• 제목/요약/키워드: method of feasible directions

검색결과 33건 처리시간 0.022초

A GLOBALLY AND SUPERLIEARLY CONVERGENT FEASIBLE SQP ALGORITHM FOR DEGENERATE CONSTRAINED OPTIMIZATION

  • Chen, Yu;Xie, Xiao-Liang
    • Journal of applied mathematics & informatics
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    • 제28권3_4호
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    • pp.823-835
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    • 2010
  • In this paper, A FSQP algorithm for degenerate inequality constraints optimization problems is proposed. At each iteration of the proposed algorithm, a feasible direction of descent is obtained by solving a quadratic programming subproblem. To overcome the Maratos effect, a higher-order correction direction is obtained by solving another quadratic programming subproblem. The algorithm is proved to be globally convergent and superlinearly convergent under some mild conditions. Finally, some preliminary numerical results are reported.

선형계산문제의 비정변형해법의 연구 (A Non-edge Following Method for Solving Linear Programs)

  • 백승규;안병훈
    • 한국경영과학회지
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    • 제6권2호
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    • pp.25-34
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    • 1981
  • In this paper, we propose a non-edge following method for linear programs. Unlike alledged poor performance of algorithms of this type, this method performs well at least with 25 randomly generated problems. This method is comparable to Rosen's gradient projection method as applied to the dual formulation. The latter is of general purpose, and no implementation rules are available for linear program applications. This paper suggests ways of finding improving dual feasible directions, and of allowing to move across the extreme faces of a higher dimension polyhedron. Rather simple computational rules are provided for projection operations needed at each iteration.

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다변환 심플렉스 기법과 이의 효율성 (A Multi-interchange Simplex Method and its Computational Efficiency)

  • 정성진;이면우;이창훈;강석호
    • 한국국방경영분석학회지
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    • 제11권1호
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    • pp.79-86
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    • 1985
  • A multi-interchange simplex method is presented. This method tries to cut almost half of the set of convex combinations which generate all decreasing feasible directions. Analysis of this method indicates high possibility of the existence of polynomial-time simplex-type methods.

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Optimization of structural and mechanical engineering problems using the enriched ViS-BLAST method

  • Dizangian, Babak;Ghasemi, Mohammad Reza
    • Structural Engineering and Mechanics
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    • 제77권5호
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    • pp.613-626
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    • 2021
  • In this paper, an enhanced Violation-based Sensitivity analysis and Border-Line Adaptive Sliding Technique (ViS-BLAST) will be utilized for optimization of some well-known structural and mechanical engineering problems. ViS-BLAST has already been introduced by the authors for solving truss optimization problems. For those problems, this method showed a satisfactory enactment both in speed and efficiency. The Enriched ViS-BLAST or EVB is introduced to be vastly applicable to any solvable constrained optimization problem without any specific initialization. It uses one-directional step-wise searching technique and mostly limits exploration to the vicinity of FNF border and does not explore the entire design space. It first enters the feasible region very quickly and keeps the feasibility of solutions. For doing this important, EVB groups variables for specifying the desired searching directions in order to moving toward best solutions out or inside feasible domains. EVB was employed for solving seven numerical engineering design problems. Results show that for problems with tiny or even complex feasible regions with a larger number of highly non-linear constraints, EVB has a better performance compared to some records in the literature. This dominance was evaluated in terms of the feasibility of solutions, the quality of optimum objective values found and the total number of function evaluations performed.

SHORTEST PATH FOR ROBOT CAR

  • 김제성;이상복
    • 한국국방경영분석학회지
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    • 제18권2호
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    • pp.140-150
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    • 1992
  • In this paper, we consider the shortest path problem of a Robot car moving in a workspace which consists of some obstacles. The motion of the Robot car is considered to have initial and final directions with some restrictions in the curvature of the path. At first we consider the problem in the case of having no obstacles and we give an analytical solution. Then wre present an algorithm to find a feasible path in the case of having obstacles and a method to improve this feasible path into a minimal path. Some computational results using Graph theory and Linear programming have been included.

