• Communications for Statistical Applications and Methods
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• v.17 no.6
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• pp.845-852
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• 2010

The outcomes of counts commonly occur in the area of disease mapping for mortality rates or disease rates. A Poisson distribution is usually assumed as a model of disease rates in conjunction with a gamma prior. The small area typically refers to a small geographical area or demographic group for which very little information is available from the sample surveys. Under this situation the model-based estimation is very popular, in which the auxiliary variables from various administrative sources are used. The empirical Bayes estimator under Poissongamma model has been considered with its accuracy measures. An accuracy measure using a bootstrap samples adjust the underestimation incurred by the posterior variance as an estimator of true mean squared error. We explain the suggested method through a practical dataset of hitters in baseball games. We also perform a Monte Carlo study to compare the accuracy measures of mean squared error.

• Journal of Korean Neurosurgical Society
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• v.54 no.2
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• pp.107-111
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• 2013

Objective : We investigated the effectiveness of stereotactic gamma knife Radiosurgery (GKR) for radioresistant brain metastases with the impact upon histology. Methods : Between April 2004 and May 2011, a total of 23 patients underwent GKR for 67 metastatic brain tumors from 12 renal cell cancers, 5 sarcomas and 6 melanomas. The mean age was 56 years (range, 18 to 79 years). Most of the patients were classified as the Radiation Therapy Oncology Group recursive partitioning analysis class II (91.3%). The synchronous metastasis was found in 6 patients (26.1%) and metachronous metastasis in 17 patients (73.9%). We analyzed the local control rate, intracranial progression-free survival (PFS) and overall survival (OS). Results : The mean tumor volume for GKR was 2.24 cc and the mean prescription dose was 19.4 Gy (range, 10 to 24) to the tumor margin. Out of metachronous metastases, the median duration to intracranial metastasis was 3.3 years in renal cell cancer (RCC), 2.4 years in melanoma and 1.1 years in sarcoma (p=0.012). The total local control rate was 89.6% during the mean 12.4 months follow-up. The six-month and one-year local control rate was 90.2% and 83% respectively. Depending on the pathology, the control rate of RCC was 95.7%, sarcoma 91.3% and melanoma 80.5% during the follow-up. The common cause of local failure was the tumor bleeding in melanoma. The median PFS and OS were 5.2 and 8.4 months in RCC patients, 6.5 and 9.8 months in sarcoma, and 3.8 and 5.1 months in melanoma. Conclusion : The GKR can be one of the effective management options for the intracranial metastatic tumors from the radioresistant tumors. The melanoma showed a poor local control rate compared to other pathologies because of the hemorrhage.

• The Journal of Korean Society for Radiation Therapy
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• v.35
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• pp.15-21
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• 2023

Purpose: The purpose of this study is to compare the performance of the anisotropic analytical algorithm (AAA) and portal dose image prediction (PDIP) for patient-specific quality assurance based on electronic portal imaging device, and to evaluate the clinical feasibility of portal dosimetry using AAA. Subjects and methods: We retrospectively selected a total of 32 patients, including 15 lung cancer patients and 17 liver cancer patients. Verification plans were generated using PDIP and AAA. We obtained gamma passing rates by comparing the calculated distribution with the measured distribution and obtained MLC positional difference values. Results: The mean gamma passing rate for lung cancer patients was 99.5% ± 1.1% for 3%/3 mm using PDIP and 90.6% ± 5.8% for 1%/1 mm. Using AAA, the mean gamma passing rate was 98.9% ± 1.7% for 3%/3 mm and 87.8% ± 5.2% for 1%/1 mm. The mean gamma passing rate for liver cancer patients was 99.9% ± 0.3% for 3%/3 mm using PDIP and 96.6% ± 4.6% for 1%/1 mm. Using AAA, the mean gamma passing rate was 99.6% ± 0.5% for 3%/3 mm and 89.5% ± 6.4% for 1%/1 mm. The MLC positional difference was small at 0.013 mm ± 0.002 mm and showed no correlation with the gamma passing rate. Conclusion: The AAA algorithm can be clinically used as a portal dosimetry calculation algorithm for patientspecific quality assurance based on electronic portal imaging device.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.10
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• pp.4609-4614
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• 2016

Purpose: To evaluate the therapeutic effects of copper reduction on angiogenesis-related factors in patients with glioblastoma multiforme treated by gamma knife radiosurgery. Materials and Methods: In the present block randomized, placebo-controlled trial, fifty eligible patients with a diagnosis of glioblastoma multiforme who were candidates for gamma knife radiosurgery were randomly assigned into two groups to receive daily either 1gr penicillamine and a low copper diet or placebo for three months. The intervention started on the same day as gamma knife radiosurgery. Serum interleukin-6 (IL-6), tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$), vascular endothelial growth factor (VEGF) and copper levels were measured at baseline and after the intervention. The serum copper level was used as the final index of compliance with the diet. In order to control probable side effects of intervention, laboratory tests were conducted at the beginning, middle and end of the study. Results: The patients had a mean age and Karnofsky Performance Scale of 43.7 years and 75 respectively. Mean serum copper levels were significantly reduced in intervention group. Mean survival time was 18.5 months in intervention group vs. 14.9 in placebo group. VEGF and IL-6 levels in the intervention group were also significantly reduced compared to the placebo group and $TNF-{\alpha}$ increased less. Conclusions: It seems that reducing the level of copper in the diet and dosing with penicillamine leads to decline of angiogenesis-related factors such as VEGF, IL-6 and $TNF-{\alpha}$. Approaches targeting angiogenesis may improve survival and can be used as a future therapeutic strategy.

