An error based mathematical module to enhance learning in signals and systems

During the last years, the lecturers at the Circuits and Systems Engineering Department at the E.U.I.T. de Telecomunicación at the Universidad Politécnica de Madrid are observing more and more serious mathematical errors in the different exams and exercises taken by the students. Although some of these mistakes can be considered unacceptable in engineering disciplines, it is possible for a student to pass the final exam regardless of these mistakes. In this scenario, and aware that results were getting worse and worse year after year, it was considered convenient, and almost indispensable, to develop math exercises that students must practice if they want to progress following a continuous and formative assessment method along their engineering studies. The first part of this work is to analyze basic mathematical errors in final exam exercises of the course “Signals and Systems”. We present and illustrate the most relevant errors detected during the last two years final exams of that course. The information obtained permits us to identify the main lacks, difficulties and defaults of the students. The second part of this work is to develop a training module in order to the students can practice as many times as they want with simple exercises dealing with the topics where frequent errors are detected. After practicing they must pass an initial test to make sure that students have acquired the adequate basic mathematical background and skills to progress successfully in the mentioned course. The questions and exercises have been written using different formats, most of them to be compatible with Moodle platform requirements

Preprocesado Avanzado de Imágenes Laríngeas para Mejorar la Segmentación del Área Glotal

El presente trabajo describe un método avanzado de preprocesado de imagen para mejorar la detección automática del espacio glotal en imagines laríngeas. El sistema puede aplicarse a imágenes obtenidas a partir de exploraciones de alta velocidad o a partir de exploraciones estroboscópicas (baja velocidad), aunque es en estas últimas donde se observan las mayores ventajas, al tratarse de grabaciones de inferior calidad. Con esta nueva técnica de preprocesado se logran resolver ciertos fallos de segmentación producidos por un sistema previo basado en transformada “Watershed” y “Merging”. En resumen, se consiguen arreglar o mejorar el 38% de los errores de delineado de la glotis que aparecían en 29 imágenes de un total de 111 segmentadas

Learning English is fun! Increasing motivation through video games

In this paper we present a study made with 16 university students with different levels of proficiency in English, who were divided into two groups: those with a basic level (B1 or lower) and those who had an advanced one (B2 or higher). These two groups had the opportunity to get to know and interact with a serious game developed in the ?Universidad Politécnica de Madrid? with the aim of helping in the teaching-learning process of English as a foreign language. Before and after the interaction, all students were interviewed on various aspects related to the English learning process. Although the results show some differences in the two groups, they mainly agree in that the use of the video game greatly increases their motivation to learn English, even though they also consider that they would be able to reach the same English level studying in a more traditional way. In addition, when the students were straightly asked about the usefulness of the video game to learn English, their answers in a graded scale of agreement, ranging from 1 to 5, had an average value of 3.76

MedivozCaptura. Una aplicación en red segura de ayuda al profesional de ORL

MedivozCaptura es una herramienta informática desarrollada para asistir al análisis y detección de patologías vocales. Se basa en el almacenamiento en una base de datos relacional de señales de voz, electroglotogramas (EGG) y vídeoendoscopias, además de otros datos sobre los pacientes que los especialistas puedan considerar relevantes. El presente documento describe el funcionamiento de la aplicación de forma distribuida en red, con la base de datos centralizada, así como la problemática de seguridad y rendimiento que supone la distribución a través de la red o Internet y cómo se solventa en MedivozCaptur

Competence assessment of final year projects for undergraduate telecommunication students

