• Journal of Advanced Marine Engineering and Technology
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• v.23 no.5
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• pp.637-653
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• 1999

In this study well-known burned rate expressions of Weibe function and double Wiebe function have been adopted for the combustion analysis of large two stroke marine diesel engine. A cycle simulation program was also developed to predict the performance and pressure waves in pipes using validated burned rate function,. Levenberg-Marquardt iteration method was applied to cali-brate the shape coefficients included in double Wiebe function for the performance prediction of two-stroke marine diesel engine. As a result the performance prediction using double Wiebe func-tion is well correlated withexperimental dta with the accuracy of 5% and pressure waves in intake and transport pipe are well predicted. From the results of this study it can be confirmed that the shape coefficients of burned rate function should be modified using the numerical method suggested for the accurated prediction and double Wiebe function is more suitable than Wiebe func-tion for combustion analysis of large two stroke marine engine.

• Bulletin of the Korean Mathematical Society
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• v.33 no.2
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• pp.289-294
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• 1996

The double Gamma function had been defined and studied by Barnes [4], [5], [6] and others in about 1900, not appearing in the tables of the most well-known special functions, cited in the exercise by Whittaker and Waston [25, pp. 264]. Recently this function has been revived according to the study of determinants of Laplacians [8], [11], [15], [16], [19], [20], [22] and [24]. Shintani [21] also uses this function to prove the classical Kronecker limit formula. Its p-adic analytic extension appeared in a formula of Casson Nogues [7] for the p-adic L-functions at the point 0.

• Advances in concrete construction
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• v.1 no.4
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• pp.319-340
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• 2013

This paper presents a comparative study on the double-K fracture parameters of concrete obtained using four existing analytical methods such as Gauss-Chebyshev integral method, simplified Green's function method, weight function method and simplified equivalent cohesive force method. Two specimen geometries: three point bend test and compact tension specimen for sizes 100-500 mm at initial notch length to depth ratios 0.25 and 0.4 are used for the comparative study. The required input parameters for determining the double-K fracture parameters are derived from the developed fictitious crack model. It is found that the cohesive toughness and initial cracking toughness determined using weight function method and simplified equivalent cohesive force method agree well with those obtained using Gauss-Chebyshev integral method whereas these fracture parameters determined using simplified Green's function method deviates more than by 11% and 20% respectively as compared with those obtained using Gauss-Chebyshev integral method. It is also shown that all the fracture parameters related with double-K model are size dependent.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2007.11a
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• pp.592-601
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• 2007

In the conventional double auction approaches, two basic assumptions are usually applied - (1) each trader has a linear or quasi-linear utility function of price and quantity, (2) buyers as well as sellers have identical utility functions. However, in practice, these assumptions are unrealisitc. Therefore, a flexible and integrated double auction mechanism that can integrate all traders' diverse utility functions is necessary. We propose a double auction mechanism with resource allocation based on nonlinear utility functions, namely a flexible synchronous double auction system where each participant can express a diverse utility function on the price and quantity. In order to optimize the total market utility consists of multiple complex utility functions of traders, our study proposes a genetic algorithm (GA) We show the viability of the proposed mechanism through several simulation experiments.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.3
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• pp.59-65
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• 1992

In this paper, the Numerov method is applied to solve the Schroedinger equation for $Al_{0.3}Ga_{0.7}AS/GaAs/Al_{0.3}Ga_{0.7}As$ double-heterojunction HEMT structures. The 3 subband energy levels, corresponding wave functions, 2-dimensional electron gas density, and conduction band edge profile are calculated from a self-consistent iterative solution of the Schroedinger equation and the Poisson equation. In addition, 2-dimensional electron gas densities in a quantum well of double heterostructure are calculated as a function of applied gate voltage. The density in the double heterojunction quantum well is increased to about more than 90%, however, the transconductance of the double heterostructure HEMT is not improved compared to that of the single heterostructure HEMT. Thus, double-heterojunction structures are expected to be suitable to increase the current capability in a HEMT device or a power HEMT structure.

