Socioeconophysics: Opinion Dynamics for number of transactions and price, a trader based model

Involving effects of media, opinion leader and other agents on the opinion of individuals of market society, a trader based model is developed and utilized to simulate price via supply and demand. Pronounced effects are considered with several weights and some personal differences between traders are taken into account. Resulting time series and probabilty distribution function involving a power law for price come out similar to the real ones.Comment: will be published in IJMPC 17 (2006

Alignment of velocity fields for video surveillance

Velocity fields play an important role in surveillance since they describe typical motion behaviors of video objects (e.g., pedestrians) in the scene. This paper presents an algorithm for the alignment of velocity fields acquired by different cameras, at different time intervals, from different viewpoints. Velocity fields are aligned using a warping function which maps corresponding points and vectors in both fields. The warping parameters are estimated by minimizing a non-linear least squares energy. Experimental tests show that the proposed model is able to compensate significant misalignments, including translation, rotation and scaling

Deblocking of interacting particle assemblies: from pinning to jamming

A wide variety of interacting particle assemblies driven by an external force are characterized by a transition between a blocked and a moving phase. The origin of this deblocking transition can be traced back to the presence of either external quenched disorder, or of internal constraints. The first case belongs to the realm of the depinning transition, which, for example, is relevant for flux-lines in type II superconductors and other elastic systems moving in a random medium. The second case is usually included within the so-called jamming scenario observed, for instance, in many glassy materials as well as in plastically deforming crystals. Here we review some aspects of the rich phenomenology observed in interacting particle models. In particular, we discuss front depinning, observed when particles are injected inside a random medium from the boundary, elastic and plastic depinning in particle assemblies driven by external forces, and the rheology of systems close to the jamming transition. We emphasize similarities and differences in these phenomena.Comment: 20 pages, 8 figures, submitted for a special issue of the Brazilian Journal of Physics entitled: Statistical Mechanics of Irreversible Stochastic Models - I

Opinion dynamics driven by leaders, media, viruses and worms

A model on the effects of leader, media, viruses, and worms and other agents on the opinion of individuals is developed and utilized to simulate the formation of consensus in society and price in market via excess between supply and demand. Effects of some time varying drives, (harmonic and hyperbolic) are also investigated. Key words: Opinion; Leader; Media; Market; Buyers; Sellers; ExcessComment: 14 pages, 7 figures (14, total) Will be published in IJMP

Addicted to Dollars

Dollarization, in a broad sense, is increasingly a defining characteristic of many emerging market economies. How important is this trend quantitatively and how important is it for the conduct of monetary policy and the choice of exchange rate regimes? Though these questions have become a hot topic in both the theory and policy literature, most efforts are remarkably uninformed by evidence, in no small part because meaningful data has been lacking, except for a very narrow range of assets. This paper attempts to move the discussion forward and shed light on the critical questions by proposing a measure of dollarization that is broad both conceptually and in terms of country coverage. We use this measure to identify trends in the evolution of dollarization in the developing world in the last two decades, and to ascertain the consequences that dollarization has had on the effectiveness of monetary and exchange rate policy. We find that, contrary to the general presumption in the literature, a high degree of dollarization does not seem to be an obstacle to monetary control or to disinflation. A level of dollarization does, however, appear to increase exchange rate pass-through, reinforcing the claim that fear of floating' is a greater problem for highly dollarized economies. We also review the developing countries' record in combating their addiction to dollars. Concretely, we try to explain why some countries have been able to avoid certain forms of the addiction, and examine the evidence on successful de-dollarization.

Debt Intolerance

This paper introduces the concept of "debt intolerance," which manifests itself in the extreme duress many emerging market economies experience at levels of indebtedness that would seem manageable by advanced country standards. The paper argues that "safe" external debt-to-GNP thresholds for debt-intolerant countries depend on the country's default and inflation history and may be as low as 15 percent in some cases. Debt intolerance is linked to the phenomenon of serial default that has plagued many countries over the past two centuries. Understanding and measuring debt intolerance is fundamental to assessing the problems of debt sustainability, debt restructuring, capital market integration, and the scope for international lending to ameliorate crises. The paper makes a first pass at quantifying debt intolerance, including delineating debtors' "clubs" and regions of vulnerability, based on a history of credit events for a large number of countries going back to the 1820s.macroeconomics, Debt Intolerance

Neighborhood models of minority opinion spreading

We study the effect of finite size population in Galam's model [Eur. Phys. J. B 25 (2002) 403] of minority opinion spreading and introduce neighborhood models that account for local spatial effects. For systems of different sizes N, the time to reach consensus is shown to scale as ln N in the original version, while the evolution is much slower in the new neighborhood models. The threshold value of the initial concentration of minority supporters for the defeat of the initial majority, which is independent of N in Galam's model, goes to zero with growing system size in the neighborhood models. This is a consequence of the existence of a critical size for the growth of a local domain of minority supporters

Divergent Time Scale in Axelrod Model Dynamics

We study the evolution of the Axelrod model for cultural diversity. We consider a simple version of the model in which each individual is characterized by two features, each of which can assume q possibilities. Within a mean-field description, we find a transition at a critical value q_c between an active state of diversity and a frozen state. For q just below q_c, the density of active links between interaction partners is non-monotonic in time and the asymptotic approach to the steady state is controlled by a time scale that diverges as (q-q_c)^{-1/2}.Comment: 4 pages, 5 figures, 2-column revtex4 forma

Probabilistic Bounds on the Length of a Longest Edge in Delaunay Graphs of Random Points in d-Dimensions

Motivated by low energy consumption in geographic routing in wireless networks, there has been recent interest in determining bounds on the length of edges in the Delaunay graph of randomly distributed points. Asymptotic results are known for random networks in planar domains. In this paper, we obtain upper and lower bounds that hold with parametric probability in any dimension, for points distributed uniformly at random in domains with and without boundary. The results obtained are asymptotically tight for all relevant values of such probability and constant number of dimensions, and show that the overhead produced by boundary nodes in the plane holds also for higher dimensions. To our knowledge, this is the first comprehensive study on the lengths of long edges in Delaunay graphsComment: 10 pages. 2 figures. In Proceedings of the 23rd Canadian Conference on Computational Geometry (CCCG 2011). Replacement of version 1106.4927, reference [5] adde

Grouper culture in floating net cages

The manual describes the culture of groupers (Epinephelus) in floating cages, providing a farming option for grouper growers and also a production alternative to the farmed species being done today, such as shrimp, milkfish and tilapia. The following aspects are covered: species identification for commercially cultured groupers; source of stock; net cage specifications; anchor; hides and shelters; nursery net cage operation; production cages; harvesting; post-harvest; profitability analysis of grouper cage culture; and, cost and return of growing grouper in cages