Search results for " CLUSTER"

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…

Hierarchical and non-hierarchical clustering methods to study students algebraic thinking in solving an open-ended questionnaire

2017

The problem of taking a data set and separating it into subgroups, where the members of each subgroup are more similar to each other than they are to members outside the subgroup, has been extensively studied in science and mathematics education research. Student responses to written questions and multiple-choice tests have been characterised and studied using several qualitative and/or quantitative analysis methods. However, there are inherent difficulties in the categorisation of student responses in the case of open-ended questionnaires. Very often, researcher bias means that the categories picked out tend to find the groups of students that the researcher is seeking out. In our contribu…

Palermo 2010 - Underwater seismic monitoring of the epicenter area of the 6 September 2002 Palermo Earthquake

2011

Waveforms clustering of small magnitude earthquakes recorded in the Northern Sicilian offshore: evidence of multiplets

2011

Statistical approach for cavity detection using seismic refraction and electrical resistivity data

2017

To test limitations and effectiveness of seismic tomography when coupled to geoelectrical technique for cavity detection 2D synthetic models were used. Synthetic models were created with different number of cavity and blocks of highly cohesive lithological material (high seismic velocity and resistivity values). A modified version of multiple gradient (Martorana et al., 2016) has been used for electrical sequence. The cluster analysis performed on static units defined by electrical resistivity values, P wave velocities, and seismic density on coincident sections, allowed to interpret subsoil structures. The use of the non-hierarchical clustering algorithm has been chosen because it is less …

La città di Alphabet. Architettura per prosumers.

2021

Attraverso alcuni aspetti salienti dell’ideazione, della produzione e dell’opposizione al progetto del Toronto Quayside di Sidewalk labs, l’articolo discute l’influenza delle infrastrutture digitali per l’informazione sul progetto della casa e del quartiere. L’ampliamento delle attività svolte da remoto nello spazio domestico, enfatizzato dal quotidiano della pandemia da Covid 19, costituisce per gli oligopolisti planetari degli urban data come Alphabet un utile volano pubblicitario e un acceleratore. La fusione dei nuovi vessilli della tecnoemancipazione e della sostenibilità in ipotesi sperimentali che mirano a costruirsi sia per intero che per parti realizza un nuovo orizzonte in cui lo …

Image Segmentation based on Genetic Algorithms Combination

2005

The paper describes a new image segmentation algorithm called Combined Genetic segmentation which is based on a genetic algorithm. Here, the segmentation is considered as a clustering of pixels and a similarity function based on spatial and intensity pixel features is used. The proposed methodology starts from the assumption that an image segmentation problem can be treated as a Global Optimization Problem. The results of the image segmentations algorithm has been compared with recent existing techniques. Several experiments, performed on real images, show good performances of our approach compared to other existing methods.

Dissimilarity Measures for the Identification of Earthquake Focal Mechanisms

2013

This work presents a study about dissimilarity measures for seismic signals, and their relation to clustering in the particular problem of the identification of earthquake focal mechanisms, i.e. the physical phenomena which have generated an earthquake. Starting from the assumption that waveform similarity implies similarity in the focal parameters, important details about them can be determined by studying waveforms related to the wave field produced by earthquakes and recorded by a seismic network. Focal mechanisms identification is currently investigated by clustering of seismic events, using mainly cross-correlation dissimilarity in conjunction with hierarchical clustering algorithm. By…

Speeding up the Consensus Clustering methodology for microarray data analysis

2010

Abstract Background The inference of the number of clusters in a dataset, a fundamental problem in Statistics, Data Analysis and Classification, is usually addressed via internal validation measures. The stated problem is quite difficult, in particular for microarrays, since the inferred prediction must be sensible enough to capture the inherent biological structure in a dataset, e.g., functionally related genes. Despite the rich literature present in that area, the identification of an internal validation measure that is both fast and precise has proved to be elusive. In order to partially fill this gap, we propose a speed-up of Consensus (Consensus Clustering), a methodology whose purpose…

LIFE CYCLE ASSESSMENT-DRIVEN SELECTION OF INDUSTRIAL ECOLOGY STRATEGIES

2010

The paper presents an application of the Life-Cycle Assessment (LCA) to the planning and environmental management of an ‘‘eco-industrial cluster.’’ A feasibility study of industrial symbiosis in southern Italy is carried out, where interlinked companies share subproducts and scraps, services, structures, and plants to reduce the related environmental impact. In particular, the research focuses on new recycling solutions to create open recycling loops in which plastic subproducts and scraps are transferred to external production systems. The main environmental benefits are the reduction of resource depletion, air emissions, and landfilled wastes. The proposed strategies are also economically…