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1
Leles, Michel Carlo Rodrigues, Leonardo Amaral Mozelli, Cairo Lúcio Nascimento Júnior, Elton Felipe Sbruzzi et Homero Nogueira Guimarães. « Study on Singular Spectrum Analysis as a New Technical Oscillator for Trading Rules Design ». Fluctuation and Noise Letters 17, no 04 (14 septembre 2018) : 1850034. http://dx.doi.org/10.1142/s0219477518500347.
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The connection between Singular Spectrum Analysis (SSA) decomposition and short-term market movements is investigated. Since SSA is a non-parametric approach, suitable to decompose general time-series into meaningful components, such as trends, oscillations and noise, it is proposed as a new oscillator-type Technical Indicator, replacing popular ones. New Technical Trading Rules (TTRs) are designed and applied to some major global stock indexes to illustrate the benefits in terms of revealing market movements. The performance is evaluated according to different risk-adjustment metrics and the empirical results reveal that the SSA-TTRs may outperform some popular technical oscillators and also the Buy & Hold strategy.
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Popov, I. P. « MATHEMATICAL MODELING OF A MULTI-INERT OSCILLATORY MECHANISM ». Bulletin of the South Ural State University series "Mechanical Engineering Industry" 20, no 1 (2020) : 22–29. http://dx.doi.org/10.14529/engin200103.
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It is noted that the free harmonic vibrations of a classical pendulum are due to the mutual conversion of the kinetic energy of the load intothe potential energy of the spring. Oscillators with a different nature of energy exchange have been developed, for example, by converting the kinetic energy of a load into the energy of a magnetic field of a solenoid or the energy of an electric field of a capacitor. All these oscillatory systems and the like were a prerequisite for the creation of a biinert oscillator,in which the acceleration of one load occurs due to the braking of another, i. e. only kinetic energies are exchanged. The aim of the work is mathematical modeling of a multi-inert oscillatory mechanism. The main research methods in the framework of this work are methods of mathematical modeling and analysis. The methods used make it possible to obtain a reliable description of the studied objects. Inthe proposed multi-inert oscillator, inert bodies of mass m each carry out harmonic oscillations due to the mutual exchange of kinetic energy. The potential energy of the springs is not requiredfor this. Body vibrationsare free. A feature of a multi-inert oscillator is that the frequency of itsfree oscillations is not fixed and is determined mainly by the initial conditions. This feature can be very useful for technical applications, for example, for self-neutralization of mechanical reactive (inertial) power. n-gon, formed by inert bodies, carries out complex motion – orbital rotation around the center of coordinates and spin rotation around its axis passing through the center of the n-gon. Moreover, each load performs linear harmonic oscillations along its guide. With the arrangement of the guiding weights not in the form of a star, but in parallel to each other, the angles between the corresponding cranks must be 360/n degrees.
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Nusinovich, G. S., et O. Dumbrajs. « Technical noise in gyroklystrons and phase-locked gyrotron oscillators ». Physics of Plasmas 4, no 5 (mai 1997) : 1424–33. http://dx.doi.org/10.1063/1.872317.
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Dennai, Brahim, Abdelhak Bentaleb, Tawfiq Chekifi, Rachid Khelfaoui et Asma Abdenbi. « Micro Fluidic Oscillator : A Technical Solution for Micro Mixture ». Advanced Materials Research 1064 (décembre 2014) : 213–18. http://dx.doi.org/10.4028/www.scientific.net/amr.1064.213.
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The diffusion flux given by the Fick’s law characterizethe mixing rate. A passive mixing strategy is proposed to enhance mixing of two fluids through perturbed jet low. A numerical study of passive mixers has been presented. This paper is focused on the modeling of a micro-injection systems composed of passive amplifier without mechanical part. The micro-system modeling is based on geometrical oscillators form. An asymmetric micro-oscillator design based on a monostable fluidic amplifier is proposed [2,7]. The characteristic size of the channels is generally about a few hundred of microns. The numerical results indicate that the mixing performance can be as high as 99 % within a typical mixing chamber of0.20 mm diameter inlet and 2.0 mm distance of nozzle - spliter. In addition, the results confirm that self-rotation in the circular mixer significantly enhances the mixing performance. The novel micro mixing method presented in this study provides a simple solution to mixing problems in microsystem.
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Lyagov, A. V., I. A. Lyagov et I. N. Suleymanov. « Anti-vibration - stabilizing drill bottomhole assembly for «Perfobore» technical system ». SOCAR Proceedings, no 4 (30 décembre 2020) : 24–32. http://dx.doi.org/10.5510/ogp20200400462.
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The article discusses the method of bottomhole assembly (BHA) for the «Perfobore» technical system, investigated as a complex of elastic-viscous working elements - coupled oscillators located in a dynamically disturbed section of the assembly. The length of the section is determined using the group velocity of propagation of the energy of a packet of quasi-harmonic waves differing from each other in phase and frequency, with prevailing natural frequencies, which are calculated after statistical processing of the obtained dynamograms of phase trajectories. Then, the working elements of the technical system are assembled with selected natural frequencies and taking into account various bending and torsional stiffnesses of the component assemblies (oscillators), and the damping properties of the assemblies are enhanced by the additional placement of hydromechanical axial load regulators with a variable vibration isolation coefficient in the calculated places of the «motion stability nodes».
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Oliver, J. « Analysis and classification of technical analysis indicators by support vector machines ». Finance, Markets and Valuation 4, no 1 (2018) : 59–66. http://dx.doi.org/10.46503/hddl8238.
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The search for models which can accurately forecast the market trend has developed over the past decades. Technical indicators and oscillators are the most usually employed inputs in the prediction models. These inputs basically rely on prices and the evolution of the index itself, which may cause some problems like multicolinearity and autocorrelation, in the case of linear models, or overoptimization and noise, in the case of neural networks. This paper proposes filtering the inputs to be employed in the models. To this end, their impact on the forecast will be analysed. A support vector machine will be used to this end, in order to characterize both inputs (indicators and oscillators) and output (market trend). Doing this, it can be assessed whether the relationship between the different inputs and the market trend offers relevant information regarding the contribution of the inputs in the prediction process and whether this contribution remains constant over time. Those inputs will be selected, which obtain more stable forecasts in order to obtain more consistent predictions.
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Piccardo, G., F. Tubino et A. Luongo. « On the effect of mechanical non-linearities on vortex-induced lock-in vibrations ». Mathematics and Mechanics of Solids 22, no 10 (16 juin 2016) : 1922–35. http://dx.doi.org/10.1177/1081286516649991.
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Vortex-induced vibrations at lock-in conditions are modeled through generalized van der Pol-Duffing oscillators endowed with frequency-dependent coefficients, taking inspiration from fluid-elastic models. Accordingly, it is found that the limit-cycle amplitude and the non-linear frequency are mutually dependent (feedback effect), differently from the classic oscillator behavior. Consequently, the mechanical non-linearities, which are often believed to be unimportant, do affect the amplitude of motion. Examples concerning an ideal one degree-of-freedom van der Pol-Duffing oscillator and a two degree-of-freedom model, coarsely representative of a tower building, confirm the importance of this approach also from a technical point of view. Thus, non-linear geometric terms and modal interaction (even in non-resonant cases) can lead to non-negligible modifications of purely aeroelastic problems.
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Joubert, D. J., et A. F. F. Mason. « Investment basics XXIV—Technical analyses part 2 Moving Averages and Momentum Oscillators ». Investment Analysts Journal 20, no 34 (mars 1991) : 49. http://dx.doi.org/10.1080/10293523.1991.11082302.
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Dumbrajs, O., et G. S. Nusinovich. « Effect of technical noise on radiation linewidth in free-running gyrotron oscillators ». Physics of Plasmas 4, no 5 (mai 1997) : 1413–23. http://dx.doi.org/10.1063/1.872345.
