Исследование роботизированной мобильной платформы KUKA youBot

Объектом исследования является роботизированная мобильная платформа KUKA youBot, которая предназначена для решения исследовательских и промышленных задач. В основу научных исследований данной работы положены методы математического (обзор описания кинематики и динамики робота) и компьютерного моделирования (имитационное моделирование). Цель работы – изучение кинематики и динамики KUKA youBot, разработка программного обеспечения для решения простых робототехнических задач и обучения студентов основам работы с данным роботом. В процессе исследования произведён аналитический обзор по данной теме, разработано ПО для решения базовых робототехнических задач.The target of research is the robotic mobile platform KUKA youBot, which is designed to solve research and industrial problems. The scientific research of this work is based on methods of mathematical (review of the description of kinematics and robot dynamics) and computer modeling (simulation modeling). The work objective is to study the kinematics and dynamics of KUKA youBot, to develop software for solving simple robotic tasks and to teach students the basics of working with this robot. During the research, an analytical review on this topic was made, software for solving basic robotic tasks was developed

Women with a History of Recurrent Pregnancy Loss Are a High-Risk Population for Adverse Obstetrical Outcome:A Retrospective Cohort Study

Recurrent pregnancy loss (RPL), defined as three or more consecutive miscarriages, is hypothesized to share some of the same pathogenic factors as placenta-associated disorders. It has been hypothesized that a defect implantation causes pregnancy loss, while a partially impaired implantation may lead to late pregnancy complications. The aim of this retrospective register-based cohort study was to study the association between RPL and such disorders including pre-eclampsia, stillbirth, small for gestational age (SGA) birth, preterm birth and placental abruption. Women registered with childbirth(s) in the Swedish Medical Birth Register (MFR) were included in the cohort. Pregnancies of women diagnosed with RPL (exposed) in the National Patient Register (NPR), were compared with pregnancies of women without RPL (unexposed/reference). Obstetrical outcomes, in the first pregnancy subsequent to the diagnosis of RPL (n = 4971), were compared with outcomes in reference-pregnancies (n = 57,410). Associations between RPL and placental dysfunctional disorders were estimated by odds ratios (AORs) adjusting for confounders, with logistic regression. RPL women had an increased risk for pre-eclampsia (AOR 1.45; 95% CI; 1.24– 1.69), stillbirth <37 gestational weeks (GWs) (AOR 1.92; 95% CI; 1.22–3.02), SGA birth (AOR 1.97; 95% CI; 1.42–2.74), preterm birth (AOR 1.46; 95% CI; 1.20–1.77), and placental abruption <37 GWs (AOR 2.47; 95% CI; 1.62–3.76) compared with pregnancies by women without RPL. Women with RPL had an increased risk of pregnancy complications associated with placental dysfunction. This risk population is, therefore, in need of improved antenatal surveillance

Synthesis of glycolide by depolimerization of glycolic acid oligomers modified by polyhydric alcohols

Oligomers of glycolic acid esterified by ethylene glycol, propylene glycol, glycerin were obtained. These samples were depolymerized with various oxide catalysts such as MgO, ZnO, SnO[2] and Sb[2]O[3]. The resulting glycolide was analyzed by gas chromatography in different eluents - acetonitrile and hexafluoroisopropanol. It was shown that modification of glycolic acid oligomers by polyhydric alcohols reduces the content of hydroxyl containing impurities in raw glycolide

Aging in Dense Colloids as Diffusion in the Logarithm of Time

The far-from-equilibrium dynamics of glassy systems share important phenomenological traits. A transition is generally observed from a time-homogeneous dynamical regime to an aging regime where physical changes occur intermittently and, on average, at a decreasing rate. It has been suggested that a global change of the independent time variable to its logarithm may render the aging dynamics homogeneous: for colloids, this entails diffusion but on a logarithmic time scale. Our novel analysis of experimental colloid data confirms that the mean square displacement grows linearly in time at low densities and shows that it grows linearly in the logarithm of time at high densities. Correspondingly, pairs of particles initially in close contact survive as pairs with a probability which decays exponentially in either time or its logarithm. The form of the Probability Density Function of the displacements shows that long-ranged spatial correlations are very long-lived in dense colloids. A phenomenological stochastic model is then introduced which relies on the growth and collapse of strongly correlated clusters ("dynamic heterogeneity"), and which reproduces the full spectrum of observed colloidal behaviors depending on the form assumed for the probability that a cluster collapses during a Monte Carlo update. In the limit where large clusters dominate, the collapse rate is ~1/t, implying a homogeneous, log-Poissonian process that qualitatively reproduces the experimental results for dense colloids. Finally an analytical toy-model is discussed to elucidate the strong dependence of the simulation results on the integrability (or lack thereof) of the cluster collapse probability function.Comment: 6 pages, extensively revised, final version; for related work, see http://www.physics.emory.edu/faculty/boettcher/ or http://www.fysik.sdu.dk/staff/staff-vip/pas-personal.htm

