bluuebunny/crossref_metadata_2025 huggingface dataset:
Transfer learning for fluence map prediction in adrenal stereotactic body radiation therapy
Authors: Wang Wentao , Sheng Yang , Palta Manisha , Czito Brian , Willett Christopher , Yin Fang-Fang , Wu Qiuwen , Ge Yaorong , Wu Q Jackie
Published: November 2021

Objective: To design a deep transfer learning framework for modeling fluence map predictions for stereotactic body radiation therapy (SBRT) of adrenal cancer and similar sites that usually have a small number of cases. Approach: We developed a transfer learning framework for adrenal SBRT planning that leverages knowledge in a pancreas SBRT planning model. Treatment plans from the two sites had different dose prescriptions and beam settings but both prioritized gastrointestinal sparing. A base framework was first trained with 100 pancreas cases. This framework consists of two convolutional neural networks (CNN), which predict individual beam doses (BD-CNN) and fluence maps (FM-CNN) sequentially for 9-beam intensity-modulated radiation therapy (IMRT) plans. Forty-five adrenal plans were split into training/validation/test sets with the ratio of 20/10/15. The base BD-CNN was re-trained with transfer learning using 5/10/15/20 adrenal training cases to produce multiple candidate adrenal BD-CNN models. The base FM-CNN was directly used for adrenal cases. The deep learning (DL) plans were evaluated by several clinically relevant dosimetric endpoints, producing a percentage score relative to the clinical plans. Main results: Transfer learning significantly reduced the number of training cases and training time needed to train such a DL framework. The adrenal transfer learning model trained with 5/10/15/20 cases achieved validation plan scores of 85.4/91.2/90.7/89.4, suggesting that model performance saturated with 10 training cases. Meanwhile, a model using all 20 adrenal training cases without transfer learning only scored 80.5. For the final test set, the 5/10/15/20-case models achieved scores of 73.5/75.3/78.9/83.3. Significance: It is feasible to use deep transfer learning to train an IMRT fluence prediction framework. This technique could adapt to different dose prescriptions and beam configurations. This framework potentially enables DL modeling for clinical sites that have a limited dataset, either due to few cases or due to rapid technology evolution.
A novel method to assess the spatiotemporal image quality in fluoroscopy
Authors: Monnin P , Viry A , Damet J , Nowak M , Vitzthum V , Racine D
Published: November 2021

Objectives. The planar formulation of the noise equivalent quanta (NEQ) and detective quantum efficiency (DQE) used to assess the image quality of projection images does not deal with the influence of temporal resolution on signal blurring and image noise. These metrics require correction factors based on temporal resolution when used for dynamic imaging systems such as fluoroscopy. Additionally, the standard NEQ and detector DQE are determined on pre-processed images in scatter-free conditions for effective energies produced by additional aluminium or copper filters that are not representative of clinical fluoroscopic procedures. In this work, we developed a method to measure ‘frame NEQ’ and ‘frame system DQE’ which include the temporal frequency bandwidth and consider the anti-scatter grid, the detector and the image processing procedures for beam qualities with scatter fractions representative of clinical use. Approach. We used a solid water phantom to simulate a patient and a thin copper disc to measure the spatial resolution. The copper disc, set in uniform rectilinear motion in the image plane, assessed the temporal resolution. These new metrics were tested on two fluoroscopy systems, a C-arm and a floor-mounted cardiology, for multiple parameters: phantom thicknesses from 5 to 20 cm, frame rates from 3 to 30 fps, spatial and temporal image processing of different weights. Main results. The frame NEQ correctly described the image quality for different scatter conditions, temporal resolutions and image processing techniques. The frame system DQE varied between 0.38 and 0.65 within the different beam and scatter conditions, and correctly mitigated the influence of spatial and temporal image processing. Significance. This study introduces and validates an unbiased formulation of in-plane NEQ and system DQE to assess the spatiotemporal image quality of fluoroscopy systems.
One dimensional reduced model for ITER relevant energetic particle transport
Authors: Carlevaro N , Meng G , Montani G , Zonca F , Hayward-Schneider T , Lauber Ph. , Lu Z , Wang X
Published: November 2021

We set up a mapping procedure able to translate the evolution of the radial profile of fast ions, interacting with toroidal Alfvén Eigenmodes, into the dynamics of an equivalent one-dimensional bump-on-tail system. We apply this mapping technique to reproduce the relevant ITER simulations, which clearly outline deviations from the diffusive quasi-linear (QL) model. Our analysis demonstrates the capability of the one-dimensional beam-plasma dynamics to predict the relevant features of the non-linear hybrid LIGKA/HAGIS simulations. In particular, we clearly identify how the deviation from the QL evolutive profiles is due to the presence of avalanche processes. A detailed analysis regarding the reduced dimensionality is also addressed, by means of phase-space slicing based on constants of motion. In the conclusions, we outline the main criticalities and outcomes of the procedure, which must be satisfactorily addressed to make quantitative predictions on the observed outgoing fluxes in a Tokamak device.
Novel features of electromagnetic waves in an isotropic degenerate electron-ion plasma
Authors: Maryam P , Rozina Ch , Ali S , Shah H A , Poedts S
Published: November 2021

