bluuebunny/crossref_metadata_2025 huggingface dataset:
Imbalanced fault identification via embedding-augmented Gaussian prototype network with meta-learning perspective
Authors: Hou Rujie , Chen Zhenyi , Chen Jinglong , He Shuilong , Zhou Zitong
Published: November 2021

In practical engineering, the number of acquired fault samples from different categories can be vastly different due to the low probability of key equipment malfunctioning. When training the imbalanced data, many methods focus on balancing the number of samples or weights between different categories, which may be time-consuming and easy to over-fit. To address this problem, we propose the embedding-augmented Gaussian prototype network (EGPN), which applies a new training mechanism from the perspective of meta-learning. We only train the categories with large samples and the remaining categories only appear in the testing process to calculate untrained prototypes. EGPN includes a feature-embedding augmented module, weighted prototype module and metric module. Firstly, ordinary convolution and dilated convolution are mixed to capture different frequency bands simultaneously, and the residual attention module is added to highlight key features and suppress unimportant features. Different prototypes are calculated by weighting to the embedding vectors through the Gaussian covariance matrix. Finally, the classification is done according to the modified distance. The experiments in the two datasets indicate that the proposed method can effectively recognize the untrained categories with only a few samples used as the prototypes, and can tackle the problem of identifying imbalanced fault data efficiently.
Anisotropic strength behavior of single-crystal TATB
Authors: Kroonblawd Matthew P , Steele Brad A , Nelms Matthew D , Fried Laurence E , Austin Ryan A
Published: November 2021

High-rate strength behavior plays an important role in the shock initiation of high explosives, with plastic deformation serving to localize heat into hot spots and as a mechanochemical means to enhance reactivity. Recent simulations predict that detonation-like shocks produce highly reactive nanoscale shear bands in the layered crystalline explosive TATB (1,3,5-triamino-2,4,6-trinitrobenzene), but the thresholds leading to this response are poorly understood. We utilize molecular dynamics to simulate the high-rate compressive stress–strain response of TATB, with a focus on understanding flow behavior. The dependence of strength on pressure and loading axis (crystal orientation) is explored. The deformation mechanisms fall broadly into two categories, with compression along crystal layers activating a buckling/twinning mode and compression normal to the layers producing nanoscale shear bands. Despite the complexity of the underlying mechanisms, the crystal exhibits relatively straightforward stress–strain curves. Most of the crystal orientations studied show rapid strain softening following the onset of yielding, which settles to a steady flow state. Trajectories are analyzed using five metrics for local states and structural order, but most of these metrics yield similar distributions for these deformation mechanisms. On the other hand, a recently proposed measure of intramolecular strain energy is found to most cleanly distinguish between these mechanisms, while also providing a plausible connection with mechanochemically accelerated decomposition kinetics. Localization of intramolecular strain energy is found to depend strongly on crystal orientation and pressure.
Synthesis of vertically-aligned large-area MoS2 nanofilm and its application in MoS2/Si heterostructure photodetector
Authors: Lei Yong , Yang Xiaozhan , Feng Wenlin
Published: November 2021

Van der Waals heterostructures based on the combination of 2D transition metal dichalcogenides and conventional semiconductors offer new opportunities for the next generation of optoelectronics. In this work, the sulfurization of Mo film is used to synthesize vertically-aligned MoS2 nanofilm (V-MoS2) with wafer-size and layer controllability. The V-MoS2/n-Si heterojunction was fabricated by using a 20 nm thickness V-MoS2, and the self-powered broadband photodetectors covering from deep ultraviolet to near infrared is achieved. The device shows superior responsivity (5.06 mA W−1), good photodetectivity (5.36 × 1011 Jones) and high on/off ratio I
on/I
off (8.31 × 103 at 254 nm). Furthermore, the V-MoS2/n-Si heterojunction device presents a fast response speed with the rise time and fall time being 54.53 ms and 97.83 ms, respectively. The high photoelectric performances could be attributed to the high-quality heterojunction between the V-MoS2 and n-Si. These findings suggest that the V-MoS2/n-Si heterojunction has great potential applications in the deep ultraviolet-near infrared detection field, and might be used as a part of the construction of integrated optoelectronic systems.
Tips of tongues in the double standard family*
Authors: Banerjee Kuntal , Buff Xavier , Canela Jordi , Epstein Adam
Published: November 2021

We answer a question raised by Misiurewicz and Rodrigues concerning the family of degree two circle maps

F

λ

:
R
/
Z
→
R
/
Z

defined by

F

λ

(

x

)

≔
2
x
+
a
+

b

π

sin

(

2
π
x

)

with

λ
≔

(

a
,
b

)

∈
R
/
Z
×

(

0
,
1

)

.

