Search results for "optimization"

Agent assisted interactive algorithm for computationally demanding multiobjective optimization problems

2015

Abstract We generalize the applicability of interactive methods for solving computationally demanding, that is, time-consuming, multiobjective optimization problems. For this purpose we propose a new agent assisted interactive algorithm. It employs a computationally inexpensive surrogate problem and four different agents that intelligently update the surrogate based on the preferences specified by a decision maker. In this way, we decrease the waiting times imposed on the decision maker during the interactive solution process and at the same time decrease the amount of preference information expected from the decision maker. The agent assisted algorithm is not specific to any interactive me…

Stochastic debt sustainability analysis for sovereigns and the scope for optimization modeling

2017

We argue that sovereign debt sustainability analysis must be augmented by stochastic correlated risk factors and a risk measure to capture tail effects. Crisis situations can thus be adequately specified and analyzed with sufficient accuracy to warrant the relevance of policy decisions. In this context there is significant scope for optimization modeling for both strategic planning and operational management. We discuss diverse aspects of the problem of debt sustainability and highlight modeling approaches that can be brought to bear on the problem. Results with the fictitious, but nor unrealistic, Kingdom of Atlantis, which is sinking under excessive debt, illustrate the proposed models.

Economic benefits from food recovery at the retail stage: An application to Italian food chains

2013

The food supply chain is affected by losses of products near to their expiry date or damaged by improper transportation or production defects. Such products are usually poorly attractive for the consumer in the target market even if they maintain their nutritional properties. On the other hand undernourished people face every day the problem of fulfilling their nutritional needs usually relying on non-profit organizations. In this field the food recovery enabling economic benefits for donors is nowadays seen as a coherent way to manage food products unsalable in the target market for various causes and thus destined to be discarded and disposed to landfill thus representing only a cost. Des…

The ELECTRE I method to optimise GPR data processing analyses for maintenance of water networks

2017

Management of water supply systems (WSSs) can be effectively pursued by means of data processing techniques based on Ground Penetrating Radar (GPR) image mining. This approach enables to collect different graphical representations of WSS buried elements on the basis of which planning maintenance interventions, with the objective of improving the overall condition of the system. This paper proposes to support this kind of techniques by means of a multi criteria decision making (MCDM) point of view. In particular, the ELECTRE I method is suggested to treat results coming from the application of different techniques. A real case study is applied with relation to a set of four alternatives, whi…

SELECTION OF REHABILITATION ALTERNATIVES OF WATER DISTRIBUTION SYSTEMS IN CONDITION OF LACK OF DATA BY CONCISE PERFORMANCE INDICES AND OPTIMIZATION T…

2011

Selection of rehabilitation alternatives in condition of data scarcity by concise performance indices

2011

Weak and strong convergence of an inertial proximal method for solving bilevel monotone equilibrium problems

2022

In this paper, we introduce an inertial proximal method for solving a bilevel problem involving two monotone equilibrium bifunctions in Hilbert spaces. Under suitable conditions and without any restrictive assumption on the trajectories, the weak and strong convergence of the sequence generated by the iterative method are established. Two particular cases illustrating the proposed method are thereafter discussed with respect to hierarchical minimization problems and equilibrium problems under saddle point constraint. Furthermore, a numerical example is given to demonstrate the implementability of our algorithm. The algorithm and its convergence results improve and develop previous results i…

Towards Graphical Query Notation for Semantic Databases

2015

We describe a notation and a tool for schema-enabled visual/diagrammatic creation of SPARQL queries over RDF databases. The notation and the tool support both the standard basic query pattern comprising a main query class and possibly linked condition classes and means for aggregate query definition and placing conditions over aggregates including also aggregation of aggregate results. We discuss the applicability of the tool for ad-hoc query formulation in practical use cases.

Post-search query modeling in federated web scenario

2014

As opposed to query reformulation oriented towards changes made by a user to specify the information need more precisely, a post-search query modeling is a technique of exploiting syntax variation of gradually extended query which depending on some other factors like e.g. the resource, database or the key word alignment, facilitates the searching process. The study into modeling query submitted to some search engines that utilize different translation semantic paradigms is motivated by a real-world's challenges to retrieve heterogeneous textual documents from the web. For a couple of language pairs, we develop a user-centered framework for imposing the Hidden Web traffic optimization. In li…

Feature selection: A multi-objective stochastic optimization approach

2020

The feature subset task can be cast as a multiobjective discrete optimization problem. In this work, we study the search algorithm component of a feature subset selection method. We propose an algorithm based on the threshold accepting method, extended to the multi-objective framework by an appropriate definition of the acceptance rule. The method is used in the task of identifying relevant subsets of features in a Web bot recognition problem, where automated software agents on the Web are identified by analyzing the stream of HTTP requests to a Web server.