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Egorov, N. M., V. I. Ponomarenko, I. V. Sysoev et M. V. Sysoeva. « Simulation of Epileptiform Activity Using Network of Neuron-Like Radio Technical Oscillators ». Technical Physics 66, no 3 (mars 2021) : 505–14. http://dx.doi.org/10.1134/s1063784221030063.
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Górska, Anna, et Monika Krawiec. « CAN INDIVIDUAL INVESTORS BENEFIT FROM TECHNICAL ANALYSIS IN MARKETS OF SOFT COMMODITIES ? EMPIRICAL STUDY FOR 2010–2018 ». Acta Scientiarum Polonorum. Oeconomia 19, no 2 (26 juin 2020) : 25–32. http://dx.doi.org/10.22630/aspe.2020.19.2.14.
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After the 2008 financial crisis, many investors diversified their portfolios with different commodities, including the so-called softs. This paper aims to answer the question of whether individual investors can benefit from technical analysis on soft commodity markets. The empirical study is based on daily quotations of six soft commodities: coffee, cocoa, sugar, cotton, rubber and frozen concentrated orange juice from 2010 to 2018, and investigates the profitability of applying indicators and oscillators based on moving averages with different length. The results show that the application of five-day simple and weighted moving averages and momentum oscillators was most effective, providing positive returns in five out of six soft commodities markets.
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Wei Zhou, Hai Wang, Hui Zhou, Jianning Gao et Lina Bai. « The technical development of crystals and oscillators in China and their market situation ». IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 53, no 1 (janvier 2006) : 30–33. http://dx.doi.org/10.1109/tuffc.2006.1588388.
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POPOV, I. P. « MULTI–INERT OSCILLATORY MECHANISM ». Fundamental and Applied Problems of Engineering and Technology 2 (2020) : 19–25. http://dx.doi.org/10.33979/2073-7408-2020-340-2-19-25.
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A mechanical oscillatory system with homogeneous elements, namely, with n massive loads (multi– inert oscillator), is considered. The possibility of the appearance of free harmonic oscillations of loads in such a system is shown. Unlike the classical spring pendulum, the oscillations of which are due to the mutual conversion of the kinetic energy of the load into the potential energy of the spring, in a multi–inert oscillator, the oscillations are due to the mutual conversion of only the kinetic energies of the goods. In this case, the acceleration of some loads occurs due to the braking of others. A feature of the multi–inert oscillator is that its free oscillation frequency is not fixed and is determined mainly by the initial conditions. This feature can be very useful for technical applications, for example, for self–neutralization of mechanical reactive (inertial) power in oscillatory systems.
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Natsiavas, S., et H. Gonzalez. « Vibration of Harmonically Excited Oscillators With Asymmetric Constraints ». Journal of Applied Mechanics 59, no 2S (1 juin 1992) : S284—S290. http://dx.doi.org/10.1115/1.2899502.
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investigation is carried out for a class of piecewise linear oscillators with asymmetric characteristics. The damping and restoring forces are general trilinear functions of the system velocity and displacement, respectively, while the excitation is harmonic in time. First, an analysis is presented which determines harmonic and subharmonic steady-state response. Then, a special formulation is employed in examining the stability of located periodic motions. Finally, numerical results are presented for several representative sets of the system parameters. Effects of asymmetries in the response due to unequal gaps as well as unequal stiffness and damping coefficients are analyzed in detail. Asymmetric response of a system with symmetric technical characteristics is also investigated. The behavior of the systems examined resembles response of similar nonlinear systems with continuous characteristics, like the response of the Duffing and van der Pol oscillators. Complicated nonperiodic response is also encountered and analyzed.
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Savelkaev, Sergei V., Nadezhda A. Vikhareva et Natalia V. Chekotun. « METHOD OF COMPLEX REFLECTION PARAMETERS MEASUREMENT OF TRANSISTOR LOADS USING A SIMULATOR-ANALYZER OF MICROWAVE AMPLIFIERS AND OSCILLATORS ». Vestnik SSUGT (Siberian State University of Geosystems and Technologies) 26, no 1 (2021) : 150–62. http://dx.doi.org/10.33764/2411-1759-2021-26-1-150-162.
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The article considers a simulator/analyzer that provides simulation modeling of microwave ampli-fiers and oscillators in accordance with their technical specifications, followed by the measurement of complex load reflection coefficients of the active component of these devices for their design. It also considers a method of measurement of these parameters and a method of calibration of the simula-tor/analyzer providing transfer of measurement results from the coaxial measuring line of the simula-tor-analyzer to the microstrip line. In addition, the article considers a method for analyzing the stability of the active component in the space of complex reflection coefficients of its loads, which facilitates their selection in the simulation of amplifiers and oscillators.
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Kryuchkov, I. V., M. I. Noniashvili, A. I. Skachkova et A. A. Filatov. « EXPERIMENTAL RESULTS OF SOFTWARE ALGORITHMIC SYNCHRONIZATION OF DISTRIBUTED RADIO SYSTEM WITH MOBILE CARRIERS ». Journal of the Russian Universities. Radioelectronics, no 2 (24 avril 2019) : 44–52. http://dx.doi.org/10.32603/1993-8985-2019-22-2-44-52.
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Introduction. One of the classes of modern radio engineering systems are systems with spatial diversity of transmitting, receiving or transceiving elements. In such systems, an increase of the information content is achieved by signal coprocessing ensuring synchronization in time and phase of the carrier oscillation. Currently, the researchers do not pay enough attention to the requirements for the accuracy of synchronization of distributed systems of different applications, as well as simple and affordable ways to synchronize them.Objective. The paper main objective is the search for technical solutions for clock and phase synchronization without atomic frequency standards and external sources of coordinate-time information.Methods and materials. The paper considers a distributed radio engineering system with non-rigid structure. Each element of the system has reference signal from its own crystal oscillator. The oscillators are not physically aligned. The phases of their oscillations are periodically compared by the method of two-way transmission of synchronizing signals (from one element to another and vice versa). The synchronization technique (software algorithmic approach) is reduced to the coprocessing signal correction according to estimated frequency (phase) drifts. The testing of the proposed technical solution is presented on a hardware model consisting of ten receiving and transmitting modules.Results. The experiment showed that RMS of synchronization errors does not exceeded 12 degrees by phase (for VHF), or 0.2 ns by time. These results are acquired for spatial diversity up to several hundred meters, mutual speed of the modules up to several meters per second and may be extended for higher frequencies (in particular, UHF).Conclusion. The paper proposes a method of multilateral propagation to synchronize distributed radioengineering systems. Combined with software algorithmic technique this method enables to obtain synchronization accuracy in real-time sufficient for coherent diversity technique.
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Bradic-Martinovic, Aleksandra. « Stock market prediction using technical analysis ». Ekonomski anali 51, no 170 (2006) : 125–46. http://dx.doi.org/10.2298/eka0670125b.
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Technical analysis (TA) is a form of analyzing market encompassing supply and demand of securities according to the study of their prices and trading volume. Using the appropriate methods, TA aims to identify price movements in the stock market, futures or currencies. In short, TA analysis is the process by which "future price movements are formulated according to the price history". TA originates from the work of Charles Dow and his conclusions about the global behavior of the market, as well as from Elliot Wave Theory. Dow did not regard its theory as a tool for stock market movement prediction, nor as a guide for investors, but as a kind of barometer of general market movements. The term TA methods encompasses all the methods used in tracking prices aiming to clearly predict future events. Many different methods, mainly statistical, are used in technical analysis, the most popular ones being: establishing and following trends using moving average, recognizing price momentum, calculating indicators and oscillators, as well as cycle analysis (structure indicators). It is also necessary to point out that TA is not a science in the true meaning of the term, and that methods it uses frequently deviate from the conventional manner of their use. The main advantage of these methods is their relative ease of use, aiming to give as clear picture as possible of price movements, while at the same time avoiding the use of complicated and complex mathematical methods. The reason for this is simple and is reflected in the dynamics of financial markets, where changes occur during short periods of time and where prompt decision-making is of vital importance.
