Search results for " Correspondence Analysi"
showing 10 items of 44 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.
Study of growth opportunities for Sicilian sparkling wine market by a Simple Correspondence Analysis and a Focus Group
2010
Sicilian territory vocation to the production of wines is a prerequisite needed to ensure a large variety of high quality products, very appreciated by national and international markets. Indeed, Sicily produces sparkling wines since the past century and now there are 21 Sicilian wineries that produce high quality sparkling wines. Currently, Sicilian sparkling wines are sold in the local market, however, customer penetration is still low due to a lack of communication and advertising. This paper is divided in two parts and aims to investigate through an experimental survey, possible growth opportunities for Sicilian sparkling wines market. In the rst part we applied the Simple Correspondenc…
Socio-Demographic Vulnerability: The Condition of Italian Young People
2009
For a kind of inertia effect, today the Italian welfare state protects the older too much and, on the contrary, it does not counter sufficiently the new risks associated with other phases of life. Not much seems to be implemented in favour of Italian young people who, as a matter of fact, seem to suffer a lot from the present changes: young people remain longer in the parental home and postpone setting up their own independent life to a most advanced age. In order to understand the situation of vulnerability increasingly widespread among young people, it seemed more and more necessary an in-depth analysis of the reasons and the subjective status of the discomfort that affects young people b…
Measuring Tourist Satisfaction Through a Dual Approach: The 4Q Methodology
2018
Tourist satisfaction is one of the key factors in determining the success of a tourist destination, since it affects behavioural intentions, such as the willingness to revisit and recommend the destination. Therefore, much research has addressed the measuring of tourist satisfaction, either eliciting positive or negative evaluations of a holiday or destination. The spread between expected positive and negative characteristics can trigger a tourist experience. And the gap between expectations and perceptions will produce a feeling of satisfaction or dissatisfaction (Expectancy-Disconfirmation Paradigm, EDP). Under these conditions, this paper adopts a dual approach, considering tourist satis…
Comparing biological classifications of freshwater phytoplankton: a case study from South China
2012
The use of ecological classification systems is becoming more and more widely used when studying phytoplankton. Grouping phytoplankton species into ecologically coherent groups allow to reduce redundancy and in this way, to handle a minor number of biological variables when investigating the ecological status of aquatic ecosystems. Three ecological classifications are mostly used when freshwater phytoplankton is studied: functional groups or coda, morpho-functional groups (MFGs) and morphology-based functional groups (MBFGs). In this study, these three ecological classifications were comparatively used along with two taxonomic classifications based on species and genera to analyse phytoplan…
Visualizing categorical data in ViSta
2003
The modules in the statistical package ViSta related to categorical data analysis are presented These modules are: visualization of frequency data with mosaic and bar plots, correspondence analysis, multiple correspondence analysis and loglinear analysis. All these methods are implemented in ViSta with a big emphasis on plots and graphical representations of data, as well as interactivity for the user with the system. These provide a system that has shown to be easy, useful, and powerful, both for novice and experienced users.
Multiple factor analysis: principal component analysis for multitable and multiblock data sets
2013
Multiple factor analysis MFA, also called multiple factorial analysis is an extension of principal component analysis PCA tailored to handle multiple data tables that measure sets of variables coll...
Multivariate statistical analysis for exploring road crash-related factors in the Franche-Comté region of France
2021
Understanding and modelling road crash data is crucial in fulfilling safety goals by helping national authorities to take necessary measures to reduce crash frequency and severity. This work aims at giving a multivariate statistical analysis of road crash data from the French region of Franche-Comte with special attention to road crash gravity. The first step for this multivariate analysis was to perform Multiple Correspondence Analysis in order to assess associations between the road crash injury and several important accident-related factors and circumstances. Log-linear models are used next in order to detect associations between road crash severity and related factors such as al-cohol/d…
DEFINING MACROINVERTEBRATE ASSEMBLAGE TYPES OF HEADWATER STREAMS: IMPLICATIONS FOR BIOASSESSMENT AND CONSERVATION
2003
We used data from 235 boreal headwater streams in Finland to examine whether macroinvertebrate assemblages constitute clearly definable types, and how well biologically defined assemblage types can be predicted using environmental variables. Two- way indicator species analysis produced 10 assemblage types, which differed significantly from each other (multiresponse permutation procedure, MRPP). However, based on MRPP and nonmetric multidimensional scaling, there was wide variation among sites within each assemblage type, and high degrees of overlap among assemblage types. Such continuous variation was also evidenced by the low number of effective indicator taxa (indicator value method) for …
Identified Risk Factors Among Truck Drivers Circulating in France
2020
The growth of the European market for road-freight transport has recently led to important changes. Moreover, due to the geographical context of France, truck drivers from different countries circulate on French roads to deliver their goods. Having road safety concerns in mind and based on a literature review, as well as interviews, a French questionnaire has been developed. Aiming at collecting data among truck drivers from different European countries, the questionnaire has been translated into seven languages and has been administered at four highway rest areas in France. The collected data were analyzed by means of multiple correspondence analysis, which pointed out new links between wo…