1,721,013 research outputs found
Wine authenticity assessed via trimming
No full textAn authentic food is one that is what it claims to be. Consumers and
food processors need to be assured they receive exactly the specific product they pay
for. To ascertain varietal genuinity and distinguish doctored food, in this paper we
propose to employ a robust mixture estimation method. It has been shown to be a
valid tool for food authenticity studies, when applied to food data with unobserved
heterogeneity, to classify genuine wines and identify low proportions of observations
with different origins. Our methodology models the data as arising from a mixture of
Gaussian factors and employ a threshold on the multivariate density to bring apart the
less plausible data under the fitted model. Simulation results assess the effectiveness
of the proposed approach and yield very good misclassification rates when compared
to analogous methods
Socio-economic evaluation with ordinal variables: integrating counting and POSET approaches
Full text linkThe evaluation of material deprivation, quality of life and well-being very often requires to deal with multidimensional systems of ordinal variables, rather than with classical numerical datasets. This poses new statistical and methodological challenges, since classical evaluation tools are not designed
to deal with this kind of data. The mainstream evaluation methodologies generally follow a counting approach, as in a recent proposal by Alkire and Foster pertaining to the evaluation of multidimensional poverty. Counting procedures are inspired by the composite indicator approach and share similar drawbacks with it, computing aggregated indicators that may be poorly reliable.
A recent and alternative proposal is to address the ordinal evaluation problem through partial order theory which provides tools that prove more consistent with the discrete nature of the data. The goal of the present paper is thus to introduce the two proposals, showing how the evaluation methodology based on partial order theory can be integrated in the counting approach of Alkire and Foster
Monitoring tools for robust estimation of cluster weighted models = Strumenti di monitoring per la stima robusta del modello Cluster Weighted
Full text linkNella stima robusta di un cluster weighted model, lo statistico deve fare
molte scelte: specificare la forma dei cluster nelle variabili esplicative, assumere
(o meno) varianza uguale per gli errori nelle linee di regressione e impostare i va-
lori degli iper-parametri per la stima robusta, per evitare la distorsione generata
da valori anomali e contaminazione. L’iper-parametro pi`u delicato da specificare
`e la percentuale di trimming, ovvero la quantit`a di dati da escludere nella stima
per garantirne l’affidabilit`a. In questo lavoro introduciamo specifici strumenti dia-
gnostici per aiutare il professionista, o lo scienziato che ha bisogno di classificare
i dati, a compiere una scelta ragionata a riguardo di tale iper-parametro, anche in
base ad una prima esplorazione dello spazio delle soluzioni.In a robust approach to model fitting for the cluster weighted model, many choices are to be made by the statistician: specifying the shape of the clusters in the explanatory variables, assuming (or not) equal variance for the errors in the re- gression lines, and setting hyper-parameter values for the robust estimation to be protected from outliers and contamination. The most delicate hyper-parameter to specify is perhaps the percentage of trimming, or the amount of data to be excluded from the estimate, to ensure reliable inference. In this work we introduce diagnos- tic tools to help the professional, or the scientist who needs to group the data, to make an educated choice about this hyper-parameter, after a first exploration of the resulting model space
Tra letteratura e politica. L’Incidente di Gaoxiong e la letteratura carceraria a Taiwan tra la fine degli anni Settanta e l’inizio degli anni Ottanta
No full textIn the recent history of Taiwan, the Formosa Incident (also known as Gaoxiong Incident) is generally regarded as one of the pivotal event that led to the process of democratization of the island. On 10 December 1979 an unauthorized demonstration, organized by opponents of the KMT government, took place in the city of Gaoxiong for the celebration of the Human Right Day. The protest ended up with clashes among demonstrators and the KMT military police, and many of the opposition leaders had been eventually arrested. This event and its aftermath left a deep impression on the Taiwanese society as well as on the literary field. In the context of the socalled prison literature (yuzhong wenxue), the Formosa Incident has been a source of inspiration
for both writers and lawmakers directly involved with those circumstances. With a main focus on the literary field, it will be pointed out the outmost relevance of Formosa Incident’s related works
by Yang Qingchu, Wang Tuo and Shi Mingzheng. Apart from the clear contribution of their writings, it will be furthermore examined the way those works influenced the evolution of their literary style, the significance they have in the authors’ main output as well as their relevance in the history of contemporary Taiwanese literature
