• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.206-213
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• 2013

본 논문에서는 적분변환법을 이용하여 면외전단 충격하중이 작용하는 두 개의 서로 다른 압전재료층 사이의 기능경사압전재료 접합층 내부 균열에 대한 과도응답 해석 을 수행한다. 기능경사압전재료의 물성치는 두께 방향을 따라 연속적으로 변하는 것으로 가정한다. 라플라스 변환과 푸리에 변환을 이용하여 문제를 복합적분방정식으로 구성하고, 수치해석을 위해 복합적 분방정식을 제 2 종 프레드홀름 적분방정식으로 표현한다. 전기적 하중, 재료물성 치의 변화율, 각 접합층의 두께가 균열의 과도응답에 미치는 영향을 보기 위해 동에너지 해방률에 대한 수치해석 결과를 제시한다.

• 대한기계학회논문집
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• 제17권9호
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• pp.2172-2180
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• 1993

Under general loadings, including body forces, crack-face tractions and thermal loading, the energy release rate equation for a two-dimensional cracked body is presented. Defining the virtual crack extension as the variation of the geometry, the equation is directly derived by a shape design sensitivity of the potential energy. Although the form of the derived energy release rate equation is different from other researchers's results, the three example show that the former is exactly the same as the latter. However, the final integral equation do not involve the derivative of the displacement on the crack surface and crack tip region, thereby improving the numerical accuracy in the computation of the energy relase rate. Moreover, as it was derived from the governing equation including non-linear elasticity without special assumptions, the energy release rate of a elasto-plastic fracture can be obtained and any numerical stress analysis method can be applied.

• 대한수학회논문집
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• 제33권2호
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• pp.549-560
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• 2018

Since Mittag-Leffler introduced the so-called Mittag-Leffler function in 1903, due to its usefulness and diverse applications, a variety and large number of its extensions (and generalizations) and variants have been presented and investigated. In this sequel, we aim to introduce a new extension of the Mittag-Leffler function by using a known extended beta function. Then we investigate ceratin useful properties and formulas associated with the extended Mittag-Leffler function such as integral representation, Mellin transform, recurrence relation, and derivative formulas. We also introduce an extended Riemann-Liouville fractional derivative to present a fractional derivative formula for a known extended Mittag-Leffler function, the result of which is expressed in terms of the new extended Mittag-Leffler functions.

• Asian Pacific Journal of Cancer Prevention
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• 제16권10호
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• pp.4211-4214
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• 2015

Background: Prognostic value of prophylactic level VII nodal dissection in papillary thyroid carcinoma has been highlighted. Materials and Methods: A total of 27 patients with papillary thyroid carcinoma with N0 neck underwent total thyroidectomy with level VI and VII nodal dissection through same collar neck incision. Multicentricity, bilaterality, extrathyroidal extension, level VI and VII lymph nodes were studied as separate and independent prognostic factors for DFS at 24 months. Results: 21 females and 6 males with a mean age of 34.6 years old, tumor size was 5-24 mm. (mean 12.4 mm.), multicentricity in 11 patients 2-4 foci (mean 2.7), bilaterality in 8 patients and extrathyroidal extension in 8 patients. Dissected level VI LNs 2-8 (mean 5 LNs) and level VII LNs 1-4 (mean 1.9). Metastatic level VI LNs 0-3 (mean 1) and level VII LNs 0-2 (mean 0.5). Follow-up from 6-51 months (mean 25.6) with 7 patients showed recurrence (3 local and 4 distant). Cumulative DFS at 24 months was 87.8% and was significantly affected in relation to bilaterality (p-value <0.001), extrathyroidal extension (p-value <0.001), level VI positive ((p-value <0.001) and level VII positive ((p-value <0.001) LNs. No recurrences were detected during the follow-up period in the absence of level VI and level VII nodal involvement. Conclusions: Level VII prophylactic nodal dissection is an important and integral prognostic factor in papillary thyroid carcinoma. A larger multicenter study is crucial to reach a satisfactory conclusion about the necessity and safety of this approach.

