7 results
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2. New developments in the radial basis functions analysis of composite shells
- Author
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Roque, C.M.C. and Ferreira, A.J.M.
- Subjects
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MATHEMATICAL optimization , *MATHEMATICAL analysis , *MATHEMATICS , *MAXIMA & minima , *OPERATIONS research - Abstract
Abstract: In this paper, we use the third order shear deformation theory of Reddy [Reddy JN. Mechanics of laminated composite plates and shells. CRC Press; 2004] with a meshless numerical method to analyze the static deformation of composite plates and shells. Numerical results are compared with Navier solutions in various examples. The meshless collocation method based on radial basis functions requires a user-defined shape parameter than can compromise the quality of the solution when poorly chosen. To improve the choice of this shape parameter, we apply an optimization technique based on the leave-one-out cross validation analysis to obtain the shape parameter in a given interval. The results obtained were significantly better than those produced with a user-defined shape parameter. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
3. Research on integrated optimization design of hypersonic cruise vehicle
- Author
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Che, Jing and Tang, Shuo
- Subjects
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MATHEMATICAL optimization , *MATHEMATICAL analysis , *MATHEMATICS , *MAXIMA & minima , *OPERATIONS research , *SIMULATION methods & models , *INDUSTRIAL efficiency - Abstract
Abstract: Optimization design is the most important key technique of Air-breathing Hypersonic Cruise Vehicle (HCV). To improve the design level and get better integrated performances of HCV, this paper researches the integrated optimization design method of waverider hypersonic cruise vehicle. In the optimization design, Multi-Objective Genetic Algorithms (MOGA) is selected as the optimization algorithm, and the shape parameters of aircraft are as design variables. Some performances, such as aerodynamics, aeroheating, radar cross section (RCS), airframe/scramjet integration, and volume of airframe, trimmed characteristic, static stability and maneuverability at cruise phase are selected as the objectives. When the optimization process finishes, the Pareto front side is got, in which many Pareto solutions whose integrated performances are more excellent than basic configuration are found. According to the design idea, we choose a Pareto solution from the Pareto front side as the recommended shape configuration for further research. To validate the aerodynamics of recommended configuration, wind tunnel test is done. And the comparison results show that the optimization design is successful. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
4. NATURE INSPIRED INTELLIGENCE IN MEDICINE:: ANT COLONY OPTIMIZATION FOR PAP-SMEAR DIAGNOSIS.
- Author
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MARINAKIS, YANNIS and DOUNIAS, GEORGIOS
- Subjects
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MATHEMATICAL optimization , *MATHEMATICAL analysis , *MATHEMATICS , *PROBLEM solving , *MAXIMA & minima , *OPERATIONS research - Abstract
During the last years nature inspired intelligent techniques have become attractive for analyzing large data sets and solving complex optimization problems. In this paper, one of the most interesting of them, the Ant Colony Optimization (ACO), is used for the construction of a hybrid algorithmic scheme which effectively handles the Pap Smear Cell classification problem. This algorithmic approach is properly combined with a number of nearest neighbor based approaches for performing the requested classification task, through the solution of the so-called optimal feature subset selection problem. The proposed complete algorithmic scheme is tested in two sets of data. The first one consists of 917 images of pap smear cells and the second set consists of 500 images, classified carefully by expert cyto-technicians and doctors. Each cell is described by 20 numerical features, and the cells fall into seven (7) classes, four (4) representing normal cells and three (3) abnormal cases. Nevertheless, from the medical diagnosis viewpoint, a minimum requirement corresponds to the general two-class problem of correct separation between normal from abnormal cells. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
5. Multicriteria Approach to Bilevel Optimization.
- Author
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FLIEGE, J. and VICENTE, L. N.
- Subjects
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MATHEMATICAL optimization , *MATHEMATICAL analysis , *MATHEMATICS , *MAXIMA & minima , *OPERATIONS research , *SIMULATION methods & models , *CONES , *MATHEMATICAL variables , *NONCONVEX programming - Abstract
In this paper, we study the relationship between bilevel optimization and multicriteria optimization. Given a bilevel optimization problem, we introduce an order relation such that the optimal solutions of the bilevel problem are the nondominated points with respect to the order relation. In the case where the lower-level problem of the bilevel optimization problem is convex and continuously differentiable in the lower-level variables, this order relation is equivalent to a second, more tractable order relation. Then, we show how to construct a (nonconvex) cone for which we can prove that the nondominated points with respect to the order relation induced by the cone are also nondominated points with respect to any of the two order relations mentioned before. We comment also on the practical and computational implications of our approach. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
6. Generalized Motzkin Theorems of the Alternative and Vector Optimization Problems.
- Author
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ZENG, R. and CARON, R. J.
- Subjects
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MATHEMATICAL optimization , *INTEGRAL theorems , *VECTOR spaces , *MATHEMATICAL analysis , *MATHEMATICS , *MAXIMA & minima , *OPERATIONS research , *CONVEX domains , *VECTOR analysis - Abstract
In this paper, we introduce a definition of generalized convexlike functions (preconvexlike functions). Then, under the weakened convexity, we study vector optimization problems in Hausdorff topological linear spaces. We establish some generalized Motzkin theorems of the alternative. By use of these theorems of the alternative, we obtain some Lagrangian multiplier theorems. A saddle-point theorem and a scalarization theorem are also derived. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
7. A Hamiltonian-based solution to the mixed sensitivity optimization problem for stable pseudorational plants
- Author
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Kashima, Kenji, Özbay, Hitay, and Yamamoto, Yutaka
- Subjects
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MATHEMATICAL optimization , *MATHEMATICAL analysis , *MATHEMATICS , *MAXIMA & minima , *OPERATIONS research - Abstract
Abstract: This paper considers the mixed sensitivity optimization problem for a class of infinite-dimensional stable plants. This problem is reducible to a two- or one-block control problem with structured weighting functions. We first show that these weighting functions violate the genericity assumptions of existing Hamiltonian-based solutions such as the well-known Zhou–Khargonekar formula. Then, we derive a new closed form formula for the computation of the optimal performance level, when the underlying plant structure is specified by a pseudorational transfer function. [Copyright &y& Elsevier]
- Published
- 2005
- Full Text
- View/download PDF
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