Multi-criteria decision analysis to assess the environmental and economic performance of using recycled gypsum cement and recycled aggregate to produce concrete: the case of Catalonia (Spain)

The production of virgin raw materials used in construction and the generation of construction and demolition waste (CDW) are key environmental issues in the construction industry. Portland cement and concrete are used extensively in the construction sector. Processing of CDW to produce recycled gypsum cement and recycled aggregates (RA) and their use in the production of structural and non-structural concrete are one way of slowing natural resource depletion and reducing the amount of CDW landfilled. This study proposes the application of multi-criteria decision analysis (MCDA) to compare the production of “green” concretes made from recycled gypsum cement (RGC) and RA with the production of conventional concrete made from natural aggregate and ordinary Portland cement. The VIKOR MCDA method was employed to determine the best or a set of good alternative(s) for concrete production, considering environmental and economic criteria. The life cycle assessment method was used to select the environmental evaluation criteria, and the reference cost of producing concrete alternatives in Spain was used to determine economic criteria. The results of this study, in which environmental and economic criteria were considered of equal weight, or one of the two criteria was given greater weight, showed that the best option for structural and non-structural concrete was the use of RGC and RA. In both cases, the worst alternative was conventional concrete. In conclusion, we found that the use of RGC and RA in concrete production is positive because it replaces the original raw material, reduces the environmental impact, and lowers the economic costs.Postprint (published version

The efficiency of refuse collection services in Spanish municipalities: do non-controllable variables matter?

The aim of this article is to analyse the technical efficiency and cost-efficiency of the refuse collection services in 73 municipalities located in Catalonia, Spain. The analysis has been carried out using a modification of the DEA model in three stages developed by Fried and Lovell (1996), that allows to take into account the influence of those factors that the producer cannot control (non-controllable variables). The results seem to back the hypothesis that non-controllable variables do not affect very much the ease of provision of the service, with the exception of few municipalities

Medición de la eficiencia en la provisión del servicio municipal de recogida de basuras

El trabajo empírico realizado sobre la medición de la eficiencia microeconómica en la provisión de bienes y servicios públicos es relativamente amplio, especialmente en lo que respecta al sector sanitario. Sin embargo, y curiosamente, las aplicaciones al campo de los servicios públicos locales son más bien escasa. En este marco de análisis se encuadra la comunicación que presentamos. Nuestra intención es profundizar en la medición de la eficiencia en el campo de los servicios públicos provistos por los municipios españoles. Concretamente, el programa de investigación que presentamos tiene un doble objetivo. En primer lugar, pretende medir la eficiencia en la provisión del servicio municipal de recogida de basuras utilizando técnicas no paramétricas. En segundo lugar, se tratarán de explicar los indicadores de eficiencia obtenidos mediante la estimación de un modelo econométrico en el que se incorporarán variables de tipo sociodemográfico y económico, de tipo político, de carácter fiscal y de tipo organizativo de los municipios estudiado

Análisis territorial mediante modelación de viajes: caso de estudio Orbital B-40 de Barcelona

Esta ponencia hace parte de la Tesis Doctoral “Efectos de la implementación de la orbital B-40 y de sus obras anexas en el equilibrio territorial de Catalunya” en desarrollo actualmente. El objetivo específico de esta comunicación es presentar la metodología desarrollada para determinar una estructura de modelación acotada a origen, que prediga proporciones de llegada, y sea sensible al cambio en los atractivos de los destinos y al cambio en la función de fricción, además que se pueda calibrar con una matriz observada.Peer Reviewe

Bootstrap-based procedures for inference in nonparametric receiver-operating characteristic curve regression analysis

Prior to using a diagnostic test in a routine clinical setting, the rigorous evaluation of its diagnostic accuracy is essential. The receiver-operating characteristic curve is the measure of accuracy most widely used for continuous diagnostic tests. However, the possible impact of extra information about the patient (or even the environment) on diagnostic accuracy also needs to be assessed. In this paper, we focus on an estimator for the covariate-specific receiver-operating characteristic curve based on direct regression modelling and nonparametric smoothing techniques. This approach defines the class of generalised additive models for the receiver-operating characteristic curve. The main aim of the paper is to offer new inferential procedures for testing the effect of covariates on the conditional receiver-operating characteristic curve within the above-mentioned class. Specifically, two different bootstrap-based tests are suggested to check (a) the possible effect of continuous covariates on the receiver-operating characteristic curve and (b) the presence of factor-by-curve interaction terms. The validity of the proposed bootstrap-based procedures is supported by simulations. To facilitate the application of these new procedures in practice, an R-package, known as npROCRegression, is provided and briefly described. Finally, data derived from a computer-aided diagnostic system for the automatic detection of tumour masses in breast cancer is analyse

La configuración de los derechos políticos de los militares en el marco jurídico - constitucional establecido para las Fuerzas Armadas

Programa Oficial de Doctorado en DerechoPresidente: Luis Felipe López Álvarez; Secretario: Félix Vacas Fernández; Vocal: José Luis Rodríguez-Villasante y Priet

Bootstrap-based procedures for inference in nonparametric ROC regression analysis

Before the use of a diagnostic test in a routine clinical setting, the rigorous evaluation of its diagnostic accuracy is an essential step. The receiver operating characteristic (ROC) curve is the measure of accuracy most widely used for continuous diagnostic tests. However, the possible impact of extra information about the patient (or even the environment) on diagnostic accuracy needs to be also assessed. In this paper, attention is focused on an estimator for the covariate-specific ROC curve based on direct regression modelling and nonparametric smoothing techniques. This approach defines the class of generalized additive models for the ROC curve (ROC-GAM). The main aim of the paper is to offer new inferential procedures for testing the effect of co- variates over the conditional ROC curve within the ROC-GAM context. Specifically, two different bootstrap-based tests are suggested to check (a) the possible effect of continuous covariates on the ROC curve; and (b) the presence of factor-by-curve interaction terms. The validity of the proposed bootstrap-based procedures is supported by simulations. To facilitate the application of these new procedures in practice, an R-package, known as npROCRegression, is provided and briefly described. Finally, data derived from a computed-aided diagnostic (CAD) system for the automatic detection of tumour masses in breast cancer is analysed

Flexible quantile regression models: application to the study of the purple sea urchin

In many applications, it is often of interest to assess the possible relationships between covariates and quantiles of a response variable through a regression model. In some instances, the effects of continuous covariates on the outcome are highly nonlinear. Consequently, appropriate modelling has to take such flexible smooth effects into account. In this work, various flexible quantile regression techniques were reviewed and compared by simulation. Finally, all the techniques were used to construct the overall zone specific reference curves of morphologic measures of sea urchin Paracentrotus lividus (Lamarck, 1816) located in NW SpainPeer Reviewe

Flexible quantile regression models : application to the study of the purple sea urchin

In many applications, it is often of interest to assess the possible relationships between covariates and quantiles of a response variable through a regression model. In some instances, the effects of continuous covariates on the outcome are highly nonlinear. Consequently, appropriate modelling has to take such flexible smooth effects into account. In this work, various flexible quantile regression techniques were reviewed and compared by simulation. Finally, all the techniques were used to construct the overall zone specific reference curves of morphologic measures of sea urchin Paracentrotus lividus (Lamarck, 1816) located in NW Spain