An Introduction to PYTHIA 8.2

The PYTHIA program is a standard tool for the generation of events in high-energy collisions, comprising a coherent set of physics models for the evolution from a few-body hard process to a complex multiparticle final state. It contains a library of hard processes, models for initial- and final-state parton showers, matching and merging methods between hard processes and parton showers, multiparton interactions, beam remnants, string fragmentation and particle decays. It also has a set of utilities and several interfaces to external programs. PYTHIA 8.2 is the second main release after the complete rewrite from Fortran to C++, and now has reached such a maturity that it offers a complete replacement for most applications, notably for LHC physics studies. The many new features should allow an improved description of data.Comment: 45 page

Ultralow‐parameter denoising: trainable bilateral filter layers in computed tomography

Background Computed tomography (CT) is widely used as an imaging tool to visualize three-dimensional structures with expressive bone-soft tissue contrast. However, CT resolution can be severely degraded through low-dose acquisitions, highlighting the importance of effective denoising algorithms. Purpose Most data-driven denoising techniques are based on deep neural networks, and therefore, contain hundreds of thousands of trainable parameters, making them incomprehensible and prone to prediction failures. Developing understandable and robust denoising algorithms achieving state-of-the-art performance helps to minimize radiation dose while maintaining data integrity. Methods This work presents an open-source CT denoising framework based on the idea of bilateral filtering. We propose a bilateral filter that can be incorporated into any deep learning pipeline and optimized in a purely data-driven way by calculating the gradient flow toward its hyperparameters and its input. Denoising in pure image-to-image pipelines and across different domains such as raw detector data and reconstructed volume, using a differentiable backprojection layer, is demonstrated. In contrast to other models, our bilateral filter layer consists of only four trainable parameters and constrains the applied operation to follow the traditional bilateral filter algorithm by design. Results Although only using three spatial parameters and one intensity range parameter per filter layer, the proposed denoising pipelines can compete with deep state-of-the-art denoising architectures with several hundred thousand parameters. Competitive denoising performance is achieved on x-ray microscope bone data and the 2016 Low Dose CT Grand Challenge data set. We report structural similarity index measures of 0.7094 and 0.9674 and peak signal-to-noise ratio values of 33.17 and 43.07 on the respective data sets. Conclusions Due to the extremely low number of trainable parameters with well-defined effect, prediction reliance and data integrity is guaranteed at any time in the proposed pipelines, in contrast to most other deep learning-based denoising architectures

The Molecular Epidemiology of the Highly Virulent ST93 Australian Community Staphylococcus aureus Strain

In Australia the PVL - positive ST93-IV [2B], colloquially known as ‘‘Queensland CA-MRSA’’ has become the dominant CA-MRSA clone. First described in the early 2000s, ST93-IV [2B] is associated with skin and severe invasive infections including necrotizing pneumonia. A singleton by multilocus sequence typing (MLST) eBURST analysis ST93 is distinct from other S aureus clones. To determine if the increased prevalence of ST93-IV [2B] is due to the widespread transmission of a single strain of ST93-IV [2B] the genetic relatedness of 58 S. aureus ST93 isolated throughout Australia over an extended period were studied in detail using a variety of molecular methods including pulsed-field gel electrophoresis, spa typing, MLST, microarray DNA, SCCmec typing and dru typing. Identification of the phage harbouring the lukS-PV/lukF-PV Panton Valentine leucocidin genes, detection of allelic variations in lukS-PV/lukF-PV, and quantification of LukF-PV expression was also performed. Although ST93-IV [2B] is known to have an apparent enhanced clinical virulence, the isolates harboured few known virulence determinants. All PVL-positive isolates carried the PVL-encoding phage WSa2USA and the lukS-PV/lukF-PV genes had the same R variant SNP profile. The isolates produced similar expression levels of LukF-PV. Although multiple rearrangements of the spa sequence have occurred, the core genome in ST93 is very stable.The emergence of ST93-MRSA is due to independent acquisitions of different dru-defined type IV and type V SCCmec elements in several spa-defined ST93-MSSA backgrounds. Rearrangement of the spa sequence in ST93-MRSA has subsequently occurred in some of these strains. Although multiple ST93-MRSA strains were characterised, little genetic diversity was identified for most isolates, with PVLpositive ST93-IVa [2B]-t202-dt10 predominant across Australia. Whether ST93-IVa [2B] t202-dt10 arose from one PVL-positive ST93-MSSA-t202, or by independent acquisitions of SCCmec-IVa [2B]-dt10 into multiple PVL-positive ST93-MSSA-t202 strains is not known

Reduction of continuous symmetries of chaotic flows by the method of slices

We study continuous symmetry reduction of dynamical systems by the method of slices (method of moving frames) and show that a `slice' defined by minimizing the distance to a single generic `template' intersects the group orbit of every point in the full state space. Global symmetry reduction by a single slice is, however, not natural for a chaotic / turbulent flow; it is better to cover the reduced state space by a set of slices, one for each dynamically prominent unstable pattern. Judiciously chosen, such tessellation eliminates the singular traversals of the inflection hyperplane that comes along with each slice, an artifact of using the template's local group linearization globally. We compute the jump in the reduced state space induced by crossing the inflection hyperplane. As an illustration of the method, we reduce the SO(2) symmetry of the complex Lorenz equations.Comment: to appear in "Comm. Nonlinear Sci. and Numer. Simulat. (2011)" 12 pages, 8 figure