Learning motor skills from partially observed movements executed at different speeds

Learning motor skills from multiple demonstrations presents a number of challenges. One of those challenges is the occurrence of occlusions and lack of sensor coverage, which may corrupt part of the recorded data. Another issue is the variability in speed of execution of the demonstrations, which may require a way of finding the correspondence between the time steps of the different demonstrations. In this paper, an approach to learn motor skills is proposed that accounts both for spatial and temporal variability of movements. This approach, based on an Expectation-Maximization algorithm to learn Probabilistic Movement Primitives, also allows for learning motor skills from partially observed demonstrations, which may result from occlusion or lack of sensor coverage. An application of the algorithm proposed in this work lies in the field of Human-Robot Interaction when the robot has to react to human movements executed at different speeds. Experiments in which a robotic arm receives a cup handed over by a human illustrate this application. The capabilities of the algorithm in learning and predicting movements are also evaluated in experiments using a data set of letters and a data set of golf putting movements

M\"obius and twisted graphene nanoribbons: stability, geometry and electronic properties

Results of classical force field geometry optimizations for twisted graphene nanoribbons with a number of twists $N_t$ varying from 0 to 7 (the case $N_t$=1 corresponds to a half-twist M\"obius nanoribbon) are presented in this work. Their structural stability was investigated using the Brenner reactive force field. The best classical molecular geometries were used as input for semiempirical calculations, from which the electronic properties (energy levels, HOMO, LUMO orbitals) were computed for each structure. CI wavefunctions were also calculated in the complete active space framework taking into account eigenstates from HOMO-4 to LUMO+4, as well as the oscillator strengths corresponding to the first optical transitions in the UV-VIS range. The lowest energy molecules were found less symmetric than initial configurations, and the HOMO-LUMO energy gaps are larger than the value found for the nanographene used to build them due to electronic localization effects created by the twisting. A high number of twists leads to a sharp increase of the HOMO $\to$ LUMO transition energy. We suggest that some twisted nanoribbons could form crystals stabilized by dipolar interactions

Movement primitives with multiple phase parameters

Movement primitives are concise movement representations that can be learned from human demonstrations, support generalization to novel situations and modulate the speed of execution of movements. The speed modulation mechanisms proposed so far are limited though, allowing only for uniform speed modulation or coupling changes in speed to local measurements of forces, torques or other quantities. Those approaches are not enough when dealing with general velocity constraints. We present a movement primitive formulation that can be used to non-uniformly adapt the speed of execution of a movement in order to satisfy a given constraint, while maintaining similarity in shape to the original trajectory. We present results using a 4-DoF robot arm in a minigolf setup

A model of signaling for establishing of LSPs for multicast communication over GMPLS networks

Label switching, which in IP networks is exemplified by MPLS and its extensions MPLambdaS and GMPLS, appears as one of the best alternatives to offer a reliable and flexible control plane for WDM networks, since it allows the integration of the IP Protocol with WDM technology, when lambdas are associated with labels, implements powerful traffic-engineering mechanisms, and provides several alternative schemes for fault-tolerance, as well as support for quality of service (QoS). However, almost all the definitions and standardizations for MPLS are restricted to unicast communication, leaving support for multicast communication for future work. In the specific case of the triggering problem for LSPs (Label Switched Paths), there is still no consensus about the best strategy for multicast communication. This paper proposes an algorithm for traffic-driven triggering of LSPs, based on MFCs (Multicast Forwarding Caches), and has the advantage of being a schema which is compatible with several multicast routing protocols. To validate the proposed algorithm we carry out simulation studies using the NS-2 (Network Simulator) simulation platform.5th IFIP International Conference on Network Control & Engineering for QoS, Security and MobilityRed de Universidades con Carreras en Informática (RedUNCI

M\"obius and twisted graphene nanoribbons: stability, geometry and electronic properties

