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C. Schulze

Publications and source records attributed to C. Schulze.

7 recordsLinked to original sources
arXiv2007

Boundary effects in a three-state modified voter model for languages

The standard three-state voter model is enlarged by including the outside pressure favouring one of the three choices and by adding some biased internal random noise. The Monte Carlo simulations are motivated by states with the population divided into three groups of various affinities to each other. We show the crucial influence of the boundaries for moderate lattice sizes like 500 x 500. By removing the fixed boundary at one side, we demonstrate that this can lead to the victory of one single choice. Noise in contrast stabilizes the choices of all three populations. In addition, we compute the persistence probability, i.e., the number of sites who have never changed their opinion during the simulation, and we consider the case of "rigid-minded" decision makers.

physics.soc-ph↗
arXiv2007

Birth, survival and death of languages by Monte Carlo simulation

Simulations of physicists for the competition between adult languages since 2003 are reviewed. How many languages are spoken by how many people? How many languages are contained in various language families? How do language similarities decay with geographical distance, and what effects do natural boundaries have? New simulations of bilinguality are given in an appendix.

physics.soc-ph↗
arXiv2006

Habitat width along a latitudinal gradient

We use the Chowdhury ecosystem model, one of the most complex agent-based ecological models, to test the latitude-niche breadth hypothesis, with regard to habitat width, i.e., whether tropical species generally have narrower habitats than high latitude ones. Application of the model has given realistic results in previous studies on latitudinal gradients in species diversity and Rapoport's rule. Here we show that tropical species with sufficient vagility and time to spread into adjacent habitats, tend to have wider habitats than high latitude ones, contradicting the latitude-niche breadth hypothesis.

q-bio.PE↗
arXiv2006

Bit-strings and other modifications of Viviane model for language competition

The language competition model of Viviane de Oliveira et al is modified by associating with each language a string of 32 bits. Whenever a language changes in this Viviane model, also one randomly selected bit is flipped. If then only languages with different bit-strings are counted as different, the resulting size distribution of languages agrees with the empirically observed slightly asymmetric log-normal distribution. Several other modifications were also tried but either had more free parameters or agreed less well with reality.

physics.soc-ph↗
arXiv2006

Non-equilibrium and Irreversible Simulation of Competition among Languages

The bit-string model of Schulze and Stauffer (2005) is applied to non-equilibrium situations and then gives better agreement with the empirical distribution of language sizes. Here the size is the number of people having this language as mother tongue. In contrast, when equilibrium is combined with irreversible mutations of languages, one language always dominates and is spoken by at least 80 percent of the population.

physics.soc-ph↗
arXiv2004

Discretized opinion dynamics of Deffuant on scale-free networks

The consensus model of Deffuant et al is simplified by allowing for many discrete instead of infinitely many continuous opinions, on a directed Barabasi-Albert network. A simple scaling law is observed. We then introduce noise and also use a more realistic network and compare the results. Finally, we look at a multi-layer model representing various age levels, and we include advertising effects.

cond-mat.stat-mech↗