• Journal of Energy Engineering
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• v.25 no.1
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• pp.69-75
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• 2016

Bubble size is a key parameter for an accurate prediction of bubble behaviours in the multi-dimensional two-phase flow. In the current STAR CCM+ CFD code, a mechanistic bubble size model $S{\gamma}$ is available for the prediction of bubble size in the flow channel. As another model, Yun model is developed based on DEBORA that is subcooled boiling data in high pressure. In this study, numerical simulation for the gas-liquid two-phase flow was conducted to validate and confirm the performance of $S{\gamma}$ model and Yun model, using the commercial CFD code STAR CCM+ ver. 10.02. For this, local bubble models was evaluated against the air-water data from DEDALE experiments (1995) and Hibiki et al. (2001) in the vertical pipe. All numerical results of $S{\gamma}$ model predicted reasonably the two-phase flow parameters and Yun model is needed to be improved for the prediction of air-water flow under low pressure condition.

• Journal of IKEEE
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• v.9 no.2 s.17
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• pp.143-151
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• 2005

Finite failure NHPP models proposed in the literature exhibit is either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. For the sake of proposing shape parameter of the Gamma family distribution, used the special pattern. Data set, where the underlying failure process could not be adequately described by the knowing models, which motivated the development of the Gamma or Weibull model and Gompertz model. Analysis of failure data set that led us to the Gamma or Weibull model and Gompertz model using arithmetic and Laplace trend tests, bias tests was presented in this Paper.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.1829-1831
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• 2012

Background: The generalized gamma distribution statistics constitute an extensive family that contains nearly all of the most commonly used distributions including the exponential, Weibull and log normal. A saturated version of the model allows covariates having effects through all the parameters of survival time distribution. Accelerated failure-time models assume that only one parameter of the distribution depends on the covariates. Methods: We fitted both the conventional GG model and the saturated form for each of its members including the Weibull and lognormal distribution; and compared them using likelihood ratios. To compare the selected parameter distribution with log logistic distribution which is a famous distribution in survival analysis that is not included in generalized gamma family, we used the Akaike information criterion (AIC; r=l(b)-2p). All models were fitted using data for 369 women age 50 years or more, diagnosed with stage IV breast cancer in BC during 1990-1999 and followed to 2010. Results: In both conventional and saturated parametric models, the lognormal was the best candidate among the GG family members; also, the lognormal fitted better than log-logistic distribution. By the conventional GG model, the variables "surgery", "radiotherapy", "hormone therapy", "erposneg" and interaction between "hormone therapy" and "erposneg" are significant. In the AFT model, we estimated the relative time for these variables. By the saturated GG model, similar significant variables are selected. Estimating the relative times in different percentiles of extended model illustrate the pattern in which the relative survival time change during the time. Conclusions: The advantage of using the generalized gamma distribution is that it facilitates estimating a model with improved fit over the standard Weibull or lognormal distributions. Alternatively, the generalized F family of distributions might be considered, of which the generalized gamma distribution is a member and also includes the commonly used log-logistic distribution.

• Journal of applied mathematics & informatics
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• v.28 no.5_6
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• pp.1217-1225
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• 2010

In this paper we define fuzzy interior $\Gamma$-ideals in ordered $\Gamma$-semigroups. We prove that in regular(resp. intra-regular) ordered $\Gamma$-semigroups the concepts of fuzzy interior $\Gamma$-ideals and fuzzy $\Gamma$-ideals coincide. We prove that an ordered $\Gamma$-semigroup is fuzzy simple if and only if every fuzzy interior $\Gamma$-ideal is a constant function. We characterize intra-regular ordered $\Gamma$-semigroups in terms of interior (resp. fuzzy interior) $\Gamma$-ideals.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1460-1463
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• 1997

The aim of this paper is to suggest a design method of the model following optimal boiler-turbine H.inf. control system using genetic algorithm. This boiler-turbine H.inf. control system is designed by applying genetic algortihm with reference model to the optimal determination of weighting functions and design parameter .gamma. that are given by Glover-Doyle algornithm whch can design H.inf. contrlaaer in the sate. space. The first method to do this is ghat the gains of weightinf functions and .gamma. are optimized simultaneously by genetic algroithm. And the second method is that not only the gains and .gamma. but also the dynamics of weighting functions are optimized at the same time by genetic algonithm. The effectiveness of this boiler-turbine H.inf. control system is verified and compared with LQG/LTR control system by computer simulation.

