Classification of skateboarding tricks by synthesizing transfer learning models and machine learning classifiers using different input signal transformations

Skateboarding has made its Olympic debut at the delayed Tokyo 2020 Olympic Games. Conventionally, in the competition scene, the scoring of the game is done manually and subjectively by the judges through the observation of the trick executions. Nevertheless, the complexity of the manoeuvres executed has caused difficulties in its scoring that is obviously prone to human error and bias. Therefore, the aim of this study is to classify five skateboarding flat ground tricks which are Ollie, Kickflip, Shove-it, Nollie and Frontside 180. This is achieved by using three optimized machine learning models of k-Nearest Neighbor (kNN), Random Forest (RF), and Support Vector Machine (SVM) from features extracted via eighteen transfer learning models. Six amateur skaters performed five tricks on a customized ORY skateboard. The raw data from the inertial measurement unit (IMU) embedded on the developed device attached to the skateboarding were extracted. It is worth noting that four types of input images were transformed via Fast Fourier Transform (FFT), Continuous Wavelet Transform (CWT), Discrete Wavelet Transform (DWT) and synthesized raw image (RAW) from the IMU-based signals obtained. The optimized form of the classifiers was obtained by performing GridSearch optimization technique on the training dataset with 3-folds cross-validation on a data split of 4:1:1 ratio for training, validation and testing, respectively from 150 transformed images. It was shown that the CWT and RAW images used in the MobileNet transfer learning model coupled with the optimized SVM and RF classifiers exhibited a test accuracy of 100%. In order to identify the best possible method for the pipelines, computational time was used to evaluate the various models. It was concluded that the RAW-MobileNet-optimized-RF approach was the most effective one, with a computational time of 24.796875 seconds. The results of the study revealed that the proposed approach could improve the classification of skateboarding tricks

Sistema multimodal para análise automática do desempenho desportivo de atletas

Os sistemas multimodais são cada vez mais utilizados no contexto desportivo e este trabalho tem por objetivo demonstrar como a aprendizagem automática embebida na visão por computador aplicada ao contexto do boxe pode ajudar um praticante a melhorar a sua técnica e tempo de reação. Foi implementada uma aplicação utilizando ReactJS, que através da câmara consegue extrair dados sobre a postura do atleta num referencial de 2 dimensões por meio do modelo Posenet e que são posteriormente fornecidos a uma Rede Neuronal para os classificar como ”esquerda”, ”direita”, ”esquiva” ou ”guarda”. Foram recolhidas um total de 31425 amostras, incluindo movimentos de todas as classes alvo de classificação, sendo que o conjunto de dados está dividido em: 46% treino, 27% validação e 27% teste. Após o treino concluiu-se que a Rede Neuronal com afinação de hiper-parâmetros para 20 épocas foi o modelo que obteve melhor desempenho com uma Medida-F Média e Exatidão de 95%. Posteriormente o mesmo foi testado com o conjunto de teste e obteve uma Medida-F Média e Exatidão de 97.7% . A aplicação foi concebida no formato de um jogo em que o jogador terá de executar corretamente os movimentos que lhe serão pedidos de forma aleatória ao longo de 30 segundos. Tudo isto foi desenvolvido com o apoio de ferramentas de código aberto e sem necessidade de nenhum dispositivo adicional ao de um computador portátil ou tablet comum; Abstract: Multimodal system for automatic analysis of athletes sports peformance Multimodal systems are becoming mainstream in the context of sport and this work has the objective to show how machine learning embedded with computer vision can be applied to the context of boxing can help a praticioner by improving his technique and reaction time. A web application was implemented using ReactJS and uses the web cam to extract data about the posture of the athlete in a 2 dimensions referential, thanks to Posenet, that is posteriorly supplied to a Neural Network that uses it to classify each pose as a ”right”, ”left”, ”dodge” or ”guard”. A total of 31425 samples were collected, including all classes target of classification, divided in: 46% training, 27% validation and 27% test. After training, the Neural Network with the hyperparameter tuning for 20 epochs was the model with the best performance overall with an Average F-score and Accuracy of 95%. The same model was tested with the test set and obtained an Average F-score and Accuracy of 97.7%. The application was conceived in the format of a game in which the player will have to execute correctly the movements that will be demanded by the system in a random manner for 30 seconds. All this was developed with the support of open source tools and no need of any extra devices but a common laptop or a tablet

More than a Spasm, Less than a Sign: Queer Masculinity in American Visual Culture, 1915-1955

This research considers the contribution of visual culture to queer masculinity among white American men during a profound reorientation both in popular understandings and the practical conditions of eroticism between men. From about 1915 to 1955 a pragmatic libidinal economy centered on the theatrical effeminacy of “fairies” was displaced by one founded on the presumption of strongly delineated and relatively fixed hetero- and homo-sexual identities. Although medical discourses about queerness had been developing since the middle of the Nineteenth Century in Europe, what Americans of the opening decades of the twentieth century knew about queerness they learned unsystematically from hearsay, the observation of local people and practices, and visual culture. Photography and film built on existing representational conventions, such as those developed in painting, illustration, theatre and nightlife, but the voyeuristic position of the spectators of films and photographs provided a special liberty to look at men, fetishistically or critically, and imagine recreating their gestures in the medium of one’s own body. Gesture is understood here as the aestheticization of self-presence by means of the movement or disposition of the body and its props. Gestures articulate a selfhood that enjoys a conditional freedom in its relation to the social world while being subject to the structures of meaning it inherits and the operation of discipline. Through fine-grained analyses of queer gags in Charlie Chaplin’s slapstick comedy and nude figure studies by George Platt Lynes, this research argues that visual culture provided an apprenticeship in and theory of queer masculinity as a set of gestures. This study supplements the scholarly literature on Charlie Chaplin by foregrounding aspects of his star text that key audiences to recognize the masculinity of his signature Tramp as queer and cataloguing his use of dance, drag, and accident to provide a figure for homoeroticism in slapstick. It also significantly extends the existing critical literature on the photography of George Platt Lynes by considering camp, surrealism, and glamour as aspects of a decades-long engagement with the phenomenal texture of life as a middle-class queer American man

