• Communications of the Korean Mathematical Society
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• v.9 no.4
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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.

• Journal of Korean Port Research
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• v.12 no.1
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• pp.131-143
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• 1998

This paper presents derivation of stage-discharge curve for Yangsan river. To derivate of stage-discharge lationship is one of the essential research areas in the water resource field. It provides reliable data a long term planning and hydrologic quantity on water resource development by quantitative analysis. The rating curve derivated through 15 discharge-observation on Yangsan river basin in 1997 has been estimated Q=1283.0262-1553.3158H+477.2702H2. According to the rating curve, the highest water level 2.6m, the limited water-level should be bound to the maximum of 2.6m. Before this research, stage-discharge curve of Yangsan river has not been developed, and only 15 discharge observation(hydrometry) has been carried out though this research. Therefore it seems necessary to collect observation data through a long term process to obtain a reliable rating curve equation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.1039-1040
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• 2010

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.12
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• pp.5037-5041
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• 2015

Background: An hCG regression curve has been used to predict the natural history and response to chemotherapy in gestational trophoblastic disease. We constructed hCG regression curves in high-risk gestational trophoblastic neoplasia (GTN) treated with EMA/CO and identified an optimal hCG level to detect EMA/CO resistance in GTN. Materials and Methods: Eighty-one women with GTN treated with EMA/CO were classified as primary high-risk GTN (n = 65) and single agent-resistance GTN (n = 16). The hCG levels prior to each course of chemotherapy were plotted in the 10th, 50th, and 90th percentiles to construct the hCG regression curves. Diagnostic performance was evaluated for an optimal cut-off value. Results: The median hCG levels were 264,482 mIU/mL mIU/mL and 495.5 mIU/mL mIU/mL for primary high-risk GTN and single agent-resistance GTN, respectively. The 50th percentile of the hCG level in primary high-risk GTN and single agent-resistance turned to normal before the 4th and the 2nd course of chemotherapy, respectively. The 90th percentile of the hCG level in primary high-risk GTN and single agent-resistance turned to normal before the 9th and the 2nd course of chemotherapy, respectively. The hCG level of ${\geq}118.6mIU/mL$ mIU/mL at the 5thcourse of EMA/CO predicted the EMA/CO resistance in primary high-risk GTN patients with a sensitivity of 85.7% and a specificity of 100%. Conclusion: EMA/CO resistance in primary high-risk GTN can be predicted by using an hCG regression curve in combination with the cut-off value of 118.6 mIU/mL at the 5thcourse of chemotherapy.

• Korean Journal of Computational Design and Engineering
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• v.11 no.4
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• pp.246-255
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• 2006

Ribs and fans are interesting geometric entities that are derived from an ordinary $B\'{e}zier$ curve or surface. A rib itself is a $B\'{e}zier$ curve or surface with a lower degree than the given curve or surface. A fan is a vector field whose degree is also lower than its origin. First, we present methods to transform the control points of a $B\'{e}zier$ curve or surface into the control points and vectors of its ribs and fans. Then, we show that a $B\'{e}zier$ curve of degree n is decomposed into a rib of degree (n-1), a fan of degree (n-2), and a scalar function of degree 2. We also show that a $B\'{e}zier$ surface of degree (m, n) is decomposed into a rib of degree (m-1, n-1) and three fans of degrees (m-1, n-2), (m-2, n-1), and (m-2, n-2), respectively. In addition, the lengths of the fans are further controlled by scalar functions of degree 2 and (2, 2). We present relevant notations and definitions, introduce theories, and present some of design examples.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.61-63
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• 1998

A B-H curve measuring system for testing softmagnetic materials was constructed. This system can measure the B-H curve in the low frequency(0.1 - 1 Hz) range. The drift of the integrator can be moderately removed by software technique. The advantages of the developed system are easier to measure B-H curve compared with conventional measuring system and low cost.

• Journal of the Korean Magnetics Society
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• v.5 no.3
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• pp.216-221
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• 1995

Both manufacturing parameters and particles' chemical composition controll coercivity and its distribution of magnetic particles. The coercivity and its distribution are important properties for high density magnetic recording, so these are used as tool for evaluation of reproducibility of magnetic particles. We report in this paper the applications of dM/dH versus H curve, which is derived from magnetic hysteresis loop, to the evaluation of coercivity distribution of magnetic particles and oxidation studies of recording metal particles. The coercivity distri-bution can be estimated from the full width half rnaximun (FWHM) and the peak shape of the dM/dH versus H curve. The peak shape of the curve depends upon distribution of particles' coercivity. The peak of dM/dH versus H curve becomes broad and lor is splitted into two or rmre peaks. It depends on uniformity of particles' coercivity. When the coercivity difference between Ba-Ferrite and ${\gamma}-Fe_{2}O_{3}$ is larger than 600 Oe, the peak becomes broad and is consequently splitted into two peaks. Ununiformly substituted Ba-Ferrite particles show broad peak. It is apparent that the analysis of the curve is one of sensitive measuring techniques for determination of coercivity distri-bution and studies on magnetic properties of substituted Ba-Ferrite and oxidation of magnetic recording metal particles.

• Bulletin of the Korean Mathematical Society
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• v.46 no.1
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• pp.99-105
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• 2009

Let $M=H_1{\cup}_SH_2$ be a Heegaard splitting of a 3-manifold M, D be an essential disk in $H_1$ and A be an essential annulus in $H_2$. Suppose D and A intersect in one point. First, we show that a Heegaard splitting admitting such a (D, A) pair satisfies the disjoint curve property, yet there are infinitely many examples of strongly irreducible Heegaard splittings with such (D, A) pairs. In the second half, we obtain another Heegaard splitting $M=H'_1{\cup}_{S'}H'_2$ by removing the neighborhood of A from $H_2$ and attaching it to $H_1$, and show that $M=H'_1{\cup}_{S'}H'_2$ also has a (D, A) pair with $|D{\cap}A|=1$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.305-306
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• 2013

• YAKHAK HOEJI
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• v.39 no.6
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• pp.645-653
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• 1995

Dibenamine inhibited [$^{3}$H]quinuclidinyl benzilate ([$^{3}$H]QNB) binding in both concentration and incubation time-dependent manners. The $IC_{50}$/ value of dibenamine for the inhibition of the specific binding of 100 pM [$^{3}$'H]QNB following incubation of cerebral microsomes with dibenamine at 37.deg. C for 15 min was 20.mu.M. Dibenamine irreversibly decreased the binding site concentration for [$^{3}$H]QNB binding without affecting the affinity of [$^{3}$H]QNB for the muscarinic receptor. Analysis of the pirenzepine inhibition curve of [$^{3}$H]QNB binding to cerebral microsomes indicated the presence of two receptor subtypes with high(M$_{1}$ receptor, Ki=5nM) and low (M$_{2}$ receptor, Ki=160nM) affinity for pirenzepine. However, dibenamine(20.mu.M) treatment under the condition employed in these experiments caused steepening of the pirenzepine competition curve. The Ki value for pirenzepine in dibenamine treated-microsomes was approximately 120nM. suggesting a selective decrease in the number of M$_{1}$ receptor. Although dibenamine also inhibited [$^{3}$H]QNB binding to ventricular microsomes with $IC_{50}$/ value of 120.mu.M, the sensitivity for dibenamine in the ventricle was much lower than that in the cerebrum. These results indicate that dibenamine at low concentrations welectively inactivates the muscarinic M$_{1}$ receptor.