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Petitot, Jean. « The problems of cognitive dynamical models ». Behavioral and Brain Sciences 18, no 4 (décembre 1995) : 640. http://dx.doi.org/10.1017/s0140525x00040322.
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AbstractAmit's “Attractor Neural Network” perspective on cognition raises difficult technical problems already met by prior dynamical models. This commentary sketches briefly some of them concerning the internal topological structure of attractors, the constituency problem, the possibility of activating simultaneously several attractors, and the different kinds of dynamical structures one can use to model brain activity: point attractors, strange attractors, synchronized arrays of oscillators, synfire chains, and so forth.
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Prasetyo, Priyo, Nur Laely et Heri Subagyo. « Analisis Komparatif Penggunaan Metode Stochastic, Moving Average Dan MACD Dalam Mendapatkan Keuntungan Optimal Dan Syar’i (Study Pada Jakarta Islamic Index 2016 – 2018) ». JIMEK : Jurnal Ilmiah Mahasiswa Ekonomi 2, no 1 (16 juillet 2019) : 52. http://dx.doi.org/10.30737/jimek.v2i1.414.
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The purpose of this study is to make a decision when it is appropriate to buy and sell shares in the Jakarta Islamic Index by using technical analysis or other stochastic oscillators, moving averages and MACD. This research is descriptive qualitative research. The population of this study is the Jakarta Islamic Index. The period of January 2016 - December 2018, by taking samples from shares listed on the Jakarta Islamic Index (JII). Sampling is done by purposive sampling technique. The research location is the shares listed on the Jakarta Islamic Index using Chart Nexsus software. Data analysis using technical analysis using three indicators, namely stochastic oscillator, moving average and MACD. Based on the results of the research of the three stochastic oscillator indicators, the moving average and MACD that the one that generates greater profit is using MACD. The right moment in using MACD is if the MACD line cuts the signal line from the bottom up or Golden Cross. And give a sell signal if the MACD line cuts the signal line from top to bottom or Death Cross. Tujuan penelitian ini yaitu untuk mengambil keputusan saat yang tepat untuk jual dan beli saham pada Jakarta Islamic Index dengan menggunakan analisis teknikal atara lain stochastic oscillator, moving average dan MACD. Penelitian ini adalah penelitian kualitatif deskriptif. Populasi penelitian ini yaitu pada Jakarta Islamic Index. Periode Januari 2016 – Desember 2018, dengan mengambil sampel dari saham yang terdaftar pada Jakarta Islamic Index (JII). Penarikan sampel dilakukan dengan teknik purposive sampling. Lokasi penelitian pada saham yang terdaftar di Jakarta Islamic Index dengan menggunakan software Chart Nexsus. Analisis data dengan menggunakan analisis teknikal dengan menggunakan tiga indikator yaitu stochastic oscillator, moving average dan MACD. Berdasarkan hasil penelitian dari ketiga indikator stochastic oscillator, moving average dan MACD bahwasannya yang menghasilkan profit lebih besar adalah dengan menggunakan MACD. Momen yang tepat dalam menggunakan MACD adalah bila garis MACD memotong garis sinyal dari bawah ke atas atau Golden Cross. Dan memberi sinyal jual bila garis MACD memotong garis sinyal dari atas ke bawah atau Death Cross.
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Paluch, Michał, et Lidia Jackowska-Strumiłło. « Hybrid Models Combining Technical and Fractal Analysis with ANN for Short-Term Prediction of Close Values on the Warsaw Stock Exchange ». Applied Sciences 8, no 12 (3 décembre 2018) : 2473. http://dx.doi.org/10.3390/app8122473.
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This paper presents new methods and models for forecasting stock prices and computing hybrid models, combining analytical and neural approaches. First, technical and fractal analyses are conducted and selected stock market indices calculated, such as moving averages and oscillators. Next, on the basis of these indices, an artificial neural network (ANN) provides predictions one day ahead of the closing prices of the assets. New technical analysis indicators using fractal modeling are also proposed. Three kinds of hybrid model with different degrees of fractal analysis were considered. The new hybrid modeling approach was compared to previous ANN-based prediction methods. The results showed that the hybrid model with fractal analysis outperforms other models and is more robust over longer periods of time.
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Hinze, Thomas, Mathias Schumann, Christian Bodenstein, Ines Heiland et Stefan Schuster. « Biochemical Frequency Control by Synchronisation of Coupled Repressilators : AnIn SilicoStudy of Modules for Circadian Clock Systems ». Computational Intelligence and Neuroscience 2011 (2011) : 1–9. http://dx.doi.org/10.1155/2011/262189.
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Exploration of chronobiological systems emerges as a growing research field within bioinformatics focusing on various applications in medicine, agriculture, and material sciences. From a systems biological perspective, the question arises whether biological control systems for regulation of oscillatory signals and their technical counterparts utilise similar mechanisms. If so, modelling approaches and parameterisation adopted from building blocks can help to identify general components for frequency control in circadian clocks along with gaining insight into mechanisms of clock synchronisation to external stimuli like the daily rhythm of sunlight and darkness. Phase-locked loops could be an interesting candidate in this context. Both, biology and engineering, can benefit from a unified view resulting from systems modularisation. In a first experimental study, we analyse a model of coupled repressilators. We demonstrate its ability to synchronise clock signals in a monofrequential manner. Several oscillators initially deviate in phase difference and frequency with respect to explicit reaction and diffusion rates. Accordingly, the duration of the synchronisation process depends on dedicated reaction and diffusion parameters whose settings still lack to be sufficiently captured analytically.
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Fisher, J. R. « Techniques for Coping with Radio Frequency Interference ». Symposium - International Astronomical Union 196 (2001) : 279–87. http://dx.doi.org/10.1017/s0074180900164228.
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As a complement to spectrum management efforts by radio astronomers a number of observatories and research groups around the world have begun looking into technical solutions to the problem of separating weak cosmic radiation from man-made radio signals. Some of the technical research now getting underway includes: high dynamic range receivers, low-noise superconducting filters, passive digital filtering, adaptive filters, adaptive sidelobe nulling, multi-feed correlation of RFI, and various techniques for signal blanking.Increased technical support to spectrum management can also be provided in the form of accurate and statistically significant characterization of the radio environment, empirical and theoretical improvement of over-the-horizon propagation models, and timely measurements of spurious radiation falling in the protected radio astronomy bands.Finally, credibility of our spectrum management effort can only be maintained by making sure that local radiation under the control of our radio observatories is in compliance with the field strength limits of Recommendation ITU-R R.A.769. This requires sensitive radiation measurements and often shielding of digital equipment, microwave ovens, test equipment, local oscillators, etc.
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Filina, O. A., A. N. Tsvetkov, P. P. Pavlov, D. Radu et V. M. Butakov. « Vibration model as a system of coupled oscillators in a direct current electric motor ». E3S Web of Conferences 124 (2019) : 02002. http://dx.doi.org/10.1051/e3sconf/201912402002.
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This article describes a vibration model connected by individual nodes of a DC motor. The purpose of the article is a mathematical model allowing to predict the work of machines with a depreciation resource and search for ways to increase the information content of assessing the functioning of the rolling stock condition without dismantling them. Currently, the operational reliability of the DC motor is reduced after the development of the service life. Study and evaluation of the vibration effect on the brush-collector node. The main components of the DC motor (bearings, electrical brushes) are unrecoverable. Therefore, any interference with their normal operation leads to premature wear of the entire DC motor. Existing methods for life-extending maintain the operational reliability of a DC motor equal or close to the passport data for several years. This model allows vibration diagnostics without dismantling the DC motor and stopping the rolling stock. The mathematical model describes the oscillations of each node of the DC motor in the direction of movement of the rolling stock, showing the excess of the permissible value. After mathematical processing of the results, a machine reliability model under study is obtained (usually in the form of polynomials) as a function of the needed parameters – the influencing factors. Due to this model, pre-detected defects can save on repairs and maintenance in the future. This model is the basis of software for online diagnostics. The proposed model allows providing an objective use of repair and restoration compositions depending on the current technical condition, which will lead to an increase in the service life of the mechanism and savings in operating costs. On the one hand, extending the operating life of a DC motor should produce an economic effect, and on the other hand, technical measures to maintain operational reliability cause an increase in material costs.