We prove that if

F

λ

◦
n

−
i
d

has a zero of multiplicity three in

R
/
Z

, then there is a system of local coordinates

(

α
,
β

)

:
W
→

R

2

defined in a neighborhood W of λ, such that α(λ) = β(λ) = 0 and

F

μ

◦
n

−
i
d

has a multiple zero with μ ∈ W if and only if β
3(μ) = α
2(μ). This shows that the tips of tongues are regular cusps.
Novel derivation of equations of motion for a body falling with resistance
Authors: Chong Zhiwei , Wu Zhuoyi , Wei Yajun
Published: November 2021

The motion equations of a body under gravity and resistance linearly dependent on speed are usually analysed by solving differential equations. In this paper we report a derivation not explicitly involving differential equations but instead based on some elementary mathematical operations. The derivation uses only knowledge covered in a typical secondary school mathematics syllabus.
Enhancing the conversion efficiency of extreme ultraviolet light sources using a 2 µm wavelength laser
Authors: Yuan Y , Ma Y Y , Wang W P , Chen S J , Cui Y , Zi M , Yang X H , Zhang G B , Leng Y X
Published: November 2021

In this study, we use the FLASH radiation hydrodynamic code and the FLYCHK atomic code to investigate the energy conversion and spectra associated with laser–Sn target interactions with 1 and 2 µm wavelength lasers. We found that the conversion efficiency (CE) reached as much as 3.38% with the 2 µm laser, which is 1.48 percentage points higher than the 1 µm laser (CE = 1.9%). In addition, we analyzed the contribution of dominant ionization states to the emission spectrum for both lasers. We observed that the growths of the out-of-band emission eventually led to a broadening of the spectrum, resulting in a reduction of spectral purity for the 1 µm laser. By contrast, the emission main peaks were all centered near 13.5 nm for the 2 µm laser, which is beneficial for efficient emission of light with a 13.5 nm wavelength (relevant for nanolithographic applications).
Effect of a non-uniform magnetic field on two ion species plasma-wall transition
Authors: Deuja Atit , Basnet Suresh , Khanal Raju
Published: November 2021

Fluid theory has been employed to investigate the magnetized plasma-wall transition properties for two ion species plasmas with a uniform background of neutral gas density in the presence of an external magnetic field. The external applied magnetic field is parallel to the surface and its magnitude varies in the direction perpendicular to the surface. The governing equations of ion and electron fluids include ionization and collision with neutral atoms. A comparative study of transition parameters for non-uniform and uniform magnetic fields is performed at equal values of the magnetic flux density at x = 0. This study shows that the sheath region shrinks for the non-uniform magnetic field case, essentially in reason of the lower value of the average magnetic field intensity in the plasma-wall transition region. We introduce a figure of merit to quantify the nonuniformity of the magnetic field

(

B

m
a
x

−

B

m
i
n

)

/

B

m
a
x

, and show that for its value 0.21 it is possible to model the plasma-wall transition region considering the magnetic field as uniform and equal to its average value. Furthermore, we find that the density distribution of electrons close to the surface deviates from the Boltzmann distribution due to the influence of a strong magnetic field.
Fabrication and electroluminescence properties of alloyed CdS
x
Se1−x
quantum dots-based LEDs
Authors: Nguyen Huu Tuan , Chen Shutang , Duong Anh Tuan , Lee Soonil
Published: November 2021

We report on the facile synthesis of alloyed CdS
x
Se1−x
quantum dots (QDs) via a one-pot method using the simultaneous injection of Se and S source into a solution of the Cd precursor dissolved in a coordinating mixture of hexadecylamine and trioctylphosphine, during which the formation of CdS
x
Se1−x
nanocrystals was controlled by growth time at a temperature of 260 °C. In particular, the emission peak and full width at half maximum of the photoluminescence (PL) of alloyed CdS
x
Se1−x
QDs were tunable in the range of 588–604 nm and 36–38 nm, respectively, with a PL quantum yield of up to 55% by a reaction time of 60 min. Importantly, the structural advantage of alloyed CdS
x
Se1−x
QDs-based light emitting devices have been fabricated and their electroluminescence properties characterized. A good performance device with a maximum luminance and luminous efficiency of 761 cd m−2 and 0.82 cd A−1, respectively, was obtained.
Experimental study on mechanical properties of large NiTi superelastic shape memory alloy bars
Authors: Ning Qiujun , Zhu Lihua , Han Wei , Zhao Cheng
Published: November 2021

This study intensively examined the mechanical properties of large-sized superelastic shape memory alloy (SMA) bars, mainly focusing on their self-centering and energy dissipation capabilities. A detailed investigation on the effects of the heat treatment strategy, loading rate, strain amplitude, cyclic loading, prestress, and diameter of the SMA bars on their mechanical performance—residual strain, energy dissipation, equivalent viscous damping ratios, strength, and stiffness—was conducted. Furthermore, the fracture microstructure of monotonic tensile specimens was analyzed via scanning electron microscopy. The results indicated that the optimally heat-treated SMA bars show good superelasticity. The mechanical properties were relatively stable under constant strain loading–unloading training, which should be considered in engineering applications. The test results provided basic experimental data support for the engineering application of large SMA bars.
Broadband vibration energy harvester based on nonlinear magnetic force and rotary pendulums
Authors: Yan Qiang , Dai Xianzhi , Zhang Zhang , Wang Lijun , Wang Yong
Published: November 2021

