Switching intentions towards car sharing - Analysis of the relationship with traditional transport modes

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Multivariate small sample tests for two-way designs with applications to industrial statistics

In this paper, we present a novel nonparametric approach for multivariate analysis of two-way crossed factorial design based on NonParametric Combination applied to Synchronized Permutation tests. This nonparametric hypothesis testing procedure not only allows to overcome the shortcomings of MANOVA test like violation of assumptions such as multivariate normality or covariance homogeneity, but, in an extensive simulation study, reveals to be a powerful instrument both in case of small sample size and many response variables. We contextualize its application in the field of industrial experiments and we assume a linear additive model for the data set analysis. Indeed, the linear additive model interpretation well adapts to the industrial production environment because of the way control of production machineries is implemented. The case of small sample size reflects the frequent needs of practitioners in the industrial environment where there are constraints or limited resources for the experimental design. Furthermore, an increase in rejection rate can be observed under alternative hypothesis when the number of response variables increases with fixed number of observed units. This could lead to a strategical benefit considering that in many real problems it could be easier to collect more information on a single experimental unit than adding a new unit to the experimental design. An application to industrial thermoforming processes is useful to illustrate and highlight the benefits of the adoption of the herein presented nonparametric approach

Sol-Gel Synthesis of TiO2 Nanocrystalline Particles with Enhanced Surface Area through the Reverse Micelle Approach

Titania nanocrystalline particles were synthesized by hydrolysis-condensation of titanium tetraisopropoxide in water-in-oil micellar solutions of water/cyclohexane/Triton X-100 system, and the effects of reflux time and water-to-surfactant molar ratio on the particle uniformity, crystallinity, and surface area were studied. Several characterization techniques including TEM and SEM, as well as X-ray diffraction and FT-IR spectroscopy, helium pycnometry, and nitrogen physisorption, were employed to evaluate the particle density and dimensions, crystallite size, surface area value, and the porosity features in the as-prepared condition and also after thermal treatment at 500°C. The results show that all treated samples are dense nanocrystalline anatase particles with BET surface area values over 100 m2·g−1 and primary particle size of 10–15 nm. However, for the as-prepared samples, as the reflux time increases, a better purification of particles from the synthesis environment is resulted, leading to denser and more crystalline powders with smaller particle size and higher BET surface area values culminating in 179 m2·g−1 for 24 hours of refluxing. Moreover, decreasing the water-to-surfactant molar ratio from 10 to 5 and 2 increases the particles surface area to 239 and 224 m2·g−1, respectively, at the expense of slight density and crystallinity degradation and considerable prolongation of surfactant removal step. Supportively, the comparison between photocatalytic activities of as-prepared samples also evidences the effectiveness of reflux time extension on improving the sample features and enhancing their functionality. This study can highlight how the earlier synthesis steps can influence the evolution of the structure of the final products

Analisi dei dati degli ultimi Censimenti generali: le economie e le popolazioni di Bassano del Grappa e della provincia di Vicenza a confronto

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Vulnerabilità di una rete di trasporto. Analisi dell'effetto della variazione della domanda di mobilità mediante un modello Activity-Based

Nella tesi si svolge un'analisi di vulnerabilità di una rete di trasporto. Attraverso un modello Activity-Based, si valuta l'effetto della chiusura di un arco sulla variazione delle caratteristiche degli spostamenti degli utenti. Il modello simula la sequenza di attività giornaliere compiute da ciascun individuo. Per ogni scenario di danno sono stati calcolati opportuni indicatori di importanza degli archi. Infine è stato effettuato un confronto assumendo che la domanda rimanga invariataope

Chapter Nonparametric methods for stratified C-sample designs: a case study

Several parametric and nonparametric methods have been proposed to deal with stratified C-sample problems where the main interest lies in evaluating the presence of a certain treatment effect, but the strata effects cannot be overlooked. Stratified scenarios can be found in several different fields. In this paper we focus on a particular case study from the field of education, addressing a typical stochastic ordering problem in the presence of stratification. We are interested in assessing how the performance of students from different degree programs at the University of Padova change, in terms of university credits and grades, when compared with their entry test results. To address this problem, we propose an extension of the Non-Parametric Combination (NPC) methodology, a permutation-based technique (see Pesarin and Salmaso, 2010), as a valuable tool to improve the data analytics for monitoring University students’ careers at the School of Engineering of the University of Padova. This new procedure indeed allows us to assess the efficacy of the University of Padova’s entry tests in evaluating and selecting future students

Measure of urban accessibility provided by transport services in Turin: a traveller perspective through a mobility survey

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Probing the chemical environment of 3-hydroxyflavone doped ormosils by a spectroscopic study of excited state intramolecular proton transfer

Abstract The spectroscopic properties of 3-hydroxyflavone (3-HF) molecules entrapped in films and in monoliths of sol–gel derived organically modified silicates (Ormosils) xerogels are studied by excitation and fluorescence spectroscopy as a function of the sol–gel precursors used for the synthesis. Different molar ratios of tetraethoxysilane (TEOS), methyltriethoxysilane (MTES) and phenyltriethoxysilane (PTES) as precursors are used for the sol preparation. Emission and excitation spectra in the ultraviolet–visible range and photo-degradation curves as a function of time are collected with a spectrofluorimeter. The 3-hydroxyflavone optical properties change in the different networks, owing to the effects of the chemical environment on the excited state intramolecular proton transfer and to the solubility of the dye molecules in the different sol–gel systems. It turns out that the spectroscopic features can be used to probe the chemical state of the dye molecules microenvironment

Different views of the multivariate ranking problem

Multivariate ranking problems are characterized by the need of ordering C different items according to several different features. The multivariate nature of these problems makes them quite challenging and flexible multivariate statistical techniques are therefore required. In this study we focus on two different scenarios, where we need to rank C different populations. Under the first scenario, preliminary knowledge about the order of the populations is available, while under the second one no information is available. Two solutions, based on the Nonparametric combination (NPC) technique, are proposed to deal with these scenarios and two case studies are adopted to facilitate the comprehension of the methods and to highlights the main differences between the two considered multivariate ranking problems