Manifolds with singularities accepting a metric, of positive scalar curvature

We study the question of existence of a Riemannian metric of positive scalar curvature metric on manifolds with the Sullivan-Baas singularities. The manifolds we consider are Spin and simply connected. We prove an analogue of the Gromov-Lawson Conjecture for such manifolds in the case of particular type of singularities. We give an affirmative answer when such manifolds with singularities accept a metric of positive scalar curvature in terms of the index of the Dirac operator valued in the corresponding "K-theories with singularities". The key ideas are based on the construction due to Stolz, some stable homotopy theory, and the index theory for the Dirac operator applied to the manifolds with singularities. As a side-product we compute homotopy types of the corresponding classifying spectra.Comment: Published by Geometry and Topology at http://www.maths.warwick.ac.uk/gt/GTVol5/paper22.abs.htm

On the structure of eigenfunctions corresponding to embedded eigenvalues of locally perturbed periodic graph operators

The article is devoted to the following question. Consider a periodic self-adjoint difference (differential) operator on a graph (quantum graph) G with a co-compact free action of the integer lattice Z^n. It is known that a local perturbation of the operator might embed an eigenvalue into the continuous spectrum (a feature uncommon for periodic elliptic operators of second order). In all known constructions of such examples, the corresponding eigenfunction is compactly supported. One wonders whether this must always be the case. The paper answers this question affirmatively. What is more surprising, one can estimate that the eigenmode must be localized not far away from the perturbation (in a neighborhood of the perturbation's support, the width of the neighborhood determined by the unperturbed operator only). The validity of this result requires the condition of irreducibility of the Fermi (Floquet) surface of the periodic operator, which is expected to be satisfied for instance for periodic Schroedinger operators.Comment: Submitted for publicatio

The population history of northeastern Siberia since the Pleistocene.

Northeastern Siberia has been inhabited by humans for more than 40,000 years but its deep population history remains poorly understood. Here we investigate the late Pleistocene population history of northeastern Siberia through analyses of 34 newly recovered ancient genomes that date to between 31,000 and 600 years ago. We document complex population dynamics during this period, including at least three major migration events: an initial peopling by a previously unknown Palaeolithic population of 'Ancient North Siberians' who are distantly related to early West Eurasian hunter-gatherers; the arrival of East Asian-related peoples, which gave rise to 'Ancient Palaeo-Siberians' who are closely related to contemporary communities from far-northeastern Siberia (such as the Koryaks), as well as Native Americans; and a Holocene migration of other East Asian-related peoples, who we name 'Neo-Siberians', and from whom many contemporary Siberians are descended. Each of these population expansions largely replaced the earlier inhabitants, and ultimately generated the mosaic genetic make-up of contemporary peoples who inhabit a vast area across northern Eurasia and the Americas

Human-robot interaction with pointing gestures: intuitive interaction between co-located humans and robots

Human-robot interaction (HRI) is an active area of research and an essential component for the effective integration of mobile robots in everyday environments. In this PhD work, we studied, designed, implemented, and experimentally validated new efficient interaction modalities between humans and robots that share the same workspace. The core of the work revolves around deictic (pointing) gestures - a skill that humans develop at an early age and use throughout their lives to reference other people, animals, objects, and locations in the surrounding space. To use pointing to control robots, gestures have to be correctly perceived and interpreted by the system. This requires one to model human kinematics and perception, estimate pointed directions and locations using external or wearable sensors, localize robots and humans with respect to each other, and timely provide feedback to let users correct for any inaccuracies in the interaction process. Our main contributions to state of the art lie at the intersection of related topics in psychology, human-robot and human-computer interaction research. In particular, we designed, implemented, and experimentally validated in real-world user studies: - a pointing-based relative localization method and its application to robot identification and engagement; - an approach for pointing-based control of robots on 2D plane and robots freely moving in 3D space; - efficient interaction feedback modalities based on robot motion, lights, and sounds

Demo: Pointing Gestures for Proximity Interaction

We demonstrate a system to control robots in the users proximity with pointing gestures-a natural device that people use all the time to communicate with each other. Our setup consists of a miniature quadrotor Crazyflie 2.0, a wearable inertial measurement unit MetaWearR+ mounted on the user's wrist, and a laptop as the ground control station. The video of this demo is available at https://youtu.be/yafy-HZMk_U [1]

Proximity Human-Robot Interaction Using Pointing Gestures and a Wrist-mounted IMU

We present a system for interaction between co-located humans and mobile robots, which uses pointing gestures sensed by a wrist-mounted IMU. The operator begins by pointing, for a short time, at a moving robot. The system thus simultaneously determines: that the operator wants to interact; the robot they want to interact with; and the relative pose among the two. Then, the system can reconstruct pointed locations in the robot's own reference frame, and provide real-time feedback about them so that the user can adapt to misalignments. We discuss the challenges to be solved to implement such a system and propose practical solutions, including variants for fast flying robots and slow ground robots. We report different experiments with real robots and untrained users, validating the individual components and the system as a whole

Spectrometer Manager: A Versatile Control Software for Pulse EPR Spectrometers

ABSTRACT: A versatile control software for pulse EPR spectrometers is introduced. Common and task-specific problems are discussed and their solutions are described. The software provides the full spectrum of possibilities needed to perform arbitrary multidimensional pulse experiments. It allows for an easy interfacing of commonly used hardware components and enables straightforward modifications of the spectrometer. Good performance, configurability, and a number of unique features turn this software into an excellen