Ricardo Coelho de Faria

Efficiency of Brazilian Public and Private Water Utilities

This paper compares cost efficiencies of Brazilian public and private companies of water supply. To measure efficiency a Cobb-Douglas stochastic cost frontier model including technical effects is estimated by maximum likelihood to a panel of Brazilian firms for the period 2002 -2004. The statistical results indicate that there is evidence that public firms are more efficient although the difference in efficiency is declining over time. Overall the system of water and sewerage supply is becoming more efficient over time.

Cenários e perspectivas para o setor de saneamento e sua interface com os recursos hídricos

This paper analyses the prospects for sanitation based upon its management model as well as in its interface with the area of hydric resources. Two alternative scenarios are considered in this analysis. In the first scenario there are neither institutional nor legal changes in the current model of sanitation management. The second scenario assumes the approval of the Law Project number 4.147/2001, which stablishes national guidelines for sanitation and sets the collaboration of ANA - Agencia Nacional de Aguas - in this area. The paper shows that there are limits for a new management model in both cases.

Políticas de precificação do setor de saneamento urbano no Brasil: as evidências do equilíbrio de baixo nível

The existence of a low level equilibrium balance in the supply of urban sewage services is analysed in this essay. The low level equilibrium hypothesis is related to the model by Spiller e Savedoff (1999) for Latin American countries. In their view, government opportunism and populism lead towards prices below costs of providing sewage service in developing countries. This is the starting point of a vicious circle, leading towards low quality of public utility services. Like other countries in Latin America, data for Brazil demonstrate that, with few exceptions, the low level equilibrium of water and sewage supply services in urban areas. However, some particularities in the Brazilian reality suggest that this low level equilibrium may be explained in economic terms. It is shown that wealthier states and municipalities provide high quality services, regardless of the regulatory system.

Applying combinatorial neural model for vegetable production management

This paper presents a study on the effects of the combination of different vegetables and some socio-economic variables in the economic results of the carrot cropping. Experts recognise that some combinations of cropping can produce synergistic effects that can lead to profits or losses, depending on the factors of production involved. However, the analysis of the results of cropping multiple varieties simultaneously involves a space of possibilities whose treatment is not trivial. Among the alternatives available for analysing such a problem, this study explored the Combinatorial Neural Model (CNM) which ensures the generation of hypotheses for all possible combinations, according to the parameters set to the model. The study is based on data collected from farms in Brasilia, Brazil. First, a preprocessing on the data is presented in order to provide information on the data nature and distribution, and some univariate and bi-dimensional analysis is shown. Next, the results generated by CNM are explored and the research limits and future work are discussed.

A reasoning-based strategy for exploring the synergy among alternative crops

This paper focuses on the problem of choosing one among many alternatives, each one expressed as a combination of factors. The problem is approached with a reasoning-based strategy that takes into account the relations among the alternatives discovered by means of a data mining technique. The problem of choosing a combination of different vegetables based on the synergistic effects of the combination and considering some socioeconomic variables is taken as a case study. The idea is to identify combinations that lead to gains in productivity, profitability, and lower costs. Experts recognize that some combinations of cultures can generate synergistic effects that can lead to profits or losses, depending on the production variables involved. However, the analysis of the results of the cultivation of multiple varieties involves a space of possibilities whose treatment is not trivial. Among the alternatives available, this study explored the Combinatorial Neural Model (CNM) that assures the hypotheses generation for all possible combinations, within limits defined by the model parameters. The study was carried out on data collected from farms in the Brazilian Federal District. Two approaches to the problem are presented: (i) the first one based on univariate and bi-dimensional data analysis and (ii) a multidimensional analysis based on the CNM results.