Wireless Interference Identification with Convolutional Neural Networks

The steadily growing use of license-free frequency bands requires reliable coexistence management for deterministic medium utilization. For interference mitigation, proper wireless interference identification (WII) is essential. In this work we propose the first WII approach based upon deep convolutional neural networks (CNNs). The CNN naively learns its features through self-optimization during an extensive data-driven GPU-based training process. We propose a CNN example which is based upon sensing snapshots with a limited duration of 12.8 {\mu}s and an acquisition bandwidth of 10 MHz. The CNN differs between 15 classes. They represent packet transmissions of IEEE 802.11 b/g, IEEE 802.15.4 and IEEE 802.15.1 with overlapping frequency channels within the 2.4 GHz ISM band. We show that the CNN outperforms state-of-the-art WII approaches and has a classification accuracy greater than 95% for signal-to-noise ratio of at least -5 dB

Sistema de localização para hospitais com base em tempo de propagação

Mestrado em Engenharia de Computadores e TelemáticaO presente trabalho discute a localiza ção de pacientes em ambientes hospitalares e contêm as seguintes partes principais: em primeiro lugar, e introduzido o estado de arte sobre t écnicas de localiza ção de modo a fornecer ao leitor os conhecimentos básicos para os capítulos seguintes. Em segundo lugar, e efectuada uma avaliação do estado de arte tendo em conta os requisitos necessários para ambientes hospitalares. Em terceiro lugar, e especifi cado um sistema de localiza ção de pacientes com enfoque na sua arquitectura. A quarta e ultima parte cont em uma proposta de implementação de um sistema de localização, fazendo referencia a investiga ção actual, sendo tamb ém descrito o software do servidor de localiza ção que foi desenvolvido durante a tese.The present work discusses the localisation of patients in hospital environments and contains following main parts: Firstly, the state-of-the-art localisation techniques are introduced to provide the reader with the basic knowledge the following chapters are based on. Secondly, the state-of-the-art is evaluated regarding the requirements for a use in hospital environments. Thirdly, a blueprint design for a hospital patient localisation system, providing the key functionalities without looking at a speci c implementation, is developed. The fourth and last part contains the proposal of a speci c localisation system implementation by referencing to existing research and development as well as the introduction of a localisation server software that has been developed during the thesis

A portable laser system for high precision atom interferometry experiments

We present a modular rack-mounted laser system for the cooling and manipulation of neutral rubidium atoms which has been developed for a portable gravimeter based on atom interferometry that will be capable of performing high precision gravity measurements directly at sites of geophysical interest. This laser system is constructed in a compact and mobile design so that it can be transported to different locations, yet it still offers improvements over many conventional laboratory-based laser systems. Our system is contained in a standard 19" rack and emits light at five different frequencies simultaneously on up to 12 fibre ports at a total output power of 800 mW. These frequencies can be changed and switched between ports in less than a microsecond. The setup includes two phase-locked diode lasers with a phase noise spectral density of less than 1 \mu rad/sqrt(Hz) in the frequency range in which our gravimeter is most sensitive to noise. We characterize this laser system and evaluate the performance limits it imposes on an interferometer.Comment: 8 pages, 11 figures; The final publication is available at http://www.springerlink.co

The structure of academic self-concept. A methodological review and empirical illustration of central models

The structure of academic self-concept (ASC) is assumed to be multidimensional and hierarchical. This methodological review considers the most central models depicting the structure of ASC: a higher-order factor model, the Marsh/Shavelson model, the nested Marsh/Shavelson model, a bifactor representation based on exploratory structural equation modeling, and a first-order factor model. We elaborate on how these models represent the theoretical assumptions on the structure of ASC and outline their inherent psychometric properties. We analyzed these models using a data set of German 10th-grade students (N = 1,232) including a wide range of domain-specific ASCs as well as general ASC. The correlations among ASCs and between ASCs and academic achievement varied depending on the structural model used. We conclude with discussing recommendations for research purposes and advantages and limitations of each ASC model. Our approach may also guide research on other affective or motivational constructs (e.g., academic anxiety or interest). (DIPF/Orig.

Photonic candle – focusing light using nano-bore optical fibers

Focusing light represents one of the fundamental optical functionalities that is used in a countless number of situations. Here we introduce the concept of nano-bore optical fiber mediated light focusing that allows to efficiently focus light at micrometer distance from the fiber end face. Since the focusing effect is provided by the fundamental fiber mode, device implementation is extremely straightforward since no post-processing or nano-structuring is necessary. Far-field measurements on implemented fibers, simulations, and a dual-Gaussian beam toy model confirm the validity of the concept. Due to its unique properties such as strong light localization, a close to 100% implementation success rate, extremely high reproducibility, and its compatibility with current fiber circuitry, the concept will find application in numerous areas that demand to focus at remote distances

The Evolution of Complex Muscle Cell In Vitro Models to Study Pathomechanisms and Drug Development of Neuromuscular Disease

Many neuromuscular disease entities possess a significant disease burden and therapeutic options remain limited. Innovative human preclinical models may help to uncover relevant disease mechanisms and enhance the translation of therapeutic findings to strengthen neuromuscular disease precision medicine. By concentrating on idiopathic inflammatory muscle disorders, we summarize the recent evolution of the novel in vitro models to study disease mechanisms and therapeutic strategies. A particular focus is laid on the integration and simulation of multicellular interactions of muscle tissue in disease phenotypes in vitro. Finally, the requirements of a neuromuscular disease drug development workflow are discussed with a particular emphasis on cell sources, co-culture systems (including organoids), functionality, and throughput.Peer Reviewe

Ultralong Tracking of Fast‐Diffusing Nano‐Objects inside Nanofluidic Channel−Enhanced Microstructured Optical Fiber

Nanoparticle tracking analysis (NTA) represents one essential technology to characterize diffusing nanoscale objects. Herein, uncovering dynamic processes and high-precision measurements requires tracks with thousands of frames to reach high statistical significance, ideally at high frame rates. Optical fibers with nanochannels are used for NTA, successfully demonstrating acquisition of trajectories of fast diffusion nano-objects with 100 000 frames. Due to the spatial limitation of the central nanofluidic channel, diffusion of objects illuminated by the core mode is confined, enabling the recording of Brownian motion over extraordinarily long time scales at high frame rates. The resulting benefits are discussed on a representative track of a gold nanosphere diffusing in water in over nearly 100 000 frames at 2 kHz frame rate. In addition to the verification of the fiber-based NTA using two data processing methods, a segmented analysis reveals a correlation between precision of determined diameter and continuous time interval (i.e., number of frames per subtrajectory). The presented results demonstrate the capabilities of fiber-based NTA in terms of 1) determining diameters with extraordinary high precision of single species and 2) monitoring dynamic processes of the object or the fluidic environment, both of which are relevant within biology, microrheology, and nano-object characterization

Ultrafast dynamics in monolayer TMDCs: the interplay of dark excitons, phonons and intervalley Coulomb exchange

Understanding the ultrafast coupling and relaxation mechanisms between valleys in transition metal dichalcogenide semiconductors is of crucial interest for future valleytronic devices. Recent ultrafast pump-probe experiments showed an unintuitive significant bleaching at the excitonic $B$ transition after optical excitation of the energetically lower excitonic $A$ transition. Here, we present a possible microscopic explanation for this surprising effect. It is based on the joint action of exchange coupling and phonon-mediated thermalization into dark exciton states and does not involve a population of the B exciton. Our work demonstrates how intra- and intervalley coupling on a femtosecond timescale governs the optical valley response of 2D semiconductors