98 research outputs found

    Scheduling algorithms for automatic control systems for technological processes

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    Wide use of automatic process control systems and the usage of high-performance systems containing a number of computers (processors) give opportunities for creation of high-quality and fast production that increases competitiveness of an enterprise. Exact and fast calculations, control computation, and processing of the big data arrays - all of this requires the high level of productivity and, at the same time, minimum time of data handling and result receiving. In order to reach the best time, it is necessary not only to use computing resources optimally, but also to design and develop the software so that time gain will be maximal. For this purpose task (jobs or operations), scheduling techniques for the multi-machine/multiprocessor systems are applied. Some of basic task scheduling methods for the multi-machine process control systems are considered in this paper, their advantages and disadvantages come to light, and also some usage considerations, in case of the software for automatic process control systems developing, are made

    Identification method based on Zadeh filter models

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    Mathematical modeling which provides the description of objects and proper organization of control operations in future is an integral stage in the automation of production. One of the approaches to build a mathematical model of an object is to represent nonlinear systems as combinations of inertial and nonlinear inertialess elements. The models thus obtained are called block-oriented. In this paper, we consider nonlinear dynamic objects represented as the models of the Zadeh filter class. In the process of the method development the identification equations were derived for the case when the test signal is a single sinusoid. Then the case of two sinusoids was considered. Such investigations allowed us to identify the patterns and describe the general case for several test components in the signal. The results of digital modeling using the sum of harmonic signals confirm the feasibility and validity of the proposed approach for identifying nonlinear models of the Zadeh filter class

    Hydrodynamic reductions of the heavenly equation

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    We demonstrate that Pleba\'nski's first heavenly equation decouples in infinitely many ways into a triple of commuting (1+1)-dimensional systems of hydrodynamic type which satisfy the Egorov property. Solving these systems by the generalized hodograph method, one can construct exact solutions of the heavenly equation parametrized by arbitrary functions of a single variable. We discuss explicit examples of hydrodynamic reductions associated with the equations of one-dimensional nonlinear elasticity, linearly degenerate systems and the equations of associativity.Comment: 14 page

    Classification of integrable hydrodynamic chains and generating functions of conservation laws

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    New approach to classification of integrable hydrodynamic chains is established. Generating functions of conservation laws are classified by the method of hydrodynamic reductions. N parametric family of explicit hydrodynamic reductions allows to reconstruct corresponding hydrodynamic chains. Plenty new hydrodynamic chains are found

    Loewner equations, Hirota equations and reductions of universal Whitham hierarchy

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    This paper reconsiders finite variable reductions of the universal Whitham hierarchy of genus zero in the perspective of dispersionless Hirota equations. In the case of one-variable reduction, dispersionless Hirota equations turn out to be a powerful tool for understanding the mechanism of reduction. All relevant equations describing the reduction (L\"owner-type equations and diagonal hydrodynamic equations) can be thereby derived and justified in a unified manner. The case of multi-variable reductions is not so straightforward. Nevertheless, the reduction procedure can be formulated in a general form, and justified with the aid of dispersionless Hirota equations. As an application, previous results of Guil, Ma\~{n}as and Mart\'{\i}nez Alonso are reconfirmed in this formulation.Comment: latex 2e using packages amsmath,amssymb,amsthm, 39 pages, no figure; (v2) a few typos corrected and accepted for publicatio

    Nonlinear diffraction of light beams propagating in photorefractive media with embedded reflecting wire

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    The theory of nonlinear diffraction of intensive light beams propagating through photorefractive media is developed. Diffraction occurs on a reflecting wire embedded in the nonlinear medium at relatively small angle with respect to the direction of the beam propagation. It is shown that this process is analogous to the generation of waves by a flow of a superfluid past an obstacle. The ``equation of state'' of such a superfluid is determined by the nonlinear properties of the medium. On the basis of this hydrodynamic analogy, the notion of the ``Mach number'' is introduced where the transverse component of the wave vector plays the role of the fluid velocity. It is found that the Mach cone separates two regions of the diffraction pattern: inside the Mach cone oblique dark solitons are generated and outside the Mach cone the region of ``ship waves'' is situated. Analytical theory of ``ship waves'' is developed and two-dimensional dark soliton solutions of the equation describing the beam propagation are found. Stability of dark solitons with respect to their decay into vortices is studied and it is shown that they are stable for large enough values of the Mach number.Comment: 18 page

    Prospects in Analytical Atomic Spectrometry

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    Tendencies in five main branches of atomic spectrometry (absorption, emission, mass, fluorescence and ionization spectrometry) are considered. The first three techniques are the most widespread and universal, with the best sensitivity attributed to atomic mass spectrometry. In the direct elemental analysis of solid samples, the leading roles are now conquered by laser-induced breakdown and laser ablation mass spectrometry, and the related techniques with transfer of the laser ablation products into inductively-coupled plasma. Advances in design of diode lasers and optical parametric oscillators promote developments in fluorescence and ionization spectrometry and also in absorption techniques where uses of optical cavities for increased effective absorption pathlength are expected to expand. Prospects for analytical instrumentation are seen in higher productivity, portability, miniaturization, incorporation of advanced software, automated sample preparation and transition to the multifunctional modular architecture. Steady progress and growth in applications of plasma- and laser-based methods are observed. An interest towards the absolute (standardless) analysis has revived, particularly in the emission spectrometry.Comment: Proofread copy with an added full reference list of 279 citations. A pdf version of the final published review may be requested from Alexander Bol'shakov <[email protected]

