Point cloud hand-object segmentation using multimodal imaging with thermal and color data for safe robotic object handover

This paper presents an application of neural networks operating on multimodal 3D data (3D point cloud, RGB, thermal) to effectively and precisely segment human hands and objects held in hand to realize a safe human–robot object handover. We discuss the problems encountered in building a multimodal sensor system, while the focus is on the calibration and alignment of a set of cameras including RGB, thermal, and NIR cameras. We propose the use of a copper–plastic chessboard calibration target with an internal active light source (near-infrared and visible light). By brief heating, the calibration target could be simultaneously and legibly captured by all cameras. Based on the multimodal dataset captured by our sensor system, PointNet, PointNet++, and RandLA-Net are utilized to verify the effectiveness of applying multimodal point cloud data for hand–object segmentation. These networks were trained on various data modes (XYZ, XYZ-T, XYZ-RGB, and XYZ-RGB-T). The experimental results show a significant improvement in the segmentation performance of XYZ-RGB-T (mean Intersection over Union: 82.8% by RandLA-Net) compared with the other three modes (77.3% by XYZ-RGB, 35.7% by XYZ-T, 35.7% by XYZ), in which it is worth mentioning that the Intersection over Union for the single class of hand achieves 92.6%

How a Digital Educational Game can Promote Learning about Sustainability

Education for Sustainable Development (ESD) has become an essential issue for schools facing major challenges such as bridging the knowledge-action-gap. Interactive simulations could help to focus on action-oriented learning. As part of a design-based research (DBR) process, we investigated the learning potential of game elements within a digital educational game for ESD we are currently developing. The final game aims to convey specific aspects of ESD ranging from sustainable land use to personal power consumption. Seven groups of 2–3 secondary school students (9th and 10th grade, n = 18) played the educational game in an early prototype phase. Following the DBR approach, students were shown screenshots of specific game situations in subsequent group interviews to reveal their conceptions and conceptual developments regarding sustainability. To analyze the causes of possible learning processes, we used the retrospective query on the learning process and qualitative content analysis. The results indicate that the observed learning processes can be primarily traced back to feedback mechanisms and the visualization of processes that would be too complex and long-termed to be experienced by students in real-life. This is how a simulation game, which makes complex interrelations tangible, can contribute to ESD. The possibility to make decisions and act (digitally) within the game allowed students to experience immediate feedback and self-efficacy. Therefore, the easily accessible visualizations and the immediate feedback are essential elements for the final game. It appears however necessary to embed the game in well-structured reflective processes. The study also contributes to adaptive game-based learning as a growing branch of research in which game elements are adopted and adapted for learning based on learner characteristics and the thematic context

Исследование влияния параметров нефтяного шлама на характеристики шнекового дозатора

Работа посвящена определению конструктивных особенностей шнекового дозатора при различных параметрах и свойствах нефтяного шлама при его подаче на установку по переработке нефтяных отходов производительностью 1000 кг/ч.The work is devoted to determining the design features of a screw dispenser with various parameters and properties of oil sludge when it is fed to an oil waste processing plant with a capacity of 1000 kg/hr

Muon Track Reconstruction and Data Selection Techniques in AMANDA

The Antarctic Muon And Neutrino Detector Array (AMANDA) is a high-energy neutrino telescope operating at the geographic South Pole. It is a lattice of photo-multiplier tubes buried deep in the polar ice between 1500m and 2000m. The primary goal of this detector is to discover astrophysical sources of high energy neutrinos. A high-energy muon neutrino coming through the earth from the Northern Hemisphere can be identified by the secondary muon moving upward through the detector. The muon tracks are reconstructed with a maximum likelihood method. It models the arrival times and amplitudes of Cherenkov photons registered by the photo-multipliers. This paper describes the different methods of reconstruction, which have been successfully implemented within AMANDA. Strategies for optimizing the reconstruction performance and rejecting background are presented. For a typical analysis procedure the direction of tracks are reconstructed with about 2 degree accuracy.Comment: 40 pages, 16 Postscript figures, uses elsart.st

On the selection of AGN neutrino source candidates for a source stacking analysis with neutrino telescopes

The sensitivity of a search for sources of TeV neutrinos can be improved by grouping potential sources together into generic classes in a procedure that is known as source stacking. In this paper, we define catalogs of Active Galactic Nuclei (AGN) and use them to perform a source stacking analysis. The grouping of AGN into classes is done in two steps: first, AGN classes are defined, then, sources to be stacked are selected assuming that a potential neutrino flux is linearly correlated with the photon luminosity in a certain energy band (radio, IR, optical, keV, GeV, TeV). Lacking any secure detailed knowledge on neutrino production in AGN, this correlation is motivated by hadronic AGN models, as briefly reviewed in this paper. The source stacking search for neutrinos from generic AGN classes is illustrated using the data collected by the AMANDA-II high energy neutrino detector during the year 2000. No significant excess for any of the suggested groups was found.Comment: 43 pages, 12 figures, accepted by Astroparticle Physic

Search for Neutrino-Induced Cascades with AMANDA

We report on a search for electro-magnetic and/or hadronic showers (cascades) induced by high energy neutrinos in the data collected with the AMANDA II detector during the year 2000. The observed event rates are consistent with the expectations for atmospheric neutrinos and muons. We place upper limits on a diffuse flux of extraterrestrial electron, tau and muon neutrinos. A flux of neutrinos with a spectrum $\Phi \propto E^{-2}$ which consists of an equal mix of all flavors, is limited to $E^2 \Phi(E)=8.6 x 10^{-7} GeV/(cm^{2} s sr)$ at a 90% confidence level for a neutrino energy range 50 TeV to 5 PeV. We present bounds for specific extraterrestrial neutrino flux predictions. Several of these models are ruled out.Comment: 18 pages, 12 figure