• International Journal of Concrete Structures and Materials
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• v.10 no.2
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• pp.163-175
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• 2016

This paper presents a revised procedure for computation of double-K fracture parameters of concrete split-tension cube specimen using weight function of the centrally cracked plate of finite strip with a finite width. This is an improvement over the previous work of the authors in which the determination of double-K fracture parameters of concrete for split-tension cube test using weight function of the centrally cracked plate of infinite strip with a finite width was presented. In a recent research, it was pointed out that there are great differences between a finite strip and an infinite strip regarding their weight function and the solution of infinite strip can be utilized in the split-tension specimens when the notch size is very small. In the present work, improved version of LEFM formulas for stress intensity factor, crack mouth opening displacement and crack opening displacement profile presented in the recent research work are incorporated. The results of the double-K fracture parameters obtained using revised procedure and the previous work of the authors is compared. The double-K fracture parameters of split-tension cube specimen are also compared with those obtained for standard three point bend test specimen. The input data required for determining double-K fracture parameters for both the specimen geometries for laboratory size specimens are obtained using well known version of the Fictitious Crack Model.

• Honam Mathematical Journal
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• v.36 no.2
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• pp.263-273
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• 2014

Ever since Euler solved the so-called Basler problem of ${\zeta}(2)=\sum_{n=1}^{\infty}1/n^2$, numerous evaluations of ${\zeta}(2n)$ ($n{\in}\mathbb{N}$) as well as ${\zeta}(2)$ have been presented. Very recently, Ritelli [61] used a double integral to evaluate ${\zeta}(2)$. Modifying mainly Ritelli's double integral, here, we aim at evaluating certain interesting alternating series.

• Computers and Concrete
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• v.9 no.2
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• pp.81-97
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• 2012

This paper presents development of double-K fracture model for the split-tension cube specimen for determining the unstable fracture toughness and initial cracking toughness of concrete. There are some advantages of using of split-tension cube test like compactness and lightness over the existing specimen geometries in practice such as three-point bend test, wedge splitting test and compact tension specimen. The cohesive toughness of the material is determined using weight function having four terms for the split-tension cube specimen. Some empirical relations are also suggested for determining geometrical factors in order to calculate stress intensity factor and crack mouth opening displacement for the same specimen. The results of double-K fracture parameters of split-tension cube specimen are compared with those obtained for compact tension specimen. Finally, the influence of the width of the load-distribution of split-tension cube specimen on the double-K fracture parameters for laboratory size specimens is investigated. The input data required for determining double-K fracture parameters for both the specimen geometries are obtained using well known version of the Fictitious Crack Model.

• Journal of the Korean Operations Research and Management Science Society
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• v.33 no.1
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• pp.19-33
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• 2008

In the previous double auction research for the market optimization, two basic assumptions are usually applied - (1) each trader has a linear or quasi-linear utility function of price and quantity, and (2) buyers as well as sellers have identical utility functions. However, in practice, each buyer and seller in a double auction market may have diverse utility functions for trading goods. Therefore, a flexible and integrated double auction mechanism that can integrate all traders' diverse utility functions is necessary. In particular, the flexible mechanism is more useful in a synchronous double auction because traders can properly change utilities in each round. Therefore, in this paper, we propose a flexible synchronous double auction mechanism in which traders can express diverse utility functions for the price and quantity of the goods, and optimal total market utility is guaranteed. In order to optimize the total market utility which consists of multiple complex utility functions of traders. We show the viability of the proposed mechanism through a several simulation experiments.

• Honam Mathematical Journal
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• v.40 no.4
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• pp.809-816
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• 2018

The aim of this research paper is to evaluate fifty double integrals invoving generalized hypergeometric function (25 each) in the form of $${{\int}^1_0}{{\int}^1_0}\;x^{{\gamma}-1}y^{{\gamma}+c-1}(1-x)^{c-1}(1-y)^{c+{\ell}}(1-xy)^{{\delta}-2c-{\ell}-1}{\times}_3F_2\[{^{a,\;b,\;2c+{\ell}+1}_{\frac{1}{2}(a+b+i+1),\;2c+j}}\;;{\frac{(1-x)y}{1-xy}}\]dxdy$$ and $${{\int}^1_0}{{\int}^1_0}\;x^{{\gamma}-1}y^{{\gamma}+c+{\ell}}(1-x)^{c+{\ell}}(1-y)^{c-1}(1-xy)^{{\delta}-2c-{\ell}-1}{\times}_3F_2\[{^{a,\;b,\;2c+{\ell}+1}_{\frac{1}{2}(a+b+i+1),\;2c+j}}\;;{\frac{1-y}{1-xy}}\]dxdy$$ in the most general form for any ${\ell}{\in}{\mathbb{Z}}$ and i, j = 0, ${\pm}1$, ${\pm}2$. The results are derived with the help of generalization of Edwards's well known double integral due to Kim, et al. and generalized classical Watson's summation theorem obtained earlier by Lavoie, et al. More than one hundred ineteresting special cases have also been obtained.