Interactive Imitation Learning of Bimanual Movement Primitives

Performing bimanual tasks with dual robotic setups can drastically increase the impact on industrial and daily life applications. However, performing a bimanual task brings many challenges, like synchronization and coordination of the single-arm policies. This article proposes the Safe, Interactive Movement Primitives Learning (SIMPLe) algorithm, to teach and correct single or dual arm impedance policies directly from human kinesthetic demonstrations. Moreover, it proposes a novel graph encoding of the policy based on Gaussian Process Regression (GPR) where the single-arm motion is guaranteed to converge close to the trajectory and then towards the demonstrated goal. Regulation of the robot stiffness according to the epistemic uncertainty of the policy allows for easily reshaping the motion with human feedback and/or adapting to external perturbations. We tested the SIMPLe algorithm on a real dual-arm setup where the teacher gave separate single-arm demonstrations and then successfully synchronized them only using kinesthetic feedback or where the original bimanual demonstration was locally reshaped to pick a box at a different height

Polish device for FOCCoS/PFS slit system

The Fiber Optical Cable and Connector System, FOCCoS, for the Prime Focus Spectrograph, PFS, is responsible for transporting light from the Subaru Telescope focal plane to a set of four spectrographs. Each spectrograph will be fed by a convex curved slit with 616 optical fibers organized in a linear arrangement. The slit frontal surface is covered with a special dark composite, made with refractory oxide, which is able to sustain its properties with minimum quantities of abrasives during the polishing process; this stability is obtained This stability is obtained by the detachment of the refractory oxide nanoparticles, which then gently reinforce gently the polishing process and increase its the efficiency. The surface roughness measured in several samples after high performance polishing was about 0.01 microns. Furthermore, the time for obtaining a polished surface with this quality is about 10 times less than the time required for polishing a brass, glass or ceramic surface of the same size. In this paper, we describe the procedure developed for high quality polishing of this type of slit. The cylindrical polishing described here, uses cylindrical concave metal bases on which glass paper is based. The polishing process consists to use grid sequences of 30 microns, 12 microns, 9 microns, 5 microns, 3 microns, 1 micron and, finally, a colloidal silica on a chemical cloth. To obtain the maximum throughput, the surface of the fibers should be polished in such a way that they are optically flat and free from scratches. The optical fibers are inspected with a microscope at all stages of the polishing process to ensure high quality. The efficiency of the process may be improved by using a cylindrical concave composite base as a substrate suitable for diamond liquid solutions. Despite this process being completely by hand, the final result shows a very high quality

Economic burden of colorectal and breast cancers attributable to lack of physical activity in Brazil

Background: The increasing number of cancer patients has an escalating economic impact to public health systems (approximately, International dollars- Int$60 billion annually in Brazil). Physical activity is widely recognized as one important modifiable risk factor for cancer. Herein, we estimated the economic costs of colon and postmenopausal breast cancers in the Brazilian Unified Health System (SUS) attributable to lack of physical activity. Methods: Population attributable fractions were calculated using prevalence data from 57,962 adults who answered a physical activity questionnaire in the Brazilian National Health Survey, and relative risks of colon and breast cancer from a meta-analysis. Annual costs (1 Int$ = 2.1 reais) with hospitalization, chemotherapy and radiotherapy were obtained from the Hospital and Ambulatory Information Systems of the Brazilian SUS. Two counterfactual scenarios were considered: theoretical minimum risk exposure level (≥8000 MET-min/week) and physical activity guidelines (≥600 MET-min/week). Results: Annually, the Brazilian SUS expended Int$4.5 billion in direct costs related to cancer treatment, of which Int$ 553 million due to colon and breast cancers. Direct costs related to colon and breast cancers attributable to lack of physical activity were Int$23.4 million and Int$ 26.9 million, respectively. Achieving at least the physical activity guidelines would save Int$10.3 mi (colon, Int$ 6.4 mi; breast, Int$3.9 mi). Conclusions: Lack of physical activity accounts for Int$ 50.3 million annually in direct costs related to colon and post-menopausal breast cancers. Population-wide interventions aiming to promote physical activity are needed to reduce the economic burden of cancer in Brazil

Interactive Imitation Learning in Robotics: A Survey

Interactive Imitation Learning (IIL) is a branch of Imitation Learning (IL) where human feedback is provided intermittently during robot execution allowing an online improvement of the robot's behavior. In recent years, IIL has increasingly started to carve out its own space as a promising data-driven alternative for solving complex robotic tasks. The advantages of IIL are its data-efficient, as the human feedback guides the robot directly towards an improved behavior, and its robustness, as the distribution mismatch between the teacher and learner trajectories is minimized by providing feedback directly over the learner's trajectories. Nevertheless, despite the opportunities that IIL presents, its terminology, structure, and applicability are not clear nor unified in the literature, slowing down its development and, therefore, the research of innovative formulations and discoveries. In this article, we attempt to facilitate research in IIL and lower entry barriers for new practitioners by providing a survey of the field that unifies and structures it. In addition, we aim to raise awareness of its potential, what has been accomplished and what are still open research questions. We organize the most relevant works in IIL in terms of human-robot interaction (i.e., types of feedback), interfaces (i.e., means of providing feedback), learning (i.e., models learned from feedback and function approximators), user experience (i.e., human perception about the learning process), applications, and benchmarks. Furthermore, we analyze similarities and differences between IIL and RL, providing a discussion on how the concepts offline, online, off-policy and on-policy learning should be transferred to IIL from the RL literature. We particularly focus on robotic applications in the real world and discuss their implications, limitations, and promising future areas of research

