• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
• /
• pp.389-395
• /
• 2004

We consider the interface between the parallel distributed memory multifrontal solver and the finite element method. We give in detail the requirement and the data structure of parallel FEM interface which includes the element data and the node array. The full procedures of solving a large scale structural problem are assumed to have pre-post processors, of which algorithm is not considered in this paper. The main advantage of implementing the parallel FEM interface is shown up in the case that we use a distributed memory system with a large number of processors to solve a very large scale problem. The memory efficiency and the performance effect are examined by analyzing some examples on the Pegasus cluster system.

• 대한산업공학회지
• /
• 제12권2호
• /
• pp.21-31
• /
• 1986

Consider a capacitated facility location problem in which the demands of customers are all equal and so are the capacities of facilities. Under the restriction that each customer's uniform demand be met by exactly one facility, the objective is to select a set of facilities to open, and to assign customer's demand to them so as to minimize the total cost which includes fixed costs of opening facilities as well as variable assignment costs. The problem is modelled as a pure zero-one program which may be viewed as a variant of well-known capacitated facility location problems. The purpose of this study is to develop efficient computational procedures for solving the pure zero-one facility location problems. Due to the special structure of our zero-one location problem with uniform demand, it can be converted to a location problem with the unimodular property. A Lagrangean relaxation algorithm is developed to solve the location problem. The algorithm is made efficient by employing a device which exploits the special structure of a surrogate constraint. The efficiency of the algorithm is analyzed through computational experiments with some test problems.

• Wind and Structures
• /
• 제19권1호
• /
• pp.35-58
• /
• 2014

A numerical simultaneous solution involving a linear elastic model was applied to study the fluid-structure interaction (FSI) of membrane structures under wind actions, i.e., formulating the fluid-structure system with a single equation system and solving it simultaneously. The linear elastic model was applied to managing the data transfer at the fluid and structure interface. The monolithic equation of the FSI system was formulated by means of variational forms of equations for the fluid, structure and linear elastic model, and was solved by the Newton-Raphson method. Computation procedures of the proposed simultaneous solution are presented. It was applied to computation of flow around an elastic cylinder and a typical FSI problem to verify the validity and accuracy of the method. Then fluid-structure interaction analyses of a saddle membrane structure under wind actions for three typical cases were performed with the method. Wind pressure, wind-induced responses, displacement power spectra, aerodynamic damping and added mass of the membrane structure were computed and analyzed.

• 전기의세계
• /
• 제29권10호
• /
• pp.678-688
• /
• 1980

This paper is concerned with the computer design of the multiple-output switching functions by using the improved MASK method in order to obtain the paramount prime implicants (prime implicants of the multiple-output switching function) and new algorithm to design the optimal logic network. All the given minterms for each function are considered as minterms of one switching function to simplify the desigh procedures. And then the improved MASK method whose memory requirement and time consuming are much less than any existing known method is applied to identify the paramount prime implicants. In selecting the irredundant paramount prime implicants, new cost criteria are generated. This design technuque is suitable both for solving a problem by hand or programming it on a digital computer.

• 한국구조물진단유지관리공학회 논문집
• /
• 제6권3호
• /
• pp.129-138
• /
• 2002

The purpose of this study is to propose the nonlinear analysis method which combines the nonlinear incremental method with the layered method to solve the problems due to the geometric and the material nonlinearities. As numerical analysis models, the reinforced concrete simple beam and the steel arch frame are used to verify the algorithm of the proposed nonlinear method. The results are gotten from the computation procedures. According to the results of this study, the fracture pattern of the beam according to the ratio of tensile steel and the strength of the concrete and the steel can be estimated by the proposed method. Therefore, the load-deflection curve of structure can be, exactly, depicted by the proposed method. Also, the rupture load, the site and the depth of crack of the beam can analytically be checked by the proposed method. In this respect, the proposed method contributes for the solving the stability problem of the actual structure.

• 산업경영시스템학회지
• /
• 제38권4호
• /
• pp.64-71
• /
• 2015

In this paper, we present a multi-period 0-1 knapsack problem which has the cardinality constraints. Theoretically, the presented problem can be regarded as an extension of the multi-period 0-1 knapsack problem. In the multi-period 0-1 knapsack problem, there are n jobs to be performed during m periods. Each job has the execution time and its completion gives profit. All the n jobs are partitioned into m periods, and the jobs belong to i-th period may be performed not later than in the i-th period, i = 1, ${\cdots}$, m. The total production time for periods from 1 to i is given by $b_i$ for each i = 1, ${\cdots}$, m, and the objective is to maximize the total profit. In the extended problem, we can select a specified number of jobs from each of periods associated with the corresponding cardinality constraints. As the extended problem is NP-hard, the branch and bound method is preferable to solve it, and therefore it is important to have efficient procedures for solving its linear programming relaxed problem. So we intensively explore the LP relaxed problem and suggest a polynomial time algorithm. We first decompose the LP relaxed problem into m subproblems associated with each cardinality constraints. Then we identify some new properties based on the parametric analysis. Finally by exploiting the special structure of the LP relaxed problem, we develop an efficient algorithm for the LP relaxed problem. The developed algorithm has a worst case computational complexity of order max[$O(n^2logn)$, $O(mn^2)$] where m is the number of periods and n is the total number of jobs. We illustrate a numerical example.

