Class Of Schemes Research Articles

Secure Transmission Over Multiple Access Wiretap Channel by Cross-Time Interference Injection

Due to the openness of wireless communication, information transmitted in the multiple access channel is vulnerable to eavesdropping by illegitimate users. Classic artificial noise-assisted schemes can improve security but are not suitable for power-constrained users. To address this problem, we propose a cross-time interference injection scheme in this paper, which improves security by introducing cross-time self-interference and inter-user interference, and does not require artificial noise. The proposed scheme exploits the properties of the Hadamard matrix and the wireless channels, so that the eavesdropping channel suffers from stronger interference than the legitimate channel. We analyze the security performance when both the legitimate receiver and the eavesdropper exploit the successive interference cancellation (SIC) scheme, including the secrecy sum rate, the secrecy capacity, and the secrecy outage probability. We further investigate the effect of the number of eavesdropper’s antennas, the number of legitimate users, and the number of time slots used by the scheme on the security performance, and obtain the corresponding relationship between these parameters when achieving a positive secrecy rate. Finally, simulation results corroborate our theoretical analysis.

On the comparative performance of fourth order Runge-Kutta and the Galerkin-Petrov time discretization methods for solving nonlinear ordinary differential equations with application to some mathematical models in epidemiology

<abstract><p>Anti-viral medication is comparably incredibly beneficial for individuals who are infected with numerous viruses. Mathematical modeling is crucial for comprehending the various relationships involving viruses, immune responses and health in general. This study concerns the implementation of a <italic>continuous</italic> Galerkin-Petrov time discretization scheme with mathematical models that consist of nonlinear ordinary differential equations for the hepatitis B virus, the Chen system and HIV infection. For the Galerkin scheme, we have two unknowns on each time interval which have to be computed by solving a $ 2 \times 2 $ block system. The proposed method is accurate to order 3 in the whole time interval and shows even super convergence of order 4 in the discrete time points. The study presents the accurate solutions achieved by means of the aforementioned schemes, presented numerically and graphically. Further, we implemented the classical fourth-order Runge-Kutta scheme accurately and performed various numerical tests for assessing the efficiency and computational cost (in terms of time) of the suggested schemes. The performances of the fourth order Runge-Kutta and the Galerkin-Petrov time discretization approaches for solving nonlinear ordinary differential equations were compared, with applications towards certain mathematical models in epidemiology. Several simulations were carried out with varying time step sizes, and the efficiency of the Galerkin and Runge Kutta schemes was evaluated at various time points. A detailed analysis of the outcomes obtained by the Galerkin scheme and the Runge-Kutta technique indicates that the results presented are in excellent agreement with each other despite having distinct computational costs in terms of time. It is observed that the Galerkin scheme is noticeably slower and requires more time in comparison to the Runge Kutta scheme. The numerical computations demonstrate that the Galerkin scheme provides highly precise solutions at relatively large time step sizes as compared to the Runge-Kutta scheme.</p></abstract>

Learning Nonlocal Sparse and Low-Rank Models for Image Compressive Sensing: Nonlocal sparse and low-rank modeling

The compressive sensing (CS) scheme exploits many fewer measurements than suggested by the Nyquist–Shannon sampling theorem to accurately reconstruct images, which has attracted considerable attention in the computational imaging community. While classic image CS schemes employ sparsity using analytical transforms or bases, the learning-based approaches have become increasingly popular in recent years. Such methods can effectively model the structure of image patches by optimizing their sparse representations or learning deep neural networks while preserving the known or modeled sensing process. Beyond exploiting local image properties, advanced CS schemes adopt nonlocal image modeling by extracting similar or highly correlated patches at different locations of an image to form a group to process jointly. More recent learning-based CS schemes apply nonlocal structured sparsity priors using group sparse (and related) representation (GSR) and/or low-rank (LR) modeling, which have demonstrated promising performance in various computational imaging and image processing applications.