The value of project-based learning has lead to the inclusion of project development activities in engineering courses, being the Final Year Project (FYP) the most remarkable one. Several approaches have been proposed for assessing and grading FYPs but, among them, rubrics are becoming a standard for such type of assessment. However, due to the different characteristics and orientations of the projects (some are more practically oriented, some more theoretically), and the high amount of different competences to be evaluated (knowledge, working capability, communication skills, etc.), the definition of one unique rubric suitable for the evaluation of all FYPs presented in different degree programs, is a big challenge. In a former work, the educational outcomes expected from the FYP were defined and resulted in a proposal for their assessment. Afterwards, the proposal has been tested during one year within an educational innovation-project at the Universidad Politécnica de Madrid which involved the follow-up of 8 undergraduate telecommunication students elaborating their FYPs. In this publication, our experience will be described, based on the emerging work taking place through the formalisation of the process which consisted in the following steps: i) establishment of a schedule for the whole process (publication of FYPs topics, selection of applying students and their enrolment, assignation of a jury to each FYP, elaboration and follow-up of FYPs, final report submission, oral presentation, etc.); ii) design of rubrics for each of three assessment parts: working process, final report and oral presentation; and iii) follow-up and evaluation of the involved FYPs. Finally, problems that appeared during this experience (e.g. administrative aspects, criticisms and suggestions from the students, tutors and juries involved) are discussed and some modifications in the assessment system will be proposed in order to solve or minimize these problems

Cuestionarios online como herramienta de aprendizaje: comparación de resultados con diversos modelos de cuestionarios.

En este trabajo se comparan dos estrategias de evaluación a través de cuestionarios online: i) realizar un cuestionario de evaluación sumativa al final de cada bloque temático del curso o ii) permitir que, para cada bloque temático, el alumno pueda repetir varias veces un test (con realimentación de las respuestas correctas) y realizar un test similar después de esta fase de aprendizaje. Los resultados muestran varios beneficios de la segunda estrategia: una mayor participación de los alumnos hasta el final del semestre, una menor tasa de abandono de la asignatura y una mejor nota en los test. Sin embargo, para que el aprendizaje sea efectivo en el caso de repetir varias veces un test, se necesita un banco de preguntas suficientemente amplio para que exista una probabilidad baja de que las preguntas no se repitan. Este problema se ha resuelto utilizando la posibilidad que presentan algunas plataformas de gestión del aprendizaje de generar automáticamente variantes numéricas de una misma pregunta. Por último se observa un grado de acuerdo muy elevado por parte de los alumnos con el peso que los resultados de los tests tienen en la nota final del curso, en el caso bajo estudio. Abstract: This work compares two different assessment strategies through online tests: i) summative assessment tests at the end of each part of the course or ii) the students can do selfassessment tests (with feedback) prior to a summative assessment test at the end of each part of the course. Results show that the second strategy yields several benefits: an increment in student participation till the end of the semester, a reduction in the drop-out rate and an increase in the mean test marks. However, a large item bank is necessary to effectively implement this second strategy. This problem has been addressed by using the automatic item generation facility offered by several learning management systems. Finally, a high proportion of the students agree with the weight proposed for these tests in the final course mark

What can we learn from voice therapy of the speaking voice for singers's voice?

Voice therapies of muscle tension dysphonia in Germany need to be increased in effectiveness by applying intensive, manualized procedures and standardized assessment protocols. The same holds true for therapies of disturbed singer's voices. According to a Cochrane review on the effectiveness of therapies of functional dysphonia neither direct nor indirect voice therapies alone but combinations of both elements are effective (Ruotsalainen et al., 2007)

