Este trabalho envolve o emprego de recentes tecnologias ligadas a promissora área de Inteligência Computacional e a tradicional área de Processamento de Sinais Digitais. Tem por objetivo o desenvolvimento de uma aplicação especifica na área de Processamento de Voz: o reconhecimento de locutor. Inúmeras aplicações, ligadas principalmente a segurança e controle, são possíveis a partir do domínio da tecnologia de reconhecimento de locutor, tanto no que diz respeito a identificação quanto a verificação de diferentes locutores. O processo de reconhecimento de locutor pode ser dividido em duas grandes fases: extração das características básicas do sinal de voz e classificação. Na fase de extração, procurou-se aplicar os mais recentes avanços na área de Processamento Digital de Sinais ao problema proposto. Neste contexto, foram utilizadas a frequência fundamental e as frequências formantes como parâmetros que identificam o locutor. O primeiro foi obtido através do use da autocorrelação e o segundo foi obtido através da transformada de Fourier. Estes parâmetros foram extraídos na porção da fala onde o trato vocal apresenta uma coarticulação entre dois sons vocálicos. Esta abordagem visa extrair as características desta mudança do aparato vocal. Existem dois tipos de reconhecimento de locutor: identificação (busca-se reconhecer o locutor em uma população) e verificação (busca-se verificar se a identidade alegada é verdadeira). O processo de reconhecimento de locutor é dividido em duas grandes fases: extração das características (envolve aquisição, pré-processamento e extração dos parâmetros característicos do sinal) e classificação (envolve a classificação do sinal amostrado na identificação/verificação do locutor ou não). São apresentadas diversas técnicas para representação do sinal, como analise espectral, medidas de energia, autocorrelação, LPC (Linear Predictive Coding), entre outras. Também são abordadas técnicas para extração de características do sinal, como a frequência fundamental e as frequências formantes. Na fase de classificação, pode-se utilizar diversos métodos convencionais: Cadeias de Markov, Distância Euclidiana, entre outros. Além destes, existem as Redes Neurais Artificiais (RNAs) que são consideradas poderosos classificadores. As RNAs já vêm sendo utilizadas em problemas que envolvem classificações de sinais de voz. Neste trabalho serão estudados os modelos mais utilizados para o problema de reconhecimento de locutor. Assim, o tema principal da Dissertação de Mestrado deste autor é a implementação de um sistema de reconhecimento de locutor utilizando Redes Neurais Artificiais para classificação do locutor. Neste trabalho tamb6m é apresentada uma abordagem para a implementação de um sistema de reconhecimento de locutor utilizando as técnicas convencionais para o processo de classificação do locutor. As técnicas utilizadas são Dynamic Time Warping (DTW) e Vector Quantization (VQ). / This work deals with the application of recent technologies related to the promising research domain of Intelligent Computing (IC) and to the traditional Digital Signal Processing area. This work aims to apply both technologies in a Voice Processing specific application which is the speaker recognition task. Many security control applications can be supported by speaker recognition technology, both in identification and verification of different speakers. The speaker recognition process can be divided into two main phases: basic characteristics extraction from the voice signal and classification. In the extraction phase, one proposed goal was the application of recent advances in DSP theory to the problem approached in this work. In this context, the fundamental frequency and the formant frequencies were employed as parameters to identify the speaker. The first one was obtained through the use of autocorrelation and the second ones were obtained through Fourier transform. These parameters were extracted from the portion of speech where the vocal tract presents a coarticulation between two voiced sounds. This approach is used to extract the characteristics of this apparatus vocal changing. In this work, the Multi-Layer Perceptron (MLP) ANN architecture was investigated in conjunction with the backpropagation learning algorithm. In this sense, some main characteristics extracted from the signal (voice) were used as input parameters to the ANN used. The output of MLP, trained previously with the speakers features, returns the authenticity of that signal. Tests were performed with 10 different male speakers, whose age were in the range from 18 to 24 years. The results are very promising. In this work it is also presented an approach to implement a speaker recognition system by applying conventional methods to the speaker classification process. The methods used are Dynamic Time Warping (DTW) and Vector Quantization (VQ).

