90 research outputs found
Connectivity strategies to enhance the capacity of weight-bearing networks
The connectivity properties of a weight-bearing network are exploited to
enhance it's capacity. We study a 2-d network of sites where the weight-bearing
capacity of a given site depends on the capacities of the sites connected to it
in the layers above. The network consists of clusters viz. a set of sites
connected with each other with the largest such collection of sites being
denoted as the maximal cluster. New connections are made between sites in
successive layers using two distinct strategies. The key element of our
strategies consists of adding as many disjoint clusters as possible to the
sites on the trunk of the maximal cluster. The new networks can bear much
higher weights than the original networks and have much lower failure rates.
The first strategy leads to a greater enhancement of stability whereas the
second leads to a greater enhancement of capacity compared to the original
networks. The original network used here is a typical example of the branching
hierarchical class. However the application of strategies similar to ours can
yield useful results in other types of networks as well.Comment: 17 pages, 3 EPS files, 5 PS files, Phys. Rev. E (to appear
Nonequilibrium phase transitions in models of adsorption and desorption
The nonequilibrium phase transition in a system of diffusing, coagulating
particles in the presence of a steady input and evaporation of particles is
studied. The system undergoes a transition from a phase in which the average
number of particles is finite to one in which it grows linearly in time. The
exponents characterizing the mass distribution near the critical point are
calculated in all dimensions.Comment: 10 pages, 2 figures (To appear in Phys. Rev. E
Scale-free network on a vertical plane
A scale-free network is grown in the Euclidean space with a global
directional bias. On a vertical plane, nodes are introduced at unit rate at
randomly selected points and a node is allowed to be connected only to the
subset of nodes which are below it using the attachment probability: . Our numerical results indicate that the directed
scale-free network for belongs to a different universality class
compared to the isotropic scale-free network. For the
degree distribution is stretched exponential in general which takes a pure
exponential form in the limit of . The link length
distribution is calculated analytically for all values of .Comment: 4 pages, 4 figure
Kang-Redner Anomaly in Cluster-Cluster Aggregation
The large time, small mass, asymptotic behavior of the average mass
distribution \pb is studied in a -dimensional system of diffusing
aggregating particles for . By means of both a renormalization
group computation as well as a direct re-summation of leading terms in the
small reaction-rate expansion of the average mass distribution, it is shown
that \pb \sim \frac{1}{t^d} (\frac{m^{1/d}}{\sqrt{t}})^{e_{KR}} for , where and . In two
dimensions, it is shown that \pb \sim \frac{\ln(m) \ln(t)}{t^2} for . Numerical simulations in two dimensions supporting the analytical
results are also presented.Comment: 11 pages, 6 figures, Revtex
Transporte de fósforo e de potássio em colunas com agregados de um latossolo vermelho distrófico
A FAST RECURSIVE GIS ALGORITHM FOR COMPUTING STRAHLER STREAM ORDER IN BRAIDED AND NONBRAIDED NETWORKS
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