Despite the importance of anxiety measuring tools, there is no published data on the factor analytic structure of the Multidimensional Anxiety Scale for Children (MASC) in South African adolescents. The present study was an attempt to examine the factor structure of the MASC in South African adolescents, the factor structure equivalence for boys and girls and the correlation between MASC scores and scores on the Child Trauma Questionnaire (CTQ), Child PTSD Checklist Score, and the Beck Depression Inventory (BDI) to establish whether the MASC distinguishes between anxiety and other constructs. Available literature indicates that the MASC is invariant across gender and age and it shows excellent internal reliability and test-retest reliability (March Parker, Sullivan, Stallings & Comers, 1997). The MASC appears to measure separate dimensions of anxiety, which in turn makes it ideally suited to discriminate patterns of anxiety in children with anxiety disorders (Rynn et al., 2005). The MASC also correlates well with other measures of anxiety (Revised Children's Manifest Anxiety Scale [RCMAS] and Screen of Child Anxiety Related Emotional Disorders [SCARED]), less so with measures of depression (Children's Depression Inventory [CDI:]) and not at all with measures of disruptive behaviour (March et al., 1997; Muris, Merckelbach, Ollendick & King, 2002). Several studies across the world have confirmed the four-factor structure of the MASC and found its subscales to be reliable in several studies across the world (Olason, Sighvatsson & Smari, 2004; Rynn et al., 2005). A sample of 1078 grade 10 adolescents was selected to participate in this study. The adolescents were from nine different schools, representative of the socio-economic status and ethnic diversity of the region in the Cape Town metropole (South Africa). Principal Components Confirmatory Factor Analysis was conducted on MASC scores using a varimax rotation. Item bias analysis were used to determine gender equivalence and Pearson's correlation statistics were used to explore the correlation of MASC scores to CTQ, BDI, and Child PTSD Checklist scores. The results of the study confirm the MASC four-factor structure and its subscales were found to be reliable. The MASC performed the best out of four scales measuring anxiety or depression. Analysis showed that the four-factor structure applies equally well for males and females. Younger adolescents scored higher than older adolescents on the MASC total scale and no differences on the MASC total scale were found when comparisons of race were made. Item bias analysis showed no statistically or practically significant eta-squared (IJ') value, indicating no gender bias. In general, results in this sample show that the characteristics of the MASC are similar to the original factor structure found by March et al. (1997). The MASC appears to measure separate dimensions of anxiety, which in turn should make it ideally suited to discriminate patterns of anxiety in subgroups of children with anxiety disorders. It can be concluded that the MASC shows to be a valid and reliable measure of anxiety for South African adolescents. It can be recommended that the MASC is a clinically useful and reliable self-report scale for assessing anxiety in children and adolescents. / Thesis (M.A. (Clinical Psychology))--North-West University, Potchefstroom Campus, 2007.

Despite the importance of anxiety measuring tools, there is no published data on the factor analytic structure of the Multidimensional Anxiety Scale for Children (MASC) in South African adolescents. The present study was an attempt to examine the factor structure of the MASC in South African adolescents, the factor structure equivalence for boys and girls and the correlation between MASC scores and scores on the Child Trauma Questionnaire (CTQ), Child PTSD Checklist Score, and the Beck Depression Inventory (BDI) to establish whether the MASC distinguishes between anxiety and other constructs. Available literature indicates that the MASC is invariant across gender and age and it shows excellent internal reliability and test-retest reliability (March Parker, Sullivan, Stallings & Comers, 1997). The MASC appears to measure separate dimensions of anxiety, which in turn makes it ideally suited to discriminate patterns of anxiety in children with anxiety disorders (Rynn et al., 2005). The MASC also correlates well with other measures of anxiety (Revised Children's Manifest Anxiety Scale [RCMAS] and Screen of Child Anxiety Related Emotional Disorders [SCARED]), less so with measures of depression (Children's Depression Inventory [CDI:]) and not at all with measures of disruptive behaviour (March et al., 1997; Muris, Merckelbach, Ollendick & King, 2002). Several studies across the world have confirmed the four-factor structure of the MASC and found its subscales to be reliable in several studies across the world (Olason, Sighvatsson & Smari, 2004; Rynn et al., 2005). A sample of 1078 grade 10 adolescents was selected to participate in this study. The adolescents were from nine different schools, representative of the socio-economic status and ethnic diversity of the region in the Cape Town metropole (South Africa). Principal Components Confirmatory Factor Analysis was conducted on MASC scores using a varimax rotation. Item bias analysis were used to determine gender equivalence and Pearson's correlation statistics were used to explore the correlation of MASC scores to CTQ, BDI, and Child PTSD Checklist scores. The results of the study confirm the MASC four-factor structure and its subscales were found to be reliable. The MASC performed the best out of four scales measuring anxiety or depression. Analysis showed that the four-factor structure applies equally well for males and females. Younger adolescents scored higher than older adolescents on the MASC total scale and no differences on the MASC total scale were found when comparisons of race were made. Item bias analysis showed no statistically or practically significant eta-squared (IJ') value, indicating no gender bias. In general, results in this sample show that the characteristics of the MASC are similar to the original factor structure found by March et al. (1997). The MASC appears to measure separate dimensions of anxiety, which in turn should make it ideally suited to discriminate patterns of anxiety in subgroups of children with anxiety disorders. It can be concluded that the MASC shows to be a valid and reliable measure of anxiety for South African adolescents. It can be recommended that the MASC is a clinically useful and reliable self-report scale for assessing anxiety in children and adolescents. / Thesis (M.A. (Clinical Psychology))--North-West University, Potchefstroom Campus, 2007.