Our purpose with this thesis was to find biometric methods that can be used in access control of mobile access. The access control has two parts. Firstly, to validate the identity of the caller and, secondly, to ensure the validated user is not changed during the session that follows. Any solution to the access control problem is not available today, which means that anyone can get access to the mobile phone and the Internet. Therefore we have researched after a solution that can solve this problem but also on how to secure that no one else can take over an already validated session. We began to search for biometric methods that are available today to find them that would be best suited together with a mobile phone. After we had read information about them we did choose three methods for further investigation. These methods were Fingerprint Recognition, Iris Scan and Speaker Verification. Iris Scan is the method that is best suited to solve the authentication problem. The reasons for this are many. One of them is the uniqueness and stability of the iris, not even identical twins or the pair of the same individual has the same iris minutiae. The iris is also very protected behind eyelids, cornea and the aqueous humor and therefore difficult to damage. When it comes to the method itself, is it one of the most secure methods available today. One of the reasons for this is that the equal error rate is better than one in a million. However, this rate can be even better. It all depends on the Hamming Distance, which is a value that show how different the saved and temporarily template are, and what it is set to. To solve our session authentication, which was to make sure that no one else could take over a connected mobile phone, a sensor plate is the answer. This sensor will be able to sense for touch, heat and pulse. These three sensor measurements will together secure a validated session since the mobile phone will disconnect if the sensor looses its sensor data. There are, however, technological and other challenges to be solved before our proposed solutions will become viable. We address some of these issues in our thesis.

Dans le contexte des indépendances des anciennes colonies françaises, la verve poétique d’auteurs « engagés » tels qu’Aimé Césaire, Léopold Sédar Senghor ou Léon-Gontran Damas est indissociable de la dénonciation de la colonisation et du combat politique pour l’émancipation. Les intellectuels, les hommes de Lettres, de culture, les artistes condamnent fermement les impérialismes européens. Pour les tenants de la « Négritude », la poésie relaie le témoignage le plus évident de l’engagement politique et littéraire. Cette écriture poétique, construite à la fois sur des pratiques liées l’oralité héritées de l’Afrique et sur des formes prosodiques relativement classiques, fonde le lieu où l’on peut faire passer des messages politiques, tout en revendiquant une culture africaine. Introduire par la suite l’écriture romanesque en Afrique subsaharienne et y reprendre les thèmes de l’esclavage, de la colonisation, de l’aliénation du colonisé, du néocolonialisme deviennent des opérations en vue de processus constructeurs ; il s’agit d’ouvrir une vision nouvelle du monde, en imprimant à la langue française la trace créative de son auteur en ses représentations. On assiste donc à une revendication des nationalisations des littératures francophones. Ainsi de la littérature camerounaise ou de la littérature congolaise — par exemple, Ahmadou Kourouma dit contribuer à une littérature malinké. Tchicaya U. Tam’si affirme que si le français le colonise, il le colonise à son tour, car, paradoxalement, la révolte du colonisé s’appuie sur la langue française du colonisateur, tout en s’efforçant de déplacer celle-ci par l’écriture. La littérature d’expression française en Afrique subsaharienne est le lieu des différences, et des « différances » car elle porte la trace des multiples trajectoires sociologiques, et devient par sa diversité un lieu de créativité, de liberté et d’hybridité. Nous voyons aussi apparaître le roman de contestation politique contre les dictatures, la corruption, les guerres civiles, à l’exemple d’Ahmadou Kourouma écrivant Allah n’est pas obligé sans plus se préoccuper du canon de la langue, mais en pratiquant une « langue pourrie » pour décrire une guerre atroce. C’est une créativité semblable à celle qui est à l’origine du créole, du français petit-nègre, du camfranglais, et que la littérature d’Afrique subsaharienne explore. C’est dans cette perspective ouverte par les pratiques subversives de l’écriture et de la lecture que s’inscrit l’émancipation des femmes en Afrique. Calixthe Beyala est en ce sens emblématique de l’évolution du statut des femmes et de leur place dans la société, dépassant le clivage sexuel masculin/féminin. Ce processus prend sa source dans le mouvement d’ensemble des indépendances et du post-colonialisme. Ainsi les femmes se sont-elles illustrées par leur écriture, véritable prise de parole dans un espace public traditionnellement réservé aux hommes. Le roman des femmes écrivains en Afrique subsaharienne s’attache à décrire les pratiques traditionnelles, la polygamie, les mariages forcés. Ayant acquis une autonomie de parole, ces écrivains se donnent le pouvoir d’intervenir dans le débat public. Cette forme d’émancipation conquiert un langage traditionnellement réservé aux hommes. La langue violente, argotique, obscène ou pornographique n’est plus un monopole masculin. Elle est investie autrement par les écrivains femmes qui peuvent dès lors se dire elles-mêmes. / In the context of the independences of former French colonies, the poetic impetus of militant authors such as Aimé Césaire, Léopold Sédar Senghor or Léon-Gontran Damas is adamantly linked to the rebuttal of colonialism and to political activism. Intellectuals, writers, and artists strongly condemn European imperialisms. For the “Négritude” poets, poetry stands as the most obvious testimony of political and literary commitment. Their poetic works, relying both on oral practices inherited from Africa and on relatively classic prosodic styles, is the vehicle for political messages and reclaiming of African culture. Subsequently, novel writing in sub-Saharian Africa tackles more and more themes of slavery, colonization, colonial alienation, neo-colonialism, all of this becoming empowering processes. The question is to open on a renewed vision of the world, giving the French language a new creative trace, through the authors’ representation. Therefore, Francophone literature reclaims its singularity. This is especially true with Cameroon and Congo: for instance, Ahmadou Kourouma posits that his literature is malinké. Tchicaya U. Tam’si declares that if the French language is colonizing him, then he colonizes it in turn. The colonized rebellion paradoxically leans on the French colonizer language, while trying to displace and advance it through writing. Francophone literature in sub-Saharian Africa is the place of differences and of “différances”, for it bears the traces of many sociological reflexions, and becomes, through its diversity, a place for creativity, liberty and hybridity. We also witness the rise of political protest novel against dictatures, corruption, civil wars ; for example Ahmadou Kourouma, writing Allah n’est pas obligé, does not bother anymore with the rules of literature but excels in the practice of a “rotten language” to describe an atrocious war. This is a form of creativity similar to the one that give birth to creole, “français petit-nègre”, “camfranglais” and one that African sub-Saharian literature explore. It is in this perspective opened by subversive writing and reading practices that women emancipation in Africa takes place. The case of Calixthe Beyala, among others, illustrates this evolution of the status of women in society, beyond the sexual male/female divide. This process stems from post-colonialism and independentist movements gaining power and focus in the XXth century. Women distinguish themselves thanks to their writing and speech in a public sphere reserved to men. Novels written by sub-Saharian African women carefully describe traditional practices, polygamy, forced marriages. These writers, through their acquired freedom speech, have gained the power to participate in the public debate. This form of emancipation takes hold of a language and an art formerly reserved to men because of traditions. Violence, slang words, obscene or pornographic language are no longer part of a male monopoly on poetic language. This poetic creation is vested differently by women writers, who are therefore able to express themselves.

