• Journal of the Korean Data and Information Science Society
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• v.16 no.4
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• pp.1017-1026
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• 2005

We consider the problem of modeling count data where the observation period is determined by the survival time of the individual under study. We assume random effects or frailty model to allow for a possible association between the death times and the counts. We assume that, given a random effect, the death times follow a Weibull distribution with a rate that depends on some covariates. For the counts, given the random effect, a Poisson process is assumed with the intensity depending on time and the covariates. A gamma model is assumed for the random effect. Maximum likelihood estimators of the model parameters are obtained. The model is applied to data set of patients with breast cancer who received a bone marrow transplant. A model for the time to death and the number of supportive transfusions a patient received is constructed and consequences of the model are examined.

• Journal of the Korean Mathematical Society
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• v.50 no.4
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• pp.865-877
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• 2013

The disjoint union of mapping class groups of surfaces forms a braided monoidal category $\mathcal{M}$, as the disjoint union of the braid groups $\mathcal{B}$ does. We give a concrete and geometric meaning of the braidings ${\beta}_{r,s}$ in $\mathcal{M}$. Moreover, we find a set of elements in the mapping class groups which correspond to the standard generators of the braid groups. Using this, we can define an obvious map ${\phi}\;:\;B_g{\rightarrow}{\Gamma}_{g,1}$. We show that this map ${\phi}$ is injective and nongeometric in the sense of Wajnryb. Since this map extends to a braided monoidal functor ${\Phi}\;:\;\mathcal{B}{\rightarrow}\mathcal{M}$, the integral homology homomorphism induced by ${\phi}$ is trivial in the stable range.

• Bulletin of the Korean Mathematical Society
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• v.40 no.1
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• pp.149-157
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• 2003

Let M be an exponentially bounded o-minimal expansion of the standard structure R = (R ,＋,.,<) of the field of real numbers. We prove that if r is a non-negative integer, then every definable $C^{r}$ manifold is affine. Let f : X ${\longrightarrow}$ Y be a definable $C^1$ map between definable $C^1$ manifolds. We show that the set S of critical points of f and f(S) are definable and dim f(S) < dim Y. Moreover we prove that if 1 < s < ${\gamma}$ < $\infty$, then every definable $C^{s}$ manifold admits a unique definable $C^{r}$ manifold structure up to definable $C^{r}$ diffeomorphism.

• Communications for Statistical Applications and Methods
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• v.22 no.2
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• pp.105-120
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• 2015

A large family of distributions arising from distributions of ordered data is proposed which contains other models studied in the literature. This extension subsume many cases of weighted random variables such as order statistics, records, k-records and many others in variety. Such a distribution can be used for modeling data which are not identical in distribution. Some properties of the theoretical model such as moment, mean deviation, entropy criteria, symmetry and unimodality are derived. The proposed model also studies the problem of parameter estimation and derives maximum likelihood estimators in a weighted gamma distribution. Finally, it will be shown that the proposed model is the best among the previously introduced distributions for modeling a real data set.

• ETRI Journal
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• v.33 no.5
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• pp.826-829
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• 2011

Distributed systems particularly suffer from Sybil attacks, where a malicious user creates numerous bogus nodes to influence the functions of the system. In this letter, we propose a Bloom filter-based scheme, SybilBF, to fight against Sybil attacks. A Bloom filter presents a set of Sybil nodes according to historical behavior, which can be disseminated to at least n (e-1)/e honest nodes. Our evaluation shows that SybilBF outperforms state of the art mechanisms improving SybilLimit by a factor of (1/e)${\gamma}$ at least.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.2
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• pp.128-132
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• 2010

Photonic crystal is dielectric materials or a set of different dielectric materials with periodic structure. Line defect is obtained by leaving out a row of rods along the $\Gamma$-X direction. We showed the change of group velocity in waveguide mode and found resultant small group velocity. Characteristics of the small group velocity were described by electric field distribution. Investigating the phase shift, it is confirmed if small group velocity is positive or negative.

• The Pure and Applied Mathematics
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• v.30 no.4
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• pp.429-442
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• 2023

In this paper, we introduce the concept of fuzzy ideals, anti-fuzzy ideals of Γ-BCK-algebras. We study the properties of fuzzy ideals, anti-fuzzy ideals of Γ-BCK-algebras. We prove that if f^-1(µ) is a fuzzy ideal of M, then µ is a fuzzy ideal of N, where f : M → N is an epimorphism of Γ-BCK-algebras M and N.

