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| Author(s): |
Alexandra Akamine
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Carlos. |
| Institution: | Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD) |
| Defense date: | 2005-09-27 |
| Examining board members: |
Antonio Nelson Rodrigues da Silva;
Rui António Rodrigues Ramos;
José Alex Sant'Anna
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| Advisor: | Antonio Nelson Rodrigues da Silva |
| Abstract | |
The rapid growth of Brazilian cities, without a previous planning of their expansion (including land use and occupation), causes many inconveniences for the population related to their transportation, as they must cover longer distances. This asks for an understanding of the city areas limits, the services currently offered to the community in each area, and the users of these services, not only in quantitative terms, but also in terms of spatial distribution. Moreover, the knowledge of the demand evolution in time and its spatial location allows the evaluation of many planning scenarios for managing the demand and the supply, and it is possible, for example, to foresee the regions where the demand is going to be concentrated. Other aspects that must be evaluated are the origin, destination and number of trips that occur in a determined set of tracts, which can be predicted by the spatial interaction models. Therefore, some studies were made with the objective of evaluating the performance of Spatial Interaction Models based on Artificial Neural Networks (ANNs). It was observed in these studies, some difficulty in selecting the neural network configuration that best models the problem. As in the majority of research that uses Artificial Neural Networks for the construction of that kind of model, the network parameters are randomly chosen and, even if one can obtain satisfactory results by varying these parameters, the neural net used may not be producing the optimal solution. The objective of this work is to evaluate the use of different alternatives, such as the Genetic Algorithms (GAs) optimization technique and the bootstrapping estimation method, as supporting tools to select Artificial Neural Networks configurations applied to Spatial Interaction Models, and to evaluate the spatial distribution of the residual (errors) prediction results. The research was developed in a Geographic Information System (GIS) and the data used for this application reflects the changes in the spatial distribution of the demand for education services in a Brazilian medium-sized city (São Carlos, SP) throughout two years. The results obtained showed that although neural models are suitable for estimating transportation flows, gravity models are able to produce very good and precise estimates of the future spatial distribution of the demand for educational facilities. This is very important for the planning process aiming at the reduction of displacement costs of students in the future, given the simplicity of the gravity model structure and its straightforward implementation (AU) | |