Within the framework of kinetic theory, the nonlinear interaction of electromagnetic waves (EMWs) with a degenerate electron-ion plasma is studied to account for the electron quantum mechanical effects. For this purpose, a specific quantum regime is considered, for which the degenerate electron Fermi velocity is assumed to be of the order of the group velocity of EMWs. This eventually leads to the existence of a nonlinear Landau damping rate for the EMWs in the presence of electron ponderomotive force. The electron–ion density oscillations may have arisen from the nonlinear interaction of EMWs, leading to a new type of nonlinear Schrödinger equation in terms of a complex amplitude for electromagnetic pump waves. The profiles of nonlinear damping rates reveal that EMWs become less damped for increasing the quantum tunneling effects. The electrostatic response of the linear electrostatic waves is also investigated and derived from a linear dispersion for the ion-acoustic damping rate. The latter is a direct function of the electron Fermi speed and does not rely on the Bohm tunneling effect. The obtained results are numerically analyzed for two microwaves of different harmonics in the context of nonrelativistic astrophysical dense plasma environments, e.g. white dwarfs, where the electron quantum corrections cannot be ignored.
Relationships between arc plasma jet properties and plasma/liquid interaction mechanisms for the deposition of nanostructured ceramic coatings
Authors: Rat V , Bienia M , Dhamale G D , Mavier F , Ruelle C , Goutier S
Published: November 2021

Ceramic nanostructured coatings with intermediate thicknesses between 10 and 100 µm give improved thermal and mechanical properties when used as thermal barrier coatings or wear-resistant coatings. Such coatings comply with the technical requirements of aeronautical and automotive applications. This implies the development of deposition processes with high throughput and deposition rates to promote the formation of nanostructured coatings. The use of a liquid phase as a carrier medium for nanoparticles or solution precursors is of major interest for injection within a thermal plasma jet. The as-sprayed materials can form ceramic nanostructured coatings provided the liquid injection, encompassing the physicochemical properties of the liquid and its injection method, can withstand the plasma properties. The repeatability of the interaction phenomena between the liquid phase and the arc jet has a key role in the efficiency of deposition, and some research efforts are devoted to stabilizing the arc while the liquid jet is continuously injected within the plasma. Alternatively a pulsed arc plasma jet can be generated and is associated with a time-phased injection of droplets. This paper presents the different issues related to the arc plasma properties produced by direct plasma torches, including arc instabilities and their influence on plasma/liquid interaction mechanisms leading to the formation of nanomaterials. There is a focus on pulsed plasma spraying associated with synchronized injection of microsized droplets by means of an inkjet printing method.
Calculation of discrete and resonant states of Coulomb acceptor in HgCdTe alloys
Authors: Zholudev M S , Rumyantsev V V , Morozov S V
Published: November 2021

The energies and wavefunctions of both localized and resonant states are calculated for Coulomb acceptor in narrow-gap HgCdTe alloys with cadmium mole fraction from 0% to 30%. The simulation is performed with scattering matrix method within a spherically-symmetric three-band Kane model that takes into account the conduction band and two valence bands. The energies of both localized and resonant states are determined using the localization rate magnitude, introduced in this work.
Electrical-stress driven oxidation in 940 nm oxide-confined VCSEL
Authors: Pusterhofer Michael , Fabbro Robert , Coppeta Raffaele A , Fasching Gernot , Hadley Peter
Published: November 2021

In this work, accelerated stress tests have been performed on oxide confined vertical cavity surface emitting LASER arrays to study the formation of defects degrading the performance of the device. One such defect is an additional oxide volume forming at the oxide aperture edge, which is used for optical and electrical confinement. After producing an additional oxide volume the sample was investigated using transmission electron microscopy to estimate the oxidation speed. To produce further insights into the formation process, the temperature during such a stress test was estimated by experimentally measuring the thermal resistance, and by a thermodynamic transport simulation. Both methods produced very similar results showing a temperature increase of around 22 K for a dissipated power of 3.5 mW per emitter. However this temperature rise is very small when compared to oxidation models found in literature and should not be enough to promote the oxidation. This indicates the presence of a new enhanced oxidation mechanism, which could be connected to corrosion based failure mechanisms reported in literature.
An asymmetric magnetic-coupled bending-torsion piezoelectric energy harvester: modeling and experimental investigation
Authors: Zhang Huirong , Sui Wentao , Yang Chongqiu , Zhang Leian , Song Rujun , Wang Junlei
Published: November 2021

