• Journal of the Korean Data and Information Science Society
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• v.23 no.1
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• pp.199-207
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• 2012

Recently, variable selection methods using penalized likelihood with a shrink penalty function have been widely studied in various statistical models including generalized linear models and survival models. In particular, they select important variables and estimate coefficients of covariates simultaneously. In this paper, we develop a penalize h-likelihood method for variable selection in gamma frailty models. For this we use the smoothly clipped absolute deviation (SCAD) penalty function, which satisfies a good property in variable selection. The proposed method is illustrated using simulation study and a practical data set.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.8
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• pp.1895-1900
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• 2010

In this paper, we propose the hardware architecture of a display converter which is consisted of four functional blocks. The four functional blocks consists of a set of color space converter, de-interacer, video display scaler, and gamma corrector. After the proposed architecture was implemented into hardware, we verified that it operated exactly. The designed hardware has 7,629 LUT and 6,800 Logic Register in Stratix device of Altera and operates in 270 MHz clock frequency.

• Bulletin of the Korean Mathematical Society
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• v.37 no.1
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• pp.191-207
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• 2000

Let R be a ommutative ring with unity and F a finite free R-module. For a nonnegative integer r, there exists a natural filtration of$S_r(S_2F)$ such that its associated graded module is isomorphic to $\Sigma_{{\lambda}{\epsilon}{\tau}_r}\;L_{\lambda}F$, where ${\Gamma}_{\gamma}$ set of partitions such that $$\mid${\lambda}$\mid$-2r,{{\widetilde}{\lambda}}-{{\widetilde}{\lambda}}_1},...,{{\widetilde}{\lambda}}_k},\;each\;{{\widetilde}{\lambda}}_t}$,is even. We call such filtrations plethysm formulas. We extend the above plethysm formula to the version of chain complexes. By plethysm formula we mean the composition of universally free functors. $Let{\emptyset}:G->F$ be a morphism of finite free R-modules. We construct the natural decomposition of $S_{r}(S_2{\emptyset})$,up to filtrations, whose associated graded complex is isomorphic to ${\Sigma}_{{\lambda}{\varepsilon}{\tau}}_r}\;L_{\lambda}{\emptyset}$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.2
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• pp.193-199
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• 2015

We observed that the growth and physiological change in Haliotis discus discus by low-dose irradiation with gamma ray.Irradiation with gamma ray was undertaken by using the low-level irradiation facility ($^{60}CO$) in cooperation with the Institute of Nuclear Science and Technology at Jeju National University. The parent abalones were attached one by one and then fixed by using the rubber band to the front side of the fabricated case for irradiation with gamma ray. The experimental plots of irradiation with gamma ray were set as 10, 15, 20 and 25 Gy and the 25 female abalones and 10 male abalones were utilized for each experimental plot. The sperms and eggs were fertilized by setting an interval for each dose to prevent mixing with other experimental plots when fertilizing the sperms and eggs for each dose of irradiation with gamma ray. As for the fertility, it was confirmed to be 85% the control and 10 Gy groups, whereas it was found to be 80%, 65% and 50% in the 15 Gy, 20 Gy and 25 Gy groups, respectively. As a conclusion, the hatching rate and attachment rate were higher at 10 and 15 Gy than the other experimental plots, and the growth rate was higher at 20 Gy than the other experimental plots. Also the changes in lysozyme activity in accordance with the stress of water temperature were found to have a significant increase in the other experimental plots as compared with the control plot at the end of 0 h. The changes in lysozyme activity have remained constant in all the experimental plots at the end of 12 h. These results allowed us to confirm that lysozyme was undertaking the biodefense action by reacting sensitively to the stress of water temperature in the control experimental plot. As for the other experimental plots, they are believed to avoid the biodefense mechanism due to the high degree of anti-parasite mechanism and anti-viral mechanism. Thus, it is believed that it would be imperative to conduct development and research on breeds that were potent for environmental tolerance by applying the method of irradiation with gamma ray to other marine animals and plants.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1156-1164
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• 2010

Structured lipids (SLs) were synthesized by enzymatic interesterification with evening primrose oil (EPO) and rice bran oil (RBO) in a batch-type reactor. The interesterification was performed using a water shaker for 24 hr at $55^{\circ}C$. Mixing speed was set at 200 rpm and Lipozyme RM IM (immobilized lipase from Rhizomucor miehei, 10% by weight of total substrates) was used as a biocatalyst. Rice bran oil and evening primrose oil were interesterified with various molar ratios (RBO : EPO, 1:3, 1:4, and 1:5 mol/mol). Reversed-phase high performance liquid chromatography connected with evaporative light-scattering detector was performed to separate the triacylglycerol (TAG) species of SLs. In the fatty acid analysis, $\gamma$-linolenic acid (7.9 mol%), linoleic acid (67.3 mol%) and oleic acid (13.2 mol%) were the most abundant fatty acids in the SLs. During 24 hr reaction, most of the reaction occurred within 3 hr. TAG compositions, tocopherols and phytosterols were also analyzed. In the TAG species analysis, LLL (ECN=42, L=linoleic acid) dramatically decreased when the reaction time increased.

