The A-CLASS Method for Autonomous Quadcopter Formation Control

Methodologies aimed at Advanced Control through Learning in Autonomous Swarm Systems (A-CLASS) utilize the tools of nonlinear control to develop and rigorously analyze new strategies of machine learning for formation control in collaborative autonomous multi-agent UAV groups. In A-CLASS, new algorithms for online, real-time machine learning can be achieved through the investigation of new automatic control policy improvement strategies, which optimize future control actions based on past experience. Recent advances in reinforcement learning methods have made significant progress in understanding and mimicking brain functionality at the level of the brainstem, basal ganglia, cerebellum, and cerebral cortex. In particular, neural network (NN)-based actor-critic structures, which utilize approximate dynamic programming (ADP), are promising techniques for simulating brain-like thinking in engineering systems. In this research project, new experience replay-based multi-agent control techniques will be investigated, which ‘learn’ from experience in real time the optimal control action in response to a given sensor stimulus. The end goal of this research project is experimental demonstration of new A-CLASS-based control methods on multi-agent groups of autonomous quadcopter UAVs using a motion capture arena

Static splay-stripes in a hybrid aligned nematic layer

A usual aperiodic hybrid alignment can appear in a nematic layer with weak anchoring only if the cell thickness is greater than a critical value dh, below which a static periodic pattern instead of the hybrid aperiodic structure could be preferred, if the energy cost for a three dimensional deformation, involving twist, is less than the cost for the two-dimensional deformation of splay-bend type. We have studied the occurrence of the mechanical instability leading to the static periodic splay-stripes, i. e. in the case of the tilt anchoring stronger at the one of the walls, in which the anchoring is planar, for several values of the twist anchoring strengths. Here the behavior of the threshold d for the periodic stripes is presented and discussed as a function of the anchoring energies and of the ratio of nematic bulk elastic constants, in the frame of the usual continuum theory

Automated Standard Hazard Tool

The current system used to generate standard hazard reports is considered cumbersome and iterative. This study defines a structure for this system's process in a clear, algorithmic way so that standard hazard reports and basic hazard analysis may be completed using a centralized, web-based computer application. To accomplish this task, a test server is used to host a prototype of the tool during development. The prototype is configured to easily integrate into NASA's current server systems with minimal alteration. Additionally, the tool is easily updated and provides NASA with a system that may grow to accommodate future requirements and possibly, different applications. Results of this project's success are outlined in positive, subjective reviews complete by payload providers and NASA Safety and Mission Assurance personnel. Ideally, this prototype will increase interest in the concept of standard hazard automation and lead to the full-scale production of a user-ready application

Quadrotor Swarm Arena (QuaSAr) Development of a Swarm Control Testbed

Swarm control systems are increasingly popular in the robotics industry and academia due to their many potential applications. The goal of the Quadrotor Swarm Arena (QuaSAr) project is to construct a quadrotor swarm control testbed to provide researchers with the tools needed to experimentally investigate this emerging science. This testbed is equipped with a motion capture system, test control station, and numerous quadrotor UAVs. MATLAB-Simulink is utilized for control law development, data processing, and test control. This configuration allows researchers to test developing control law in a \u27plug and play\u27 manner as control development and test control are all completed using the same tools. Thus, the QuaSAr testbed an increasingly valuable tool to a wide set of researchers. Currently, the testbed is undergoing final testing and initial operation. Improved single-agent control methods are continuously being developed and initial swarm control research is underway. The combination of the completed and future work has promising implications for the continued success of the QuaSAr project

Atomic Quantum Simulation of U(N) and SU(N) Non-Abelian Lattice Gauge Theories

Using ultracold alkaline-earth atoms in optical lattices, we construct a quantum simulator for U(N) and SU(N) lattice gauge theories with fermionic matter based on quantum link models. These systems share qualitative features with QCD, including chiral symmetry breaking and restoration at non-zero temperature or baryon density. Unlike classical simulations, a quantum simulator does not suffer from sign problems and can address the corresponding chiral dynamics in real time.Comment: 12 pages, 5 figures. Main text plus one basic introduction to the topic and one supplementary material on implementation. Final versio