This paper presents a detailed investigation on an asymmetric magnetic-coupled bending-torsion piezoelectric energy harvester based on harmonic excitation. There is an eccentricity between the shape center of moving magnets and the axis of the piezoelectric beam, which results in the bending and torsion simultaneously in working condition. The distributed mathematical model is derived from the energy method to describe the dynamic characteristics of the harvester, and the correctness of the model is verified by experiments. To further demonstrate the improvement performance of the proposed energy harvester, the bending-torsion energy harvester (i.e. magnetic-coupled was not configured) is experimented and compared. The theoretical and experimental results indicate that the average power increases about 300% but the resonance frequency decreases approximately 2 Hz comparing to the harvester without magnetic-coupled. According to the characteristic of distributed parameter model, the magnetic force and the size of the piezoelectric beam are investigated respectively. And the lumped-parameter model is introduced to analyze the steady-state characteristic. Accordingly, this paper provides a feasible method to improve performance for piezoelectric energy harvester.
Study on sliding friction characteristics of magnetorheological elastomer—copper pair affected by magnetic-controlled surface roughness and elastic modulus
Authors: Li Rui , Wang Di , Li Xinyan , Liao Changrong , Yang Ping-an , Ruan Haibo , Shou Mengjie , Luo Jiufei , Wang Xiaojie
Published: November 2021

To optimize the online friction coefficient adjustment, it is necessary to study the parameter change features of the magneto-sensitive polymer and its influence on the friction characteristics under magnetic field. A series of magnetorheological elastomers (MREs) with different initial surface roughness were prepared, and a sliding friction platform with MRE—copper block pair was built to carry out magnetic-controlled friction characteristic experiment. Results show that the sliding friction coefficient of MRE decreases with the increase of the magnetic field, but the degree of reduction is quite different under different initial surface roughness and elastic modulus. When the initial surface roughness of MRE is between 0.5 and 2.5 μm and the carbonyl iron particles volume fraction is between 10% and 15%, its magnetic-controlled friction coefficient has the largest reduced value of 22.75%. Moreover, features of elastic modulus and surface topography under magnetic field were tested and analyzed. By combining with the single peak contact model and the friction binomial law, the relationship between the surface roughness and elastic modulus of MREs and the sliding friction force is deduced, and it is proved that the friction coefficient is affected by the coupling effect of surface roughness and elastic modulus. The magnetic-controlled elastic modulus is the key factor, which determines the overall downward trend of the friction coefficient of MREs. Magnetic-controlled surface roughness also plays an important role in the adjustable range of friction coefficient, and reducing the initial surface roughness can increase the magnetic-controlled friction coefficient adjustable range.
High sensitivity and broad detection range flexible capacitive pressure sensor based on rGO cotton fiber for human motion detection
Authors: Zheng Rongliang , Wang Youyuan , Zhang Zhanxi , Zhang Yanfang , Liu Jinzhan
Published: November 2021

Recently, flexible pressure sensors have attracted considerable interest in electronic skins, wearable devices, intelligent robots and biomedical diagnostics. However, the design of high sensitivity flexible pressure sensors often relies on expensive materials and complex process technology, which greatly limit their popularity and applications. Even worse, chemical-based sensors are poorly biocompatible and harmful to the environment. Here, we developed a flexible capacitive pressure sensor based on reduced graphene oxide cotton fiber by a simple and low-cost preparation process. The environmentally friendly sensor exhibited a comprehensive performance with not only ultra-high sensitivity (up to 15.84 kPa−1) and a broad sensing range (0–500 kPa), but also excellent repeatability (over 400 cycles), low hysteresis (⩽11.6%), low detection limit (<0.1 kPa) and wide frequency availability (sensitivity from 19.71 to 11.24 kPa−1, frequency from 100 Hz to 10 kHz). Based on its superior performance, the proposed sensor can detect various external stimuli (vertical stress, bending and airflow) and has been successfully applied for facial expression recognition, breathing detection, joint movement and walking detection, showing great potential for application in artificial electronic skin and wearable healthcare devices.
Life-cycle health monitoring of composite structures using piezoelectric sensor network
Authors: Yu Yinghong , Liu Xiao , Li Jun , Wang Yishou , Qing Xinlin
Published: November 2021

The vacuum-assisted resin infusion (VARI) technique provides considerable advantages in manufacturing large-scale composite structures. An accurate and consecutive structural health monitoring system is urgently required to determine the initial quality and assess the structural integrity of a composite structure. In this paper, a real-time active smart diagnostic system (SDS) based on piezoelectric sensor network is proposed to monitor the whole life-cycle of composite structures. Experiments were conducted on carbon fiber reinforced plastic specimens with different thicknesses to investigate the monitoring capability of piezoelectric lead-zirconate-titanate (PZT) sensors used in the SDS approach. The PZT sensor networks inserted inside the composite structures during the VARI process are used to monitor not only the curing parameters, but also the health status of composite structures when they are in service after curing. To monitor the curing process only, the sensor network can also be installed on the bottom of the mould. Experimental results demonstrate that both 3D resin flow and degree of cure in the VARI process can be effectively monitored by the PZT sensor network. Meanwhile, the embedded PZT sensor network has the potential to identify the different stages in the curing process. It is obvious that the piezoelectric sensor network will provide important technical support for composite materials with the structure and function integrated.
Detailed study of quantum path interferences in high harmonic generation driven by chirped laser pulses
Authors: Csizmadia Tamás , Gulyás Oldal Lénárd , Ye Peng , Majorosi Szilárd , Tzallas Paraskevas , Sansone Giuseppe , Tosa Valer , Varjú Katalin , Major Balázs , Kahaly Subhendu
Published: November 2021