Results of classical force field geometry optimizations for twisted graphene nanoribbons with a number of twists $N_t$ varying from 0 to 7 (the case $N_t$=1 corresponds to a half-twist M\"obius nanoribbon) are presented in this work. Their structural stability was investigated using the Brenner reactive force field. The best classical molecular geometries were used as input for semiempirical calculations, from which the electronic properties (energy levels, HOMO, LUMO orbitals) were computed for each structure. CI wavefunctions were also calculated in the complete active space framework taking into account eigenstates from HOMO-4 to LUMO+4, as well as the oscillator strengths corresponding to the first optical transitions in the UV-VIS range. The lowest energy molecules were found less symmetric than initial configurations, and the HOMO-LUMO energy gaps are larger than the value found for the nanographene used to build them due to electronic localization effects created by the twisting. A high number of twists leads to a sharp increase of the HOMO $\to$ LUMO transition energy. We suggest that some twisted nanoribbons could form crystals stabilized by dipolar interactions

A mãe diante do inesperado: a perda do filho – uma discussão fenomenológica

Introduction: The experience of a young child’s loss repercuts on the whole family unit, specially for the mother figure, who does not expect that will have to deal with the death of her offspring. Thus, when the mother-child relationship is focused on the perspective of loss, one can observe the translation of iminent suffering and diffuse feelings that are intensely experienced in the search for re-signification. Objective: The present study aims to understand the meaning of the loss of a child from the mother’s point of view who experienced the diagnosis of brain death and authorized organ donation. Methods: The present study aims to understand the meaning of the loss of a child from the mother’s point of view who experienced the diagnosis of brain death and authorized organ donation. Results: The unveiling of the phenomenological narrative indicated the phenomenological construct: Death pervades the living-world that describes the difficulty of dealing with death, the moment of confirmation of loss, and the experience of mourning, as profound marks in the trajectory of the being-mother. However, it emerges in the discursiveness through the organ donation view that gives the mother the possibility of mourning the inexistence of the child but also its permanence in a body that is out of her experience range. Conclusion: The results point to reflections about new humanized practices in the health units. In order to reduce the impact of death communication with the establishment of a protocol for family care, which serves as a support system for families that experience the pain of loss and for re-signification of the moment of loss.Introdução: A experiência da perda de um filho jovem repercute em toda unidade familiar, especialmente, na figura da mãe que não espera lidar com a situação da morte filial. Assim, quando se enfoca a relação mãe-filho, na perspectiva da perda, observa-se a tradução do sofrimento iminente e sentimentos difusos que são vivenciados intensamente em busca da ressignificação. Objetivo: O presente estudo visa compreender o sentido e significado da perda de um filho pela ótica das mães que vivenciaram o momento do diagnóstico da morte encefálica e autorizaram a doação de órgãos. Métodos: A pesquisa é qualitativa com aplicação do método fenomenológico, utilizando como instrumento a entrevista fenomenológica com cinco mães de filhos que estavam na faixa etária entre 10 a 19 anos no período de 2012 a 2013 no estado do Amazonas. Resultados: O desvelamento das narrativas indicou o constructo fenomenológico: a morte perpassa o mundo-vivido da mãe, que descreve a dificuldade de lidar com a morte, o momento da confirmação da perda e a experiência do luto, como marcas profundas na trajetória do ser-mãe. Entretanto, emerge na discursividade o viés da doação de órgãos que agrega à mãe a possibilidade de vivenciar o luto não apenas na inexistência do filho, mas estar no lugar da permanência em outro corpo que não está em seu campo de experiência. Conclusão: Os resultados apontam para reflexões de novas práticas humanizadas nas unidades de saúde, a fim de amenizar o impacto da comunicação da morte com o estabelecimento de um protocolo para acolhimento familiar como suporte a dor vivenciada para ressignificar esse momento de perda

Adoecer com o filho: os modos de ser autêntica na vivência de um tratamento clínico gestacional

