Search results for " parametric model"
showing 7 items of 7 documents
Assessment of Granger causality by nonlinear model identification: application to short-term cardiovascular variability.
2007
A method for assessing Granger causal relationships in bivariate time series, based on nonlinear autoregressive (NAR) and nonlinear autoregressive exogenous (NARX) models is presented. The method evaluates bilateral interactions between two time series by quantifying the predictability improvement (PI) of the output time series when the dynamics associated with the input time series are included, i.e., moving from NAR to NARX prediction. The NARX model identification was performed by the optimal parameter search (OPS) algorithm, and its results were compared to the least-squares method to determine the most appropriate method to be used for experimental data. The statistical significance of…
Frequency Domain Information Decomposition: Application to Plateau Waves of Intracranial Pressure
2022
The sustainment and/or resurgence of Plateau Waves (PWs) reveals a borderline cerebral situation of the pressure-volume relationship and is related to increased mortality. The intense systemic stress caused by PWs can be evidenced by the study of Heart Rate Variability (HRV), which is an indicator of the activity of the autonomic nervous system, namely the sympathetic and parasympathetic imbalance. In this work, heart and brain crosstalk interactions will be analyzed using a spectral decomposition of multivariate information measures, which provides frequency-specific quantification of the information shared between a target and two source time series. The spectral measures of information h…
Wedge-shaped bricks spires and domes. Construction and decorative aspects
2018
The use of maiolica bricks as artefact for surface decoration is widespread both in monumental and ordinary architectures in the Mediterranean regions, harmonizing the local construction traditions with the Islamic influences. This study presents an in-depth analysis of examples of spires and domes in Sicily featuring earthenware maiolica cladding serving both as decoration and structural element. Due to the limited knowledge of these artefacts, incautious construction operations led to an alteration of their material and technical features, putting at risk a centuries-old heritage. The systematic investigation on more than a hundred samples categorises these architectural polychrome elemen…
Il mattone cuneiforme maiolicato. Procedure algoritmico-parametriche digitali come strumento di indagine e progettazione: dall'architettura storica a…
2020
The study focuses on the cuneiform in majolica brick that has been widespread in Sicily since the 16th century for the construction of spires and domes. A unifying element that has constituted a particular identity contribution to the island’s brick tradition; an original solution able to combine aesthetics with structural and durability. On the basis of more than a hundred examined cases, the different geometrical-formal peculiarities detected in relation to the characteristics of the shell are described. Some analyses and checks of the traditional geometrical composition patterns of the wall facade are reported. Through the definition of digital tools of algorithmic-parametric design, new…
Digital & Documentation - The new boundaries of digital &documentation - Vol. 4
2022
Elastīgais parametriskais modelis izdzīvošanas datiem ar konkurējošiem riskiem
2015
Konkurējošie riski ir izplatīta parādība izdzīvošanas analīzē. Tie rodas, kad subjekts atrodas vairāku savstarpēji izslēdzošu notikumu riska zonā. Populārākā metode, pētot šāda veida datus, ir Deivida Koksa semi-parametriskā modeļa izmantošana. Darbā ir aplūkots alternatīvais variants izdzīvošanas datiem ar konkurējošiem riskiem – elastīgais parametriskais modelis, kas sniedz gludus novērtējumus galvenajiem raksturlielumiem – konkrēto cēloņu riskam un kumulatīvo biežumu funkcijai. Turklāt, izmantojot šo modeli, ir viegli iekļaut no laika atkarīgus ietekmējošos mainīgos. Darbā tiek aprakstīta konkurējošo risku elastīgā parametriskā modeļa būtība, un metode ir salīdzināta ar Koksa modeli. Ir …
Models Used for Measuring Customer Engagement
2013
The purpose of the paper is to define and measure the customer engagement as a forming element of the relationship marketing theory. In the first part of the paper, the authors review the marketing literature regarding the concept of customer engagement and summarize the main models for measuring it. One probability model (Pareto/NBD model) and one parametric model (RFM model) specific for the customer acquisition phase are theoretically detailed. The second part of the paper is an application of the RFM model; the authors demonstrate that there is no statistical significant variation within the clusters formed on two different data sets (training and test set) if the cluster centroids of t…