• 제목/요약/키워드: Problem Determination

검색결과 798건 처리시간 0.026초

Shape determination of 3-D reinforcement corrosion in concrete based on observed temperature on concrete surface

  • Kurahashi, Takahiko;Oshita, Hideki
    • Computers and Concrete
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    • 제7권1호
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    • pp.63-81
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    • 2010
  • We present the shape determination method of 3-D reinforcement corrosion based on observed temperature on concrete surface. The non-destructive testing for reinforcement corrosion in concrete using a heat image on concrete surface have been proposed by Oshita. The position of the reinforcement of corrosion or the cavity can be found using that method. However, the size of those defects can not be precisely measured based on the heat image. We therefore proposed the numerical determination system of the shape for the reinforcement corrosion using the observed temperature on the concrete surface. The adjoint variable method is introduced to formulate the shape determination problem, and the finite element method is employed to simulate the heat transfer problem. Some numerical experiments and the examination for the number of the observation points are shown in this paper.

자금 제약하에서의 동시조달부품의 최적 구매량 결정 (Optimal Provisioning Quantity Determination of Concurrent Spare Part under the Funds Limitation)

  • 오근태
    • 산업경영시스템학회지
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    • 제20권41호
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    • pp.123-134
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    • 1997
  • In this paper we consider the CSP requirements determination problem of new equipment system. The CSP we deal with in the paper are restricted to the demand-based spare parts. For the newly procured equipment systems, mathematical analyses are made for the system which is constructed with the repairable items to derive the associated CSP requirement determination model in mathematical expression, respectively. Based on these analyses, a mathematical model is derived for making an optimal CSP requirement determination subject to the constraint of satisfying any given funds limitation. We assume that the failure of a part follows a Poisson process. Firstly, the operational availability concept in CSP is defined and the relation between the general system availability and the operational availability is established. Secondly, the problem is formulated as the operational availability maximization problem that should satisfy the funds limitation, and then, using the generalized Lagrange multipliers method, the optimal solution procedure is derived.

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운용가용도 제약하에서의 소모성 동시조달부품의 최적구매량 결정 (Optimal Provisioning Quantity Determination of Consumable Concurrent Spare Part under the Availability Limitation)

  • 오근태;김명수
    • 산업경영시스템학회지
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    • 제21권48호
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    • pp.113-122
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    • 1998
  • In this paper we consider the CSP requirements determination problem of new equipment(machine) system. For the newly procured equipment systems, mathematical analyses are made for the system which is constructed with the consumable parts to derive the associated CSP requirement determination model in mathematical expression. Based on these analyses, a mathematical model is derived for making an optimal CSP requirement determination subject to tile constraint of satisfying any given operational availability limitation. We assume that the failure of a part follows a Poisson process. Firstly, the operational availability concept in CSP is defined and the relation between the general system availability and the operational availability is established. Secondly, the problem is formulated as the cost minimization problem that should satisfy the operational availability limitation, and then, using the generalized Lagrange multipliers method, the optimal solution procedure is derived.

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운용가용도 제약하에서 소모성부품과 수리순환부품이 혼재된 동시조달부품의 최적구매량 결정 (Optimal Provisioning Quantity Determination of Concurrent Spare Parts including Consumable Items and Repairable Items under the Availability Limitation)

  • 오근태;김명수
    • 산업경영시스템학회지
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    • 제23권59호
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    • pp.53-67
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    • 2000
  • In this paper we consider the CSP requirements determination problem of new equipment(machine) system. For the newly procured equipment systems, mathematical analyses are made for the system which is constructed with the consumable parts and the repairable parts to derive the associated CSP requirement determination model in mathematical expression. Based on these analyses, a mathematical model Is derived for making an optimal CSP requirement determination subject to the constraint of satisfying any given operational availability limitation. We assume that the failure of a part follows a Poisson process and the repair time has an exponential distribution. Firstly, the operational availability concept in CSP is defined and the relation between the general system availability and the operational availability is established. Secondly, the problem is formulated as the cost minimization problem that should satisfy the operational availability limitation, and then, using the generalized Lagrange multipliers method, the optimal solution procedure Is derived.

