Search results for " CLUSTER"
showing 10 items of 2162 documents
Fuzzy Smoothed Composition of Local Mapping Transformations for Non-rigid Image Registration
2009
This paper presents a novel method for medical image regis- tration. The global transformation is obtained by composing affine trans- formations, which are recovered locally from given landmarks. Transfor- mations of adjacent regions are smoothed to avoid blocking artifacts, so that a unique continuous and differentiable global function is obtained. Such composition is operated using a technique derived from fuzzy C- means clustering. The method was successfully tested on several datasets; results, both qualitative and quantitative, are shown. Comparisons with other methods are reported. Final considerations on the efficiency of the technique are explained.
Trajectory-based and Sound-based Medical Data Clustering
2022
Challenges in medicine are often faced as interdisciplinary endeav- ors. In such an interdisciplinary view, sonification of medical data provides an additional sensory dimension to highlight often hard- to-find information and details. Some examples of sonification of medical data include Covid genome mapping [5], auditory repre- sentations of tridimensional objects as the brain [4], enhancement of medical imagery through the use of sound [1]. Here, we focus on kidney filtering-efficiency time-evolution data. We consider the estimated glomerular filtration rate (eGFR), the main indicator of kidney efficiency in diabetic kidney disease patients.1 We propose a technique to sonify the eGFR tra…
The Switch to Online Learning during the COVID-19 Pandemic: The Interplay between Personality and Mental Health on University Students
2023
The switching from traditional to online learning during the COVID-19 pandemic was challenging for students, determining an increase in physical and mental health problems. The current paper applied a two-step cluster analysis in a large sample of n = 1028 university students (Mage = 21.10 years, SD = 2.45 years; range: 18–30 years; 78.4% females). Participants responded to an online survey exploring neuroticism, trait/state anxiety, general self-efficacy, academic motivation, fear of COVID-19, the impact of the COVID-19 pandemic on physical and mental health, and the help requests. Results showed two significant clusters of students having a Maladaptive Academic Profile (n = 456; 44.4%) or…
The relation between emotional support, self-concept, and social functioning among school-aged children
2013
The study examined the relations between perceived emotional support from parents and peers, self-concept and social functioning among a sample of school-aged children. The study had three main purposes. Firstly, the study was aimed at evaluating the association between emotional support perceived from parents and peers, and self concept. Secondly, the study was aimed at inquiring the existence of different children’s profiles on the basis of the level of perceived emotional support from parents and peers, and their self-concept. Finally, the study was aimed at exploring any difference that could have emerged in their social functioning. The participants were 270 children (F = 137, M = 133)…
Soft Topographic Map for Clustering and Classification of Bacteria
2007
In this work a new method for clustering and building a topographic representation of a bacteria taxonomy is presented. The method is based on the analysis of stable parts of the genome, the so-called “housekeeping genes”. The proposed method generates topographic maps of the bacteria taxonomy, where relations among different type strains can be visually inspected and verified. Two well known DNA alignement algorithms are applied to the genomic sequences. Topographic maps are optimized to represent the similarity among the sequences according to their evolutionary distances. The experimental analysis is carried out on 147 type strains of the Gammaprotebacteria class by means of the 16S rRNA…
LA COMPETITIVITà AZIENDALE
2014
ITALIANO
Cruise passengers' trajectories at destination. A Dynamic Time Warping approach.
2015
The present work aims at proposing an analysis of cruise passengers trajectories at the destination through Dynamic Time Warping algorithm. Data collected through GPS devices on cruise passengers’ behavior in the port of Palermo are analyzed in order to show similarities and differences among their spatial trajectories at the destination. A cluster analysis is performed in order to identify cruise passengers’ segments based on trajectories’ similarity. Results are of interest from both a methodological perspective related with the analysis of GPS data, and for the management and planning of cruise tourism destinations.
The routes of Southern Italy university students: an explorative analysis
2022
The neoclassical migration approach postulates that different conditions in labour markets among territories are the driving forces behind migration. On the other hand, exponents of the new economics of migration argue that the decision to move is not made at the individual level. Considering migration as the result of a decision taken within a social network helps to explain the so-called chain migration. In this paper, we pay attention to the migratory chain of university students. This work introduces a statistical technique to “classify” migratory chains of students living in Sicily, Sardinia or Apulia, and enrolled in some centre-north regions from 2008 to 2017.
On the role of shock waves in galaxy cluster evolution
1998
Numerical simulations of galaxy clusters including two species -- baryonic gas and dark matter particles --are presented. Cold Dark Matter spectrum, Gaussian statistics and flat universe are assumed. The dark matter component is evolved numerically by means of a standard particle mesh method. The evolution of the baryonic component has been studied numerically by using a multidimensional (3D) hydrodynamical code based on modern high resolution shock capturing techniques. These techniques are specially designed for treating accurately complex flows in which shocks appear and interact. With this picture, the role of shock waves in the formation and evolution of rich galaxy clusters is analyze…
Exploring the role of cosmological shock waves in the Dianoga simulations of galaxy clusters
2021
Cosmological shock waves are ubiquitous to cosmic structure formation and evolution. As a consequence, they play a major role in the energy distribution and thermalization of the intergalactic medium (IGM). We analyze the Mach number distribution in the Dianoga simulations of galaxy clusters performed with the SPH code GADGET-3. The simulations include the effects of radiative cooling, star formation, metal enrichment, supernova and active galactic nuclei feedback. A grid-based shock-finding algorithm is applied in post-processing to the outputs of the simulations. This procedure allows us to explore in detail the distribution of shocked cells and their strengths as a function of cluster ma…