On the optimal configuration of a square array group testing algorithm

Up to date, only lower and upper bounds for the optimal configuration of a Square Array (A2) Group Testing (GT) algorithm are known. We establish exact analytical formulae and provide a couple of applications of our result. First, we compare the A2 GT scheme to several other classical GT schemes in terms of the gain per specimen attained at optimal configuration. Second, operating under objective Bayesian framework with the loss designed to attain minimum at optimal GT configuration, we suggest the preferred choice of the group size under natural minimal assumptions: the prior information regarding the prevalence suggests that grouping and application of A2 is better than individual testing. The same suggestion is provided for the Minimax strategy.

EVALUATION OF DISSIPATION ENERGY OF ISOTROPIC CONTINUUM DAMAGE MECHANICS MODEL WITH ADAPTIVE TIME-STEP CONTROL APPROACH

This paper proposes an algorithm to evaluate dissipation energy of an isotropic continuum damage mechanics model with an adaptive time-step control approach. The algorithm takes place at each integration point under the scope of finite element analysis. The total amount of the dissipation energy of one structure can be used to verify the conservation law of energy, where the summation of the elastic strain energy and the dissipation energy should be equal to the total work by external force. However, the paper shows that this condition may not be valid when the unstable crack propagation occurs. When the crack propagation is unstable, the development of damage can be driven by stored strain energy without external load. The strains at the beginning and ending time within one increment at the damaged elements will give inaccurate dissipation energy by the classic trapezoidal integration scheme. In addition, this paper proposes a new damage evolution shape function with C1 continuity of the strain-stress curve under the uniaxial tension test, which is used to demonstrate the numerical procedure of the adaptive algorithm.

The Effects of Classical Chinese Dance Movements on Personal Awareness and Emotion Regulation

This research aims to explore the effectiveness of a Chinese classical dance therapy group on college students’ self-awareness and emotion regulation. A pretest and quasi-experimental design was used for this study, with 172 college students in China as the research object. The experimental group underwent Chinese classical dance therapy twice every week, three hours every time, until eighteen hours later; meanwhile, the control group did not handle or train. Members of the two groups were tested before and after the "Introspection Scale", "Body Awareness Scale" and "Emotional Regulation Scale", and statistical tests were performed by single-factor covariate analysis (ANOVA) to evaluate the effectiveness of experimental processing. The study found the following: 1. College students participating in the study of Chinese classical dance therapy groups are generally satisfied with or agree with the content of the Chinese classical dance therapy group scheme designed in this study. 2. The Chinese classical dance therapy group can enhance the daily life awareness of college students. 3. The Chinese classical dance therapy group can improve the overall physical awareness, physical use, muscle tension, and physical control of university students. 4. The Chinese classical dance therapy group can increase the awareness of college students that breathing can help relax the body. 5. The Chinese classical dance therapy group can improve the overall emotional regulation and emotional reflection of college students. 6. The Chinese classical dance therapy group can improve college students' emotion adjustment strategies and has a tracking effect on emotional awareness and emotional efficacy. The research results can provide references and suggestions for psychological counseling practitioners and future research.

Energy saving technologies in the heat supply systems of Uzbekistan

The paper attempted to show the possibilities of improving the energy efficiency and reliability of heat supply services, as well as the quality of heating and hot water supply, by proposing the transition of heat supply systems to closed consumer connection schemes. The authors analyzed the results of experimental studies of elevator inputs that are not able to provide the required parameters in the heating system in time and schemes for connecting hot water to heating networks that have serious drawbacks, on the “Sergeli” and “Yunus-Obod” districts in Tashkent. As the analysis showed, the elevator connection of heating systems and the classical scheme for connecting open hot water supply systems do not provide stable heating modes and guaranteed water supply to places of water parsing with a temperature in the range of 60-70 °C. It is clear that it is necessary to reconsider decisions on connecting subscribers to the heat networks, to choose the best options that will normalize the supply of heating to consumers. In this regard, in the republic, it is proposed to use closed systems: heating the coolant through the heat exchange device of the house`s heating point from the boiler room.