We investigate the electron quantum path interference (QPI) effects during high harmonic generation in atomic gas medium driven by ultrashort chirped laser pulses. To achieve that, we identify and vary the different experimentally relevant control parameters of such a driving laser pulse influencing the high harmonic spectra. Specifically, the impact of the pulse duration (from the few-cycle to the multi-cycle domain), peak intensity and instantaneous frequency is studied in a self-consistent manner. Simulations involving macroscopic propagation effects are also considered. The study aims to reveal the microscopic background behind a variety of interference patterns capturing important information both about the fundamental laser field and the generation process itself. The results provide guidance towards experiments with chirp control as a tool to unravel, explain and utilize the rich and complex interplay between QPIs including the tuning of the periodicity of the intensity dependent oscillation of the harmonic signal, and the curvature of spectrally resolved Maker fringes.
Prograde and retrograde precession of a fluid-filled cylinder
Authors: Pizzi Federico , Giesecke André , Šimkanin Ján , Stefani Frank
Published: November 2021

We numerically study precession driven flows in a cylindrical container whose nutation angle varies between 60 and 90 degrees for prograde and retrograde precession. For prograde precession we observe sharp transitions between a laminar and a turbulent flow state with low and high geostrophic axisymmetric flow components related with a centrifugal instability, while for retrograde precession a rather smooth transition between a low state and a high state occurs. At the same time prograde and perpendicular precession shows an abrupt breakdown of the flow directly excited by the forcing mechanism, which is not the case for retrograde motion. We characterize the corresponding flow states in terms of the directly driven, non-axisymmetric Kelvin mode, the axisymmetric geostrophic mode, and an axisymmetric poloidal flow which is promising for precession-driven dynamo action. The latter issue is discussed with particular view on an optimal parameter choice for the DRESDYN dynamo project.
Eternally non-Markovian dynamics of a qubit interacting with a single-photon wavepacket
Authors: Dąbrowska Anita , Chruściński Dariusz , Chakraborty Sagnik , Sarbicki Gniewomir
Published: November 2021

An evolution of a two-level system (qubit) interacting with a single-photon wave packet is analyzed. It is shown that a hierarchy of master equations gives rise to phase covariant qubit evolution. The temporal correlations in the input field induce nontrivial memory effects for the evolution of a qubit. It is shown that in the resonant case whenever time-local generator is regular (does not display singularities) the qubit evolution never displays information backflow. However, in general the generator might be highly singular leading to intricate non-Markovian effects. A detailed analysis of the exponential profile is provided which allows to illustrate all characteristic feature of the qubit evolution.
Corrigendum: Concise and tight security analysis of the Bennett–Brassard 1984 protocol with finite key lengths (2012 New J. Phys.
14
093014)
Authors: Hayashi Masahito , Tsurumaru Toyohiro
Published: November 2021

The paper (Hayashi M and Tsurumaru T 2012 New J. Phys.
14
093014) contains an error at the definition of g

t
(x) in section 5.3 while g

t
(x) is used for the second order asymptotic expansion for the sacrifice bit. This corrigendum corrects this error and shows its derivation.
Flicker noise in two-dimensional electron gas
Authors: Najafi M N , Tizdast S , Moghaddam Z , Samadpour M
Published: November 2021

Using the method developed in a recent paper (2019 Euro. Phys. J.
B
92 1–28) we consider 1/f noise in two-dimensional electron gas (2DEG). The electron coherence length of the system is considered as a basic parameter for discretizing the space, inside which the dynamics of electrons is described by quantum mechanics, while for length scales much larger than it the dynamics is semi-classical. For our model, which is based on the Thomas-Fermi–Dirac approximation, there are two control parameters: temperature T and the disorder strength (Δ). Our Monte Carlo studies show that the system exhibits 1/f noise related to the electronic avalanche size, which can serve as a model for describing the experimentally observed flicker noise in 2DEG. The power spectrum of our model scales with the frequency with an exponent in the interval 0.3 < α

PS
< 0.6. We numerically show that the electronic avalanches are scale-invariant with power-law behaviors in and out of the metal-insulator transition line.
Resonant tunneling in natural photosynthetic systems
Authors: Gerodias Kit M , Bernido Maria Victoria Carpio , Bernido Christopher C
Published: November 2021

