Spell-checking in Spanish: the case of diacritic accents

This article presents the problem of diacritic restoration (or diacritization) in the context of spell-checking, with the focus on an orthographically rich language such as Spanish. We argue that despite the large volume of work published on the topic of diacritization, currently available spell-checking tools have still not found a proper solution to the problem in those cases where both forms of a word are listed in the checker’s dictionary. This is the case, for instance, when a word form exists with and without diacritics, such as continuo ‘continuous’ and continuó ‘he/she/it continued’, or when different diacritics make other word distinctions, as in continúo ‘I continue’. We propose a very simple solution based on a word bigram model derived from correctly typed Spanish texts and evaluate the ability of this model to restore diacritics in artificial as well as real errors. The case of diacritics is only meant to be an example of the possible applications for this idea, yet we believe that the same method could be applied to other kinds of orthographic or even grammatical errors. Moreover, given that no explicit linguistic knowledge is required, the proposed model can be used with other languages provided that a large normative corpus is available.Peer ReviewedPostprint (author’s final draft

Analysis of the performance of a passive hybrid powerplant to power a lightweight unmanned aerial vehicle for a high altitude mission

The objective of this research is to analyze the performance of a passive hybrid powerplant control system to be implemented in a lightweight unmanned aerial vehicle capable to ascend up to the high troposphere (10, 000 m). The powerplant is based on a high-temperature PEM fuel cell connected in parallel to a set of lithium-polymer batteries and regulated by two power diodes. Test performed in steady state demonstrates that the use of the hybrid system increases the efficiency of the stack by more than 7% because the voltage at the main DC bus is limited by the batteries. The robustness of the passive control system is proved in a long-term test in which random perturbations of ±15% are applied to the average power that would be demanded during the ascent flight. The hybridization of the stack with the batteries eliminates sudden peaks in the current generated by the stack, which are responsible for prompt degradation phenomena that drastically reduce its useful lifetime. The study demonstrates that with the passive hybrid powerplant it is possible to reach the target height with the gas storage system considered in the application, contrary to what happens with the simple power plant

Experimental determination of the heat transfer coefficient for the optimal design of the cooling system of a PEM fuel cell placed inside the fuselage of an UAV

The objective of this research is to calculate the heat transfer coefficients needed for the further design of the optimal cooling system of a high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC) stack that will be incorporated to the powerplant of a light unmanned aerial vehicle (UAV) capable of reaching an altitude of 10,000 m. Experiments are performed in two rectangular tunnels, for three different form factors, in experimental conditions as close as possible to the actual ones in the HT-PEMFC stack. For the calculations, all the relevant thermal processes are considered (i.e., convection and radiation). Different parameters are measured, such as air mass flow rate, inlet and outlet air temperatures, and wall temperatures for bipolar plates and endplates. Different numerical models are fitted revealing the influence of the diverse relevant non-dimensional groups on the Nusselt number. Heat transfer coefficients calculated for the air cooling flow vary from 8 to 44 W m2 K1. Results obtained at sea level are extrapolated for a flight ceiling of 10 km. The flow section is optimized as a function of the power required to cool the stack down to the temperature recommended by the membrane-electrode assembly (MEA) manufacturer using a numerical code specifically developed for this purpose

Assessment of a Wind Turbine Blade Erosion Lifetime Prediction Model with Industrial Protection Materials and Testing Methods

Leading edge protection (LEP) coating systems are applied to protect turbine blade edges from rain erosion. The performance of a LEP system is assessed in an accelerated rain erosion test (RET) as a metric for industrial application, but these tests are expensive. Modelling methods are available to predict erosion, based on fundamental material properties, but there is a lack of validation. The Springer model (1976) is analysed in this work to assess it as a tool for using material fundamental properties to predict the time to failure in a rain erosion test. It has been applied, referenced and industry validated with important partial considerations. The method has been applied successfully for erosion damage by wear performance prediction when combined with prior material data from rain erosion test (RET), instead of obtaining it directly from fundamental properties measured separately as Springer proposed. The method also offers accurate predictions when coupled with modified numerical parameters obtained from experimental RET testing data. This research aims to understand the differences between the experimental data used by Springer and the current industry approach to rain erosion testing, and to determine how it may introduce inaccuracies into lifetime predictions of current LEP systems, since they are very different to those tested in the historic modelling validation. In this work, a review of the modelling is presented, allowing for the understanding of key issues of its computational implementation and the required experimental material characterisation. Modelling results are discussed for different original application issues and industry-related LEP configuration cases, offering the reader to interpret the limits of the performance prediction when considering the variation in material fundamental properties involved

