1. The multilevel MINLP optimization approach to structural synthesis: the simultaneous topology, material, standard and rounded dimension optimizationStojan Kravanja, Simon Šilih, Zdravko Kravanja, 2005, izvirni znanstveni članek Opis: The paper describes the simultaneous topology, material, standard and rounded dimension optimization of mechanical structures, performed by the MixedInteger Nonlinear 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 nonconvexities, the Modified OuterApproximation/EqualityRelaxation (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: 1863; Prenosov: 78 Povezava na celotno besedilo 
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3. Mixedinteger nonlinear programming based optimal time scheduling of construction projects under nonconvex costsRok Cajzek, Uroš Klanšek, 2016, izvirni znanstveni članek Opis: Optimal project scheduling under nonconvex timecost relations represents a challenging problem in construction management. The nonconvex timecost relations may appear in a construction project when several different duration options are available for its activities due to alternative technological processes enabled for their realization or wide accessibility of production resources. The source of nonconvexity of the project scheduling optimization problem can also be the project penalty or bonusduration relations arranged within the construction contract. The aim of this paper is to present the mixedinteger nonlinear programming (MINLP) based optimal time scheduling of construction projects under nonconvex costs. For this purpose, the MINLP model was developed and applied. A numerical example from literature and an example of construction project timecost tradeoff analysis under practical nonconvex penalty function are given in the paper to demonstrate advantages of MINLP optimization. The example from literature first presented the capability of the MINLP approach to obtain the optimal solution for difficult, highly combinatorial nonconvex discrete project scheduling problem. Thereupon, the following example revealed that the optimal project timecost curve may take very nonuniform shape on account of discrete nature of activity direct cost options and nonconvex relation between project duration and total cost. In this way, the presented study intends to provide practitioners with new information from the field of optimization techniques for project scheduling as well as an alternative view on performance of total cost when project duration is changed. Ključne besede: extreme environments, construction management, discrete optimization, mixedinteger nonlinear programming, nonconvex costs, time scheduling Objavljeno: 12.07.2017; Ogledov: 587; Prenosov: 287 Celotno besedilo (807,33 KB) Gradivo ima več datotek! Več...

4. On vulnerability measures of networksRija Erveš, Darja Rupnik Poklukar, Janez Žerovnik, 2013, objavljeni znanstveni prispevek na konferenci Opis: As links and nodes of interconnection networks are exposed to failures, one of the most important features of a practical networks design is fault tolerance. Vulnerability measures of communication networks are discussed including the connectivities, fault diameters, and measures based on Hosoya Wiener polynomial. An upper bound for the edge fault diameter of product graphs is proved. Ključne besede: discrete optimization, communication network, vulnerability Objavljeno: 21.07.2017; Ogledov: 435; Prenosov: 75 Celotno besedilo (189,03 KB) Gradivo ima več datotek! Več...

5. Discrete optimization with fuzzy constraintsPrimož Jelušič, Bojan Žlender, 2017, izvirni znanstveni članek Opis: The primary benefit of fuzzy systems theory is to approximate system behavior where analytic functions or numerical relations do not exist. In this paper, heuristic fuzzy rules were used with the intention of improving the performance of optimization models, introducing experiential rules acquired from experts and utilizing recommendations. The aim of this paper was to define soft constraints using an adaptive networkbased fuzzy inference system (ANFIS). This newlydeveloped soft constraint was applied to discrete optimization for obtaining optimal solutions. Even though the computational model is based on advanced computational technologies including fuzzy logic, neural networks and discrete optimization, it can be used to solve realworld problems of great interest for design engineers. The proposed computational model was used to find the minimum weight solutions for simplysupported laterallyrestrained beams. Ključne besede: uncertainty, discrete optimization, neurofuzzy technique, structural optimization Objavljeno: 09.08.2017; Ogledov: 622; Prenosov: 267 Celotno besedilo (1,10 MB) Gradivo ima več datotek! Več...
