• The Journal of Fisheries Business Administration
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• v.25 no.2
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• pp.47-58
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• 1994

This paper tries to estimate cost and profit functions under Cobb - Douglas production technology in the coastal fishing, using duality theory of production technology and cost function. Therefore this paper estimates in advance the production functions with two input variables, the number of working persons per tonage(WEMP) and the number of fishing equipment per tonage(WEQU). Then this paper estimates profit function and implicit cost function using the estimated coefficients from production functions. The results of this study show that the annual average profit pertonage of long bag set fishing and trap fishing amount to 4.1 million won and 3.9 million won respectively.

• Structural Engineering and Mechanics
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• v.48 no.5
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• pp.711-736
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• 2013

In this paper new implicit time integration called N-IHOA is presented for dynamic analysis of high damping systems. Here, current displacement and velocity are assumed to be functions of the velocities and accelerations of several previous time steps, respectively. This definition causes that only one set of weighted factors is calculated from the Taylor series expansion which leads to a simple approach and reduce the computational efforts. Moreover a comprehensive study on stability of the proposed method i.e., N-IHOA compared with IHOA integration which is performed based on amplification matrices proves the ability of the N-IHOA in high damping vibrations such as control systems. Also, wide range of numerical examples which contains single/multi degrees of freedom, damped/un-damped, free/forced vibrations from finite element/finite difference demonstrate that the accuracy and efficiency of the proposed time integration is more than the common approaches such as the IHOA, the Wilson-${\theta}$ and the Newmark-${\beta}$.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.209-231
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• 2007

This paper suggested an approach to characterize travel choice behaviors using the implicit price instead of the indirect utility. The choice criterion to compare the implicit prices of available trip options was developed from the utility maximization problem of a trip maker which is supposed to choose the best option from the available ones differentiated by only by the quantitative attributes such as travel cost and time but also by qualitative attributes such as comfort and safety. The utility maximization problem is constructed under household production theory, and is incorporated with a special kind of joint homogeneous production functions. The implicit price of a certain trip option is the sum of the monetary price and the multiple of travel time and the value-of-travel-time, and the value-of-travel-time refers to the portion of wage, which can be assignable to the trip-making activity. This choice criterion is statistically identifiable, and behaviorally plausible. Moreover, this criterion has the expression simpler than the indirect utility, and therefore could be an effective target of the statistical estimation for travel choice behaviors.

• Structural Engineering and Mechanics
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• v.56 no.4
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• pp.549-567
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• 2015

A first-order moment method (FORM) reliability analysis is commonly used for structural stability analysis. It requires the values and partial derivatives of the performance to function with respect to the random variables for the design. These calculations can be cumbersome when the performance functions are implicit. A Gaussian process (GP)-based response surface is adopted in this study to approximate the limit state function. By using a trained GP model, a large number of values and partial derivatives of the performance functions can be obtained for conventional reliability analysis with a FORM, thereby reducing the number of stability analysis calculations. This dynamic renewed knowledge source can provide great assistance in improving the predictive capacity of GP during the iterative process, particularly from the view of machine learning. An iterative algorithm is therefore proposed to improve the precision of GP approximation around the design point by constantly adding new design points to the initial training set. Examples are provided to illustrate the GP-based response surface for both structural and non-structural reliability analyses. The results show that the proposed approach is applicable to structural reliability analyses that involve implicit performance functions and structural response evaluations that entail time-consuming finite element analyses.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.249-252
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• 1996

This paper presents an algorithmic approach used in the development of a task-level off-line programming system for the efficient applicaiton of robot. In the method, robot tasks are graphically described with manipulation functions. By applying robot language these graphic robot tasks are converted into commands for the robot. A programming example demonstrates the potentiality of task-oriented robot programming.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.497-502
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• 1992

In this paper, a new design technique called Task Based Design (TBD) is proposed to design an optimal robot manipulator for a given task. Optimal design of a manipulator is difficult because it involves implicit and highly nonlinear functions of many design variables for a complex task. TBD designs an optimal manipulator which performs a given task best, by using a framework called Progressive Design which decomposes the complexity of the task into three steps: kinematic design, planning and kinematic control. An example of TBD is presented to demonstrate the efficiency and effectiveness of our framework.

• Kyungpook Mathematical Journal
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• v.55 no.3
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• pp.597-614
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• 2015

In this paper, we study some properties of the generalized Apostol type Hermite-based polynomials. which extend some known results. We also deduce some properties of the generalized Apostol-Bernoulli polynomials, the generalized Apostol-Euler polynomials and the generalized Apostol-Genocchi polynomials of high order. Numerous properties of these polynomials and some relationships between $F_n{^{({\alpha})}}(x;{\lambda};{\mu};{\nu};c)$ and $_HF_n{^{({\alpha})}}(x;{\lambda};{\mu};{\nu};c)$ are established. Some implicit summation formulae and general symmetry identities are derived by using different analytical means and applying generating functions.

• Honam Mathematical Journal
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• v.42 no.3
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• pp.477-499
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• 2020

In this paper, we introduce a new class of generalized Apostol-type Frobenius-Euler-Hermite polynomials and derive some explicit and implicit summation formulae and symmetric identities by using different analytical means and applying generating functions. These results extend some known summations and identities of generalized Frobenius-Euler type polynomials and Hermite-based Apostol-Euler and Apostol-Genocchi polynomials studied by Pathan and Khan, Kurt and Simsek.

• Steel and Composite Structures
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• v.48 no.1
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• pp.73-88
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• 2023

This paper presents a novel implicit level set method for topology optimization of functionally graded (FG) structures with pre-existing discontinuities (pre-cracks) using radial basis functions (RBF). The mathematical formulation of the optimization problem is developed by incorporating RBF-based nodal densities as design variables and minimizing compliance as the objective function. To accurately capture crack-tip behavior, crack-tip enrichment functions are introduced, and an eXtended Finite Element Method (X-FEM) is employed for analyzing the mechanical response of FG structures with strong discontinuities. The enforcement of boundary conditions is achieved using the Hamilton-Jacobi method. The study provides detailed mathematical expressions for topology optimization of systems with defects using FG materials. Numerical examples are presented to demonstrate the efficiency and reliability of the proposed methodology.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.1
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• pp.79-87
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• 2013

An isogeometric topological shape optimization method is developed using the level sets and Heaviside enrichments. In the level set method, the initial domain is kept fixed and its boundary is represented by an implicit moving boundary embedded in the level set functions, which facilitates to handle complicated topological shape changes. The Heaviside enrichment improves the isogeometric analysis by adding some enrichment functions to model the internal boundaries. The proposed topological shape optimization method has several benefits: exact geometric models can be obtained using the isogeometric approach and the limitation of tensor-product patches can be overcome using the Heaviside enrichments to represent the internal voids. Even in a single patch, discontinuous displacement fields as well as smooth stress field can be obtained. Since the level sets offer the implicit moving boundary inside the domain, it is easy to represent the topological shape variations in the isogeometric analysis using Heaviside enrichments.