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Zhogoleva, Nadiya, et Volodymyr Shcherbak. « Asymptotic evaluation of the state and stiffness of the van der Paul oscillator ». Proceedings of the Institute of Applied Mathematics and Mechanics NAS of Ukraine 33 (27 décembre 2019) : 91–99. http://dx.doi.org/10.37069/1683-4720-2019-33-7.
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In many applications of physics, biology, and other sciences, an approach based on the concept of model equations is used as an approximate model of complex nonlinear processes. The basis of this concept is the provision that a small number of characteristic types movements of simple mathematical models inherent in systems gives the key to understanding and exploring a huge number of different phenomena. With this approach it is a priori assumed that the entire physical diverseness can be represented in the form of fairly simple model equations. It is contributes to a qualitative study of complex systems for various physical nature since basic models individually are well studied, their parameters have a physical interpretation. In particular, it is well known that oscillatory motion of various systems with a stable limit cycle can be modeled by a system consisting of one or more coupled van der Pol oscillators. Such systems are widely represented in various technical devices and in the study and modeling of some biological functions of the body, such as cardiac activity, respiration, locomotor activity, etc. It is considered a typical situation for many practical applications of control theory when the complete state vector of the system is unknown and only some of the functions of the state variables -- the outputs of the system are accessible to measurement. Therefore, the problem of determining in real time the state and parameters of such systems based on the results of measuring the output signals are relevant. One of these inverse control problems, namely, the problem of observability and parameter identification of an model oscillatory system is considered in this article. For observation and identification scheme design the method of invariant relations developed in analytical mechanics is used. Its modification in control problems allows us to synthesize additional relationships between known and unknown quantities of a dynamical system that arise during the observed motion. The method does not involve linearization of the original system and is essentially non-linear. The constructed nonlinear observer provides an asymptotic estimation of unknown parameter and velocity of oscillations.
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Zadorin, A. S., et A. A. Lukina. « A RESONANCE SYSTEM OF AN OPTOELECTRONIC OSCILLATOR BASED ON A TRANSMISSIONTYPE PLANAR OPTICAL DISK MICROCAVITY ». Computer Optics 42, no 1 (30 mars 2018) : 60–66. http://dx.doi.org/10.18287/2412-6179-2018-42-1-60-66.
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It is noted that the best technical characteristics of optoelectronic microwave self-oscillators (OESO) are reached in schemes employing high-Q optical microresonators (OMR) working in the traveling wave modes (TWM). A possibility of using disk OMRs excited by fundamental whispering gallery modes (WGM) has been considered. Multielement coupling devices (CD) for such resonators have been investigated. They are constructed on the basis of planar optical waveguides (POWG) located over the disk resonator surface in a region bounded by the outer and inner caustics of the WGM. Models of this device have been proposed. The corresponding calculations have been provided.
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Lahmiri, Salim. « Entropy-Based Technical Analysis Indicators Selection for International Stock Markets Fluctuations Prediction Using Support Vector Machines ». Fluctuation and Noise Letters 13, no 02 (juin 2014) : 1450013. http://dx.doi.org/10.1142/s0219477514500138.
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Most of works on stock price forecasting are concerned with the problem of predicting its future value. However, forecasting stock price future fluctuation trend could be easier and interesting for traders and investors to maximize profits. The purpose of this study is to predict CAC40, FTSE, NASDAQ and S&P500 price index up and down fluctuations. In particular, it aims to propose a methodology to forecast regime switches in these markets time series to assist traders and investors in decision making. In the first stage, a large set composed of twenty five technical analysis indicators is formed. They fall into four broad categories namely oscillators, stochastic measures, indexes and indicators. Entropy statistic is employed to rank the initial technical analysis indicators. Finally, in the third stage, polynomial-based kernel support vector machines (SVM) are used for predicting CAC40, FTSE, NASDAQ and S&P500 future upward and downward fluctuations. The forecasting results show that the choice of technical analysis indicators used to predict CAC40 and NASDAQ fluctuations depend on the type of risk-aversion and risk-appetite of the investor. For the S&P500 and FTSE, technical analysis indicators used in our study can detect future downshifts with high accuracy. Thus, they are suitable for market analysis and trading by risk-averse investors on these markets.
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LEBIEDZ, D. « EXPLOITING OPTIMAL CONTROL FOR TARGET-ORIENTED MANIPULATION OF (BIO)CHEMICAL SYSTEMS : A MODEL-BASED APPROACH TO SPECIFIC MODIFICATION OF SELF-ORGANIZED DYNAMICS ». International Journal of Modern Physics B 19, no 25 (10 octobre 2005) : 3763–98. http://dx.doi.org/10.1142/s0217979205032498.
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In this paper we review recent progress in the development and application of advanced optimal control methods for target-oriented manipulation of self-organized dynamics in (bio)chemical reaction systems. We discuss results related to nonlinear model-based external control aimed at forcing and stabilization of spatiotemporal pattern formation and specific driving, phase resetting and annihilation of limit cycle oscillators. We refer to both open-loop and feedback optimal control approaches. Optimal control strategies for self-organized systems may be highly beneficial in applications concerned with steering of technical processes in open non-equilibrium systems and specific manipulation of self-organized cellular dynamics in biomedicine.
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Zeh, H. Dieter. « The Strange (Hi)story of Particles and Waves ». Zeitschrift für Naturforschung A 71, no 3 (1 mars 2016) : 195–212. http://dx.doi.org/10.1515/zna-2015-0509.
Texte intégralRésumé :
AbstractThis is an attempt of a non-technical but conceptually consistent presentation of quantum theory in a historical context. While the first part is written for a general readership, Section 5 may appear a bit provocative to some quantum physicists. I argue that the single-particle wave functions of quantum mechanics have to be correctly interpreted as field modes that are “occupied once” (i.e. first excited states of the corresponding quantum oscillators in the case of boson fields). Multiple excitations lead to apparent many-particle wave functions, while the quantum states proper are defined by wave function(al)s on the “configuration” space of fundamental fields, or on another, as yet elusive, fundamental local basis.
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Paluch, Michał, et Lidia Jackowska-Strumiłło. « Prediction of Closing Prices on the Stock Exchange with the Use of Artificial Neural Networks ». Image Processing & ; Communications 17, no 4 (1 décembre 2012) : 275–82. http://dx.doi.org/10.2478/v10248-012-0056-5.
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Abstract Article describes, the use of Artificial Neural Networks (ANN) for predicting values of Stock Exchange shares. Rules of Stock Exchange functioning, principles of technical analysis and the most important stock market indices are described, which support investors, who plan to make transactions. ANN of Multi-Layer Perceptron (MLP) type, and a moving window method are applied. A hybrid method is also proposed, in which time series of CLOSE values as a function of the following trading days are used to stock market indices calculation, such as moving averages and oscillators, which are applied to ANN inputs. Research was conducted for 80 companies, selected from the 1218 companies functioning on Stock Exchange. The achieved maximum error in one day ahead CLOSE value prediction is 1,31%.
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Trembiński, Marek, et Joanna Stawska. « The Effectiveness of the Transaction Systems on the Dax Index ». Finanse i Prawo Finansowe 4, no 28 (31 décembre 2020) : 149–74. http://dx.doi.org/10.18778/2391-6478.4.28.09.
