1,721,020 research outputs found
The stack loading and unloading problem
No full textWhen piling a set of items in a single stack, one often does not pay attention to the order. Real-life experience suggests that, whenever a specific item is suddenly requested, we need to dig very deep into the stack to extract it.In this paper we investigate stack reordering strategies aiming at minimizing the number of "pop" and "push" operations. In particular we focus on three versions of the problem in which reordering can take place in different phases: when unloading the stack, when loading it or in both phases.We show that the first two variants can be solved in linear time, while for the third one we devise a dynamic programming method with quadratic complexity
Lower bounds for the quadratic semi-assignment problem
No full textIn this paper we will present class of new lower bounds for the Quadratic Semi-Assignment Problem (QSAP). These bounds are based on recent results about polynomially solvable cases, in particular we will consider the QSAP's whose quadratic cost coefficients define a reducible graph. Several lower bounds will be computationally compared, moreover we will present a method which improves these bounds by means of Lagrangean decomposition
Un modello per la gestione del teleriscaldamento e la cogenerazione di energia elettrica nella ciita' di Ferrara
No full textAn Optimized parallel admittance matrix approach using the adjacence-graph recursive-thresholding technique
No full textOptimal Operations Management and Network Planning of a District Heating System with a Combined Heat and Power Plant
Full text linkDistrict heating plants are becoming more common in European cities. These systems make it possible to furnish users with warm water while locating the production plants in the outskirts having the double benefit of lowering the impact of pollution on the center of the city and achieving better conversion performances. In order to amortize the costs throughout the year, the system often includes a combined heat and power (CHP) plant, to exploit the energy during the summer as well, when the demand for warm water decreases. A linear programming model for the optimal resource management of such a plant is presented and some results for a real case are reported. A distribution network design problem is also addressed and solved by means of mixed integer linear programming
Towards designing flexible transportation system
No full texthttp://transp-or2.epfl.ch/tristan/FullPapers/134Errico.pd
A particular vehicle routing problem arising in the collection and disposal of special waste
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