In this paper we construct thirteen different types of composite indices by linear combination of indicator variables (with and without outliers/data corruption). Weights of different indicator variables are obtained by maximization of the sum of squared (and, alternatively, absolute)...

Our objective in this paper is to compare the performance of the Differential Evolution (DE) and the Repulsive Particle Swarm (RPS) methods of global optimization. To this end, some relatively difficult test functions have been chosen. These functions are: Perm, Power-Sum, Bukin, Zero-Sum,...

The Portuguese National Action Plan for Employment (NAP) is the main instrument for the labour market policy. It was adopted in 1998. The NAP transposes to the Portuguese reality the contents of such guidelines, with the adequate adjustments required by the national specificities, establishing...

This is a short essay on open questions in urban economic theory.

Some programs and research networks are dealing with topics associated to the automtive sector and they observe one of the most significative sectores of modern economies. Because of that is so interesting to forecast some possible changes in an horizon of 10 to 20 years. But this exercse must...

Logarithmic spirals are abundantly observed in nature. Gastropods (such as nautilus, cowie, grove snail, thatcher, etc.) in the mollusca phylum have spiral shells, mostly exhibiting logarithmic spirals vividly. Spider webs show a similar pattern. The low-pressure area over Iceland and the...

In this paper we compare the performance of the Differential Evolution (DE) and the Repulsive Particle Swarm (RPS) methods of global optimization. To this end, seventy test functions have been chosen. Among these test functions, some are new while others are well known in the literature; some are...

Science and technology (S&T) are considered to be a central source, or at least a basic medium, of societal and industrial innovation, while innovation is conceived to basically feed the regeneration of our welfare. The suppliers of S&T in Europe as well as the users of their „products“, are...

We criticize the theories used to explain the size distribution of cities. They take an empirical fact and work backward to obtain assumptions on primitives. The induced theoretical assumptions on consumer behavior, particularly about their inability to insure against the city-level productivity...

The tomahawk bifurcation is used by Fujita et al. (1999) in a model with two regions to explain the formation of a core-periphery urban pattern from an initial uniform distribution. Baldwin et al. (2003) show that the tomahawk bifurcation disappears when the two regions have an uneven population...