Texte intégralRésumé :
The purpose of the article/hypothesis: The aim of this article is to examine the effectiveness of trading systems built on the basis of technical analysis tools in 2015–2020 on the DAX stock exchange index. Efficiency is understood as generating positive rates of return, taking into account the risk incurred by the investor, as well as achieving better results than passive strategies. Presenting empirical evidence implying the value of technical analysis is a difficult task not only because of a huge number of instruments used on a daily basis, but also due to their almost unlimited possibility to modify parameters and often subjective evaluation.Methodology: The effectiveness of technical analysis tools was tested using selected investment strategies based on oscillators and indicators following the trend. All transactions were carried out on the Meta Trader 4 platform. The analyzed strategies were comprehensively assessed using the portfolio management quality measures, such as the Sharpe measure or the MAR ratio (Managed Account Ratio).Results of the research: The test results confirmed that the application of described investment strategies contributes to the achievement of effective results and, above all, protects the portfolio against a significant loss in the period of strong turmoil on the stock exchange. During the research period, only two strategies (Ichimoku and ETF- Exchange traded fund) would produce negative returns at the worst possible end of the investment. At the best moment, however, the „passive” investment achieved the lowest result. Looking at the final balance at the end of 2019, as many as four systems based on technical analysis were more effective than the „buy and hold” strategy, and at the end of the first quarter of 2020 – all of them. When analyzing the management quality measures, it turned out that taking into account the 21 quarters, the passive strategy had the lowest MAR index. The Sharpe’s measure is also relatively weak compared to the four leading strategies.
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Głogowski, Michał, Przemysław Kubiak, Szymon Szufa, Piotr Piersa, Łukasz Adrian et Mateusz Krukowski. « The Use of the Fourier Series to Analyze the Shaping of Thermodynamic Processes in Heat Engines ». Energies 14, no 8 (20 avril 2021) : 2316. http://dx.doi.org/10.3390/en14082316.
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The article presents the application of the Fourier series to theoretical considerations on the method of maximum temperature control in thermodynamic cycles of internal combustion engines equipped with an additional independent kinematic system. The analysis assumes that the processes are zero-dimensional and the gases consumed in the engine cycles are perfect, simplifying the considerations for temperature control as a function of the two variables, pressure and volume, of which the volume as a geometric quantity can be completely controlled. In view of this fact, a predetermined temperature curve was assumed, ultimately reducing the considerations of specific volume changes, that is to say a kinematic system that could implement these changes. Moreover, in the analysis of volume changes, a cycle not used so far in the description of internal combustion engines was used. In the next step, the cycle was modified using the popular Vibe function, which was replaced in the theoretical cycle by two isochoric and isothermal transformations. Heat exchange was completely omitted in the considerations, in that it is of secondary importance, ultimately bringing the temperature function to the function of one variable, the angle of rotation of the crankshaft. Then, the kinematics was divided into the kinematics of the crank-piston system and the additional system, which was approximated with five words from the Fourier series, which in the technique correspond, for example, to the system of oscillators. At the end of the article we have explained one of the ways of actual technical implementation using a single nonlinear oscillator, the so-called ACC system equivalent to a few words from the mentioned Fourier series.
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García, Fernando, Francisco Guijarro, Javier Oliver et Rima Tamošiūnienė. « HYBRID FUZZY NEURAL NETWORK TO PREDICT PRICE DIRECTION IN THE GERMAN DAX-30 INDEX ». Technological and Economic Development of Economy 24, no 6 (21 novembre 2018) : 2161–78. http://dx.doi.org/10.3846/tede.2018.6394.
Texte intégralRésumé :
Intraday trading rules require accurate information about the future short term market evolution. For that reason, next-day market trend prediction has attracted the attention of both academics and practitioners. This interest has increased in recent years, as different methodologies have been applied to this end. Usually, machine learning techniques are used such as artificial neural networks, support vector machines and decision trees. The input variables of most of the studies are traditional technical indicators which are used by professional traders to implement investment strategies. We analyse if these indicators have predictive power on the German DAX-30 stock index by applying a hybrid fuzzy neural network to predict the one-day ahead direction of index. We implement different models depending on whether all the indicators and oscillators are used as inputs, or if a linear combination of them obtained through a factor analysis is used instead. In order to guarantee for the robustness of the results, we train and apply the HyFIS models on randomly selected subsamples 10,000 times. The results show that the reduction of the dimension through the factorial analysis generates more profitable and less risky strategies.
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García, Fernando, Francisco Guijarro, Javier Oliver et Rima Tamošiūnienė. « HYBRID FUZZY NEURAL NETWORK TO PREDICT PRICE DIRECTION IN THE GERMAN DAX-30 INDEX ». Technological and Economic Development of Economy 24, no 6 (21 novembre 2018) : 2161–78. http://dx.doi.org/10.3846/10.3846/tede.2018.6394.
Texte intégralRésumé :
Intraday trading rules require accurate information about the future short term market evolution. For that reason, next-day market trend prediction has attracted the attention of both academics and practitioners. This interest has increased in recent years, as different methodologies have been applied to this end. Usually, machine learning techniques are used such as artificial neural networks, support vector machines and decision trees. The input variables of most of the studies are traditional technical indicators which are used by professional traders to implement investment strategies. We analyse if these indicators have predictive power on the German DAX-30 stock index by applying a hybrid fuzzy neural network to predict the one-day ahead direction of index. We implement different models depending on whether all the indicators and oscillators are used as inputs, or if a linear combination of them obtained through a factor analysis is used instead. In order to guarantee for the robustness of the results, we train and apply the HyFIS models on randomly selected subsamples 10,000 times. The results show that the reduction of the dimension through the factorial analysis generates more profitable and less risky strategies.
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Davis, John, et Bernard Lovell. « Robert Hanbury Brown. 31 August 1916 – 16 January 2002 Elected FRS 1960 ». Biographical Memoirs of Fellows of the Royal Society 49 (janvier 2003) : 83–106. http://dx.doi.org/10.1098/rsbm.2003.0005.
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Robert Hanbury Brown was born on 31 August 1916 in Aruvankadu, Nilgiri Hills, South India; he was the son of an Officer in the Indian Army, Col. Basil Hanbury Brown, and of Joyce Blaker. From the age of 3 years Hanbury was educated in England, initially at a School in Bexhill and then from the ages of 8 to 14 years at the Cottesmore Preparatory School in Hove, Sussex. In 1930 he entered Tonbridge School as a Judde scholar in classics. Hanbury's interests turned to science and technology, particularly electrical engineering, and after two years he decided that he would seek more appropriate education in a technical college. His decision was accelerated by the fact that after the divorce of his parents his mother had married Jack Lloyd, a wealthy stockbroker, who in 1932 vanished with all his money and thus Hanbury felt he should seek a career that would lead to his financial independence. For these reasons Hanbury decided to take an engineering course at Brighton Technical College studying for an external degree in the University of London. At the age of 19 he graduated with a first-class honours BSc, taking advanced electrical engineering and telegraphy and telephony. He then obtained a grant from East Sussex and in 1935 joined the postgraduate department at the City & Guilds, Imperial College. In 1936 he obtained the Diploma of Imperial College (DIC) for a thesis on oscillators He intended to continue his course for a PhD but a major turning point in his career occurred when he was interviewed during his first postgraduate year by Sir Henry Tizard FRS, Rector of Imperial College. Hanbury explained to Tizard that he was following up some original work by Van der Pol on oscillator circuits without inductance and hoped, ultimately, to combine an interest in radio with flying. In fact, Tizard had already challenged him about the amount of time he spent flying with the University of London Air Squadron. Tizard told Hanbury to see him again in a year's time and that he might then have a job for him. In fact, within three months Tizard accosted Hanbury and said he had an interesting research project in the Air Ministry for him. After an interview by R.A. (later Sir Robert) Watson-Watt (FRS 1941), Hanbury was offered a post at the Radio Research Board in Slough. His visit to Slough was brief; he was soon told to report to Bawdsey Manor in Suffolk, which he did on 15 August 1936. Thereby, unaware of what Tizard had in mind for him, Hanbury's career as one of the pioneers of radar began.