A broadband vibration energy harvester based on nonlinear magnetic force and rotary pendulums is proposed in this paper. The harvester is mainly composed of a magnetoelectric transducer and a rotary pendulum fixed with four permanent magnets. In order to improve the working bandwidth of the harvester, two pairs of permanent magnets are added in the middle of the rotary pendulum by using magnetic nonlinearity. The mechanical–magnetic–electrical analytical model of the harvester is established, and the theoretical value obtained by the model is basically consistent with the experimental value. The results show that the harvester has a strong nonlinearity through the magnetic force. When the acceleration is 0.4 g, some typical testing results are as follows: the resonant frequency is 19 Hz, maximum peak–peak voltage is 94.1 V, half power bandwidth is 15.8 Hz, center frequency is 26.9 Hz, and the ratio of half power bandwidth to the center frequency is 58.73

%

.
Temperature oscillation in one-dimensional superlattice induced by phonon localization
Authors: Lu Longkai , Ma Dengke , Zhong Ming , Zhang Lifa
Published: November 2021

Thermal transport properties and thermodynamic quantities often present anomalous behaviors in low-dimensional systems. In this paper, it is found that temperature oscillates spatially in one-dimensional harmonic and weakly anharmonic superlattice. With the increase of anharmonicity, the temperature oscillation gradually disappears and a normal temperature gradient forms. Further analysis reveals that the formation of temperature oscillation is due to the localization of high frequency phonons which cannot be thermalized. Moreover, the localized modes interact weakly with heat reservoirs, thus, their contributions to local temperature remain negligible while varying the temperatures of heat reservoirs. The oscillated temperature profile is in a good agreement with Visscher’s formula. The temperature oscillation discovered here has great potential in applications of phononic devices for heat manipulation.
Molecule–molecule and atom–molecule collisions with ultracold RbCs molecules
Authors: Gregory Philip D , Blackmore Jacob A , Matthew D Frye , Fernley Luke M , Bromley Sarah L , Hutson Jeremy M , Cornish Simon L
Published: November 2021

Understanding ultracold collisions involving molecules is of fundamental importance for current experiments, where inelastic collisions typically limit the lifetime of molecular ensembles in optical traps. Here we present a broad study of optically trapped ultracold RbCs molecules in collisions with one another, in reactive collisions with Rb atoms, and in nonreactive collisions with Cs atoms. For experiments with RbCs alone, we show that by modulating the intensity of the optical trap, such that the molecules spend 75% of each modulation cycle in the dark, we partially suppress collisional loss of the molecules. This is evidence for optical excitation of molecule pairs mediated via sticky collisions. We find that the suppression is less effective for molecules not prepared in the spin-stretched hyperfine ground state. This may be due either to longer lifetimes for complexes in the dark or to laser-free decay pathways. For atom–molecule mixtures, RbCs + Rb and RbCs + Cs, we demonstrate that the rate of collisional loss of molecules scales linearly with the density of atoms. This indicates that, in both cases, the loss of molecules is rate-limited by two-body atom–molecule processes. For both mixtures, we measure loss rates that are below the thermally averaged universal limit.
Improving the steady-state coherence and entanglement of two coupled qubits via composite system-reservoir interactions
Authors: Li Xiao-Ming , Man Zhong-Xiao , Xia Yun-Jie
Published: November 2021

In this work, we study the improvement of steady-state coherence (SSC) and steady-state entanglement (SSE) of two coupled qubits by means of composite system-reservoir interaction constructed by a linear combination of orthogonal and parallel ones. We show that in the non-equilibrium case, the SSC and SSE can be significantly enhanced by increasing the parallel components of the interaction Hamiltonian between the system of interest and the heat reservoirs. In addition, we find that in the non-equilibrium case, increasing the parallel components can enlarge the temperature (temperature difference) region where the SSC can maintain nonzero values. In the equilibrium situation, however, the SSC and SSE are not affected by the parallel components of the composite system-reservoir interactions.
Evolutionary heuristic with Gudermannian neural networks for the nonlinear singular models of third kind
Authors: Sabir Zulqurnain , Wahab Hafiz Abdul
Published: November 2021

The presented research work articulates a new design of heuristic computing platform with artificial intelligence algorithm by exploitation of modeling with feed-forward Gudermannian neural networks (FFGNN) trained with global search viability of genetic algorithms (GA) hybrid with speedy local convergence ability of sequential quadratic programing (SQP) approach, i.e., FFGNN-GASQP for solving the singular nonlinear third order Emden-Fowler (SNEF) models. The proposed FFGNN-GASQP intelligent computing solver Gudermannian kernel unified in the hidden layer structure of FFGNN systems of differential operators based on the SNEF that are arbitrary connected to represent the error-based merit function. The optimization objective function is performed with hybrid heuristics of GASQP. Three problems of the third order SNEF are used to evaluate the correctness, robustness and effectiveness of the designed FFGNN-GASQP scheme. Statistical assessments of the performance of FFGNN-GASQP are used to validate the consistent accuracy, convergence and stability.
Feynman kernel analytical solutions for the deformed hyperbolic barrier potential with application to some diatomic molecules
Authors: M’hamed Ezzine M , Hachama M , Diaf A
Published: November 2021