The field of image synthesis has seen significant progress recently, including great strides with generative models like Generative Adversarial Networks (GANs), Diffusion Models, and Transformers. These models have shown they can create high-quality images from a variety of text prompts. However, a comprehensive analysis that examines both their performance and possible biases is often missing from existing research. In this thesis, I undertake a thorough examination of several leading text-to-image models, namely Stable Diffusion, DALL-E Mini, Lafite, and Ernie-ViLG. I assess their performance in generating accurate images of human faces, groups, and specified numbers of objects, using both Frechet Inception Distance (FID) scores and R-precision as my evaluation metrics. Moreover, I uncover inherent gender or social biases these models may possess. My research reveals a noticeable bias in these models, which show a tendency towards generating images of white males, thus under-representing minorities in their output of human faces. This finding contributes to the broader dialogue on ethics in AI and sets the stage for further research aimed at developing more equitable AI systems. Furthermore, based on the metrics I used for evaluation, the Stable Diffusion model outperforms the others in generating images from text prompts. This information could be particularly useful for researchers and practitioners trying to choose the most effective model for their future projects. To facilitate further research in this field, I have made my findings, the related data, and the source code publicly available. / Master of Science / In my research, I explored how cutting-edge computer models, namely Stable Diffusion, DALL-E Mini, Lafite, and Ernie-ViLG, can create images from text descriptions, a process that holds exciting possibilities for the future. However, these technologies aren't without their challenges. An important finding from my study is that these models exhibit bias, e.g., they often generate images of white males more than they do of other races and genders. This suggests they're not representing our diverse society fairly. Among these models, Stable Diffusion outperforms the others at creating images from text prompts, which is valuable information for anyone choosing a model for their projects. To help others learn from my work and build upon it, I've made all my data, findings, and the code I used in this study publicly available. By sharing this work, I hope to contribute to improving this technology, making it even better and fairer for everyone in the future.

