49 research outputs found

    The Dynamics of 3-dimentional micro-mechanic sensor of angle motions of a robot-hexapod

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    Transfer function matrices of 3d MEMS sensor of angular motions and spectral density of noises measurements were estimated with the help of the method of structural identification for first time. This provides the possibility to control and operate the angle position of the platform of robot-hexapod

    The Dynamic Characteristics of the Manipulator With Parallel Kinematic Structure Based on Experimental Data

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    The chapter presents two identification techniques which the authors found most useful in examining the dynamic characteristics of a manipulator with a parallel kinematic structure as an object of control. These techniques emphasize a frequency domain approach. If all input/output signals of an object can be measured, then the first one of such techniques may be used for identification. In the case when all disturbances can’t be measured, the second identification technique may be used

    Багатовимірна структурна ідентифікація при регулярних сигналах

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    New structural identification algorithm at a regular signals for the multidimensional objects with unstable poles is discussed in this article. This algorithm is based on the use of transformation of Laplace for the decision of reverse control task. It allows to find the object transfer matrices from the control input and from the indignation input as a result of the quadratic functional minimization. Новий алгоритм структурної ідентифікації багатовимірних можливо нестійких об’єктів при регулярних сигналах розглянуто у статті. Зазначений алгоритм заснований на використанні перетворення Лапласу для розв’язання зворотної задачі керування. Він дозволяє знаходити матриці передатних функцій об’єкта від регульованого входу та від збурення в результаті мінімізації квадратичного функціоналу якості

    Optimal Control of Leader-Following Robots under Random Effects

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    The article focuses on the development of an on-board system design method for optimal control of an autonomous mobile group of objects. It is assumed that the group consists of a leader and some agents. A new method for the synthesis of an optimal multivariable control system, which is needed for preserving desired position of the agent relatively to the leader was substantiated in the article. The leader passes along a random trajectory and measurement of the agent position with respect to the leader is accompanied with random noise. All group members experience the action of random disturbances

    Fast Switching Ferroelectric Materials for Accelerator Applications

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    Fast switching (< 10 nsec) measurement results on the recently developed BST(M) (barium strontium titanium oxide composition with magnesium-based additions) ferroelectric materials are presented. These materials can be used as the basis for new advanced technology components suitable for high-gradient accelerators. A ferroelectric ceramic has an electric field-dependent dielectric permittivity that can be altered by applying a bias voltage. Ferroelectric materials offer significant benefits for linear collider applications, in particular, for switching and control elements where a very short response time of <10 nsec is required. The measurement results presented here show that the new BST(M) ceramic exhibits a high tunability factor: a bias field of 40-50 kV/cm reduces the permittivity by a factor of 1.3-1.5. The recently developed technology of gold biasing contact deposition on large diameter (110 cm) thin wall ferroelectric rings allowed ~few nsec switching times in witness sample experiments. The ferroelectric rings can be used at high pulsed power (tens of megawatts) for X-band components as well as at high average power in the range of a few kilowatts for the L-band phase-shifter, under development for optimization of the ILC rf coupling. Accelerator applications include fast active X-band and Ka-band high-power ferroelectric switches, high-power X-band and L-band phase shifters, and tunable dielectric-loaded accelerating structures.Comment: 7 pages, 6 figures, submitted to Proceedings of 2006 Advanced Accelerator Concepts Worksho

    Multi-view Face Detection Using Deep Convolutional Neural Networks

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    In this paper we consider the problem of multi-view face detection. While there has been significant research on this problem, current state-of-the-art approaches for this task require annotation of facial landmarks, e.g. TSM [25], or annotation of face poses [28, 22]. They also require training dozens of models to fully capture faces in all orientations, e.g. 22 models in HeadHunter method [22]. In this paper we propose Deep Dense Face Detector (DDFD), a method that does not require pose/landmark annotation and is able to detect faces in a wide range of orientations using a single model based on deep convolutional neural networks. The proposed method has minimal complexity; unlike other recent deep learning object detection methods [9], it does not require additional components such as segmentation, bounding-box regression, or SVM classifiers. Furthermore, we analyzed scores of the proposed face detector for faces in different orientations and found that 1) the proposed method is able to detect faces from different angles and can handle occlusion to some extent, 2) there seems to be a correlation between dis- tribution of positive examples in the training set and scores of the proposed face detector. The latter suggests that the proposed methods performance can be further improved by using better sampling strategies and more sophisticated data augmentation techniques. Evaluations on popular face detection benchmark datasets show that our single-model face detector algorithm has similar or better performance compared to the previous methods, which are more complex and require annotations of either different poses or facial landmarks.Comment: in International Conference on Multimedia Retrieval 2015 (ICMR

    Electroanatomic substrate of atrial fibrillation in patients after COVID-19

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    Aim. To determine the features of left atrial electroanatomic structure and the arrhythmia substrate in patients with atrial fibrillation (AF) after coronavirus disease 2019 (COVID-19).Material and methods. The pilot study included 20 patients with AF who underwent catheter radiofrequency ablation. Ten patients had COVID-19 and 10 patients were included as a control group. AF substrate was identified using anatomic and bipolar mapping. Zones with following amplitudes were analyzed: &lt;0,25 mV, &lt;0,5 mV, from 0,5 to 0,75 mV inclusive, and &gt;0,75 mV. Left atrial volume was determined based on anatomic map.Results. The groups were homogeneous in AF type, number of patients after prior pulmonary vein isolation, and heart rate during mapping. In the COVID-19 group, there was a higher area of fibrous zones with an amplitude of &lt;0,25 mV (51,5±16,6% vs 29,1±16,1% in the control group, p=0,007), &lt;0,5 mV (76,7±11,5% vs 45,6±22,7% in the control group, p=0,001) and a lower area of intact myocardium with an amplitude &gt;0,75 mV (11,6±8,0% vs 45,0±25,0% in the control group, p=0,001). In 7 COVID-19 patients, the posterior wall was isolated due to low-amplitude zones. Of these, three patients underwent surgery for the first time. According to ROC analysis, in patients after COVID-19, fibrous tissue (&lt;0,5 mV) occupies more than half of the area, while normal tissue (&gt;0,75 mV) — ~30% or less.Conclusion. This study shows that SARS-CoV-2 infection may cause left atrial remodeling in the form of diffuse fibrosis. The arrhythmia substrate in patients after COVID-19 can be localized not only in pulmonary vein mouths, but also in other left atrial areas. This must be taken into account before ablation, even if the procedure is being performed for the first time. It is recommended to perform amplitude mapping for all patients who have had SARS-CoV-2 infection in order to identify fibrous zones and plan the operation extent

    Some novel ways of gastric cancer patients treatment personification

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    In this paper the authors perform the analysis of molecular and morphological factors influencing the survival of patients with gastric cancer (n = 221). They analyzed the survival rate in this group of patients based on the analysis of molecular markers VEGFR, p53, Her2, Ki-67. Measured role in the survival such factors as the degree of differentiation of primary gastric tumors, the presence of microscopic tumor involvement of perineural and perivascular spaces, the degree of invasion to gastric wall by T1 = 1 and to T4a = 4, T4b = 5, number of regional lymph nodes affected by metastasis, and other factors. As an arbitrator used survival curves calculated by the method of R. J. Cox, time of lifespan, measured in months, as well as a comparison of the areas under the curves of survival
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