A coupled-map lattice showing complex behaviour in presence of a fully negative Lyapunov spectrum is considered. A phase transition from ordered to disordered evolution, upon changing diffusive coupling is studied in detail. Various indicators provide a coherent description of the scenario: the existence of an intermediate transition region characterized by an irregular alternancy of periodic a...

Localized nonlinear modes, or solitons, are obtained for the two-dimensional nonlinear Schrödinger equation with various external potentials that possess large variations from periodicity, i.e., vacancy defects, edge dislocations, and quasicrystal structure. The solitons are obtained by employing a spectral fixed-point computational scheme. Investigation of soliton evolution by direct numerical...

Translation from physics: ‘Glass’: a material which is hard and inflexible (like a solid) but is not completely ordered or lattice-like in its microscropic structure (thus, unlike a crystal or simple metals). ‘Spin’: pertaining to the magnetic spins of ions in a material. ‘Spin glass’: a material, effectively solid, which contains some irregular distribution of magnetizable ions. Basic laborato...

Binomial trees are very popular in both theory and applications of option pricing. As they often suffer from an irregular convergence behavior, improving this is an important task. We build upon a new version of the Edgeworth expansion for lattice models to construct new and quickly converging binomial schemes with a particular application to barrier options.

Individual-based models describing the migration and proliferation of a population of cells frequently restrict the cells to a predefined lattice. An implicit assumption of this type of lattice-based model is that a proliferative population will always eventually fill the lattice. Here, we develop a new lattice-free individual-based model that incorporates cell-to-cell crowding effects. We also...

This study attempts to exploit the potential of link directionality to increase the achievable capacities of ad hoc networks. When an IEEE 802.11 ad hoc network achieves capacity C by using a single channel, the targeted capacity by using two channels should be 2C. However, most of the dual-channel 802.11 protocols proposed in the literature appear only to be able to achieve less than 60% of th...

Although they lie at the conceptual core of a wide range of scientific questions, the notions of irregular or "random" arrangement and the process of randomization itself have never been unambiguously defined. Algorithmic implementation of these concepts requires a combinatorial, rather than a probability-theoretic, formulation. We introduce vector versions of approximate entropy to quantify th...

We present a method for creating geometric models of dendritic forms. Dendritic shapes are commonplace in the natural world; some examples of objects exhibiting dendritic shape include lichens, coral, trees, lightning, rivers, crystals, and venation patterns. Our method first generates a regular lattice with randomly weighted edges, then finds least-cost paths through the lattice. Multiple path...

We discuss stationary solutions of the nonlinear Schrödinger equation (NSE) applicable to several quantum spin, electron and classical lattice systems. We show that there may arise chaotic spatial structures in the form of incommensurate or irregular quantum states and trajectories in space. As a first (typical) example we consider a single electron which is strongly coupled with phonons on a 1...

Networks of workstations (NOWs) are becoming increasingly popular as a cost-effective alternative to parallel computers. Typically, these networks connect processors using irregular topologies, providing the wiring flexibility, scalability, and incremental expansion capability required in this environment. In some of these networks [1], packets are delivered using source routing. Due to the irr...