Síntesis multilocutor aplicando técnicas de conversión de hablante

Las técnicas de conversión de locutor transforman la señal de voz pronunciada por una persona para que sea percibida como si la hubiera dicho otra persona. Se denomina locutor fuente al hablante inicial y locutor deseado a la identidad que se pretende obtener. Tradicionalmente la transformación se aplica al habla natural o al habla sintética como un procesado posterior a la síntesis. El objetivo de esta tesis es estudiar las técnicas propuestas hasta el momento e incorporarlas en un sistema de síntesis de voz. Por ello es necesario conocer a fondo el método de síntesis a utilizar y estudiar y desarrollar la técnica que mejor se adapte a sus características. Se han estudiado dos propuestas de sintetizador: 1. Sintetizador de formantes que concatena unidades parametrizadas. En este caso los parámetros que se utilizan para la síntesis son los cinco primeros formantes y cuatro parámetros de fuente glotal del modelo LF (Liljencrants & Fant). 2. El segundo de los sintetizadores es un sintetizador LP (Linear Prediction) que concatena unidades codificadas. El modelo de fuente utilizado es un polinomio de sexto orden para modelar la integral del residuo y un filtro posterior para añadir riqueza frecuencial a la señal. En ambos casos se han desarrollado o modificado las herramientas necesarias para realizar el análisis de 455 unidades correspondientes a cuatro locutores: dos hombres y dos mujeres. Las técnicas de conversión utilizadas son: 1. Para el sintetizador por formantes se aplica una transformación lineal para convertir los cinco primeros formantes y copiamos los parámetros del modelo LF del locutor deseado. 2. En el caso del sintetizador LP la técnica de transformación empleada es la del mapeado de codebooks para acercar lo máximo los coeficientes LPC (Linear Prediction Coefficients) del locutor base a los del locutor deseado y en este caso se mantiene la fuente del locutor base. Se ha estudiado la relevancia de los parámetros utilizados en la síntesis por formantes en cuanto a la identidad del locutor se refiere. La conclusión de dicho estudio nos indica que la información sobre la identidad del locutor está repartida entre todos los parámetros analizados siendo los más relevantes la frecuencia fundamental, F0, y las frecuencias formánticas. Se ha modificado la fuente del sintetizador LP para favorecer la transformación del locutor. Se ha comprobado que el modelo de fuente propuesto mantiene una calidad equivalente al sintetizador que utiliza las unidades codificadas CELP (Coded Excited Linear Prediction). Se han realizado pruebas objetivas y subjetivas para evaluar la capacidad de transformar el hablante y la calidad de la voz sintetizada. Se demuestra que las técnicas empleadas son eficientes a la hora de cambiar la identidad del locutor pero también se observa una degradación de la calidad de la voz. ABSTRACT Voice conversion technologies transform the voice uttered by a person (source speaker) in order that it is perceived as if another person had said it (target speaker). Traditionally the transformation is applied to the natural speech or to the synthetic speech as a post-processing block for a synthesizer. The aim of this thesis is to study the technologies in the state of the art and to incorporate them in a system of synthesis of voice. To achieve this goal it is necessary to know thoroughly the method of synthesis to use, study and develop the technology that better adapts to its characteristics. Two types of synthesizer have been studied: 1. Formant synthesizer that concatenates parametrized units. In this case the parameters that are used for synthesis are the first five formants and four glottal source parameters of the model LF(Liljencrants and Fant). 2. The second one is a LP(Linear Prediction) synthesizer that concatenates codified units. The source model is a polynomial of sixth order to shape the integral of the LP residue and a later filter to enhace high frequencies. In both cases tools have been developed or modified to analize 455 units corresponding to four speakers: two men and two women. The voice conversion techniques develop in each synthesizer are: 1. A linear transformation is applied to convert the formants and we copy the LF model parameters of the target speaker. 2. In case of the LP synthesizer the technology used for transformation is codebook mapping. The relevancy of the parameters used in the formant synthesizer has been studied as far as speaker identity is concerned. The conclusion of the above mentioned study indicates that the information about the speaker identity is distributed among all the analyzed parameters being the most relevant the fundamental frequency, F0, and the formant frequencies. The source model of the LP synthesizer has been modified to favor speaker transformation. There has been verified that the proposed source model supports a equivalent quality to the synthesizer that uses codified units CELP (Coded Excited Linear Prediction). Objective and subjective tests have been carried out to evaluate the ability to transform the speaker and the quality of the synthesized voice. There is demonstrated that the used technologies are efficient at the moment of changing the identity of the speaker but it is also observed a degradation of the quality of the synthetic voice

Evidence-based Medicine Search: a customizable federated search engine

Purpose: This paper reports on the development of a tool by the Arizona Health Sciences Library (AHSL) for searching clinical evidence that can be customized for different user groups