• 제목/요약/키워드: Computation problem

검색결과 1,300건 처리시간 0.03초

Parametric Macro for Two-Dimensional Layout on the Auto-CAD System

  • Kim, Yunyong;Park, Jewoong
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2000년도 추계학술대회 논문집
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    • pp.253-260
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    • 2000
  • In recent years, a number of successful nesting approaches have been developed by using the various heuristic algorithms, and due to their application potential several commercial CAD/CAM packages include a nesting module for solving the layout problem. Since a large portion of the complexity of the part nesting problem results from the overlapping computation, the geometric representation is one of the most important factors to reduce the complexity of the problem. The proposed part representation method can easily handle parts and raw materials with widely varying geometrical shape by using the redesigning modules. This considerably reduces the amount of processed data and consequently the run time of the computer. The aim of this research is to develop parametric macro for two-dimensional layout on the Auto-CAD system. Therefore, this research can be called "pre-nesting".

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Integrated Inventory-Distribution Planning in a (1 : N) Supply Chain System with Heterogeneous Vehicles Incorporated

  • Kim, Eun-Seok;Lee, Ik-Sun
    • Management Science and Financial Engineering
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    • 제17권2호
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    • pp.1-21
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    • 2011
  • This paper considers an integrated inventory-distribution system with a fleet of heterogeneous vehicles employed where a single warehouse distributes a single type of products to many spatially distributed retailers to satisfy their dynamic demands. The problem is to determine order planning at the warehouse, and also vehicle schedules and delivery quantities for the retailers with the objective of minimizing the sum of ordering cost at the warehouse, inventory holding cost at both the warehouse and retailers, and transportation cost. For the problem, we give a Mixed Integer Programming formulation and develop a Lagrangean heuristic procedure for computing lower and upper bounds on the optimal solution value. The Lagrangean dual problem of finding the best Lagrangrean lower bound is solved by subgradient optimization. Computational experiments on randomly generated test problems showed that the suggested algorithm gives relatively good solutions in a reasonable amount of computation time.

무기-표적 할당 문제에 대한 메타휴리스틱의 성능 비교 (Comparative Study on Performance of Metaheuristics for Weapon-Target Assignment Problem)

  • 최용호;이영훈;김지은
    • 한국군사과학기술학회지
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    • 제20권3호
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    • pp.441-453
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    • 2017
  • In this paper, a new type of weapon-target assignment(WTA) problem has been suggested that reflects realistic constraints for sharing target with other weapons and shooting double rapid fire. To utilize in rapidly changing actual battle field, the computation time is of great importance. Several metaheuristic methods such as Simulated Annealing, Tabu Search, Genetic Algorithm, Ant Colony Optimization, and Particle Swarm Optimization have been applied to the real-time WTA in order to find a near optimal solution. A case study with a large number of targets in consideration of the practical cases has been analyzed by the objective value of each algorithm.

병렬기계에서 납기지연 가중 합을 최소화하기 위한 유전 알고리듬 (A Genetic Algorithm for the Parallel-Machine Total Weighted Tardiness Problem)

  • 박문원
    • 대한산업공학회지
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    • 제26권2호
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    • pp.183-192
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    • 2000
  • This paper considers the problem of scheduling a set of n jobs on m parallel machines to minimize total weighted tardiness. For the problem a genetic algorithm is proposed, in which solutions are encoded using the random key method suggested by Bean and new crossover operators are employed to increase performance of the algorithm. The algorithm is compared with the Modified Due-Date (MDD) algorithm after series of tests to find appropriate values for genetic parameters. Results of computational tests on randomly generated test problems show that the suggested algorithm performs better than the MDD algorithm and gives good solutions in a reasonable amount of computation time.

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Parametric Macro for Two-Dimensional Cutting Stock in Optimal Processing System of FMS

  • Park, Je-Woong;Kim, Yun-Young
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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    • pp.552-552
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    • 2000
  • In recent years, a number of successful nesting approaches have been developed by using the various heuristic algorithms, and due to their application potential several commercial CAD/CAM packages include a nesting module for solving the layout problem. Since a large portion of the complexity of the part nesting problem results from the overlapping computation, the geometric representation is one of the most important factors to reduce the complexity of the problem. The proposed part representation method can easily handle parts and raw materials with widely varying geometrical shape by using the redesigning modules. This considerably reduces the amount of processed data and consequently the run time of the computer. The aim of this research is to develop parametric macro for two-dimensional cutting stock on the Auto-CAD system. Therefore, this research can be called "pre-nesting"

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MOTION IN PARABOLIC CYLINDRICAL COORDINATES: APPLICATION TO J2 GRAVITY PERTURBED TRAJECTORIES