This thesis is related to the field of acoustic signal processing and its applications to emerging communication environments. Acoustic signal processing is a very wide research area covering the design of signal processing algorithms involving one or several acoustic signals to perform a given task, such as locating the sound source that originated the acquired signals, improving their signal to noise ratio, separating signals of interest from a set of interfering sources or recognizing the type of source and the content of the message. Among the above tasks, Sound Source localization (SSL) and Automatic Speech Recognition (ASR) have been specially addressed in this thesis. In fact, the localization of sound sources in a room has received a lot of attention in the last decades. Most real-word microphone array applications require the localization of one or more active sound sources in adverse environments (low signal-to-noise ratio and high reverberation). Some of these applications are teleconferencing systems, video-gaming, autonomous robots, remote surveillance, hands-free speech acquisition, etc. Indeed, performing robust sound source localization under high noise and reverberation is a very challenging task. One of the most well-known algorithms for source localization in noisy and reverberant environments is the Steered Response Power - Phase Transform (SRP-PHAT) algorithm, which constitutes the baseline framework for the contributions proposed in this thesis. Another challenge in the design of SSL algorithms is to achieve real-time performance and high localization accuracy with a reasonable number of microphones and limited computational resources. Although the SRP-PHAT algorithm has been shown to be an effective localization algorithm for real-world environments, its practical implementation is usually based on a costly fine grid-search procedure, making the computational cost of the method a real issue. In this context, several modifications and optimizations have been proposed to improve its performance and applicability. An effective strategy that extends the conventional SRP-PHAT functional is presented in this thesis. This approach performs a full exploration of the sampled space rather than computing the SRP at discrete spatial positions, increasing its robustness and allowing for a coarser spatial grid that reduces the computational cost required in a practical implementation with a small hardware cost (reduced number of microphones). This strategy allows to implement real-time applications based on location information, such as automatic camera steering or the detection of speech/non-speech fragments in advanced videoconferencing systems. As stated before, besides the contributions related to SSL, this thesis is also related to the field of ASR. This technology allows a computer or electronic device to identify the words spoken by a person so that the message can be stored or processed in a useful way. ASR is used on a day-to-day basis in a number of applications and services such as natural human-machine interfaces, dictation systems, electronic translators and automatic information desks. However, there are still some challenges to be solved. A major problem in ASR is to recognize people speaking in a room by using distant microphones. In distant-speech recognition, the microphone does not only receive the direct path signal, but also delayed replicas as a result of multi-path propagation. Moreover, there are multiple situations in teleconferencing meetings when multiple speakers talk simultaneously. In this context, when multiple speaker signals are present, Sound Source Separation (SSS) methods can be successfully employed to improve ASR performance in multi-source scenarios. This is the motivation behind the training method for multiple talk situations proposed in this thesis. This training, which is based on a robust transformed model constructed from separated speech in diverse acoustic environments, makes use of a SSS method as a speech enhancement stage that suppresses the unwanted interferences. The combination of source separation and this specific training has been explored and evaluated under different acoustical conditions, leading to improvements of up to a 35% in ASR performance. / Martí Guerola, A. (2013). Multichannel audio processing for speaker localization, separation and enhancement [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/33101 / TESIS

