1,721,071 research outputs found
Interval measurements of large volcanic eruptions
No full textPer la difficoltà nell’identificare la magnitudine precisa degli eventi vulcanici,
le eruzioni vengono usualmente registrate tra un valore minimo e uno massimo e
poi, usualmente, se ne cataloga la media. L’obiettivo è quello di capire quali differenze
si possano ottenere, in fase di interpretazione e previsione delle eruzioni vulcaniche, se si
considera l’informazione censurata originaria o le medie degli intervalli
Hierarchical random effect models for coastal erosion of cliffs in the Holderness coast
No full textPrediction of possible cliff erosion at some future date is fundamental to
coastal planning and shoreline management, for example to avoid development in
vulnerable areas. Historically, to predict cliff recession rates deterministic methods
were used. More recently, recession predictions have been expressed in probabilistic
terms. However, to date, only simplistic models have been developed. We consider
the cliff erosion along the Holderness Coast. Since 1951 a monitoring program has
been started in 118 stations along the coast, providing an invaluable, but often missing,
source of information.We build hierarchical random effect models, taking account of
the known dynamics of the process and including the missing information
Erosione della costa di Holderness: costruzione di un modello gerarchico a effetti casuali per dati censurati
Full text linkAn awareness of the possible cliff position at some future date is fundamental to coastal planning and shoreline management, for example to avoid development in vulnerable areas. At the beginning, to predict cliff recession rates deterministic methods have been investigated. Then, recession predictions are being expressed in probabilistic terms. However, so far, only easy models were developed.
We consider the cliff erosion at the Holderness Coast: since 1951 a monitoring program started in 118 stations along the coast, providing an invaluable, but often censored, source of information.
We built hierarchical random effect models, taking account of the known dynamics of the process and including the censored information
Processi di punto parametrici e non parametrici per la modellazione di eventi vulcanici estremi in presenza di censura.
Full text linkExtreme value theory provides a class of models for the behaviour of stochastic processes at extreme levels. Since volcanic eruptions are (at least in a non-scientific sense) extreme events, it might be hoped that there is some role for the extreme value models in the science of volcanology. In this article we explore such a possibility through a particular catalogue of extreme eruptions registered in the last two millennia. The analysis is based on a particular point process characterization of extremes: it takes into account that historical events in the dataset are less likely to have been recorded than recent events and that this effect seems especially pronounced for events of relatively low magnitude. Ignoring these aspects can lead to a biased estimate of extremal behaviour
Bayesian techniques for modelling volcanic processes
No full textExtreme value theory is the branch of statistics inferring extreme
events in random processes. Bayesian estimation in this field offers many advantages.
We use techniques from extreme value theory to estimate by Bayesian
methods the probability distribution of extreme volcanic eruptions that are subject
to a historical recording bias
Extreme Value Methods for Modelling Historical Series of Large Volcanic Magnitudes
No full textVolcanic eruptions are among the most extreme events on Earth and it seems natural to make use of the theory of extreme values to improve understanding of volcanic processes. The dataset we use is a catalogue of large eruptions over the last two millennia, in which the date of occurrence and magnitude are recorded. The dataset is affected by a recording bias, mostly for eruptions of lower magnitude, though this under-recording process largely disappears in the most recent 400 years. Coles and Sparks (2006) modelled these data, via maximum likelihood, using a Poisson process motivated by extreme value theory, with an intensity function that takes into account the recording bias. Nevertheless, the fitted model did not seem entirely consistent with the observed data, since this intensity function does not represent effectively the temporal evolution of the censoring effect in the recording process
The Evaluation of the Process of Cultural Good Consumption for Different Profiles of Consumers. The case of the Scrovegni Chapel.
Full text linkIn this paper, we investigate the cultural, social and emotional elements affecting the satisfaction process of artistic consumption and we look for satisfaction diversity among different visitor profiles. A sample analysis of the visitors to the Scrovegni Chapel by Giotto in Padua was performed through an ordinal logit model, to identify significant items for general satisfaction with the visit, and through a cluster analysis, to depict visitor profiles for artistic goods. The main result of the statistical analysis is that each dimension affects satisfaction while satisfaction itself varies with the different profiles of the consumer of art. This means that the analysis of demand for artistic goods is useful both for management of artistic events in order to find a suitable organization, and for territorial marketing to attract consumers of aesthetic goods
Pleural Mesothelioma: forecsts of the death toll in the area of Casale Monferrato, Italy
No full textIn the city of Casale Monferrato, the largest Italian factory that produced asbestos cement goods was active from 1907 to 1985. As a consequence, asbestos bers scattered in the surrounding area and caused an enormous number of pleural mesotheliomas. Due to the very long latency of this disease, many subjects have not exhibited its symptoms yet. The aim of this paper is to model and predict the future evolution of the number of deaths due to this disease among residents in the area around that city. The model used here is based on a Cellular Automata that is assumed to pass through three steps: exposure, contamination, diagnosis. In that way, forecasts of the future evolution take into account the environmental conditions that changed in time during the last century because of dierent levels in plant activity. The model is fitted to annual diagnosis data starting from 1954 to 2009. Results show that deaths will not end until 2033, and that in the next two decades, at least 479 more subjects will be diagnosed with this disease
The prediction of the death toll of Pleural Mesothelioma in the area of Casale Monferrato - Italy
No full textAsbestos is the main casual factor for pleural mesothelioma (PM). The largest Eternit asbestos-cement factory was active from 1907 to 1985 in Casale Monferrato, in north-western Italy. Only in the last decades, the epidemic of PM began to show its gravity. Traditional studies (APC analysis and Environmental studies) focused on measuring the risk mostly for particular categories of people, and on deducing the corresponding death toll by applying the relative risks to plausible future population scenarios. Mostly the individual exposure history (intensity and duration of exposure) is not included
- …
