Symmetric Scheme Research Articles

Identifying possible ways for adapting an open wagon for transporting containers

The object of this study is the processes of perception and redistribution of loads in the supporting structure of a open wagon loaded with containers, taking into account the new scheme of their fastening. For safe transportation of containers in an open wagon, it is suggested to use a removable module. This module works according to the principle of an intermediate adapter between the container and the open wagon body. Fastening of the module itself in the open wagon is carried out through the fitting stops, which are placed on the floor of the open wagon. Mathematical modeling was carried out to determine the longitudinal dynamic load acting on the container fixed according to the new scheme in the open wagon. To this end, a mathematical model was built that characterizes the longitudinal movements of the "open wagon - removable module - container" system. Determination of the accelerations that act on the supporting structure of the open wagon loaded with containers was also carried out by means of computer simulation. Verification of the formed model of the dynamic load of the open wagon was carried out according to the F-criterion. Also, as part of the study, a modal analysis of the load-bearing structure of a open wagon loaded with containers was carried out, which made it possible to assess its traffic safety. A feature of the results obtained as part of the research is that the proposed design of the removable module could be used not only for fastening containers but also for transportation of other types of cargo. The field of practical application of the results is railroad transport, including other transportation industries. The conditions for the practical use of the results are a symmetrical scheme of loading the body of a open wagon with containers. The results of this study will contribute to increasing the efficiency of container transportation and the profitability of railroad transport

Secured Fog-Body-Torrent : A Hybrid Symmetric Cryptography with Multi-layer Feed Forward Networks Tuned Chaotic Maps for Physiological Data Transmission in Fog-BAN Environment

Recently, the Wireless Body Area Networks (WBAN) have become a promising and practical option in the tele-care medicine information system that aids for the better clinical monitoring and diagnosis. The trend of using Internet of Things (IoT) has propelled the WBAN technology to new dimension in terms of its network characteristics and efficient data transmission. However, these networks demand the strong authentication protocol to enhance the confidentiality, integrity, recoverability and dependability against the emerging cyber-physical attacks owing to the exposure of the IoT ecosystem and the confidentiality of biometric data. Hence this study proposes the Fog based WBAN infrastructure which incorporates the hybrid symmetric cryptography schemes with the chaotic maps and feed forward networks to achieve the physiological data info security without consuming the characteristics of power hungry WBAN devices. In the proposed model, scroll chaotic maps are iterated to produce the high dynamic keys streams for the real time applications and feed-forward layers are leveraged to align the complex input-output associations of cipher data for subsequent mathematical tasks. The feed forward layers are constructed which relies on the principle of Adaptive Extreme Learning Machines (AELM) thereby increasing randomness in the cipher keys thereby increasing its defensive nature against the different cyber-physical attacks and ensuring the high secured encrypted-decrypted data communication between the users and fog nodes. The real time analysis is conducted during live scenarios. BAN-IoT test beds interfaced with the heterogeneous healthcare sensors and various security metrics are analysed and compared with the various residing cryptographic algorithms. Results demonstrates that the recommended methodology has exhibited the high randomness characteristics and low computational overhead compared with the other traditional BAN oriented cryptography protocol schemes

Influence of electron cyclotron current drive on the pressure crashes caused by the 2/1 double tearing modes

Abstract A module with self-consistent evolution of driven current is developed and coupled with the resistive-MHD equations in the three-dimensional, toroidal, and nonlinear simulation code (CLT). The driven current equation is solved with a second-order accuracy symmetric scheme, which exhibits good conservation properties. With the new module, we find that the driven current can self-consistently concentrate inside the magnetic island when the parallel diffusion of the driven current is sufficiently large. The efficiency of the driven current on tearing mode suppression will then be much higher than those with stationary distributions. With the new module, the influence of electron cyclotron current drive (ECCD) on the nonlinear evolution of the 2/1 double tearing modes (DTMs) is investigated. When co-ECCD deposits on the outer resonant surface, the local magnetic shear is reduced, and the growth rates of the DTMs decrease; if ctr-ECCD deposits on the outer resonant surface, the local magnetic shear increases, and the DTMs become more unstable. However, things will be different if ECCD deposits on the inner resonant surface since the local magnetic shear is negative. The co-ECCD deposited on the inner resonant surface increases the negative shear and then promotes the growth of the DTMs; while the ctr-ECCD suppresses the DTMs. It is also found that the off-axis and central pressure crashes associated with the 2/1 DTMs can be converted to each other by properly depositing the driven current. To convert a central crash to an off-axis crash, the co-ECCD should be deposited on the outer resonant surface, or the ctr-ECCD deposited on the inner resonant surface. While, the co-ECCD should be deposited on the inner rational surface, or the ctr-ECCD deposited on the outer rational surface to convert an off-axis crash to a central crash. The co- or ctr-ECCD should be larger than a threshold for such transitions, and the threshold value is mainly determined by the location of the inner resonant surface.

