Search results for "Tree"
showing 10 items of 1841 documents
Spectral properties of correlation matrices for some hierarchically nested factor models
2007
We show that spectral methods, such as Principal Component Analysis and Random Matrix Theory, are unable to reveal the hierarchical (or nested) structure of a set of mutivariate data. We consider the method introduced in M. Tumminello et al., EPL 78, 30006 (2007) to associate a hierarchical factor model with a set of data by making use of clustering algorithms. This is done by proving the existence of a bijective correspondence between a hierarchical tree and a factor model.
An Encoding in Metaheuristics for the Minimum Communication Spanning Tree Problem
2009
Problem-specific encodings can improve the performance of metaheuristics, such as genetic algorithms or simulated annealing. This paper studies the link-biased (LB) encoding, which is a tree representation, and applies metaheuristics using this encoding to the minimum communication spanning tree (MCST) problem. Given the communication requirements of the nodes, the MCST problem seeks a communication spanning tree with minimum total cost. Optimal solutions for MCST problems are similar to minimum spanning trees (MSTs), and the LB encoding exploits this property by encoding trees similar to MSTs with higher probability. The paper investigates how to systematically design problem-specific enc…
A Comparative Study and an Evaluation Framework of Multi/Hyperspectral Image Compression
2009
In this paper, we investigate different approaches for multi/hyperspectral image compression. In particular, we compare the classic multi-2D compression approach and two different implementations of 3D approach (full 3D and hybrid) with regards to variations in spatial and spectral dimensions. All approaches are combined with a weighted Principal Component Analysis (PCA) decorrelation stage to optimize performance. For consistent evaluation, we propose a larger comparison framework than the conventionally used PSNR, including eight metrics divided into three families. The results show the weaknesses and strengths of each approach.
Monetary Valuations of Monumental Trees and Other Natural Resources between Demand for Conservation and Recent Requirements for Outdoor Activities: S…
2011
The focus of this paper is on the valuation of the benefits that local communities living in protected areas may perceive with regard to some specific natural resources, and in particular to Monumental Trees. The current economic crisis which involves countries at world level, leads to think that in the near future the financial resources to be destined for interventions in favour of these environmental goods will be more and more scarce, with the result that most monumental trees will not be protected and this natural heritage will be totally degraded and therefore lost to local communities. Three Sicilian case studies were investigated, two concerning the Madonie Regional Natural Park, an…
Preliminary evaluation of sixPrunusrootstocks for peach in Italy
2018
In Italy, the evaluation of rootstocks is supported by the Ministry of Agriculture and carried out in a network of trials along the Country. This study evaluated growth and yield performance of ‘Big Top’ nectarine and ‘Rome Star’ peach grafted on six rootstocks of different origin and vigor, namely GF677 (the most widespread in Italy), Garnem, Adesoto, RootPac®20, RootPac®40, and RootPac®90, in three different locations, Castelvetrano (Sicily), Forlì and Cesena (Emilia-Romagna). Yield, number of fruits, trunk cross-sectional area (TCSA), average fruit weight, flesh firmness, soluble solids content (SSC) and titratable acidity (TA) were determined at the third leaf (2015). In all sites, tree…
Proceeding of the International Symposium on the Challenge for a Sustainable Production, Protection and Consumption of Mediterranean Fruit and Nuts -…
2012
Effect of soil permanent grass cover on growth, yield and water status of rainfed olive trees in Sicily
2017
The study was carried out in an olive grove located along the hills of northern Sicily where soil had been managed for decades by chemical weeding. Starting in 2008, one portion of the grove was left non-weeded, and the permanent grass cover was managed by mowing 2-3 times per year in winter and spring. In 2011, 2012 and 2013, yield, average drupe weight, percentage of drupe black color (veraison), trunk circumference, shoot elongation, and leaf relative water content (RWC) were determined on 34 adult trees of the cultivar 'Biancolilla' with uniform size and age. In 2013, soil organic matter content and leaf nutrient concentrations were also determined in the two portions of the grove. As e…
Relationship between canopy architecture and fruit quality on 'Rich May' peach grafted onto 'Penta' and 'GF677' rootstocks
2006
Observations on crop efficiency and fruit quality of peach trees of ‘Rich May’ grafted onto ‘GF677’ (peach x almond) and ‘Penta’ (Prunus domestica L.) rootstocks are reported. Results were related to canopy architecture parameters, particularly to scaffold branches, shoot and leaf blade inclination angles, to the pattern of light distribution, and to the area of sunflecks projected at midday on the ground. Trees grafted onto ‘GF677’ were more vigorous, in terms of trunk cross-sectional area, summer pruning weight and leaf area. Within canopy light distribution profiles were in agreement with foliage density, with a higher light interception observed in trees grafted on ‘GF677’. Within canop…
Propagation techniques and nursery management for the production of certified peach plants in Europe
2022
The propagation of fruit trees, particularly peaches, nectarines and canning clingstone, has reached highly specialized levels since the 1960s. Over the years, the classic seed rootstocks have been replaced by numerous rootstocks produced in vitro, expanding the range of technical solutions for the different soil and climatic growing conditions of several areas. Thanks to the new genotypes from international breeding programs, it was thus possible to renew the cultivated varietal platform several times. Propagation techniques have also undergone an evolution, adopting solutions aimed at shortening nurseries’ production cycles by using June budding or micrografting. Finally, there are differ…