The high internal quantum efficiency observed in higher plants remains an outstanding problem in understanding photosynthesis. Several approaches such as quantum entanglement and quantum coherence have been explored. However, none has yet drawn an analogy between superlattices and the geometrical structure of granal thylakoids in leaves. In this paper, we calculate the transmission coefficients and perform numerical simulations using the parameters relevant to a stack of thylakoid discs. We then show that quantum resonant tunneling can occur at low effective mass of particles for 680 nm and 700 nm incident wavelengths corresponding to energies at which photosynthesis occurs.
Solar rotational period of cosmic rays and solar activity during the maximum phase of solar cycle 24
Authors: Singh P R , Farid A I Saad , Singh Y P , Singh A K , Aly Ayman A
Published: November 2021

To study the solar rotational oscillation on daily averaged time series of solar activity proxies: sunspot number (SSN), modified coronal index (MCI), solar flare index (FI), and cosmic ray intensity (CRI) are subjected to Lomb/Scargle periodogram, and continuous wavelet transform. For this purpose, we have used data of all the considered parameters from 2012 to 2015, which covers the maximum phase including the polarity reversal period of the solar cycle 24. Both spectral analysis techniques are carried out to study the behavior of 27-days on the time scale of the synodic period and to follow their evolution throughout the epoch. Further, we have used R package RobPer (least square regression) techniques and obtained a significant true period ∼27 days is present in this study. It is noted that the ∼27-day period of solar activity parameters and cosmic rays is much prominent during the examined period.
Scalar and tensor perturbations in DHOST bounce cosmology
Authors: Zhu Mian , Ilyas Amara , Zheng Yunlong , Cai Yi-Fu , Saridakis Emmanuel N.
Published: November 2021

We investigate the bounce realization in the framework of
DHOST cosmology, focusing on the relation with observables. We
perform a detailed analysis of the scalar and tensor perturbations
during the Ekpyrotic contraction phase, the bounce phase, and the
fast-roll expansion phase, calculating the power spectra, the
spectral indices and the tensor-to-scalar ratio. Furthermore, we
study the initial conditions, incorporating perturbations generated
by Ekpyrotic vacuum fluctuations, by matter vacuum fluctuations, and
by thermal fluctuations. The scale invariance of the scalar power
spectrum can be acquired introducing a matter contraction phase
before the Ekpyrotic phase, or invoking a thermal gas as the
source. The DHOST bounce scenario with cosmological perturbations
generated by thermal fluctuations proves to be the most efficient
one, and the corresponding predictions are in perfect agreement with
observational bounds. Especially the tensor-to-scalar ratio is many
orders of magnitude within the allowed region, since it is
suppressed by the Hubble parameter at the beginning of the bounce phase.
Onset of flow instability with one-side heated swirl tube for fusion reactor safety
Authors: Lim Ji Hwan , Lee Su Won , Oh Hoongyo , Park Minkyu , Hwang Donkoan , Kim Moo Hwan , Jo HangJin
Published: November 2021

In this study, the onset of flow instability (OFI) heat flux of a one-side heated swirl tube is experimentally investigated. The OFI heat flux means the minimum heat flux that can cause flow instability by the vapor generated in the flow path. An analysis of the effect of system parameters on the OFI heat flux indicates that as the pressure increases, the bubble size decreases. Therefore, the void fraction decreases and, consequently, the OFI heat flux tends to increase. Similarly, the higher the flow rate and degree of subcooling, the faster the vapor can be removed; thus, the OFI heat flux increases. In addition, the prediction performances of the existing OFI correlations developed under the subcooled flow-boiling condition are evaluated. Therefore, although the Wang correlation indicates the lowest error rate, it yields a high mean absolute error rate of 87.75%. Thus, it is difficult to predict the OFI heat flux of a one-side heated swirl tube using the existing OFI correlations. Therefore, in this study, a new correlation is developed using a Python code created by employing an artificial intelligence regression method. The developed correlation incorporates the impact of one-side heating, swirl tape, mass flow rate, subcooling, and pressure (mean absolute error = 12.17%, root mean square error = 14.99%).
Plasma-wall self-organization in magnetic fusion
Authors: Escande D.F. , Sattin F. , Zanca P.
Published: November 2021

This paper introduces the concept of plasma-wall self-organization (PWSO) in magnetic fusion. The basic idea is the existence of a time delay in the feedback loop relating radiation and impurity production on divertor plates. Both a zero and a one-dimensional description of PWSO are provided. They lead to an iterative equation whose equilibrium fixed point is unstable above some threshold. This threshold corresponds to a radiative density limit, which can be reached for a ratio of total radiated power to total input power as low as 1/2. When detachment develops and physical sputtering dominates, this limit is progressively pushed to very high values if the radiation of non-plate impurities stays low. Therefore, PWSO comes with two basins for this organization: the usual one with a density limit, and a new one with density freedom, in particular for machines using high-Z materials. Two basins of attraction of PWSO are shown to exist for the tokamak during start-up, with a high density one leading to this freedom. This basin might be reached by a proper tailoring of ECRH assisted ohmic start-up in present middle-size tokamaks, mimicking present stellarator start-up. In view of the impressive tokamak DEMO wall load challenge, it is worth considering and checking this possibility, which comes with that of more margins for ITER and of smaller reactors.
Combining the Pre-Distribution Key Protocol with the Threshold Scheme
Authors: Belim S V , Belim S Y
Published: November 2021