Introduction: In the phenomenological-existential perspective, to understand the being-sick requires a deep plunge into unconditional acceptance to the professional of the health team. Then, the psychologist must create conditions for reflection on the meaning of illness. Objective: Understanding the speeches of pregnant women in the process of hospitalization for clinical treatment, into the situation of falling-ill-with-the- child, in a public maternity hospital in the city of Manaus. Methods: Qualitative research, through health psychology and along the lines of existential phenomenology, rescued feelings and meanings from initial interviews. The audience was fourteen pregnants in medical treatment in a public hospital in the city of Manaus. The categories of analysis were based according to the book “Being and Time” by Martin Heidegger, which he outlines the concept about authenticity of being-in-the-world. Results: This study demonstrated the importance of health psychology inside a maternity hospital, as well as the specific relevance of monitoring of psychological demands on beds of clinical treatment. Conclusion: Through the reports collected, the person was seen in its entirety, not only his illness. Authenticity existed when they proved to be launched into the world, from the understanding of a being-sick with a becoming-to-be-healthy.Introdução: Na perspectiva fenomenológico-existencial, compreender o ser-doente exige do profissional da equipe de saúde um mergulhar profundo na aceitação incondicional do mesmo, na qual o psicólogo deve criar condições para a reflexão do significado do adoecer. Objetivo: Compreender o discurso de gestantes em processo de internação para tratamento clínico, diante da situação de adoecer-com- o-filho, em uma maternidade pública na cidade de Manaus. Métodos: Pesquisa qualitativa que, diante da psicologia hospitalar e nos moldes da fenomenologia existencial, resgatou a partir de entrevistas de acolhimento os sentimentos e significados apreendidos por 14 gestantes em processo de tratamento clínico em uma maternidade pública na cidade de Manaus. As categorias de análise foram baseadas de acordo com a obra “Ser e Tempo”, de Martin Heidegger, na qual delineia o conceito de autenticidade do ser-no-mundo. Resultados: O trabalho constatou a importância da psicologia da saúde dentro de uma maternidade, assim como a relevância específica do acompanhamento de demandas psicológicas em leitos de tratamento clínico gestacional. Conclusão: Mediante os relatos colhidos, foi visto o ser em sua totalidade, não somente sua enfermidade. A autenticidade existiu quando elas demonstraram estarem lançadas ao mundo, a partir da compreensão de um ser-doente com um vir-a- ser-saudável

Learning interaction for collaborative tasks with probabilistic movement primitives

This paper proposes a probabilistic framework based on movement primitives for robots that work in collaboration with a human coworker. Since the human coworker can execute a variety of unforeseen tasks a requirement of our system is that the robot assistant must be able to adapt and learn new skills on-demand, without the need of an expert programmer. Thus, this paper leverages on the framework of imitation learning and its application to human-robot interaction using the concept of Interaction Primitives (IPs). We introduce the use of Probabilistic Movement Primitives (ProMPs) to devise an interaction method that both recognizes the action of a human and generates the appropriate movement primitive of the robot assistant. We evaluate our method on experiments using a lightweight arm interacting with a human partner and also using motion capture trajectories of two humans assembling a box. The advantages of ProMPs in relation to the original formulation for interaction are exposed and compared

A model of signaling for establishing of LSPs for multicast communication over GMPLS networks

Label switching, which in IP networks is exemplified by MPLS and its extensions MPLambdaS and GMPLS, appears as one of the best alternatives to offer a reliable and flexible control plane for WDM networks, since it allows the integration of the IP Protocol with WDM technology, when lambdas are associated with labels, implements powerful traffic-engineering mechanisms, and provides several alternative schemes for fault-tolerance, as well as support for quality of service (QoS). However, almost all the definitions and standardizations for MPLS are restricted to unicast communication, leaving support for multicast communication for future work. In the specific case of the triggering problem for LSPs (Label Switched Paths), there is still no consensus about the best strategy for multicast communication. This paper proposes an algorithm for traffic-driven triggering of LSPs, based on MFCs (Multicast Forwarding Caches), and has the advantage of being a schema which is compatible with several multicast routing protocols. To validate the proposed algorithm we carry out simulation studies using the NS-2 (Network Simulator) simulation platform.5th IFIP International Conference on Network Control & Engineering for QoS, Security and MobilityRed de Universidades con Carreras en Informática (RedUNCI