Browsing by Author "Torres, Felipe "

Now showing 1 - 6 of 6
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    Historical Time and Acceleration. A Constitutive Bond
    (2024) Torres, Felipe
    This manuscript addresses the link between the concept of `historical time' and the thesis of the acceleration of history and society in constitutive terms. `Historical time' is used as concept mainly from the eighteenth century and corresponds to a way of understanding the contemporary world as a moment in which a `chronology' of time and, along with it, the appearance of a temporalized history itself, take place. Different temporal schemes support this transition: a pass from synchronicity to diachrony, the transition from iteration to the `event, circularity to the linearity. In what follows, I propose to observe some implications and articulations of the `historical time' and `social acceleration' theses, advancing the hypothesis that they are both connected and mutual dependent.
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    Identification of the factors associated with the severity of the speech production problems in children with comorbid speech sound disorder and developmental language disorder
    (2020) Torres, Felipe; Fuentes-Lopez, Eduardo; Fuente, Adrian; Sevilla, Fabiana
    It has been suggested that factors such as auditory perception, oral motor skills, phonological awareness, and working memory are all associated with speech production problems in children with speech sound disorder (SSD) and developmental language disorder (DLD). However, it remains unclear whether the severity of the speech production problems in these children can be explained by an interaction among the aforementioned factors. The aim of this study was to determine which of these four factors best explain the severity of the speech production problems in children with SSD and DLD and whether an interaction between factors occurs. Forty-one children with SSD and DLD between 5 and 5;11 years old were selected. The number of phonological process errors was used as a measure of the severity of the speech production problems. The association between the number of phonological process errors and performance in auditory perception, oral motor skills, phonological awareness, and working memory along with the severity of the DLD was explored using univariate and multivariate regression models (with and without an interaction term). The results showed that the number of phonological process errors was largely explained by working memory and phonological awareness. An interaction between these two factors was also found. This means that working memory and phonological awareness interact to have an effect on the number of phonological process errors that is more than the sum of their parts.
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    Robust Nonlinear Model Predictive Control for the Trajectory Tracking of Skid-Steer Mobile Manipulators with Wheel-Ground Interactions
    (MDPI, 2024) Aro, Katherine; Guevara, Leonardo; Torres Torriti, Miguel Attilio; Torres, Felipe; Prado, Alvaro
    This paper presents a robust control strategy for trajectory-tracking control of Skid-Steer Mobile Manipulators (SSMMs) using a Robust Nonlinear Model Predictive Control (R-NMPC) approach that minimises trajectory-tracking errors while overcoming model uncertainties and terra-mechanical disturbances. The proposed strategy is aimed at counteracting the effects of disturbances caused by the slip phenomena through the wheel-terrain contact and bidirectional interactions propagated by mechanical coupling between the SSMM base and arm. These interactions are modelled using a coupled nonlinear dynamic framework that integrates bounded uncertainties for the mobile base and arm joints. The model is developed based on principles of full-body energy balance and link torques. Then, a centralized control architecture integrates a nominal NMPC (disturbance-free) and ancillary controller based on Active Disturbance-Rejection Control (ADRC) to strengthen control robustness, operating the full system dynamics as a single robotic body. While the NMPC strategy is responsible for the trajectory-tracking control task, the ADRC leverages an Extended State Observer (ESO) to quantify the impact of external disturbances. Then, the ADRC is devoted to compensating for external disturbances and uncertainties stemming from the model mismatch between the nominal representation and the actual system response. Simulation and field experiments conducted on an assembled Pioneer 3P-AT base and Katana 6M180 robotic arm under terrain constraints demonstrate the effectiveness of the proposed method. Compared to non-robust controllers, the R-NMPC approach significantly reduced trajectory-tracking errors by 79.5% for mobile bases and 42.3% for robot arms. These results highlight the potential to enhance robust performance and resource efficiency in complex navigation conditions.
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    Slowing Down Society? Theoretical Reflections on Social Deceleration in Pandemic Times (and Beyond)
    (2022) Torres, Felipe; Gros, Alexis
    The COVID-19 pandemic has caused a major change in everyday life and also rein-vigorated the theoretical and political discussion on the temporal rhythms of social existence. Taking the situation of the coronavirus crisis as a starting point, the present paper attempts to provide the outlines of a theoretical account of social deceleration, a topic that has been hitherto barely explored in the field of social studies of time. In view of the complexity of the phenomenon, a distinction is made between two ways of theoretically approaching it, namely, a descriptive and a normative perspective. The paper proceeds in three steps: First, upon adopting a descriptive perspective, it advances a definition of social deceleration and proposes a typology of its different manifestations. The second step analyzes the coronavirus crisis as a process of partial deceleration of social life. The final step gives an overview of the current normative, i.e., ethical-political, disputes over social speed.
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    Speeding up Collective Action. Theoretical Affinities between Conflict Studies and Acceleration Theory
    (2021) Torres, Felipe
    Acceleration theory has emphasized the alienation that results from the speeding up of social life, but it has paid less attention to other emancipatory goals. Is it possible to consider collective action and conflicts as an acceleration motor? If so, is it a contingent-situated motivation or rather a structural condition? The paper's hypothesis is that conflicts are deemed a contingent or structural acceleration motor depending on the very basic theoretical starting-point: 1) if conflicts are considered as an "exception" or an "anomaly" to be solved in an assumed "normal" course of society (functionalism), there is no structural acceleration condition for them, but rather a contextual one. Conversely, 2) if conflicts are perceived as a constitutive part of modern capitalist society, they can also be understood as an acceleration motor underpinning social life with emancipatory potential.
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    The Stochastic Transport Dynamics of a Conserved Quantity on a Complex Network
    (2018) Medina, Pablo ; Clark, Jaime; Kiwi, Miguel ; Torres, Felipe ; Rogan, José; Valdivia, Juan Alejandro