Fernando López-Colino

Ontology-Based Retrieval of Human Speech

As part of the general growth and diversification of media in different modalities, the presence of information in the form of human speech in the world-wide body of digital content is becoming increasingly significant, in terms of both volume and value. We present a semantic- based search model for human speech corpora, stressing the search for meanings rather than words. Our framework embraces the complete recognition/retrieval cycle, from word spotting to semantic annotation, query processing, and search result presentation.

Simplified occupancy grid indoor mapping optimized for Low-Cost robots

This paper presents a mapping system that is suitable for small mobile robots. An ad hoc algorithm for mapping based on the Occupancy Grid method has been developed. The algorithm includes some simplifications in order to be used with low-cost hardware resources. The proposed mapping system has been built in order to be completely autonomous and unassisted. The proposal has been tested with a mobile robot that uses infrared sensors to measure distances to obstacles and uses an ultrasonic beacon system for localization, besides wheel encoders. Finally, experimental results are presented.

A rule-based translation from written Spanish to Spanish Sign Language glosses

HighlightsRule-based approach for a Spanish-to-LSE machine translation system for wide-domain application.The proposed approach is based on the transfer at the level of syntatic functions from dependency analysis and employs three different stages: analysis, transfer and generation.Morpho-lexical and lexical-semantic relationships are used in to expand the bilingual Spanish-LSE lexicon aiming at reducing the lexical gap between Spanish and LSE.The rule-based approach also integrates classifier predicate generation.Results present a 0.30 BLEU and 42% TER. Includes experiments and comparison with data-driven approaches, experiments with surface order, and linguistic-oriented error analysis. One of the aims of Assistive Technologies is to help people with disabilities to communicate with others and to provide means of access to information. As an aid to Deaf people, we present in this work a production-quality rule-based machine system for translating from Spanish to Spanish Sign Language (LSE) glosses, which is a necessary precursor to building a full machine translation system that eventually produces animation output. The system implements a transfer-based architecture from the syntactic functions of dependency analyses. A sketch of LSE is also presented. Several topics regarding translation to sign languages are addressed: the lexical gap, the bootstrapping of a bilingual lexicon, the generation of word order for topic-oriented languages, and the treatment of classifier predicates and classifier names. The system has been evaluated with an open-domain testbed, reporting a 0.30 BLEU (BiLingual Evaluation Understudy) and 42% TER (Translation Error Rate). These results show consistent improvements over a statistical machine translation baseline, and some improvements over the same system preserving the word order in the source sentence. Finally, the linguistic analysis of errors has identified some differences due to a certain degree of structural variation in LSE.

Spanish Sign Language synthesis system

This work presents a new approach to the synthesis of Spanish Sign Language (LSE). Its main contributions are the use of a centralized relational database for storing sign descriptions, the proposal of a new input notation and a new avatar design, the skeleton structure of which improves the synthesis process. The relational database facilitates a highly detailed phonologic description of the signs that include parameter synchronization and timing. The centralized database approach has been introduced to allow the representation of each sign to be validated by the LSE National Institution, FCNSE. The input notation, designated HLSML, presents multiple levels of abstraction compared with current input notations. Redesigned input notation is used to simplify the description and the manual definition of LSE messages. Synthetic messages obtained using our approach have been evaluated by deaf users; in this evaluation a maximum recognition rate of 98.5% was obtained for isolated signs and a recognition rate of 95% was achieved for signed sentences.

Hybrid paradigm for Spanish Sign Language synthesis

This work presents a hybrid approach to sign language synthesis. This approach allows the hand-tuning of the phonetic description of the signs, which focuses on the time aspect of the sign. Therefore, the approach retains the capacity for the performing of morpho-phonological operations, like notation-based approaches, and improves the synthetic signing performance, such as the hand-tuned animations approach. The proposed approach simplifies the input message description using a new high-level notation and storage of sign phonetic descriptions in a relational database. Such relational database allows for more flexible sign phonetic descriptions; it also allows for a description of sign timing and the synchronization between sign phonemes. The new notation, named HLSML, is a gloss-based notation focusing on message description in it. HLSML introduces several tags that allow for the modification of the signs in the message that defines dialect and mood variations, both of which are defined in the relational database, and message timing, including transition durations and pauses. A new avatar design is also proposed that simplifies the development of the synthesizer and avoids any interference with the independence of the sign language phonemes during animation. The obtained results showed an increase of the sign recognition rate compared to other approaches. This improvement was based on the active role that the sign language experts had in the description of signs, which was the result of the flexibility of the sign storage approach. The approach will simplify the description of synthesizable signed messages, thus facilitating the creation of multimedia-signed contents.

Handling input voltage frequency variations in power factor correctors with precalculated duty cycles

The use of precalculated duty cycles for power factor correction leads to a significant simplification of the design and a reduction of the final cost. There are previous proposals for handling non-nominal conditions such as input voltage or load variations. However, there are no proposals for handling input frequency variations, which have an important impact in the power factor. This paper measures this impact and includes a simple loop to handle the variations of the input frequency. The results show that the introduction of this loop keeps the power factor values around those obtained in nominal conditions.

Comparison of AC mains synchronization methods when using precalculated duty cycles in Power Factor Correction

Classic PFC (Power Factor Correction) converters usually have three sensors: input voltage, input current and output voltage. Instead of using these three measures to calculate the duty cycle, precalculated duty cycles can be stored in a memory. With this memory, the system only has to synchronize with the ac mains and apply the duty cycles, at least for nominal conditions. This paper shows several methods to accomplish this synchronization, using an ADC or a voltage comparator. Results show that PFC can be achieved using simple synchronization methods and precalculated duty cycles.

Modeling of power converters for debugging digital controllers through FPGA emulation

Debugging a digital controller for power converters can be a lengthy process due to the long time required in mixed-signal simulations. This paper focuses on the design of a power converter model for debugging digital controllers in closed loop. The testing may be performed by means of simulation or emulation. This paper shows the results of simulating and emulating the power converter using different data representations. Experiments will show that through a good selection of data and emulation, testing can be speeded up over 28,000 times.

Full Skeleton-based Virtual Human Animation: An Improved Design for SL Avatars

ABSTRACT This paper presents a novel skeleton design for avatar animation. This design includes new bones, whose purpose is to meet the requirements of sign language (SL) synthesis. SL synthesis presents particular challenges regarding the processing of phonetic descriptions of signs to create animations. Although traditional animation techniques have solved the synthesis of signs, the proposed skeleton design allows for the simplification of the phonetic processing, the inverse kinematics calculations, and the collision avoidance processes. The proposed design has been tested to demonstrate that the generated animations have the same quality as the ones produced with state-of-the-art techniques. Importantly, the proposed structure reduces the time required for generating an animation by 52% compared to existing solutions and requires less storage resources.

Development of an online platform for hardware-based laboratories in Engineering studies

This work presents the development of a remote laboratory service and its application during the teaching of Control Systems subject of third course in a Telecommunication Technology and Service Engineering degree. The application was successful allowing the student to control the same components as remotely, in a similar way as they were in the laboratory. There was an elevated interest by the students, who highlighted the useful of the tool. Furthermore, this proposal solved the hardware assembly difficulties improving the qualifications in a 40% in the particular aspects in which this project could be applied.