Basic Array Research Articles

An Acoustic Array Sensor Signal Recognition Algorithm for Low-Altitude Targets Using Multiple Five-Element Acoustic Positioning Systems with VMD

To solve the problem in target acoustic signal processing and recognition when the target flies at a low altitude based on the acoustic positioning system, which is often affected by external interference and brings false information, this paper proposes a target signal processing and recognition algorithm for low-altitude target acoustic positioning based on variational modal decomposition and the test method of multiple five-element acoustic arrays. This algorithm uses VMD to decompose the target signal into modal components with different central frequencies and then performs wavelet threshold processing on the low-frequency part of the signal. After determining the remaining signal components and the low-frequency part’s threshold, the residual component is reconstructed. Based on the test principle and calculation model of the five-element acoustic positioning system, following processing of the low-altitude target acoustic positioning signal using variational modal decomposition, the cross-correlation function method is introduced to perform correlation operations on the basic array of five acoustic sensors and then obtain the time value and time difference of the target acoustic information in each acoustic sensor, ultimately determining the spatial position of the target. Finally, we used the data fusion processing method for target coordinates in multi-acoustic basic arrays to determine the actual target position. By comparing the results obtained using the high-speed camera method with those of the proposed approach, it was found that the average error in the test area of 100 × 100 m was less than 1 m.

Возможности цифровой трансформации малых и средних сельскохозяйственных предприятий в современных условиях

Abstract. The author presented the results of scientific developments of data transformation when performing certain tasks (inventory, sale of grain to the population) by a visiting employee using a mobile application. The purpose of the study is to develop theoretical provisions and practical recommendations to ensure the solution of economic problems of the functioning of small and medium-sized businesses of the agro-industrial complex using a mobile application. Methods. In the course of the study, general scientific methods of theoretical and empirical knowledge were used: analysis and synthesis, monographic, basic array, design-constructive, deduction and induction, economic-statistical and economic-mathematical methods (comparison, summary and grouping, tabular, graphic). Experimental method, practical modeling, including conducting a statement experiment, analysis and generalization of the obtained data. Results. The development of small and medium-sized agricultural enterprises as a socio-economic phenomenon affects many objects and generates certain connections between them, which allows us to consider small and medium-sized businesses from the point of view of systematic analysis. The conceptual interest and capabilities of agricultural producers in a system approach to human resources management with optimization of the main technological process management system will allow achieving an effective result of activities in the innovative environment of the organization. The results of research work can serve as a theoretical and practical basis for the activities of owners, leaders of small and medium-sized businesses in order to improve the process of digitalization of agricultural production; for the activities of state authorities – support for the development of small and medium-sized businesses with the aim of economic growth of the country; for investors – assessment of investment opportunities in the agro-industrial complex. Scientific novelty. A mechanism has been developed to optimize and improve the efficiency of production processes; attracting domestic and foreign investments in the development of industries of the agro-industrial complex. Feeding the country is a great mission, fulfilling it one of the main components of national security and preserving the integrity of the country. The undisputed priority will be interest in an effective, balanced production process, innovative and technical development and digitalization of agriculture.

Millimeter wave array-HIS antenna for imaging applications

The combination of a patch array antenna with a High Impedance Surface (HIS) metasurface at mmWave frequencies has been studied. The antenna is intended for a collision avoidance imaging application, which will help blind or visually impaired people in their daily lives. A compact and cost-effective uniplanar design, operating in the mmWave unlicensed frequency band (24.05–24.25 GHz), has been reached. Multiple arrangements and dispositions of the HIS unit-cells with the array have been explored in order to improve the radiation parameters of the basic design. Both, the basic array and the array-HIS combination, have been manufactured using laser micromachining. Prototypes have been measured in an anechoic chamber and measurement results have been confronted with the simulation ones in terms of bandwidth and radiation properties. A comparison with the state-of-the-art antennas at 24 GHz has been performed to endorse the achievements of this work.