In the article, the protocol for key pre-distribution using a threshold scheme is proposed. The Blom pre-distribution scheme is used as the basis. Shamir secret sharing scheme is used for threshold scheme. A polynomial of three variables is used to form key materials. Messaging between users is required to generate a key. The threshold scheme (3,4) is used to calculate the encryption key.
Methods of Electrodynamic Modelling for Reflector Antennas
Authors: Ischenko E A , Fedorov S M , Barannikov I A
Published: November 2021

The article discusses methods for calculating the electromagnetic characteristics of reflector antennas based on the finite integration method, the method of moments, and the hybrid method. In the course of the study, a performance comparison of these methods in the process of calculating the reflector antenna characteristics was made. Comparison of the calculation efficiency was carried out using four computing devices. On the basis of the calculations, the graphs of the scattering matrix and the directional diagrams of the antenna under study were obtained
Pipe Welding Machine Modernization
Authors: Frolov A V
Published: November 2021

There are the results of pipelines rolled joints welding machine modernization. The machine is designed using a welding rotator, linear electric drives, stepper motors, CNC system. The machine is controlled by a CNC system according to ISO 6983-1: 2009. The machine consists of: stepping rotary device, welding torch stepping device, controlled TIG welding power source, controlled welding wire feeder, welding current control system, workpiece rotation control system and welding torch. The welding torch movement trajectory controlling software has been created. It allows to weld by any type of welding torch recommended movements. The modernizing machine allows welding the pipelines rolled joints in automatic mode both in one pass and in multi-pass. The machine can be used for industrial pipeline elements welding, for welding modes testing, for studying the effect of welding modes on the quality of pipeline welds. The results can be adapted for sheet structures welding using the standard commands of the ISO 6983-1: 2009 standard. The results can be adapted to industrial welding robots control. The welding machine can be used for MIG / MAG welding and surfacing.
Development of an Information System for the Distance Learning Process Organization
Authors: Obukhov A , Volkov A , Maistrenko N
Published: November 2021

The article describes the process of creating a personal account system for correspondence students, starting with the study of the issue as a whole and ending with the process of developing one of the main components of the information system. The process of creating an IS includes such stages as: determining the required functionality, designing the overall architecture of the system and each of its components. The technologies and software solutions used to system implementation are described, as well as the method of integrating the created solution with the existing information infrastructure of the educational institution. A brief mathematical description of one of the tasks solved by the information system, automated schedule generation, is also given.
Development of a Visualization System for a Virtual Laboratory for Training Personnel of Industrial Enterprises
Authors: Arkhipov A , Prokudina N , Patutin K
Published: November 2021

An urgent task in the training of personnel of industrial enterprises is the development of the required amount of practical skills. In the context of a pandemic, restrictive measures, as well as the high cost and danger of conducting training on real equipment, virtual laboratories are becoming one of the most promising training tools. The virtual laboratory includes a visualization system (many 3D objects, animations and effects), as well as software components, databases, modules for logging and assessing the quality of exercise performance. Within the framework of this work, the task of developing a visualization system for virtual laboratories is considered. A structural diagram of the visualization system is proposed, illustrating all the necessary elements for creating virtual stands, an implementation algorithm is drawn up. The software implementation is described on the example of a laboratory setup for performing the Reynolds experiments.
Model for Assessing the Immunity of Channels Using Frequency Manipulation Signals
Authors: Fedorov V K , Balenko E G , Dvornikov S V , Lauta O S
Published: November 2021

The issues of noise immunity of control channels of robotic systems using signals with frequency shift keying are considered. The article presents the results of estimating the probability of a bit error depending on the duration of the intervals at which the time coincidence of the structural interference with the signal occurs. Proposals are formulated for the practical use of the results obtained.
Testing Platform Invoke as a Tool for Shellcode Injection in Windows Applications
Authors: Fedorov V K , Balenko E G , Gololobov N V , Izrailov K E
Published: November 2021

This paper investigates software attacks based on shellcode injection in Windows applications. The attack uses platform invoke to inject binary code by means of system calls. This creates a separate threat that carries the payload. The paper overviews protections against shellcode injection and thus analyzes the injection methods as well. Analysis models the injection of malicious code in a Windows app process. As a result, the paper proposes a step-by-step injection method. Experimental injection of user code in PowerShell is performed to test the method. The paper further shows the assembly code of the system call as an example of finding their IDs in the global system call table; it also shows part of the source code for the injection of binary executable code. Various counterattacks are proposed in the form of software control modules based on architecture drivers. The paper analyzes the feasibility of using dynamic invoke, which the authors plan to do later on.
Measurement of Oil Consumption by Turbine Flow Meters in Conditions of Wax Deposition
Authors: Krasnov A N , Prakhova M Yu , Novikova Yu V
Published: November 2021

