Design, modeling and analysis of object localization through acoustical signals for cognitive electronic travel aid for blind people

El objetivo de la tesis consiste en el estudio y análisis de la localización de objetos en el entorno real mediante sonidos, así como la posterior integración y ensayo de un dispositivo real basado en tal técnica y destinado a personas con discapacidad visual. Con el propósito de poder comprender y analizar la localización de objetos se ha realizado un profundo estado de arte sobre los Sistemas de Navegación desarrollados durante las últimas décadas y orientados a personas con distintos grados de discapacidad visual. En el citado estado del arte, se han analizado y estructurado los dispositivos de navegación existentes, clasificándolos de acuerdo con los componentes de adquisición de datos del entorno utilizados. A este respecto, hay que señalar que, hasta el momento, se conocen tres clases de dispositivos de navegación: 'detectores de obstáculos', que se basan en dispositivos de ultrasonidos y sensores instalados en los dispositivos electrónicos de navegación con el objetivo de detectar los objetos que aparecen en el área de trabajo del sistema; 'sensores del entorno' - que tienen como objetivo la detección del objeto y del usuario. Esta clase de dispositivos se instalan en las estaciones de autobús, metro, tren, pasos de peatones etc., de forma que cuando el sensor del usuario penetra en el área de alcance de los sensores instalados en la estación, éstos informan al usuario sobre la presencia de la misma. Asimismo, el sensor del usuario detecta también los medios de transporte que tienen instalado el correspondiente dispositivo basado en láser o ultrasonidos, ofreciendo al usuario información relativa a número de autobús, ruta etc La tercera clase de sistemas electrónicos de navegación son los 'dispositivos de navegación'. Estos elementos se basan en dispositivos GPS, indicando al usuario tanto su locación, como la ruta que debe seguir para llegar a su punto de destino. Tras la primera etapa de elaboración del estaDunai ., L. (2010). Design, modeling and analysis of object localization through acoustical signals for cognitive electronic travel aid for blind people [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8441Palanci

Frequency dependence of the interaural time difference thresholds in human listeners

[EN] Interaural time difference (ITD) thresholds for sine tones were measured as a function of frequency with unprecedented resolution along the frequency axis. The tone level was 70 dB SPL, and the method was a two¿interval forced¿choice, three¿down one¿up staircase. Overall, the lowest thresholds occurred near 1000 Hz. At lower frequencies, thresholds varied more rapidly than the expected 1/f law, suggesting a growing deficit in elemental ITD processors as characteristic frequency decreases. At higher frequencies, thresholds increased dramatically with increasing frequency. Measurements at 50¿Hz increments were able to obtain a threshold for only one listener at 1500 Hz, but no threshold at 1550 Hz. In summary, performance varied from best to impossible over a range of about half an octave. In that sense, ITD thresholds appear to show the most dramatic frequency dependence of any auditory quantity.Dunai ., L.; Hartmann, W. (2011). Frequency dependence of the interaural time difference thresholds in human listeners. The Journal of the Acoustical Society of America. 129(4):2485-2485. doi:10.1121/1.3588183S24852485129

Improving student interest with portable laboratory tools in engineering

[EN] The desire for improving student motivation and interest in engineering learning have yielded new methodologies for active learning. The present paper presents a new methodology based on project learning and portable learning technology. The goal of the method was to improve the students’ confidence and learning in industrial design and prototyping during one semester. The results indicate that students’ motivation for learning was very high and it has been maintained during the whole semester. Also, the confidence on their learning and retention ability increased, which indicates that the method had a positive impact on the students.Dunai Dunai, L.; Antonino Daviu, JA.; Lengua Lengua, I. (2021). Improving student interest with portable laboratory tools in engineering. En Proceedings INNODOCT/20. International Conference on Innovation, Documentation and Education. Editorial Universitat Politècnica de València. 259-264. https://doi.org/10.4995/INN2020.2020.11905OCS25926