Effect of parity–time symmetry operation on entanglement distribution in two parallel Heisenberg spin chains

Abstract The effect of the parity–time ( PT ) symmetry operation on the entanglement transfer in two parallel Heisenberg spin chains is investigated. We give two schemes, i.e. pre- and post- PT symmetric operations, to demonstrate the performance of the PT symmetric operation on the entanglement dynamics of two qubits. In our investigation, we find that the effect of pre- PT symmetric operation schemes on the protection of entanglement of two qubits in the case of double spin chains is superior to that of the single spin chain case. Conversely, the effect of the post- PT symmetric operation scheme on the protection of entanglement of two qubits in the single spin chain case is better than that in the double spin chain case.

Symmetric Cyclic Quantum Teleportation using Channel Parameter Matrix

Abstract The Channel Parameter Matrix (CPM) is a matrix containing general variables used to formulate the channel used for transmitting quantum bit (qubit) in quantum teleportation. CPM is an important parameter to describe the whole process in quantum teleportation. The scheme used in this process is symmetric cyclic. In cyclic scheme, there is three parties: Alice, Bob, and Charlie. For symmetric cyclic scheme, Alice sends one qubit to Bob, Bob sends one qubit to Charlie, Charlie sends one qubit to Alice. Then the size of CPM for symmetric is 8 x 8. Further derivation show that CPM depend on normalization constant, unitary matrix, and type of measurement.

Efficient provable dual receiver hybrid and light weight public key schemes based on the discrete logarithm problem without pairings

AbstractDual‐receiver proxy re‐encryption is a cryptographic technique that enables secure data sharing among multiple authorized users or entities. It has gained significant attention for its ability to manage access permissions, data confidentiality, and streamline communication channels. These schemes have been widely used in various applications, including healthcare systems, cloud computing, Internet of Things (IoT) systems, collaborative environments, and secure communication channels. This paper aims to propose two proxy re‐encryption schemes for dual receivers without pairings. The first is dual receiver lightweight proxy re‐encryption without pairings (DR‐LWPRE‐WP), which uses a public key scheme to reduce computational complexity. The second is dual receiver hybrid proxy re‐encryption without pairings (DR‐HPRE‐WP), which incorporates public key and symmetric key schemes. Both schemes offer protection against selected plaintext attacks based on the decisional Diffie‐Hellman principle. The DR‐LWPRE‐WP scheme reduces computation by approximately 53% compared to pairing‐based schemes, making it suitable for lightweight applications like the Internet of Things. The computational efficacy of these schemes offers significant benefits for resource‐constrained environments and practical implementations.

Analytical solutions for the advective–diffusive ice column in the presence of strain heating

