_G$ (x) = ${\Sigma}_{e{\in}E_x}$ h(e) is the fractional degree of x $\in$ V(F) with $E_x$ = {e : e = xy $\in$ E|G|}. In this paper it is proved that if ${\delta}(G){\geq}{\frac{b^2(k-1)}{a}},\;n>\frac{(a+b)(k(a+b)-2)}{a}$ and $|N_G(x_1){\cup}N_G(x_2){\cup}{\cdots}{\cup}N_G(x_k)|{\geq}\frac{bn}{a+b}$ for any independent subset ${x_1,x_2,...,x_k}$ of V(G), then G has a fractional f-factor. Where k $\geq$ 2 be a positive integer not larger than the independence number of G, a and b are integers such that 1 $\leq$ a $\leq$ f(x) $\leq$ b for every x $\in$ V(G). Furthermore, we show that the result is best possible in some sense.

• Journal of applied mathematics & informatics
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• v.35 no.1_2
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• pp.59-74
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• 2017

A radio labeling of a graph G is a function $f:V(G){\rightarrow}\{1,2,{\ldots},k\}$ with the property that ${\mid}f(u)-f(v){\mid}{\geq}1+diam(G)-d(u,v)$ for every pair of vertices $u,v{\in}V(G)$, where diam(G) and d(u, v) are diameter and distance between u and v in the graph G respectively. The radio number of a graph G, denoted by rn(G), is the smallest integer k such that G admits a radio labeling. In this paper, we completely determine radio number of all transformation graphs of a path.