Search results for " Cluster analysis"
showing 10 items of 77 documents
Spanning Trees and bootstrap reliability estimation in correlation based networks
2007
We introduce a new technique to associate a spanning tree to the average linkage cluster analysis. We term this tree as the Average Linkage Minimum Spanning Tree. We also introduce a technique to associate a value of reliability to links of correlation based graphs by using bootstrap replicas of data. Both techniques are applied to the portfolio of the 300 most capitalized stocks traded at New York Stock Exchange during the time period 2001-2003. We show that the Average Linkage Minimum Spanning Tree recognizes economic sectors and sub-sectors as communities in the network slightly better than the Minimum Spanning Tree does. We also show that the average reliability of links in the Minimum …
El perfil profesional de los formadores de formación continua en España
2011
El objetivo de este trabajo es analizar y describir los perfiles profesionales del formador de formación continua en España. Con este propósito se ha elaborado un cuestionario estructurado que se ha aplicado de forma presencial a una muestra de 606 formadores a nivel nacional. El cuestionario ha proporcionado información sobre aspectos como el estatus socio-laboral del formador, el grado de profesionalización y la importancia de las competencias profesionales de los formadores. La información recabada ha sido analizada mediante métodos multivariantes para determinar los perfiles profesionales dominantes. El análisis cuantitativo incluye el Análisis de Componentes Principales Categóricos (CA…
Main Trends in Regional Innovation Systems: An Author Co-citation Analysis
2010
Regional Innovation Systems are increasingly attracting attention on behalf of accademics, practitioners and policy makers. This has produced a wide array of studies in the field, both regards the specific themes treated and the perspectives adopted. Though a number of sujective reviews of the field have been proposed, these tend to present the field according to the analysts' subjective biases and tends to meld what the field is with what the field should be. In order to overcome the limitations present in the subjective reviews proposed untill today, in this study we conduct an objective review of the main contributions to the Regional Innovation Systems fiels of studies.
Comparison of Disease Clusters in Two Elderly Populations Hospitalized in 2008 and 2010
2013
<b><i>Background:</i></b> As chronicity represents one of the major challenges in the healthcare of aging populations, the understanding of how chronic diseases distribute and co-occur in this part of the population is needed. <b><i>Objectives:</i></b> The aims of this study were to evaluate and compare patterns of diseases identified with cluster analysis in two samples of hospitalized elderly. <b><i>Methods:</i></b> Data were obtained from the multicenter ‘Registry Politerapie SIMI (REPOSI)' that included people aged 65 or older hospitalized in internal medicine and geriatric wards in Italy during 2008 and 2010. The s…
Impact of clinical phenotypes on management and outcomes in European atrial fibrillation patients: a report from the ESC-EHRA EURObservational Resear…
2021
Abstract Background Epidemiological studies in atrial fibrillation (AF) illustrate that clinical complexity increase the risk of major adverse outcomes. We aimed to describe European AF patients’ clinical phenotypes and analyse the differential clinical course. Methods We performed a hierarchical cluster analysis based on Ward’s Method and Squared Euclidean Distance using 22 clinical binary variables, identifying the optimal number of clusters. We investigated differences in clinical management, use of healthcare resources and outcomes in a cohort of European AF patients from a Europe-wide observational registry. Results A total of 9363 were available for this analysis. We identified three …
Social Housing and Affordable Rent: The Effectiveness of Legal Thresholds of Rents in Two Italian Metropolitan Cities
2022
Social housing is an instrument of housing policies to support those groups of people who are disadvantaged due to particular economic weaknesses and/or social relational fragility. Consequently, to achieve the objective of social sustainability, the rents of social housing must be below the market rents and low enough to be affordable. Italian law has set several rent thresholds which are based on local territorial agreements between landlords and renters associations. This article aims to examine whether these thresholds generate social fairness and housing affordability within each city and between different cities, or instead inequalities and spatial asymmetries. A cluster analysis is a…
Wine and quality. A cluster anlysis to assess certain representative aspects relating to the quality
2009
This research, in which the technique of Cluster Analysis is used, will provide information on how wine producers can evaluate certain characteristics (variables) of their product more widely associated as indicative of quality. The analysis identified homogeneous groups containing within them other, related variables, which can be considered similar. Those attributes which are by themselves most representative of the product's quality are also highlighted. Finally, the cluster analysis made it possible to comment on the behaviour of producers, and looking at how they seek to meet market expectations based on their knowledge of customer's habits in the buying and consuming of wine.
An Inquiry-Based Approach to a Pedagogical Laboratory for Primary School Teacher Education
2017
In questo articolo vengono presentati e di- scussi alcuni risultati relativi alla sperimen- tazione di due esperienze di didattica laboratoriale della fisica, una basata su me- todi di indagine scientifica e l’altra su meto- dologie didattiche più “tradizionali”, svolte durante l’A.A. 2014-15 con studenti del CdL in Scienze della Formazione Primaria del- l’Università di Palermo. I dati, analizzati tra- mite metodi quantitativi, sono stati ricavati dalla somministrazione prima, durante e do- po le attività laboratoriali, di un questionario finalizzato a comprendere gli stili di insegna- mento preferiti dagli studenti, la motivazio- ne di questi all’apprendimento/insegna- mento delle scienze …
Multidimensional Scaling in Cluster Analysis: examples in Science and Mathematics Education
2021
Several researches in STEM education research highlight the advantages of an inte- grated approach to these disciplines that relates knowledge and know-how, design and implementation, theoretical and practical problems [5, 4, 6]. In some researches, the effectiveness of these approaches on students conceptual understanding and motivation and has been studied through the use of quantitative analysis tools such as cluster analysis (CLA) [1, 7]. Through CLA it is possible to characterize students analyzing the strategies they deploy to tackle, for example, questionnaires built so as to investigate the lines of reasoning implemented by them when they are proposed with problematic situations. In…
A Phenomenological Study About the Effect of Covid-19 Pandemic on the Use of Teaching Resources in Mathematics
2023
In this contribution, we discuss phenomenological research related to a pilot study carried out by the Consortium of the MaTeK Horizon 2020 project during the 2020–21 academic year. The research aims to analyse the effects of the Covid-19 pandemic on the use of teaching resources in mathematics in five coun- tries. A questionnaire made of seven questions was administered to a data sample made of teachers of all grades. The answers coming from the questionnaire were quantitatively and qualitatively analysed. Closed-ended questions were analysed by using a clustering methodology called k-means. Open-ended questions were qualitatively analysed. The results show that almost all the teachers are…