Intrinsic Motivation and Mental Replay enable Efficient Online Adaptation in Stochastic Recurrent Networks

Autonomous robots need to interact with unknown, unstructured and changing environments, constantly facing novel challenges. Therefore, continuous online adaptation for lifelong-learning and the need of sample-efficient mechanisms to adapt to changes in the environment, the constraints, the tasks, or the robot itself are crucial. In this work, we propose a novel framework for probabilistic online motion planning with online adaptation based on a bio-inspired stochastic recurrent neural network. By using learning signals which mimic the intrinsic motivation signalcognitive dissonance in addition with a mental replay strategy to intensify experiences, the stochastic recurrent network can learn from few physical interactions and adapts to novel environments in seconds. We evaluate our online planning and adaptation framework on an anthropomorphic KUKA LWR arm. The rapid online adaptation is shown by learning unknown workspace constraints sample-efficiently from few physical interactions while following given way points.Comment: accepted in Neural Network

The Feasibility of Reclaiming Shell Material from Investment Casting

This report examines the feasibility of investment shell component reclamation. Shell material components and their compositions are investigated with an industry survey, a study of the available literature, and analysis of specimen shell materials. physical properties and factors related to the reclamation and reuse of shell materials are described. Well known mineral processing methods are capable of producing concentrates of the various shell components. The theory and techniques of some applicable processes are discussed to assist with the development of reclamation operations. The recommended methods are; comminution by roll crushing, component concentration by screening, gravity settling or heavy medium separation. Aluminosilicate stucco (a major component of many investment shells) can be recovered in a form suitable for reuse as backup stucco. Zircon (a minor component in many shell compositions) -can be concentrated in an impure form, and subsequent caustic liberation treatments can remove the intermixed silica phases. Reuse of such zircon in investment casting may be possible but will require careful qualification testing. Fused and crystalline silica (major components of most shell compositions) are not reusable for investment casting. The feasibility of reclamation will be influenced by individual foundry choices of materials, composition and shell practice.HWRIC Project No. RRT-10NTIS PB92-16219

Ligand design for site-selective installation of Pd and Pt centers to generate homo- and heteropolymetallic motifs

The modular synthesis of a series of nitrogen-rich polydentate ligands that feature a common pincer-type framework is reported. These ligands allow for site-selective installation of palladium and platinum to give rise to bi- and trimetallic complexes that have d^(8)–d^(8) interactions

Attitude determination for small satellites using gps signal-to-noise ratio

Thesis (M.S.) University of Alaska Fairbanks, 2014An embedded system for GPS-based attitude determination (AD) using signal-to-noise (SNR) measurements was developed for CubeSat applications. The design serves as an evaluation testbed for conducting ground based experiments using various computational methods and antenna types to determine the optimum AD accuracy. Raw GPS data is also stored to non-volatile memory for downloading and post analysis. Two low-power microcontrollers are used for processing and to display information on a graphic screen for real-time performance evaluations. A new parallel inter-processor communication protocol was developed that is faster and uses less power than existing standard protocols. A shorted annular patch (SAP) antenna was fabricated for the initial ground-based AD experiments with the testbed. Static AD estimations with RMS errors in the range of 2.5° to 4.8° were achieved over a range of off-zenith attitudes

Formation of Polymer Micro-Tubes

Abstract Current demand for organs is greater than the supply of donated organs, which means that a new method of obtaining replacement organs needs to be found. The objective of the research is to evaluate the use of thermo-triggered self-rolling polymer tubes that can be used for scaffolds in tissue engineering. Additionally, the research also includes a method for forming polymer tubes through the removal of a sugar fiber, coated with a thin film of polymer, by dissolving it in deionized water. For the first approach, the effect of the aqueous environment and temperature on a polymer bilayer was observed in this research. In particular, the effect of the aqueous environment on the self-rolling ability of the polymer bilayer. Also, the effect of temperature on the swelling of the active gelatin layer. The active gelatin layer had a thickness of 577 nanometers and the passive polystyrene layer had a thickness of 275 nanometers. It was observed that with increased temperature the tube would begin to roll from end to end but, would not form a complete tube. For the second approach, hollow polymer tubes with diameters on a micrometer scale were easily produced. The self-rolling polymer micro-tubes were unsuccessful, simpler methods of polymer tube formation should be further sought to encapsulating cells for tissue engineering

ASSESSING SOCIAL MEDIA HABITS FOR WORSENING SYMPTOMS OF DEPRESSION

This project was created to assist providers working in the mental health field in treating patients with major depressive disorder (MDD) by assessing for problematic social media use (PSMU), which may exacerbate symptoms of depression. A Likert scale style questionnaire, which was accessible online for clinicians, was developed and used to assess psychiatric patients between the ages of 18-35 with a diagnosis of depression using specific questions about the patient’s social media use, which research regards as having the potential to worsen depressive symptoms. This survey helped determine if PSMU may be considered as an area for assessment in patients with depression based on data collected, as well as patient and clinician feedback. Education about PSMU and strategies for modifying use was included based on current research recommendations. A pre-and post-intervention depression screening was completed by each participant to determine, individually, if depressive symptoms showed improvement at a two-month follow-up

On the Complexity of Reconstructing Chemical Reaction Networks

The analysis of the structure of chemical reaction networks is crucial for a better understanding of chemical processes. Such networks are well described as hypergraphs. However, due to the available methods, analyses regarding network properties are typically made on standard graphs derived from the full hypergraph description, e.g.\ on the so-called species and reaction graphs. However, a reconstruction of the underlying hypergraph from these graphs is not necessarily unique. In this paper, we address the problem of reconstructing a hypergraph from its species and reaction graph and show NP-completeness of the problem in its Boolean formulation. Furthermore we study the problem empirically on random and real world instances in order to investigate its computational limits in practice