• 대한수학회지
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• 제47권1호
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• pp.101-112
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• 2010

In [3] we showed that a polynomial over a Noetherian ring is divisible by some other polynomial by looking at the matrix formed by the coefficients of the polynomials which we called the resultant matrix. In this paper, we consider the polynomials with coefficients in a field and divisibility of a polynomial by a polynomial with a certain degree is equivalent to the existence of common solution to a system of Diophantine equations. As an application we construct a family of irreducible quartics over $\mathbb{Q}$ which are not of Eisenstein type.

• 대한수학회보
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• 제54권5호
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• pp.1597-1617
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• 2017

The paper is devoted to the description of family of scalene triangles for which the triangle formed by the intersection points of bisectors with opposite sides is isosceles. We call them Sharygin triangles. It turns out that they are parametrized by an open subset of an elliptic curve. Also we prove that there are infinitely many non-similar integer Sharygin triangles.

• 대한수학회보
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• 제53권1호
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• pp.273-301
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• 2016

In this paper, we classify all twisted torus knots which are doubly middle Seifert-fibered. Also we show that all of these knots possibly except a few admit Dehn surgery producing a non-Seifert-fibered graph manifold which consists of two Seifert-fibered spaces over the disk with two exceptional fibers, glued together along their boundaries. This provides another infinite family of knots in $S^3$ admitting Dehn surgery yielding such manifolds as done in [5].

• Korean Journal of Mathematics
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• 제12권1호
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• pp.33-40
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• 2004

Let $E,F{\subset}(R^*)^n$ be non-empty sets and let ${\Gamma}$ be this family of all closed curves which join E to F in $(R^*)^n$. In this paper, we shall study the problems of finding properties for the conductance $C({\Gamma})$. And we obtain the inequalities in connection with capacity of condensers.

• 한국포장학회지
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• 제19권1호
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• pp.51-56
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• 2013

본 실험에서는 청과물의 포장 완충재로 사용되고 있는 골판지의 압축 및 충격특성을 이용하여 완충곡선(peak acceleration - static stress curve)을 구현하기 위한 알고리즘을 제시하였다. 본 연구에서 알 수 있듯이 한 개의 동적계수로도 완충곡선을 구현할 수 있음을 알 수가 있었으며, 기존의 완충곡선의 구현시 정적응력 범위 내에서의 실험횟수를 현저하게 줄일 수 있음을 알 수가 있었다. 또한, 골판지 완충재료 외에 플라스틱 발포체 완충재료에도 적용이 가능할 것으로 판단되었다.

• 대한수학회논문집
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• 제9권4호
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• pp.905-915
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• 1994

Let $M_g$ be the moduli space of isomorphism classes of genus g smooth curves. It is a quasi-projective variety of dimension 3g - 3, when $g > 2$. It is known that a complete subvariety of $M_g$ has dimension $< g-1 [D]$. In general it is not known whether this bound is rigid. For example, it is not known whether $M_4$ has a complete surface in it. But one knows that there is a complete curve through any given finite points [H]. Recently, an explicit example of a complete curve in moduli space is given in [G-H]. In [G-H] they constructed a complete curve of $M_3$ as an intersection of five hypersurfaces of the Satake compactification of $M_3$. One way to get a complete curve of $M_3$ is to find a complete one dimensional family $p : X \to B$ of plane quartics which gives a nontrivial morphism from the base space B to the moduli space $M_3$. This is because every non-hyperelliptic smooth curve of genus three can be realized as a nonsingular plane quartic and vice versa. This paper has come out from the effort to find such a complete family of plane quartics. Since nonsingular quartics form an affine space some fibers of p must be singular ones. In this paper, due to the semistable reduction theorem [M], we search singular plane quartics which can occur as singular fibers of the family above. We first list all distinct plane quartics in terms of singularities.