Исследование экономической безопасности Центрального федерального округа Российской Федерации: динамический анализ и моделирование

Subject/topic. The article is devoted to the study of economic security indicators of the Central Federal District (CFD) of Russia. The object of this study is the Central Federal District of the Russian Federation. The subject of the study is the indicators of economic security of the region. Goals/tasks. Based on the list of indicators formed in accordance with the «Strategy of Economic Security of the Russian Federation until 2030» to determine the composition of the economic security of the regions of Russia, to classify them, to analyze the dynamics, on the basis of which to build economic and mathematical models of changes in the main parameters of economic security of the Central Federal District. Methodology. In the course of the study, modern methods of scientific and statistical group and mathematical modeling were used: indicative and basic array, scientific generalizations, grouping, dynamic series, correlation and regression analysis. Results. The article systematizes and studies the economic security of the Central Federal District of the Russian Federation, which made it possible to determine the problems of economic security of this territory, the prevailing trends and causes of negative dynamics of indicators, as well as to identify the most significant factors determining the change in the effective parameters of economic security using the constructed multifactor model. Conclusions/significance. The novelty consists in the theoretical justification of the economic security of the region, taking into account the systematization and grouping of economic security indicators at the regional level in accordance with the industrial and commercial, innovative and technical, and socio-personnel spheres of life. Application. The results of the study can be applied in practice in the formation or adjustment of the medium-term economic policy of the regions of the Russian Federation, as well as in general to monitor the dynamics of economic security at the regional level in the implementation of the goals and objectives of the current economic policy of the state.

Ka-Band Huygens Antenna Array With Very High Aperture Efficiency and Low Sidelobes

A Ka-band Huygens antenna array with extremely high aperture efficiency (AE) and low sidelobe levels is reported for 5G millimeter-wave (mm-wave) wireless applications. The basic array element is an innovative Huygens subarray consisting of two open rectangular waveguides that form an aperture consisting of a 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 2 set of orthogonal, tightly coupled electric and magnetic elements separated by a virtual gap that are balanced, in- phase, and radiate Huygens cardioid patterns. A larger 8 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times16$ </tex-math></inline-formula> element array is then realized with 64 of these 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 2 subarrays. With excitations of equal amplitude, the full broadside-radiating array achieves an AE up to 97.5% in the operating bandwidth, which is very close to the 100% limit associated with an ideal uniform aperture distribution. Moreover, a highly efficient and compact feed network with tapered-amplitude and in- phase excitations from the array center to its edges is designed to achieve sidelobe and backlobe levels less than −20 dB. The −10 dB impedance bandwidth covers 26.7–29.65 GHz, and the peak realized AE (RAE) reaches 82%. A full-aluminum array prototype was fabricated with standard machining processes and tested. The measured performance characteristics agree well with their simulated values, confirming the efficacy of their designs.

IDENTIFICATION OF THE IMPACT POSITION IN A REINFORCED CONCRETE STRUCTURE BASED ON THE ANALYSIS OF THE RESPONSE OF VIBRATION SENSORS

The article presents the results of an experiment to study the vibration response of a large-scale reinforced concrete model structure to an impulse load. The load was a series of impacts along the normal to the surface of the element and was applied to all the main structural ele-ments (columns, crossbars and floor slabs). The vibration response was recorded by a system of sensors-accelerometers distributed over the structural elements and synchronized with the accelerometer mounted on the striker. The results of measurements of acceleration vibrograms were saved as digital files. An array of vibrograms recorded by the entire complex of sensors in response to test impacts on the main structural elements made up a vibration portrait of the structure. As a result of processing this information, an array of data was obtained on the propa-gation time of the vibration signal from each signal source to each of the sensors of the registra-tion system (basic array of responses).Key words: Impact localization, accelerometer, The data obtained were used to solve the problem of determining the location of an arbi-trary impact on a structure. To do this, the vibration response recorded by the sensor system during an arbitrary impact was compared with the base array of responses. The comparison was made on the basis of the calculation of the pair correlation coefficients. The resulting spatial distribution of the correlation coefficients made it possible to identify the position of the shock load application. It corresponds to the structural element that has the maximum value of the correlation coefficient. The proposed algorithm was demonstrated on an example where one of the test shocks that participated in the FORMATION of the basic vibration portrait was used as an unknown load. In a numerical experiment using the proposed algorithm, it was found that the accuracy of the impact site identification corresponds to the characteristic step of the structural elements. It is shown that the accuracy correlates with the number of sensors of the registration system and their distribution throughout the structure. The developed algorithm for identifying the place of impact load application can be effec-tively used in the development of automated systems for deformation monitoring.