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Vincent, Kylie A. « Triggered infrared spectroscopy for investigating metalloprotein chemistry ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 368, no 1924 (13 août 2010) : 3713–31. http://dx.doi.org/10.1098/rsta.2010.0055.
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Recent developments in infrared (IR) spectroscopic time resolution, sensitivity and sample manipulation make this technique a powerful addition to the suite of complementary approaches for the study of time-resolved chemistry at metal centres within proteins. Application of IR spectroscopy to proteins has often targeted the amide bands as probes for gross structural change. This article focuses on the possibilities arising from recent IR technical developments for studies that monitor localized vibrational oscillators in proteins—native or exogenous ligands such as NO, CO, SCN − or CN − , or genetically or chemically introduced probes with IR-active vibrations. These report on the electronic and coordination state of metals, the kinetics, intermediates and reaction pathways of ligand release, hydrogen-bonding interactions between the protein and IR probe, and the electrostatic character of sites in a protein. Metalloprotein reactions can be triggered by light/dark transitions, an electrochemical step, a change in solute composition or equilibration with a new gas atmosphere, and spectra can be obtained over a range of time domains as far as the sub-picosecond level. We can expect to see IR spectroscopy exploited, alongside other spectroscopies, and crystallography, to elucidate reactions of a wide range of metalloprotein chemistry with relevance to cell metabolism, health and energy catalysis.
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Plint, M. A., et A. J. Martyr. « Technical Note : Some limitations of the chassis dynamometer in vehicle simulation ». Proceedings of the Institution of Mechanical Engineers, Part D : Journal of Automobile Engineering 215, no 3 (1 mars 2001) : 431–37. http://dx.doi.org/10.1243/0954407011525647.
Texte intégralRésumé :
The chassis dynamometer is the standard tool for legislatively prescribed emission tests. For emission testing and many other vehicle test purposes the dynamic response is an adequate approximation to ‘on road’ conditions. This is not necessarily true if the requirement is to study vehicle driveline dynamics. The present analysis arose from two quite separate requirements to study driveline oscillations and ‘judder’ using chassis dynamometers of the same eVective inertia as the vehicle. During the studies by the authors it became clear that the dynamics of the vehicle-dynamometer combination diVer in important respects from those of a vehicle on the road. As the eVective inertia of the dynamometer falls the natural frequency of the engine-driveline-vehicle system rises while the oscillatory energy imparted to the vehicle falls rapidly. For reasonably accurate simulation of driveline vibration the roll inertia should be some five times that of the vehicle. It is shown that electrical simulation of inertia, as employed in most modern chassis dynamometers, is unsatisfactory where oscillatory phenomena are being studied.
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Nandakumar, K., et Anindya Chatterjee. « Higher-Order Pseudoaveraging via Harmonic Balance for Strongly Nonlinear Oscillations ». Journal of Vibration and Acoustics 127, no 4 (26 septembre 2004) : 416–19. http://dx.doi.org/10.1115/1.1924639.
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Some strongly nonlinear conservative oscillators, on slight perturbation, can be studied via averaging of elliptic functions. These and many other oscillations allow harmonic balance-based averaging (HBBA), recently developed as an approximate first-order calculation. Here, we extend HBBA to higher orders. Unlike the usual higher-order averaging for weakly nonlinear oscillations, here both the dynamic variable and time are averaged with respect to an auxiliary variable. Since the harmonic balance approximations introduce technically O(1) errors at each order, the higher-order results are not strictly asymptotic. Nevertheless, as we show with examples, for reasonable values of the small expansion parameter, excellent approximations are obtained.
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Rossouw, Willem, et Jacobus Young. « Effectiveness of the management of price risk methodologies for the corn market based on trading signals ». Risk Governance and Control : Financial Markets and Institutions 3, no 1 (2013) : 7–17. http://dx.doi.org/10.22495/rgcv3i1art1.
Texte intégralRésumé :
Corn production is scattered geographically over various continents, but most of it is grown in the United States. As such, the world price of corn futures contracts is largely dominated by North American corn prices as traded on the Chicago Board of Trade. In recent years, this market has been characterised by an increase in price volatility and magnitude of price movement as a result of decreasing stock levels. The development and implementation of an effective and successful derivative price risk management strategy based on the Chicago Board of Trade corn futures contract will therefore be of inestimable value to market stakeholders worldwide. The research focused on the efficient market hypothesis and the possibility of contesting this phenomenon through an application of a derivative price risk management methodology. The methodology is based on a combination of an analysis of market trends and technical oscillators with the objective of generating returns superior to that of a market benchmark. The study found that market participants are currently unable to exploit price movement in a manner which results in returns that contest the notion of efficient markets. The methodology proposed, however, does allow the user to consistently achieve returns superior to that of a predetermined market benchmark. The benchmark price for the purposes of this study was the average price offered by the market over the contract lifetime, and as such, the efficient market hypothesis was successfully contested.
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Zhuravlev, V. Ph. « Van der Pol Oscillator. Technical Applications ». Mechanics of Solids 55, no 1 (janvier 2020) : 132–37. http://dx.doi.org/10.3103/s0025654420010203.
Texte intégral
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Repin, Sergei, Roman Litvin, Victor Kuzmichev et Ivan Vorontsov. « AUTOMOTIVE SHOCK ABSORBERS’ APPLICABILITY FOR DAMPING RESONANT OSCILLATIONS IN CONSTRUCTION MACHINES ». Architecture and Engineering 6, no 1 (2021) : 81–87. http://dx.doi.org/10.23968/2500-0055-2021-6-1-81-87.
Texte intégralRésumé :
Introduction: Many vibration transport and technological machines (VTTM) such as conveyors, screens, crushers, etc. operate in a high-frequency mode, or above resonance. Resonance occurs during machine start and slowdown, resulting in sharply rising values of the amplitude and velocity of oscillations. Resonance affects VTTMs adversely due to increased dynamic loads reducing machinery operating life and reliability and causing the noise. Purpose of the study: We aim to provide a theoretical substantiation for the possibility to apply automotive shock absorbers to VTTM oscillatory process control and develop an example of practical implementation for such a device. Methods: The method of controlling oscillatory processes in VTTMs lies in the use of dual-mode shock absorbers. In the operating mode, shock absorbers offer minimum resistance to motion. In the resonance mode, resistance increases, therefore, the amplitude decreases to a predetermined value. Results: We simulate the VTTM oscillatory process in order to determine the characteristics of a damping device, which ensures the suppression of resonant oscillations but does not affect the vibration operating process. We propose a new technical device implementing the required oscillation characteristics. The device is made in the form of a hydro-pneumatic shock absorber, similar to automotive shock absorbers in terms of design. Such a design makes it possible to offer slight damping of the machine’s useful (operating) vibration, but, at the same time, damping increases significantly in the case of resonant amplitudes. The originality of our study lies in the development of a new type of hydraulic shock absorber, for which a utility model patent has been obtained. The scientific novelty of the study is in the mathematical description of oscillation damping with the new shock absorber, in the development of software for oscillatory process analysis according to the developed mathematical model, and in the results of computer simulation for shock absorber operation.
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Antal, Andrea, et Christoph S. Herrmann. « Transcranial Alternating Current and Random Noise Stimulation : Possible Mechanisms ». Neural Plasticity 2016 (2016) : 1–12. http://dx.doi.org/10.1155/2016/3616807.
