Numerical simulation of a class of models that combine several mechanisms of dissipation: fracture, plasticity, viscous dissipation

We study a class of time evolution models that contain dissipation mech- anisms exhibited by geophysical materials during deformation: plasticity, viscous dissipation and fracture. We formally prove that they satisfy a Clausius-Duhem type inequality. We describe a semi-discrete time evolu- tion associated with these models, and report numerical 1D and 2D traction experiments, that illustrate that several dissipation regimes can indeed take place during the deformation. Finally, we report 2D numerical simulation of an experiment by Peltzer and Tapponnier, who studied the indentation of a layer of plasticine as an analogue model for geological materials

Vector spaces for historical linguistics : using distributional semantics to study syntactic productivity in diachrony

This paper describes an application of dis- tributional semantics to the study of syn- tactic productivity in diachrony, i.e., the property of grammatical constructions to attract new lexical items over time. By providing an empirical measure of seman- tic similarity between words derived from lexical co-occurrences, distributional se- mantics not only reliably captures how the verbs in the distribution of a construc- tion are related, but also enables the use of visualization techniques and statistical modeling to analyze the semantic develop- ment of a construction over time and iden- tify the semantic determinants of syntactic productivity in naturally occurring data

Cooperative differential space-time spreading for the asynchronous relay aided CDMA uplink using interference rejection spreading code

Abstract—This letter proposes a differential Space–Time Coding (STC) scheme designed for asynchronous cooperative networks, where neither channel estimation nor symbol-level synchroniza-tion is required at the cooperating nodes. More specifically, our system employs differential encoding during the broadcast phase and a Space–Time Spreading (STS)-based amplify-and-forward scheme during the cooperative phase in conjunction with inter-ference rejection direct sequence spreading codes, namely Loosely Synchronized (LS) codes. Our simulation results demonstrate that the proposed Cooperative Differential STS (CDSTS) scheme is ca-pable of combating the effects of asynchronous uplink transmis-sions without any channel state information. Index Terms—Asynchronous cooperation, cooperative diversity, differential space–time spreading, loosely synchronized codes. I

Compact phase space, cosmological constant, discrete time

We study the quantization of geometry in the presence of a cosmological constant, using a discretiza- tion with constant-curvature simplices. Phase space turns out to be compact and the Hilbert space finite dimensional for each link. Not only the intrinsic, but also the extrinsic geometry turns out to be discrete, pointing to discreetness of time, in addition to space. We work in 2+1 dimensions, but these results may be relevant also for the physical 3+1 case.Comment: 6 page

Modelling exchange rates: smooth transitions, neural networks, and linear models

The goal of this paper is to test for and model nonlinearities in several monthly exchange rates time series. We apply two different nonlinear alternatives, namely: the artificial neural network time series model estimated with Bayesian regularization and a flexible smooth transition specifica-tion, called the neuro-coefficient smooth transition autoregression. The linearity test rejects the null hypothesis of linearity in ten out of fourteen series. We compare, using different measures, the fore-casting performance of the nonlinear specifications with the linear autoregression and the random walk models.

The environmental Kuznets curve : evidence from time series data for Germany

In recent years, extensive literature on the Environmental Kuznets Curve lead- ing to optimistic policy conclusions has attracted great attention. However, the underlying cross-section estimations are not very reliable. Accordingly, this contribution uses time series data for a single country with dependable data quality : Germany. The results of the traditional reduced-form specification do not support the EKC hypothesis. However, with a specification in the tradi- tion of error correction models, which are more appropriate in the presence of non-stationary time series, it is found that the typical EKC pattern can be confirmed.Environmental Kuznets Curve, Error Correction Model, Time Series Data