12,735 research outputs found
Multidimensional Localized Solitons
Recently it has been discovered that some nonlinear evolution equations in
2+1 dimensions, which are integrable by the use of the Spectral Transform,
admit localized (in the space) soliton solutions. This article briefly reviews
some of the main results obtained in the last five years thanks to the renewed
interest in soliton theory due to this discovery. The theoretical tools needed
to understand the unexpected richness of behaviour of multidimensional
localized solitons during their mutual scattering are furnished. Analogies and
especially discrepancies with the unidimensional case are stressed
Economies of Scale for Real Estate Investment Trusts
Using the translog cost function to estimate economies of scale for a sample of Real Estate Investment Trusts for the years 1992-1994, we find significant evidence that economies of scale exist for REITs for all years examined. The results show that measurement of scale economies is sensitive to the model used for the measurement. Individual characteristics of the REIT, such as type of management and degree of leverage, affect the magnitude of the scale economy. Additional variables accounting for property type diversification and geographic influences have little additional impact on the measured scale economies. Finally, the measured economies of scale for REITs vary considerably over time.
Waves in the Skyrme--Faddeev model and integrable reductions
In the present article we show that the Skyrme--Faddeev model possesses
nonlinear wave solutions, which can be expressed in terms of elliptic
functions. The Whitham averaging method has been exploited in order to describe
slow deformation of periodic wave states, leading to a quasi-linear system. The
reduction to general hydrodynamic systems have been considered and it is
compared with other integrable reductions of the system.Comment: 16 pages, 5 figure
Impact of Correlated Mobility on Delay-Throughput Performance in Mobile Ad-Hoc Networks
AbstractâWe extend the analysis of the scaling laws of wireless ad hoc networks to the case of correlated nodes movements, which are commonly found in real mobility processes. We consider a simple version of the Reference Point Group Mobility model, in which nodes belonging to the same group are constrained to lie in a disc area, whose center moves uniformly across the network according to the i.i.d. model. We assume fast mobility conditions, and take as primary goal the maximization of pernode throughput. We discover that correlated node movements have huge impact on asymptotic throughput and delay, and can sometimes lead to better performance than the one achievable under independent nodes movements. I. INTRODUCTION AND RELATED WORK In the last few years the store-carry-forward communication paradigm, which allows nodes to physically carry buffered dat
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