• Communications of the Korean Mathematical Society
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• v.32 no.2
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• pp.361-373
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• 2017

In this paper, we utilize the Nevanlinna theory and uniqueness theory of meromorphic function to investigate the differential-difference analogue of $Br{\ddot{u}}ck$ conjecture. In other words, we consider ${\Delta}_{\eta}f(z)=f(z+{\eta})-f(z)$ and f'(z) share one value or one small function, and then obtain the precise expression of transcendental entire function f(z) under certain conditions, where ${\eta}{\in}{\mathbb{C}}{\backslash}\{0\}$ is a constant such that $f(z+{\eta})-f(z){\not\equiv}0$.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.12 no.2
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• pp.158-160
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• 2001

Ankyloglossia is the presence of a lingual frenulum, which can range from a mucous membrane band to a short and thick band and, in extreme cases, to fusion of the tongue to the floor of the mouth. The effects of such a condition, in addition to speech defects and occasionally restriction of sucking, including dental deformities, such as open bite, or even prognathism. Treatment is surgical. The preferred treatment is horizontal sectioning of the frenulum down to the lingual septum and then suturing of the mucosa. The main problem after the healing of surgical wound is adhesion and contracture. Adhesion restrict the movement of tongue like tongue-tie. Z-plasty at the site of incision can solve this problem by changing the direction of scar. We have experienced a patient with ankyloglossia with speech defect, who underwent frenuloomy by Z-plasty. So we present a surgical treatment of Ankyloglossia using Z-plasty and discuss the treatment with a review of literature.

• The Transactions of the Korea Information Processing Society
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• v.3 no.2
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• pp.407-415
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• 1996

This paper introduces two schemes to improve the frame buffer access bandwidth. The first scheme suggests a rasterizer called SBUFRE that has Span Z Buffer and Span Z＆ Color Buffer within a rasterizer. The second scheme suggests a ZDRAM that has Z-value comparator within the DRAM. These schemes are to convert read- modify-write Z buffer compare into single write only operation that improves approximately 50% frame buffer access bandwidth.

• KSCI Review
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• v.14 no.2
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• pp.141-146
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• 2006

In this paper, we propose a new algorithm for recovering the broken letters of relics into an original form by using Z-map and image processing. The letters of relics may have been broken by a lot of rubbed copy and a long time and tide. They need to be restored. But the manual reconstruction is a very tedious and laborious task. Thus, it is necessary to automate the restoration process. This paper presents a realistic algorithm with an application to Tripitaka Koreana by using Z-map and morphological filter.

• Journal of applied mathematics & informatics
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• v.36 no.5_6
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• pp.567-574
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• 2018

Let $f:f(z)=z+{\sum^{{\infty}}_{n=2}}a_nz^n$ be analytic in the open unit disc E. Then f is said to belong to the class $M_{\alpha}$ of alpha-convex functions, if it satisfies the condition ${\Re}\{(1-{{\alpha})}{\frac{zf^{\prime}(z)}{f(z)}}+{{\alpha}}{\frac{(zf^{\prime}(z))^{\prime})}{f^{\prime}(z)}}\}$ > 0, ($z{\in}E$). In this paper, we introduce and study q-analogue of the class $M_{\alpha}$ by using concepts of Quantum Analysis. It is shown that the functions in this new class $M(q,{\alpha})$ are q-starlike. A problem related to q-Bernardi operator is also investigated.

• Bulletin of the Korean Mathematical Society
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• v.33 no.1
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• pp.1-16
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• 1996

Earlier in 1935[12], M. S. Robertson introduced the class of quadrant preserving functions. More precisely, let Q be the class of all functions f(z) analytic in the unit disk $D = {z : $\mid$z$\mid$ < 1}$ such that f(0) = 0, f'(0) = 1, and the range f(z) is in the j-th quadrant whenever z is in the j-th quadrant of D, j = 1,2,3,4. This class Q contains the subclass of normalized, odd univalent functions which have real coefficients. On the other hand, this class Q is contained in the class T of odd typically real functions which was introduced by W. Rogosinski [13]. Clearly, if $f \in Q$, then f(z) is real when z is real and therefore the coefficients of f are all real. Recently, it was observed by Y. Abu-Muhanna and T. H. MacGregor [1] that any function $f \in Q$ is odd. Instead of functions "preserving quadrants", the authors [1] have introduced the notion of "preserving sectors".

• Korean Journal of Mathematics
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• v.16 no.4
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• pp.481-494
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• 2008

Iteration functions $K_m(z)$ and $U_m(z)$, $m{\geq}2$are defined recursively using the determinant of a matrix. We show that the fixed-iterations of $K_m(z)$ and $U_m(z)$ converge to a simple zero with order of convergence m and give closed form expansions of $K_m(z)$ and $U_m(z)$: To show the convergence, we derive a recursion formula for $L_m$ and then apply the idea of Ford or Pomentale. We also find a Toeplitz matrix whose determinant is $L_m(z)/(f^{\prime})^m$, and then we adapt the well-known results of Gerlach and Kalantari et.al. to give closed form expansions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2161-2166
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• 2008

This paper deals with a Z-source active power filter(Z-AFU) for mitigation voltage THD(total harmonic distortion) due to voltage harmonic propagation(amplification) in 6.6kv power distribution system. Bus voltage harmonic signal is detected by 60Hz butterworth BPF(band pass filter). As an ESS(energy storage system) of the proposed system, PEM fuel cells(Ballard NEXA, 1.2kw) is employed. Test results based on PSIM(power electronics simulation tool) validate the proposed approach.

• Kyungpook Mathematical Journal
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• v.53 no.3
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• pp.459-465
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• 2013

Let $p(z)$ be an analytic function defined on the open unit disk D and $p(0)=1$. Condition ${\beta}$ in terms of complex numbers D and real E with -1 < E < 1 and ${\mid}D{\mid}{\leq}1$ is determined such that $1+{\beta}{\prec}\frac{1+Dz}{1+Ez}$ implies $p(z){\prec}\sqrt{1+z}$. Furthermore, the expression $1+\frac{{\beta}zp^{\prime}(z)}{p(z)}$ and $1+\frac{{\beta}zp^{\prime}(z)}{p^2(z)}$ are considered in obtaining similar results.

• Bulletin of the Korean Mathematical Society
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• v.57 no.6
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• pp.1409-1426
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• 2020

Let 𝒜_n be the class of analytic functions f(z) of the form f(z) = z + ∑^∞_k=n+1 α_kz^k, n ∈ ℕ defined on the open unit disk 𝔻, and let $${\Omega}_n:=\{f{\in}{\mathcal{A}}_n:\|zf^{\prime}(z)-f(z)\|<{\frac{1}{2}},\;z{\in}{\mathbb{D}}\}$$. In this paper, we make use of differential subordination technique to obtain sufficient conditions for the class Ω_n. Writing Ω := Ω₁, we obtain inclusion properties of Ω with respect to functions which map 𝔻 onto certain parabolic regions and as a consequence, establish a relation connecting the parabolic starlike class 𝒮_P and the uniformly starlike UST. Various radius problems for the class Ω are considered and the sharpness of the radii estimates is obtained analytically besides graphical illustrations.