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It is proposed to apply the wavelet transform to localize in time the frequency components of the information signals in this article. The wavelet transform allows to fulfil time-frequency analysis of signals, which is very important for studying the structure of a composite material from the mode composition of free oscillations. The proposed appr...
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... we consider the wavelet transform of signals received in the intact and damaged area of a cellular panel with a thickness of 20 mm. The amplitude spectra of these signals are shown in Fig. 3, 4. The estimated amplitude spectra preliminarily determine the frequency range within which the wavelet transform will be performed -zone I in Fig. 3, 4. Fig. 5 shows plots of the amplitude wavelet spectra of these signals, calculated by a Morlet wavelet in the selected frequency range. From these figures it can be seen that, for ...
Context 2
... we consider the wavelet transform of signals received in the intact and damaged area of a cellular panel with a thickness of 20 mm. The amplitude spectra of these signals are shown in Fig. 3, 4. The estimated amplitude spectra preliminarily determine the frequency range within which the wavelet transform will be performed -zone I in Fig. 3, 4. Fig. 5 shows plots of the amplitude wavelet spectra of these signals, calculated by a Morlet wavelet in the selected frequency range. From these figures it can be seen that, for example, the 1 st , 2 nd and 3r d modes of oscillations change the nature of the attenuation with the appearance of a defect. In fig. 6 shows the restored ...
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Citations
... Streaming data is transmitted between the nodes of the superimposed network along the routes selected by the underlying protocols [19,20]. Controlling the data transmission process will avoid congested areas in the network, increase the throughput and improve the reliability of the network as a whole [2,3,24,43,60,62]. Overlay networks rely on tree and multi-link structures [12,16,71]. ...
Wireless Touch Networks (WTN) have become increasingly important with the emergence of the Internet of Things (IoT) and are regarded as a class of self-organizing networks. This article presents an overview of the construction principles, routing protocols, quality of service parameters, traffic models, and characteristics of WTN. The article also explores the application of dynamic routing protocols for constructing a self-organizing network of autonomous IoT systems. Known dynamic routing protocols for mobile radio networks are reviewed and the advantages and disadvantages of proactive and reactive approaches are discussed.
... coefficients in Hartley bases and cosine functions. Similar results are characteristic in the case of the use of discrete Fourier transforms, Haar and discrete sine transforms [15,16]. The spectral alignment is performed by a signal that is obtained by averaging 500 realizations for each of the sample zones studied. ...
... Systems of linear equations that need to be solved to construct splines are well conditioned, which allows to obtain the coefficients of polynomials with high accuracy. There are many types of interpolation splines [15]. The paper proposes and studies a method for constructing approximations of dependencies of scheduling coefficients on the degree of impact damage using Hermite cubic splines and quadratic splines [21,22]. ...
The article describes the approach to the formation of a simulation model of information signals, which are typical for objects with different types of defects. The dispersive analysis of the signal spectrum components in the bases of the discrete Hartley transform and the discrete cosine transform is carried out. The analysis of the form of the reconstructed information signal is carried out depending on the number of coefficients of the spectral alignment in Hartley bases and cosine functions. The basis of orthogonal functions of a discrete argument is obtained, which can be used for the spectral transformation of information signals of a flaw detector. A method of simulation of information signals has been developed and experimentally investigated, which allows taking into account the deterministic and random components of the characteristics of real information signals. References 24, figures 13, tables 3.
... A significant impact on the results of diagnostics of EM nodes is exerted by their operating conditions and operating modes. So, for aviation applications [28,29], the essential requirement is failure-free operation, that is, a low probability of accidental malfunctions; for power machines [30]-a significant resource, durability. ...
... Therefore, an essential point in diagnosing a particular EM unit is the choice of accelerometer locations. So, for example, in the case of diagnosis of rolling bearings, accelerometers are usually located on bearing shields, and if the state of pressing of a charged magnetic core is diagnosed-on the stator pressure plate [27][28][29][30][31]. ...
