• Bulletin of the Korean Mathematical Society
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• v.55 no.2
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• pp.611-624
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• 2018

In this paper, we study Weierstrass semigroups of ramification points on double covers of plane curves of degree 6. We determine all the Weierstrass semigroups when the genus of the covering curve is greater than 29 and the ramification point is on a total flex.

• Journal of the Korean Mathematical Society
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• v.54 no.1
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• pp.69-86
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• 2017

The point $P{\in}{\mathbb{P}}^2$ is referred to as a Galois point for a nonsingular plane algebraic curve C if the projection ${\pi}_P:C{\rightarrow}{\mathbb{P}}^1$ from P is a Galois covering. In contrast, the point $P^{\prime}{\in}C^{\prime}$ is referred to as a weak Galois Weierstrass point of a nonsingular algebraic curve C' if P' is a Weierstrass point of C' and a total ramification point of some Galois covering $f:C^{\prime}{\rightarrow}{\mathbb{P}}^1$. In this paper, we discuss the following phenomena. For a nonsingular plane curve C with a Galois point P and a double covering ${\varphi}:C{\rightarrow}C^{\prime}$, if there exists a common ramification point of ${\pi}_P$ and ${\varphi}$, then there exists a weak Galois Weierstrass point $P^{\prime}{\in}C^{\prime}$ with its Weierstrass semigroup such that H(P') = or , which is a semigroup generated by two positive integers r and 2r + 1 or 2r - 1, such that P' is a branch point of ${\varphi}$. Conversely, for a weak Galois Weierstrass point $P^{\prime}{\in}C^{\prime}$ with H(P') = or , there exists a nonsingular plane curve C with a Galois point P and a double covering ${\varphi}:C{\rightarrow}C^{\prime}$ such that P' is a branch point of ${\varphi}$.

• The Journal of the Acoustical Society of Korea
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• v.31 no.3
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• pp.161-169
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• 2012

This paper presents a robust speech end-point detector using double talk detection in echoic conditioned speech recognition robot. The proposed method consists of combining conventional end-point detector result and double talk detector result. We have tested the proposed method in isolated word recognition system under echoic conditioned environment. As a result, the proposed algorithm shows superior performance of 30 % to the available techniques in the points of speech recognition rates.

• Advances in concrete construction
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• v.2 no.3
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• pp.229-247
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• 2014

A numerical study of the influence of shear-span/depth ratio on the cohesive crack fracture parameters and double - K fracture parameters of concrete is carried out in this paper. For the study the standard bending specimen geometry loaded with four point bending test is used. For four point loading, the shear - span/depth ratio is varied as 0.4, 1 and 1.75 and the ao/D ratio is varied from 0.2, 0.3 and 0.4 for laboratory specimens having size range from 100 - 500 mm. The input parameters for determining the double - K fracture parameters are taken from the developed fictitious crack model. It is found that the cohesive crack fracture parameters are independent of shear-span/depth ratio. Further, the unstable fracture toughness of double-K fracture model is independent of shear-span/depth ratio whereas, the initial cracking toughness of the material is dependent on the shear-span/depth ratio.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.13 no.2
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• pp.180-187
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• 2002

Background and Objectives : The operation Double Opposing Z-Plasty, has been used for improving VPI function in the submucous cleft palate. However, few reports on the effects of the speech change were presented. The purpose of this study is to compare the difference of nasality and nasalance, parents satisfaction between before and after this operation and to consider how much improvement in speech. Materials and Methods : Ten submucous cleft palate children who underwent double opposing Z-plasty were analyzed. We retrospectively studied nasalance, auditory perception (nasality) with hypernasality, patients satisfaction, speech evaluation by using charts review, video tape, telephone interview. Results : In 8 patients of 10 submucous cleft palate, hypernasality reduced and speech intelligibility was higher and mean 0.35 point was increased in the velum length after operation. After operation, nasality was improved (2.0 point) and level of nasal emission decreased. Regarding satisfaction of this operation, scale was mean 2.8 (5 point-scale) : 8 parents were satisfied in the resonance, 3 parents were satisfied articulation. The reason of dissatisfaction was mostly compensatory articulation. Conclusion : To improve of speech in the submucous cleft palate, speech therapy afterthis operation as well as successful surgery should be considered.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.6
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• pp.1212-1217
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• 2004

