• Bulletin of the Korean Mathematical Society
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• v.53 no.6
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• pp.1707-1714
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• 2016

Let $C{\subset}{\mathbb{P}}^r$ be a nondegenerate projective curve of degree d > r + 1 and of maximal regularity. Such curves are always contained in the threefold scroll S(0, 0, r - 2). Also some of such curves are even contained in a rational normal surface scroll. In this paper we study the minimal free resolution of the homogeneous coordinate ring of C in the case where $d{\leq}2r-2$ and C is contained in a rational normal surface scroll. Our main result provides all the graded Betti numbers of C explicitly.

• Journal of Korean Academy of Nursing
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• v.41 no.6
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• pp.758-767
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• 2011

Purpose: This study was done to examine the threshold value of estimated height loss at which the risk of osteoporosis increases and to verify its discriminative ability in the detection of osteoporosis. Methods: It was conducted based on epidemiological descriptive methods on 732 Korean women at a public healthcare center in Seoul between July and November 2010. ANOVA, Pearson correlation, logistic regression analysis and receiver operating characteristics (ROC) curve were used for data analysis. Results: There was an age-related correlation between bone mineral density (lumbar spine: F=37.88, p<.001; femur: F=54.27, p<.001) and estimated height loss (F=27.68, p<.001). Estimated height loss increased significantly with decreasing bone mineral density (lumbar spine: r=-.23, p<.001; femur: r=-.34, p<.001). The odds ratio for the point at which the estimated height loss affects the occurrence of osteoporosis was found to increase at a cut-off value of 2 cm and the area under ROC curve was .71 and .82 in lumbar spine and femur, respectively. Conclusion: The optimal cut-off value of the estimated height loss for detection of osteoporosis was 2 cm. Height loss is therefore a useful indicator for the self-assessment and prognosis of osteoporosis.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.293-297
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• 2013

Background: : Chemotherapy-induced thrombocytopenia (CIT) is an important cause of morbitity in patients with cancer. Aim: To investigate the effect of the baseline plasma D-dimer level, an important marker for thrombotic activity, on chemotherapy-induced thrombocytopenia in patients with stage III colon cancer. Materials and Methods: A total of 43 (28 men) eligible patients were divided into two groups according to whether they exhibited chemotherapy-induced thrombocytopenia: Group 1 (n=21) and Group 2 (n=22). Comparison was made using demographic, histopathologic, and laboratory variables. Additionally, baseline plasma D-dimer levels underwent receiver operation characteristics curve analysis, and areas under the curve were calculated. Sensitivity, specificity, and positive and negative likelihood rates were then determined. Results: The incidence of chemotherapy-induced thrombocytopenia had a significant correlation with baseline platelet count (r=0.568, P=0.031) and baseline plasma D-dimer levels (r=0.617, P=0.036). When the cut-off point for the latter was set as 498 ng/mL, the area under the curve was 0.89 (95%CI: 0.74-0.93), the sensitivity was 91.4%, the specificity was 89.7%, the positive likelihood rate was 3.64 and the negative likelihood rate was 0.24 for chemotherapy-induced thrombocytopenia diagnosis. Conclusions: The baseline level of plasma D-dimer could help to differentiate high-risk patients for chemotherapy-induced thrombocytopenia.

• Kyungpook Mathematical Journal
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• v.56 no.2
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• pp.583-595
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• 2016

Archimedes showed that for a point P on a parabola X and a chord AB of X parallel to the tangent of X at P, the area S of the region bounded by the parabola X and chord AB is four thirds of the area T of triangle ${\Delta}ABP$. It is well known that the area U formed by three tangents to a parabola is half of the area T of the triangle formed by joining their points of contact. Recently, the first and third authors of the present paper and others proved that among strictly locally convex curves in the plane ${\mathbb{R}}^2$, these two properties are characteristic ones of parabolas. In this article, in order to generalize the above mentioned property $S={\frac{4}{3}}T$ for parabolas we study strictly locally convex curves in the plane ${\mathbb{R}}^2$ satisfying $S={\lambda}T+{\nu}U$, where ${\lambda}$ and ${\nu}$ are some functions on the curves. As a result, we present two conditions which are necessary and sufficient for a strictly locally convex curve in the plane to be an open arc of a parabola.

• Journal of the korean academy of Pediatric Dentistry
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• v.42 no.1
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• pp.30-37
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• 2015

A new colorimetric test ($Cariview^{(R)}$) using a new type of pH indicator can reflect the acidogenic potential of plaque bacteria. The objective of this study was to evaluate the correlation between $Cariview^{(R)}$ and the caries experience (measured through the dmft index) of children, and to compare $Cariview^{(R)}$ with Dentocult $SM^{(R)}$. Having obtained informed consent, 135 children less than 6 years old participated in the study. We examined their dmft index, and performed two caries activity tests ($Cariview^{(R)}$ and Dentocult $SM^{(R)}$) according to the manufacturers' instructions. In the results, $Cariview^{(R)}$ showed a moderate correlation with the dmft index (r = 0.43, p < 0.01). $Cariview^{(R)}$ showed a sensitivity of 68.8%, a specificity of 69.2%, and an area under curve of 0.686 in the ROC curve analysis. $Cariview^{(R)}$ had a significant correlation with the children's caries experience and had a slightly better explanatory ability than Dentocult $SM^{(R)}$. Furthermore, $Cariview^{(R)}$ was convenient and easy to use on uncooperative children, and also had an educational effect with its visual colors. It is suggested that $Cariview^{(R)}$ could be used clinically to identify the children susceptible to develop caries and to establish a preventive strategy.

