Gravity model in the Korean highway

We investigate the traffic flows of the Korean highway system, which contains both public and private transportation information. We find that the traffic flow T(ij) between city i and j forms a gravity model, the metaphor of physical gravity as described in Newton's law of gravity, P(i)P(j)/r(ij)^2, where P(i) represents the population of city i and r(ij) the distance between cities i and j. It is also shown that the highway network has a heavy tail even though the road network is a rather uniform and homogeneous one. Compared to the highway network, air and public ground transportation establish inhomogeneous systems and have power-law behaviors.Comment: 13 page

Pobreza e espaço: padrões de segregação em São Paulo

ESTE ESTUDO busca atualizar o debate sobre a segregação urbana no Brasil, com base nos dados do Censo Demográfico de 2000 e da utilização de Sistemas de Informação Geográfica. Sustentamos que o modelo centro-periferia é uma simplificação genérica da forma urbana, sendo a periferia de São Paulo heterogênea, o que acarreta importantes conseqüências para as políticas públicas.<br>THIS STUDY intends to revisit the urban segregation debate in Brazil, taking into account new data from the 2000 Demographic Census and the use of geographic information systems. We argue that the center-periphery model is a rough simplification of the urban form, and that the São Paulo outskirts are heterogeneous, with important consequences for public policies