All-to-All Broadcast in WDM Linear Array with 3-length Extension

All-to-all broadcast communication, distributing messages from each node to every other node, is a dense communication pattern and finds numerous applications in advanced computing and communication networks from the control plane to datacenters. In this article, a linear array is extended by directly linking all nodes which are separated by two intermediate nodes with additional fibers and this network is referred as linear array with 3-length extension. The wavelength allotment methods are proposed to realize all-to-all broadcast over WDM optical linear array with 3-length extension under multiple unicast routing model and the wavelength number needed atmost to establish all-to-all broadcast is determined. The wavelength number needed atmost to establish all-to-all broadcast in a linear array with 3-length extension is reduced by a minimum of 61% and a maximum of 66% when compared to a basic linear array. Similarly, the wavelength number needed atmost to establish all-to-all broadcast is reduced by a minimum of 24% and a maximum of 33% when compared to linear array with 2-length extension.

Projectile Explosion Position Parameters Data Fusion Calculation and Measurement Method Based on Distributed Multi-Acoustic Sensor Arrays

In conventional weapon test field, the parameter of projectile explosion position is an important index to measure the control ability and damage efficiency of fuze. Due to the random deviation of gun firing and the difference of detection performance of fuze itself, the projectile explosion position is uncertain and relatively scattered in terminal ballistic, which is easy to miss the projectile explosion information. In order to obtain the parameters of projectile explosion position in large area of in terminal ballistic, this paper constructs a projectile explosion position testing system with distributed multiple acoustic sensor basic arrays, establishes the calculation model of projectile explosion position by a basic array, researches a multi-source data fusion algorithm based on the measurement data of multiple array acoustic basic arrays and gets real projectile explosion coordinates. To improve the measurement accuracy, we use the wavelet transform filtering method to filter the output signal of the acoustic sensors, and propose the time extraction algorithm of the projectile explosion acoustic signal with the wavelet modulus maximum. Through experiment and analysis, we collect the sound signal of the actual projectile explosion and verify the rationality and correctness of the proposed calculation model and algorithm.

The Array Optimization of Vertical Axis Wind Turbine Based on a New Asymmetric Wake Model

With the increasing demand for wind energy, the vertical axis wind turbine (VAWT) is attracting more and more attention. In order to design the VAWT array for better performance, the VAWT wake model needs to reflect the wake characteristics well. Based on the asymmetric wake characteristic, a new VAWT wake model is proposed in this paper, which is a combination of two semi Gaussian functions with different deviations, and can be called the “double semi Gaussian functions wake model”. The model is simple and has only four parameters (mean, amplitude, left deviation and right deviation). Compared with the traditional Gaussian and Top-hat model, this model can better reflect the asymmetric characteristic of the VAWT wake. In particular, it can describe the behavior of wake merging in the case of counter-rotating twin turbines. Based on this wake model, the velocity field of VAWT array can be reproduced accurately. The goal function is mainly based on the performance of a basic array unit, and it can ensure the rapidity of the optimization process. The optimal arrangements under two different criteria are analyzed. Moreover, the truncation ratio is introduced to ensure that the downstream turbine works at the rated condition, and the optimal arrangements under different truncation ratios are analyzed. In this paper, the proposed wake model provides a good choice for the preliminary design of the VAWT array, and some relevant suggestions on the array arrangement have been put forward.

