Search results for " indices"

Reliability and effectiveness of Ellenberg’s indices in checking flora and vegetation changes induced by climatic variations

2001

Two methods are proposed to assess the significance of time-spanned local variations of Ellenberg’s indicator values in floristic and phytosociological data sets respectively. Both methods are based on frequencies and averages of the indicator values within and among data sets. Main goal of proposed methods is to determine the threshold above which the observed variations are to be considered significant. In order to relate the observed floristic variations to recent climatic changes, attention was focused on the Ellenberg’s indices dealing with the main climatic variables: heliophany, temperature and precipitation. Study-cases from Zannone Island (Pontine Archipelago, Mediterranean region)…

Angular Dependency of Hyperspectral Measurements over Wheat Characterized by a Novel UAV Based Goniometer

2015

In this study we present a hyperspectral flying goniometer system, based on a rotary-wing unmanned aerial vehicle (UAV) equipped with a spectrometer mounted on an active gimbal. We show that this approach may be used to collect multiangular hyperspectral data over vegetated environments. The pointing and positioning accuracy are assessed using structure from motion and vary from σ = 1° to 8° in pointing and σ = 0.7 to 0.8 m in positioning. We use a wheat dataset to investigate the influence of angular effects on the NDVI, TCARI and REIP vegetation indices. Angular effects caused significant variations on the indices: NDVI = 0.83–0.95; TCARI = 0.04–0.116; REIP = 729–735 nm. Our analysis high…

Modeling Fire Danger in Galicia and Asturias (Spain) from MODIS images

2014

Forest fires are one of the most dangerous natural hazards, especially when they are recurrent. In areas such as Galicia (Spain), forest fires are frequent and devastating. The development of fire risk models becomes a very important prevention task for these regions. Vegetation and moisture indices can be used to monitor vegetation status; however, the different indices may perform differently depending on the vegetation species. Eight different spectral indices were selected to determine the most appropriate index in Galicia. This study was extended to the adjacent region of Asturias. Six years of MODIS (Moderate Resolution Imaging Spectroradiometer) images, together with ground fire data…

Similarity-Based Virtual Screening to Find Antituberculosis Agents Based on Novel Scaffolds: Design, Syntheses and Pharmacological Assays

2022

A method to identify molecular scaffolds potentially active against the Mycobacterium tuberculosis complex (MTBC) is developed. A set of structurally heterogeneous agents against MTBC was used to obtain a mathematical model based on topological descriptors. This model was statistically validated through a Leave-n-Out test. It successfully discriminated between active or inactive compounds over 86% in database sets. It was also useful to select new potential antituberculosis compounds in external databases. The selection of new substituted pyrimidines, pyrimidones and triazolo[1,5-a]pyrimidines was particularly interesting because these structures could provide new scaffolds in this field. T…

Internal Test Sets Studies in a Group of Antimalarials

2006

Topological indices have been applied to build QSAR models for a set of 20 an- timalarial cyclic peroxy cetals. In order to evalua te the reliability of the proposed linear models leave-n-out and Internal Test Sets (ITS) approaches have b een considered. The pro- posed procedure resulted in a robust and consensued prediction equation and here it is shown why it is superior to the employed standard c ross-validation algorithms involving multilinear regression models.

Dynamique de la structure industrielle française

1990

Three (marginal?) questions regarding convergence

2004

This paper focuses on three (marginal?) questions surrounding the analysis of economic convergence and uses Spanish provinces as a means of illustration. The three questions in hand are the following: (i) given that the geographical units of analysis are usually quite different in economic size, is the weighting of economic units relevant in convergence analysis? (ii) the average per capita income of a given region, or country, is the first moment in the distribution of income, but what about the second moment, inequality? Have we converged in inequality? and (iii) an aggregate welfare index must take into account, at least, the evolution of the first two moments of the distribution of inco…

A Benchmarking Platform for Atomic Learned Indexes

2022

This repository provides a benchmarking platform to evaluate how Feed Forward Neural Networks can be effectively used as index data structures.

A Learned Sorted Table Search Library

2021

This library includes a collection of methods for performing element search in ordered tables, starting from textbook implementations to more complex algorithms

Modified Search on Sorted Data Benchmark for Branchy vs Branchfree study.

2021

The repository contains a modified version of SOSD platform. This is designed to replicate the results presented in our paper at ArXiv concerning the comparison between Branchy and Banchfree algorithms using the best Learned Indexes in the Literature.