• 수산경영론집
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• 제25권2호
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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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• 제48권5호
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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-${\beta}$.

• 대한교통학회지
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• 제25권5호
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• pp.209-231
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• 2007

이 논문은 통행선택행위를 간접효용함수 대신 체감비용을 비교하는 평가방법을 제시하였다. 체감비용 비교방법은 가계생산이론을 통행자가 통행비용과 시간 등 정량적 요소와 함께 안락성과 안전성 등 정량적 요소를 동시에 고려하는 경우에 적용하여 도출되었다. 이 분석에서는 통행행위가 통행목적 달성과 함께 여러 정성적 요소를 동시에 산출하는 과정을 기술하는 특수한 형태의 동차 공동생산함수를 고안하여 이용하였다. 통행대안별 체감비용은 금전적인 통행비용에 시간가치 중에서 정량적 요소에 대해 통행자가 느끼는 기회비용을 제한 값을 합하여 산출하였다. 이러한 체감비용은 통계적 측정가능조건을 충족시킬뿐더러 통행선택행위를 보다 합리적으로 설명할 수 있어, 통행선택에 대한 통계분석에서 간접효용함수에 비해 통계측정 대상으로서 보다 우수하다.

• Structural Engineering and Mechanics
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• 제56권4호
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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.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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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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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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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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• 제55권3호
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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.

• 호남수학학술지
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• 제42권3호
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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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• 제48권1호
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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.

• 한국전산구조공학회논문집
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• 제26권1호
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• pp.79-87
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• 2013

레벨셋방법과 헤비사이드 강화를 이용한 아이소-지오메트릭 위상최적설계 방법을 개발하였다. 레벨셋 방법에서는 초기해석영역은 고정되어 있으며 경계는 레벨셋 함수값을 이용한 암시적인 동적 경계로 표현되며, 이는 복잡한 위상적 변화를 용이하게 표현할 수 있게 한다. 헤비사이드 강화는 기존의 기저함수에 내부 경계를 표현하는 강화 함수를 더함으로써 아이소-지오메트릭 해석법의 정밀도를 향상시킨다. 제안된 위상 최적설계 방법은 다음과 같은 이점을 갖는다. 아이소-지오메트릭 해석법을 이용하여 정밀한 기하 형상을 얻을 수 있으며 텐서 곱을 이용하여 정의된 패치의 한계를 헤비사이드 강화를 이용함으로써 해결할 수 있다. 단일 패치를 사용함으로써 연속적인 응력 분포를 얻어낼 수 있을 뿐 아니라 불연속적인 변위장 또한 표현해 낼 수 있다. 레벨셋 방법론이 암시적 동적 경계를 잘 표현하기 때문에 이를 이용하여 헤비사이드 강화를 이용한 아이소-지오메트릭 해석법에서 위상의 변화를 잘 표현해 낼 수 있다.