In this paper, we derive the ℓ-states energy spectrum of the q-deformed hyperbolic Barrier Potential. Within the Feynman path integral formalism, we propose an appropriate approximation of the centrifugal term. Then, using Euler angles and the isomorphism between Λ3 and SU(1, 1), we convert the radial path integral into a maniable one. The obtained eigenvalues are in very good agreement with the numerical results. In addition, we applied our results to some diatomic molecules and obtained accurate results compared to the experimental (RKR) values.
Pseudospectral method for solving fractional Sturm-Liouville problem using Chebyshev cardinal functions
Authors: Afarideh Alireza , Dastmalchi Saei Farhad , Lakestani Mehrdad , Nemati Saray Behzad
Published: November 2021

This work deals with the pseudospectral method to solve the Sturm-Liouville eigenvalue problems with Caputo fractional derivative using Chebyshev cardinal functions. The method is based on reducing the problem to a weakly singular Volterra integrodifferential equation. Then, using the matrices obtained from the representation of the fractional integration operator and derivative operator based on Chebyshev cardinal functions, the equation becomes an algebraic system. To get the eigenvalues, we find the roots of the characteristics polynomial of the coefficients matrix. We have proved the convergence of the proposed method. To illustrate the ability and accuracy of the method, some numerical examples are presented.
Dynamics of quantum correlations in a qubit-qutrit spin system under random telegraph noise
Authors: Benabdallah Fadwa , Zad Hamid Arian , Daoud Mohammed , Ananikian Nerses
Published: November 2021

We study the dimensionless time evolution of the logarithmic negativity and geometric quantum discord of a qubit-qutrit XXX spin model under the both Markovian and non-Markovian noise channels. We find that at a special temperature interval the quantum entanglement based on the logarithmic negativity reveals entanglement sudden deaths together with revivals. The revival phenomenon is due to the non-Markovianity resulting from the feedback effect of the environment. At high temperatures, the scenario of death and revival disappears. The geometric quantum discord evolves alternatively versus time elapsing with damped amplitudes until the system reaches steady state. It is demonstrated that the dynamics of entanglement negativity undergoes substantial changes by varying temperature, and it is much more fragile against the temperature rather than the geometric quantum discord. The real complex heterodinuclear [Ni(dpt)(H2O)Cu(pba)] · 2H2O [with pba = 1,3-propylenebis(oxamato) and dpt = bis-(3-aminopropyl)amine] is an experimental representative of our considered bipartite qubit-qutrit system that may show remarkable entanglement deaths and revivals at relatively high temperatures and high magnetic field that is comparable with the strength of the exchange interaction J between Cu+2 and Ni+2 ions, i.e., k

B

T ≈ J and μ

B

B ≈ J.
Solitons propagation dynamics in a saturable PT-symmetric fractional medium
Authors: Haji Taghi Tehrani D , Solaimani M , Ghalandari Mahboubeh , Babayar-Razlighi B
Published: November 2021

In the current research, the propagation of solitons in a saturable PT-symmetric fractional system is studied by solving nonlinear fractional Schrödinger equation. Three numerical methods are employed for this purpose, namely Monte Carlo based Euler–Lagrange variational schema, split-step method, and extrapolation approach. The results show good agreement and accuracy. The effect of different parameters such as potential depth, Levy indices, and saturation parameter, on the physical properties of the systems such as maximum intensity and soliton width oscillations are considered.
Design and physics basis for the upcoming DIII-D SAS-VW campaign to quantify tungsten leakage and transport in a new slot divertor geometry
Authors: Abrams T , Sinclair G , Nichols J H , Unterberg E A , Donovan D C , Duran J , Elder J D , Glass F , Grierson B A , Guo H Y , Hall T , Ma X , Maurizio R , McLean A G , Murphy C , Nguyen R , Rudakov D L , Stangeby P C , Thomas D M , Zamperini S A
Published: November 2021

A set of experiments are planned to exploit the high SOL collisionality enabled by a tightly baffled slot divertor geometry to suppress tungsten leakage in DIII-D. A toroidal row of graphite tiles from the Small Angle Slot (SAS) divertor is being coated with 10–15 μm of tungsten. New spectroscopic viewing chords with in-vacuo optics will measure the W gross erosion source from the divertor surface with high spatial and temporal resolution. In parallel, the bottom of the SAS divertor is changed from a flat to a ‘V’ shape. New SOLPS-ITER/DIVIMP simulations conducted with drifts using the planned ‘V’ shape predict a substantial reduction in W sourcing and SOL accumulation in either B × ∇B direction relative to either the old SAS divertor shape or the open, lower divertor. Dedicated studies are planned to carefully characterize the level of W sourcing, leakage, and scrape-off-layer (SOL) accumulation in DIII-D over a wide range of plasma scenarios. Various actuators will be assessed for their efficacy in further reducing high-Z impurity sources and leakage from the slot divertor geometry. This coupled code-experiment validation effort will be used to stress-test physics models and build confidence in extrapolations to advanced, high-Z divertor geometries for next-step devices.
The EMU view of the Large Magellanic Cloud: troubles for sub-TeV WIMPs
Authors: Regis Marco , Reynoso-Cordova Javier , Filipović Miroslav D. , Brüggen Marcus , Carretti Ettore , Collier Jordan , Hopkins Andrew M. , Lenc Emil , Maio Umberto , Marvil Joshua R. , Norris Ray P. , Vernstrom Tessa
Published: November 2021

