Search results for " regression model"
showing 10 items of 41 documents
Segmenting customers according to online word-of-mouth about hotels
2021
There is a renewed interest in the study of online word-of-mouth behavior due to the increasing use of the Internet and the development of social networks. This paper focuses on the receiver perspective to analyze the unequal influence of the antecedents of online consumer searches. The main purpose is to detect the heterogeneity of the effect of different motivations (convenience, risks reduction and social reassurance) and the volume of comments on the willingness to check online reviews. Based on 393 guests of hotels, a mixture regression model indicates the existence of three internally consistent segments, which reveal the varying influence on consumer intentions to look at online comm…
How do normalization schemes affect net spillovers? A replication of the Diebold and Yilmaz (2012) study
2019
Abstract This paper replicates the Diebold and Yilmaz (2012) study on the connectedness of the commodity market and three other financial markets: the stock market, the bond market, and the FX market, based on the Generalized Forecast Error Variance Decomposition, GEFVD. We show that the net spillover indices (of directional connectedness), used to assess the net contribution of one market to overall risk in the system, are sensitive to the normalization scheme applied to the GEFVD. We show that, considering data generating processes characterized by different degrees of persistence and covariance, a scalar-based normalization of the Generalized Forecast Error Variance Decomposition is pref…
On the semi-automatic retrieval of biophysical parameters based on spectral index optimization
2014
Abstract: Regression models based on spectral indices are typically empirical formulae enabling the mapping of biophysical parameters derived from Earth Observation (EO) data. Due to its empirical nature, it remains nevertheless uncertain to what extent a selected regression model is the most appropriate one, until all band combinations and curve fitting functions are assessed. This paper describes the application of a Spectral Index (SI) assessment toolbox in the Automated Radiative Transfer Models Operator (ARTMO) package. ARTMO enables semi-automatic retrieval and mapping of biophysical parameters from optical remote sensing observations. The SI toolbox facilitates the assessment of biop…
Assessing mental health therapeutic communities functioning
2019
Empirical and clinical evidence shows that therapeutic communities produce changes in people’s mental health and well-being. Treatment in communities has effects on improving interpersonal relationships, acceptance among members, ability to recognize other people’s feelings, symptomatology, life satisfaction and self-esteem. This paper aims to investigate which factors can explain the treatment effectiveness, measured by an index which incorporates the point of view of the communities staff members, by means of a beta regression model with random intercept. The results show the influence of some organizational dimension as well as staff roles, providing a meaningful insights into the functi…
A penalized approach to covariate selection through quantile regression coefficient models
2019
The coefficients of a quantile regression model are one-to-one functions of the order of the quantile. In standard quantile regression (QR), different quantiles are estimated one at a time. Another possibility is to model the coefficient functions parametrically, an approach that is referred to as quantile regression coefficients modeling (QRCM). Compared with standard QR, the QRCM approach facilitates estimation, inference and interpretation of the results, and generates more efficient estimators. We designed a penalized method that can address the selection of covariates in this particular modelling framework. Unlike standard penalized quantile regression estimators, in which model selec…
Marginal hazard ratio estimates in joint frailty models for heart failure trials
2019
Abstract This work is motivated by clinical trials in chronic heart failure disease, where treatment has effects both on morbidity (assessed as recurrent non‐fatal hospitalisations) and on mortality (assessed as cardiovascular death, CV death). Recently, a joint frailty proportional hazards model has been proposed for these kind of efficacy outcomes to account for a potential association between the risk rates for hospital admissions and CV death. However, more often clinical trial results are presented by treatment effect estimates that have been derived from marginal proportional hazards models, that is, a Cox model for mortality and an Andersen–Gill model for recurrent hospitalisations. …
Sparse relative risk regression models
2020
Summary Clinical studies where patients are routinely screened for many genomic features are becoming more routine. In principle, this holds the promise of being able to find genomic signatures for a particular disease. In particular, cancer survival is thought to be closely linked to the genomic constitution of the tumor. Discovering such signatures will be useful in the diagnosis of the patient, may be used for treatment decisions and, perhaps, even the development of new treatments. However, genomic data are typically noisy and high-dimensional, not rarely outstripping the number of patients included in the study. Regularized survival models have been proposed to deal with such scenarios…
Relationship Between Extreme Rainfall and Surface Temperature in Sicily (Italy)
2018
The study of the relationship between extreme rainfall events and surface temperature represents an important issue in hydrology and meteorology and it could be of capital importance for evaluating the effect of global warming on future precipitation. Various approaches have been tested across different parts of the world, and, in many cases, it has been observed an intensification of precipitation with increasing temperature consistently with the thermodynamic Clausius-Clapeyron relation (CC-rate of 6-7% °C-1), according to which a warmer atmosphere is capable of holding more moisture. Nevertheless, in different locations, the scaling rate between temperature and extreme precipitation has …
Ranking world tourist destinations with a composite indicator of competitiveness: To weigh or not to weigh?
2019
Abstract This paper contributes a weighted composite indicator of competitiveness for 136 world tourist destinations. To that end, Data Envelopment Analysis and Multi-Criteria-Decision-Making techniques are used with raw indicators from the 2017 edition of the Travel & Tourism Competitiveness Report of the World Economic Forum (WEF). An outstanding feature of our approach is that weights are endogenously generated. Furthermore, the role played by several variables in tourism competitiveness is assessed using truncated regression and bootstrapping. The ranking of world tourist destinations produced by our weighted composite indicator of competitiveness is, however, fairly similar to that der…
Climate variability, innovation and firm performance: evidence from the European agricultural sector
2021
Abstract It is generally accepted that adaptation to climate variability requires a technological advancement strategy. However, the innovation process has received little explicit consideration in this framework. We employ a panel endogenous switching regression model to explore whether and to what extent climate variability affects firm performance through the ability to induce the development of adaptation innovations in key resource-based sectors in Europe during the period 2007–2017. Our findings confirm that the knowledge generation process at the heart of climate change adaptation technologies enhances firm performance, especially for firms in the aquaculture and fishing sub-sectors …