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Ključne besede: infinite graph, weakly median graph, geodesic topology, ray, hyperinterval
Objavljeno: 31.05.2012; Ogledov: 666; Prenosov: 13
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Opis: We give results about the dimension of continua, obtained by combining inverselimits of inverse sequences of metric spaces and one-valued bonding maps with inverse limits of inverse sequences of metric spaces and upper semicontinuous set-valued bonding functions, by standard procedure introduced in [I. Banič, Continua with kernels, Houston J. Math. (2006) in press].
Ključne besede: mathematics, topology
Objavljeno: 31.05.2012; Ogledov: 852; Prenosov: 8
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Opis: The paper presents the topology and standard sizes optimization of a single-storey industrial steel building, made from standard hot rolled I sections. The structure consists of main portal frames, connected with purlins. The structural optimization is performed by the Mixed-Integer Non-linear programming approach (MINLP). The MINLP performs a discrete topology and standard dimension optimization simultaneously with continuous parameters. Since the discrete/continuous optimization problem of the industrial building is non-convex and highly non-linear, the Modified Outer- Approximation/Equality-Relaxation (OA/ER) algorithm has been used for the optimization. Alongside the optimum structure mass, the optimum topology with the optimum number of portal frames and purlins as well as all standard cross-section sizes have been obtained. The paper includes the theoretical basis and a practical example with the results of the optimization.
Ključne besede: civil engineering, topology optimization, sizing optimization, nonlinear programming, MINLP
Objavljeno: 31.05.2012; Ogledov: 1265; Prenosov: 28
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Opis: The paper describes the simultaneous topology, material, standard and rounded dimension optimization of mechanical structures, performed by the Mixed-Integer Non-linear Programming (MINLP) approach. Beside the generation of an MINLP mechanical superstructure, the development of a general multilevel MINLP formulation for a mechanical superstructure is presented. The consideration of the discrete materials as well as standard and particularly rounded dimensions in structural synthesis significantly increases the combinatorics of the discrete optimization, which as a result may become too difficult to solve. A Linked Multilevel Hierarchical Strategy (LMHS) has been introduced for the solving of such large combinatorial problems. In order to decrease the effect of non-convexities, the Modified Outer-Approximation/Equality-Relaxation (OA/ER) algorithm has been applied. Four numerical examples of different complexities are presented to illustrate the proposed multilevel MINLP optimization approach: the optimization of two steel trusses, a composite I beam and a hydraulic steel roller gate Intake gate, erected in Aswan II, Egypt.
Ključne besede: structural optimization, structural synthesis, MINLP, topology opitmization, material optimization, discrete variable optimization, multilevel MINLP strategy, truss, composite beam, roller gate
Objavljeno: 01.06.2012; Ogledov: 1466; Prenosov: 34
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Ključne besede: mathematics, topology, continua, inverse limits, tent maps, Knaster continua
Objavljeno: 07.06.2012; Ogledov: 635; Prenosov: 22
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