On the Evaluation of the Asymptotic Fairness of Bonus-Malus Systems

In this paper we try to evaluate the asymptotic fairness of bonus-malus systems, assuming the simplest case when there is no hunger for bonus.The asymptotic fairness has to be understood as the bonus-malus systemability in assessing the individual risks in the long run (see Lemaire[1995] p.xvi). Firstly we de…ne the asymptotic fairness of a bonus-malussystem following an expression that can be found in Lemaire [1985] p.168. Secondly, we de…ne a measure of the global asymptotic fairness considering the structure function of the risk group. Finally we try to calculate, for each set of transition rules and a given structure function,the scale of premiums that brings the global asymptotic fairness closest to the ideal situation where each insured pays in the long run a premium corresponding to its own claim frequency. This is possible thanks to the application of a multiobjective optimization technique named Goal Programing. We give an example illustrating the fact that the ideal case could be fairly well approached.

PBC design for voltage regulation in buck converters with parametric uncertainties

This paper addresses the problem of voltage output regulation in DC Buck converters from the passivity-based control (PBC) point of view. The PBC takes advantage of the natural port-Hamiltonian representation of dynamic equations of the buck converter, to design a feedback controller with proportionalintegral gains, that allows to guarantee stability conditions in the sense of Lyapunov for closed-loop operation. The design of the controller is based on the incremental dynamic model of the buck converter. The PBC approach considers unknown resistive loads in the controller design without degrading the dynamic performance of the controller. In addition, the proposed approach allows to design a controller regardless the buck parameters (capacitance and inductance) which makes it robust to parametric uncertainties. Sliding planes and classical PI control methods are used for comparing the proposed PBC method. All simulations have been performed in MATLAB software by using SymPowerSystems library

Air-steam gasification of char derived from sewage sludge pyrolysis. Comparison with the gasification of sewage sludge

Air-steam gasification of char derived from fast pyrolysis of sewage sludge has been experimentally evaluated in a fluidized bed as a route towards a full recovery of energy from sewage sludge. The results have been compared with those obtained from the direct gasification of sewage sludge in order to evaluate how the previous pyrolysis stage affects the subsequent gasification process. The fixed carbon content in the solid increased after the pyrolysis stage so that heterogeneous reactions of carbon with steam or CO2 assumed greater importance during char gasification than during sewage sludge gasification. Furthermore, char gasification led to an improvement in the gas yield -calculated on a dry and ash-free basis (daf)- due to the increased concentration of carbon in the organic fraction of the solid after the pyrolysis step, with an increase in the average CO yield of about 70% -in terms of g/kg solid daf-. The reduction in the fraction of carbon which forms tar is another advantage of char gasification over the direct gasification of sewage sludge, with an average decrease of about 45%. Regarding the influence of the operating conditions, the response variables were mainly controlled by the same factors in both processes

Air-steam gasification of sewage sludge in a fluidized bed. Influence of some operating conditions

An experimental work was carried out to investigate the viability of energy recovery from the air–steam gasification of sewage sludge. The relative influence of different factors, as well as the effect of their possible interactions, has been determined by means of analysis of variance. Temperature was found to be the most influential factor for most of the variables analyzed. Solid yield (35–41 wt.%) and tar content (11–45 g/m3 STP) were largely reduced with temperature, whereas gas production (0:89 -- 1:32 m3 STP/kg sewage sludge dry and ash free), carbon yield to gas phase (62–90 wt.%), gasification efficiency (39–66%), and H2 and CO yields (20–52 and 137–414 g/kg sewage sludge dry and ash free, respectively) were improved at high temperature. Other important parameters for the end-use of the gas such as its heating value (4.12–6.20 MJ/m3 STP) and its H2/CO molar ratio (1.46–3.25) were greatly influenced by the composition of the gasification medium, since the increase in the steam to oxygen ratio was favorable for both. The comparison of experimental and theoretical results highlights that equilibrium was not reached during the experimental run

Fisheries and reproductive biology of Octopus vulgaris (Mollusca: Cephalopoda) in the Gulf of Alicante (Northwestern Mediterranean)

The common octopus Octopus vulgarisCuvier, 1797 is the most fished cephalopod species along the Spanish coasts. Its catches are highly fluctuating due to the short life cycle of the species and to the annual variability of the recruitment pattern, strongly dependent on the environmental conditions affecting the eggs and paralarvae. This study examines the common octopus fishery, the catch composition, and the main features of the reproductive biology of this species in the Gulf of Alicante (Spanish Eastern coast, Western Mediterranean FAO division 37.1.1). The common octopus fishery was studied analysing the monthly landing and effort data by fishing gear from 1994 to 2005. Monthly samplings of the commercial O. vulgarislandings from trawlers and clay pots from January 2004 to December 2005 resulted in the measuring of 1833 specimens to enable analysis of the catch composition, and allowed the biological sampling of 1176 individuals to provide the reproductive parameters of the species in the study area. The length-weight relationship calculated for the species was BW = 0.51 * DML 2.87. The yearly sex ratios (males:females) were 1:1 (trawl, 2004), 1:0.74 (trawl, 2005), and 1:0.88 (clay pots, 2005). The size (dorsal mantle length, DML) at maturity of the species in the study area was 9.67 cm for males and 14.38 cm for females. The gonadosomatic index reached a peak between April and July for males and in July for females. The Fulton condition index was lower in both sexes between June and September, and for males in November-December, whereas for both sexes the values of the digestive gland index were at their maximum between June and December. The energy allocation between somatic and reproductive growth was investigated and the results suggested that the energy spent on reproduction mainly came from feeding, and not from energy stored in the mantle tissues or in the digestive glan

On the presence of Heterocarpus ensifer Milne Edwards, 1881 (Decapoda, Pandalidae) in the Spanish Mediterranean

Not

Ganado de doble propósito en El Nus

El nombre Ganado de Doble Propósito solo se ha difundido en las ultimas décadas; es tan antiguo como la domesticación de los bovinos porque de ellos se ha extraído leche y carne simultáneamente. Aproximadamente en 1977 el Instituto Colombiano Agropecuario (ICA) inicia la elaboración del Proyecto de Ganado de Doble propósito, considerando, entre otros, dos aspectos muy importantes: 1. La organización Mundial de la Salud y el Instituto Colombiano de Bienestar Familiar, recomiendan 140 litros de leche por persona por afio y escasamente se llega a un consumo de 70 litros. Estas organizaciones aconsejan consumir 70 kilogramos de carne por persona por afio y solamente se llega a unos 25 kilogramos.Ganado de doble propósito-Ganaderia doble proposit