Hypothesis Testing in Functional Comparative Calibration Models

The purpose of this article is to investigate hypothesis testing in functional comparative calibration models. Wald type statistics are considered which are asymptotically distributed according to the chi-square distribution. The statistics are based on maximum likelihood, corrected score approach, and method of moment estimators of the model parameters, which are shown to be consistent and asymptotically normally distributed. Results of analytical and simulation studies seem to indicate that the Wald statistics based on the method of moment estimators and the corrected score estimators are, as expected, less efficient than the Wald type statistic based on the maximum likelihood estimators for small n. Wald statistic based on moment estimators are simpler to compute than the other Wald statistics tests and their performance improves significantly as n increases. Comparisons with an alternative F statistics proposed in the literature are also reported.     

Fuzzy Autoregressive Rules: Towards Linguistic Time Series Modeling

Fuzzy rule–based models, a key element in soft computing (SC), have arisen as an alternative for time series analysis and modeling. One difference with preexisting models is their interpretability in terms of human language. Their interactions with other components have also contributed to a huge development in their identification and estimation procedures. In this article, we present fuzzy rule–based models, their links with some regime-switching autoregressive models, and how the use of soft computing concepts can help the practitioner to solve and gain a deeper insight into a given problem. An example on a realized volatility series is presented to show the forecasting abilities of a fuzzy rule–based model.     

On limiting behavior for arrays of rowwise negatively orthant dependent random variables

In this paper, the authors study limiting behavior for arrays of rowwise negatively orthant dependent random variables and obtain some new results which extend and improve the corresponding theorems by Hu, Móricz, and Taylor (1989), Taylor, Patterson, and Bozorgnia (2002) and Wu and Zhu (2010).     

Reliability of translated measures assessing dating violence among Mexican adolescents

Research on the prevalence and correlates of dating violence in Mexican teens is challenged by the lack of culturally and linguistically appropriate assessment tools. This study modified, translated, and back-translated the Conflict in Adolescent Dating Relationships Inventory (CADRI; Wolfe et al., 2001) and the Attitudes Towards Dating Violence Scales (Price, Byers, & the Dating Violence Research Team, 1999) for Mexican adolescents. Analyses on 307 adolescents (15-18 years old) from Monterrey and Mexicali, Mexico, revealed that most of the translated CADRI subscales and Attitudes Towards Dating Violence Scales had acceptable internal consistency and test-retest reliability coefficients. The study offers some evidence that the measures may be useful in assessing dating violence in Mexican teens.     

Effective strategies for socio-educational intervention during the process of transition to adult life of unaccompanied minors from Africa

The arrival of unaccompanied minors from Africa in Spanish territory has been a constant since the last decade of the twentieth century. This migratory phenomenon has forced the child welfare system to attend to thousands of migrant children. The transition to adult life is a decisive stage in overcoming the situation of social exclusion. This research aims to analyse which socio-educational intervention strategies are effective during the process of transition to independent living with unaccompanied minors of African origin. We designed a qualitative research according to the grounded theory, which we divided into two phases. Twenty-nine young people (26 men and 3 women) participated. In phase 1, we performed two focus groups (N = 11), and in phase 2, we conducted longitudinal follow-ups (N = 18) for 24 months through 180 interviews. The results indicate the effectiveness of designing socio-educational accompaniment, prioritizing spaces of trust from which to attain the goals of emancipation. Young people consider effective those strategies that favour their knowledge of the social, labour and legal reality of the host society, designed considering each minor's individualized situation. We concluded that professional involvement acts as a buffer, reducing the bureaucratic obstacles implemented by the Spanish government.     

A TECHNIQUE TO MINIMIZE OVERTIME IN THE CAPACITATED MRP PROBLEM

Since the development of early versions of material requirements planning (mrp) systems, it has been known that a weak link in this technique is the failure to consider the available capacity at the time the lot sizes for individual items are calculated. Ignoring the available capacity may result in infeasible production plans, i.e., those that can only be accomplished with the use of overtime. We present a technique to search for feasible production plans by means of minimizing the total overtime. The technique is based on modifying periodic-order-quantity (poq) lot sizes within a tabu search framework. Computational experiments with the largest problem structure reported in the literature show that the procedure is effective in determining lot sizes for individual items that either minimize or eliminate overtime. Additional experiments reveal that, with appropriate calibration of search parameters, the procedure is also able to deal with more general cost functions (e.g., those that include holding and setup costs).     

Locking down adolescents: Victims,irresponsible subjects,or just social actors

The article presents the results of a qualitative study investigating the experiences of a sample of Italian adolescents during the COVID-19 pandemic. Data were analysed in the light of the two social representations (adolescents as criminals and as victims) that permeated the Italian public debate throughout the outbreak. The findings showed the ability of boys and girls in dealing with the relationships altered by the pandemic constraints and in adapting to different regulations. This demonstrated their competence as social actors, neither criminals nor victims, who were also able to cope with the coronavirus risk in safeguarding their significant others.     

Accuracy of Numerical Solutions Using the Euler Equation Residuals

This paper is concerned with asymptotic properties on the accuracy of numerical solutions. It is shown that the approximation error of the policy function is of the same order of magnitude as the size of the Euler equation residuals. Moreover, for bounding this approximation error the most relevant parameters are the discount factor and the curvature of the return function. These findings provide theoretical foundations for the construction of tests to assess the performance of alternative computational methods.