MOISTURE SUPPLY AND WEED INFESTATION OF SPRING BARLEY CROPS (HORDEUM VULGARE L.) DEPENDING ON THE BASIC TILLAGE SYSTEM

Spring barley (Hordeum vulgare L.) is one of the most common crops in the world of agriculture. Field research was conducted at the Poltava State Agricultural Experimental Station. M. I. Vavilov during 2021–2022. The research results show that the smallest number of weeds in crop crops (32.8 pcs./m2) was counted during tillage using Mini-till technology. When tillage, according to classical technology, there was an increase in the number of weeds by 2.4 pcs/m2 compared to the Mini-till system. The maximum abundance of weeds was observed on the No-till variant, which is 5.1 pcs/m2 more compared to Mini-till tillage. A similar level of weed infestation of crops was observed with shallow tillage (37.4 pcs./ m2). A decrease in the number of weeds was achieved on average during the growing season of spring barley by 7.1%, compared to No-till technology when tillage according to the classical scheme, which provided for plowing to a depth of 20-22 cm. Studies have revealed that the most negligible mass of raw weed plants in an air-dry state was formed with shallow primary tillage. Compared to other experiment variants, their mass was less, by 4.7–20.7 and 4.6–20.3 %, respectively. Studies have found that regardless of the technology of primary tillage, annual monocotyledonous and dicotyledonous species prevailed in the structure of biological groups of weeds. As for perennial weeds, there was an increase in their share by 2.9–3.8 times compared to other variants of the experiment, only with shallow tillage. It was found that the largest reserves of available moisture in a meter layer of soil both at the time of sowing and harvesting spring barley were formed on the variants of non-flange tillage, which were more extensive, respectively, by 5.7–13.3 and 4.1–4.7 mm, compared to the variant of the classic primary tillage.

Analysis and identification of network failures in the information network

This article shows that each information system has its own characteristics, which are determined by the scope of its application. The importance and responsibility of tasks solved using real-time systems have led to high requirements for the reliability of these systems, and the failure of the entire information system or its individual components can lead to negative consequences. Network failure recognition is based on the principle of determining the nature of network failures based on the product system. This principle is implemented through a dialogue procedure within the framework of the Bayesian approach, which allows you to accumulate information coming from various sources in order to confirm (not confirm) a certain hypothesis. A logical conclusion management strategy was developed, the control parameters of which are the current probability of the truth of the hypotheses, the limits of their change, and the weight of the signs associated with these hypotheses. Accounting for the current probability of hypotheses and the limits of their change allows in the process of conclusion, firstly, to focus attention on the most promising (probable) hypothesis, and secondly, to stop the conclusion after reaching the upper threshold, which will reduce the number of signs to be checked, and thus shorten the dialogue time yourself. In addition, having reached the lower threshold, the hypothesis is rejected as implausible and no longer participates in the conclusion process, which also leads to a reduction in recognition time. Accounting for the weights of signs in the process of logical inference allows you to first of all check those signs that maximize the probability of the plausibility of hypotheses. In general, the developed strategy, unlike the classical scheme, generates a purposeful process of testing the plausibility of hypotheses, which leads to a reduction in recognition time.

Questions of admixture crossing in semi-fine-wool sheep breeding in Kyrgyzstan

The paper deals with the use of admixture crossing in semi-fine-wool sheep breeding in Kyrgyzstan and its results. The purpose of the research was to develop and scientifically substantiate the methods of using the North Caucasian meat and wool breed during admixture crossing for further improvement of the Tian Shan sheep breed. Generally accepted zootechnical methods were used (the classical scheme of introductory crossing), wool qualities were determined on the OFDA device – 2000. The half-blooded (1/2SKTSH) and quarter-blooded (1/4SKTSH) North Caucasian Tian Shan young animals have better wool qualities without reducing the live weight of the crossbreeds. At the same time, the crossbreeds obtained from the back crossing with wool of 58-56 quality in the specific weight of the herd reached 85.5%, and with the most desirable degree of fineness of 56 quality – 63.3%. According to wool density (M+), the proportion of mixed bred young ewes reached 33.3%, which was 25.2% more than that of half-bloods. It was revealed that the inheritance of wool density trait as a result of crossing these breeds had a positive effect on wool productivity. The crossbred wool cut from them had the best marketable appearance. All this makes it possible to switch to the breeding of quarter-blooded North Caucasian Tian Shan animals “in itself” in the future.

