Automatic online signature verification using HMMs with user-dependent structure

Producción CientíficaA novel strategy for Automatic online Signature Verification based on hidden Markov models (HMM) with user-dependent structure is presented in this work. Under this approach, the number of states and Gaussians giving the optimal prediction results are independently selected for each user. With this simple strategy just three genuine signatures could be used for training, with an EER under 2.5% obtained for the basic set of raw signature parameters provided by the acquisition device. This results increment by a factor of six the accuracy obtained with the typical approach in which claim-independent structure is used for the HMMs.Ministerio de Educación y Formación Profesional (contract TIC2003-08382-C05-03)Junta de Castilla y Leon (project VA053A05

Memorias de los Proyectos de Innovación Docente: Año 2016-2017

Los Proyectos de Innovación Docente de la Universidad de Valladolid reflejan la mejora en la docencia universitaria. Estos proyectos nos permiten visibilizar el mapa de acciones que en la Universidad de Valladolid se están llevando a cabo (individuales o colectivas) para la mejora de la calidad docente, apostando en última instancia por mejorar el aprendizaje de los estudiantes de las diferentes titulaciones de dicha universidad

Proyectos de Innovación Docente de la Universidad de Valladolid (UVa): de los años 2013-2014 y 2014-2015

Los Proyectos de Innovación Docente de la Universidad de Valladolid reflejan la mejora en la docencia universitaria. Estos proyectos nos permiten visibilizar el mapa de acciones que en la Universidad de Valladolid se están llevando a cabo (individuales o colectivas) para la mejora de la calidad docente, apostando en última instancia por mejorar el aprendizaje de los estudiantes de las diferentes titulaciones de dicha universidad

Memorias de los Proyectos de Innovación Docente: Año 2015-2016

Los Proyectos de Innovación Docente de la Universidad de Valladolid reflejan la mejora en la docencia universitaria. Estos proyectos nos permiten visibilizar el mapa de acciones que en la Universidad de Valladolid se están llevando a cabo (individuales o colectivas) para la mejora de la calidad docente, apostando en última instancia por mejorar el aprendizaje de los estudiantes de las diferentes titulaciones de dicha universidad

Análisis del castellano guiado por una jerarquía preposicional

En las lenguas existen casos morfológicos o casos asignados por la posición y las preposiciones, que determinan la función y el papel semántico de los argumentos. Proponemos dirigir el análisis con el caso para analizar lenguas con orden (semi)libre. En castellano el orden de las palabras en el sujeto y el objeto directo inanimado y las preposiciones en el resto de los casos permitirían conducir el análisis. Las preposiciones expresan relaciones gramaticales entre los términos que unen y exigen la concordancia semántica con dichos términos. Si se conocen a priori las posibles relaciones que puede representar cada preposición y los posibles valores semánticos que puede tomar, se podrá analizar sintácticamente obteniendo la función y el papel semántico de cada sintagma en una oración, sin tener en cuenta el orden en el que aparece, basándose solamente en la preposición que rige dicho sintagma y el valor semántico de los términos que relaciona.There are either morphological cases or cases assigned by word order and prepositions which determine function and semantic role of the arguments. We propose to lead parser by prepositional case to analize semifree order languages. In Spanish, word order and agreement will identify subject and inanimate direct object whereas prepositions will do the rest. Prepositions express grammatical relations between the elements which the bind. They demand semantic agreement between them and their argument and the verb. If we previously state relations which prepositions express and semantic values that they can have, we will be able to parse by obtaining function and semantic role of arguments. This will allow us to parse without referring to word order and to restrict the combinations between verbs, prepositions and NPs semantically.Este trabajo ha sido parcialmente financiado por la Junta de Castilla y León con cargo al proyecto VA16/00

Practical on-line signature verification

Producción CientíficaA new DTW-based on-line signature verification system is presented and evaluated. The system is specially designed to operate under realistic conditions, it needs only a small number of genuine signatures to operate and it can be deployed in almost any signature capable capture device. Optimal features sets have been obtained experimentally, in order to adapt the system to environments with different levels of security. The system has been evaluated using four on-line signature databases (MCYT, SVC2004, BIOMET and MyIDEA) and its performance is among the best systems reported in the state of the art. Average EERs over these databases lay between 0.41% and 2.16% for random and skilled forgeries respectively.Junta de Castilla y León (project VA077A08

Feature selection in a low cost signature recognition system based on normalized signatures and fractional distances