Abstract. A thorough understanding of ice thermodynamics is essential for an accurate description of glaciers, ice sheets and ice shelves. Yet there exists a significant gap in our theoretical knowledge of the time-dependent behaviour of ice temperatures due to the inevitable compromise between mathematical tractability and the accurate description of physical phenomena. In order to bridge this shortfall, we have analytically solved the 1D time-dependent advective–diffusive heat problem including additional terms due to strain heating and depth-integrated horizontal advection. Newton's law of cooling is applied as a Robin-type top boundary condition to consider potential non-equilibrium temperature states across the ice–air interface. The solution is expressed in terms of confluent hypergeometric functions following a separation of variables approach. Non-dimensionalization reduces the parameter space to four numbers that fully determine the shape of the solution at equilibrium: surface insulation, effective geothermal heat flow, the Péclet number and the Brinkman number. The initial temperature distribution exponentially converges to the stationary solution. Transient decay timescales are only dependent on the Péclet number and the surface insulation, so higher advection rates and lower insulating values imply shorter equilibration timescales, respectively. In contrast, equilibrium temperature profiles are mostly independent of the surface insulation parameter. We have extended our study to a broader range of vertical velocities by using a general power-law dependence on depth, unlike prior studies limited to linear and quadratic velocity profiles. Lastly, we present a suite of benchmark experiments to test numerical solvers. Four experiments of gradually increasing complexity capture the main physical processes for heat propagation. Analytical solutions are then compared to their numerical counterparts upon discretization over unevenly spaced coordinate systems. We find that a symmetric scheme for the advective term and a three-point asymmetric scheme for the basal boundary condition best match our analytical solutions. A further convergence study shows that n≥15 vertical points are sufficient to accurately reproduce the temperature profile. The solutions presented herein are general and fully applicable to any problem with an equivalent set of boundary conditions and any given initial temperature distribution.

Efficient high-order operator-splitting schemes for solving the time-dependent Schrödinger equation

Several fourth-order symmetric operator-splitting schemes with four and five stages for solving the time-dependent Schrödinger equation have been proposed. These schemes have been studied and compared with some optimal fourth- and sixth-order operator split schemes reported in the literature using a one-dimensional model and several realistic three-dimensional triatomic reactive scattering problems in Jacobi coordinates. Two new fourth-order operator-splitting schemes with four and five stages, which are more efficient than previously reported schemes, are recommended for the realistic numerical solution of the time-dependent Schrödinger equation in the field of molecular dynamics. It was found that the order-preserving method proposed by McLachlan works well for three-dimensional triatomic reactive scattering problems in Jacobi coordinates, despite the complicated form of the Hamiltonian.

Determining patterns of the vertical load on a covered wagon roof with a frame in the form of a triangular arch

The object of this paper is the processes of perception and redistribution of loads in the roof of a railroad covered wagon with a frame in the form of a triangular arch. To reduce the tare of the covered wagon, it is proposed to improve the structure of its roof. A feature of this improvement is that the roof frame is made in the form of a triangular arch with a reinforcing belt. This contributes to the reduction of the total mass of the roof compared to a typical structure. The selection of execution profiles of the beams forming the arch is carried out according to the maximum values of the moments that act in their cross-section. Taking into account the chosen profile of the arches, the calculation of the strength of the roof when it receives vertical loads was carried out. It was established that the strength of the roof under the considered load schemes is within the permissible stress values. Since the improvement of the roof structure contributes to the reduction of its weight by 1.8 % compared to the prototype, the movement of the covered wagon was evaluated under conditions of moving while empty. To this end, a mathematical modeling of the load of the covered wagon in the vertical plane during its movement along the joint unevenness was carried out. On the basis of the performed calculation, it was established that the movement of the wagon is assessed as "good". Special feature of the results is that the reduction of the tare of the supporting structure of the wagon was achieved by improving its roof, as the least loaded unit. The field of practical application of the results is railroad transport, including other areas of mechanical engineering. The conditions for the practical use of the results are a symmetrical roof load scheme in operation. The results of this research could contribute to advancements related to the design of modern structures of freight wagons with improved technical and economic indicators

Robust discontinuous Galerkin-based scheme for the fully-coupled nonlinear thermo-hydro-mechanical problem

Abstract We present and analyze a discontinuous Galerkin method for the numerical modeling of the nonlinear fully-coupled thermo-hydro-mechanic problem. We propose an arbitrary-order weighted symmetric interior penalty scheme that supports general polytopal grids and is robust with respect to strong heterogeneities in the model coefficients. We focus on the treatment of the nonlinear convective transport term in the energy conservation equation and we propose suitable stabilization techniques that make the scheme robust for advection-dominated regimes. The stability analysis of the problem and the convergence of the fixed-point linearization strategy are addressed theoretically under mild requirements on the problem data. A complete set of numerical simulations is presented in order to assess the convergence and robustness properties of the proposed method.

