18,528 research outputs found
Mean-Field and Non-Mean-Field Behaviors in Scale-free Networks with Random Boolean Dynamics
We study two types of simplified Boolean dynamics over scale-free networks,
both with synchronous update. Assigning only Boolean functions AND and XOR to
the nodes with probability and , respectively, we are able to analyze
the density of 1's and the Hamming distance on the network by numerical
simulations and by a mean-field approximation (annealed approximation). We show
that the behavior is quite different if the node always enters in the dynamic
as its own input (self-regulation) or not. The same conclusion holds for the
Kauffman KN model. Moreover, the simulation results and the mean-field ones (i)
agree well when there is no self-regulation, and (ii) disagree for small
when self-regulation is present in the model.Comment: 12 pages, 7 figure
A Political Economy Model of Regulation Explained Through Fuzzy Logics
The basic problem of environmental regulation involves the government trying to induce a polluter to take socially desirable actions, which ostensibly are not in the best interest of the polluter. But the government may not always be able to precisely control the polluter. To further complicate matters the government faces a complex problem of determining exactly what level of pollution is best for society. In reality the government faces pressures from consumers and polluters. There are some important lessons to gather from the analysis of current models of regulation. One is that there are many imperfect links between the legislature and the pollution-generating process. In this case regulation may be excessively costly, may result in considerable cheating, and may result in excessive pollution. Another lesson is that legislature does not necessarily act as an efficient benevolent maximizer of social well-being. The authors intend in this paper to explain the current view of political models of regulation, analysing them for their complexity, and attempt to provide a reasonable explanation of their functioning recurring to fuzzy logics. Understanding how the browns and greens interact with the legislature and regulatory agencies can to some extent explain the current environmental regulations. The fuzzy approach, intends to allow for easier understanding of these interactions, and provide an answer for more effective decision making. Keywords: Environmental Regulation, Environmental Economics, Fuzzy Logics, Models, Pollution Control, Sustainability
Imaginação, linguagem e consumo
Com base em um conto do livro Marcovaldo ou as estações da cidade (1973), do escritor Italo Calvino, podemos inferir uma série de entendimentos da literatura acerca do consumo compreendido neste texto pela visão heideggeriana, que sustenta ser o consumo uma necessidade ontológica. ______________________________________________________________________________________ ABSTRACTBased on a short story in the book Marcovaldo ou as estações da cidade (1973), by Italo Calvino, we can infer a series of understanding about consumption. We accept here Heiddegger’s point of view according to which consumption is an onthological necessity
Metallic Continuum Quantum Ferromagnets at Finite Temperature
We study via renormalization group (RG) and large N methods the problem of
continuum SU(N) quantum Heisenberg ferromagnets (QHF) coupled to gapless
electrons. We establish the phase diagram of the dissipative problem and
investigate the changes in the Curie temperature, magnetization, and magnetic
correlation length due to dissipation and both thermal and quantum
fluctuations. We show that the interplay between the topological term (Berry's
phase) and dissipation leads to non-trivial effects for the finite temperature
critical behavior.Comment: Corrected typos, new discussion of T=0 results, to appear in
Europhys. Let
Projeto amplo de divulgação de resultados de projeto conjunto entre a Faculdade de Medicina de Ribeirão Preto e o Instituto de Física de São Carlos da Universidade de São Paulo
- …