• Bulletin of the Korean Mathematical Society
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• v.58 no.3
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• pp.617-635
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• 2021

Let X be a smooth hypersurface X of degree d ≥ 4 in a projective space ℙⁿ⁺¹. We consider a projection of X from p ∈ ℙⁿ⁺¹ to a plane H ≅ ℙⁿ. This projection induces an extension of function fields ℂ(X)/ℂ(ℙⁿ). The point p is called a Galois point if the extension is Galois. In this paper, we will give necessary and sufficient conditions for X to have Galois points by using linear automorphisms.

• The Pure and Applied Mathematics
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• v.28 no.4
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• pp.399-411
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• 2021

We consider a Weierstrass semigroup at a generalized flex on a smooth plane curve. We find the candidates of a Weierstrass semigroup at a 2-flex of higher multiplicity on a smooth plane curve of degree d ≥ 5, and give some examples to show the existence of them.

• Journal of the Korean Mathematical Society
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• v.60 no.5
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• pp.987-998
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• 2023

It is shown that every continuum-wise expansive C¹ generic vector field X on a compact connected smooth manifold M satisfies Axiom A and has no cycles, and every continuum-wise expansive homoclinic class of a C¹ generic vector field X on a compact connected smooth manifold M is hyperbolic. Moreover, every continuum-wise expansive C¹ generic divergence-free vector field X on a compact connected smooth manifold M is Anosov.

• International Journal of Concrete Structures and Materials
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• v.6 no.2
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• pp.101-110
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• 2012

This paper focuses on the finite element (FE) response sensitivity and reliability analyses considering smooth constitutive material models. A reinforced concrete frame is modeled for FE sensitivity analysis followed by direct differentiation method under both static and dynamic load cases. Later, the reliability analysis is performed to predict the seismic behavior of the frame. Displacement sensitivity discontinuities are observed along the pseudo-time axis using non-smooth concrete and reinforcing steel model under quasi-static loading. However, the smooth materials show continuity in response sensitivity at elastic to plastic transition points. The normalized sensitivity results are also used to measure the relative importance of the material parameters on the structural responses. In FE reliability analysis, the influence of smoothness behavior of reinforcing steel is carefully noticed. More efficient and reasonable reliability estimation can be achieved by using smooth material model compare with bilinear material constitutive model.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.2
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• pp.97-101
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• 2013

Bit-depth expansion is a process of enhancing the image quality by increasing the number of intensity levels. To solve this problem, a hybrid method is proposed, where the pixels are categorized into smooth and complex regions, and are processed using different methods. The pixels in the smooth region are reconstructed with a smooth prior, and a Bayesian estimator is used for the pixels in the complex region. The proposed method effectively removes the false contour artifacts while requiring less computation than conventional methods. In addition, the method shows good quantitative performance, and the PSNR gains over the best existing method are 1.45 dB and 0.26 dB for 4 bits and 3 bits expansion cases, respectively.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1818-1823
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• 2007

In this paper, notched bar tensile tests of Inconel 617 were performed at room ($20^{\circ}C$) and elevated ($800^{\circ}C$) temperature. Finite element analyses are also performed. It is found that, at the room temperature, smooth bar tensile test results could be used to simulate notched bar tensile tests. However, at the elevated temperature, notched bar tensile test results can not be simulated from smooth bar tensile test results. Metallurgical examination reveals that strength weakening results from many cavities over the specimens for smooth bar test at the elevated temperature. "True" tensile properties at the elevated temperature is found using FE simulations. It also suggests that cautious should be taken to determine tensile properties of Inconel 617 at elevated temperatures using smooth bar tests.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.564-568
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• 2006

Smooth picture module is operated by vibration to tilt the light from the DMD (digital micro mirror device) of DLP projection TV, which makes the screen of the TV smoother and DMD chip cost lower. To satisfy the vibration characteristics of smooth picture module, it is designed by optimizing moment of inertia, spring constant and damping coefficient, using structural and fluid dynamic simulation that showed a good agreement with experimental data. To reduce the material cost and moment of inertia, engineering plastic is used and the reliability is estimated. A VCM (voice coil motor) type actuator for smooth picture has to satisfy performance requirements such as higher driving force, lower power consumption, and lower cost. The initial design and optimization for VCM was performed using FE analysis. It allowed us to optimize the design of magnetic circuit of the proposed actuator to obtain higher force while maintaining a lower cost.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.57-60
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• 2009

본 논문에서는 DSDV 프로토콜을 사용하여 MN의 이동으로 포워딩이 실패하면 smooth handoff방식을 사용하지 않고 바로 애드 혹 라우팅 기법을 통해 이동 노드를 통해 데이터그램을 전달하도록 하는 실험을 수행하였는데, DSDV 라우팅 프로토콜을 사용한 방식의 경우 핸드오프가 발생하지 않은 경우와 거의 같은 성능을 나타냈으며, MN의 개수에 따라서는 전송지연시간이 증가하나 핸드오프 발생간격에는 거의 무관하며 기존의 방식들에 비해 전송지연시간이 작아짐을 확인할 수 있다. 중계 노드의 이동은 DSDV 라우팅 방식의 가장 큰 문제점이지만 중계 노드의 이동속도가 실제로는 5m/sec이내가 대부분이므로 크게 문제되지는 않는다. 이와 같은 연구 결과를 캠퍼스와 같이 제한된 지역에서 활용할 경우 smooth handoff의 속도 지연에 대한 문제를 줄일 수 있을 것으로 예상된다.

• Journal of IKEEE
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• v.13 no.3
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• pp.32-38
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• 2009

Ultrasonic motor (USM) is a new type motor which is driven by the ultrasonic vibration of piezoelectric elements. It possess many useful features that electromagnetic motors do not have, such as low speed and high torque. However, ultrasonic motor has heavy nonlinear speed characteristics and is sensitive to the change of drive conditions. In order to solve these problems, we present a smooth position control scheme for ultrasonic motor using fuzzy logic control with human expertise and without the need of any precise mathematical model. A "smooth operation" consideration is included when constructing the fuzzy rule base in order to achieve a most smooth response. An experimental position control system is constructed to show the effectiveness of the proposed control scheme.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.1
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• pp.1-9
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• 2010

The actual hysteretic behavior of structural elements and systems is closer to smooth hysteretic behavior than piece-wise linear behavior. This paper presents a methodology for computing the constant-ductility inelastic response spectra for smooth hysteretic behaviors. The effect of the hysteretic smoothness on the inelastic response spectra for acceleration, displacement, and input energy is evaluated. The results indicate that increasing smoothness in the hysteretic behavior decreases the inelastic response spectra.