We present a radio search for WIMP dark matter in the Large Magellanic Cloud (LMC).
We make use of a recent deep image of the LMC obtained from observations of the Australian Square Kilometre Array Pathfinder (ASKAP), and processed as part of the Evolutionary Map of the Universe (EMU) survey.
LMC is an extremely promising target for WIMP searches at radio frequencies because of the large J-factor and the presence of a substantial magnetic field.
We detect no evidence for emission arising from WIMP annihilations and derive stringent bounds on the annihilation rate as a function of the WIMP mass, for different annihilation channels. This work excludes the thermal cross section for masses below 480 GeV and annihilation into quarks.
Discontinuous and continuous transitions of collective behaviors in living systems*
Authors: Li Xu , Xue Tingting , Sun Yu , Fan Jingfang , Li Hui , Liu Maoxin , Han Zhangang , Di Zengru , Chen Xiaosong
Published: November 2021

Living systems are full of astonishing diversity and complexity of life. Despite differences in the length scales and cognitive abilities of these systems, collective motion of large groups of individuals can emerge. It is of great importance to seek for the fundamental principles of collective motion, such as phase transitions and their natures. Via an eigen microstate approach, we have found a discontinuous transition of density and a continuous transition of velocity in the Vicsek models of collective motion, which are identified by the finite-size scaling form of order-parameter. At strong noise, living systems behave like gas. With the decrease of noise, the interactions between the particles of a living system become stronger and make them come closer. The living system experiences then a discontinuous gas–liquid like transition of density. The even stronger interactions at smaller noise make the velocity directions of the particles become ordered and there is a continuous phase transition of collective motion in addition.
Closed-loop control of a prosthetic finger via evoked proprioceptive information
Authors: Vargas Luis , Huang He (Helen) , Zhu Yong , Hu Xiaogang
Published: November 2021

Objective. Proprioceptive information plays an important role for recognizing and coordinating our limb’s static and dynamic states relative to our body or the environment. In this study, we determined how artificially evoked proprioceptive feedback affected the continuous control of a prosthetic finger. Approach. We elicited proprioceptive information regarding the joint static position and dynamic movement of a prosthetic finger via a vibrotactor array placed around the subject’s upper arm. Myoelectric signals of the finger flexor and extensor muscles were used to control the prosthesis, with or without the evoked proprioceptive feedback. Two control modes were evaluated: the myoelectric signal amplitudes were continuously mapped to either the position or the velocity of the prosthetic joint. Main results. Our results showed that the evoked proprioceptive information improved the control accuracy of the joint angle, with comparable performance in the position- and velocity-control conditions. However, greater angle variability was prominent during position-control than velocity-control. Without the proprioceptive feedback, the position-control tended to show a smaller angle error than the velocity-control condition. Significance. Our findings suggest that closed-loop control of a prosthetic device can potentially be achieved using non-invasive evoked proprioceptive feedback delivered to intact participants. Moreover, the evoked sensory information was integrated during myoelectric control effectively for both control strategies. The outcomes can facilitate our understanding of the sensorimotor integration process during human-machine interactions, which can potentially promote fine control of prosthetic hands.
Alfvén eigenmode classification based on ECE diagnostics at DIII-D using deep recurrent neural networks
Authors: Jalalvand Azarakhsh , Kaptanoglu Alan A. , Garcia Alvin V. , Nelson Andrew O. , Abbate Joseph , Austin Max E. , Verdoolaege Geert , Brunton Steven L. , Heidbrink William W. , Kolemen Egemen
Published: November 2021

Modern tokamaks have achieved significant fusion production, but further progress towards steady-state operation has been stymied by a host of kinetic and MHD instabilities. Control and identification of these instabilities is often complicated, warranting the application of data-driven methods to complement and improve physical understanding. In particular, Alfvén eigenmodes are a class of ubiquitous mixed kinetic and MHD instabilities that are important to identify and control because they can lead to loss of confinement and potential damage to the walls of a plasma device. In the present work, we use reservoir computing networks to classify Alfvén eigenmodes in a large labeled database of DIII-D discharges, covering a broad range of operational parameter space. Despite the large parameter space, we show excellent classification and prediction performance, with an average hit rate of 91% and false alarm ratio of 7%, indicating promise for future implementation with additional diagnostic data and consolidation into a real-time control strategy.
Evaluating the Effectiveness of an Intrusion Detection System Based on Matrix Games and Fuzzy Sets
Authors: Vilkov V B , Dergachev A I , Chernykh A K , Abu-Khasan M S
Published: November 2021