    Эффективность и безопасность комбинированного применения целекоксиба, диацереина и комбинации глюкозамина и хондроитина для контроля скелетно-мышечной боли, связанной с остеоартритом и неспецифической болью в спине

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       The combined use of drugs with different mechanisms of action is the main principle of musculoskeletal pain control in rheumatic diseases. However, there are few studies evaluating the efficacy of this approach in real practice.Objective: to determine the efficacy and safety of the combined use of celecoxib, diacerein, and the combination of glucosamine + chondroitin in osteoarthritis (OA) and chronic nonspecific low back pain (NSLBP).   Material and methods. Statistical analysis of data obtained during a 3-month open observational study was performed. We included 1569 patients (63.6 % women and 36.4 % men, mean age 58.7 ± 11.0 years) with knee OA (kOA), hip OA (hOA), generalized OA (gOA), and chronic NSLBP with moderate/severe pain (≥ 4 on a numeric rating scale, NRS 0–10) who required nonsteroidal anti-inflammatory drugs. Celecoxib 200 mg twice daily was prescribed, with the dose reduced to 200 mg per day or taken “as needed" after significant pain relief; diacerein 50 mg twice daily; and a medication of glucosamine 250 mg and chondroitin 200 mg, 2 capsules 2–3 times daily. Outcomes were assessed after 3 months using the dynamics of pain, fatigue, dysfunction (according to NRS), and the “Patient Acceptable Symptom State” (PASS) indicator.   Results and discussion. 80.2 % of patients completed the 3 month course of treatment, 4.4 % discontinued treatment due to adverse events (AEs), and for 15.4 % of patients there was no follow-up. After 3 months of treatment ≥ 50 % decrease (from baseline) in the severity of symptoms was noted in 83.4 % of patients for pain on movement, in 83.7 % for pain at rest, in 78.6 % for pain at night, in 80.8 % for dysfunction, and in 83.4 % for fatigue. 87.7 % of patients reported PASS. There were no significant differences in treatment outcomes for different localizations of OA and NSLBP: a ≥ 50 % pain reduction in kOA was achieved in 81.6 % of patients, in hOA – in 82.2 %, in gOA – in 85.0 %, in NSLBP – in 88.1 %. AEs were registered in 350 (22.4 %) patients, the most frequent was dyspepsia (n = 280, 17.8 %), diarrhea was recorded in 37 (2.4 %) cases. No serious AEs requiring hospitalization were registered.   Conclusion. Combination therapy with celecoxib, diacerein, and a combination of glucosamine and chondroitin significantly reduces the severity of symptoms of OA and NSLBS.   Комплексное применение препаратов с различным механизмом  действия – основной принцип контроля скелетно-мышечной боли при ревматических заболеваниях. Однако имеется лишь небольшое число работ, в которых оценивается эффективность такого подхода в реальной практике.   Цель исследования – определение эффективности и безопасности сочетанного применения целекоксиба, диацереина и комбинации глюкозамин + хондроитин при остеоартрите (ОА) и хронической неспецифической боли в спине (НБС).   Материал и методы. Выполнен статистический анализ данных, полученных в ходе 3-месячного открытого наблюдательного исследования. Было включено 1569 пациентов (63,6 % женщин и 36,4 % мужчин, средний возраст – 58,7 ± 11,0 года) с ОА коленного (КС), тазобедренного (ТБС) суставов, генерализованным ОА (ГОА) и хронической НБС, испытываваших умеренную/выраженную боль (≥ 4 по числовой рейтинговой шкале, ЧРШ 0–10) и нуждавшихся в приеме нестероидных противовоспалительных препаратов. Назначались целекоксиб 200 мг 2 раза в сутки со снижением дозы до 200 мг/сут и использованием «по требованию» после значительного уменьшения боли; диацереин 50 мг 2 раза в сутки и препарат глюкозамина 250 мг и хондроитина 200 мг по 2 капсулы 2–3 раза в день. Оценка результатов проводилась через 3 мес по динамике боли, усталости, нарушения функции (по ЧРШ), а также показателю «состояние симптомов, приемлемое для пациента» (ССПП).   Результаты и обсуждение. 3-месячный курс лечения закончили 80,2 % больных, 4,4 % прервали лечение из-за нежелательных явлений (НЯ), 15,4 % выпали из-под наблюдения. Через 3 мес уменьшение выраженности ≥ 50 % по сравнению с исходным уровнем для боли при движении отмечено у 83,4 % пациентов, боли в покое – у 83,7 %, боли ночью – у 78,6 %, нарушения функции – у 80,8 %, усталости – у 83,4 %; 87,7 % пациентов указали на ССПП. Не выявлено значимых различий результатов лечения при различной локализации ОА и НБС: ≥ 50 % уменьшение боли при ОА КС достигнуто у 81,6 % больных, при ОА ТБС – у 82,2 %, при ГОА – у 85,0 %, при НБС – у 88,1 %. НЯ зарегистрированы у 350 (22,4 %) пациентов, наиболее часто встречалась диспепсия (n = 280, 17,8 %), диарея отмечалась в 37 (2,4 %) случаях. Серьезные НЯ, потребовавшие госпитализации, не зафиксированы.   Заключение. Комбинированная терапия с использованием целекоксиба, диацереина и комбинации глюкозамина и хондроитина обеспечивает существенное уменьшение выраженности симптомов ОА и НБС
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