7,761 research outputs found
The Krause-Hegselmann Consensus Model with Discrete Opinions
The consensus model of Krause and Hegselmann can be naturally extended to the
case in which opinions are integer instead of real numbers. Our algorithm is
much faster than the original version and thus more suitable for applications.
For the case of a society in which everybody can talk to everybody else, we
find that the chance to reach consensus is much higher as compared to other
models; if the number of possible opinions Q<=7, in fact, consensus is always
reached, which might explain the stability of political coalitions with more
than three or four parties. For Q>7 the number S of surviving opinions is
approximately the same independently of the size N of the population, as long
as Q<N. We considered as well the more realistic case of a society structured
like a Barabasi-Albert network; here the consensus threshold depends on the
outdegree of the nodes and we find a simple scaling law for S, as observed for
the discretized Deffuant model.Comment: 12 pages, 6 figure
Universality of the Threshold for Complete Consensus for the Opinion Dynamics of Deffuant et al
In the compromise model of Deffuant et al., opinions are real numbers between
0 and 1 and two agents are compatible if the difference of their opinions is
smaller than the confidence bound parameter \epsilon. The opinions of a
randomly chosen pair of compatible agents get closer to each other. We provide
strong numerical evidence that the threshold value of \epsilon above which all
agents share the same opinion in the final configuration is 1/2, independently
of the underlying social topology.Comment: 8 pages, 4 figures, to appear in Int. J. Mod. Phys. C 15, issue
Scattering lengths and universality in superdiffusive L\'evy materials
We study the effects of scattering lengths on L\'evy walks in quenched
one-dimensional random and fractal quasi-lattices, with scatterers spaced
according to a long-tailed distribution. By analyzing the scaling properties of
the random-walk probability distribution, we show that the effect of the
varying scattering length can be reabsorbed in the multiplicative coefficient
of the scaling length. This leads to a superscaling behavior, where the
dynamical exponents and also the scaling functions do not depend on the value
of the scattering length. Within the scaling framework, we obtain an exact
expression for the multiplicative coefficient as a function of the scattering
length both in the annealed and in the quenched random and fractal cases. Our
analytic results are compared with numerical simulations, with excellent
agreement, and are supposed to hold also in higher dimensionsComment: 6 pages, 8 figure
Use of intraoral three-dimensional images for the identification of dental morphological traits related to ancestry estimation
Victim identification through dental features is one of the main objectives of forensic dentistry. In circumstances where information regarding antemortem dental records is missing, reconstruction of a biological profile can be useful as a first step toward personal identification. This reconstructive method provides valuable information, namely regarding the individual's ancestry, through the detection and degree of expression of dental morphological traits, which may help to restrict the number of candidates for identification. Technological advances allowed the development of alternative methods for dental evaluation, that complement or substitute those already in use in clinical practice. Among these, intraoral three-dimensional (3D) images are increasingly used in dentistry, as they have a high level of accuracy and are easy to obtain and store. However, a fundamental question regarding forensic dentistry is whether they allow recognition and analysis of dental morphological traits in detail, namely those related to ancestry. In this study, we evaluated 20 teeth morphological features using intraoral 3D imaging from 77 individuals from Northern Portugal. Our results showed that it was possible to identify and classify a large part of the main morphological traits used in the estimation of ancestry. As these 3D images present sufficient morphological detail to be classified, we believe that future applications of this technique can be expected in forensic dentistry
How the mere desire for certainty can lead to a preference for men in authority (particularly among political liberals)
Women are harmed by stereotypes about their fit for positions of authority and changing these stereotypes is not a simple task. As stereotypes have strong epistemic properties, individuals with a high need for cognitive closure (NCC; i.e., the desire for epistemic certainty) can be more likely to accept these stereotypes and, consequently, to prefer men in positions of authority. Consistent with the reactive liberal hypothesis, this effect could be actually more visible among individuals with both a high NCC and left-wing political orientations. We supported these hypotheses in a series of three studies. In Study 1 (N = 217), we found that manipulated NCC predicted preference for men in authority through stereotypes of women as not being fit for authority in a measurement-of-mediation design. In Study 2 (N = 151), we supported this effect in a mediation-as-process design. In Study 3 (N = 391), we found the indirect NCC effect on preference for men in authority was more visible among political liberals. A major implication of this work is that ways of changing the effect of these stereotypes should take into account the NCC, but particularly among individuals with left-wing beliefs
Number of spanning clusters at the high-dimensional percolation thresholds
A scaling theory is used to derive the dependence of the average number
of spanning clusters at threshold on the lattice size L. This number should
become independent of L for dimensions d<6, and vary as log L at d=6. The
predictions for d>6 depend on the boundary conditions, and the results there
may vary between L^{d-6} and L^0. While simulations in six dimensions are
consistent with this prediction (after including corrections of order loglog
L), in five dimensions the average number of spanning clusters still increases
as log L even up to L = 201. However, the histogram P(k) of the spanning
cluster multiplicity does scale as a function of kX(L), with X(L)=1+const/L,
indicating that for sufficiently large L the average will approach a finite
value: a fit of the 5D multiplicity data with a constant plus a simple linear
correction to scaling reproduces the data very well. Numerical simulations for
d>6 and for d=4 are also presented.Comment: 8 pages, 11 figures. Final version to appear on Physical Review
Texture Evolution During Isothermal, Isostrain, and Isobaric Loading of Polycrystalline Shape Memory NiTi
In situ neutron diffraction was used to provide insights into martensite variant microstructures during isothermal, isobaric, and isostrain loading in shape memory NiTi. The results show that variant microstructures were equivalent for the corresponding strain, and more importantly, the reversibility and equivalency were immediately evident in variant microstructures that were first formed isobarically but then reoriented to near random self-accommodated microstructures following isothermal deformation. Variant microstructures formed isothermally were not significantly affected by a subsequent thermal cycle under constant strain. In all loading cases considered, the resulting variant microstructure correlated with strain and did not correlate with stress. Based on the ability to select a variant microstructure for a given strain despite thermomechanical loading history, the results demonstrated here can be obtained by following any sequence of thermomechanical loading paths over multiple cycles. Thus, for training shape memory alloys (repeating thermomechanical cycling to obtain the desired variant microstructure), optimal paths can be selected so as to minimize the number of training cycles required, thereby increasing the overall stability and fatigue life of these alloys in actuator or medical applications
- …