We address in this paper the question of how to verify program properties in modern functional logic languages, where it is allowed the presence of non-deterministic functions with call-time choice semantics. The main problem to face is that for such kind of programs equational reasoning is not valid. We develop some logical conceptual tools providing sound reasoning mechanisms for these programs, in particular for proving properties valid in the initial model of a program. We show how CRWL, a well known logical framework for functional logic programming, can be easily mapped into logic programming, and we use this mapping as a starting point of our work. We explore then how to prove properties of the resulting logic programming translation by means of different existing interactive proof assistants, and afterwards we give some proposals trying to overcome the limitations of the approach, specially with respect to its theoretical strength.

The purpose of this study is to determine if there is any correlation between the characteristics of the user’s eye movements (EMs) and the preference of the user when wearing different Progressive power lenses (PPLs) distributions. An eye-tracker system with a sample rate of 120Hz and temporal resolution of 8.3ms (Tobii-X3-120) was used to register EMs of 38 PPL users when reading in a computer screen with 2 types of PPLs (PPL-soft and PPL-hard). Number of fixations, complete fixation time, fixation duration mean, saccade duration mean, saccade distance mean, and number of regressions were analyzed for 6 different regions of the computer screen. A statistically significant difference was observed between the characteristics of the user’s EMs and the user’s PPL subjective preference (p<0.05*). Subjects that preferred the PPL-hard presented significantly lower complete fixation time, lower fixation duration mean and lower number of regressions than those subjects indicating a preference for the PPL-soft. Results of this study suggest that eye-tracking systems can be used as PPL design recommendation systems according to the user EMs performance.

In this paper we present an automatic evaluation tool for fuzzy first order logic formulas. Since different semantics can be considered for every logical symbol, we allow for such formulas the appearance of syntactic modifiers, in such away that our tool is designed not only to evaluate formulas in existing fuzzy semantics, but also to evaluate the properties in any other semantic framework given by the user. Such generalization is performed using Haskell functional programming language.

Early detection and treatment of refractive defects during school age are essential to avoid irreversible future vision loss and potential school problems. Previously, vision screening of preschool children used methods based on subjective visual acuity; however, technologies such as photorefraction have promoted the detection of refractive errors quickly and easily. In this study, 1347 children from 10 schools in Madrid aged 4 to 12 years participated in a program of early detection of visual problems, which consisted of visual screening composed of anamnesis and photorefraction with a PlusOptix A12R. The prevalence of refractive errors was analyzed in terms of spherical equivalent, cylinder and its orientation, and potential cases of development of high myopia or amblyopia. Hyperopia predominates in the early years, but the number of myopic subjects is higher than that of hyperopic subjects from the age of ten onwards. At all ages, the predominant orientation of astigmatism was with-the-rule. On average, 80% of the myopic subjects were uncorrected. Potential high myopia increased with age, from 4 to 21% of the measured population. Potential amblyopia cases decreased across age groups, from 19 to 13.7%. There is a need to raise awareness of the importance of vision screening at school age to address vision problems.

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