We consider a problem formulated as a matrix game in which the gain of officials using a specific intrusion detection system (criminal actions) of intruders (player 1) is the probability of timely detection of these criminal actions (player 2). As a rule, it is not possible to unambiguously set the probability of timely detection of criminal actions, so it is proposed to use the apparatus of fuzzy set theory to evaluate it. Reviewed and discussed the basic concepts of fuzzy set theory, and an example of practical application of this theory to assess the efficiency of the detection system of criminal damage. Application of fuzzy set theory in assessing the possible actions of an attacker can detect existing vulnerabilities in information security of automated systems continue to spend improving the detection of criminal acts (hackers) to prevent the possibility of applying economic and other damage to the company.
Efficiency of Installation of an Additional Gas-Air Heat Exchanger When Operating a Steam Boiler on Gas and Liquid Fuel
Authors: Bakirov F , Ibragimov E
Published: November 2021

The article presents the results of calculating the efficiency of reconstruction of the gas and air paths of a steam boiler when working on gas and liquid fuel due to the installation of additional gas-air heat exchangers. Due to the utilization of the thermal energy of the flue gases in the newly installed heat exchangers, the air is heated in front of the boiler air heaters and the fuel efficiency is increased by increasing the boiler efficiency. The increase in the efficiency of the "gross" boiler during the operation of the considered TGM-84 boiler on fuel oil with an average annual operating mode was 2.81 %. The flue gas temperature after the boiler air heaters was 178 °C, and the air temperature at the inlet to the air heaters was 99 °C at the average annual load of the boiler, which ensures an almost corrosion-free operation of the air heater packing. It is revealed that when the liquid fuel boilers, installation of new heat exchangers and their strapping on the side of the air and flue gas has a shorter payback period than the boiler gas fired. The simple payback period of the considered technical solution was 6,82 years when working on gas fuel and 1,35 years when working on liquid fuel.
Adaptive Threshold Scheme for Pulse Detection under Condition of Background Nonstationary Noise
Authors: Shcherbina A O , Lukovenkova O O , Solodchuk A A
Published: November 2021

The paper describes a new adaptive threshold scheme for detecting pulses in high-frequency signals against a background of non-stationary noise. The result of the scheme operation is to determine the pulse boundaries by comparing the signal amplitude-time parameters with the threshold. The threshold value is calculated in non-overlapping windows of fixed length and depends only on the background noise level. The detected pulses undergo additional shape checking, taking into account their characteristics. The parameters of the algorithms for detecting pulses and checking their shape can be adjusted for any type of high-frequency pulse signals. This threshold scheme is tuned to detect pulses in high frequency geoacoustic emission signals. The results of the scheme operation on an artificial signal and on fragments of a geoacoustic signal are given, a comparison is made between the proposed scheme and the previously used (outdated) one. The new threshold scheme proposed by the authors is less sensitive to the choice of the initial threshold value and it is more stable in operation. When processing 15-minute fragments of a geoacoustic signal, the new scheme correctly detects, on average, 5 times more pulses.
Development and Application of Convolutional Neural Network for the Recognition of Objects in the Scheme of Electric Grid
Authors: Rezaeva M A , Semendyaev R Y
Published: November 2021

One of the current design problems in the electric power industry is the labor intensity of synthesizing mathematical models to calculate the electrical modes of the network. It takes a lot of time to compose a detailed model of a large power system based on circuit diagram data. To simplify, speed up, and automate the data input, a convolutional neural network is proposed. In this paper the definition of convolutional neural network is given, its elements are described, the architecture of neural network is developed, the accuracy of its work on the schematic diagrams of various power systems is 0.84.
Graphical Analysis of Day - Night Temperature Difference by Interpolation and Approximation Methods for the Energy Converter of the Environment
Authors: Chelukhin V , Aung Piei Zon
Published: November 2021

Today, a lot of attention is paid to the search for environmentally friendly renewable energy sources. The most frequently considered such energy sources are wind energy, solar technology, the use of the energy of sea waves and biomass.

Each of them has a drawback that prevents its widespread adoption. For example, wind farms create noise during their operation, are rigidly tied to the place where there are acceptable wind resources.

To date, an energy converter has been developed, which works on the basis of the use of the ambient temperature difference during the day - the temperature is high during the day, and the temperature decreases at nightAs a rule, this temperature difference is in the range of about 5-9 degrees, although there are regions in which this difference is much higher, for example, in winter in Urengoy it can reach up to 30 degrees. An energy converter of this type is considered in works / 1-2/.

The basis of the operation of such a converter is the change in the linear size of bodies, for example, plexiglass, with a change in temperature. When the temperature rises during the day, when the temperature is high, the rod lengthens, while at night, when the temperature is low, the linear dimensions of the rod decrease. This is exactly what is used to obtain energy through the use of a container. A conventional capacitor is used, one plate of which is fixed, the second plate of this capacitor is movable and connected to a dielectric plexiglass rod. When the temperature changes, for example, at a high temperature, the rod lengthens, the plates of the container come closer and the capacity will be maximum. At night, when the temperature decreases, the plexiglass rod is shortened, the plate moves away and the capacity decreases.