Producción CientíficaIn a previous work a new proposal for an efficient on-line signature recognition system with very low computational load and storage requirements was presented. This proposal is based on the use of size normalized signatures, which allows for similarity estimation, usually based on DTW or HMMs, to be performed by an easy distance calcultaion between vectors, which is computed using fractional distance. Here, a method to select representative features from the normalized signatures is presented. Only the most stable features in the training set are used for distance estimation. This supposes a larger reduction in system requirements, while the system performance is increased. The verification task has been carried out. The results achieved are about 30% and 20% better with skilled and random forgeries, respectively, than those achieved with a DTW-based system, with storage requirements between 15 and 142 times lesser and a processing speed between 274 and 926 times greater. The security of the system is also enhanced as only the representative features need to be stored, it being impossible to recover the original signature from these.Junta de Castilla y Leon (project VA077A08

Using challenges to enhance a learning game for pronunciation training of English as a second language

Producción CientíficaLearning games have a remarkable potential for education. They provide an emergent form of social participation that deserves the assessment of their usefulness and efficiency in learning processes. This study describes a novel learning game for foreign pronunciation training in which players can challenge each other. Native Spanish speakers performed several pronunciation activities during a one-month competition using a mobile application, designed under a minimal pairs approach, to improve their pronunciation of English as a foreign language. This game took place in a competitive scenario in which students had to challenge other participants in order to get high scores and climb up a leaderboard. Results show intense practice supported by a significant number of activities and playing regularity, so the most active and motivated players in the competition achieved significant pronunciation improvement results. The integration of automatic speech recognition (ASR) and text-to-speech (TTS) technology allowed users to improve their pronunciation while being immersed in a highly motivational game.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (grant TIN2014-59852-R)Junta de Castilla y Leon (grant VA050G18

IberSPEECH 2020: XI Jornadas en Tecnología del Habla and VII Iberian SLTech

IberSPEECH2020 is a two-day event, bringing together the best researchers and practitioners in speech and language technologies in Iberian languages to promote interaction and discussion. The organizing committee has planned a wide variety of scientific and social activities, including technical paper presentations, keynote lectures, presentation of projects, laboratories activities, recent PhD thesis, discussion panels, a round table, and awards to the best thesis and papers. The program of IberSPEECH2020 includes a total of 32 contributions that will be presented distributed among 5 oral sessions, a PhD session, and a projects session. To ensure the quality of all the contributions, each submitted paper was reviewed by three members of the scientific review committee. All the papers in the conference will be accessible through the International Speech Communication Association (ISCA) Online Archive. Paper selection was based on the scores and comments provided by the scientific review committee, which includes 73 researchers from different institutions (mainly from Spain and Portugal, but also from France, Germany, Brazil, Iran, Greece, Hungary, Czech Republic, Ucrania, Slovenia). Furthermore, it is confirmed to publish an extension of selected papers as a special issue of the Journal of Applied Sciences, “IberSPEECH 2020: Speech and Language Technologies for Iberian Languages”, published by MDPI with fully open access. In addition to regular paper sessions, the IberSPEECH2020 scientific program features the following activities: the ALBAYZIN evaluation challenge session.Red Española de Tecnologías del Habla. Universidad de Valladoli

App-based detection of vulnerable implementations of OTP SMS APIs in the banking sector

Producción CientíficaTwo Factor Authentication (2FA) using One Time Password (OTP) codes via SMS messages is widely used. In order to improve user experience, Google has proposed APIs that allow the automatic verification of the SMS messages without the intervention of the users themselves. They reduce the risks of user error, but they also have vulnerabilities. One of these APIs is the SMS Retriever API for Android devices. This article presents a method to study the vulnerabilities of these OTP exchange APIs in a given sector. The most popular API in the sector is selected, and different scenarios of interaction between mobile apps and SMS OTP servers are posed to determine which implementations are vulnerable. The proposed methodology, applied here to the banking sector, is nevertheless simple enough to be applied to any other sector, or to other SMS OTP APIs. One of its advantages is that it proposes a method for detecting bad implementations on the server side, based on analyses of the apps, which boosts reusability and replicability, while offering a guide to developers to prevent errors that cause vulnerabilities. Our study focuses on Spain’s banking sector, in which the SMS Retriever API is the most popular. The results suggest that there are vulnerable implementations which would allow cybercriminals to steal the users SMS OTP codes. This suggests that a revision of the equilibrium between ease of use and security would apply in order to maintain the high level of security which has traditionally characterized this sector.Publicación en abierto financiada por el Consorcio de Bibliotecas Universitarias de Castilla y León (BUCLE), con cargo al Programa Operativo 2014ES16RFOP009 FEDER 2014-2020 DE CASTILLA Y LEÓN, Actuación:20007-CL - Apoyo Consorcio BUCL