On the Adaptive Tracking Problem of Time-Varying Systems using the Congelation for Variables Method

This paper discusses the use of the so-called congelation of variables method in the reference tracking problem for a class of nonlinear systems with matched, time-varying, parametric uncertainty. It is shown that the tracking problem using the proposed framework can be decomposed into a zero-regulation problem and a disturbance rejection problem. To reduce the size of the disturbance term, a dynamical system with known input is incorporated into the parameter update law to generate a time-varying nominal parameter. To reject the remaining disturbance term, a sign-like function is exploited, which achieves an adjustable tracking performance in an average sense, while guaranteeing boundedness of all trajectories of the closed-loop system. The theory is illustrated by solving a path-tracking problem and it is shown that the proposed control scheme outperforms the classical scheme in the presence of time-varying parameters.

АНАЛИЗ КИНЕМАТИЧЕСКОЙ СХЕМЫ ПОРШНЕВОГО W-ОБРАЗНОГО ДВИГАТЕЛЯ С ПРИЦЕПНЫМИ ШАТУНАМИ

This article presents the analysis and results of analytical, calculation, and design solutions for the development of piston engines for aircraft (tractors, automobiles, etc.). The authors propose an original design of a W-shaped engine with trailer connecting rods and made a comparative analysis of design features. The main feature of the W-shaped engine design is a significant reduction in length, and, consequently, the length of the crankshaft. As known, the manufacturing of internal combustion engine crankshafts is a long, complex, and expensive procedure requiring a number operations for its mechanical and heat treatment. An important aspect of crankshaft design is the calculation of mechanical tension, torsional vibrations, and the hydraulic performance evaluation of the main and connecting rod bearing, including engine balancing as a whole. At the end of the article the operating schemes of the engine section are presented (the section consists of four pistons, two main and two connecting rods bearing kinematically connected to one crankpin). The design differences from the classical schemes of crank-connecting mechanism (CCM) allow us to design the W-shaped engine in accordance with the technical requirements. For example, maximum power can be achieved by using variant “A”, with an increase in the power and heat stress of the parts of the cylinder-piston group (CPG), when the section is organized according to variants “B” or “C”, the loading of CCM parts is increased, but the loading of CPG parts is reduced. Considering that a W-shaped engine with trailed connecting rods has a same piston stroke in main and side cylinders and the workflow pattern in each cylinder is identical and is moved at the crankshaft rotation angle – which allows the engine to be designed according to variants above – the performance characteristics of such an engine are significantly expanded due to electronic control. The authors consider continuation of the work in the implementation of a full set of calculation studies taking into account the design features of the engine with a W-shaped design of CCM.

A fast inertial primal–dual algorithm to composite optimization models with application to image restoration problems

In this paper, we consider a fast inertial primal–dual algorithm (FIPD) for finding minimization problems of the sum of a smooth function with Lipschitzian gradient, a non-smooth proximable function, and linear composite functions. We not only prove the convergence of the proposed algorithm, but also prove that the new algorithm can achieve the worst-case o(1/k2) optimal convergence rate in terms of objective function value. This work brings together and notably extends several classical splitting schemes, like the primal–dual splitting method (PDS) proposed by Condat, the algorithm which is presented by Chambolle and Pock, as well as the recent modified fast iterative shrinkage-thresholding algorithm. The efficiency of the proposed method is demonstrated on image denoising and image deblurring. Numerical results show that our iterative algorithm (FIPD) performs better than the original one (PDS).

A multigrid solver for the coupled pressure-temperature equations in an all-Mach solver with VoF

We present a generalisation of the all-Mach solver of Fuster and Popinet (2018) [1] to account for heat diffusion between two different compressible phases. By solving a two-way coupled system of equations for pressure and temperature, the current code is shown to increase the robustness and accuracy of the solver with respect to classical explicit discretization schemes. Different test cases are proposed to validate the implementation of the thermal effects: an Epstein-Plesset like problem for temperature is shown to compare well with a spectral method solution. The code also reproduces free small amplitude oscillations of a spherical bubble where analytical solutions capturing the transition between isothermal and adiabatic regimes are available. We show results of a single sonoluminescent bubble (SBSL) in standing waves, where the result of the DNS is compared with that of other methods in the literature. Moreover, the Rayleigh collapse problem is studied in order to evaluate the importance of thermal effects on the peak pressures reached during the collapse of spherical bubbles. Finally, the collapse of a bubble near a rigid boundary is studied reporting the change of heat flux as a function of the stand-off distance.