• International Journal of Control, Automation, and Systems
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• 제4권6호
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• pp.775-781
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• 2006

An intelligent optimization method for designing Fractional Order PID(FOPID) controllers based on Particle Swarm Optimization(PSO) is presented in this paper. Fractional calculus can provide novel and higher performance extension for FOPID controllers. However, the difficulties of designing FOPID controllers increase, because FOPID controllers append derivative order and integral order in comparison with traditional PID controllers. To design the parameters of FOPID controllers, the enhanced PSO algorithms is adopted, which guarantee the particle position inside the defined search spaces with momentum factor. The optimization performance target is the weighted combination of ITAE and control input. The numerical realization of FOPID controllers uses the methods of Tustin operator and continued fraction expansion. Experimental results show the proposed design method can design effectively the parameters of FOPID controllers.

• Kyungpook Mathematical Journal
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• 제56권4호
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• pp.1115-1123
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• 2016

Let $D{\subseteq}E$ be an extension of integral domains with characteristic zero, I be a nonzero proper ideal of D and let H(D, E) and H(D, I) (resp., h(D, E) and h(D, I)) be composite Hurwitz series rings (resp., composite Hurwitz polynomial rings). In this paper, we show that H(D, E) satisfies the ascending chain condition on principal ideals if and only if h(D, E) satisfies the ascending chain condition on principal ideals, if and only if ${\bigcap}_{n{\geq}1}a_1{\cdots}a_nE=(0)$ for each infinite sequence $(a_n)_{n{\geq}1}$ consisting of nonzero nonunits of We also prove that H(D, I) satisfies the ascending chain condition on principal ideals if and only if h(D, I) satisfies the ascending chain condition on principal ideals, if and only if D satisfies the ascending chain condition on principal ideals.

• 대한수학회지
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• 제42권2호
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• pp.203-222
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• 2005

Thompson series is a Hauptmodul for a genus zero group which lies between $\Gamma$o(N) and its normalizer in PSL2(R) ([1]). We construct explicit ring class fields over an imaginary quadratic field K from the Thompson series $T_g$($\alpha$) (Theorem 4), which would be an extension of [3], Theorem 3.7.5 (2) by using the Shimura theory and the standard results of complex multiplication. Also we construct various class fields over K, over a CM-field K (${\zeta}N + {\zeta}_N^{-1}$), and over a field K (${\zeta}N$). Furthermore, we find an explicit formula for the conjugates of Tg ($\alpha$) to calculate its minimal polynomial where $\alpha$ (${\in}{\eta}$) is the quotient of a basis of an integral ideal in K.

• 대한수학회논문집
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• 제27권3호
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• pp.547-556
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• 2012

A new Hardy-Hilbert type integral inequality for double series with weights can be established by introducing a parameter ${\lambda}$ (with ${\lambda}>1-\frac{2}{pq}$) and a weight function of the form $x^{1-\frac{2}{r}}$ (with $r$ > 1). And the constant factors of new inequalities established are proved to be the best possible. In particular, for case $r$ = 2, a new Hilbert type inequality is obtained. As applications, an equivalent form is considered.

• East Asian mathematical journal
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• 제33권3호
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• pp.317-322
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• 2017

Let $D{\subseteq}E$ be an extension of integral domains with characteristic zero, I be a nonzero proper ideal of D, and let H(D, E) and H(D, I) (resp., h(D, E) and h(D, I)) be composite Hurwitz series rings (resp., composite Hurwitz polynomial rings). In this article, we show that H(D, E) is an Archimedean ring if and only if h(D, E) is an Archimedean ring, if and only if ${\bigcap}_{n{\geq}1}d^nE=(0)$ for each nonzero nonunit d in D. We also prove that H(D, I) is an Archimedean ring if and only if h(D, I) is an Archimedean ring, if and only if D is an Archimedean ring.

• 대한수학회논문집
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• 제35권4호
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• pp.1123-1132
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• 2020

In the present paper, we define new class of functions T_α,β(λ; z) which is an extension of the classical Wright function and the Mittag-Leffler function. We show some mean value inequalities for the this function, such as Turán-type inequalities, Lazarević-type inequalities and Wilker-type inequalities. Moreover, integrals formula and integral inequality for the function T_α,β(λ; z) are presented.