• 산업경영시스템학회지
• /
• 제20권43호
• /
• pp.287-297
• /
• 1997

This research is concerned with operation control problem for an automated manufacturing system which consists of two machine centers and a single automatic guided vehicle. The objective is to develop and evaluate heuristic scheduling procedures that minimize maximum completion time to be included travel time of AGV. A new heuristic algorithm is proposed and a numerical example illustrates the proposed algorithm. The heuristic algorithm is implemented for various cases by SLAM II. The results show that the proposed algorithm provides better solutions than the previous algorithms.

• 지질공학
• /
• 제19권2호
• /
• pp.205-215
• /
• 2009

지표하 다공성매체에서 비정상상태의 유동을 해석하기 위한 종래의 수치적 모형들은 초기 건조한 토양으로의 강우로 인한 침투와 같은 한계적인 유입경계조건인 경우에 국지적 유동영역으로 인해 수치적 진동 및 불안정성을 초래한다. 이러한 경우 주로 공간적으로 세분된 격자와 작은 계산시간 간격을 요구하는데 이는 계산의 효율성을 떨어뜨린다. 따라서 본 연구에서는 유입 경계조건을 포함하는 비정상 상태의 지표하 유동해석을 위해 입자추적 알고리즘을 적용하여 불연속영역에서의 수치적 불안정성을 제거하고자 하였다. 즉, 수치적 안정성이 개선된 혼합 LE 유한요소기법을 제시하였다. 제시된 모형의 수치적 검증을 위해 비정상 균일 유동장과 불균일 유동장의 가상예제에 적용한 결과 해석해와 유사한 결과를 얻을 수 있었고 이를 토대로 함양 및 양수에 대한 3차원 가상유역 모의에 적용되었다. 본 연구에서 제시한 입자추적 알고리즘은 포화 및 불포화 다공성 매체의 유동을 보다 실질적으로 모의할 수 있으며 계산의 정확성 및 안정성에 크게 기여할 것으로 판단되었다.

• 한국항공우주학회지
• /
• 제33권11호
• /
• pp.1-6
• /
• 2005

본 연구에서는 형상기억합금 작동기의 열-기계적 특성과 구조물의 응용을 살펴보았다. Lagoudas 모델을 기본으로 3-D 형상기억합금의 구성방정식을 FORTRAN으로 해석 알고리즘을 만들어 user material(UMAT) subroutine을 개발하였다. 개발된 형상기억합금 해석 UMAT subroutine을 상용 프로그램 ABAQUS와 연계 해석하여 형상기억합금 작동기와 주 구조물간의 상호 특성을 수치적으로 살펴보았다.

• 한국자동차공학회논문집
• /
• 제18권3호
• /
• pp.43-52
• /
• 2010

In this study, the shapes of the wheel and rail are represented by using 3-dimensional surface functions with surface parameters and a 3-dimensional wheel-rail contact analysis is presented. A whole numerical solution of wheel-rail contact at tread and flange including 2-point contacts can be achieved with the proposed numerical algorithm. Kinematic characteristics such as variances of vertical displacement and roll angle, and variance of wheel radius difference for arbitrary yaw and lateral displacement of wheelset, are determined for the KTX wheel-rail pair as an example. The condition of yaw and lateral displacement occurring 2-point contacts to analyze derailment are compared between standard and worn wheels. Differences of contact characteristics between curved and straight rails are also analyzed.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 춘계학술대회
• /
• pp.1821-1826
• /
• 2003

In this study, we discuss CIP method, which can treat compressible/incompressible problem and multi-phase problem. We can apply this method to the general equations by using CCUP. In this paper, non-staggered grid arrangement and predictor-corrector method are used to enhance later development and the solution accuracy and convergence performance. To validate the numerical algorithm proposed in this paper, the two-dimensional unsteady flow in the driven cavity is simulated. The numerical results of this subject using the present algorithm are compared with other numerical results. As a result, it is prived that the present scheme gives stable and improved solutions, and the results even coarse grid are in good agreement with other result using a fine grid arrangement.