Application of Network Technologies in Low-Budget Television Production

The article considers the classical scheme of the broadcast news studio and the principle of operation of the television broadcasting system on the example of the standard of the international digital television system, which is the reference model of terrestrial digital television transmission. The structural scheme of the broadcast news studio is given, the functions of each block of the studio and the principle of their work are described. The diagram of the digital television system shows how the signal from the studio passes through the stages of encoding and modulation to the broadcasting antenna, and then the demodulated and decoded TV signal appears in the digital television application on the viewer's side. The interactive communication channel is also discussed in more detail. The diagram of the interactive communication channel presented in this article shows how the communication between the broadcasting company and the viewer of digital television takes place. However, given the current tendency of TV channels to move from broadcasting on digital television to online broadcasting on streaming platforms, the article considers an example of organizing an online broadcast on the YouTube platform. Using the example of equipment from the classical scheme of the broadcast studio, the selection of similar low-budget equipment for organizing a studio for online broadcasts was carried out. The list of low-budget equipment includes a video mixer, video cameras, lighting equipment and two types of microphones. The advantages and disadvantages of low-budget equipment are indicated, from which it can be concluded that low-budget equipment is not of poor quality, but is designed for a smaller number of connected equipment, so it is suitable for use in small television studios. The functions and possibilities of using the selected Blackmagic ATEM Mini Pro video mixer are considered. A scheme for organizing a live broadcast on the YouTube streaming platform using the selected equipment is presented. The low budget of the studio is substantiated by estimates and comparison with the budget of a similar educational television studio. The possibilities of remote access organizing to the workplace via VPN (Virtual Private Network) and RDC (Remote Desktop Connection) are also considered. These features allow employees to work from a remote location, not directly in the studio. The purpose of the article was to determine how does remote access delay the work of the studio and complicate the process of launching online broadcasts. Measurements of connection delay and broadcasting were carried out. According to the results of the measurements, it was concluded that both VPN and RDC insignificantly affects the connection speed of the equipment, so remote work can be equally comfortable as working directly in the studio. The difference between remote work and direct work in the studio consists of in the preliminary configuration of devices for remote connection and also remote work depends on the Internet connection entirely and light availability in the studio.

Locally order-preserving mapping for WENO methods

In our previous studies (Li and Zhong, 2021a; Li and Zhong, 2021b), the commonly reported issue that most of the existing mapped WENO schemes suffer from either losing high resolutions or generating spurious oscillations in long-run simulations of hyperbolic problems has been successfully addressed, by devising the improved mapped WENO schemes, namely MOP-WENO-X, where “X” stands for the version of the existing mapped WENO scheme. However, all the MOP-WENO-X schemes bring about the serious deficiency that their resolutions in the region with smoothly varying high-frequency waves are dramatically decreased compared to their associated WENO-X schemes. The purpose of this paper is to overcome this drawback. We first present the locally order-preserving (LOP) mapping. Then, by using a new proposed posteriori adaptive technique, we apply this LOP property to obtain the new mappings from those of the WENO-X schemes. The essential idea of the posteriori adaptive technique is to identify the global stencil in which the existing mappings fail to preserve the LOP property, and then replace the mapped weights with the weights of the classic WENO-JS scheme to recover the LOP property. We build the resultant mapped WENO schemes and denote them as LOP-WENO-X. The numerical experiments demonstrate that the resolutions in the region with high-frequency but smooth waves of the LOP-WENO-X schemes are similar to or even better than those of their associated WENO-X schemes and naturally much higher than the MOP-WENO-X schemes. Furthermore, the LOP-WENO-X schemes gain all the great advantages of the MOP-WENO-X schemes, such as attaining high resolutions and in the meantime preventing spurious oscillations near discontinuities when solving the one-dimensional linear advection problems with long output times, and significantly reducing the post-shock oscillations in the simulations of the two-dimensional problems with shock waves.

