Search results for "Series"

Study of vegetation evolution in Sicily using time series analysis of remote sensing and climatic data.

2007

During last 10 years, several studies confirmed that drought phenomena are affecting southern Mediterranean areas. One of the effects of a persistent drought is a modification of the vegetation cover and biomass. The aim of our research is to investigate and monitor the evolution of this phenom- enon in Sicily using remote sensing techniques. To do this, a data set of NOAA-AVHRR multispectral images, acquired monthly from 1988 to 2005, has been calibrated and processed. A time series analysis (TSA) has been applied both on the NDVI and precipitation data sets in order to study the main characteristics of vegetation distribution during the period under investigation and to compare the vegeta…

Oppimisvaikeuksien arviointi ja tukeminen suomenruotsalaisissa kouluissa ja päiväkodeissa

2015

Malthusian checks in pre-industrial Sweden and Finland: a comparative analysis of the demographic regimes

2015

In this article, the existence of the Malthusian preventive and positive checks in pre-industrial Sweden and Finland are studied using demographic and economic data from circa 1750–1860. By applying time series analysis, we are able to identify strong preventive and positive checks for Sweden. The preventive check is considered to work both directly through births and indirectly through marriages. Although the Finnish data also indicate the existence of the preventive check, the positive check is only detected with differenced data. Our findings contradict the initial hypothesis that, due to poverty, Finland would display a higher sensitivity of mortality to living standards than Sweden. In…

Approximate Taylor methods for ODEs

2017

Abstract A new method for the numerical solution of ODEs is presented. This approach is based on an approximate formulation of the Taylor methods that has a much easier implementation than the original Taylor methods, since only the functions in the ODEs, and not their derivatives, are needed, just as in classical Runge–Kutta schemes. Compared to Runge–Kutta methods, the number of function evaluations to achieve a given order is higher, however with the present procedure it is much easier to produce arbitrary high-order schemes, which may be important in some applications. In many cases the new approach leads to an asymptotically lower computational cost when compared to the Taylor expansio…

Nonlinear Time-Series Adaptation for Land Cover Classification

2017

Automatic land cover classification from satellite image time series is of paramount relevance to assess vegetation and crop status, with important implications in agriculture, biofuels, and food. However, due to the high cost and human resources needed to characterize and classify land cover through field campaigns, a recurrent limiting factor is the lack of available labeled data. On top of this, the biophysical–geophysical variables exhibit particular temporal structures that need to be exploited. Land cover classification based on image time series is very complex because of the data manifold distortions through time. We propose the use of the kernel manifold alignment (KEMA) method for…

Assessing the Beneficial Effects of Economic Growth: The Harmonic Growth Index

2011

In this paper we introduce the multidimensional notion of harmonic growth as a situation of diffused well-being associated to an increase of per capita GDP. We say that a country experienced a harmonic growth if during the observed period all the key indicators, proxies of the endogenous and exogenous forces driving population well-being, show a significantly common pattern with the income dynamics. The notion is operationalized via an index of time series harmony which follows the functional data analysis approach. This Harmonic Growth Index (HGI) is based on comparisons between the coefficients from cubic B-splines interpolation. Such indices are then synthesized in order to provide the g…

Feasibility of Ultra-Short-Term Analysis of Heart Rate and Systolic Arterial Pressure Variability at Rest and during Stress via Time-Domain and Entro…

2022

Heart Rate Variability (HRV) and Blood Pressure Variability (BPV) are widely employed tools for characterizing the complex behavior of cardiovascular dynamics. Usually, HRV and BPV analyses are carried out through short-term (ST) measurements, which exploit ~five-minute-long recordings. Recent research efforts are focused on reducing the time series length, assessing whether and to what extent Ultra-Short-Term (UST) analysis is capable of extracting information about cardiovascular variability from very short recordings. In this work, we compare ST and UST measures computed on electrocardiographic R-R intervals and systolic arterial pressure time series obtained at rest and during both post…

Single-Center Retrospective Series of Intracranial Aneurysms Treated with the Barricade Coil System: Immediate and Six-Month Results

2020

Abstract Intracranial aneurysms (IAs) are most commonly found at the branch points of large arteries that form the circle of Willis. The prevalence of IAs in the adult population is 1–5%. IAs rupture is associated with subarachnoid haemorrhage (SAH) in 6–8 cases per 100 000 population, causing mortality in 40–50%. Aneurysm treatment is used to prevent rupture or rebleeding (for ruptured IAs). Randomised trials demonstrated the superiority of endovascular treatment (EVT) of ruptured aneurysms with coil systems over surgery. The objective of the study was to evaluate the effectiveness of the Barricade coil system in the treatment of intracranial aneurysms. Detachable platinum coils, since the…

Prese urbane. Studi di enunciazioni cittadine

2017

Distinguished and diverse theorists such as Benveniste, Barthes, De Certeau and Lotman have each approached the city in different ways. But while several key differences exist between them, their points of view intertwine around the concept of urban enunciation and intersect at differing points. In this study, the positions of these authors will be presented, compared and elaborated upon and the categories of linguistic enunciation of urban space will be set out, drawing from a vision of translation between languages that frequently leads, as is so often the case in Semiotics, to productive analytical models. The linguistic signs of the city will also be illustrated by examples of "short fo…

Iz opyta raboty nad učebnym kompleksom "Vsë prosto!"

2016

The article presents the comments of the authors of the textbook series "Vsye Prosto!" ("Everything Is Easy!") on ways of meeting the challenges related to teaching the Russian language at the initial stage. In particular, it involves the introduction of the Russian alphabet, ways of explaining assignments, monitoring achievements and evaluation, as well as the presentation of cross-cultural materials.