1,721,059 research outputs found
Siepi, qualità del paesaggio e reddito agricolo: la ricerca di soluzioni di compromesso tramite la Goal Programming
No full textI costi sociali dell’uso ricreativo della montagna: venticinque anni di Soccorso Alpino nel Trentino
No full textThe willingness to pay for the conservation of mountain landscape in Cortina d'Ampezzo (Italy)
No full textDestination choice models for rock climbing in the Northeastern Alps: a latent-class approach based on intensity of preference
No full textRock climbers are likely to exhibit
preference heterogeneity dictating the way with
which such sport is practiced. This has a reflection
on the population’s structure of recreational values
of rock-climbing destinations, their attributes, and
to land management policies. We test this hypothesis
on a panel of destination choices by a sample
of members of the Italian Alpine Club. Using a
latent-class, random utility approach we find evidence
in support of the hypothesis that there are
at least four classes in the sample, thereby revealing
a considerable richness in the structure of preference,
which would otherwise be unobservable with
more conventional approaches
: A Monte Carlo Evaluation
Full text linkThe logit-mixed logit (LML) model advances choice modeling by generalizing previous parametric and semi-nonparametric specifications and allowing retrieval of flexible taste distributions. Using standard operating conditions in the field, we report results from Monte Carlo experiments designed to assess the finite sample bias-variance tradeoff for the LML using as a benchmark conventional Mixed logit models (MXL) under asymmetric and multimodal taste distributions. The LML specification always outperforms the MXL in terms of bias, but when the variance around modes is high the mean squared error (MSE) is lower than that of MXL only at sample sizes larger than usual and with some nuances. D-error minimizing experimental design predicated on multinomial logit significantly reduces MSE, but no clear winner is found between polynomial, step, and spline functions for the multidimensional grid function. Analysis of empirical data from a choice experiment on tap water shows that multimodality emerges only if higher number of node parameters are used in the LML
Scale and taste heterogeneity in the case of an unfamiliar good as biodiversity: does the modelling approach of serial nonparticipation affect results?
No full textSerial non-participation is a response behavior that is frequently found in stated choice experiments. One form of serial non- participation is that a varying number of respondents chooses always the zero-price or status quo alternative. The approaches used in the literature to deal with this problem vary from excluding those respondents to using applying latent class models to endoge- nously allow for different preference structures. However, latent class models also allow to assign respondents to a known class. In this paper we compare specifications of latent class models with and without restrictions. Additionally, we control for differences in the error variance across respondents by applying a scale-extended latent class model. The comparisons are designed to show whether respondents are allocated differently among classes and whether willingness to pay estimates are affected significantly. The data are from a choice experiment regarding management actions to enhance forest biodiversity. The data set is characterized by a high percentage of respondents who were not willing to pay; almost 50% of the respondents always chose the zero price alternative locating this sample rather at the top of the range of respondents who are not willing to pay
Investigating determinants of choice and predicting market shares of renewable-based heating systems under alternative policy scenarios
Full text linkFostering the uptake of heating technologies based on renewable resources is an important part of the EU energy policy. Yet, despite e!orts to promote their dif-fusion, heating systems based on fossil fuels are still predominant. In order to better tailor energy policies to citizens preferences, it is crucial to collect accurate informa-tion on their determinants of heating choices. At this purpose, we adopted a choice experiment and a latent class model to analyze preferences of householders in the Veneto region (North-East Italy) for di!erent heating systems and their key features. We focused on three devices based on biomass and three on fossil fuels, and account-ed for technical, economic and environmental characteristics of such systems. Model estimates highlight the presence of substantial preference heterogeneity among the population, which can be partially explained by citizens socio-demographics. We also use model outputs to simulate market shares for heating systems under alternative policy scenarios. Results provide interesting suggestions to inform the design of poli-cies aimed at fostering the adoption of biomass-based heating systems
Influence of sharp stiffness variations in damage evaluation using POD and GSM
No full textDamage detection methods based on modal analysis have been widely studied in recent years.
However the calculation of mode shapes in real structures can be time consuming and often requires
dedicated software programmes. In the present paper the combined application of proper orthogonal
decomposition and gapped smoothing method to structural damage detection is presented. The first is used
to calculate the dynamic shapes of a damaged structural element using only the time response of the system
while the second is used to derive a reference baseline to which compare the data coming from the damaged
structure. Experimental verification is provided for a beam case while numerical analyses are conducted on
plates. The introduction of a stiffener on a plate is investigated and a method to distinguish its influence from
that of a defect is presented. Results highlight that the derivatives of the proper orthogonal modes are more
effective damage indices than the modes themselves and that they can be used in damage detection when
only data from the damaged structure are available. Furthermore the stiffened plate case shows how the
simple use of the curvature is not sufficient when analysing complex components. The combined application
of the two techniques provides a possible improvement in damage detection of typical aeronautical
structures
La struttura dell’eterogeneità inosservabile delle preferenze al consumo: un approccio basato sulle classi latenti da responsi discreti
No full textAmongst the determinants of the growing segmentation of demand for agrofood products, consumers’ concern for environmental issues increases the relevance of attributes such as environment-friendly production modes and food-safety issues in food choice. Capturing differences in latent preference intensities from qualitative choices in a way that allows for endogenous taste-segmentation requires the development of specific techniques which maintain consistency with the precepts of rational economic choice and utility maximization. Using a random utility latent segmentation approach we derive latent segments for carrots produced in a region (Val di Gresta, Trento) where producers have gained over time a sizeable reputation. Segments are derived on the basis of attributes such as the certified use of low-environmental impact production techniques (organic, integrated pest management and bio-dynamic) and collective brand recognition. The results indicate the presence of four distinctive groups of consumers preferences who display relevant differences in both willingness to pay and determinants of choice
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