Um dos desafios que ainda precisa ser superado com o objetivo de melhorar o desempenho do controle preditivo (MPC) é a sua manutenção. Reidentificação do processo é uma das melhores opções disponíveis para atualizar o modelo interno do MPC, a fim de melhorar seu desempenho. No entanto, o processo de reidentificação é dispendioso. Pesquisadores propuseram dois métodos diferentes, capazes de detectar divergências entre o processo real e o seu modelo, através da análise de correlações parciais. Utilizando essas técnicas, ao invés de reidentificar todos os sub-modelos do processo, apenas algumas entradas com divergência significativas teriam que ser perturbadas e somente a parte degradada do modelo seria atualizada. Entretanto, não há informações suficientes e análises sobre a influência das estruturas de modelo nos resultados das correlações parciais. Além disso, apesar de ambas as abordagens serem eficientes na detecção de divergências significativas, elas não fornecem informações suficientes sobre a sua quantificação. Esta dissertação de mestrado demonstra que o método de Carlsson (2010) é uma solução particular do método de Badwe et al. (2009), quando os modelos utilizados no processo de identificação são estruturas FIR. Além disso, alguns outros tipos de estruturas serão estudados, de modo a verificar se eles são adequados para a análise da correlação parcial, com o objetivo de detectar esse tipo de divergência. Quanto à limitação da detecção do nível da divergência entre o modelo e a planta, este trabalho propõe um projeto inicial de um novo método para resolver este problema, através da adição de ruído branco off-line nos dados coletados do processo, com diferentes variações antes da análise da correlação parcial. Um estudo de caso simulado é mostrado, que confirma a eficácia desta nova técnica. Finalmente, são apresentadas as conclusões encontradas e as possibilidades para estudos futuros. / One of the challenges that still needs to be overcome in order to improve the performance of the model predictive control (MPC) is its maintenance. Re-identification of the process is one of the best options available to update the internal model of the MPC, in order to improve performance. However, re-identification is costly. Researchers have proposed two different methods able to detect plant mismatch through partial correlation analysis. Using these techniques, instead of re-identifying all the sub-models in the process, only a few inputs with significant mismatch would have to be perturbed and only the degraded portion of the model would be updated. Nevertheless, there is not enough information and analysis about the influence of the model structures for identification on partial correlation results. Besides, although both approaches are efficient in detecting significant mismatches, they do not provide enough information about its magnitude. This masters thesis demonstrates that the Carlssons method (2010) is a particular solution of the Badwe et al.s method, when the models used on the identification process are FIR structures. Moreover, some other types of structures will be analyzed in order to check if they are suitable for the partial correlation procedure to detect plant mismatches. Concerning the limitation of the detection the level of plant-mismatch, this thesis proposes a starting project of a new method to address this issue by adding offline white noise to the collected data from the process with different variances before analyzing the partial correlation. A simulation case study is shown that confirms the efficacy of this new technique. Finally, conclusions and possible future studies are presented.

Um dos desafios que ainda precisa ser superado com o objetivo de melhorar o desempenho do controle preditivo (MPC) é a sua manutenção. Reidentificação do processo é uma das melhores opções disponíveis para atualizar o modelo interno do MPC, a fim de melhorar seu desempenho. No entanto, o processo de reidentificação é dispendioso. Pesquisadores propuseram dois métodos diferentes, capazes de detectar divergências entre o processo real e o seu modelo, através da análise de correlações parciais. Utilizando essas técnicas, ao invés de reidentificar todos os sub-modelos do processo, apenas algumas entradas com divergência significativas teriam que ser perturbadas e somente a parte degradada do modelo seria atualizada. Entretanto, não há informações suficientes e análises sobre a influência das estruturas de modelo nos resultados das correlações parciais. Além disso, apesar de ambas as abordagens serem eficientes na detecção de divergências significativas, elas não fornecem informações suficientes sobre a sua quantificação. Esta dissertação de mestrado demonstra que o método de Carlsson (2010) é uma solução particular do método de Badwe et al. (2009), quando os modelos utilizados no processo de identificação são estruturas FIR. Além disso, alguns outros tipos de estruturas serão estudados, de modo a verificar se eles são adequados para a análise da correlação parcial, com o objetivo de detectar esse tipo de divergência. Quanto à limitação da detecção do nível da divergência entre o modelo e a planta, este trabalho propõe um projeto inicial de um novo método para resolver este problema, através da adição de ruído branco off-line nos dados coletados do processo, com diferentes variações antes da análise da correlação parcial. Um estudo de caso simulado é mostrado, que confirma a eficácia desta nova técnica. Finalmente, são apresentadas as conclusões encontradas e as possibilidades para estudos futuros. / One of the challenges that still needs to be overcome in order to improve the performance of the model predictive control (MPC) is its maintenance. Re-identification of the process is one of the best options available to update the internal model of the MPC, in order to improve performance. However, re-identification is costly. Researchers have proposed two different methods able to detect plant mismatch through partial correlation analysis. Using these techniques, instead of re-identifying all the sub-models in the process, only a few inputs with significant mismatch would have to be perturbed and only the degraded portion of the model would be updated. Nevertheless, there is not enough information and analysis about the influence of the model structures for identification on partial correlation results. Besides, although both approaches are efficient in detecting significant mismatches, they do not provide enough information about its magnitude. This masters thesis demonstrates that the Carlssons method (2010) is a particular solution of the Badwe et al.s method, when the models used on the identification process are FIR structures. Moreover, some other types of structures will be analyzed in order to check if they are suitable for the partial correlation procedure to detect plant mismatches. Concerning the limitation of the detection the level of plant-mismatch, this thesis proposes a starting project of a new method to address this issue by adding offline white noise to the collected data from the process with different variances before analyzing the partial correlation. A simulation case study is shown that confirms the efficacy of this new technique. Finally, conclusions and possible future studies are presented.