Predicting and improving smart mobility: a robust model-based approach to the BikeMi BSS = Prevedere e migliorare la mobilita smart: un approccio robusto di classificazione applicato a BikeMi
Full text linkI sistemi di Bike Sharing giocano un ruolo centrale nella mobilita sosteni- ` bile, uno dei sei pilastri che indentificano una Smart City. Motivati da un set di dati disponibile online, questo lavoro presenta l’utilizzo di due modelli di classificazione robusta per prevedere il manifestarsi di situazioni in cui una bike station sia piena e/o vuota, cos`ı creando perdita di domanda ed insoddisfazione nei clienti. Esperimenti di classificazione sulle stazioni BikeMi nel centro di Milano evidenziano l’efficacia dei metodi proposti.Bike Sharing Systems play a central role in what is identified to be one of the six pillars of a Smart City: smart mobility. Motivated by a freely available dataset, we discuss the employment of two robust model-based classifiers for pre- dicting the occurrence of situations in which a bike station is either empty or full, thus possibly creating demand loss and customer dissatisfaction. Experiments on BikeMi stations located in the central area of Milan are provided to underline the benefits of the proposed methods
Cylindrical hidden Markov fields
No full textCylindrical hidden Markov fields are proposed as a parsimonious strategy to analyze spatial cylindrical data, i.e. bivariate spatial series of angles and intensities. These models are mixtures of copula-based bivariate densities, whose parameters vary across space according to a latent Markov random field. They enable segmentation of spatial cylindrical data within a finite number of latent classes that represent the conditional distributions of the data under specific environmental conditions, simultaneously accounting for spatial auto-correlation
Words from abroad in China: past, present and future
No full textSince the half of the twentieth century and still in the first decade of the twenty-first century, a heated debate has been going on in China about borrowings in Chinese lexicon; the peaks of this debate were reached during the 1950s and in the last ten years. In order to understand the features of such long-lasting debate, the analysis of the contents of a number of articles and of monographs dealing with borrowings in Chinese academic and non-academic journals and magazines appeared in both the above-mentioned spans of time has sketched the lines of the debating parties; a brief review of relevant official acts and statements has pointed out the lines of intervention of the State. It turned out that a persistent opposition is contrasting more and more overtly language purists and language pragmatists; Chinese government is trying to mediate between the two parties, but the latest acts indicate that the full-fledged domestic language policy, implemented by the PRC, is leaning towards a standardization and the consequent reduction of
the number of borrowings in Chinese lexicon
Parole per mangiare : Dizionari multilingue per Expo 2015
No full text“Words for eating” is a terminology and lexicolgraphy project launched by the research group of the Department of Studies in Language Mediation and Intercultural Communication of Milan University. The aim is to provide an active and scientific contribution to Expo 2015, by means of the creation of two multilingual terminology dictionaries: Voca3, a practical paper dictionary in Italian-English-Chinese, and Voca8, a specialized online database in eight languages. Four main subthemes have been pinpointed: biotechnology, food preparation, nutrition, food safety. Manifold methods, within the scope of domain-specific Chinese, have been applied: adoption of an onomasiological approach, selection of corpora and objectives, accurate analysis of wordlists, identification of equivalences in Italian-English-Chinese. A critical examination of diverse terminology repertoires and cultural-conceptual schemes, as well as the development of translation strategies to render non-specialized terms absent in Chinese, have been essential to the achievements of this research project
CLUSTERING TWO-MODE BINARY NETWORK DATA WITH OVERLAPPING MIXTURE MODEL AND COVARIATES INFORMATION
No full textBivariate semi-parametric mixed-effects models for classifying the effects of Italian classes on multiple student achievements
No full textWe propose a bivariate semi-parametric mixed-effects model where the
random effects are assumed to follow a discrete distribution with an unknown number
of support points, together with an Expectation-Maximization algorithm to estimate
its parameters - the BSPEM algorithm. This model for hierarchical data can be ap-
plied in many multivariate classification p roblems a nd e nables t he i dentification of
subpopulations within the higher level of the hierarchy. In the case study, we ap-
ply the BSPEM algorithm to data about Italian middle schools, considering students
nested within classes, and we identify subpopulations of classes that have different
class effects on reading and mathematics student achievements
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