SO(3) "Nuclear Physics" with ultracold Gases

An ab initio calculation of nuclear physics from Quantum Chromodynamics (QCD), the fundamental SU(3) gauge theory of the strong interaction, remains an outstanding challenge. Here, we discuss the emergence of key elements of nuclear physics using an SO(3) lattice gauge theory as a toy model for QCD. We show that this model is accessible to state-of-the-art quantum simulation experiments with ultracold atoms in an optical lattice. First, we demonstrate that our model shares characteristic many-body features with QCD, such as the spontaneous breakdown of chiral symmetry, its restoration at finite baryon density, as well as the existence of few-body bound states. Then we show that in the one-dimensional case, the dynamics in the gauge invariant sector can be encoded as a spin S=3/2 Heisenberg model, i.e., as quantum magnetism, which has a natural realization with bosonic mixtures in optical lattices, and thus sheds light on the connection between non-Abelian gauge theories and quantum magnetism.Comment: 34 pages, 9 figure

"In parents' school experience, the teacher was just lecturing at the front": school-family partnerships in schools with personalized learning concepts

Our study examines communication and cooperation between schools that have implemented personalized learning concepts and the families of their students. The study forms part of a longitudinal mixed-methods research project (2012–2015, supported by the foundation Mercator Switzerland). Conducting a qualitative content analysis of interviews and strategic documents (N = 12 schools), we developed an analytic instrument, applying a semi-deductive procedure. It is based on research on school-family partnerships and consists of five communication and cooperation structures (a) channels of two-way information exchange and cooperation; b) information flow from schools to parents; c) parent events; d) parent volunteering; e) parent involvement in decision-making) and five content and object areas i) psychological, pedagogical, and school concepts; ii) understanding families; iii) learning and instruction; iv) learning progress and achievement; v) problems, conflicts). The linkage between the structures and the content of the interactions led to three paradigmatic types of schools. Type 1: Informal communication and cooperation; Type 2: Reactive communication and cooperation; Type 3: Strategic communication and cooperation. The results indicate that it can be particularly advantageous to center the communication on student progress, to focus parent events on education-related topics, and to give the parents a voice in decision-making processes

Quadrotor Swarm Arena

Unmanned Aerial Vehicle (UAV) swarm control platforms have many applications in rescue, commercial, and government fields. The goal of this ongoing project is to construct a space solely dedicated to investigating this important discipline through the control of quadrotor clusters (groups of quadrotor UAVs). This space is equipped with a motion capture system, test control station, and numerous quadrotor UAVs. The test control station utilizes MATLAB-Simulink for data management and control law development. A significant benefit to this construction is its seamless ability to test researchers\u27 control law in a \u27plug and play\u27 manner, as Simulink is widely used in the controls community. To date, the testbed includes a vehicle enclosure, multiple quadrotor agents, the motion capture system, and a ground station. Current and future work includes the final integration of these components and experimental data collection

Larval Length Measurement as an Alternative to Weight as an Indicator of Growth in the Seven-Day Fathead Minnow Larval Survival and Growth Test

Linear regression analyses were performed on weights and lengths of larval fathead minnows in an attempt to evaluate these variables as comparable measures of the growth endpoint in short-term chronic assays. Mean dry weight and mean individual total lengths were highly and positively correlated (R values of 0.82 - 0.98) for data generated from seven-day fathead minnow larval survival and growth tests performed on effluents from a variety of treatment facilities (industrial, municipal, and refinery). Length measurements were also found to be accurate, precise, and capable of detecting the same level of significant differences between control and treatment means. In comparison to weight measurements, substantial time can be saved using larval lengths obtained with a very simple setup and cost of equipment can be reduced as well. Length measurements should be considered as an alternative to the mean dry weights presently required by EPA Method 1000.0.Natural Scienc