• Korean Journal of Optics and Photonics
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• v.1 no.2
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• pp.155-161
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• 1990

A Continous wave tunable $CO_2$ laser which is the slow axial flow type was construccted for the optical pumping of methyl alcohol ($CH_3OH$) laser. The reflective grating of 100 grooveslmm and 10.6$\mu\textrm{m}$ blaze wavelength was used to select wavelength. We have investigated continous outpu: power characteristics, and then have compared tuned output power profile with the gain curve of $CO_2$ laser. The optimum condition for maxium power was found at the gas mixing ratio 1 : 3 : 10 for $CO_2: N_2$ and He. under this condition the flow rate, pressure of lasing gas and discharge current are 9.5 llmin. 14 torr, and 55 mA respectively. The maxium output power was 55 Wlm. Output power of single wavelength operation was measured on 60 individual rotation vibration transitions in the P and K branches of the 9.5$\mu\textrm{m}$ band and 10.4$\mu\textrm{m}$ band in $CO_2$. The output power profile obtained from each band is well consistent with the gain curve of $CO_2$ laser and maxium tuned output power was 20 watt.

• Journal of The Korean Astronomical Society
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• v.50 no.3
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• pp.41-49
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• 2017

We conduct BVRI and R band photometric observations of asteroid (5247) Krylov from January 2016 to April 2016 for 51 nights using the Korea Microlensing Telescope Network (KMTNet). The color indices of (5247) Krylov at the light curve maxima are determined as $B-V=0.841{\pm}0.035$, $V-R=0.418{\pm}0.031$, and $V-I=0.871{\pm}0.031$ where the phase angle is $14.1^{\circ}$. They are acquired after the standardization of BVRI instrumental measurements using the ensemble normalization technique. Based on the color indices, (5247) Krylov is classified as a S-type asteroid. Double periods, that is, a primary period $P_1=82.188{\pm}0.013h$ and a secondary period $P_2=67.13{\pm}0.20h$ are identified from period searches of its R band light curve. The light curve phases with $P_1$ and this indicate that it is a typical Non-Principal Axis (NPA) asteroid. We discuss the possible causes of its NPA rotation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.35-43
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• 2017

The minimum reinforcement ratio is an important design factor to prevent a brittle failure in RC flexural members. A minimum reinforcement ratio is presented by assuming an effective depth of cross-section and moment arm lever in CDC and KHBDC. In this study, it suggests that a rational method for minimum reinforcement ratio is calculated by material model and force equilibrium. As results, a minimum reinforcement ratio using a p-r curve in KHBDC is evaluated about 52~80% of recent design code's value and it induces an economical design. And also, a ductility capacity in case of placing this minimum reinforcement amount is evaluated about 89% of recent design code's value, but ductility in a member is 7 or more, so it has a sufficient ductility capacity. Therefore, it is judged that a minimum reinforcement ratio using p-r curve has a theoretical rationality, safety and economy in a flexural member design.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.505-508
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• 2006

Self-heating induced device degradation and its width/length (W/L) dimension dependence were studied in p-type polycrystalline silicon (poly-Si) thin film transistors (TFTs). Negative channel conductance was observed under high power region of output curve, which was mainly caused by hole trapping into gate oxide and also by trap state generation by self-heating effect. Self-heating effect became aggravated as W/L ratio was increased, which was understood by the differences in heat dissipation capability. By reducing applied power density normalized to TFT area, self-heating induced degradation could be reduced.

• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.47-56
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• 2004

A new fragmentation model, called the GRS (the generation model of weathered residual soils) model, was proposed in this study, This model could identify the formation of a residual soil. This model is based on the phenomena that as the soil was weathered more highly, soil particles were smaller and pores were more expanded simultaneously. The possibility of fragmentation, $P_F,$ which was based on the fractal theory, was introduced in this model. There were some fundamental notions in the GRS model that soil particles were generated as the rock is fragmented, and the fragmentation of the rock was performed step by step. The $P_F,$ of the rock was not constant at each fragmentation steps. As a result of application on the GRS model, there were more residue where $P_{Fi}s$ were small at any particle size. There was a S-shape of PSD curve at the concave shape of $P_{Fi},$ and the PSD curve goes to a gaped graded curve at the convex shape of $P_{Fi}.$ The shape of PSD curve was concave in the case of small $P_{Fi}s.$ The value of $P_{Fi}$ increased with the coefficient of uniformity $(C_u)$ and the fragmentation fractal dimension $(D_r),$ but had no relation with the coefficient of gradation $(C_C)$.