Human Hand Anatomy-Based Prosthetic Hand

[EN] The present paper describes the development of a prosthetic hand based on human hand anatomy. The hand phalanges are printed with 3D printing with Polylactic Acid material. One of the main contributions is the investigation on the prosthetic hand joins; the proposed design enables one to create personalized joins that provide the prosthetic hand a high level of movement by increasing the degrees of freedom of the fingers. Moreover, the driven wire tendons show a progressive grasping movement, being the friction of the tendons with the phalanges very low. Another important point is the use of force sensitive resistors (FSR) for simulating the hand touch pressure. These are used for the grasping stop simulating touch pressure of the fingers. Surface Electromyogram (EMG) sensors allow the user to control the prosthetic hand-grasping start. Their use may provide the prosthetic hand the possibility of the classification of the hand movements. The practical results included in the paper prove the importance of the soft joins for the object manipulation and to get adapted to the object surface. Finally, the force sensitive sensors allow the prosthesis to actuate more naturally by adding conditions and classifications to the Electromyogram sensoDunai, L.; Novak, M.; Garcia Espert, C. (2021). Human Hand Anatomy-Based Prosthetic Hand. Sensors. 21(1):1-15. https://doi.org/10.3390/s21010137S11521

Virtual Sound Localization by Blind People

[EN] The paper demonstrates that blind people localize sounds more accurately than sighted people by using monaural and/or binaural cues. In the experiment, blind people participated in two tests; the first one took place in the laboratory and the second one in the real environment under different noise conditions. A simple click sound was employed and processed with non-individual head related transfer functions. The sounds were delivered by a system with a maximum azimuth of 32◦ to the left side and 32◦ to the right side of the participant s head at a distance ranging from 0.3 m up to 5 m. The present paper describes the experimental methods and results of virtual sound localization by blind people through the use of a simple electronic travel aid based on an infrared laser pulse and the time of flight distance measurement principle. The lack of vision is often compensated by other perceptual abilities, such as the tactile or hearing ability. The results show that blind people easily perceive and localize binaural sounds and assimilate them with sounds from the environment.Dunai Dunai, L.; Lengua Lengua, I.; Peris Fajarnes, G.; Brusola Simón, F. (2015). Virtual Sound Localization by Blind People. Archives of Acoustics. 40(4):561-567. doi:10.1515/aoa-2015-0055S56156740

