Search results for " Trees"
showing 10 items of 214 documents
Dendrolatrie. Miti e pratiche dell'immaginario arboreo
2021
L’avvento dell’Antropoce, epoca in cui l’essere umano è diventato una forza geologica, scompagina la divisione del sapere tra scienze umane e naturali. Per comprenderlo, è necessario costruire nuove forme di alleanza tra discipline. È quanto invita a fare anche il fe- nomeno delle dendrolatrie. Diffuso in ogni luogo e in ogni epoca, il culto degli alberi testimonia come il mondo arboreo abbia plasma- to modi di vivere e di pensare, venendone a sua volta trasformato. Per scavare nella complessità di questo scambio, il volume racco- glie i frutti del dialogo tra un gruppo interdisciplinare di ricercatrici e ricercatori che esplorano l’immaginario arboreo in tre direzioni: quella degli studi s…
[Deciding in conditions of uncertainty: the Delphi method and its use in the formulation of guidelines].
2001
The purpose of this paper is to analyze one of the most powerful tools in the decision-making under conditions of uncertainty, the Delphi method, and to verify the related interest of scientific world, particularly, for formulation of guidelines. The method combines the expert opinion preventing biases due to institutional role, status or dominant personality. In the text we explain the methodology and the steps through which it is possible to realize the consensus; we schematized in a didactic manner all the phases for an operational approach of the reader. The search by the most diffused biomedical database (Medline) individualized 623 citations, 7 of which are guidelines (3 of remarkable…
Evaluation of Risk Parameters in Bone Regeneration Using a Customized Titanium Mesh
2019
PURPOSE The aim of the study was an evaluation of risk factors for an innovative bone regeneration technique using a customized titanium mesh that was tested in a clinical setting. MATERIALS AND METHODS This retrospective study included 65 patients with 70 grafting procedures of osseous defects of the jaws with a customized titanium mesh together with Advanced- and Injectable-Platelet-Rich Fibrin (A- and I-PRF), resorbable membranes, and bone grafting materials. Exposures of the meshes and grafting outcome were analyzed according to a novel classification as (a) punctual and (b) tooth width or complete exposure of the mesh (c). No exposure was stated as (d). RESULTS In 37% of cases, exposur…
Pruning Incremental Linear Model Trees with Approximate Lookahead
2014
Incremental linear model trees with approximate lookahead are fast, but produce overly large trees. This is due to non-optimal splitting decisions boosted by a possibly unlimited number of examples obtained from a data source. To keep the processing speed high and the tree complexity low, appropriate incremental pruning techniques are needed. In this paper, we introduce a pruning technique for the class of incremental linear model trees with approximate lookahead on stationary data sources. Experimental results show that the advantage of approximate lookahead in terms of processing speed can be further improved by producing much smaller and consequently more explanatory, less memory consumi…
Networks of equities in financial markets
2004
We review the recent approach of correlation based networks of financial equities. We investigate portfolio of stocks at different time horizons, financial indices and volatility time series and we show that meaningful economic information can be extracted from noise dressed correlation matrices. We show that the method can be used to falsify widespread market models by directly comparing the topological properties of networks of real and artificial markets.
Weighted distance-based trees for ranking data
2017
Within the framework of preference rankings, the interest can lie in finding which predictors and which interactions are able to explain the observed preference structures, because preference decisions will usually depend on the characteristics of both the judges and the objects being judged. This work proposes the use of a univariate decision tree for ranking data based on the weighted distances for complete and incomplete rankings, and considers the area under the ROC curve both for pruning and model assessment. Two real and well-known datasets, the SUSHI preference data and the University ranking data, are used to display the performance of the methodology.
Local bandwidth selection for kernel density estimation in a bifurcating Markov chain model
2020
International audience; We propose an adaptive estimator for the stationary distribution of a bifurcating Markov Chain onRd. Bifurcating Markov chains (BMC for short) are a class of stochastic processes indexed by regular binary trees. A kernel estimator is proposed whose bandwidths are selected by a method inspired by the works of Goldenshluger and Lepski [(2011), 'Bandwidth Selection in Kernel Density Estimation: Oracle Inequalities and Adaptive Minimax Optimality',The Annals of Statistics3: 1608-1632). Drawing inspiration from dimension jump methods for model selection, we also provide an algorithm to select the best constant in the penalty. Finally, we investigate the performance of the…
Variable Length Memory Chains: Characterization of stationary probability measures
2021
Variable Length Memory Chains (VLMC), which are generalizations of finite order Markov chains, turn out to be an essential tool to modelize random sequences in many domains, as well as an interesting object in contemporary probability theory. The question of the existence of stationary probability measures leads us to introduce a key combinatorial structure for words produced by a VLMC: the Longest Internal Suffix. This notion allows us to state a necessary and sufficient condition for a general VLMC to admit a unique invariant probability measure. This condition turns out to get a much simpler form for a subclass of VLMC: the stable VLMC. This natural subclass, unlike the general case, enj…
MODERATE DEVIATION PRINCIPLES FOR BIFURCATING MARKOV CHAINS: CASE OF FUNCTIONS DEPENDENT OF ONE VARIABLE
2021
The main purpose of this article is to establish moderate deviation principles for additive functionals of bifurcating Markov chains. Bifurcating Markov chains are a class of processes which are indexed by a regular binary tree. They can be seen as the models which represent the evolution of a trait along a population where each individual has two offsprings. Unlike the previous results of Bitseki, Djellout \& Guillin (2014), we consider here the case of functions which depend only on one variable. So, mainly inspired by the recent works of Bitseki \& Delmas (2020) about the central limit theorem for general additive functionals of bifurcating Markov chains, we give here a moderate deviatio…
Contributed discussion on article by Pratola
2016
The author should be commended for his outstanding contribution to the literature on Bayesian regression tree models. The author introduces three innovative sampling approaches which allow for efficient traversal of the model space. In this response, we add a fourth alternative.