• Journal of Periodontal and Implant Science
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• v.28 no.1
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• pp.103-120
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• 1998

Prokaryotic and eukaryotic cells respond to heat stress and other environmental abuses by synthesizing a small set of stress proteins and by inhibiting post-transcription synthesis of normal proteins. The purpose of the present study was to document the stress response produced by inflamed gingival tissue in vivo, and cytokine inducted human periodontal ligament cells. Human PDL cells were exposed to TNF-$\alpha$(1ng/ml), INF-$\gamma$(200 U/ml), LPS(100ug/ml), combination of cytokine, and SDS-PAGE gels running and Western blotting analysis was done. In vivo studies, the healthy gingival tissusse of a control group and inflamed gingival tissue of adult periodontitis were studied by immunohistochemistry and histology. The results were as follows 1. HSP 47 was distributed on basal layer in healthy gingiva, but stronger stained in basal, suprabasal, and spinous layer of inflamed gingiva. 2. HSP 47 was rare on endothelial cells and mononuclear cells in healthy gingiva, but stronger expressed in inflamed gingiva. 3. HSP 70 expression was rare on epihelium and inflammatory cells hi both healthy & inflamed gingiva. 4. HSP 70 was actively expressed on endothelial cells and inflammatory cells of capillary lumen in moderately & mild inflamend gingiva. 5. PDL cells showed low level of HSP 47 protein expression which was significantly induced by cytokine stimulation (LSP only and combination). 6. Maximum HSP 70 protein induction was seen with stimulation by a combination of the cytokine, Combination of TNF-$\alpha$, INF-$\gamma$, LPS have been shown to synergistically effects of HSP 70 expression. On the above findings, HSP Is influenced by cytokine and chronic inflammation in vivo, and may be involved in protection of tissue during periodontal inflammatiom.

• Journal of the Korea Convergence Society
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• v.10 no.10
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• pp.99-105
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• 2019

In this study, the flow analysis around vehicle was carried out on various kinds of roof box models installed at the roof of vehicle. Through the analysis of fluid flow and pressure, we investigated which model was more suitable for driving. The four types of models were designed with their respective shapes of models 1, ${\beta}$, ${\delta}$ and ${\gamma}$, and the driving speed of car was set as 20 m/s. It was confirmed that the pressure for model ${\beta}$ became greatest compared to other models. And model ${\delta}$ has the lowest pressure among all models of roof boxes by installing a canoe with the structure for cable type. As the design data with the durability of roof box obtained on the basis of this study result are utilized, the esthetic sense can be shown by being grafted onto the car body at real life.

• Journal of radiological science and technology
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• v.46 no.5
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• pp.417-425
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• 2023

The glomerular filtration rate (GFR) has been the subject of much research as a key indicator for diagnosing, treating, and monitoring kidney function. The gamma camera method (Gates method) is simple and allows simultaneous acquisition of GFR and renal scintigraphy for each kidney, however its accuracy is inferior. This study aimed to investigate changes in GFR depending on how region of interest (ROI) are set up, which is one of many factors influencing accuracy. GFR was calculated by setting the ROI for each phase of the image acquisition time (Gates-1: 0~1 minutes, Gates-2: 1~3 minutes, Gates-3: 3~27 minutes), and statistical significance was verified based on probability value 0.05 through ANOVA analysis. While there was no statistically significant difference among results from Gates-1, 2, 3 (p=0.481>0.05), overall results from the Gates method tended to overestimate compared to those from the multiple blood sampling-dual exponential (MBSDE) method. When comparing averages between phases, results from Gates-2 were most similar to those from the MBSDE method. Moreover, paired t-test p-values between MBSDE method and phases were as follows Gates-1: 0.021 (p<0.05), Gates-2: 0.280 (p>0.05), and Gates-3: 0.164 (p>0.05) indicating that only Gates-1 had statistically significant differences compared with MBSDE method. Thus, setting ROI around 2~3 minutes is calculated can aid in accurately determining GFR when Gates Method.