• Korean Journal of Mathematics
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• v.21 no.4
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• pp.365-374
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• 2013

Let $k=\mathbb{F}_q(T)$ be a rational function field over the finite field $\mathbb{F}_q$, where q is a power of an odd prime number, and $\mathbb{A}=\mathbb{F}_q[T]$. Let ${\gamma}$ be a generator of $\mathbb{F}^*_q$. Let $\mathcal{H}_n$ be the subset of $\mathbb{A}$ consisting of monic square-free polynomials of degree n. In this paper we obtain an asymptotic formula for the mean value of $L(1,{\chi}_{\gamma}{\small{D}})$ and calculate the average value of the ideal class number $h_{\gamma}\small{D}$ when the average is taken over $D{\in}\mathcal{H}_{2g+2}$.

• Journal of Radiation Protection and Research
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• v.30 no.4
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• pp.167-174
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• 2005

The concentrations of natural and artificial radionuclides in soil and gamma ray dose rate in air at 233 locations in Korea have been determined. The national mean concentrations of $^{232}Th,\;^{226}Ra,\;^{40}K,\;^{137}Cs\;and\;^{90}Sr$ in soil were $60{\pm}31,\;33{\pm}14,\;673{\pm}238,\;35{\pm}9.3\;and\;5.0{\pm}3.4\;Bq\;kg^{-1}$, respectively. The mean gamma-ray dose rate at 1 m above the ground was $7918\;nGy\;h^{-1}$. $^{137}Cs$ concentration had highly significant correlation with organic matter content and cation exchange capacity. $^{90}Sr$ concentration had slightly coherent with pH. The results have been compared with other global radioactivity and radiation measurements.

• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.216-223
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• 2017

In this work, linear and mass attenuation coefficients, effective atomic number and electron density, mean free paths, and half value layer and $10^{th}$ value layer values of barium-bismuth-borosilicate glasses were obtained for 662 keV, 1,173 keV, and 1,332 keV gamma ray energies using MCNP-4C code and XCOM program. Then obtained data were compared with available experimental data. The MCNP-4C code and XCOM program results were in good agreement with the experimental data. Barium-bismuth-borosilicate glasses have good gamma ray shielding properties from the shielding point of view.

• Macromolecular Research
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• v.17 no.6
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• pp.388-396
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• 2009

The surface properties (water sorption and repellency, adhesion) are closely related to the surface tension of polymer solids. The critical surface tension (${\gamma}_c$) and surface tension (${\gamma}_s$) of a polymer solid were estimated by the contact angle method by our quantitative imaging system. BPDA (3,3',4,4'-biphenyl tetracarboxylic dianhydride)-BAPP (1,3-Bis(4-aminophenoxy) propane) polyimide was successfully synthesized. The ${\gamma}_c$ values were analyzed by a Zisman plot, a Young-$Dupr\acute{e}$-Good-Girifalco plot, and a log ($1+cos{\theta}$) vs log ${\gamma}_L$ plot. The ${\gamma}_s$ value of BPDA-BAPE polyimide was evaluated using the geometric mean equation and our multiple regression analysis. The calculated values of ${{\gamma}_s^d$ (a dispersion component), ${{\gamma}_s^p$ (a polar component), ${{\gamma}_s^h$ (a hydrogen bonding component), and ${\gamma}_s$ were 30.79, 9.32, 0.20, and 40.31 $mN{\cdot}m^{-1}$, respectively. The ${\gamma}_s$ of BPDA-BAPP polyimide containing both a methylene group and an ether group was larger than that of the polyimide containing only a methylene group.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.12
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• pp.1203-1209
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• 2011

In this paper, the degradation evaluation method of VLC (Visible Light Communication) wireless module after high dose rate gamma-ray irradiation using the thermal infrared camera is proposed. First, the heating characteristics of the active devices embedded in the VLC wireless module during the condition of normal operation is monitored by thermal infrared camera. By the image processing technique, the trends of the intensity of the heat emitted by the active devices are calculated and stored. The feature of the blob area including the area of the active devices in the thermal infrared image is extracted and stored. The feature used in this paper is the mean value of the gray levels in the blob area. The same VLC module has been gamma irradiated at the dose rate of about 4.0 kGy/h during 72 hours up to a total dose of 288 kGy. And then, the heating characteristics of the active devices embedded in the VLC wireless module after high dose gamma ray irradiation is observed by thermal infrared camera. The high dose gamma-ray induced degradation of the active devices embedded in the VLC module was evaluated by comparing the mean value of the blob area to the one of the same blob area of the VLC module before the gamma ray irradiation.

• Water for future
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• v.26 no.4
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• pp.73-83
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• 1993

This study focuses on the separation effect analysis of rainfall data for 2-parameter log-normal, 3-parameter log-normal, type-extreme value, 2-parameter gamma, 3-parameter gamma, log-Pearson type-III, and general extreme value distribution functions. Difference in the relationship between the mean and standard deviation of skewness for historical data and relations derived from 7 distribution functions are analyzed suing the Monte Carlo experiment. The results show that rainfall data has the separation effect for 6 distribution functions except 3-parameter gamma distribution function.