EVENTOS DE PRECIPITAÇÕES EXTREMAS NA AMAZÔNIA OCIDENTAL: RONDÔNIA - BRASIL

Este estudo objetivou analisar a ocorrência de eventos pluviométricos extremos a partir dos dados de precipitação das estações pluviométricas instaladas no estado de Rondônia. Utilizou-se 41 estações pluviométricas com séries históricas acima de 10 anos. Posteriormente tais dados foram analisados pela distribuição de Gumbel, sendo os mesmos relacionados, por meio da desagregação de chuva diária, para períodos de retorno compreendendo 2 a 100 anos e durações pluviométricas de 5 minutos a 24 horas. As séries históricas utilizadas revelaram que a média das chuvas máximas de “um dia”, no estado de Rondônia encontrou-se variando de aproximadamente 71,341 a 173,542 mm/dia, além disso, observou-se que possíveis atuações de fenômenos climáticos como o El Niño e La Niña na região analisada pode ter gerado, respectivamente, as reduções e aumentos na ocorrência de eventos pluviométricos extremos

Análise de chuvas intensas por meio da desagregação de precipitações diárias de Jaru e Machadinho d’Oeste – RO, Brasil

A precipitação pluviométrica, dentre os elementos hidrológicos, é o que mais interfere na vida humana, uma vez que, se configura como a principal entrada de água no sistema hidrológico. Atualmente uma das soluções para realizar a caracterização e estimativa das precipitações intensas é a utilização de curvas Intensidade-Duração-Frequência (IDF), as quais consistem em modelos matemáticos semi-empíricos que preveem a intensidade precipitada por meio da duração e distribuição temporal. Neste contexto, esse estudo objetiva estimar a função IDF para os municípios de Jaru e Machadinho d’Oeste, localizados no estado de Rondônia – Brasil, por meio da metodologia da desagregação de chuvas diárias, que gera séries sintéticas com duração em intervalos menores, por meio de coeficientes que transformam chuva de 24h em outras de menor duração, permitindo assim o desenvolvimento de curvas IDF. As equações geradas apresentaram um coeficiente de ajuste de aproximadamente 96% para o município de Jaru e 92,85% para Machadinho d’Oeste. Por fim, constatou-se que as equações propostas para a estimativa da intensidade das precipitações máximas são de grande aplicabilidade tanto para o município de Machadinho d’Oeste quanto para Jaru

Slit device for FOCCoS, PFS, Subaru

The Fiber Optical Cable and Connector System, FOCCoS, subsystem of the Prime Focus Spectrograph, PFS, for Subaru telescope, is responsible to feed four spectrographs with a set of optical fibers cables. The light injection for each spectrograph is assured by a convex curved slit with a linear array of 616 optical fibers. In this paper we present a design of a slit that ensures the right direction of the fibers by using masks of micro holes. This kind of mask is made by a technique called electroforming, which is able to produce a nickel plate with holes in a linear sequence. The precision error is around 1micron in the diameter and 1 micron in the positions of the holes. This nickel plate may be produced with a thickness between 50 and 200 microns, so it may be very flexible. This flexibility allows the mask to be bent into the shape necessary for a curved slit. The concept requires two masks, which we call Front Mask, and Rear Mask, separated by a gap that defines the thickness of the slit. The pitch and the diameter of the holes define the linear geometry of the slit; the curvature of each mask defines the angular geometry of the slit. Obviously, this assembly must be mounted inside a structure rigid and strong enough to be supported inside the spectrograph. This structure must have a CTE optimized to avoid displacement of the fibers or increased FRD of the fibers when the device is submitted to temperatures around 3 degrees Celsius, the temperature of operation of the spectrograph. We have produced two models. Both are mounted inside a very compact Invar case, and both have their front surfaces covered by a dark composite, to reduce stray light. Furthermore, we have conducted experiments with two different internal structures to minimize effects caused by temperature gradients

QUANTIFICATION OF RESIDUAL CLOVE OIL, BENZOCAINE AND TRICAINE IN FISH FILLETS USING SPE AND UPLC-DAD

Residual quantification of the anesthetics clove oil (CO) – isoeugenol (ISO), eugenol (EUG) and methyleugenol (MET) –,benzocaine (BZN) and tricaine (MS-222) was made in fillets of two fish species: Nile tilapia (Oreochromis niloticus) and acatfish hybrid, cachadia (Pseudoplatystoma reticulatum x Leiarius marmoratus). Samples (n=4) of each fish wereevaluated after submitted to anesthesia in five dosages defined based on the induction time of each species afterdepuration times (0h, 12h, 24h and 48h). Different methodologies of sample preparation were tested and selectedaccording to the better recovery. The quantification of anesthetics was performed by UPLC-DAD. The variance of residualmeans among anesthetics, dosages and fish species was compared. After anesthesia (0h) both species, tilapia andcachadia, presented residual anesthetics. Fishes depurated during 12h, 24h and 48h did not present detectable values, itmeans, values were below the limits of detection. BZN presented the highest mean residual concentration for tilapia andcachadia (p=0.01), while MS-222 presented the lowest residual amounts in tilapias and EUG in cachadias, what may berelated to the metabolism and carcass composition of each fish species. There were no significant differences among thefive dosages, except the lowest MS-222 concentration in tilapias that resulted in higher residual concentrations becauselow dosages increase the induction time and consequently the permanence of the fish in anesthesia. Ultimately, meanvalues of residues in cachadia were higher than in tilapia, and MS-222 and EUG presented the lowest residual values fortilapia and cachadia, respectively