Use of fuel cell stacks to achieve high altitudes in light unmanned aerial vehicles

A study is presented to determine if substituting an internal combustion engine (ICE) by an electric motor powered by a fuel cell stack can be a viable option to increase the service ceiling of an available light unmanned aerial vehicle (UAV), extending it to 10,000 m. As a first condition, the stack has to be capable of supplying the minimum power required for horizontal leveled flight at this altitude, which is a function of the UAV total mass. A second step examines if the UAV can transport the energy required to reach the desired service ceiling without exceeding the maximum mass that can be loaded, considering that both hydrogen and oxygen have to be carried on-board. A particularly light PEM fuel cell stack is proposed as a suitable power source. A realistic system is described to store the required amount of reactant gases maintaining the mass below the allowable limits. Results indicate that with its aerodynamic characteristics, the UAV should be capable of ascending up to 10,000 m with the described fuel cell and gas storage system. Some multivariable maps that include service ceiling, total payload and required power are provided to perform this type of analysis

Spell-checking in Spanish: the case of diacritic accents

This article presents the problem of diacritic restoration (or diacritization) in the context of spell-checking, with the focus on an orthographically rich language such as Spanish. We argue that despite the large volume of work published on the topic of diacritization, currently available spell-checking tools have still not found a proper solution to the problem in those cases where both forms of a word are listed in the checker’s dictionary. This is the case, for instance, when a word form exists with and without diacritics, such as continuo ‘continuous’ and continuó ‘he/she/it continued’, or when different diacritics make other word distinctions, as in continúo ‘I continue’. We propose a very simple solution based on a word bigram model derived from correctly typed Spanish texts and evaluate the ability of this model to restore diacritics in artificial as well as real errors. The case of diacritics is only meant to be an example of the possible applications for this idea, yet we believe that the same method could be applied to other kinds of orthographic or even grammatical errors. Moreover, given that no explicit linguistic knowledge is required, the proposed model can be used with other languages provided that a large normative corpus is available.Peer Reviewe

Spell-checking in Spanish: the case of diacritic accents

This article presents the problem of diacritic restoration (or diacritization) in the context of spell-checking, with the focus on an orthographically rich language such as Spanish. We argue that despite the large volume of work published on the topic of diacritization, currently available spell-checking tools have still not found a proper solution to the problem in those cases where both forms of a word are listed in the checker’s dictionary. This is the case, for instance, when a word form exists with and without diacritics, such as continuo ‘continuous’ and continuó ‘he/she/it continued’, or when different diacritics make other word distinctions, as in continúo ‘I continue’. We propose a very simple solution based on a word bigram model derived from correctly typed Spanish texts and evaluate the ability of this model to restore diacritics in artificial as well as real errors. The case of diacritics is only meant to be an example of the possible applications for this idea, yet we believe that the same method could be applied to other kinds of orthographic or even grammatical errors. Moreover, given that no explicit linguistic knowledge is required, the proposed model can be used with other languages provided that a large normative corpus is available.Peer Reviewe

Translation and validation of the Ten-Item-Personality Inventory into spanish and catalan

In response to an increasing need for ever-shorter personality instruments, Gosling, Rentfrow, and Swann (2003) developed the Ten-Item-Personality Inventory (TIPI), which measures the dimensions of the Five Factor Model (FFM) using 10 items (two for each dimension) and can be administered in about one minute. In two studies and using a multi-judge (self and observer) and multi-instrument design, we develop Spanish (Castilian) and Catalan versions of the TIPI and evaluate them in terms of internal consistency, test-retest reliability, convergent, discriminant, and content validity, as well as self-observer correlations. Test-retest correlations were strong, and convergence with the NEO-PI-R factors was significant. There were also strong correlations between observer ratings and the participants’ self-ratings. Despite some inconsistencies with respect to the Agreeableness scale, the Catalan translation and both translations into Spanish of the original TIPI demonstrated sufficient psychometric properties to warrant use as a Five Factor personality measure when the use of longer instruments is not convenient or possible. Furthermore, as the first translation of a brief standard Big Five Instrument into Catalan, this work should facilitate future research on personality in the Catalan-speaking population

Estudi de Paisatge : El Clot

Sol·licitant de l'informe: Institut Municipal del Paisatge Urbà i la Qualitat de Vida (Barcelona