Tesis por compendio / [ES] La detección del lenguaje abusivo es una tarea que se ha vuelto cada vez más importante en la era digital moderna, donde la comunicación se produce a través de diversas plataformas en línea. El aumento de las interacciones en estas plataformas ha provocado un aumento de la aparición del lenguaje abusivo. Abordar dicho contenido es crucial para mantener un entorno en línea seguro e inclusivo. Sin embargo, esta tarea enfrenta varios desafíos que la convierten en un área compleja y que demanda de continua investigación y desarrollo. En particular, detectar lenguaje abusivo en entornos con escasez de datos presenta desafíos adicionales debido a que el desarrollo de sistemas automáticos precisos a menudo requiere de grandes conjuntos de datos anotados. En esta tesis investigamos diferentes aspectos de la detección del lenguaje abusivo, prestando especial atención a entornos con datos limitados. Primero, estudiamos el sesgo hacia palabras clave abusivas en modelos entrenados para la detección del lenguaje abusivo. Con este propósito, proponemos dos métodos para extraer palabras clave potencialmente abusivas de colecciones de textos. Luego evaluamos el sesgo hacia las palabras clave extraídas y cómo se puede modificar este sesgo para influir en el rendimiento de la detección del lenguaje abusivo. El análisis y las conclusiones de este trabajo revelan evidencia de que es posible mitigar el sesgo y que dicha reducción puede afectar positivamente el desempeño de los modelos. Sin embargo, notamos que no es posible establecer una correspondencia similar entre la variación del sesgo y el desempeño de los modelos cuando hay escasez datos con las técnicas de reducción del sesgo estudiadas. En segundo lugar, investigamos el uso de redes neuronales basadas en grafos para detectar lenguaje abusivo. Por un lado, proponemos una estrategia de representación de textos diseñada con el objetivo de obtener un espacio de representación en el que los textos abusivos puedan distinguirse fácilmente de otros textos. Por otro lado, evaluamos la capacidad de redes neuronales convolucionales basadas en grafos para clasificar textos abusivos. La siguiente parte de nuestra investigación se centra en analizar cómo el aumento de datos puede influir en el rendimiento de la detección del lenguaje abusivo. Para ello, investigamos dos técnicas bien conocidas basadas en el principio de minimización del riesgo en la vecindad de instancias originales y proponemos una variante para una de ellas. Además, evaluamos técnicas simples basadas en el reemplazo de sinónimos, inserción aleatoria, intercambio aleatorio y eliminación aleatoria de palabras. Las contribuciones de esta tesis ponen de manifiesto el potencial de las redes neuronales basadas en grafos y de las técnicas de aumento de datos para mejorar la detección del lenguaje abusivo, especialmente cuando hay limitación de datos. Estas contribuciones han sido publicadas en conferencias y revistas internacionales. / [CA] La detecció del llenguatge abusiu és una tasca que s'ha tornat cada vegada més important en l'era digital moderna, on la comunicació es produïx a través de diverses plataformes en línia. L'augment de les interaccions en estes plataformes ha provocat un augment de l'aparició de llenguatge abusiu. Abordar este contingut és crucial per a mantindre un entorn en línia segur i inclusiu. No obstant això, esta tasca enfronta diversos desafiaments que la convertixen en una àrea complexa i contínua de recerca i desenvolupament. En particular, detectar llenguatge abusiu en entorns amb escassetat de dades presenta desafiaments addicionals pel fet que el desenvolupament de sistemes automàtics precisos sovint requerix de grans conjunts de dades anotades. En esta tesi investiguem diferents aspectes de la detecció del llenguatge abusiu, prestant especial atenció a entorns amb dades limitades. Primer, estudiem el biaix cap a paraules clau abusives en models entrenats per a la detecció de llenguatge abusiu. Amb este propòsit, proposem dos mètodes per a extraure paraules clau potencialment abusives de col·leccions de textos. Després avaluem el biaix cap a les paraules clau extretes i com es pot modificar este biaix per a influir en el rendiment de la detecció de llenguatge abusiu. L'anàlisi i les conclusions d'este treball revelen evidència que és possible mitigar el biaix i que esta reducció pot afectar positivament l'acompliment dels models. No obstant això, notem que no és possible establir una correspondència similar entre la variació del biaix i l'acompliment dels models quan hi ha escassetat dades amb les tècniques de reducció del biaix estudiades. En segon lloc, investiguem l'ús de xarxes neuronals basades en grafs per a detectar llenguatge abusiu. D'una banda, proposem una estratègia de representació textual dissenyada amb l'objectiu d'obtindre