Low-effort place recognition with WiFi fingerprints using deep learning

Using WiFi signals for indoor localization is the main localization modality of the existing personal indoor localization systems operating on mobile devices. WiFi fingerprinting is also used for mobile robots, as WiFi signals are usually available indoors and can provide rough initial position estimate or can be used together with other positioning systems. Currently, the best solutions rely on filtering, manual data analysis, and time-consuming parameter tuning to achieve reliable and accurate localization. In this work, we propose to use deep neural networks to significantly lower the work-force burden of the localization system design, while still achieving satisfactory results. Assuming the state-of-the-art hierarchical approach, we employ the DNN system for building/floor classification. We show that stacked autoencoders allow to efficiently reduce the feature space in order to achieve robust and precise classification. The proposed architecture is verified on the publicly available UJIIndoorLoc dataset and the results are compared with other solutions

Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_B > 500 MeV), effects of chiral symmetry, and the equation-of-state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2022, in the context of the worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal

Testing and selection of electrical actuators for multi-rotor flying robot

Artykuł omawia metody doboru elementów składających się na jednostkę napędową wielowirnikowego robota latającego. Przedstawiono wymagania, jakie powinny spełniać badane jednostki napędowe. Praca zawiera przykładowe wyniki testów przeprowadzonych na hamowni oraz wyciągnięte na ich podstawie wnioski. Przeprowadzone badania pokazują, że nie jest konieczna budowa dedykowanych regulatorów obrotów, czy też modyfikowanie gotowych układów, by mogły być one stosowane jako napęd do wielowirnikowych robotów latających. Na podstawie przeprowadzonych testów zaobserwowano, że pomimo zastosowania zestawów składających się z identycznych elementów, otrzymane charakterystyki znacząco się różnią. Prowadzi to do trudności w stabilizacji robota podczas lotu, a także skraca jego czas pracy.This paper discusses selection criteria and assumptions for multi-rotor flying robot actuators. Results of tests for units made of electrical (high rpm) motors, propellers and rotation speed governors are presented in Section 2 (Fig. 1). Driving units were selected by three tests (Section 4). The first one allowed specifying the maximum thrust of a tested driving unit (Fig. 5). The second test simulated the work of a driving unit during stabilizing movements of the flying platform (Fig. 6). The purpose was to determine the quadrocopter reaction rate to changes in the control signal. The third test was related to simulating tilting of the platform while maneuvering (Fig. 7). In another series of tests the frequency of the pulse speed governor was increased from 45 to 400 Hz (Fig. 8). The conclusions are based on the tests results. The general one is that the typical governors can be used in multi-rotor UAV without particular modifications and there is no need to design customized governors. However, it was observed that driving units made of elements having identical nominal parameters, had quite different regulatory characteristics (Fig. 10). Due to it, stabilization was more difficult and, at the same time, the power consumption increased. The experiments were conducted with a dedicated measurement system (Fig. 4, Section 3). The representative number of motors, propellers and rotation speed governors was tested and compared in order to select the optimal driving unit, satisfying the initial assumptions and criteria

Wstępne badania trójokularowej głowicy wizyjnej do prac podwodnych

This paper describes the basic idea of operation and assumptions of the Trinocular Vision System (TVS) designed to support the underwater exploration with the use of the autonomous vehicle. The paper characterizes the optical proper-ties of the inland water environment, and the process of the image formation in that environment. The paper presents the aim of the image fusion and also the design process of a multimodal vision system, i.e. the selection of its components confirmed by prior research in the context of underwater operation.Artykuł przedstawia podstawowe założenia odnośnie działania trójokularowej głowicy wizyjnej (TVS) zaprojektowanej i wykonanej do rejestracji obrazów w wodach śródlądowych przy wykorzystaniu autonomicznego pojazdu podwodnego. Opisane zostało środowisko operacyjne takiej głowicy, jakim są wody śródlądowe oraz proces powstawania informacji wizyjnej, w tym właśnie środowisku. Następnie wyjaśnione zostało pojęcie i cel fuzji obrazowej oraz proces projektowania głowicy, tj. dobór elementów optycznych i mechanicznych poparty wcześniejszymi badaniami w zadanych pasmach promieniowania

Comparison of supervised learning methods for spike time coding in spiking neural networks

In this review we focus our attention on supervised learning methods for spike time coding in Spiking Neural Networks (SNNs). This study is motivated by recent experimental results regarding information coding in biological neural systems, which suggest that precise timing of individual spikes may be essential for efficient computation in the brain. We are concerned with the fundamental question: What paradigms of neural temporal coding can be implemented with the recent learning methods? In order to answer this question, we discuss various approaches to the learning task considered. We shortly describe the particular learning algorithms and report the results of experiments. Finally, we discuss the properties, assumptions and limitations of each method. We complete this review with a comprehensive list of pointers to the literature