Thesis (M. Sc. (Computer Science)) -- University of Limpopo, 2021 / The task of automatic speaker recognition, wherein a system verifies or identifies speakers from a recording of their voices, has been researched for several decades. However, research in this area has been carried out largely on freely accessible speaker datasets built on languages that are well-resourced like English. This study undertakes automatic speaker recognition research focused on a low-resourced language, Sepedi. As one of the 11 official languages in South Africa, Sepedi is spoken by at least 2.8 million people. Pre-recorded voices were acquired from a speech and language national repository, namely, the National Centre for Human Language Technology (NCHLT), were we selected the Sepedi NCHLT Speech Corpus. The open-source pyAudioAnalysis python library was used to extract three types of acoustic features of speech namely, time, frequency and cepstral domain features, from the acquired speech data. The effects and compatibility of these acoustic features was investigated. It was observed that combining the three acoustic features of speech had a more significant effect than using individual features as far as speaker recognition accuracy is concerned. The study also investigated the performance of machine learning algorithms on low-resourced languages such as Sepedi. Five machine learning (ML) algorithms implemented on Scikit-learn namely, K-nearest neighbours (KNN), support vector machines (SVM), random forest (RF), logistic regression (LR), and multi-layer perceptrons (MLP) were used to train different classifier models. The GridSearchCV algorithm, also implemented on Scikit-learn, was used to deduce ideal hyper-parameters for each of the five ML algorithms. The classifier models were evaluated on recognition accuracy and the results show that the MLP classifier, with a recognition accuracy of 98%, outperforms KNN, RF, LR and SVM classifiers. A graphical user interface (GUI) is developed and the best performing classifier model, MLP, is deployed on the developed GUI intended to be used for real time speaker identification and verification tasks. Participants were recruited to the GUI performance and acceptable results were obtained

This paper is a study in the linguistic field of Second Language Acquisition (SLA), with some overlap in the relation of language and gender. Focus is placed on adults' experiences and feelings towards using their learned language in different scenarios and whether there are any substantial differences related to the sex of the learner. The main questions discussed are, firstly, how confident Swedish adults are when communicating in English in different scenarios with different recipients. Secondly, what factors there are and how these factors influence adults' feelings towards communicating in English. The paper compares a sample of female and male adults of varying ages from 23-70, who live in Sweden. Using quantitative and qualitative questions in a questionnaire paired with an interview, this paper examines the feelings towards communication in English among adults and how these feelings have changed since they were in school. The study research how language anxiety and motivation relates to learning and using a foreign language. The research also examines if these factors have any connection to the participant’s sex. Learning how the affective factors or individual differences change over time can aid future teachers of English in motivating and helping students struggling with learning English. At some point during their period of studies, most adults in the study reported that they felt language anxiety or lack of confidence. However, the findings of this study that most adults eventually outgrow such anxiety and develop confidence as they become older and use English more.