• Asian Pacific Journal of Cancer Prevention
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• 제13권11호
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• pp.5483-5488
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• 2012

Background: Although nicotine dependence plays a role as a main barrier for smoking cessation, there is still a lack of solid evidence on the validity of biomarkers to determine nicotine dependence in clinical settings. This study aimed to investigate whether urinary cotinine levels could reflect the severity of nicotine dependence in active smokers. Materials and Methods: Data regarding general characteristics and smoking status was collected using a self-administered smoking questionnaire. The Fagerstr$\ddot{o}$m test for nicotine dependence (FTND) was used to determine nicotine dependence of the participants, and a total of 381 participants were classified into 3 groups of nicotine dependence: low (n=205, 53.8%), moderate (n=127, 33.3%), and high dependence groups (n=49, 12.9%). Stepwise multiple linear regression model and receiver operating characteristic (ROC) curves analyses were used to determine the validity of urinary cotinine for high nicotine dependence. Results: In correlation analysis, urinary cotinine levels increased with FTND score (r=0.567, P<0.001). ROC curves analysis showed that urinary cotinine levels predicted the high-dependence group with reasonable accuracy (optimal cut-off value=1,000 ng/mL; AUC=0.82; P<0.001; sensitivity=71.4%; specificity=74.4%). In stepwise multiple regression analysis, the total smoking period (${\beta}$=0.042, P=0.001) and urinary cotinine levels (${\beta}$=0.234, P<0.001) were positively associated with nicotine dependence, whereas an inverse association was observed between highest education levels (>16 years) and nicotine dependence (${\beta}$=-0.573, P=0.034). Conclusions: The results of this study support the validity of using urinary cotinine levels for assessment of nicotine dependence in active smokers.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7117-7120
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• 2013

Background: This study hypothesized living in a poor neighborhood decreased the cause specific survival in individuals suffering from carcinoid carcinomas. Surveillance, Epidemiology and End Results (SEER) carcinoid carcinoma data were used to identify potential socioeconomic disparities in outcome. Materials and Methods: This study analyzed socioeconomic, staging and treatment factors available in the SEER database for carcinoid carcinomas. The Kaplan-Meier method was used to analyze time to events and the Kolmogorov-Smirnov test to compare survival curves. The Cox proportional hazard method was employed for multivariate analysis. Areas under the receiver operating characteristic curves (ROCs) were computed to screen the predictors for further analysis. Results: There were 38,546 patients diagnosed from 1973 to 2009 included in this study. The mean follow up time (S.D.) was 68.1 (70.7) months. SEER stage was the most predictive factor of outcome (ROC area of 0.79). 16.4% of patients were un-staged. Race/ethnicity, rural urban residence and county level family income were significant predictors of cause specific survival on multivariate analysis, these accounting for about 5% of the difference in actuarial cause specific survival at 20 years of follow up. Conclusions: This study found poorer cause specific survival of carcinoid carcinomas of individuals living in poor and rural neighborhoods.

• 정보보호학회논문지
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• 제11권6호
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• pp.105-113
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• 2001

최근에 Gallant, Lambert, Vanstone은 소수체 위에 정의된 타원곡선이 효율적으로 계산 가능한 자기준동형을 가질 때 스칼라 곱을 가속화하는 방법을 제안하였다. 이 방법은 실제로 자기준동형의 특성다항식의 고유치를 사용하여 스칼라를 분해하는데 기반을 두고 있다. 본 논문에서는 그러한 타원곡선의 자기준동형 환의 원소를 이용하여 스칼라를 분해하는 개선된 알고리즘을 제안한다. 이 알고리즘은 Gallant 등의 알고리즘보다 속도면에서 효율적이며 분해성분들의 구체적인 상한 값을 줄 수 있다.

• 한국지반공학회지:지반
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• 제12권6호
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• pp.5-20
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• 1996

본 논문은 말뚝의 선단과 두부조건이 자유이며 수평하중을 받고 있는 수직말뚝의 모형실험에 대한 결과를 보여주고 있다. 모형실험은 원심모형실험기(동경공업대학 Markll)를 이용하여 현장응력상태하의 사질토지반에서 실시되었으며, 중력가속도, 휭강성, 그리고 지반의 상대밀도를 달리하여 실험을 실시하였다. 본 연구의 목적은 Toyoura모래에 근입된 말뚝의 거동에 대해 중력가속도, 횡강성, 그리고 상대밀도의 영향과 여러학자(Murchison & O'Neill, Reese et at., Scott, Det Norske Vertas, Kondner)들에 의해 제안된 p-y곡선의 적용성 검토에 있다. p-V곡선에 의해 프로그램이 만들어졌으며, 이 프로그램으로 말뚝의 수평변위와 모멘트 그리고 지반반력 분포를 예측할 수 있다. 실측된 거동과 예측된 거동의 비교에서, Murchison & O'Neill과 Kondnor에 의해 제안된 p-y곡선식의 결과가 다른 식들보다 실측결과와 일치하였다.