The role of semantic transparency and metaphorical elaboration through pictures for learning idioms in a second language

Idioms, as multi-word units that contain literal and figurative meanings, are inherently complex and thus unsurprisingly difficult to acquire for second language learners. Though experimental studies on idioms have been carried out with pedagogically minded foci, none have examined the differential effects picture type has on correct interpretation of meaning or meaning recall. Because idioms have both literal and figurative senses, they can be pictorially expressed via either or both of their dual meanings. However, no one has yet tested whether figurative elements in pictures will aid or confuse second language learners when presented alongside idioms. Thus, the primary aim of this thesis is to experimentally test how different kinds of pictures affect the way in which second language learners interpret and recall the figurative meaning of metaphorical idioms. Furthermore, the role of semantic transparency and how it impacts the effectiveness of the picture type is examined. The overarching finding suggests that metaphorically imbued pictures overall facilitate the learning of idioms. However, highly contextualized pictures have the potential to mislead learners in specific and often unpredictable ways. In addition to the pedagogical implications uncovered, this thesis also addresses the nature of semantic transparency and teacher attitudes on idioms

The Shape of Agency

In this book Shepherd offers a perspective on the shape of agency by offering interlinked explanations of the basic building blocks of agency, as well as its exemplary instances. In the book’s first part, he offers accounts of phenomena that have long troubled philosophers of action: control over behavior, non-deviant causation, and intentional action. These accounts build on earlier work in the causalist tradition and undermine the claims of many that causalism cannot offer a satisfying account of non-deviant causation, and therefore intentional action. In the book’s second part, he turns to modes of agentive excellence—ways that agents display quality of form. He offers a novel account of skill, including an account of the ways that agents display more or less skill. He discusses the role of knowledge in skill and concludes that while knowledge is often important, it is inessential. This leads to a discussion of knowledge of action—of the way that knowledge of action and knowledge of how to act informs action execution. Shepherd argues that knowledgeable action includes a unique epistemic underpinning. For in knowledgeable action, the agent has authoritative knowledge of what she is doing and how she is doing it when and because she is poised to control her action by way of practical reasoning

The Shape of Agency

In this book Shepherd offers a perspective on the shape of agency by offering interlinked explanations of the basic building blocks of agency, as well as its exemplary instances. In the book’s first part, he offers accounts of phenomena that have long troubled philosophers of action: control over behavior, non-deviant causation, and intentional action. These accounts build on earlier work in the causalist tradition and undermine the claims of many that causalism cannot offer a satisfying account of non-deviant causation, and therefore intentional action. In the book’s second part, he turns to modes of agentive excellence—ways that agents display quality of form. He offers a novel account of skill, including an account of the ways that agents display more or less skill. He discusses the role of knowledge in skill and concludes that while knowledge is often important, it is inessential. This leads to a discussion of knowledge of action—of the way that knowledge of action and knowledge of how to act informs action execution. Shepherd argues that knowledgeable action includes a unique epistemic underpinning. For in knowledgeable action, the agent has authoritative knowledge of what she is doing and how she is doing it when and because she is poised to control her action by way of practical reasoning

The Spatial Dimension of Narrative Understanding. Exploring Plot Types in the Narratives of Alessandro Baricco, Andrea Camilleri and Italo Calvino

The thesis explores the hypothesis that some plots might rely on spatiality as an organising principle that impacts on the narrative structure and, consequently, on the strategies adopted by readers to understand them. In order to lay the grounding for a spatially-oriented approach to narrative understanding, this study pursues both a theoretical line of inquiry and an applied line of inquiry in literary criticism. A cognitive stance on the nature of thought as non-propositional (Johnson-Laird 1983) and of the mind as embodied (Lakoff and Johnson 1999; Varela et al. 1993) provides the theoretical point of departure for the subsequent identification of a range of principles and frameworks that can be implemented to support a spatially-oriented interpretation according to the specificities of narratives. The three case studies provided by Alessandro Baricco’s City, Andrea Camilleri’s Montalbano crime series, and Italo Calvino’s Se una notte d’inverno un viaggiatore illustrate how a spatially-oriented perspective can add new interpretive angles and an unprecedented insight into the ways narratives achieve a coherent structure. At the same time, the case studies serve to extrapolate a set of features that constitute the preliminary criteria for assessing whether it would be fruitful to apply a spatially-oriented approach to a specific narrative. Baricco’s, Camilleri’s and Calvino’s works represent three plot types in which spatiality impinges in three different ways on the narrative, which, as I will show, can be epitomised by the image schemata of map, trajectory, and fractal. Far from simply referring to objects which plot is compared to, these images indicate procedural techniques and strategies of sense-making that a certain type of narrative is designed to prompt in the reader through textual cues. The study, in fact, builds on and advances a notion of plot to be analysed as a process rather than a given structure, something that readers understand as they read, and not retrospectively only