A Duality Procedure to Elicit Nonlinear Multiattribute Utility Functions.

The practical implementation of the Multiattribute Utility Theory is limited, partly for the lack of operative methods to elicit the parameters of the Multiattribute Utility Function, particularly when this function is not linear. As a consequence, most studies are restricted to linear specifications, which are easier to estimate and to interpret. We propose an indirect method to elicit the parameters of a nonlinear utility function to be compatible with the actual behaviour of decision makers, rather than with their answers to direct surveys. The idea rests on approaching the parameter estimation problem as a dual of the decision problem and making the observed decisions to be compatible with a rational decision making process.Multiple-Criteria Analysis, Multi-Attribute Utility Function, Simulation, Agriculture.

Schur complements in Krein spaces

The aim of this work is to generalize the notions of Schur complements and shorted operators to Krein spaces. Given a (bounded) J-selfadjoint operator A (with the unique factorization property) acting on a Krein space H and a suitable closed subspace S of H, the Schur complement A/[s]of A to S is defined. The basic properties of A/ are developed and different characterizations are given, most of them resembling those of the shorted of (bounded) positive operators on a Hilbert space.Fil: Maestripieri, Alejandra Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Matemáticas; ArgentinaFil: Martinez Peria, Francisco Dardo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentin

Statistics of the fractional polarisation of compact radio sources in Planck maps

In this work we apply the stacking technique to estimate the average fractional polarisation from 30 to 353 GHz of a primary sample of 1560 compact sources - essentially all radio sources - detected in the 30 GHz Planck all-sky map and listed in the second version of the Planck Catalogue of Compact Sources (PCCS2). We divide our primary sample in two subsamples according to whether the sources lay (679 sources) or not (881 sources) inside the sky region defined by the Planck Galactic mask (fsky ~ 60 per cent) and the area around the Magellanic Clouds. We find that the average fractional polarisation of compact sources is approximately constant (with frequency) in both samples (with a weighted mean over all the channels of 3.08 per cent outside and 3.54 per cent inside the Planck mask). In the sky region outside the adopted mask, we also estimate the {\mu} and {\sigma} parameters for the log-normal distribution of the fractional polarisation, finding a weighted mean value over all the Planck frequency range of 1.0 for {\sigma} and 0.7 for {\mu} (that would imply a weighted mean value for the median fractional polarisation of 1.9 per cent).Comment: 12 pages, 7 figures, 2 tables, MNRAS in pres

Using a modified DEA model to estimate the importance of objectives. An application to agricultural economics.

This paper shows a connection between Data Envelopment Analysis (DEA) and the methodology proposed by Sumpsi et al. (1997) to estimate the weights of objectives for decision makers in a multiple attribute approach. This connection gives rise to a modified DEA model that allows to estimate not only efficiency measures but also preference weights by radially projecting each unit onto a linear combination of the elements of the payoff matrix (which is obtained by standard multicriteria methods). For users of Multiple Attribute Decision Analysis the basic contribution of this paper is a new interpretation of the methodology by Sumpsi et al. (1997) in terms of efficiency. We also propose a modified procedure to calculate an efficient payoff matrix and a procedure to estimate weights through a radial projection rather than a distance minimization. For DEA users, we provide a modified DEA procedure to calculate preference weights and efficiency measures which does not depend on any observations in the dataset. This methodology has been applied to an agricultural case study in Spain.Multicriteria Decision Making, Goal Programming, Weights, Preferences, Data Envelopment Analysis.

Educational Reform and Labor Market Outcomes: the Case of Argentina's Ley Federal de Educacion

In the nineties Argentina implemented a large education reform (Ley Federal de Educación – LFE) that mainly implied the extension of compulsory education in two additional years. The timing in the implementation substantially varied across provinces, providing a source of identification for unraveling the causal effect of the reform. The estimations from difference-in-difference models suggest that the LFE had an overall positive although mild impact on education and labor outcomes. The impact on the income-deprived youths was small for education outcomes and null for labor outcomes.Education, reform, labor market, wages, employment, Argentina

Using DEA to estimate the importance of objectives for decision makers

In this paper we establish further connections between DEA and Multi-criteria Decision Analysis by suggesting a particular way to estimate preference weights for different objectives using DEA. We claim that the virtual multipliers obtained from a standard DEA model are not suitable to measure the preferences of a decision maker. Our suggestion takes advantage of the parallelism between DEA and the methodology proposed by Sumpsi et al. (1997) by projecting each unit on a linear combination of the elements of the pay-off matrix. Finally, we make an application of the proposed methodology to agricultural economics in a case study with Spanish data.Data Envelopment Analysis, Multicriteria Decision Analysis, preferences, weights, virtual multipliers.

An Economic, Energy, and Environmental Analysis of PV/Micro-CHP Hybrid Systems: A Case Study of a Tertiary Building

Our present standard of living depends strongly on energy sources, with buildings being a primary focus when it comes to reducing energy consumption due to their large contribution, especially in tertiary buildings. The goal of the present study is to evaluate the performance of two different designs of hybrid systems, composed of natural gas engines and photovoltaic panels. This will be done through simulations in TRNSYS, considering a representative office building with various schedules of operation (8, 12, and 24 h), as well as different climates in Spain. The main contributions of this paper are the evaluations of primary energy-consumption, emissions, and economic analyses for each scenario. In addition, a sensitivity analysis is carried out to observe the influence of energy prices, as well as that of the costs of the micro-CHP engines and PV modules. The results show that the scenario with the conventional system and PV modules is the most profitable one currently. However, if electricity prices are increased in the future or natural gas prices are reduced, the scenario with micro-CHP engines and PV modules will become the most profitable option. Energy service engineers, regulators, and manufacturers are the most interested in these results

Resistencia al nematodo Meloidogyne en patrones de tomate a temperaturas del suelo superiores a los 28ºC

El gen Mi en tomate confiere resistencia al nematodo Meloidogyne, aunque su eficacia disminuye a temperaturas superiores a los 28ºC. Para determinar la resistencia relativa de 12 patrones y cultivares de tomate frente a M. arenaria y M. javanica se realizaron ensayos en un invernadero sin control climático donde las plantas estaban sujetas a fluctuaciones diarias de temperatura. En el transcurso de los ensayos, la temperatura del suelo fue superior a 28ºC durante 31 días en el primer ensayo (Exp.1) y durante 20 días en el segundo (Exp. 2). El intervalo de tiempo en que la temperatura se mantuvo por encima de los 28oC osciló entre 0,5 a 6 horas/día en el Exp.1 y entre 0,5 a 7,5 horas/día en Exp. 2. Los patrones Morgan, King Kong y Unifort consistentemente mostraron alta resistencia frente a M. arenaria y M. javanica en ambos experimentos, incluso con picos de temperaturas superiores a 28ºC durante parte del experimento. Los patrones Multifort y Maxifort expresaron menor grado de resistencia que los anteriores bajo las mismas condiciones experimentales. En general, la tasa de multiplicación de M. javanica fue mayor (P<0,05) que la de M. arenaria tanto en los tomates resistentes como en los susceptibles.Postprint (published version