Fernando Rubio

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Finding the optimal solution to NP-hard problems requires at least exponential time. Thus, heuristic methods are usually applied to obtain acceptable solutions to this kind of problems. In this paper we propose a new type of heuristic algorithms to solve this kind of complex problems. Our algorithm is based on river formation dynamics and provides some(More)
Estrogens have been often identified as the major contributors to the endocrine-disrupting activity observed in environmental waters. However, their analysis in these, sometimes very complex, matrices is still challenging due to the very low detection limits and the selectivity required for their reliable determination at the very low concentrations at(More)
This paper presents a generic formal framework to specify and test autonomous e-commerce agents. First, the formalism to represent the behavior of agents is introduced. The corresponding machinery to define how implementations can be tested follows. Two testing approaches are considered. The first of them, that can be called active, is based on stimulating(More)
We propose an instrumental method based on liquid chromatography coupled to negative ion-spray ionization (ISP(-)) tandem mass spectrometry (MS/MS), for the simultaneous analysis of eight hydroxylated brominated diphenyl ethers (OH-PBDEs) in four different environmental matrices (soil, fish, sludge and particulate matter). The reversed-phase chromatographic(More)
Many different types of auctions can be applied to determine selling prices, each of them fulfilling different properties. Among them, Vickrey auctions are specially interesting due to the fact that they disallow strategic behaviors of the bidders. In fact, the dominant strategy for each bidder consists in bidding his reserve price. However, somebody has to(More)
This paper presents a practical evaluation and comparison of three state-of-the-art parallel functional languages. The evaluation is based on implementations of three typical symbolic computation programs, with performance measured on a Beowulf-class parallel architecture. ∗This work is primarily supported by the Austrian Academy of Sciences (APART(More)