1,721,202 research outputs found
Multivariate negative aging in an exchangeable model of heterogeneity
Full text linkWe introduce an exchangeable model, which accounts for heterogeneity and dependence at a time. Based on this model, we show how situations of multivariate negative ageing arise in a natural way from conditions of heterogeneity
Simulating the tail of the interference in a Poisson network model
Full text linkInterference among simultaneous transmissions represents the main limitation factor for the capacity and connectivity of dense wireless networks. In this paper we provide efficient simulation laws for the tail of the interference in a simple wireless ad hoc network model. Particularly, we consider node locations distributed according to a Poisson point process and various classes of light-tailed fading distribution
Two-reactor system with partial phase separation for anaerobic treatment of olive oil mill effluents
No full textPrevious works on the anaerobic treatment of olive oil mill effluents (OME) have shown that the inhibition of methane production is mainly caused by the presence of lipids. Saturation of unsaturated long-chain fatty acids (LCFAs) is the key factor to prevent inhibition of methanogenesis. This paper reports the experimentation carried out in a semi-continuous lab scale two-reactor system fed with diluted OME. Phase separation (acidogenesis and methanogenesis) was not complete in the two reactors. Indeed, a moderate methanogenic activity was allowed to be established in the first reactor. This scheme proved to be suitable to obtain an almost quantitative biotransformation of unsaturated LCFAs to palmitic acid in the first reactor, thus drastically lowering lipid inhibition on methanogenesis in the second reactor. The addition of an easily biodegradable substrate such as glucose did not improve biodegradation of pol!,phenols. A continuous flushing of N-2/CO2 through the 'acidogenic' reactor did not promote the P-oxidation of palmitic acid. The two-reactor system with partial phase separation could find useful application for the anaerobic treatment of any lipid-containing wastewater. (C) 1998 Published by Elsevier Science Ltd. All rights reserved
Selected papers from the 4th workshop on European Collaboration for Higher Education and Research in Nuclear Engineering & Radiological Protection
No full textThe fourth workshop on European Collaboration for Higher Education and Research in Nuclear Engineering & Radiological Protection was held in Favignana (Sicily), May 26-28th 2008. Participants came from 7 countries presenting 30 papers, 19 of which have been collected as selected works to appear in the present special issue. As the name implies, the meeting was part of an ongoing series, representing a yearly occasion for the CHERNE network of European Universities to meet and exchange their most recent achievements in nuclear research, and develop continuously new ways of scientific collaboration.
The meeting was organised jointly by the Universities of Bologna, Catania and Messina, under the auspices and high patronage of the Regione Sicilia, the regional Government of Sicily, and in particular of the regional Superintendence for Culture and Education.
The workshop was not limited to a specific topic, but rather comprised all applications of nuclear technologies, and papers were presented on nuclear power generation systems, nuclear physics and detection, nuclear medical applications, radioisotope technologies, all representing the front end of nuclear research at the respective Institutions. The participation of non-University Institutions with scientific interest in nuclear sciences was very welcome, and scientists from ENEA (the Italian nuclear research centre) and from INFN (the Italian National Institute for Nuclear Physics) attended and presented some of their current nuclear research
Lundberg parameters for non standard risk processes
No full textWe consider risk processes with delayed claims in a Markovian environment, and we study the asymptotic behaviour of finite and infinite horizon ruin probabilities under the small claim assumption. We also consider multivariate risk processes of the same kind, and we give upper and lower bounds for the Lundberg parameters of the corresponding total reserve. Our results have strong analogies with those one in the paper by Juri (Super modular order and Lundberg exponents, 2002)
Rate of convergence to equilibrium of marked Hawkes processes
No full textIn this article we obtain rates of convergence to equilibrium of marked Hawkes processes in two situations. Firstly, the stationary process is the empty process, in which case we speak of the rate of extinction. Secondly, the stationary process is the unique stationary and nontrivial marked Hawkes process, in which case we speak of the rate of installation. The first situation models small epidemics, whereas the results in the second case are useful in deriving stopping rules for simulation algorithms of Hawkes processes with random marks
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