Human Food Dynamics in Highly Seasonal Ecosystems: A Case Study of Plant-Eating in Riverine Communities in Central Amazon

Food habit studies in the Amazon emphasize the consumption of fish and manioc (Manihot esculenta) flour as basic diet in different ethnic groups, while little is known about human plant-related diet dynamics during the hydrological regime. In a scenario of food transition in rural Amazonia, with insertion of industrialized items in the diet, traditional food and consumption of regional products have undergone transformations, affecting the autonomy and lifestyle of traditional populations. Considering this, the objectives of the current case study were: (1) to contextualize plant-related eating habits in five Riverine communities on the Lower Purus River and (2) to characterize the dietary dynamics of plant eating according to the hydrological regime, considering the provenance of food items. We conducted interviews and sample collection in both low- and high-water seasons. We calculated species richness and diversity per meal and season and used multivariate analysis to access differences in plant consumption between seasons. The greatest richness and diversity of plants is consumed in the flooding season and mainly as snacks, the meal most susceptible to being replaced by industrialized foods. Despite a significant difference in diet between seasons, the basic array of plants consumed is similar in both seasons, with availability topped up by external purchases. This tendency deserves attention and action from public policies aimed at providing food security in the region.

Calculation Model of Projectile Explosion Position by Using Acousto-Optic Combination Mechanism

In order to accurately calculate the projectile explosion position, this paper takes the five acoustic sensors as a basic array, and proposes a test method for the projectile explosion position based on acousto-optic combination detection of triangular basic array and form acousto-optic combination test system. Combining with the spatial layout of triangular basic array, we derive the calculation model of projectile explosion position parameters of each basic array; use the wavelet transform analysis method to filter the acoustic sensor signal, and utilize the cross-correlation function to establish the time delay estimation processing model of the projectile explosion acoustic signal in the same basic array and obtain the time difference of each sensor in the basic array. According to the basic array acoustic sensor collected signal in experiments, we analyze the distribution characteristics of acoustic signal strength generated by different projectile explosion, and calculate the projectile explosion position. By comparing with the height parameter data collected and processed by high-speed camera, the results show that the measurement accuracy of the proposed method is better than 0.6m in the range of 150m $\times150\text{m}$ , which verify the efficiency of the measurement method of projectile explosion position by using acousto-optic combination test mechanism.

БАЗОВІ ПІДХОДИ ДО СИСТЕМНОГО ПРОЕКТУВАННЯ ВАЛКОВИХ ПРЕСІВ ЗА МОДУЛЬНИМ ПРИНЦИПОМ

The work aims to form basic approaches to the system design of roller presses on a modular basis. For the design of modern roller presses in many industries, the aggregate-modular principle of equipment creation is actively used. In this regard, the need to further develop methods for roller presses analysis and design is urgent. The issues of development of the scientific base for the synthesis of rational layout and design solutions of roller presses taking into account the requirements for the implementation of the technological process of pressing are becoming especially relevant. The paper shows that despite the large number of works devoted to the study of the briquetting process in roller presses, the process of creating a press design is iterative in nature of trial and error. This is due to the multifactorial process and briquetting technology. The main interrelated factors influencing the briquetting process are highlighted. The main components of the system design of roller presses and the system approach to modeling the rational design of these machines using the methods of structural-parametric synthesis and analysis are formulated. The result of structural and parametric synthesis of the rational design of the roller press is presented in the form of tables, graphs, and text files that contain a sufficient set of information for development in automated design systems package of design documentation for the production of the roller press. An approach to the design of roller presses on a modular basis is formulated. An example of generalized decomposition of a roller press design of an Iron &amp; Steel Institute from basic modules is given. The roller presses of the Iron &amp; Steel Institute design basic elements data array have been created, which can be used when creating new modifications of presses on a modular basis. Parameters, target functions, and algorithms for designing roller presses are formulated