The main back-bone operation in elliptic curve cryptosystems is scalar point multiplication. The most frequently used method implementing the scalar point multiplication, which is performed in the upper level of GF multiplication and GF division, has been the double-and-add algorithm, which is recently challenged by NAF(Non-Adjacent Format) algorithm. In this paper, we propose a more efficient and novel scalar multiplication method than existing double-and-add by applying redundant receding which originates from radix-4 Booth's algorithm. After deriving the novel quad-and-add algorithm, we created a new operation, named point quadruple, and verified with real application calculation to utilize it. Derived numerical expressions were verified using both C programs and HDL (Hardware Description Language) in real applications. Proposed method of elliptic curve scalar point multiplication can be utilized in many elliptic curve security applications for handling efficient and fast calculations.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.7
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• pp.63-68
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• 1994

The Curie point annealing effects on electrophysical phenomena at the magnetized strontium ferrite(SrO$\cdot$ 6$Fe_{2}O_{3}$) ceramics electrode/10$^{-3}$M KC1 aqueous electrolyte interfaces have been studied using cyclic voltammetric, normal pulse voltammetric, chronocoulometric, and electrochemical impedance techiques. After the Curie point annealing the magnetic flux densities of the speciment was decreased from 900-1100 gauss to 1-2 gauss, i.e. demagnetized. The real component of interfacial impedance was decreased from 7280-7320 ohm to 790-830 ohm. The adsorption and the charge on the electrical double layer was increased from 0 $\mu$C to -58 $\mu$C. The Curie point annealing and the related electrical double layer effect can influence not only the electrophysical properties of the strontium ferrite ceramics electrode itself but also the electrochemical phenomena at the electrode interface. This experimental results suggest that the Curie point annealing and the related electrical double layer effect can be applied to electrochemical magnetic sensors.

• Journal of the Korea Society of Computer and Information
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• v.6 no.1
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• pp.51-59
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• 2001

In this paper, performance of the double circular array antenna was analyzed, which has sharp directivity with specific direction and is compatible to shape pencil beam. The character of each array geometry which N numbers of isotropic point source is arranged in planar with type of a square, circular and double circular was compared and analyzed. As a result, we fined that double circular geometry was good performance rather than square and circular array geometry in the point of directivity. SLL and HPBW.

• Earthquakes and Structures
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• v.9 no.4
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• pp.767-788
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• 2015

A steel shear wall with double-tapered links and in-plane reference was developed for assisting the assessment of the structural condition of a building after an earthquake while maintaining the original role of the wall as a passive damper device. The double-tapered link subjected to in-plane shear deformation is designed to deform torsionally after the onset of local buckling and works as an indicator of the maximum shear deformation sustained by the shear wall during an earthquake. This paper first examines the effectiveness of double-tapered links in the assessment of the structural condition under various types of loading. A design procedure using a baseline incremental two-cycle loading protocol is verified numerically and experimentally. Meanwhile, in-plane reference links are introduced to double-tapered links and greatly enhance objectivity in the inspection of notable torsional deformation with the naked eye. Finally, a double-layer system, which consists of a layer with double-tapered links and a layer with rectangular links made of low-yield-point steel, is tested to demonstrate the feasibility of realizing both structural condition assessment and enhanced energy dissipation.

• Structural Engineering and Mechanics
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• v.68 no.5
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• pp.633-638
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• 2018

One of the important problems in the vehicle design is vehicle handling and stability. Effective parameters which should be considered in the vehicle handling and stability are roll angle, camber angle and scrub radius. In this paper, a planar vehicle model is considered that two right and left suspensions are double wishbone suspension system. For a better analysis of the suspension geometry, a kinestatic model of vehicle is considered which instantaneous kinematic and statics relations are analyzed simultaneously. In this model, suspension geometry is considered completely. In order to optimum design of double wishbones suspension system, a multi-objective genetic algorithm is applied. Three important parameters of suspension including roll angle, camber angle and scrub radius are taken into account as objective functions. Coordinates of suspension hard points are design variables of optimization which optimum values of them, corresponding to each optimum point, are obtained in the optimization process. Pareto solutions for three objective functions are derived. There are important optimum points in these Pareto solutions which each point represents an optimum status in the model. In other words, corresponding to any optimal point, a specific geometric position is determined for the suspension hard points. Each of the obtained points in the Pareto optimization can be selected for a special design purpose by designer to create an optimum condition in the vehicle handling and stability.