Material sound source localization through headphones

[EN] In the present paper a study of sound localization is carried out, considering two different sounds emitted from different hit materials (wood and bongo) as well as a Delta sound. The motivation of this research is to study how humans localize sounds coming from different materials, with the purpose of a future implementation of the acoustic sounds with better localization features in navigation aid systems or training audio-games suited for blind people. Wood and bongo sounds are recorded after hitting two objects made of these materials. Afterwards, they are analysed and processed. On the other hand, the Delta sound (click) is generated by using the Adobe Audition software, considering a frequency of 44.1 kHz. All sounds are analysed and convolved with previously measured non-individual Head-Related Transfer Functions both for an anechoic environment and for an environment with reverberation. The First Choice method is used in this experiment. Subjects are asked to localize the source position of the sound listened through the headphones, by using a graphic user interface. The analyses of the recorded data reveal that no significant differences are obtained either when considering the nature of the sounds (wood, bongo, Delta) or their environmental context (with or without reverberation). The localization accuracies for the anechoic sounds are: wood 90.19%, bongo 92.96% and Delta sound 89.59%, whereas for the sounds with reverberation the results are: wood 90.59%, bongo 92.63% and Delta sound 90.91%. According to these data, we can conclude that even when considering the reverberation effect, the localization accuracy does not sig- nificantly increase. © Pleiades Publishing, Ltd., 2012.This research was supported by Research Center in Graphic Technology from the Universidad Politecnica de Valencia.Dunai, L.; Peris Fajarnes, G.; Lengua, I.; Tortajada Montañana, I. (2012). Material sound source localization through headphones. Acoustical Physics. 58(5):610-617. doi:10.1134/S1063771012050077S610617585D. S. Brungart and W. M. Rabinowitz, J. Acoust. Soc. Am. 106, 1465 (1999).D. S. Brungart, I. Nathaniel, and W. R. Rabinowitz, J. Acoust. Soc. Am. 106, 1956 (1999).H. Bruce and D. Hirsh, J. Acoust. Soc. Am. 31, 486 (1959).D. I. Shore, S. E. Hall, and R. M. Klein, J. Acoust. Soc. Am. 103, 3730 (1998).J. C. Kidd and J. H. Hogloben, J. Acoust. Soc. Am., 116, 1116 (2004).L. Dunai, G. P. Fajarnes, B. D. Garcia, N. O. Araque, and F. B. Simon, Acoust. Phys. 55, 448 (2009).L. Dunai, G. P. Fajarnes, B. D. Garcia, and V. S. Praderas, Acoust. Phys. 56, 348 (2010).M. Gröhn, Proc. Int. Conf. on Auditory Display, Kyoto, 2002.E. S. Malinina and I. G. Andreeva, Acoust. Phys. 56, 576 (2010).E. D. Shabalina, N. V. Shirgina, and A. V. Shanin, Acoust. Phys. 56, 525 (2010).A. Pompey, M. A. Sumbatyan, and N. F. Todorov, Acoust. Phys. 55, 760 (2009).R. L. Klatzky, D. K. Pai, and E. P. Krotkov, Presence: Teleoperators and Virtual Environments 9, 399 (2000).M. Aramaki, M. Besson, R. Kronland-Martinet, and S. Ystad, Proc. 5th Int. Symp. on Comp. Music Model. Retriev. (CMMR 2008), Copenhagen, 2008, pp. 1–8.W. Gaver, PhD Dissertation, Univ. California, San Diego, 1988.N. I. Durlach, A. Rigapolus, X. D. Pang, W. S. Woods, A. Kulkarni, H. S. Colburn, and E. M. Wenzel, Presence: Teleoperators and Virtual Environments 1, 251 (1992).S. A. Gelfand, Essentials of Audiology, 3rd ed. (Thieme Medical Publishers, New York, 2009).J. Jerger, ASHA 4, 139 (1962).H. Mershon, W. L. Ballenger, A. D. Little, P. L. McMurtry, and J. L. Buchanan, Perception 18, 403 (1989).D. O. Kim, A. Moiseff, T. J. Bradley, and J. Gull, Acta Otolaryngologica 128, 328 (2008).P. Zahorik, Proc. Int. Conf. on Auditory Display, Kyoto, 2002

Detection of Field Winding Faults in Synchronous Motors via Analysis of Transient Stray Fluxes and Currents

(c) 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] The detection of rotor failures in synchronous motors is a matter of primordial interest in many industrial sites where these machines are critical assets. However, due to the particular operation of these motors, most conventional techniques relying on steady-state analysis, commonly used in other electric machines, are not applicable to such motors. In this context, it has been recently proven that the analysis of different quantities under transient operation of the motor and, more specifically, under motor starting can provide crucial information for the diagnosis of many faults. This work proposes the time-frequency analysis of stray fluxes and currents to detect field winding faults in synchronous motors. The potential consequences of this fault can be catastrophic for the motor integrity, so that the detection of its presence in its early stages can be of critical importance for the industry. The results included in this paper prove the usefulness of the transient analysis of such non-invasive quantities not only to detect the presence of the field winding fault but also to set a starting point to determine its severity.This work was supported by the Spanish Ministerio de Ciencia Innovación y Universidades and FEDER program in the framework of the Proyectos de I+D de Generación de Conocimiento del Programa Estatal de Generación de Conocimiento y Fortalecimiento Científico y Tecnológico del Sistema de I+D+i, Subprograma Estatal de Generación de Conocimiento (ref: PGC2018-095747-B-I00).Tian, P.; Antonino Daviu, JA.; Platero, C.; Dunai, L. (2021). Detection of Field Winding Faults in Synchronous Motors via Analysis of Transient Stray Fluxes and Currents. IEEE Transactions on Energy Conversion. 36(3):2330-2338. https://doi.org/10.1109/TEC.2020.3041643S2330233836