• Journal of Family Resource Management and Policy Review
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• v.11 no.4
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• pp.55-71
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• 2007

The purpose of this study was to explore a self-diagnostic indicator for measuring a healthy family by adopting the theme of "happiness", which has surfaced as the most interesting in many academic fields recently. Though the basic concept of a healthy family may be shared by everyone, the criterion of happiness varies from one family to another. Therefore, it is desirable that the tool be made in such a way that every member of the family can check their health from a holistic perspective, rather than diagnosing health and happiness from the perspective of professionals. So, this study was aimed at diagnosing a family by using a tool named GAMMA model, so each family member can recognize problems and find the best options to solve it. This study. has a significant meaning in that it has tried to diagnose families by introducing the GAMMA model into domestic science for the first time.

• Journal of Korean Neurosurgical Society
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• v.43 no.1
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• pp.26-30
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• 2008

Objective : The authors developed a stereotactic device for irradiation of small animals with Leksell Gamma Knife Model C. Development and verification procedures were described in this article. Methods : The device was designed to satisfy three requirements. The mechanical accuracy in positioning was to be managed within 0.5 mm. The strength of the device and structure were to be compromised to provide enough strength to hold a small animal during irradiation and to interfere the gamma ray beam as little as possible. The device was to be used in combination with the Leksell G-$frame^{(R)}$ and $KOPF^{(R)}$ rat adaptor. The irradiation point was determined by separate imaging sequences such as plain X-ray images. Results : The absolute dose rate with the device in a Leksell Gamma Knife was 3.7% less than the value calculated from Leksell Gamma $Plan^{(R)}$. The dose distributions measured with $GAFCHROMIC^{(R)}$ MD-55 film corresponded to those of Leksell Gamma $Plan^{(R)}$ within acceptable range. The device was used in a series of rat experiments with a 4 mm helmet of Leksell Gamma Knife. Conclusion : A stereotactic device for irradiation of small animals with Leksell Gamma Knife Model C has been developed so that it fulfilled above requirements. Absorbed dose and dose distribution at the center of a Gamma Knife helmet are in acceptable ranges. The device provides enough accuracy for stereotactic irradiation with acceptable practicality.

• Journal of Korea Water Resources Association
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• v.36 no.2
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• pp.223-235
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• 2003

An indirect or supplementary approach is proposed for determining the parameters of the Clark's model in order to improve existing defect in estimating the parameters. The gamma-distribution type function is employed to represent the Clark's model, which takes the same form as the Nash's model, so that parameter estimation is not difficult since it can be performed with a simple optimization process. Analytic forms of Clark's models parameters are introduced using parameters of the proposed methodology to give traditional form of Clark's. An application to a watershed has shown that the proposed approach can preserve the properties of observed data. Based the application, the new approach is recommended as an alternative to the existing parameter estimating methodology.

• The Korean Journal of Applied Statistics
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• v.28 no.2
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• pp.221-230
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• 2015

Traditionally, sib-pair linkage analysis with repeated measures has employed linear mixed models, but it suffers from the lack of power to find genetic marker loci associated with a phenotype of interest. In this paper, we use a gamma mixed model to improve sib-pair linkage analysis and compare it with a linear mixed model in terms of power and Type I error. We illustrate that the use of gamma mixed model can achieve higher power than linear mixed model with Genetic Analysis Workshop 13 data.

• Journal of Radiation Industry
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• v.7 no.1
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• pp.55-59
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• 2013

Ionizing radiation causes the massive generation of reactive oxygen species, resulting in cellular and tissue damage. The present study was performed to evaluate ${\gamma}$-irradiation induced cellular damage in ICR mice. The mice were divided into four groups with ten mice in each group. Group 1 served as an unexposed control group. Groups 2, 3, and 4 were exposed to 3, 5, and 7 Gy of ${\gamma}$-radiation, respectively. Five mice per group were sacrificed 1 and 7 days after ${\gamma}$-radiation. Exposure to ${\gamma}$-irradiation resulted in hematopoietic damage in a dose-dependent manner when compared with the unexposed control group, which featured a significantly decreased spleen index. However, the exposed mice showed no significant differences in their serum AST, ALT and in the histopathological change of their liver. These results suggest that ${\gamma}$-irradiation is a good tool to prepare a hematopoietic damage model. This animal model can be employed to study the hematopoietic efficacy of biologically active compounds.