80 research outputs found
A genetic algorithm to design satellite constellations for regional coverage
No full textIn this paper we propose a meta-heuristic approach to cope with the satellite constellation design for the telecommunication coverage in limited areas (region coverage). A genetic algorithm, supported by a simulation model and a local search optimisation algorithm, generates non-binary chromosomes, each one representing a constellation with a given coverage and a given number of satellites. The algorithm, following a two-objective strategy, attempts to determine Pareto-optimal constellations with respect to minimum number of satellites and region maximal coverage. The algorithm performance has been tested by evaluating optimal satellite configurations both for global coverage and for the regional ones and an extensive series of computational tests has been performed in order to validate the meta-heuristic approach proposed for regional coverage
An Economic Index of Riskiness
No full textDefine the riskiness of a gamble as the reciprocal of the absolute risk aversion (ARA) of an individual with constant ARA who is indifferent between taking and not taking that gamble. We characterize this index by axioms, chief among them a "duality" axiom which, roughly speaking, asserts that less risk-averse individuals accept riskier gambles. The index is homogeneous of degree 1, monotonic with respect to first and second order stochastic dominance, and for gambles with normal distributions, is half of variance/mean. Examples are calculated, additional properties derived, and the index is compared with others in the literature.Riskiness; Risk Aversion; Expected Utility; Decision Making under Uncertainty; Portfolio Choice; Sharpe Ratio; Variance-Mean Ratio; Value at Risk
Chronic Myelomonocytic Leukemia: Clinical Data, Morphological Features, and Outcome in 56 Patients
No full text
Monge sequences and a simple assignment algorithm
No full textAbstractIn 1781 the French mathematician G. Monge gave an optimality criterion and a greedy-like procedure for solving specially structured transportation problems. Here we present a ‘new’ approach for solving assignment problems which builts upon Monge's observation. The basic idea is to transform an arbitrary assignment problem into an ‘equivalent’ one where Monge's condition is fulfilled
Traffic sensor location and Origin/Destination matrix estimation
No full textSelected papers of the Symposium on Operations Research, Jena, September 199
Restraining public health expenditure
No full textHalth Expenditure in undoubtedly one of mail components of public expenditure in Italy. The aim of this paper is to show how the performances of institutions providing health services differ in different Italian regions and to find some economic explanation of this situation. empirical estimates verify the existence of a significant correlation between the amount of free health service suplied and their demand. this evidence seems indicate thet the private expenditure will not substitute completely reduced public spending
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