Search results for "OPTIMA"
showing 10 items of 735 documents
Predictors of tourist engagement: Travel motives and tourism destination profiles
2020
Abstract The aim of this study is to investigate the influence of travel motives and regional tourism destinations on positive/negative engagement with a destination management organisation (DMO). According to previous literature, travel motives were classified as push and pull motives, and regional tourism destinations were classified by tourist demand behaviour. To achieve the objective, the totality of posts about regional tourism destinations published on the Brand Spain's Official Facebook Fanpage during a year were analysed (418), along with audience reactions (127,750), comments (3219) and shares to such posts. A content analysis was performed, with a regression analysis (optimal sca…
An empirical analysis of online price dispersion in the Italian airline industry
2015
Firms operating in the electronic marketplace set and adjust prices to affect demand and profitability. In service markets, such as airline markets, different prices are commonly offered by diverse firms to accommodate to a variety of market segments having particular sets of consumer attitudes. This variation in prices is the price dispersion and is based on market distinctiveness deriving from customer heterogeneity as well as the peculiar competition in the specific market arena. In this paper we use a panel dataset from the Italian airline market to investigate the role of competition and different online channels in the emergence of price dispersion. Specifically, we examine the unclea…
Constructing a Pareto front approximation for decision making
2011
An approach to constructing a Pareto front approximation to computationally expensive multiobjective optimization problems is developed. The approximation is constructed as a sub-complex of a Delaunay triangulation of a finite set of Pareto optimal outcomes to the problem. The approach is based on the concept of inherent nondominance. Rules for checking the inherent nondominance of complexes are developed and applying the rules is demonstrated with examples. The quality of the approximation is quantified with error estimates. Due to its properties, the Pareto front approximation works as a surrogate to the original problem for decision making with interactive methods. Qc 20120127
LRPH device optimization for axial and shear stresses
2020
The paper concerns an in-depth study of a special connection for steel structures and the formulation of the related optimal design problem. The connection is called Limited Resistance Rigid Perfectly Plastic Hinge (LRPH) and it represents an innovative device devoted to join steel beam elements of frame structures. The device consists in a sequence of steel cross sections constituted by two parallel flanges with suitably different thickness connected by as many webs with constant and equal thickness. The fundamental innovation of the device is the possibility of designing special connections with elastic stiffness and limit strength independent of each other. Such a special characteristic …
Optimal control circuitry design for the digital p53 dynamics in cancer cell and apoptosis
2009
AbstractExperimental work and theoretical models deduce a "digital" response of the p53 transcription factor when genomic integrity is damaged. The mutual influence of p53 and its antagonist, the Mdm2 oncogene, is closed in feedback. This paper proposes an aerospace architecture for translating the p53/Mdm2/DNA damage network into a digital circuitry in which the optimal control theory is applied for obtaining the requested dynamic evolutions of some considered cell species for repairing a DNA damage. The purpose of this paper is not to improve the analysis of the actual mathematical models but to demonstrate the usefulness of such digital circuitry design capable to predict and detect the …
Interactive Multiobjective Robust Optimization with NIMBUS
2018
In this paper, we introduce the MuRO-NIMBUS method for solving multiobjective optimization problems with uncertain parameters. The concept of set-based minmax robust Pareto optimality is utilized to tackle the uncertainty in the problems. We separate the solution process into two stages: the pre-decision making stage and the decision making stage. We consider the decision maker’s preferences in the nominal case, i.e., with the most typical or undisturbed values of the uncertain parameters. At the same time, the decision maker is informed about the objective function values in the worst case to support her/him to make an informed decision. To help the decision maker to understand the behavio…
Shaping communities of local optima by perturbation strength
2017
Recent work discovered that fitness landscapes induced by Iterated Local Search (ILS) may consist of multiple clusters, denoted as funnels or communities of local optima. Such studies exist only for perturbation operators (kicks) with low strength. We examine how different strengths of the ILS perturbation operator affect the number and size of clusters. We present an empirical study based on local optima networks from NK fitness landscapes. Our results show that a properly selected perturbation strength can help overcome the effect of ILS getting trapped in clusters of local optima. This has implications for designing effective ILS approaches in practice, where traditionally only small per…
A Simple Indicator Based Evolutionary Algorithm for Set-Based Minmax Robustness
2018
For multiobjective optimization problems with uncertain parameters in the objective functions, different variants of minmax robustness concepts have been defined in the literature. The idea of minmax robustness is to optimize in the worst case such that the solutions have the best objective function values even when the worst case happens. However, the computation of the minmax robust Pareto optimal solutions remains challenging. This paper proposes a simple indicator based evolutionary algorithm for robustness (SIBEA-R) to address this challenge by computing a set of non-dominated set-based minmax robust solutions. In SIBEA-R, we consider the set of objective function values in the worst c…
A Proximal Solution for a Class of Extended Minimax Location Problem
2005
We propose a proximal approach for solving a wide class of minimax location problems which in particular contains the round trip location problem. We show that a suitable reformulation of the problem allows to construct a Fenchel duality scheme the primal-dual optimality conditions of which can be solved by a proximal algorithm. This approach permits to solve problems for which distances are measured by mixed norms or gauges and to handle a large variety of convex constraints. Several numerical results are presented.
A fuzzy-logic based evolutionary multiobjective approach for automated distribution networks management
2004
In this paper, a methodology to treat constrained scheduling problems based on the repeated application of a fuzzy-logic-based multiobjective algorithm is presented. The application domain is that of automated distribution systems management. In particular, the problem of voltage regulation and power loses minimization is here considered. The classical formulation of the problem of optimal control of shunt capacitor banks and under load tap changers, ULTC, located at high voltage/medium voltage (HV/MV) substations has been coupled with the optimal control of tie-switches and capacitor banks on the feeders of a large radially operated meshed distribution system with the aim of attaining mini…