• 제목/요약/키워드: near optimal solution

검색결과 213건 처리시간 0.022초

Seismic behavior of isolated bridges with additional damping under far-field and near fault ground motion

  • Losanno, Daniele;Hadad, Houman A.;Serino, Giorgio
    • Earthquakes and Structures
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    • 제13권2호
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    • pp.119-130
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    • 2017
  • This paper presents a numerical investigation on the seismic behavior of isolated bridges with supplemental viscous damping. Usually very large displacements make seismic isolation an unfeasible solution due to boundary conditions, especially in case of existing bridges or high risk seismic regions. First, a suggested optimal design procedure is introduced, then seismic performance of three real bridges with different isolation systems and damping levels is investigated. Each bridge is studied in four different configurations: simply supported (SSB), isolated with 10% damping (IB), isolated with 30% damping (LRB) and isolated with optimal supplemental damping ratio (IDB). Two of the case studies are investigated under spectrum compatible far-field ground motions, while the third one is subjected to near-fault strong motions. With respect to different design strategies proposed by other authors, results of the analysis demonstrated that an isolated bridge equipped with HDLRBs and a total equivalent damping ratio of 70% represents a very effective design solution. Thanks to confirmed effective performance in terms of base shear mitigation and displacement reduction under both far field and near fault ground motions, as well as for both simply supported and continuous bridges, the suggested control system provides robustness and reliability in terms of seismic performance also resulting cost effective.

유전자알고리즘 및 경험법칙을 이용한 1차원 부재의 최적 절단계획 (Optimal Cutting Plan for 1D Parts Using Genetic Algorithm and Heuristics)

  • 조경호
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집C
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    • pp.554-558
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    • 2001
  • In this study, a hybrid method is used to search the pseudo-optimal solution for the I-dimentional nesting problem. This method is composed of the genetic algorithm for the global search and a simple heuristic one for the local search near the pseudo optimal solution. Several simulation results show that the hybrid method gives very satisfactory results.

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A Shortest Path Dynamic Programming for Expansion Sequencing Problems

  • Kim, Sheung-K.
    • 대한산업공학회지
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    • 제12권1호
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    • pp.81-94
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    • 1986
  • A shortest path dynamic programming formulation is proposed and attemped to solve an uncapacitated expansion sequencing problem. It is also compared with the Extended Binary State Space approach with total capacity. Difficulties and merits associated with the formulation are discussed. The shortest path dynamic programming lacks the separability condition and an optimal solution is not guaranteed. However it has other merits and seems to be the practical solution procedure for the expansion sequencing problem in a sense that it finds near optimal solution with less state evaluations.

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MIMO 시스템에서 부분 검색 공간 기반의 검파기법 (A New Subspace Search-based Method for MIMO Systems)

  • 남상호;고균병;홍대식
    • 대한전자공학회논문지TC
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    • 제48권5호
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    • pp.25-32
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    • 2011
  • 본 논문에서는 MIMO 시스템에서 최적의 수신 성능을 제공하면서 낮은 복잡도를 요구하는 부분 검색 공간 기반의 검파 기법이 제안된다. 최적의 최대 우도 검파기는 신호의 전체 검색 공간을 활용하기 때문에 많은 복잡도를 요구하게 되는 데, 이에 대한 해결 방안으로 신호의 부분 검색 공간에 기반한 부분 후보 심볼 벡터 생성 기법이 제안된다. 또한, 최적의 수신 성능을 제공하기 위해서 전체 검색 공간에 기반한 전체 후보 심볼 벡터 생성 기법이 제안된다. 결론적으로 제안하는 부분 검색 공간 기반의 검파 기법은 MIMO 시스템에서 낮은 복잡도를 필요하면서 최적의 수신 성능을 제공하는 검파기법으로 사용될 수 있다.

진입로 신호등 시스템을 위한 SDRE 기반 최적 비선형 관측기 제어기 설계 (SDRE Based Optimal Nonlinear Observer-Controller Design for Ramp Metering System)

  • 이기호;최한호
    • 제어로봇시스템학회논문지
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    • 제20권5호
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    • pp.533-536
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    • 2014
  • In this paper, a near optimal decentralized observer-controller design method is proposed for ramp metering systems based on SDRE (State Dependent Riccati Equation) approach. The optimal nonlinear observer gain is parameterized in terms of the solution matrix of an SDRE. This paper gives a simple algorithm to compute the near optimal observer gain. The optimal control design problem is also considered. Finally, numerical simulation results are given to illuminate the effectiveness and practicality of the proposed design method.

