[en] Extension of photoelasticity into infrared region up to wave length of 14μ is possible, using existing technology. Selection of components, taking into consideration their spectral characteristics, is discussed. Full field system using TV display and pointwise method were evaluated. Economical consideration limits the practical use to 2.6μ. Several materials were calibrated in the near-infrared region and results reported in this paper. (orig.)

[en] The organizational development of growing random networks is investigated. These growing networks are built by adding nodes successively, and linking each to an earlier node of degree k with an attachment probability A_k. When A_k grows more slowly than linearly with k, the number of nodes with k links, N_k(t), decays faster than a power law in k, while for A_k growing faster than linearly in k, a single node emerges which connects to nearly all other nodes. When A_k is asymptotically linear, N_k(t)∼tk^-ν, with ν dependent on details of the attachment probability, but in the range 2<ν<∞. The combined age and degree distribution of nodes shows that old nodes typically have a large degree. There is also a significant correlation in the degrees of neighboring nodes, so that nodes of similar degree are more likely to be connected. The size distributions of the in and out components of the network with respect to a given node-namely, its 'descendants' and 'ancestors'-are also determined. The in component exhibits a robust s^-2 power-law tail, where s is the component size. The out component has a typical size of order lnt, and it provides basic insights into the genealogy of the network

[en] The in-degree and out-degree distributions of a growing network model are determined. The in-degree is the number of incoming links to a given node (and vice versa for out-degree). The network is built by (i) creation of new nodes which each immediately attach to a preexisting node, and (ii) creation of new links between preexisting nodes. This process naturally generates correlated in-degree and out-degree distributions. When the node and link creation rates are linear functions of node degree, these distributions exhibit distinct power-law forms. By tuning the parameters in these rates to reasonable values, exponents which agree with those of the web graph are obtained

[en] The kinetics of diffusion-controlled two-species annihilation, A+B → O and single-species ballistically-controlled annihilation, A+A → O are investigated. For two-species annihilation, we describe the basic mechanism that leads to the formation of a coarsening mosaic of A- and B-domains. The implications of this picture on the distribution of reactants is discussed. For ballistic annihilation, dimensional analysis shows that the concentration and rms velocity decay as c∼t^-α and v∼t^-β, respectively, with α+β = 1 in any spatial dimension. Analysis of the Boltzmann equation for the evolution of the velocity distribution yields accurate predictions for the kinetics. New phenomena associated with discrete initial velocity distributions and with mixed ballistic and diffusive reactant motion are also discussed. (author)

[en] We introduce a socially motivated extension of the voter model in which individual voters are also influenced by two opposing, fixed-opinion news sources. These sources forestall consensus and instead drive the population to a politically polarized state, with roughly half the population in each opinion state. Two types of social networks for the voters are studied: (a) the complete graph of N voters and, more realistically, (b) the two-clique graph with N voters in each clique. For the complete graph, many dynamical properties are soluble within an annealed-link approximation, in which a link between a news source and a voter is replaced by an average link density. In this approximation, we show that the average consensus time grows as , with . Here p is the probability that a voter consults a news source rather than a neighboring voter, and is the link density between a news source and voters, so that can be greater than 1. The polarization time, namely, the time to reach a politically polarized state from an initial strong majority state, is typically much less than the consensus time. For voters on the two-clique graph, either reducing the density of interclique links or enhancing the influence of news sources again promotes polarization. (paper: interdisciplinary statistical mechanics)

[en] As a strategy to complete games quickly, we investigate one-dimensional random walks where the step length increases deterministically upon each return to the origin. When the step length after the kth return equals k, the displacement of the walk x grows linearly in time. Asymptotically, the probability distribution of displacements is a purely exponentially decaying function of |x|/t. The probability E(t, L) for the walk to escape a bounded domain of size L at time t decays algebraically in the long-time limit, E(t, L) ∼ L/t². Consequently, the mean escape time (t) ∼ Lln L, while (tⁿ) ∼ L^2n-1 for n > 1. Corresponding results are derived when the step length after the kth return scales as k^α for α > 0

[en] We show that a two-dimensional convection-diffusion problem with a radial sink or source at the origin may be recast as a pure diffusion problem in a fictitious space in which the spatial dimension is continuously tunable with the Peclet number. This formulation allows us to probe various diffusion-controlled processes in non-integer dimensions

[en] We study the role of finiteness and fluctuations about average quantities for basic structural properties of growing networks. We first determine the exact degree distribution of finite networks by generating function approaches. The resulting distributions exhibit an unusual finite-size scaling behaviour and they are also sensitive to the initial conditions. We argue that fluctuations in the number of nodes of degree k become Gaussian for fixed degree as the size of the network diverges. We also characterize the fluctuations between different realizations of the network in terms of higher moments of the degree distribution

[en] We study consensus formation in interacting systems that evolve by multi-state majority rule and by plurality rule. In an update event, a group of G agents (with G odd), each endowed with an s-state spin variable, is specified. For majority rule, all group members adopt the local majority state; for plurality rule the group adopts the local plurality state. This update is repeated until a final consensus state is generally reached. In the mean field limit, the consensus time for an N-spin system increases as ln N for both majority and plurality rules, with an amplitude that depends on s and G. For finite spatial dimensions, domains undergo diffusive coarsening in majority rule when s or G is small. For larger s and G, opinions spread ballistically from the few groups with an initial local majority. For plurality rule, there is always diffusive domain coarsening towards consensus

[en] We investigate a class of network growth rules that are based on a redirection algorithm wherein new nodes are added to a network by linking to a randomly chosen target node with some probability 1 − r or linking to the parent node of the target node with probability r. For fixed 0 < r < 1, the redirection algorithm is equivalent to linear preferential attachment. We show that when r is a decaying function of the degree of the parent of the initial target, the redirection algorithm produces sublinear preferential attachment network growth. We also argue that no local redirection algorithm can produce superlinear preferential attachment. (paper)