178,017 research outputs found
International Terrorism, International Trade, and Borders
This paper shows that terrorism reduces bilateral trade flows, in real terms, by raising trading costs and hardening borders. Countries sharing a common land border and suffering from terrorism trade much less than neighboring or distant countries that are free of terrorism. The impact of terrorism on bilateral trade declines as distance between trading partners increases. This result suggests that terrorism redirects some trade from close to more distant countries. Our findings are robust in the presence of a variety of other calamities such as natural disasters or financial crises.financial crisis, natural disaster, trade gravity model, transaction cost
A generalized spin model of financial markets
We reformulate the Cont-Bouchaud model of financial markets in terms of
classical "super-spins" where the spin value is a measure of the number of
individual traders represented by a portfolio manager of an investment agency.
We then extend this simplified model by switching on interactions among the
super-spins to model the tendency of agencies getting influenced by the opinion
of other managers. We also introduce a fictitious temperature (to model other
random influences), and time-dependent local fields to model slowly changing
optimistic or pessimistic bias of traders. We point out close similarities
between the price variations in our model with super-spins and total
displacements in an -step Levy flight. We demonstrate the phenomena of
natural and artificially created bubbles and subsequent crashes as well as the
occurrence of "fat tails" in the distributions of stock price variations.Comment: 11 pages LATEX, 7 postscript figures; longer text with theoretical
analysis, more accurate numerical data, better terminology, additional
references. Accepted for publication in European Physical Journal
Evolution of Vocabulary on Scale-free and Random Networks
We examine the evolution of the vocabulary of a group of individuals
(linguistic agents) on a scale-free network, using Monte Carlo simulations and
assumptions from evolutionary game theory. It is known that when the agents are
arranged in a two-dimensional lattice structure and interact by diffusion and
encounter, then their final vocabulary size is the maximum possible. Knowing
all available words is essential in order to increase the probability to
``survive'' by effective reproduction. On scale-free networks we find a
different result. It is not necessary to learn the entire vocabulary available.
Survival chances are increased by using the vocabulary of the ``hubs'' (nodes
with high degree). The existence of the ``hubs'' in a scale-free network is the
source of an additional important fitness generating mechanism.Comment: 10 pages, 3 Figures, accepted in Physica
Spoken affect classification : algorithms and experimental implementation : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Computer Science at Massey University, Palmerston North, New Zealand
Machine-based emotional intelligence is a requirement for natural interaction between humans and computer interfaces and a basic level of accurate emotion perception is needed for computer systems to respond adequately to human emotion. Humans convey emotional information both intentionally and unintentionally via speech patterns. These vocal patterns are perceived and understood by listeners during conversation. This research aims to improve the automatic perception of vocal emotion in two ways. First, we compare two emotional speech data sources: natural, spontaneous emotional speech and acted or portrayed emotional speech. This comparison demonstrates the advantages and disadvantages of both acquisition methods and how these methods affect the end application of vocal emotion recognition. Second, we look at two classification methods which have gone unexplored in this field: stacked generalisation and unweighted vote. We show how these techniques can yield an improvement over traditional classification methods
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