Search results for "Time-serie"

Quantifying Irrigated Winter Wheat LAI in Argentina Using Multiple Sentinel-1 Incidence Angles

2022

Synthetic aperture radar (SAR) data provides an appealing opportunity for all-weather day or night Earth surface monitoring. The European constellation Sentinel-1 (S1) consisting of S1-A and S1-B satellites offers a suitable revisit time and spatial resolution for the observation of croplands from space. The C-band radar backscatter is sensitive to vegetation structure changes and phenology as well as soil moisture and roughness. It also varies depending on the local incidence angle (LIA) of the SAR acquisition’s geometry. The LIA backscatter dependency could therefore be exploited to improve the retrieval of the crop biophysical variables. The availability of S1 radar time-series data at d…

Monitoring the invasion of an exotic tree (Ailanthus altissima) (Mill.) Swingle with Landsat satellite time series imagery in urban forest.

2015

In the Mediterranean area, one the most threat tree to various ecosystems is Ailanthus altissima (Mill.) Swingle. This is an aggressive invasive species common in natural and semi-natural habitat. Monitoring and mapping of invasive species is an important information for the conservation and management of ecosystems. The study of distribution and diffusion of invasive species are useful to assess their environmental impacts, formulate effective control strategies, and forecast potential spread. The main target of this work is to examine the feasibility of mapping the expansion of A. altissima using remote sensing techniques in a highly complex urban forest setting. Remote sensing has been a…

About time of occurrence of rainy days for Mediterranean and (sub)-Alpine areas

2012

Fading mitigation coding techniques for space to ground free space optical communications

2014

Fading mitigation coding techniques for space to ground free space optical communications (Euro Med Telco 2014)

2014

In this manuscript, a Geostationary satellite-toground Free Space Optics (FSO) downlink channel model has been implemented, which is able to predict temporal irradiance fluctuations caused by scintillation at a wide range of turbulence conditions and for different values of the zenith angle. In order to mitigate fading events that occur in FSO communications, we have also tested the performance of three different families of Rateless Codes (Luby Transform, Raptor and RaptorQ) into our model and found that RaptorQ is the best candidate to mitigate errors in FSO links.

Estimating the decomposition of predictive information in multivariate systems

2015

In the study of complex systems from observed multivariate time series, insight into the evolution of one system may be under investigation, which can be explained by the information storage of the system and the information transfer from other interacting systems. We present a framework for the model-free estimation of information storage and information transfer computed as the terms composing the predictive information about the target of a multivariate dynamical process. The approach tackles the curse of dimensionality employing a nonuniform embedding scheme that selects progressively, among the past components of the multivariate process, only those that contribute most, in terms of co…

Contribution of virtual reality to functional rehabilitation

2010

Virtual reality has grown immensely. Practical applications for the use of this technology encompass many fields in both engineering science and human science. In the field of medicine, one of the newest fields to benefit from the advances in VR technology, virtual reality has become a major new therapeutic tool not only in medicine and surgery but also for the treatment of psychological disorders and rehabilitation for impaired person. Our research presented in this thesis aims at developing utilities to aid in functional rehabilitation using virtual reality technology. The main research question of our work concerns the effect of virtual metaphors in learning and training human gestures f…

The Problem of Time Arrow in Financial Time Series

According to the efficient market hypothesis, future movements of the market cannot be predicted. This introduces an intrinsic time asymmetry of the financial time series as there are no laws forbidding “predicting” past based on the current market fluctuations. This clear time asymmetry in the basic laws of finance raises a question which we shall be referring to as the problem of time arrow: are there any noticeable statistical differences between forward-in-time and reverse-in-time market data. Majority of the statistical methods used for financial time series are time-symmetric and hence, not usable for our purposes. The first method used in our study is the analysis of the length-distr…

The predictive power of power-laws: An empirical time-arrow based investigation

2022

The efficient market hypothesis forbids any predictability towards future, but there is no such restriction in the case of reversed-looking approaches. We analyze if this asymmetry in non-predictability is reflected in the statistical features of financial time series. Our study is based on the analysis of the length-distribution of periods with high variability, and introduces time-asymmetric modifications of the method which are capable of revealing differences of the time series in forward and reversed time. We show that the future and reversed-looking time-series possess very similar properties, with some features being distinguishable with our method. Our findings give also evidence of…

Timing the US Stock Market Using Moving Averages and Momentum Rules: An Extensive Study

2017

Master's thesis Business Administration BE501 - University of Agder 2017 In this thesis we investigate the performance of moving average and momentum strategies by simulating returns, both in-sample and out-of-sample, while simultaneously taking into account important market frictions. We do so for two stock indices and four stock portfolios, at daily and monthly frequency, in the period from 1928 to 2015. This is carried out in order to examine if the active strategies outperform the passive benchmark on a risk-adjusted basis, and to see if the trading rules pro table when tested in-sample also are pro table out-of-sample. In addition, and for the rst time, we examine the relevance of data…