Blotto 게임을 풀기위한 새로운 근사해법 절차 (New Fictitious Play Procedure For Solving Blotto Games)

  • 이재영;이문걸
    • 한국국방경영분석학회지
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    • 제31권1호
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    • pp.107-121
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    • 2005
  • In this study, a new fictitious play (FP) procedure is presented to solve two-person zero-sum (TPZS) Blotto games. The FP solution procedure solves TPZS games by assuming that the two players take turns selecting optimal responses to the opponent's strategy observed so far. It is known that FP converges to an optimal solution, and it may be the only realistic approach to solve large games. The algorithm uses dynamic programming (DP) to solve FP subproblems. Efficiency is obtained by limiting the growth of the DP state space. Blotto games are frequently used to solve simple missile defense problems. While it may be unlikely that the models presented in this paper can be used directly to solve realistic offense and defense problems, it is hoped that they will provide insight into the basic structure of optimal and near-optimal solutions to these important, large games, and provide a foundation for solution of more realistic, and more complex, problem

NFR 방식 Optical Flying Head의 형상 최적설계 (Optimal Design of Optical Flying Head for Near-Field Recording)

  • 김석훈;윤상준;최동훈;정태건;박진무;김수경
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2003년도 춘계학술대회논문집
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    • pp.1165-1169
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    • 2003
  • This paper presents an approach to optimally design the air-bearing surface (ABS) of the optical flying head for near-field recording technology (NFR). NFR is an optical recording technology using very small beam spot size by overcoming the limit of beam diffraction. One of the most Important problems in NFR is a head disk interface (HDI) issue over the recording band during the operation. A multi-criteria optimization problem is formulated to enhance the flying performances over the entire recording band during the steady state. The optimal solution of the slider, whose target flying height is 50 nm, is automatically obtained. The flying height during the steady state operation becomes closer to the target values than those fur the initial one. The pitch and roll angles are also kept within suitable ranges over the recording band. Especially, all of the air-bearing stiffness are drastically increased by the optimized geometry of the air bearing surface.

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MF-TDMA 광대역 위성시스템을 위한 QoS 기반 최적 타임슬롯 할당 체계 (QoS-based Optimal Timeslot Allocation for MF-TDMA Broadband Satellite Systems)

  • 장근녕;이기동;박유진
    • 한국경영과학회지
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    • 제29권4호
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    • pp.141-157
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    • 2004
  • In this paper, we consider broadband satellite systems using MF-TDMA(Multi-Frequency Time Division Multiple Access) scheme. First, we analyze return link, superframe structure, and QoS( Quality of Service) parameters in broadband satellite systems, and mathematically formulate the QoS-based optimal timeslot allocation problem as a nonlinear integer programming problem for broadband satellite systems with clear-sky and rain-fade satellite terminals, and multiple data classes. Next, we modify the proposed problem to solve it within in a fast time, and suggest the QoS-based optimal timeslot allocation scheme. Extensive simulation results show that the proposed scheme finds an optimal solution or a near optimal solution within 5ms at Pentium IV PC.

분지한계법을 이용한 양면조립라인 밸런싱 (Two-sided assembly line balancing using a branch-and-bound method)

  • 김여근;이태옥;신태호
    • 대한산업공학회지
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    • 제24권3호
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    • pp.417-429
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    • 1998
  • This paper considers two-sided (left and right side) assembly lines which are often used, especially in assembling large-sized products such as trucks and buses. A large number of exact algorithms and heuristics have been proposed to balance one-sided lines. However, little attention has been paid to balancing two-sided assembly lines. We present an efficient algorithm based on a branch and bound for balancing two-sided assembly lines. The algorithm involves a procedure for generating an enumeration tree. To efficiently search for the near optimal solutions to the problem, assignment rules are used in the method. New and existing bound strategies and dominance rules are else employed. The proposed algorithm can find a near optimal solution by enumerating feasible solutions partially. Extensive computational experiments are carried out to make the performance comparison between the proposed algorithm and existing ones. The computational results show that our algorithm is promising and robust in solution quality.

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불규칙 작용힘들간의 Correlation이 평판의 진동레벨에 미치는 영향 (Effects of Source Correlation on Plates Driven by Multi-point Random Forces)

  • Oh, S.G.;Park, J.D.;Kwak, C.S.
    • 한국정밀공학회지
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    • 제11권1호
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    • pp.166-176
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    • 1994
  • The problem of reducing the vibration level of elastic plates driven by multiple random point forces is analyzed in this study. First, the analytical solution for the vibration level of finite thin plates with four simply supported edges under the action of multiple random point force is derived. By assuming the plates to be lightly damped, an approximate solution for the vibration level of the plate is obtained. A numerical study is carried out to determine an optimal spacing distance between the multiple point forces in order to produce a relative minimum in the plate's vibration level. The optimal spacing distance is shown to depend on the given excitation band. The effects of wave cancellation in the near field of the multiple point forces are discussed by using the equivalence of certain stationary random responses and deterministic pulse responese.

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