Examples of building models and measures in monitoring and diagnostics of electric power objects are given. It is known that accuracy and reliability of results of diagnostics of technical objects depends on many factors. And, not in the last place, from qualitatively formed training sets which on different parameters and characteristics correspond to certain technical conditions of investigated objects. The questions connected with the appearance of some physical processes and their mathematical models accompanying the work of electric power equipment units are considered. The results of mathematical models formation of training sets (measures) which correspond to different technical conditions and modes of robots of the investigated electric power equipment are given. The choice of diagnostic spaces, the coordinates of which are the estimates of parameters or functional characteristics of diagnostic signals, is justified. Known in statistics scattering ellipses are used as learning sets, the boundaries of which with a certain probability cover the data of the results of experiments obtained on real power equipment. A scheme and an algorithm implementing it are proposed, which allow to form learning sets that take into account both possible types of defects in individual nodes of electrical power equipment and their modes of operation (rotor speed of the electric machine, temperature of the diagnosed node, various degrees of electrodynamic and mechanical loading, etc.). This approach allows to use monitoring and diagnostics systems within the Smart Grid technology, which provides the possibility to diagnose power equipment in real time. For building training sets that correspond to both certain types of defects and modes of operation of power equipment units, the results of experimental studies obtained at the laboratory stands of the Institute of Electrodynamics of the National Academy of Sciences of Ukraine were used. As an example of practical application of the proposed models, the problem of constructing solving rules at vibrodiagnostics of rolling bearings of electric machines has been considered.
... Using a digital oscilloscope (FAS) allows to record and save information about the instantaneous values of currents and voltages in three phases of all lines suitable for the substation. Further processing of instantaneous values by the ANFAS device gives the desired set of mode parameters at the measurement point [1][2][3][4][5]. The high information content of this approach for obtaining EMP and the lack of the need for real-time operation make it possible to use new algorithms to determine the LoD that are inaccessible to microprocessor technology [6,7]. ...
... 4. In the absence of an earth SC (Y2 = 0), it can be determined the type of interphase SC and a special phase, if there is a two-phase SC (K (2) ). Checking for asymmetry can be performed with the condition: ...
Automation of damage location is based on the device and a set of algorithms. The device is built on the basis of a digital oscilloscope based on a computer (alarm recording). It allows to record and store information about the instantaneous values of currents and voltages in three phases of all lines suitable for the substation. Further processing of instantaneous values, performed by the device—analyzer of fixed alarms, gives the desired set of mode parameters at the measurement point. The chapter provides a block diagram of the device. The choice of the moment of the beginning and the duration of the emergency analysis interval is described. The section shows the difference between the developed device and analogs. The main advantage of the developed device is the ability to analyze the modes according to secondary informative parameters obtained after processing the instantaneous values of currents and voltages in the interval of analysis of the emergency mode. In this case, it becomes possible to use the criteria for determining the type of short circuit and the special phase. The block diagrams of algorithms of types of short circuits and a special phase are given. Also given the principles by which the location of a short circuit is determined.
... Improving the efficiency of the heat power equipment by increasing the technical level of automatic control systems is possible in two directions: (1) the use of modern technical means (computerized control complexes with high-precision, reliable, lowinertia sensors of technological parameters); (2) improvement of automatic control 1.13 The generalized block diagram of the automatic combustion process control system of a boiler unit (1-setpoint adjuster, 2-regulator, 3-sensor, 4-feedback unit, 5-executing mechanism, 6-regulator) system circuits (as a rule, due to the introduction of additional information signals into the control loop, indicating a change in process parameters, the use of more complex cascade control algorithms [24][25][26][27][28]). ...
