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- Combined disaggregation of agricultural land uses, livestock numbers and crops' production: an entropy approachPublication . Xavier, António; Freitas, Maria de Belém; De Sousa Fragoso, R. M.This paper presents several combined agricultural data disaggregation models in order to recover the farms' land uses, the livestock numbers and main crops' productions. The proposed approach estimates incomplete information at disaggregated level through entropy, using an information prior, and generating information for a combined calculation use of data in the estimation of other variables. The models were applied to the region of Algarve, to some rural pilot areas (Salir-Ameixial-Cachopo and Alcoutim) for livestock data, since this data in some Algarve's inland areas is needed for a European forest fire prevention project, and to the agrarian zones in a more complex framework. The results are promising. They were validated, in cross reference to real data, having proven to be valid and reliable. The total error was small and a considerable level of information heterogeneity was recovered. The total error was about 27,9% for the counties' land uses and 21% for the agrarian zones, and for the livestock it was also acceptable. The level of heterogeneity recovered was always higher than 50%, revealing some improvements regarding previous studies.
- A desagregação espacial de dados agrícolas: aplicação de uma abordagem baseada na máxima entropia ao concelho de Castelo de VidePublication . Xavier, António; Martins, Maria de Belém; Fragoso, Rui Manuel de SousaThe purpose of this dissertation is to complement the lack of data related to the forest and agricultural occupation and the livestocks in Castelo de Vide. To solve the research problem a model of data disaggregation was developed, taking the utmost of previous information available in earlier studies. The proposed model was based on the ideas of generalized maximum entropy (GME) and minimum generalized crossed entropy (MGCE), in order to obtain a series of disaggregated data related to the forest and agricultural occupation, considering two levels of disaggregation and following two steps: 1) the creation of a basis at the aggregated level (Markov transition matrixes, estimated by the maximum entropy); 2) data disaggregation, based on the previous established basis. The model also involves two application variants: simultaneous disaggregation of data as well as a direct one (to solve the problems that might appear in the previous one and maximize the recovered information). Moreover, a model based on these principles is proposed to the disaggregation of the livestock data. The model is applied to the disaggregation of data in the municipality of Castelo de Vide. The results obtained in the process of direct disaggregation of the forest and agricultural occupation and livestock have shown to be reliable. They have been validated in the year of 1999, submitted to experts? opinions, to other sources of information and compared to the results of other methodologies. The analysis of the results showed that the forest and agricultural occupation of Alto Alentejo and Castelo de Vide after 1999 tend to be more homogeneous, with a strong domain of permanent pastures, and there is a shortage of certain livestocks (sheep and goats). The several CAP changes have had effects in Alto Alentejo and Castelo de Vide, since they have contributed to a larger extensification of the practice of agriculture and to the decline of traditional productions.