A Planar Ultrawideband Wide-Angle Scanning Array Loaded With Polarization-Sensitive Frequency-Selective Surface Structure

This article presents a fully planar ultrawideband wide-angle scanning tightly coupled array. A tightly coupled element, which has a low input resistance, is used as the basic array element. The element can be fed by a simple microstrip-to-coaxial transition, obviating the need for an additional impedance transform structure. To improve the scan performance of the array in both the E- and H-planes, a polarization-sensitive frequency-selective surface (FSS) structure, whose effective dielectric constant for the TM mode incidence wave and TE mode incidence wave can be changed, respectively, by different structural parameters, is designed to serve as the wide-angle impedance matching (WAIM) layer. The FSS structure is printed on the superstrate dielectric directly without an additional dielectric layer, resulting in a low-cost array. The proposed array can work in 3.7:1 bandwidth with voltage standing wave ratio (VSWR) $11\times11$ prototype is fabricated and measured. The measured results of the fabricated array show good agreement with simulations, proving the feasibility of the design.

A Planar Wide-Angle Scanning Phased Array With $X$ -, $Ku$ -, and $K$ -Band RCS Reduction

This communication presents an artificial magnetic conductor (AMC) structure-loaded phased array with broadband low-RCS and wide-angle scanning performance. A substrate integrated with the cavity-backed antenna with wide beamwidth and decoupling cavity is used as the basic array element to increase the field-of-view scanning range of arrays. Meanwhile, a checkerboard-shaped AMC structure with a broadband region of 180° (±37°) phase difference is designed and loaded around the array to reduce its RCS in and out of the band. This communication is validated through measurements that matched well with simulations. The proposed array operates at 10.8 GHz and provides a wide scanning region from −70° to +70° in the H-plane with particularly small gain fluctuation (±1.5 dB). Moreover, the backscattering of the proposed array can be reduced to −6 dB for both TE and TM polarizations, covering the $X$ -, Ku -, and $K$ -bands. The proposed approach has the potential application in smart skin designs due to its low profile, powerful scanning ability, and broadband RCS reduction.

240. A Developmental Perspective on Brain Network Architecture, Nodal Abnormalities and Susceptibility or Resilience to Maltreatment

Childhood maltreatment is an important risk factor for psychopathology. However, some maltreated individuals appear remarkably resilient even though they have the same basic array of imaging abnormalities as maltreated individuals with psychopathology. We seek to identify compensatory brain alterations enabling resilient individuals to maintain mental well-being despite alterations in stress-susceptible structures.

A Mixed Circular/Linear Dual-Polarized Phased Array Concept for Automotive Radar—Planar Antenna Designs and System Evaluation at 78 GHz

A planar antenna array front end for automotive applications in the 78 GHz band is discussed and evaluated. Separate antenna arrays for transmit and receive are realized on RF substrate with the objective to provide a very cost-effective and compact design. The basic array column consists of 10 dual-polarized square patch elements and launches a fan beam that illuminates a wide sector in azimuth but a narrow sector in elevation. The orthogonal linear polarizations are combined via a microstrip quadrature power splitting network in order to excite a single circularly polarized wave on transmit. On receive, the array column is arranged multiple times next to each other to allow for digital beamforming in azimuthal direction. A prototype consisting of three receiving columns has been fabricated and measured. Grating lobes are reduced to an overall sidelobe level of less than −10 dB by a time-division multiplex scheme that switches through several transmit arrays in different locations. Radar system simulations based on the measured antenna patterns demonstrate a very good discrimination of elementary polarimetric scattering objects.