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Finite element procedure of initial shape determination for hyperelasticity

  • Yamada, Takahiro
    • Structural Engineering and Mechanics
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    • 제6권2호
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    • pp.173-183
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    • 1998
  • In the shape design of flexible structures, it is useful to predict the initial shape from the desirable large deformed shapes under some loading conditions. In this paper, we present a numerical procedure of an initial shape determination problem for hyperelastic materials which enables us to calculate an initial shape corresponding to the prescribed deformed shape and boundary condition. The present procedure is based on an Arbitrary Lagrangian-Eulerian (ALE) finite element method for hyperelasticity, in which arbitrary change of shapes in both the initial and deformed states can be treated by considering the variation of geometric mappings in the equilibrium equation. Then the determination problem of the initial shape can be formulated as a nonlinear problem to solve the unknown initial shape for the specified deformed shape that satisfies the equilibrium equation. The present approach can be implemented easily to the finite element method by employing the isoparametric hypothesis. Some basic numerical results are also given to characterize the present procedure.

A STUDY OF GENERALIZED ADAMS-MOULTON METHOD FOR THE SATELLITE ORBIT DETERMINATION PROBLEM

  • Hong, Bum Il;Hahm, Nahmwoo
    • Korean Journal of Mathematics
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    • 제21권3호
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    • pp.271-283
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    • 2013
  • In this paper, a generalized Adams-Moulton method that is a $m$-step method derived by using the Taylor's series is proposed to solve the satellite orbit determination problem. We show that our proposed method has produced much smaller error than the original Adams-Moulton method. Finally, the accuracy performance is demonstrated in the satellite orbit correction problem by giving a numerical example.

지구동주기위성의 위치보전해석과 궤도결정 (Station Keeping Analysis and Orbit Determination of Feosynchronous Satellite)

  • 박수홍;조겸래
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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    • pp.783-787
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    • 1993
  • The dynamics for a two-body problem including perturbations due to nonspherical gravitation of the earth, gravitation of the sun and moon, radiation of the sun is studied. Orbit determination was performed by SVD filter. The simulation result shows that the characteristics of the satellite orbit have east-west and south-north drift. Therefore, the periodic magnitude of the control time and value in the view of the periodicity of error can be provided, and this result can be basic data to a station keeping problem with an orbit determination result.

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Satellite Orbit Determination using the Particle Filter

  • Kim, Young-Rok;Park, Sang-Young
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
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    • 한국우주과학회 2011년도 한국우주과학회보 제20권1호
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    • pp.25.4-25.4
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    • 2011
  • Various estimation methods based on Kalman filter have been applied to the real-time satellite orbit determination. The most popular method is the Extended Kalman Filter (EKF) and the Unscented Kalman Filter (UKF). The EKF is easy to implement and to use on orbit determination problem. However, the linearization process of the EKF can cause unstable solutions if the problem has the inaccurate reference orbit, sparse or insufficient observations. In this case, the UKF can be a good alternative because it does not contain linearization process. However, because both methods are based on Gaussian assumption, performance of estimation can become worse when the distribution of state parameters and process/measurement noise are non-Gaussian. In nonlinear/non-Gaussian problems the particle filter which is based on sequential Monte Carlo methods can guarantee more exact estimation results. This study develops and tests the particle filter for satellite orbit determination. The particle filter can be more effective methods for satellite orbit determination in nonlinear/non-Gaussian environment.

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장비 수율을 고려한 가공경로선정과 투입량 결정에서의 유전알고리즘 접근 (Machining Route Selection and Determination of Input Quantity with Yield Using Genetic Algorithm)

  • 이규용
    • 한국산업경영시스템학회:학술대회논문집
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    • 한국산업경영시스템학회 2002년도 춘계학술대회
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    • pp.99-104
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    • 2002
  • This paper addresses a problem of machining route selection and determination of input quantity with yield in multi-stage flexible flow system. The problem is formulated as nonlinear programing and the proposed model is solved by genetic algorithm(GA) approach. The effectiveness of the proposed GA approach is evaluated through comparisons with the optimal solution obtained from the branch and bound for the same problem.

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네트워크 분할 기법을 이용한 기계 그룹 형성 알고리즘 (A Machine Cell Formation Algorithm Using Network Partition)

  • 최성훈
    • 산업경영시스템학회지
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    • 제27권3호
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    • pp.106-112
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    • 2004
  • This paper presents a new heuristic algorithm for the machine cell(MC) formation problem. MC formation problem is represented as an unbalanced k-way network partition and the proposed algorithm uses four stage-approach to solve the problem. Four stages are natural sub-network formation, determination of intial vertexes for each sub-network, determination of initial partition, and improvement of initial partition. Results of experiments show that the suggested algorithm provides near optimal solutions within very short computational time.