Commercial metering of oil is performed at almost all stages of the life cycle, from well production control to the transfer of the produced oil to the end customer. In most cases, special systems for measuring the quantity and quality of commercial oil (SIQO) are used for this. If such a system implements an indirect dynamic measurement method, then a turbine flow meter is most often a means of measuring volumetric flow. Its accuracy depends on many external factors, including wax deposits on the inner surface of the measuring pipeline and on the elements of the flow meter itself. The article investigates the influence of the thickness of the paraffin layer on the error value of the turbine flow meter. It is shown that the decrease in metrological reliability occurs mainly due to the appearance of a paraffin layer in the measuring line itself. It is proposed to determine the timing of the metrological characteristics verification by indirect parameters, in particular, by the change in pressure in the measuring line.
Hybrid Decentralized Nonlinear Control System for Manipulation Robot with Input Saturations
Authors: Eremin E L , Nikiforova L V , Shelenok E A
Published: November 2021

The paper is devoted to consideration of the problem of constructing a discrete-continuous decentralized nonlinear combined control system for two-link robotic manipulator with restrictions in control signals. The mathematical model of the manipulator is presented as a two-channel dynamic plant with nonlinear cross-links. As methods for solving this problem V. M. Popov’s hyperstability criterion and the conditions of L-dissipativity are used. With the help of simulation, the quality of the proposed control system is shown. The results obtained in article may be useful for construction the control systems for manipulators with many degrees of freedom and also for control various mechanical systems.
Speech to Text System for Noisy and Quiet Speech
Authors: Kuzmin A , Ivanov S
Published: November 2021

This paper examines one of the available and simple methods to develop speech recognition systems capable of recognizing speech from noisy or silent recordings. Such systems improve the automated operation of call centers, and also bring us closer to creating speech recognition models capable of ignoring the speech deficiencies of speakers.
Optimization of Phase Determining Method for Automatic Transfer Switch Operation Based on Simulated Annealing
Authors: Tikhomirov A A , Sobolev N V
Published: November 2021

Fast reserve supply input systems significantly increase the reliability of power supply due to the possibility of preserving the technological process in case of emergency situations. The accuracy of determining the phase of the residual voltage on the busbar in process of connecting the power reserve supply provides a way to significantly reduce the starting overcurrents. In this paper, some modifications of the annealing method for determining the phase of the residual voltage on main section of busbar for emergency mode are considered. The obtained simulation results based on MATLAB environment make it possible to carry out a comparative analysis of a number of calculations for phase estimation design of automatic transfer switch operations based on simulated annealing.
Centralized Control System of the Flotation Department: Ross-Eshby Principle
Authors: Lednov A V , Logunova O S , Khudyakov P Y , Kukhta Y B
Published: November 2021

The aim of the study is to scientifically substantiate the need to use the axiomatic approach when choosing and studying the processes of centralized dispatching control of technological parameters for a complex of flotation machines. During the research, the au-thors performed: comparison of a real object and its properties with the classical control axioms of system analysis; substantiated the use of a hierarchical structure of interrelated technological parameters and their application for situational management. Methods of classical control axioms of system analysis were used for the research. The authors formu-lated the criteria for situational management, the concept of visualization in the dispatching system. The results obtained allow us to assert that the implementation of the Ross-Ashby principle significantly increases the controllability of technological processes with a large number of units and measured parameters.
Improving the Efficiency of Autonomous Heat Supply Systems by Implementing Integrated Control Systems
Authors: Gordin S A , Sosnin A A , Zaychenko I V
Published: November 2021

In this paper we studied the actuality of the problem of optimal control of the heat supply system as a single complex object on the basis of a generalized mathematical model that takes into account the dynamics of the fuel combustion process, heat generation, its transmission through the heat network and that takes into account the dynamics of heat energy consumption and various external factors.
Algorithms for Detecting and Preventing Attacks on Machine Learning Models in Cyber-Security Problems
Authors: Chukhnov A P , Ivanov Y S
Published: November 2021

Machine learning algorithms can be vulnerable to many forms of attacks aimed at leading the machine learning systems to make deliberate errors. The article provides an overview of attack technologies on the models and training datasets for the purpose of destructive (poisoning) effect. Experiments have been carried out to implement the existing attacks on various models. A comparative analysis of cyber-resistance of various models, most frequently used in operating systems, to destructive information actions has been prepared. The stability of various models most often used in applied problems to destructive information influences is investigated. The stability of the models is shown in case of poisoning up to 50% of the training data.
Modeling of Seasonal Variations of Thermal Energy Production by an Electric Power Company based on Neural Network Technology
Authors: Zhebsain V V , Erdniev O P , Zhebsain T V
Published: November 2021