Protection of entanglement in two independently decohering qubits via local prior and post parity-time symmetry operations

Protection of entanglement of two qubits undergoing two independent amplitude damping channels using a local parity-time ( PT ) symmetric operation is exactly studied. First, the explicit expressions of concurrence quantifying the entanglement of two qubits with both local PT symmetric operation and two amplitude damping channels are obtained. Then, we give two schemes, i.e. prior and post PT symmetric operations, to show the performance of PT symmetric operation on entanglement dynamics of two qubits. By investigation, we find that the effect of prior PT symmetric operation schemes on the protection of entanglement of two qubits in the double channel case is superior to that of the single channel case. Conversely, the effect of post PT symmetric operation scheme on the protection of entanglement of two qubits in the single channel case is better than that in the double channel case. In other words, the local PT symmetric operation approach may have potential applications in combating amplitude damping decoherence.

New Order 2.0 Simplified Weak Itô–Taylor Symmetrical Scheme for Stochastic Delay Differential Equations

In this article, we construct a new order 2.0 simplified weak Itô–Taylor symmetrical scheme for stochastic delay differential equations. By the new local weak convergence lemma and the connection inequality, we theoretically prove the global weak convergence theorem in two parts on the basis of Malliavin stochastic analysis. Meanwhile, numerical examples are presented to illustrate the error and convergence results. Furthermore, the obtained results display the influence of the delay coefficient on global errors.

A high-order upwind compact difference scheme for solving the streamfunction-velocity formulation of the unsteady incompressible Navier–Stokes equations

In this paper, we propose an upwind compact difference method with fourth-order spatial accuracy and second-order temporal accuracy for solving the streamfunction-velocity formulation of the two-dimensional unsteady incompressible Navier–Stokes equations. The streamfunction and its first-order partial derivatives (velocities) are treated as unknown variables. Three types of compact difference schemes are employed to discretize the first-order partial derivatives of the streamfunction. Specifically, these schemes include the fourth-order symmetric scheme, the fifth-order upwind scheme, and the sixth-order symmetric scheme derived by combining the two parts of the fifth-order upwind scheme. As a result, the fourth-order spatial discretization schemes are established for the Laplacian term, the biharmonic term, and the nonlinear convective term, along with the Crank–Nicolson scheme for the temporal discretization. The unconditional stability characteristic of the scheme for the linear model is proved by discrete von Neumann analysis. Moreover, six numerical experiments involving three test problems with the analytic solutions, and three flow problems including doubly periodic double shear layer, lid-driven cavity flow, and dipole-wall interaction are carried out to demonstrate the accuracy, robustness, and efficiency of the present method. The results indicate that the present method not only has good numerical performance but also exhibits quite efficiency.

Infrared Small Target Detection Based on Density Peak Search and Local Features

The detection of small infrared targets is still a challenging task and efficient and accurate detection plays a key role in modern infrared search and tracking military applications. However, small infrared targets are difficult to detect due to their weak brightness, small size and lack of shape, structure, texture, and other information elements. In this paper, we propose a target detection method. First, to address the problem that the proximity of targets to high-brightness clutter leads to missed detection of candidate targets, a Gaussian differential filtering preprocessed image is used to suppress high-brightness clutter. Second, a density-peaked global search method is used to determine the location of candidate targets in the preprocessed image. We then use local contrast to the candidate target points to enhance the gradient features and suppress background clutter. The Facet model is used to compute multidirectional gradient features at each point. A new efficient surrounding symmetric region partitioning scheme is constructed to capture the gradient characteristics of targets of different sizes in eight directions, followed by weighting the candidate target gradient characteristics using the standard deviation of the symmetric region difference. Finally, an adaptive threshold segmentation method is used to extract small targets. Experimental results show that the method proposed in this paper has better detection accuracy and robustness compared with other detection methods.

