From virtual demonstration to real-world manipulation using LSTM and MDN

Robots assisting the disabled or elderly must perform complex manipulation tasks and must adapt to the home environment and preferences of their user. Learning from demonstration is a promising choice, that would allow the non-technical user to teach the robot different tasks. However, collecting demonstrations in the home environment of a disabled user is time consuming, disruptive to the comfort of the user, and presents safety challenges. It would be desirable to perform the demonstrations in a virtual environment. In this paper we describe a solution to the challenging problem of behavior transfer from virtual demonstration to a physical robot. The virtual demonstrations are used to train a deep neural network based controller, which is using a Long Short Term Memory (LSTM) recurrent neural network to generate trajectories. The training process uses a Mixture Density Network (MDN) to calculate an error signal suitable for the multimodal nature of demonstrations. The controller learned in the virtual environment is transferred to a physical robot (a Rethink Robotics Baxter). An off-the-shelf vision component is used to substitute for geometric knowledge available in the simulation and an inverse kinematics module is used to allow the Baxter to enact the trajectory. Our experimental studies validate the three contributions of the paper: (1) the controller learned from virtual demonstrations can be used to successfully perform the manipulation tasks on a physical robot, (2) the LSTM+MDN architectural choice outperforms other choices, such as the use of feedforward networks and mean-squared error based training signals and (3) allowing imperfect demonstrations in the training set also allows the controller to learn how to correct its manipulation mistakes

Synchronization in Networks of Identical Systems via Pinning: Application to Distributed Secondary Control of Microgrids

Motivated by the need for fast synchronized operation of power microgrids, we analyze the problem of single and multiple pinning in networked systems. We derive lower and upper bounds on the algebraic connectivity of the network with respect to the reference signal. These bounds are utilized to devise a suboptimal algorithm with polynomial complexity to find a suitable set of nodes to pin the network effectively and efficiently. The results are applied to secondary voltage pinning control design for a microgrid in islanded operation mode. Comparisons with existing single and multiple pinning strategies clearly demonstrates the efficacy of the obtained results.Comment: 11 pages, 9 figures, submitted to Transactions on Control Systems Technolog

Maternal anaemia and its effects on neonatal anthropometric parameters in patients attending a tertiary care institute of Solan, Himachal Pradesh, India

Background: Anaemia during pregnancy is a significant concern in India. The consequences of iron deficiency anaemia during pregnancy are often serious and long lasting for both the mother and the foetus. Haematocrit measurement is an acceptable and recommended method for anaemia determination especially in situations where limited resources are available, and the technical support is poor. There is a rough conversion factor of 3 which converts the HCT value to approximate haemoglobin level. Present study desires to know the prevalence of anaemia (with classification into mild, moderate and severe) in 3rd trimester pregnancy, to know effect of anaemia in pregnancy on new-born anthropometric parameters and to assess the validity of the threefold conversion between haemoglobin and haematocrit for the determination of anaemia in pregnancy.Methods: The estimation of haematocrit was done by micro-haematocrit method and estimation of haemoglobin was done by automated blood cell analyzer based on cyanmethemoglobin method. Welch's ANOVA, Post Hoc games Howell test and Bland Altman limits of agreement method were used for statistical analysis.Results: Present study showed that 53.75% women in their 3rd trimester were anaemic (mild, moderate and severe anaemic mothers were 22.25%, 28.25% and 3.25% respectively). The standard 3-fold conversion between the haemoglobin and haematocrit was not found to be valid for the assessment of anaemia in the 3rd trimester pregnancy. Finally, while comparing anthropometric measurements between mild/ no anaemia group with severe anaemia group we found that all measurements were less in severe anaemia group and this difference was statistically significant.Conclusions: This study shows that 53.75% women in their 3rd trimester were anaemic, which closely mimic the WHO data but is about 11% more than the prevalence in Himachal Pradesh. Secondly, the standard 3-fold conversion between the haemoglobin and haematocrit was not found to be valid for the assessment of anaemia in the 3rd trimester pregnancy. Finally, birth weight, height, head circumference, chest circumference and mid-arm circumference were significantly affected by third trimester haemoglobin that too the most in severe anaemia cases

The Family Storyteller: A Collaborative Family Literacy Program

Children who begin school with limited literacy skills are struggling uphill from the first day they set foot in school. The University of Nevada Cooperative Extension initiated a collaborative family literacy effort to improve the literacy skills of both parents and their children. A series of six weekly workshops have been provided across Nevada to over 500 families. Pre-post interviews with families have revealed significant increases in the amount of time parents read with their children, their enjoyment of reading time, and their use of specific parent reading techniques. Children have made significant gains in their enjoyment of reading with parents and their understanding of print concepts

Marginalization: a narrative of the Adivasi community in Assam

"This paper is about north east India, a region that has emerged through a difficult journey of struggles, conflicts, acrimony, with little support from the Centre and a population that kept to itself, holding its affinity to its own land-based practices and cultural norms...This paper will factor the lives of Adivasis, particularly the women, who lived andstill live lives of deprivation, discrimination (both within their community as well as the state)and extreme vulnerabilities. It is the story of marginalization.

Comparison of Adaptive Control Architectures for Flutter Suppression

A study is conducted to derive and implement a state feedback model reference adaptive control (MRAC) solutions for a 2-D aeroelastic nonlinear system and in evaluating the robustness of different control strategies to damage leading to the deterioration of the structural stiffness characteristics. The standard MRAC, a modified MRAC and the adaptive controller are the three model reference adaptive control solutions analyzed. The standard direct MRAC solution serves as the threshold to assess whether or not the more complex algorithms are an effective improvement to it