DEIO-Artículos
URI permanente para esta colecciónhttps://hdl.handle.net/10953/197
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Examinando DEIO-Artículos por Autor "Conde-Sánchez, Antonio"
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Ítem A new approach to truncated regression for count data(Springer, 2018-12-10) Martínez-Rodríguez, Ana M.; Conde-Sánchez, Antonio; Olmo-Jiménez, María J.Standard Poisson and negative binomial truncated regression models for count data include the regressors in the mean of the non-truncated distribution. In this paper, a new approach is proposed so that the explanatory variables determine directly the truncated mean. The main advantage is that the regression coefficients in the new models have a straightforward interpretation as the effect of a change in a covariate on the mean of the response variable. A simulation study has been carried out in order to analyze the performance of the proposed truncated regression models versus the standard ones showing that coefficient estimates are now more accurate in the sense that the standard errors are always lower. Also, the simulation study indicates that the estimates obtained with the standard models are biased. An application to real data illustrates the utility of the introduced truncated models in a hurdle model. Although in the example there are slight differences in the results between the two approaches, the proposed one provides a clear interpretation of the coefficient estimates.Ítem Applying the personal and social responsibility model-based program: Differences according to gender between basic psychological needs, motivation, life satisfaction and intention to be physically active(MDPI, 2019-07-01) Manzano-Sánchez, David; Valero-Valenzuela, Alfonso; Conde-Sánchez, Antonio; Chen, Ming-YaoThe objective of the study was to evaluate the impact of a program based on the Teaching Personal and Social Responsibility (TPSR) on the variables of responsibility, basic psychology needs, motivation, satisfaction with life and the intention to be physically active, as well as the differences of gender. The participants were 85 students (experimental group n = 35, 17 girls and control group n = 50, 28 girls). The students of the experimental group received the TPSR for 8 months within the physical education subject. The findings indicated an improvement in the experimental group in terms of personal responsibility and in the case of female students, in basic psychological needs and intrinsic motivation. In conclusion, the TPSR program can be integrated into the physical education curriculum in order to improve the personal responsibility of students and fulfill their motivation and satisfaction of basic psychological needs.Ítem DGLMExtPois: Advances in Dealing with Over and Under-dispersion in a Double GLM Framework(The R Foundation, 2022-12) Sáez-Castillo, Antonio J.; Conde-Sánchez, Antonio; Martínez, FranciscoIn recent years the use of regression models for under-dispersed count data, such as COM-Poisson or hyper-Poisson models, has increased. In this paper the DGLMExtPois package is presented. DGLMExtPois includes a new procedure to estimate the coefficients of a hyper-Poisson regression model within a GLM framework. The estimation process uses a gradient-based algorithm to solve a nonlinear constrained optimization problem. The package also provides an implementation of the COM-Poisson model, proposed by Huang (2017), to make it easy to compare both models. The functionality of the package is illustrated by fitting a model to a real dataset. Furthermore, an experimental comparison is made with other related packages, although none of these packages allow you to fit a hyper-Poisson model.Ítem How do sentiments affect virality on Twitter?(The Royal Society, 2021-04-14) Jiménez-Zafra, Salud M.; Sáez-Castillo, Antonio J.; Conde-Sánchez, Antonio; Martín-Valdivia, M. TeresaVirality on Twitter is catching the attention of researchers, trying to identify factors which increase or decrease the probability of retweeting. We study how terms expressing sentiments affect retweeting frequencies by means of a regression model on the number of retweets, which is specially accurate to deal with virality. We focus on the Spanish political situation during the pseudo-referendum held in Catalonia on 1 October 2017. We have found that the use of negativity in a tweet increases the probability of retweeting and that iSOL lexicon is the one that better determines the relationship between polarity and virality.Ítem Study of the synergistic impact of Fe3O4, Na2CO3 and organic C on kaolin-based lightweight aggregates by a DOE (Mixture Experiments) approach(Elsevier, 2023-11-03) Moreno-Maroto, José Manuel; Cobo-Ceacero, Carlos Javier; Martínez-Rodríguez, Ana María; Conde-Sánchez, Antonio; González-Corrochano, Beatriz; Alonso-Azcárate, Jacinto; Uceda, Manuel; López-García, Ana Belén; Martínez-García, Carmen; Cotes, TeresaThe compositional synergies involved in the thermal formation of lightweight aggregates (LWAs) have been investigated through four pure phases: non-expansive kaolin (K); cork powder (C); sodium carbonate (N) and magnetite-Fe3O4 (M). Mixture Experiments has been applied for formulation, modeling and optimization. LWAs have been manufactured from 36 starting mixtures and the main technological properties have been characterized: bloating index (BI), particle density (ρrd), water absorption (WA24) and crushing strength (S). Maximum BI and WA24 together with minimum density are associated with the addition of a significant amount of iron phase in combination with small proportions of organic carbon (Optimal [BI > 60%]: 56.0% K + 40.2% M + 3.9% C + 0% N), while S increases antagonistically with expansion. Iron reduction by incomplete combustion of C appears to be critical in pore formation and concomitant bloating. N has enhanced the sphericity of the expanded specimens. The contrast between experimental and estimated data has shown that the models have generally performed very well.