Euro Banknote Recognition System for Blind People

[EN] This paper presents the development of a portable system with the aim of allowing blind people to detect and recognize Euro banknotes. The developed device is based on a Raspberry Pi electronic instrument and a Raspberry Pi camera, Pi NoIR (No Infrared filter) dotted with additional infrared light, which is embedded into a pair of sunglasses that permit blind and visually impaired people to independently handle Euro banknotes, especially when receiving their cash back when shopping. The banknote detection is based on the modified Viola and Jones algorithms, while the banknote value recognition relies on the Speed Up Robust Features (SURF) technique. The accuracies of banknote detection and banknote value recognition are 84% and 97.5%, respectively.The work was supported by the project from the Generalitat Valenciana under the number GV/2014/015-Emergency projects.Dunai, L.; Chillarón-Pérez, M.; Peris Fajarnes, G.; Lengua, I. (2017). Euro Banknote Recognition System for Blind People. Sensors. 17(1)(184):1-14. https://doi.org/10.3390/s17010184S11417(1)18

THREE DIMENSIONAL ENVIRONMENT LOCALIZATION THROUGH VIRTUAL SOUND EXPERIMENTAL

[EN] The paper deal with the development of an experimental for 32 virtual simultaneous sound localization. The experimental is based on the development of two interfaces: the graphic virtual environment that includes different images as plane geometric figures and three dimensional geometric figures and daily figures as trees, etc. and the virtual acoustic sounds. The experimental treats to study simultaneous sound sources localization through headphones, as the study of the psychoacoustic characteristics on simultaneous sound localization. For the experimental was analysed the time dependence and intensity and frequency dependence as time thresholds. The virtual sounds are generated in real time in elevation, direction and depth. Previous results demonstrate that the humans are able to perceive simultaneous sounds and to localize them in the environment.Dunai, L.; Prieto-López, AE.; Lengua, I.; Defez Garcia, B. (2016). THREE DIMENSIONAL ENVIRONMENT LOCALIZATION THROUGH VIRTUAL SOUND EXPERIMENTAL. Universidade do Porto. 1-5. http://hdl.handle.net/10251/181070S1

Design and development of an acoustic object detector device for blind people

[EN] The main design and development characteristics of an acoustic object device for blind people are presented. The study focuses on the presentation of the main steps of device design, the motivation why this product is important and the development of the first prototype. The results from the device evaluation yield to demonstrate than electronic elements using for vehicles can be used for small object detector devices for blind people and incorporated into a small sunglass. Good design helps engineers to develop the product in an easy way.The work remarks the main characteristics for a good device design and intends to inspire designers to become involved in the use of integrated technologies to promote independent lives for visually disabled people and promote an esthetically adequate design.[ES] Se describen las características más significativas del diseño y desarrollo de un dispositivo acústico detector de obstáculos para las personas con discapacidad visual. El estudio está enfocado en la descripción de las etapas de diseño, la motivación de porqué es importante el diseño, y el desarrollo del primer prototipo. Los resultados obtenidos del dispositivo tienden a demonstrar que la tecnología utilizada para la detección de obstáculos para los vehículos puede ser utilizada en pequeños dispositivos para personas con discapacidad visual. Un buen diseño les permite a los ingenieros desarrollar los productos de forma más sencilla. El trabajo remarca las principales características de un buen diseño industrial y pretende inspirar a los diseñadores para involucrarse en la integración de tecnologías para mejorar la vida de las personas con discapacidad visual teniendo en cuenta el aspecto estético.Los autores agradecen a la Generalitat Valenciana (proyecto GV/2014/015 - proyectos emergentes) y a la Comisión Europea (Grant FP6 Programme).Dunai Dunai, L.; Lengua Lengua, I.; Brusola Simón, F.; Peris Fajarnes, G. (2015). Diseño y desarrollo de un dispositivo acústico detector de obstáculos para personas con discapacidad visual. Interciencia: journal of science and technology of the Americas. 40(12):854-858. http://hdl.handle.net/10251/63550S854858401