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병렬연산을 이용한 익형의 최적 설계 (The Optimum Design of Airfoil Shape with Parallel Computation)

  • 조장근;박원규
    • 한국항공우주학회지
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    • 제31권1호
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    • pp.1-7
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    • 2003
  • 익형에 대한 공력 최적설계 프로그램을 개발하였으며, 점성 유동장에 대한 보다 정확한 정보를 설계에 반영하기 위하여 나비어-스톡스 방정식을 사용하였다. 최적설계 방법으로는 민감도 해석을 위하여 수정유용방향탐색방법(Modified Method of Feasible Directions, MMFD)을 사용하였으며 이동거리 계산을 위하여 다항식 보간법을 사용하였다. 또한 설계시간을 단축하기 위하여 MPI를 사용하여 병렬화하였다. 전체 유동장을 8개의 영역으로 분할하였으며 분할된 영역은 지정된 프로세서에 할당하여 계산을 수행하였다. 민감도 계산을 위하여 각 프로세서에 할당하여 계산을 수행하였다. 민감도 계산을 위하여 각 프로세서에 각 탐색방향을 할당하여 민감도를 병렬계산하였다. 본 연구의 수행 결과 양력은 허용한도 내의 일정한 값을 유지하는 가운데 항력이 감소된 최적화된 익형의 형상을 설계할 수 있었다.

On Application of Optimization Scheme To Direct Numerical Analysis Of Slider

  • Hwang, Pyung;Khan, Polina;Pan, Galina
    • KSTLE International Journal
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    • 제5권1호
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    • pp.23-27
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    • 2004
  • The object of the present work is the numerical analysis of the computer hard disk slider. The pressure between slider and disk surfaces is calculated using the Boundary Fitted Coordinate System and Divergence Formulation for the nonlinear Reynolds' equation solution. The optimization scheme is applied to search for the steady state position of the slider. The simplified method is given for the case of the fixed inclined pad. The film thickness ratios and pitching and rolling angles are considered as alternative choice of the slider's coordinates. The behavior of the objective function for the Negative Pressure slider is studied in details. Methods of conjugate directions and feasible directions are applied.

Task Scheduling in Fog Computing - Classification, Review, Challenges and Future Directions

  • Alsadie, Deafallah
    • International Journal of Computer Science & Network Security
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    • 제22권4호
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    • pp.89-100
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    • 2022
  • With the advancement in the Internet of things Technology (IoT) cloud computing, billions of physical devices have been interconnected for sharing and collecting data in different applications. Despite many advancements, some latency - specific application in the real world is not feasible due to existing constraints of IoT devices and distance between cloud and IoT devices. In order to address issues of latency sensitive applications, fog computing has been developed that involves the availability of computing and storage resources at the edge of the network near the IoT devices. However, fog computing suffers from many limitations such as heterogeneity, storage capabilities, processing capability, memory limitations etc. Therefore, it requires an adequate task scheduling method for utilizing computing resources optimally at the fog layer. This work presents a comprehensive review of different task scheduling methods in fog computing. It analyses different task scheduling methods developed for a fog computing environment in multiple dimensions and compares them to highlight the advantages and disadvantages of methods. Finally, it presents promising research directions for fellow researchers in the fog computing environment.

자동차 휠 베어링 유닛의 장수명 설계 (A Design of an Automotive Wheel Bearing Unit for Long Life)

  • 윤기찬;최동훈
    • 대한기계학회논문집A
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    • 제24권2호
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    • pp.319-328
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    • 2000
  • This paper presents a new design method of the 1 generation wheel bearing unit using a numerical optimization technique in order to increase bearing fatigue life. For calculating the fatigue life, a method of load analysis is studied on the automotive wheel bearing system. The design variables selected are ball size, initial contact angle, number of balls, pitch diameter, pre-load, and distance between ball centers. The method of feasible directions in ADS (Automated Design Synthesis) is utilized to automatically find the optimum design variables. To validate the design method, a computer program is developed and applied to a practical passenger car model. The optimum design results demonstrated the effectiveness of the proposed design method showing that the system life of the optimally designed wheel bearing unit is enhanced in comparison with that of the initial ones within the given available design space.

The Role of S-Shape Mapping Functions in the SIMP Approach for Topology Optimization

  • Yoon, Gil-Ho;Kim, Yoon-Young
    • Journal of Mechanical Science and Technology
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    • 제17권10호
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    • pp.1496-1506
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    • 2003
  • The SIMP (solid isotropic material with penalization) approach is perhaps the most popular density variable relaxation method in topology optimization. This method has been very successful in many applications, but the optimization solution convergence can be improved when new variables, not the direct density variables, are used as the design variables. In this work, we newly propose S-shape functions mapping the original density variables nonlinearly to new design variables. The main role of S-shape function is to push intermediate densities to either lower or upper bounds. In particular, this method works well with nonlinear mathematical programming methods. A method of feasible directions is chosen as a nonlinear mathematical programming method in order to show the effects of the S-shape scaling function on the solution convergence.