If, at maximum capacity, the capacitor is charged and disconnected from the source, then the charge on it will be constant. At night, when the rod shrinks its linear dimensions, the movable plate moves away, the capacity falls. Since the charge on the container is constant, the voltage increases and we get an increase in energy, which is obtained from the day-night temperature difference and the change in the linear dimensions of the dielectric rod.
Computational Model for Radial Plain Bearing with Non-Circular Bearing Surface Profile and Fusible Coating on Shaft Surface
Authors: Mukutadze M A , Novakovich M V , Zadorozhnaya N S
Published: November 2021

The paper presents a study based upon: a Newtonian fluid flow equation (“thin layer”), a continuity equation, and an equation of the molten-profile radius for a shaft coated with a fusible metal alloy; considering a mechanical energy dissipation rate formula, the authors produced an asymptotic and accurate automodel solution for the zero approximation (melting ignored) and first approximation (adjusted for melting) of a radial plain bearing featuring a fusible metal coating and a bearing profile adapted to the specific friction parameters. The paper further presents analytical dependencies describing the molten surface radius, velocity and pressure fields for zero and first approximation. Besides, it determines the key operating parameters of the frictional couple, the bearing capacity, and the friction. It also shows how the parameters arising from the melting of the surface affect the bearing capacity and friction where the bearing surface profile is adapted to the specific conditions of friction.
Analysis and Development Potential of Predictive Models for Energy Flows of Autonomous Hybrid Energy Systems
Authors: Berdonosov V D , Vasilev G V , Zhivotova A A
Published: November 2021

The article is devoted to the analysis and development potential for predictive models of energy flows of autonomous hybrid energy systems. The article considers the results of the analysis in the form of a morphological table and TRIZ–evolutionary map. The research defined the most promising in predicting energy flows are hybrid models that include more than one architecture. For example, DCNN + LSTM or MLP + LS–SVR. The authors intend to continue research in the direction of creating predictive models of wind energy flows for autonomous hybrid energy systems.
Practical Aspects of Modernization of Electrical Equipment of the Substation
Authors: Bodrug N S , Skripko O V
Published: November 2021

Currently, one of the important problems for domestic energy is the replacement of an outdated fleet of equipment at substations of electric power systems (EPS). The paper addressed the issue of upgrading the "Ice" substation in part of the selection of switches, checking the reliability of switches and the reliability of the substation in general. The substation characteristic is given, the changes in the main scheme of the substation electrical connections are substantiated, switches for all substation voltages are selected according to the current short circuit currents. To assess the degree of reliability of the selected switches, the substation is determined by their probability of refusal. Based on the assessment of the likelihood of failures and other equipment for the substation, the estimated time of trouble-free operation was determined, the average time of trouble-free operation and the average substation recovery time.
DDoS Protection Method for Servers
Authors: Fedorov V Kh , Balenko E G , Vershennik E V , Zakalkin P V
Published: November 2021

Cyberspace, a global artificial space, has emerged and become part of all human activities, which exposes communication network elements, in particular service servers, to attacks, whether from individual hackers and cyberterrorists or from organized communities. Denial-of-service or DDoS attacks are the most common type. These are intended solely to cause a denial of service in various information systems, including service servers. This paper presents a method that can improve protection of servers that provide various resources (services) by reasonable management of filter rules and IP address lists.
Four-dimensional Integral Model of Dry Friction on the Example of Wheel Movement
Authors: Salimov M S , Saypulaev G R , Merkuriev I V
Published: November 2021

A four-dimensional model of dry friction in the interaction of a solid wheel and a horizontal rough surface is investigated. It is assumed that there is no separation between the wheel and the horizontal surface. The movement of the body occurs in conditions of combined dynamics, when in addition to the sliding movement, the body participates in spinning and rolling. The equation of motion of the wheel is compiled using the Appel equation.

The resulting model of sliding, spinning, and rolling friction is given for the case where the contact area is a circle. The cumbersome integral expressions were replaced by fractional-linear Pade approximations. Pade approximations accurately describe the behavior of the components of the friction model. A mathematical model is proposed that describes the simultaneous sliding, spinning and rolling of a solid wheel. The dependences of the parallel and perpendicular components of the friction force and the torque of the spinning friction were ploted with respect to the parameter that characterizes the movement of the wheel. Comparisons of the integral friction model and the model based on Pade approximations are presented. The results of the comparison showed a qualitative correspondence of the models. After obtaining the equation of motion, the simulation of motion at a constant control torque of the wheel is carried out. The graphs allow you to match the logical behavior of the wheel
movement.
Adaptation Parameters of Time Series Models for Forecasting
Authors: Klevtsov S I , Maksimov A V
Published: November 2021

Prospects for using time series to predict changes in technical parameters in real time are considered. The task is to assess the trend dynamics of the parameter. Adaptive polynomial models of the first and second order, based on the method of multiple exponential smoothing, were selected for forecasting. The models have been modified to adapt to the peculiarities of the computing process in the microcontroller. The initial data, the acceleration values in three axes, were obtained using a three-axis accelerometer installed on the vehicle. Comparison of the forecasting results showed that the second-order adaptive polynomial model is generally more preferable from the point of view of the reduced error. Both models can be used to estimate the change in a parameter for an arbitrary number of prediction intervals. The efficiency of using the models for the forecasting problem largely depends on the determination of the adaptation parameters, such as the smoothing constant and the initial estimates of the coefficients of the time series model. The paper considers the features of the behavior of the models and defines the rules for the selection of adaptation parameters depending on the nature of the change in the technical parameter over time.
Energy Efficiency of Buildings in Arctic Regions of the Russian Federation
Authors: Kuznetsov N , Morozov I
Published: November 2021