  • Sharaf, M.A.;Selim, H.H.;Saad, A.S.
    • 천문학회지
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    • 제39권4호
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    • pp.147-150
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    • 2006
  • In this paper, initial value problem for dynamical astronomy will be established using parabolic cylindrical coordinates. Computation algorithm is developed for the initial value problem of gravity perturbed trajectories. Applications of the algorithm for the problem of final state predication are illustrated by numerical examples of seven test orbits of different eccentricities. The numerical results are extremely accurate and efficient in predicating final state for gravity perturbed trajectories which is of extreme importance for scientific researches as well as for military purposes. Moreover, an additional efficiency of the algorithm is that, for each of the test orbits, the step size used for solving the differential equations of motion is larger than 70% of the step size used for obtaining its reference final state solution.

안전모의 충격전달에 관한 이론적 고찰 (A theoretical study on the shock-absorbing characteristic of safety helmet)

  • 김연우;박경수
    • 대한인간공학회지
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    • 제9권1호
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    • pp.29-33
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    • 1990
  • The need for the protection of workers in many industrial workstations has long been recognized, and many type of protective equipment have been devised. In many protective equipment designs, this study set limits to the safety helmet. The direct closed head impact problem was idealized as a linear-damped spring model. This study concerns what properties of helment should afford optimal protection in a direct closed head impact problem. The solution to the problem was achieved through analytic method and numerical computation. The answer was found in terms of 4 parameters : 1) rigidity of shell, 2) viscosity of shell, 3)rigidity of harness, 4) viscosity of harness. The choices are as follows 1) to reduce the rigidity value of harness as small as possible 2) to increase the viscosity value of harness as large as possible. 3) to select the rigidity value of shell sufficient for preventing a breakage.

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ON THE STUDY OF SOLUTION UNIQUENESS TO THE TASK OF DETERMINING UNKNOWN PARAMETERS OF MATHEMATICAL MODELS

  • Avdeenko, T.V.;Je, Hai-Gon
    • East Asian mathematical journal
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    • 제16권2호
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    • pp.251-266
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    • 2000
  • The problem of solution uniqueness to the task of determining unknown parameters of mathematical models from input-output observations is studied. This problem is known as structural identifiability problem. We offer a new approach for testing structural identifiability of linear state space models. The approach compares favorably with numerous methods proposed by other authors for two main reasons. First, it is formulated in obvious mathematical form. Secondly, the method does not involve unfeasible symbolic computations and thus allows to test identifiability of large-scale models. In case of non-identifiability, when there is a set of solutions to the task, we offer a method of computing functions of the unknown parameters which can be determined uniquely from input-output observations and later used as new parameters of the model. Such functions are called parametric functions capable of estimation. To develop the method of computation of these functions we use Lie group transformation theory. Illustrative example is given to demonstrate applicability of presented methods.

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블럭펄스 함수를 이용한 비선형 시스템의 최적제어 (Optimal Control of Nonlinear Systems Using Block Pulse Functions)

  • 조영호;안두수
    • 대한전기학회논문지:시스템및제어부문D
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    • 제49권3호
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    • pp.111-116
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    • 2000
  • In this paper, we presented a new algebraic iterative algorithm for the optimal control of the nonlinear systems. The algorithm is based on tow steps. The first step transforms optimal control problem into a sequence of linear optimal control problem using the quasilinearization method. In the second step, TPB(two point boundary condition problem) is solved by algebraic equations instead of differential equations using BPF(block pulse functions). The proposed algorithm is simple and efficient in computation for the optimal control of nonlinear systems. In computer simulation, the algorithm was verified through the optimal control design of Van del pole system and Volterra Predatory-prey system.

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원호와직선으로 구성된 도형간의 효율적인 최소거리 계산방법 (An Efficient Method for Minimum Distance Problem Between Shapes Composed of Circular Arcs and Lines)

  • 김종민;김민환
    • 대한전기학회논문지
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    • 제43권5호
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    • pp.848-860
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    • 1994
  • Generally, to get the minimum distance between two arbitrary shapes that are composed of circular arcs and lines, we must calculate distances for all the possible pairs of the components from two given shapes. In this paper, we propose an efficient method for the minimum distance problem between two shapes by using their structural features after extracting the reduced component lists which are essential to calculate the minimum distance considering the relationship of shape location. Even though the reduced component lists may contain all the components of the shapes in the worst case, in the average we can reduce the required computation much by using the reduced component lists. This method may be efectively applied to calculating the minimum distance between two shapes which are generated by the CAD tool, like in the nesting system.

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