Landfill leachate treatment in soil-plant systems ‒ possibilities of leachate dose rate selectionin initial plants growth

Infiltrujące przez hałdę odpadów wody opadowe, ługując związki chemiczne, generują powstawanie odcieków składowiskowych, których skład chemiczny przynajmniej kilkakrotnie przewyższa stężenia dopuszczalne ścieków wprowadzanych do wód i do ziemi. Zanieczyszczenia migrujące w głąb profilu glebowego powodują zagrożenie dla wód podziemnych i powierzchniowych. Powstaje konieczność unieszkodliwienia zbieranych odcieków. Najczęściej stosowaną metodą jest bezpośrednie kierowanie do oczyszczalni ścieków, w praktyce jednak oznacza to ich rozcieńczenie.Precipitation water infiltrating trough waste heap and extracting different chemical compounds, generate landfill leachate. Landfill leachate should be than collected, and effectively treated. One of the promising technologies of landfill leachate treatment is a considerable decrease in leachate volume due to evapotranspiration from the soil-plant systems. The decreasing of leachate volume in soil-plant system ensues due to evaporation supported by plants transpiration. In year 2006, the soil-plant systems with reed have been implemented at the landfill in Zakurzewo near Grudziądz, Poland. At the top of the one of the big waste piles, the soil-plant system with area of 2 500 m2 was built. The efficiency of leachate treatment is evaluated on the base of water balance considering the measurements of amount leachate pumped into the soilplant system, precipitation measurements, and meteorological data of evaporation measured with using Peach Evaporometer. The share of landfill leachate in total amount water supplied into soil-plant system was 24.4% during first year of operation and 37.6% in the second year. During second year, in the peak of vegetative season, the measurements of degree of opening leaf stomata (transpiration) of 100 reeds were done. The transpiration rate was measured by Porometer AP-4-UM-3 Delta-T Devices [mmol H2O.m-2∙s-1]. The results of measurements were used for assessment of reeds behavior in the toxic condition of landfill leachate supplying. During second year, July the mean value of reed degree leaf stomata opening was at the level 261.3 [mol∙m-2∙s-1]. Comparison, with laboratory results indicated strong adaptation force of reed growing at the landfill. The electrolytic conductance (EC) of the leachate gathered in the soil-plant system was 10.8 mS/cm. During laboratory tests similar reed transpiration rate - 250.3 [mol∙m-2∙s-1] was measured for solution with EC - 1.1 mS/cm. The lowest effective concentration causing toxic effect was on the level 7% of leachate. Research indicated that during initial plants growth the dose rate of leachate shouldn't exceed 7%

Visual simultaneous localisation and map-building supported by structured landmarks

Visual simultaneous localisation and map-building systems which take advantage of some landmarks other than point-wise environment features are not frequently reported. In the following paper the method of using the operational map of robot surrounding, which is complemented with visible structured passive landmarks, is described. These landmarks are used to improve self-localisation accuracy of the robot camera and to reduce the size of the Kalman-filter state-vector with respect to the vector size involving point-wise environment features only. Structured landmarks reduce the drift of the camera pose estimate and improve the reliability of the map which is built on-line. Results of simulation experiments are described, proving advantages of such an approach

An active vision system for a walking robot

Przedmiotem artykułu jest zbadanie możliwości zastosowania systemu wizyjnego wykorzystującego punktowy oświetlacz laserowy jako pokładowego sensora robota kroczącego. Zaproponowano model matematyczny określający zależności geometryczne w układzie kamera/laser/obiekt, wykorzystywany w algorytmach przetwarzania danych oraz procedurę jego kalibracji. Opracowano algorytm wyodrębniania śladu lasera z obrazu. Badania eksperymentalne pozytywnie zweryfikowały możliwość zastosowania rozważanego systemu jako dalmierza oraz do uzyskiwania informacji o geometrii sceny trójwymiarowej. Błędy względne metody pomiarowej nie przekroczyły 5%.This paper demonstrates the feasibility of a vision system, made of a camera and a laser-beam projector, as a on-board sensor for the walking robot. A mathematical model of the camera/laser/ object relationship used in data processing algorithms is proposed, with a procedure of its calibration. An algorithm for the extraction of the beam-pattern from the image was proposed. Real images acquired during an experiment were analyzed. As examples two scenes were tested. The object shapes were imaged properly. The system can be used as a rangefinder and 3D scene geometry explorer. Errors of the measurement method were below 5%. Than the system can be used for the collecting 3D information concerning the space directly ahead of the robot. Its advantage is low cost