• 농촌지도와개발
• /
• 제5권1호
• /
• pp.11-30
• /
• 1998

The lack of close working relationship between agricultural research, extension organizations and farmers, is one of the most difficult problems confronting agricultural technology system. Systems approach is an effective method to use in indentifying lingkage problems in agricultural technology system, and it is a problem-solving methodology. There are two basic types of linkage mechanisms; organizational and managerial. Organizational mechanisms involve the structural modification of the research and extension organizations involved in an agricultural technology system. The other major type of lingkage mechanisms involves a range of managerial interventions such as joint planning and review activities, collaborative program activities, and resource allocation procedures, etc.

• 한국정보전자통신기술학회논문지
• /
• 제13권2호
• /
• pp.102-112
• /
• 2020

스마트시티의 목표는 스마트시티의 요소기술을 통해 도시문제를 해결하여 친환경적이고 지속가능한 경제발전 및 시민의 삶의 질을 향상하는 것이라 할 수 있다. 지금까지 스마트시티는 요소기술 중심으로 발전해왔지만 이제는 스마트시티에서 생활을 하는 시민들의 니즈나 참여에 대해 관심을 두어야 할 때이다. 본 논문에서는 시민 니즈와 참여를 기반으로 스마트시티의 문제해결을 위한 빅 데이터 절차를 제시한다. 이를 위하여 지역별 주요산업별 스마트시트 프로젝트 시장과 분야별 스마트시티 시장 영역 발전단계를 살펴본다. 또한 시민 참여에 대한 분야별 정의와 필요성을 이해하고 빅 데이터를 통한 문제해결 방법으로 7단계 빅 데이터 문제해결 프로세스에 접목 방안을 제시한다. 문제해결을 위한 7단계 빅데이터 프로세스는 스마트시티의 각 부문별 정형·비정형 데이터 수집 분석 후 과제를 도출하고 이에 따른 정책 프로그램을 도출하는 방법이다. 이러한 절차에 시민 참여를 이끌어 내기 위하여 비정형 데이터 수집과정에서 디자인싱킹 방법론의 공감단계를 활용한다. 또한 스마트시티 도시문제 해결을 위한 시민 니즈를 찾는 방법으로 비정형 데이터 분석과정에 디자인싱킹 방법론의 문제정의 단계를 접목시켰다.

• 전기의세계
• /
• 제49권9호
• /
• pp.9-16
• /
• 2000

A receding horizon $H_{\infty}$ predictive control method is derived by solving a min-max problem in non-recursive forms. The min-max cost index is converted to a quadratic form which for systems with input saturation can be minimized using QP. Through the use of closed-loop prediction the prediction of states the use of closed-loop prediction the prediction of states in the presence of disturbances are made non-conservative and it become possible to get a tighter $H_{\infty}$ norm bound. Stability conditions and $H_{\infty}$ norm bounds on disturbance rejection are obtained in infinite horizon sence. Polyhedral types of feasible sets for sets and disturbances are adopted to deal with the input constraints. The weight selection procedures are given in terms of LMIs and the algorithm is formulated so that it can be solved via QP. This work is a modified version of an earlier work which was based on ellipsoidal type feasible sets[15].

• Journal of Mechanical Science and Technology
• /
• 제18권1호
• /
• pp.45-54
• /
• 2004

In order to meet the requirement for higher thickness accuracy in cold rolling processes, it is strongly desired to have high performance in control units. To meet this requirement, we have considered an output regulating control system with a roll-eccentricity estimator for each rolling stand of tandem cold mills. Considering entry thickness variation as well as roll eccentricity as the major disturbances, a synthesis of multivariable control systems is presented based on H$\sub$$\infty$/ control theory, which can reflect the knowledge of input direction and spectrum of disturbance signals on the design. Then, to reject roll eccentricity effectively, a weight function having some poles on the imaginary axis is introduced. This leads to a non-standard H_ control problem, and the design procedures for solving this problem are analytically presented. The effectiveness of the proposed control method is evaluated through computer simulations and compared to that of the conventional LQ control and feedforward control methods for roll eccentricity.