Texte intégralRésumé :
Background. Transcranial alternating current stimulation (tACS) is a relatively recent method suited to noninvasively modulate brain oscillations. Technically the method is similar but not identical to transcranial direct current stimulation (tDCS). While decades of research in animals and humans has revealed the main physiological mechanisms of tDCS, less is known about the physiological mechanisms of tACS.Method. Here, we review recent interdisciplinary research that has furthered our understanding of how tACS affects brain oscillations and by what means transcranial random noise stimulation (tRNS) that is a special form of tACS can modulate cortical functions.Results. Animal experiments have demonstrated in what way neurons react to invasively and transcranially applied alternating currents. Such findings are further supported by neural network simulations and knowledge from physics on entraining physical oscillators in the human brain. As a result, fine-grained models of the human skull and brain allow the prediction of the exact pattern of current flow during tDCS and tACS. Finally, recent studies on human physiology and behavior complete the picture of noninvasive modulation of brain oscillations.Conclusion. In future, the methods may be applicable in therapy of neurological and psychiatric disorders that are due to malfunctioning brain oscillations.
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Politansky, R. L., Z. M. Nytrebych, R. I. Petryshyn, I. T. Kogut, O. M. Malanchuk et M. V. Vistak. « Simulation of the Propagation of Electromagnetic Oscillations by the Method of the Modified Equation of the Telegraph Line ». Physics and Chemistry of Solid State 22, no 1 (18 mars 2021) : 168–74. http://dx.doi.org/10.15330/pcss.22.1.168-174.
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The article considers the physical processes associated with the propagation of electromagnetic oscillations in a long line, the size of which is the same or slightly greater than the length of the electromagnetic wave (not more than ten times). As a research method, the differential-symbolic method is used, which is applied to the modified equation of the telegraph line. The boundary conditions for the two-point problem as well as additional parameters that are coefficients for the first derivatives in terms of coordinate and time in comparison with the classical equation of the telegraph line are considered as parameters for controlling the process of propagation of electromagnetic oscillations. Based on the differential-symbolic method, the boundary conditions of the two-point problem are found, under which the most characteristic oscillatory processes are realized in a long line. Based on the research, it is possible to draw conclusions about the effectiveness of analytical methods for the analysis of specific technical objects and control of the processes that take place in them.
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Hudson, H. S. « Asteroseismology : The Impact of Solar Space Observations ». International Astronomical Union Colloquium 137 (1993) : 43–50. http://dx.doi.org/10.1017/s0252921100017413.
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AbstractObservations from space relevant to solar global properties (oscillations, magnetic activity, etc.) are helpful both scientifically and technically in preparing for stellar observations. This paper summarizes the results from the main previous experiments (ACRIM, SOUP, and IPHIR), and also give an initial technical report from the SXT instrument on board Yohkoh, launched in August 1991. The solar observations to date demonstrate the existence of several mechanisms for low–level variability: spots, faculae, the photospheric network, granulation, and p–mode oscillations. The observations of oscillations have been particularly helpful in setting limits on solar interior rotation. In addition to the solar processes, stars of other types may have different mechanisms of variability. These may include the analogues of coronal holes or solar flares, modes of oscillation not detected in the Sun, collisions with small bodies, duplicity, and probably mechanisms not invented yet but related in interesting ways to stellar convection and magnetism.
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SOLDATENKO, L. S., et O. V. HORNISHNYI. « CLARIFICATION OF THE METHODS USED FOR CALCULATING POWER OF SIEVE SEPARATORS ». Grain Products and Mixed Fodder’s 18, no 4 (17 janvier 2019) : 47–50. http://dx.doi.org/10.15673/gpmf.v18i4.1197.
Texte intégralRésumé :
Calculation of sieve separators power is usually done during their development. The goal of such calculations is to determine the power of driven electric motors. The imperfection of existing methods for calculating power of some types of sieve separators makes developers to use indicative methods to determine the gear power. For example, it is done using the method of specific energy consumption or the comparison method with parameters of similar equipment. These methods provide only indicative results, that is why the power of the installed electric motors sometimes even exceeds the needed one, so in such way it worsens technical and economic factors of the equipment. The methods for calculating power of flat-sieve separators moving progressive and invers or circular progressive have clearly determined sense and consider all energy consumptions of separators’ engine. The goal of the calculation of technological equipment and sieve separators in particular is to define the power of the electric motors. The imperfection of existing methods for calculating power leads to use in some machines of high power engines which selection is based on indicative calculations, for example, using a method of specific energy consumption or comparing with analogues. As the calculating methods depend on the law of working parts movement and their engine each example considered separately. In the calculation of the power of separators with flat sieve which are moving oscillatory the effective power required by the engine of sieve bodies equal to the sum of the average power required to drive the oscillatory moving mass; the average power that is needed for product overclocking; the average power required to overcome the friction force of the product in the sieve; the average power used to deform the suspension; the average power need to overcome the drag of the air environment. The current value of the power which is need to drive the oscillatory construction elements is determined considering the total value of oscillatory bodies mass; the weight and the amount of sieve bodies; the product weight on the bodies sieves; the weight of the oscillator; the frame weight. During a circular progressive movement of sieve bodies the power which is need to overclock the product mass on the sieve which are moving reciprocally is almost equal to zero, because the product is moving with stops during the all-time being on the sieve. This also refers to the movement of the product on the barrel sieves which are rotating, where parts change the direction of movement while they are slipping down and get accelerated again. The acceleration power in the separators with circled progressive motion of the sieves is equal to the kinetic energy of its circle oscillations. To provide the relative motion of the parts on the horizontal sieve surface which is making a circled progressive motion it is necessary that the difference between the centred inertial force and friction force to be more than zero.
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Testoyedov, Nikolay, Vladimir Berns, Egor Zhukov, Evgenii Lysenko et Pavel Lakiza. « Control of gaps in technical structures during ground vibration testing ». Metal Working and Material Science 23, no 2 (10 juin 2021) : 40–53. http://dx.doi.org/10.17212/1994-6309-2021-23.2-40-53.
Texte intégralRésumé :
Introduction. A fair number of technical structures have gaps (backlashes) which can be contingently divided into two types. One of them is the gaps in connections between substructures which are introduced so that the connections may operate correctly. Sizes of such gaps are usually normalized. Another type is the backlashes which occur during operation. Due to the normalized gaps usually expand while operating, both of the types may lead to increased loading and wear of mechanical parts, an alteration in dynamical characteristics and a deterioration in a technical state of mechanical structures. It explains the necessity to control the gaps. When the ground vibration testing of the structures is performed, it seems appropriate to use these tests to detect such gaps. Research Objective: developing the method to control the gaps in the technical structures during the ground vibration testing based on distortions of portraits of forced oscillations. Research Technique. The steady-state forced oscillations of the technical structures, which were measured by acceleration sensors, are excited by means of shakers. The sensor signals are represented as the portraits: the vertical scanning is proportional to the signal and the horizontal scanning – to its first harmonic with the phase shift of π/2. In case of a linear system, the portraits are circles. The presence of the gaps distorts the portraits of oscillations specifically. To estimate the distortions numerically, the first harmonic is subtracted from the Fourier series of the portrait of oscillations, the absolute maximum of the residue is calculated over the oscillation period and used subsequently as the distortion parameter Ψ. The value of the parameter Ψ is normalized and denoted as ξ. The ξ distributions are plotted on controlled objects. The locations of the gaps are determined through the positions of the local maxima of the distortions. While calculating the parameter ξ, the two types of normalization, which were conditionally named the global and local ones, are being used. In case of the global normalization, the value of Ψ is related to the amplitude of the first harmonic at the control point of the structure. The local normalization means that the magnitude of Ψ is related to the amplitude of the first harmonic of the sensor where that parameter was previously calculated. The global normalization is required to analyze the distortion distribution of the portraits of oscillations of the entire technical structure. The local normalization of the distortions of the portraits of oscillations is utilized to establish the locations of the gaps in the mechanical parts and structural connections. The ground vibration tests were carried out via Test.Lab software. The subprogram is integrated into the software interface in order to analyze the portraits of oscillations. It enabled one to calculate the distortions of the portraits of oscillations, plot the distortion distributions of the structure and save it for further use. It allowed one to control the gaps during vibration strength tests, as well as while the structures being used, by means of comparing the distortion distributions of the parameter ξ related to different states of the structure. Additionally, the plotting of the distortion distributions of the portraits of oscillations for each structural component is added to the subprogram so as to control the defects subsequently. Not only the locations of the gaps are determined in the force-displacement application systems but also the equation is given to calculate its magnitudes. The practical recommendations on using that equation are presented. Results and Discussion. The possibility of detecting the gaps by the distortions of the portraits of oscillations is illustrated with the example of the diagnostics of the layout of the control wiring and the airplanes during the ground vibration testing as well as the open-type spacecraft structures. It is shown that the developed method enables one to detect all the gaps in the testing object which distort the portraits of oscillations.