Different Multilayer Substrate Approaches to Improve Array Antenna Characteristics for Radar Applications

The aim of this paper is to investigate deeply in multi-layer substrate technique as a way of improving the characteristics of patch array antenna for electronic scanning radar application. The basic array antenna consists of 8 patches mounted on a FR-4 substrate and operating at 3GHz frequency. The feeding technique is microstrip technology. This structure has some disadvantages as a poor gain and a narrow bandwidth. In fact, the obtained gain value does not exceed 7 dB which could be explained by the lossy nature of the FR4 substrate. On the other side, the narrow bandwidth is caused by the microstrip limitations. For this reason, the technique of multi-layer substrate is proposed in this paper. Many approaches are investigated and the distance between the layers is studied. The design and simulations of each approach are performed under the tool Advanced Design System of Keysight Company. A comparison between simulation results of all approaches including simulation results of the basic array antenna will be analyzed.

Dual-Band Wide-Angle Scanning Phased Array Composed of SIW-Cavity Backed Elements

In this communication, an aperiodic dual-band phased array with wide-angle scanning performance is presented. A substrate integrated waveguide cavity-backed antenna, which has wide beamwidths at 4.8 and 5.8 GHz, is used as the basic array element. The phased array contains eight subarrays with an equally spaced arrangement, and each subarray is arranged in a symmetric structure. Theoretical and optimization methods, in which the main beams of the subarray and the full array are coincident and the maximum sidelobe of the full array points to the null of the subarray, are proposed for sidelobe reduction. Based on the optimized results, the main beam of the phased array can scan from −75° to +75° at both the frequency bands, and the array supports the 3 dB beam coverage from −86° to +86° at the low-frequency band and from −82° to +82° at the high band, respectively. The phased array is simulated, fabricated, and measured. The measured results validate its wide-angle scanning performance.

Arrays of Position-Sensitive Virtual Frisch-Grid CdZnTe Detectors: Results From a $4\times 4$ Array Prototype

Position-sensitive virtual Frisch-grid (VFG) CdZnTe (CZT) detectors offer a unique capability for correcting the response nonuniformities caused by crystal defects. This allowed us to achieve high energy resolution, while using typical-grade commercial CZT crystals with relaxed requirements to their quality, thus reducing the overall cost of detectors. Another advantage of the VFG detectors is that they can be integrated into arrays and used in small compact hand-held instruments or large-area gamma cameras that will enhance detection capability for many practical applications, including nonproliferation, medical imaging, and gamma-ray astronomy. Here, we present the results from testing small array prototypes coupled with front-end application-specified integrated circuit. Each detector in the array is furnished with 5-mm-wide charge-sensing pads placed near the anode. The pads signals are converted into XY coordinates, which combined with the cathode signals (for Z coordinates) provide 3-D position information of all interaction points. The basic array consists of a number of detectors grouped into $2\times 2$ subarrays, each having a common cathode made by connecting together the cathodes of the individual detectors. These features can significantly improve the performance of detectors while using typical-grade low-cost CZT crystals to reduce the overall cost of the proposed instrument.

Energy Efficient Wireless Performance Monitoring System For Solar Panel

For a PV array, system monitoring is considered important to analyze the stability and performance. The simple monitoring system involves a data logging system with wired cables for transmitting data. Removing all those drawbacks observed in the existing system this proposed work is designed for the wireless monitoring of photovoltaic cell as a high precision solar array monitoring system. It is planned to measure the basic PV array characteristics like Module Temperature (T), Open Circuit Voltage (Voc), Short Circuit Current (Isc) and wirelessly transmit the data into real time GUI in the computer. The GUI was developed using the PROCESSING software. The commercially available WPAN hardware module ZigBee is used for implementation with API protocol for exchanging information. A sensor node with XBee and a set of analog sensors (eliminating the use of controllers at the sensor node) for measuring current and voltage generated in the PV array has been deployed. A coordinator node with Atmel microcontroller and Xbee connected with a PC to analyze the parameters.