The paper considers the problem of modeling the dependence of the value of thermal energy production by an electric power company on the air temperature using neural network technology. As an example of an electric power company producing thermal energy, the Public Joint-Stock Company (PJSC) Yakutskenergo. As consumers of thermal energy, organizations, enterprises and the population of the city of Yakutsk, are located at latitude 62 and characterized by a cold northern climate. The numerical experiments carried out in this paper have shown that the general trend of the temperature dependence of thermal energy production, observed empirically, is well described by a neural network
Evaluation of the Diethylene Glycol Regeneration rate in Gas Fields Based on Indirect Measurements
Authors: Krasnov A N
Published: November 2021

Gas dehydration in the field is a mandatory procedure before long-distance transportation. In Russia, gas is dried by absorption using diethylene glycol (DEG). Upon absorbing moisture from the raw gas, DEG is regenerated and recycled to dehydration, the quality of which largely depends on the regeneration rate. This indicator is not measured directly at the dehydration plant, and regeneration is controlled discretely based on the periodic laboratory analysis results. The paper describes a virtual analyzer determining the DEG concentration in a real-time mode based on the temperature and DEG consumption measurement results. The regression mathematical model underlying the virtual analyzer has been built based on experimental data obtained at the Yamburg gas condensate field. As part of the gas treatment plant APCS, a virtual analyzer improves the treatment efficiency and reduces the DEG consumption.
The Assessment of a Magnetizing-Current Inrush of a Power Transformer
Authors: Kuvshinov A , Vakhnina V , Kretov D , Chernenko A
Published: November 2021

The study aims to propose an analytical tool for determining the parameters of the power transformer magnetizing inrush current caused by geomagnetically induced currents flowing through high-voltage windings with a grounded neutral under the impact of geomagnetic disturbances on the power grid. The analytical equations for the instantaneous magnetizing current under geomagnetic disturbances were obtain by mathematical model of magnetizing branch for a shell-type power transformer. A model base on a magnetization characteristics piecewise-linear approximation for the electrical steel. The magnetizing inrush current amplitude and duration it was found depends on the intensity of geomagnetic disturbances and in cope-link with the dynamics of the power transformer core saturation transient process were determined the changes in the magnetizing inrush current amplitude and duration under geomagnetic disturbances. The magnetizing inrush current amplitude it was found may reach the level of short-circuit current periodic component at the point of power transformer grid connection. The results were verify by comparing the design and experimental values of the magnetizing inrush current amplitude. The advantages of proposed mathematical model shown with justifying the analogy between core saturation under connecting of power transformer to a grid and under geomagnetically induced currents exposed. The piecewise-linear approximation of power transformer magnetization characteristic, allow to obtain the amplitude value of magnetizing inrush current caused by geomagnetically induced currents with an accuracy of 6% and can be used with power grid steady state and transient simulation under geomagnetic disturbances.
Analysis of the Transformation of Random Signals and Noise Using Poly-Gaussian Models
Authors: Artyushenko V M , Volovach V I
Published: November 2021

Analysis performed transformation of random signals and noise in linear and nonlinear systems based on the use of poly-Gaussian models and multidimensional PDF of the output paths of information-measuring and radio systems. The classification of elements of these systems, as well as expressions describing the input action and output response of the system are given. It is shown that the analysis of information-measuring and systems can be carried out using poly-Gaussian models. The analysis is carried out with a series connection of a linear system and a nonlinear element, a series connection of a nonlinear element and a linear system, as well as with a parallel connection of the named links. The output response in all cases will be a mixture of a poly-Gaussian distribution with a number of components. An example of the analysis of signal transmission through an intermediate frequency amplifier and a linear detector against a background of non-Gaussian noise is given. The resulting probability density distribution of the sum of the signal and non-Gaussian noise at the output of the detector will be poly-Rice. The multidimensional probability distribution density of the output processes of the nonlinear signal envelope detector is also obtained. The results of modeling the found distribution densities are presented. It is shown that the use of the poly-Gaussian representation of signals and noise, as well as the impulse response of the system, makes it possible to effectively analyze inertial systems in the time domain.
Conversion of DC Armature Winding into Multi-Phase AC Winding
Authors: Chubraeva L I , Timofeyev S S
Published: November 2021

The paper is dedicated to the principles of transformation of a rotating armature of DC machine into a rotating AC armature of a reverse-type AC alternator, which represents finally the major part of a model brushless exciter. The methodology of this conversion is based on main principles of the theory of electrical machines [1, 2].
Simulation of Rare Events in Stochastic Systems
Authors: Kabanov A A , Dubovik S A
Published: November 2021

The paper presents algorithms for simulation rare events in stochastic systems based on the theory of large deviations. Here, this approach is used in conjunction with the tools of optimal control theory to estimate the probability that some observed states in a stochastic system will exceed a given threshold by some upcoming time instant. Algorithms for obtaining controlled extremal trajectory (A-profile) of the system, along which the transition to a rare event (threshold) occurs most likely under the influence of disturbances that minimize the action functional, are presented. It is also shown how this minimization can be efficiently performed using numerical-analytical methods of optimal control for linear and nonlinear systems. These results are illustrated by an example for a precipitation-measured monsoon intraseasonal oscillation (MISO) described by a low-order nonlinear stochastic model.