• Computers and Concrete
• /
• 제22권1호
• /
• pp.1-10
• /
• 2018

In this study an implicit algorithm for modeling of propagation of macrocracks in 3D concrete structures suffering from alkali-silica reaction has been developed and implemented. The formulation of the problem prior to the onset of localized deformation is based on a chemo-elasticity approach. The localized deformation mode, involving the formation of macrocracks, is described using a simplified form of the strong discontinuity approach (SDA) that employs a volume averaging technique enhanced by a numerical procedure for tracing the propagation path in 3D space. The latter incorporates a non-local smoothening algorithm. The formulation is illustrated by a number of numerical examples that examine the crack propagation pattern in both plain and reinforced concrete under different loading scenarios.

• Journal of applied mathematics & informatics
• /
• 제35권1_2호
• /
• pp.165-180
• /
• 2017

In this study, Taylor matrix algorithm is designed for the approximate solution of linear and non-linear differential equation systems. The algorithm is essentially based on the expansion of the functions in differential equation systems to Taylor series and substituting the matrix forms of these expansions into the given equation systems. Using the Mathematica program, the matrix equations are solved and the unknown Taylor coefficients are found approximately. The presented numerical approach is discussed on samples from various linear and non-linear differential equation systems as well as stiff systems. The computational data are then compared with those of some earlier numerical or exact results. As a result, this comparison demonstrates that the proposed method is accurate and reliable.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2005년도 춘계 학술대회논문집
• /
• pp.123-127
• /
• 2005

The numerical analyses of the complicated flows are widely attempted in these days. Because of the enormous demanding memory and calculation time, parallel processing is used for these problems. In order to obtain calculation efficiency, it is important to choose proper domain decomposition technique and numerical algorithm. In this research we enhanced the efficiency of the CFDS code developed by ADD, using parallel computation and newly developed numerical algorithms. For the huge amount of data transfer between blocks non-blocking method is used, and newly developed data transfer algorithm is used for non-aligned block interface. Recently developed RoeM scheme is adpoted as a spatial difference method, and AF-ADI and LU-SGS methods are used as a time integration method to enhance the convergence of the code. Analyses of the flows around the ONERA M6 wing and the high angle of attack missile configuration are performed to show the efficiency improvement.

• 응용통계연구
• /
• 제25권4호
• /
• pp.661-668
• /
• 2012

For displaying multivariate numerical data on a 2D plane by the projection, principal components biplot and the GGobi are two main tools of data visualization. The biplot is very useful for capturing the global shape of the dataset, by representing $n$ observations and $p$ variables simultaneously on a single graph. The GGobi shows a dynamic movie of the images of $n$ observations projected onto a sequence of unit vectors floating on the $p$-dimensional sphere. Even though these two methods are certainly very valuable, there are drawbacks. The biplot is too condensed to describe the detailed parts of the data, and the GGobi is too burdensome for ordinary data analyses. In this paper, "the local projective display(LPD)" is proposed for visualizing multivariate numerical data. Main steps of the LDP are 1) $k$-means clustering of the data into $k$ subsets, 2) drawing $k$ principal components biplots of individual subsets, and 3) sequencing $k$ plots by Hurley's (2004) endlink algorithm for cognitive continuity.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 1999년도 제30회 추계학술대회
• /
• pp.146-153
• /
• 1999

A numerical dynamic simulation is necessary to investigate the capacity of the HDD. The slider surface become more and more complicated to make the magnetized area smaller and readback signal stronger. So a numerical dynamic simulation must be preceded to develop a new slider in HDD. The dynamic simulations of air-lubricated slider bearing have been peformed using FIFD(Factored Implicit Finite Difference) method. The governing equation, Reynolds equation Is modified with Fukui and Kaneko model(FK model) which includes the first and the second-order slip. The equations of motion for the slider bearing are solved simultaneously with the modified Reynolds equation for the case of three degrees of freedom. The slider transient response for disk step bump and slider impulse force is given for various case and for iteration algorithm and new algorithm.