En este artículo, se analizan los comentarios positivos y negativos que se visualizan en la plataforma digital YouTube a raíz del debate por el proyecto de la Ley de La Preservación, Uso y Difusión de las Lenguas: discusión entre las congresistas peruanas Martha Hildebrandt y María Sumire, que se suscitó el 6 de setiembre de 2007. Mediante el Análisis Crítico del Discurso (Fairclough, 1995, Van Dijk, 1999, Wodak y Meyer, 2003), se estudian cómo los comentaristas generan discursos de discriminación y racismo al usar estrategias lingüísticas. Los discursos se dividen en dos grupos: uno a favor y en defensa del actuar de Martha Hildebrandt y el otro en contra del mismo personaje, pero en defensa de la parte contraria: María Sumire. En base a ello, se demuestra cómo a través de los comentarios realizados virtualmente se reproducen relaciones jerárquicas y se legitiman prácticas sociales excluyentes en relación con ambas congresistas, quienes representan imágenes sociales distintas. / In this article, we analyze the positive and negative comments displayed on the digital platform YouTube as a result of the debate on the Law on the Preservation, Use and Dissemination of Languages: discussion between Peruvian congresswomen Martha Hildebrandt and María Sumire, which took place on September 6, 2007. Through the Critical Discourse Analysis (Fairclough, 1995, Van Dijk, 1999, Wodak and Meyer, 2003), we study how commentators generate discourses of discrimination and racism when using linguistic strategies. The discourses are divided into two groups: one in favor and in defense of Martha Hildebrandt's action and the other against the same character, but in defense of the opposite party: Maria Sumire. Based on this, it is demonstrated how through the comments made virtually, hierarchical relations are reproduced and excluding social practices are legitimized in relation to both congressmen, who represent different social images.

This research seeks to develop further understandings of effectiveness of the  Japan Exchange and Teaching (JET)  Programme. The JET programme is an internationalisation programme of which employs primarily native English language speakers into the role of Assistant Language Teachers of whom aid in teaching English within school settings across Japan. Inspiration to undertake the project arose through an observation that previous research into the JET programme displays an overwhelmingly negative perspective of the programme’s effectiveness, not least due to the consistent reduction in Japan’s perceived foreign language attainment rates in recent years. This study seeks to develop a new angle of understanding regarding the JET programme, namely through analysing its Assistant Language Teacher’s and Japanese Teachers of English’s perceptions of their own experiences within the programme, and what they each determine effectiveness to be within their own roles. These perceptions were elicited through joint interviews with pairs of Assistant Language Teachers and Japanese Teachers of English of whom work or worked together. Four interviews took place harbouring two participants in each, totalling eight participants. Through utilisation of thematic and multimodal analytical methodologies in tandem, participant pairs’ individual and collaboratively created perspectives were attained. Results displayed the importance of individual relationships towards effectiveness within participants’ working lives. Effectiveness was primarily displayed through empathetic understanding and supporting one another, alongside actions of which allowed participants to challenge the JET programme together and empower their own relationships in the process. Further, theoretical frameworks of language teacher effectiveness are utilised and display intriguing results pertaining to how participants fulfil their working roles, and how these roles act in empowering potentially problematic norms of what a native speaker is.

Small-signal moving-coil loudspeaker driver parameters are traditionally derived through electrical impedance measurement techniques. These parameters are commonly called Thiele/Small parameters, after Neville Thiele and Richard Small who are credited with developing industry-standard loudspeaker modeling techniques. However, because loudspeaker drivers are electro-mechano-acoustical transducers, it should be possible to measure their parameters in physical domains other than the electrical domain. A method of measuring loudspeaker parameters from the acoustical domain will be developed. The technique uses a plane wave tube to measure acoustical properties of a baffled driver under test. Quantities such as the transmission loss through the driver are measured for a driver placed in the tube using the two-microphone transfer-function technique. Models have been developed to curve fit the resulting data, from which small-signal loudspeaker parameters are subsequently derived. This thesis discusses the acoustical measurement theory, apparatus, and system modeling methods (via equivalent circuits). It also compares measured parameters to those derived using electrical techniques. Parameters derived from both approaches are compared with reference values to establish bias errors. Sequential measurements are also compared to reveal random errors in the derivation processes.

Treating Sandra Cisneros' The House on Mango Street and Chang-rae Lee's Native Speaker as Erziehungsroman—that is, stories whose coming-of-age process depends on the characters' education—reveals the similar process that both Esperanza Cordero and Henry Park experience as they navigate the 1960s and 1970s American school system. The most important obstacle in Esperanza's and Henry's ability to achieve academically is the contract of vagueness, the tacit agreement between federal education policy and English language learning (ELL) students to misunderstand one another. Differing cultural conceptions of education perpetuate this mutually detrimental relationship between education policy and ELL students, forcing Henry and Esperanza to choose between satisfying the cultural expectations of their ethnic communities and fulfilling the cultural expectations of their schools, a decision which initially appears mutually exclusive. Exacerbated by their school experiences, both Henry and Esperanza go through a process of rejecting and reclaiming their ethnicity as they come to terms with their ethnic identity. That both characters eventually turn to social advocacy as a solution not only to their own educational struggles but also to the ghettoization of their ethnic communities suggests cosmopolitanism as a solution to the constraints of the contract of vagueness, both for Henry and Esperanza and for their ethnic communities.