Multi-proxy Signature Scheme Using Five-qubit Entangled State Based on Controlled Quantum Teleportation

With the upgrading of communication technology and the rapid development of quantum computing, the classical digital signature schemes are faced with unprecedented challenges, so the research on quantum digital signature is imperative. In this paper, we propose a multi-proxy signature scheme based on controlled quantum teleportation of five-qubit entangled state. In this scheme, quantum fourier transform is used as an encryption method to encrypt message, which improves the quantum efficiency compared with the quantum one-time pad. The five-qubit maximally entangled state which is qubit threshold quantum error correction required is used as the quantum channel to ensure the stability of the scheme. Security analysis shows that our scheme is unforgeable and undeniable, and it can resist the intercept-resend attack.

Anisotropy of the friction forces of rest and sliding frictionof single crystals of ice

The properties of the ice of natural reservoirs are due to its crystalline structure. The dependence of the mechanical and strength characteristics of single ice crystals on the angle between the direction of application of force to a single crystal and the direction of its C-axis is known. Basically, this dependence is due to the possibility of the base plates of a single crystal of ice sliding relative to each other. In physics, in addition to the mechanical and strength characteristics of a solid, the properties of the surfaces of a solid state, manifested in the process of friction, are of great importance. The friction of two single crystals of ice relative to each other has been investigated in experiments on rest friction and sliding friction. From an artificially grown plate of a single ice crystal, samples of single crystals of ice with a certain orientation of the C-axis were made for the experiment. The measurement of the rest friction coefficient of a single ice crystal was realized according to the classical scheme of recording the minimum angle at which the single crystal began to roll down an inclined surface. The dependence of the rest friction coefficient of ice single crystals on the mutual orientation of the C-axes of single crystals relative to each other was discovered. The coefficients of rest friction in the case that the C-axes of single ice crystals are parallel to each other significantly exceed those obtained when the C-axes of single ice crystals are perpendicular to each other. Measurements have shown that the anisotropy of sliding friction increases with increasing initial velocity of the single crystal on the surface of the second single crystal. This is explained by the fact that with the growth of the path traveled by the M2 crystal, the time of interaction of single crystals of ice also increases, during which the properties of the anisotropy of single crystals of ice relative to sliding friction are manifested. Studies have shown the presence of anisotropy of the friction forces of rest and friction of sliding of a pair of single crystals of ice.

Preoperative Radio(Chemo)Therapy in Breast Cancer: Time to Switch the Perspective?

Radiation therapy represents, together with surgery and systemic treatment, the triad on which the current management of patients with breast cancer is based, achieving high control and survival rates. In recent years we have witnessed a (r)evolution in the conception of breast cancer treatment. The classic scheme of surgery followed by systemic treatment and radiotherapy is being subverted and it is becoming more and more frequent to propose the primary administration of systemic treatment before surgery, seeking to maximize its effect and favoring not only the performance of more conservative surgeries but also, in selected cases, increasing the rates of disease-free survival and overall survival. Radiotherapy is also evolving toward a change in perspective: considering preoperative primary administration of radiotherapy may be useful in selected groups. Advances in radiobiological knowledge, together with technological improvements that are constantly being incorporated into clinical practice, support the administration of increasingly reliable, precise, and effective radiotherapy, as well as its safe combination with antitumor drugs or immunotherapy in the primary preoperative context. In this paper, we present a narrative review of the usefulness of preoperative radiotherapy for breast cancer patients and the possibilities for its combination with other therapies.

New compact difference schemes on non‐uniform collocated and staggered grids for convection‐dominated flows

SummaryThis paper deals with the formulation of the tridiagonal compact difference schemes for derivatives up to second‐order with boundary stencils on non‐uniform grids. A compact scheme for the first derivative with interpolation is also devised on staggered non‐uniform grids. The developed schemes with non‐uniform spacing transform to respective classical compact schemes for the case of uniform mesh spacing. The resolution, numerical diffusion, and anti‐diffusion features of the devised schemes are evaluated using global spectral analysis. Applications to the direct numerical simulation (DNS) of two‐dimensional lid‐driven cavity (LDC) flow governed by Navier‐Stokes equations and wave‐propagation following linear rotating shallow water (LRSWE) equations with variable grid‐spacing are discussed at different choices of parameters. Computed results are also compared with solutions available in the literature.