148 research outputs found

    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

    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

    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

    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

    Equality of the bulk and edge Hall conductances in a mobility gap

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    We consider the edge and bulk conductances for 2D quantum Hall systems in which the Fermi energy falls in a band where bulk states are localized. We show that the resulting quantities are equal, when appropriately defined. An appropriate definition of the edge conductance may be obtained through a suitable time averaging procedure or by including a contribution from states in the localized band. In a further result on the Harper Hamiltonian, we show that this contribution is essential. In an appendix we establish quantized plateaus for the conductance of systems which need not be translation ergodic.Comment: 38 pages, LaTeX, uses svjour class. Corrected a number of typos and an error in proof of Lemma four. The latter correction appears as a separate erratum in the published version. Additional typos corrected in v

    Financial statements of a company as an information base for decision-making in a transforming economy

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    In connection with the development of transforming the economy, the need for forecasting and analyzing the consequences of managerial decisions becomes more pressing. To substantiate and evaluate such decisions, a tool for prospective analysis of financial statements of companies is used. In recent years, the content and structure of a company's financial statements have undergone significant changes. With the development of economic relations, the principles of organization and methodology of accounting and reporting are also dynamically changing. The issues of reforming financial statements of a company are constantly discussed at international congresses of accountants and other professional forums. The purpose of the study is to improve the concept of preparing financial statements of a company as an information base for taking decisions in a transforming economy. As a result of the research, the economic essence of company's financial statements is substantiated from the point of view of an integrated approach; the importance of financial statements of an organization for effective management is determined; the main financial and non-financial indicators are systematized; it is proposed to introduce a mandatory requirement for disclosure of non-financial indicators in the corporate reporting system; proposals have been elaborated to improve the methods for analyzing financial statements as a tool for managing a company.peer-reviewe

    Security and Efficiency Analysis of the Hamming Distance Computation Protocol Based on Oblivious Transfer

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    open access articleBringer et al. proposed two cryptographic protocols for the computation of Hamming distance. Their first scheme uses Oblivious Transfer and provides security in the semi-honest model. The other scheme uses Committed Oblivious Transfer and is claimed to provide full security in the malicious case. The proposed protocols have direct implications to biometric authentication schemes between a prover and a verifier where the verifier has biometric data of the users in plain form. In this paper, we show that their protocol is not actually fully secure against malicious adversaries. More precisely, our attack breaks the soundness property of their protocol where a malicious user can compute a Hamming distance which is different from the actual value. For biometric authentication systems, this attack allows a malicious adversary to pass the authentication without knowledge of the honest user's input with at most O(n)O(n) complexity instead of O(2n)O(2^n), where nn is the input length. We propose an enhanced version of their protocol where this attack is eliminated. The security of our modified protocol is proven using the simulation-based paradigm. Furthermore, as for efficiency concerns, the modified protocol utilizes Verifiable Oblivious Transfer which does not require the commitments to outputs which improves its efficiency significantly

    Ідентифікація сигналів в трактах керування платформи гексапода

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    The paper deals method of identification useful signals, the disturbance and interference operatinghexapod platform management system for modeling large-scale marine spatial pitching shipПроведена идентификация полезных сигналов, возмущений и помех, действующих в системе управления платформы гексапода при моделировании пространственной качки крупнотоннажного морского суднаПроведено ідентифікацію корисних сигналів, збурень і завад, що діють у системі керування платформи гексаподапри моделюванні просторової качки крупнотонажного морського судн
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