Stability and Transparency Analysis of a Teleoperation Chain For Microscale Interaction.

International audienceMicroscale teleoperation with haptic feedback requires scaling gains in the order of 104 107. These high gains impose a trade-off between stability and transparency. Due to the conservative approach used in most designs, transparency is reduced since damping is added to the system to guarantee stability. Starting from the fact that series, negative feedback and parallel connection of passive systems is a passive system, a new approach is addressed in this work. We propose here a complete teleoperation chain designed from the ground up for full transparency and stability, including a novel self-sensing probe and a high fidelity force-feedback haptic interface. By guaranteeing the passivity of each device and assuming that the human operator and the environment are passive systems, a homothetic direct coupling can be used without jeopardizing the stability and provides best transparency. The system is experimentally demonstrated in the complex case of a probe interacting with a water droplet under human control, while accurately transcribing the interaction back to operator

Voltage stability analysis of load buses in electric power system using adaptive neuro-fuzzy inference system (anfis) and probabilistic neural network (pnn)

This paper presents the application of neural networks for analysing voltage stability of load buses in electric power system. Voltage stability margin (VSM) and load power margin (LPM) are used as the indicators for analysing voltage stability. The neural networks used in this research are divided into two types. The first type is using the neural network to predict the values of VSM and LPM. Multilayer perceptron back propagation (MLPBP) neural network and adaptive neuro-fuzzy inference system (ANFIS) will be used. The second type is to classify the values of VSM and LPM using the probabilistic neural network (PNN). The IEEE 30-bus system has been chosen as the reference electrical power system. All of the neural network-based models used in this research is developed using MATLAB

Water and Nutrition: Harmonizing actions for the United Nations Decade of Action on Nutrition and the United Nations Water Action Decade

Progress for both SDG 2 and SDG 6 has been unsatisfactory, with several indicators worsening over time, including an increase in the number of undernourished, overweight and obese people, as well as rapid increases in the number of people at risk of severe water shortages. This lack of progress is exacerbated by climate change and growing regional and global inequities in food and water security, including access to good quality diets, leading to increased violation of the human rights to water and food. Reversing these trends will require a much greater effort on the part of water, food security, and nutrition communities, including stronger performances by the United Nations Decade of Action on Nutrition and the United Nations International Decade for Action on Water for Sustainable Development. To date, increased collaboration by these two landmark initiatives is lacking, as neither work program has systematically explored linkages or possibilities for joint interventions. Collaboration is especially imperative given the fundamental challenges that characterize the promotion of one priority over another. Without coordination across the water, food security, and nutrition communities, actions toward achieving SDG2 on zero hunger may contribute to further degradation of the world’s water resources and as such, further derail achievement of the UN Decade of Action on Water and SDG 6 on water and sanitation. Conversely, actions to enhance SDG 6 may well reduce progress on the UN Decade of Action on Nutrition and SDG 2. This paper reviews these challenges as part of a broader analysis of the complex web of pathways that link water, food security and nutrition outcomes. Climate change and the growing demand for water resources are also considered, given their central role in shaping future water and nutrition security. The main conclusions are presented as three recommendations focused on potential avenues to deal with the complexity of the water-nutrition nexus, and to optimize outcomes

Effects of Impedance Reduction of a Robot for Wrist Rehabilitation on Human Motor Strategies in Healthy Subjects during Pointing Tasks

Studies on human motor control demonstrated the existence of simplifying strategies (namely `Donders' law') adopted to deal with kinematically redundant motor tasks. In recent research we showed that Donders' law also holds for human wrist during pointing tasks, and that it is heavily perturbed when interacting with a highly back-drivable state-of-the-art rehabilitation robot. We hypothesized that this depends on the excessive mechanical impedance of the Pronation/Supination (PS) joint of the robot and in this work we analyzed the effects of its reduction. To this end we deployed a basic force control scheme, which minimizes human-robot interaction force. This resulted in a 70% reduction of the inertia in PS joint and in decrease of 81% and 78% of the interaction torques during 1-DOF and 3-DOFs tasks. To assess the effects on human motor strategies, pointing tasks were performed by three subjects with a lightweight handheld device, interacting with the robot using its standard PD control (setting impedance to zero) and with the force-controlled robot. We quantified Donders' law as 2-dimensional surfaces in the 3-dimensional configuration space of rotations. Results revealed that the subject-specific features of Donders' surfaces reappeared after the reduction of robot impedance obtained via the force control

Mutations in DYNC2LI1 disrupt cilia function and cause short rib polydactyly syndrome.

The short rib polydactyly syndromes (SRPSs) are a heterogeneous group of autosomal recessive, perinatal lethal skeletal disorders characterized primarily by short, horizontal ribs, short limbs and polydactyly. Mutations in several genes affecting intraflagellar transport (IFT) cause SRPS but they do not account for all cases. Here we identify an additional SRPS gene and further unravel the functional basis for IFT. We perform whole-exome sequencing and identify mutations in a new disease-producing gene, cytoplasmic dynein-2 light intermediate chain 1, DYNC2LI1, segregating with disease in three families. Using primary fibroblasts, we show that DYNC2LI1 is essential for dynein-2 complex stability and that mutations in DYNC2LI1 result in variable length, including hyperelongated, cilia, Hedgehog pathway impairment and ciliary IFT accumulations. The findings in this study expand our understanding of SRPS locus heterogeneity and demonstrate the importance of DYNC2LI1 in dynein-2 complex stability, cilium function, Hedgehog regulation and skeletogenesis

Use of bioremediation for the removal of petroleum hydrocarbons from the soil: an overview

Large amount of organic and inorganic compounds are released constantly in the environment as a consequence of human activity and technological and industrial advancement. Environmental pollution by petroleum and petrochemicals, such as petroleum hydrocarbons (PHCs), is considered one of the most serious hazards today due to its worldwide distribution. Contamination by these pollutants causes degradation of global environment and a substantial reduction in biodiversity. In addition, a deep removal of the pollutants is often required to prevent their migration into the water, air and therefore threaten human health. In this way, the search for ecologically sustainable approaches to repair contaminated environments have been of great concern in society. Bioremediation is a technique, based on the metabolic activity of living organisms, which aims to reduce, degrade and/or remove contaminants from the marine and terrestrial ecosystems. It is a more economical and more efficient process to minimize waste, compared to the usual physical-chemical treatment methods. Historically, bioremediation has been used to restore environments polluted by PHCs, where microbial communities play a key role during this course, either by the direct degradation of pollutants or by interaction with other microorganisms. Finally, this review discusses about the soil contamination by PHCs, the role of living organisms in this mechanism and their recent application in bioremediation process

Human performance measuring device

Complex coordinator, consisting of operator control console, recorder, subject display panel, and limb controls, measures human performance by testing perceptual and motor skills. Device measures psychophysiological functions in drug and environmental studies, and is applicable to early detection of psychophysiological body changes