un espai de representació en el qual els textos abusius puguen distingir-se fàcilment d'altres textos. D'altra banda, avaluem la capacitat de models basats en xarxes neuronals convolucionals basades en grafs per a classificar textos abusius. La següent part de la nostra investigació se centra en analitzar com l'augment de dades pot influir en el rendiment de la detecció del llenguatge abusiu. Per a això, investiguem dues tècniques ben conegudes basades en el principi de minimització del risc en el veïnatge d'instàncies originals i proposem una variant per a una d'elles. A més, avaluem tècniques simples basades en el reemplaçament de sinònims, inserció aleatòria, intercanvi aleatori i eliminació aleatòria de paraules. Les contribucions d'esta tesi destaquen el potencial de les xarxes neuronals basades en grafs i de les tècniques d'augment de dades per a millorar la detecció del llenguatge abusiu, especialment quan hi ha limitació de dades. Estes contribucions han sigut publicades en revistes i conferències internacionals. / [EN] Abusive language detection is a task that has become increasingly important in the modern digital age, where communication takes place via various online platforms. The increase in online interactions has led to an increase in the occurrence of abusive language. Addressing such content is crucial to maintaining a safe and inclusive online environment. However, this task faces several challenges that make it a complex and ongoing area of research and development. In particular, detecting abusive language in environments with sparse data poses an additional challenge, since the development of accurate automated systems often requires large annotated datasets. In this thesis we investigate different aspects of abusive language detection, paying particular attention to environments with limited data. First, we study the bias toward abusive keywords in models trained for abusive language detection. To this end, we propose two methods for extracting potentially abusive keywords from datasets. We then evaluate the bias toward the extracted keywords and how this bias can be modified in order to influence abusive language detection performance. The analysis and conclusions of this work reveal evidence that it is possible to mitigate the bias and that such a reduction can positively affect the performance of the models. However, we notice that it is not possible to establish a similar correspondence between bias mitigation and model performance in low-resource settings with the studied bias mitigation techniques. Second, we investigate the use of models based on graph neural networks to detect abusive language. On the one hand, we propose a text representation framework designed with the aim of obtaining a representation space in which abusive texts can be easily distinguished from other texts. On the other hand, we evaluate the ability of models based on convolutional graph neural networks to classify abusive texts. The next part of our research focuses on analyzing how data augmentation can influence the performance of abusive language detection. To this end, we investigate two well-known techniques based on the principle of vicinal risk minimization and propose a variant for one of them. In addition, we evaluate simple techniques based on the operations of synonym replacement, random insertion, random swap, and random deletion. The contributions of this thesis highlight the potential of models based on graph neural networks and data augmentation techniques to improve abusive language detection, especially in low-resource settings. These contributions have been published in several international conferences and journals. / This research work was partially funded by the Spanish Ministry of Science and Innovation under the research project MISMIS-FAKEnHATE on Misinformation and Miscommunication in social media: FAKE news and HATE speech (PGC2018-096212-B-C31). The authors thank also the EU-FEDER Comunitat Valenciana 2014-2020 grant IDIFEDER/2018/025. This work was done in the framework of the research project on Fairness and Transparency for equitable NLP applications in social media, funded by MCIN/AEI/10.13039/501100011033 and by ERDF, EU A way of making EuropePI. FairTransNLP research project (PID2021-124361OB-C31) funded by MCIN/AEI/10.13039/501100011033 and by ERDF, EU A way of making Europe. Part of the work presented in this article was performed during the first author’s research visit to the University of Mannheim, supported through a Contact Fellowship awarded by the DAAD scholarship program “STIBET Doktoranden”. / Peña Sarracén, GLDL. (2024). On the Keyword Extraction and Bias Analysis, Graph-based Exploration and Data Augmentation for Abusive Language Detection in Low-Resource Settings [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/203266 / Compendio