• Progress in Medical Physics
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• v.24 no.3
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• pp.198-203
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• 2013

Generally, to evaluate gated radiation therapy, moving phantoms are used to simulate organ motion. Since the target moves in every direction, we need to take into account motion in each direction. This study proposes methods to evaluate gated radiation therapy using gamma index analysis and to visualize adequate gating window sizes according to motion ranges. The moving phantom was fabricated to simulate motion in the craniocaudal direction. This phantom consisted of a moving platform, the I'm MatriXX, and solid water phantoms. A 6 MV photon filed with a field size of $4{\times}4cm^2$ was delivered to the phantom using the gating system, while the phantom moved in the 1-, 2-, 3-, 4-, and 5-cm motion ranges. The gating windows were set at 40~60%, 30~40%, and 0~90%, respectively. The I'm MatriXX acquired the dose distributions for each scenario and the dose distributions were compared with a $4{\times}4cm^2$ static filed. The tolerance of the gamma index was set at 3%/3 mm. The greater the gating window, the lower the pass rate, and the greater the motion range, the lower the pass rate in this study. In case treatment without gated radiation therapy for the target with motion of 2 cm, the pass rate was less than 96%. But it was greater than 99% when gated radiation therapy was used. However gated radiation therapy was used for the target with motion greater than 4 cm, the pass rate could not be greater than 97% when gating window was set as 30~70%. But when the gating window set as 40~60%, the pass rate was greater than 99%.

• Korea journal of population studies
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• v.29 no.2
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• pp.53-88
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• 2006

The major aim of this paper is to develop a hypothetical set of age-specific fertility rates which are logically derived and reasonably accurate in the projection of future population. The first procedure is to select a generalized log-gamma distribution model, which includes Coale-McNeil nuptiality model, in order to estimate and project a set of age-specific fertility rates by birth cohort and birth order. The second is to apply the log-gamma model with an empirical adjustment to the actual data to estimate and project the future fertility rates for relatively young birth cohorts who did not complete their reproductive career. This study reconstructs or translates a set of cohort age-specific fertility rates into a set of period age-specific fertility rates which must be hypothesized in order to establish the broader framework of future population projection. For example, the fertility at age 20 in the year of 2020 is the fertility at age 20 for the cohort born in 1990, while the fertility at age 21 in the year of 2020 is the fertility at 21 for the cohort born in 1989. In turn, once a set of age-specific fertility rates for the cohorts who were born up to the year of 2010, it is possible for one to establish an hypothetical set of period age-specific fertility rates which will be needed to project the future population until the year of 2055. The difference in the hypothetical system of age-specific fertility rates between this study and the 2005 special population projection comes from the fact that the fertility estimation/projection model used in this study was skillfully exploited to reflect better actual trend of fertility decline caused by rise in marriage age and increasing proportion of those who remain single until their end of reproduction. In this regard, this paper argues that the set of age-specific fertility rates derived from this study is more logical and reasonably accurate than the set of those used for the 2005 special projection. In the population projection, however, the fundamental issue of the hypothetical setting of age-specific fertility rates in relation to the fertility estimation/projection model is about how skillfully one can handle the period effects. It is not easy for one to completely cope with the problem of period effects except for the a minor period adjustment based on recent actual data, along with the given framework of a cohort-based fertility estimation/projection model.

• Restorative Dentistry and Endodontics
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• v.9 no.1
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• pp.81-87
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• 1983

The purpose of this study was to observe and identify the phases of amalgam and to know the transformation of microstructure in the set amalgam by lapse of time. In this study, shofu spherical-D alloy was used. After trituration of amalgam alloy and mercury (Wig-L-Bug), it was filled in the stone dies. This specimens being polished and etched by usual method was observed under optical microscope using metallurgical microscope. And then X-ray diffractometer was used to analyze the phases contents and transformation of microstructure at $2{\frac{1}{2}}$ hours, 15 hours, 28 hours and 2 years after being amalgamated. The following results were obtained: 1. Shofu spherical-D alloy powder was composed of ${\gamma}$ phase, ${\epsilon}$phase and Ag-Cu eutectic phases. 2. ${\gamma}_2$ phases were appeared at $2{\theta}$ values ($32.0^{\circ}$ and $43.8^{\circ}$) in the amalgam which was analyzed at $2{\frac{1}{2}}$ hours and 15 hours after trituration with mercury. 3. In the amalgam at 28 hours, ${\gamma}_2$ phase was found at $2{\theta}$ value ($43.8^{\circ}$) at 35 hour, $r_2$ phase was appeared at $2{\theta}$ value $32.0^{\circ}$. 4. No ${\gamma}_2$ phases were observed in the 2 years old amalgam. But ${\eta}$ ($Cu_6Sn_5$) phases were found at $2{\eta}$ values $29.4^{\circ}$ and $42.4^{\circ}$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.2
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• pp.223-230
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• 2012

The strength of brittle material has commonly been characterized by a normal distribution or Weibull distribution, but it may fit the gamma distribution for some material. The use of an extreme value distribution is proper when the largest values of a set of stresses dominate the failure of the material. This paper presents a formula for reliability estimation based on stress-strength interference theory that is applicable when the strength of material is distributed like a gamma distribution and the stress is distributed like an extreme value distribution. We verified the validity of the equation for the reliability estimation by examining the relationships among the factor of safety, the coefficient of variation, and the reliability. The required minimum factor of safety and the highest allowable coefficient of variation of stress can be estimated by choosing an objective reliability and estimating the reliabilities obtained for various factors of safety and coefficients of variation.

• Communications of the Korean Mathematical Society
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• v.28 no.1
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• pp.11-24
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• 2013

The notion of intersectional soft sets is introduced, and several examples are given. The application of intersectional soft sets to BCK/BCI-algebras is discussed.