The main factors affecting on the efficiency of the boiler are investigated. The influence of the excess air coefficient on the composition of the products of fuel combustion and heat loss with flue gases is analyzed. The necessity of forming a stoichiometric air-fuel mixture to ensure an energy-efficient mode of fuel combustion is shown. The analysis of modern types of burner devices with various types of fuel combustion schemes is carried out. A burner of the PBGM type was selected as a device for conducting experimental studies, which is suitable for use on low and medium power boiler units. The methods for monitoring the composition of the exhaust gases are analyzed. Modern systems for monitoring and controlling the process of fuel combustion in boiler units are considered. Among the main disadvantages of such systems: the availability of sampling and sample preparation systems; lack of frequency regulation of fans and smoke exhausters; long time system installation; a relatively significant payback period; appointments exclusively for large power boilers. The current state of the fleet of boiler units for communal and industrial heat power was studied. It is shown that the majority of small and medium-sized boilers do not meet the specified thermal characteristics, in particular, the efficiency of most boilers does not exceed 70%.
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... There are many systems for diagnosing heating equipment. Some of them are given in [11][12][13][14]. Further thermal imaging of pipelines will be considered. ...
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Products made of composite materials, unlike products made of metals, are formed from primary raw materials simultaneously with the formation of the materials themselves. In this case, the process of diagnosing of these materials is characterized by a large influence of random factors caused by changes in the properties of composites that arise as a result of the complexity of manufacturing processes, a large number of types of possible defects that do not lend themselves to a formalized description, the imperfection of diagnostic methods and defectoscopic equipment, and other factors. The reliability of the diagnostics in this case is determined not only by the physical methods used to obtain information about the technical condition of the product, but also by the mathematical models that are the basis of the diagnostic methods and the methods of processing the received information for the purpose of forming the spaces of diagnostic signs and making diagnostic decisions. In the tasks of diagnosing products made of composite materials, under the condition of a limited number of reference samples used for setting up diagnostic systems, the presence of an adequate model, according to which the synthesis of information signals characteristic of objects with various types of defects or degrees of damage occurs, is of great importance, because allows to solve several problems at the same time. First, the existence of such a model allows to create a set of information signals that correspond to possible defects of composites, and therefore can be used to train and adjust computerized diagnostic systems without physically manufacturing reference samples. Secondly, the developed model of the information signal can be used to select the limit value of the sensitivity of the computerized diagnostic system, evaluate its efficiency and adjust the main parameters, to determine the reliability of diagnosis and classification, etc.
Monitoring of power system objects is a particularly urgent task, the solution of which allows to ensure the stability of the power system and the provision of services. An effective means of implementing such monitoring is the use of unmanned aerial vehicles. The section describes the structural diagram of the on-board UAV power supply monitoring system, the functioning of which embodies the LPAB status monitoring method and the forecasting method. The proposed structure is completely autonomous, that is, it is placed on board the UAV and does not require the intervention of the ground operator in the flight process, which in turn minimizes the possibility of losing the UAV in case of lack of communication with the ground control point. An algorithm for estimating the remaining flight time of a UAV on electric traction has been developed, which illustrates the method of monitoring the UAV’s power supply and provides the possibility of optimal use of the UAV’s energy and safe landing of the UAV. The decision to continue or terminate the flight task of the UAV is made on the basis of the developed method using fuzzy logic. The operation of the method is based on information about the current voltage of the battery, its surface temperature, the temperature on board the UAV and the integral wind indicator.KeywordsLithium-polymer batteryTrouble-free flightDecision-making systemFuzzy logicCharge levelUnmanned aerial vehicle
Una de las técnicas más populares para analizar sistemas de procesamiento de señales digitales es la de Transformada de Fourier Discreta. El presente trabajo tuvo como objetivo el estudio de esta técnica, la cual se utilizó como una herramienta computacional para el desarrollo sobre una sinusoide, la identificación de un sistema Filtro de respuesta al impulso (FIR) y para el análisis espectral de una señal de audio. La metodología utilizada se basó en un estudio teórico-práctico aplicado a los conceptos de la mencionada técnica, ejecutando un algoritmo a través de un simulador numérico. Los resultados validan que los algoritmos desarrollados son aplicables en el análisis de señales digitales.