This article considers a pressing issue to be addressed by those responsible for the energy efficiency management in the Arctic Regions of the Russian Federation. It presents examples of successful solutions to related problems that can be used by energy efficiency program developers in specific regions. This article reviews the introduction indicators for energy-efficient technologies and the specific consumption values for thermal energy. The monitoring of energy-saving and improvement of energy efficiency across the economic sectors is performed using the specific consumption values of fuel and energy resources. The main causes of the excessive consumption of thermal energy include the maladjustment of heating systems, excessive consumption of hot water in hot water supply systems, low heat-proof properties of the structural surfaces of buildings, and heat losses during heat carrier transport due to the low quality of pipeline insulation.
Resolving of Overlapping Asymmetrical Chromatographic Peaks by Using Wavelet-Transform and Gram-Charlier Peak Model
Authors: Bochkarev A V
Published: November 2021

The paper describes a method for resolving overlapping asymmetric peaks that make up a chromatogram. The presented method uses the Gram-Charlier model in the form of the first three terms of the Gram-Charlier series as a basis. Using the wavelet transform, the parameters of this model are determined, which is used to describe a single or overlapping chromatographic peak. Hermitian wavelets of the first four orders are used in the computation of the wavelet transform. To speed up the computation of multiple wavelet transforms, the possibility of coding a signal using the Chebyshev-Hermite functions is considered in order to further restore the set of wavelet transforms simultaneously. According to the presented method, the parameters of the peaks are determined by analytical expressions without using the numerical approximation of the chromatogram by the peak model, which avoids the disadvantages of the numerical approach. The resulting method is used to resolve overlapping asymmetric peaks. The advantage of the method over others is shown by calculating the area of each of the resolved peaks.
Organizing Interactions Between a Robotic Manipulator and a Technological Equipment Control Panel
Authors: Kim N V , Zhidkov V N , Polyansky V V
Published: November 2021

Algorithms for the organization of standalone operation of a robotic manipulator have been considered in this Article. The controls on the control panel of a man-made equipment piece have been the manipulated object. A robotic manipulator fitted with a control system, and a machine vision system, have been the subsystems under study. The robotic manipulator interacts with the objects to switch on and off a toggle switch, turn a rotary switch, press on a pushbutton, etc. Manipulating the objects in question involves assessing of their positions and orientations, which is achieved through the machine vision system. Coordinated operation of the subsystems is required to plan and to implement control of the manipulator, while taking into account positions of the objects relative to each other. A configuration of interactions between the manipulator and the control panel, a method for organizing coordinated functioning of the machine vision system when manipulating controls, which includes assessing positions of the object of interest relative to the robotic manipulator, and an algorithm for planning control based on artificial neural network technology have been presented in this Article.
The Transition to Energy Efficient Biomass Torrefaction Technology
Authors: Shevchenko A L , Sytchev G A , Zaichenko V M
Published: November 2021

Torrefaction or low-temperature pyrolysis makes it possible to obtain high-quality solid biofuel from various types of biomass (peat, wood and agricultural waste, various types of biowaste) for the needs of distributed energy. The creation of energy supply systems based on local fuel and energy resources is a priority task for Russian Federation. The article presents the results of research on the development of a new method for energy utilization of biomass by torrefaction.
Development of the Test Bed for Experimental Investigation of Autonomous Current Supply System
Authors: Chubraeva L I , Timofeyev S S
Published: November 2021

The test bed is intended for investigations of autonomous current supply system and its individual units and testing of the correspondence of the system to the demands of the wind power alternator with high-temperature superconductive field winding. The test bed configuration is based on module principles thus accelerating the adapting of experimental equipment for quite definite tasks. The test bed contains serial equipment and a number of units specially developed for the definite test program. Some of specially developed modules are presented in the paper.
Formation of Scientific Foundations of Technosphere Safety Among Students of the Direction of Training "Electric Power and Electrical Engineering”
Authors: Bulgakov A B , Vashchuk S P , Panshin R A
Published: November 2021

The article deals with issues related to the formation of scientific foundations of technosphere safety in the training of students and specialists in the field of electric power industry. Technosphere safety in the field of electric power engineering should be formed on the theoretical basis of the subjects of ecology and life safety.
The New Directions on Development of Renewable Energy Systems
Authors: Nefedova L V , Solovyev D A , Bushuev V V , Zaicheneko V M
Published: November 2021

In this article, the authors offer their assessment of the current state and ways of development of electricity and heat generation systems in the world and the Russian Federation, considering the development prospects of renewable energy systems. The results of neural prediction based on the correlation of a set of heterogeneous data inputs are presented. Forecasting and comparing of renewable energy sources and other energy sources makes it possible to identify their strengths and weaknesses and find their optimal combinations in the overall structure of the future energy sector.