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Lanets, Oleksii, Volodymyr Borovets, Pavlo Maistruk et Iryna Derevenko. « SUBSTANTIATION OF RATIONAL SELECTION OF MOTOR-VIBRATORS VIBRATION MACHINES ». Vibrations in engineering and technology, no 3(94) (26 novembre 2019) : 24–32. http://dx.doi.org/10.37128/2306-8744-2019-3-4.
Texte intégralRésumé :
An integral component in the calculation of vibration machines is the establishment of drive power necessary to set in motion an oscillating system with specified characteristics. However, difficulties often arise at this stage. The inertial characteristics of the drive directly affect the power consumption. Therefore, when calculating it, you must already know the size of the drive, which is still unknown, since it is only being installed. This question is especially relevant for low-frequency oscillatory systems with an inertial drive, in which the inertial parameters of the drive are proportional to the masses of the oscillatory systems. In such oscillatory systems, ignoring the mass of the drive when setting the consumed power to set the mechanical oscillating system in motion can lead to the fact that the vibrating machine will not be able to provide the expected (calculated) technical and technological parameters, since the massive drive oscillates with the whole system, will take on its own propulsion a significant proportion of the energy. The article justifies the analytical relation¬ships for calculating the power of vibration machines with inertial drive, taking into account the mass of vibrator motors. For this, systems of equations are solved that interconnect analytical expressions for calculating the powers necessary to bring the oscillatory systems into motion, taking into account the mass of vibrator motors. The solution to such systems is the value of the required drive power (vibrator motors) and its mass, which is already consistent with the masses of unified vibrator motors produced by manufacturers. The obtained analytical dependences make it quite easy to determine the power of the drives in one-, two- and trimass oscillation systems of vibration machines with an inertial drive. Using the formulas obtained in the article, it is possible to precisely establish the necessary drive power to set the oscillatory system in motion and uniquely select the mass of the vibrator motor.
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Haiko, Hennadii, Oleksandr Zhivkov et Lubov Pyha. « Application of resonant oscillatory systems for the seafloor gas hydrates development ». E3S Web of Conferences 230 (2021) : 01020. http://dx.doi.org/10.1051/e3sconf/202123001020.
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The prospects for the gas recovery from bottom gas hydrates are studied, and the necessity for the formation of an innovation environment and practical steps for conducting industrial experiments are formulated. The promising methods of shielded development of seafloor gas hydrate deposits are analyzed and the technical problems of their improvement are revealed. The possibilities of using resonant oscillatory systems for the shielded development of bottom gas hydrates are studied, in particular, a Helmholtz flow-excited resonator. The expediency of using high-quality oscillations of the “rotator” type has been substantiated in order to facilitate controlled gas hydrates dissociation over large areas of a gas hydrate field and to counteract the formation of new gas hydrates in the fractures of hydraulic reservoir fracturing. A method has been developed of gas recovery from bottom methane hydrates using a resonator device, which significantly reduces the energy consumption for the gas hydrates dissociation and contributes to the technological processes control.
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Omelyanov, Oleg, et Mykhailo Zamriі. « DIRECTIONS OF IMPROVING THE EFFICIENCY OF VIBRATION TECHNOLOGICAL MACHINES ». Vibrations in engineering and technology, no 4(99) (18 décembre 2020) : 49–58. http://dx.doi.org/10.37128/2306-8744-2020-4-6.
Texte intégralRésumé :
The article considers the directions of increasing the efficiency of vibrating technological machines. The processing of information on the development of vibration technologies is quite diverse and is represented by numerous scientific and technical developments related to improving the efficiency of vibration machines and ensuring the reliability of their work. The analytical basis for previous research in the creation of new technology are mathematical models that reflect the properties of mechanical oscillatory systems with several degrees of freedom, which perform small oscillations under the action of a system of periodic external perturbations that create vibration fields of one configuration. The dynamic properties of the working bodies of machines in a detailed form are revealed as the distribution of the amplitudes of oscillations of the points of the working bodies. In many cases, this distribution is linear, which is due to the manifestations of the properties of the simplest movements of the working bodies. Approaches are proposed in which the possible structural mathematical modeling is realized on the idea that a linear mechanical oscillatory system with concentrated parameters and several degrees of freedom can be compared with the structural scheme of the automatic control system. Particular attention is paid to the study and evaluation of the possibility of new dynamic effects associated with the simultaneous action of several working bodies of machines, as well as - modes of dynamic damping of oscillations. An important role in ensuring such developments is played by areas of research focused on the development of methods of mathematical modeling. Based on the research it is shown that the vibration field of the vibrating technological machine is formed under the influence of several factors, which are determined by the simultaneous action of several force perturbations, asymmetry of inertial and elastic properties of the mechanical system, the presence of additional connections. The introduction of additional links in the structure of the mechanical oscillating system of the vibrating machine, can significantly affect the structure of the vibration field, providing the choice of conditions for rational organization of the technological process of vibration processing, such as vibration hardening, crushing, transportation, screening.
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Stansby, Peter K., Jamie N. Pinchbeck et Tom Henderson. « Spoilers for the suppression of vortex-induced oscillations (Technical note) ». Applied Ocean Research 8, no 3 (juillet 1986) : 169–73. http://dx.doi.org/10.1016/s0141-1187(86)80017-7.
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Zhang, Weijia, Wei Zhang et Dongning Hao. « Adjustable Coupled Optoelectronic Oscillator Based on Double Frequency Output ». Journal of Nanoelectronics and Optoelectronics 15, no 6 (1 juin 2020) : 769–76. http://dx.doi.org/10.1166/jno.2020.2797.
Texte intégralRésumé :
At present, the research and development of high-speed communication technology and the more detailed division of communication frequency band have become the hot spots all over the world, which also puts forward a greater technical challenge to the down-conversion system in the receiver. However, the key to the signal receiving performance of down-conversion system is the local vibration performance. Low phase noise, tunable wideband and strong anti-electromagnetic interference have become the new directions for the future research on oscillator. Compared with the traditional microwave local oscillator, the technical advantage of the optoelectronic oscillator is more obvious, and more research and development space is left for the development of the new frequency band of communication technology in the future. The tunable coupling optoelectronic oscillator based on the double frequency output designed in this paper uses the equivalent light source of the ring path to replace the laser, and the wavelength interval of the output spectrum is changed by adjusting the length difference of the optical fiber cavity of the ring path filter. At the same time, by adjusting the bias voltage of the double-output intensity modulator, the oscillator suppresses the fundamental frequency signal and achieves the output of the two-frequency signal. After the test, it can be known that when the optical carrier wavelength of the oscillator is 1551 nm, the tuning range of the output fundamental frequency is 1.8–9 GHZ; The output range of double frequency is 3.6–18 GHz, the output power is greater than 10 dBm, and the phase noise changes slightly at different output frequencies, which is about –102 dBc/Hz.