755 research outputs found
Gli strumenti per la scoperta del comportamento di acquisto: la segmentazione della clientela basata sui dati di carta fedeltà
No full textIl lavoro di ricerca presentato nel capitolo mira a sviluppare una metodologia adatta a rappresentar ela composizione della clientela di un'insegna commerciale moderna caratterizzandola sotto il profilo di alcuni comportamenti di acquisto di interesse per il marketing dell'insegna stessa e secondariamente dei fornitori. Una metodologia che superi i limiti e tragga gli elementi migliori dagli approcci finora disponibili e sia praticabile con le risorse e competenze di una impresa commerciale non necessariamente di grandi dimensioni e appartenente al gruppo strategico della Grande Distribuzione, ma più vicina alla realtà distributiva del nostro paese, fatto di imprese di minori dimensioni e appartenenti alla distribuzione organizzata. Il lavoro è frutto di uno sforzo congiunto allo scopo di fornire una sintesi del lavoro scientifico realizzato dagli autori come segue: ZILIANI C., CERIOLI A (2007). La mappa degli stili di acquisto. Un approccio alla segmentazione della clientela basato sui dati di carta fedeltà. MERCATI E COMPETITIVITÀ (ISSN:1826-7386). 61- 82.
Statistical models and the Benford hypothesis: a unified framework
No full textThe Benford hypothesis is the statement that a random sample is made of realizations of an absolutely continuous random variable distributed according to Benford’s law. Its potential interest spans over many domains such as detection of financial frauds, verification of electoral processes and investigation of scientific measurements. Our aim is to provide a principled framework for the statistical evaluation of this statement. First, we study the probabilistic structure of many classical univariate models when they are framed in the space of the significand and we measure the closeness of each model to the Benford hypothesis. We then obtain two asymptotically equivalent and powerful tests. We show that the proposed test statistics are invariant under scale transformation of the data, a crucial requirement when compliance to the Benford hypothesis is used to corroborate scientific theories. The empirical advantage of the proposed tests is shown through an extensive simulation study. Applications to astrophysical and hydrological data also motivate the methodology. © 2023, The Author(s)
Hierarchical latent variable models for dimensionality reduction: an application on composite indicators
No full textThis thesis is devoted to the development of new hierarchical latent variable models for Dimensionality Reduction with a specific focus on the construction of Composite Indicators (CIs). Since our society is producing a huge quantity of data, the construction of model-based CIs represents an interesting and still open methodological challenge. This dissertation is motivated by the necessity to provide model-based CIs which are built according to a statistical approach avoiding subjective choices (e.g., normative weights), therefore, the new insights and proposals hope to represent a contribution to the current literature. This thesis provides an introduction to CIs, a brief review of the most used methods in Multidimensional Data Analysis framework, a discussion about measurement models and methodological proposals to model latent concepts. Factor Analysis and its hierarchical extensions have been introduced in order to set the starting point of the analysis. A first proposal represents a new latent factor model that could be used for building CIs, it aims to investigate the hierarchical structure of the data in order to define two levels of CIs. The model, named Hierarchical Disjoint Non-Negative Factor Analysis is composed of two novelties: a model which is the two level hierarchical extension of FA and its disjoint extension with non-negative loadings. The latter model is enriched by considerations about the CIs used for tracking coherent policy conclusions. A set of features, properties and rules useful to build "good" CIs have been presented and explained. The last proposal in the thesis represents a new model for positive data correlation matrices which aims to detect reliable concepts and to build the hierarchy from them to the most general one. The proposed models are illustrated both via simulation studies and real data applications, to analyze their performances and abilities. In particular, the main application in this thesis regards the construction of a hierarchically aggregated index for the multidimensional phenomenon Waste Management in European Union. Waste Management is becoming even more important for its impact on human-being's lives, and many data have been produced about it, therefore the construction of a CI able to reduce its dimensionality and to highlight the main dimensions of it has a extraordinary usefulness in order to provide support to EU countries' action and policies
Fatto giuridico "civile" e fatto giuridico "religioso": qualificazione statuale e indipendenza confessionale
No full textError rates for multivariate outlier detection
No full textMultivariate outlier identification requires the choice of reliable cut-off points for the robust distances that measure the discrepancy from the fit provided by high-breakdown estimators of location and scatter. Multiplicity issues affect the identification of the appropriate cut-off points. It is described how a careful choice of the error rate which is controlled during the outlier detection process can yield a good compromise between high power and low swamping, when alternatives to the Family Wise Error Rate are considered. Multivariate outlier detection rules based on the False Discovery Rate and the False Discovery Exceedance criteria are proposed. The properties of these rules are evaluated through simulation. The rules are then applied to real data examples. The conclusion is that the proposed approach provides a sensible strategy in many situations of practical interest. © 2010 Elsevier B.V. All rights reserved
(Non)conclusioni: tre questioni su minoranze e laicità positiva negli attuali anni Venti
No full textClosing a debate on religious minorities, the Author poses three central issues for further investigation: the notion of minority itself, the politicisation of relations between the State and religious denominations and the contemporary evolution of positive "laicita
L’ICT nella Pubblica Amministrazione: un’ applicazione ai comuni dell’ Emilia Romagna
No full textIn questa nota si affronta il problema della classificazione delle iniziative di e-government intraprese dai comuni dell’Emilia-Romagna. A tale scopo sono analizzate le informazioni rilevate attraverso un questionario ad hoc predisposto dalla Regione Emilia-Romagna
Additive regression modelling for zero inflated Poisson distribution
No full textin S. Zani and A. Cerioli (Eds
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