Hybrid cryptography-based scheme with conditional privacy-preserving authentication and memory-based DOS resilience in V2X

To secure Vehicle-to-everything (V2X) communications, many Conditional Privacy-Preserving Authentication schemes (CPPA) use symmetric and asymmetric encryption during the authentication process. However, several existing schemes have some security limitations regarding VANET requirements. In many symmetric cryptography-based schemes, the participants are required to share the same keys which could compromise the security of the network in case the key of one participant is compromised, while many asymmetric cryptography-based schemes take much time during the authentication process, and don't address the denial-of-service attack. In this paper, we propose a certificateless scheme that does not require a certificate and prevents the escrow problem. Plus, it uses the elliptic curve cryptography and avoids bilinear pairing and Map-to-Hash functions. We call our scheme Hybrid Cryptography-Based Scheme with a Conditional Privacy-Preserving Authentication (HCBS-CPPA), as it uses both symmetric and asymmetric cryptography during the authentication process. Our scheme combines the strength of an asymmetric encryption that satisfies non-repudiation, and the strength of a symmetric encryption that allows to perform a lightweight authentication. In addition, we show that our scheme is resilient to memory-based Denial of Service (DOS) attack which occurs when an attacker floods the memory of a receiver with invalid messages. A security proof shows that HCBS-CPPA is secure in the random oracle. Regarding the simulation of our scheme, it turns out that HCBS-CPPA has the best performance when compared with several existing certificateless schemes. Additionally, it requires less execution time during the signing and verification process, as well as less communication overhead when compared to the existing schemes.

Research on electrical capacitance tomography (ECT) detection of cerebral hemorrhage based on symmetrical cancellation method

Currently, there is an urgent need for a fast and portable intracerebral hemorrhage (ICH) detection technology for pre-hospital emergency scenarios. Owing to the disproportionately elevated permittivity of blood compared to other brain tissues, Electrical Capacitance Tomography (ECT) offers a viable modality for mapping the spatial distribution of permittivity within the brain, thus facilitating the imaging-based identification of ICH. Currently, ECT is confined to time-differential imaging due to limited sensitivity, and this methodology requires non-hemorrhagic measurements for comparison, data that are frequently inaccessible in clinical contexts. To overcome this limitation, in accordance with the natural bilateral symmetry of the cerebral hemispheres, a symmetrical cancellation scheme is introduced. In this method, electrodes are uniformly arrayed around the cranial periphery and strategically positioned in a symmetrical manner relative to the sagittal suture. Subsequently, the measured capacitances for each electrode pair are subtracted from those of their symmetrical counterparts aligned with the sagittal suture. As a result, this process isolates the capacitance attributable solely to hemorrhagic events within a given hemisphere, permitting the absolute imaging of ICH. To assess the feasibility of this method, simulation and empirical imaging were conducted respectively on a numerical hemorrhage model and three physical models (a water-wrapped hemorrhage model, an isolated porcine fat-wrapped hemorrhage model, and an isolated porcine brain tissue-wrapped hemorrhage model). Traditional absolute imaging, time-differential imaging and symmetrical cancellation imaging were performed on all models. The results substantiate that the proposed imaging modality is capable of obtaining absolute imaging of ICH. But a mirrored artifact, symmetrical to the site of the actual hemorrhage image appeared in each of the imaging results. This mirror artifact was characterized by identical dimensions and an inverted pixel-value schema, an intrinsic consequence of the symmetrical cancellation imaging algorithm. The real image of hemorrhage can be ascertained through pre-judgment with the symptoms of the patient. Additionally, the quality of this imaging is seriously dependent on the precise alignment between the electrodes and the sagittal suture of the brain; even a minor deviation in symmetry could introduce excessive noises. Thus, the complicated operational procedures remain as challenges for practical application.

Minimization of dispersion and non-linear effects in WDM based long-haul high capacity optical communication systems

Abstract Chromatic dispersion and nonlinear impairments pose challenges in high-capacity optical transmission systems, leading to signal distortions, channel interference and diminished the transmission performances. This paper explores the utilization of dispersion compensating fibers (DCF) using different schemes to mitigate the dispersion that accumulates along the length of a fiber in a 16 × 10 Gbps high-capacity long haul WDM system over a range of 500 km. When different wavelengths of light pulses are transmitted through an optical fiber, they experience varying speeds due to the refractive index’s wavelength dependency. As a result, the light pulses become temporally spread out as they travel through the fiber, and this dispersion persists throughout the fiber’s length. Considering non-linear effects such as self-phase modulation (SPM) and cross-phase modulation (XPM), this paper analyze and compare the three compensation schemes of DCF in a 16 channel WDM system. Moreover the impact of non-linearities based on fiber length are also analyzed and compared. The results are evaluated by comparing metrics such as Q-factor, bit error rate (BER) and eye height. The analysis concludes that the symmetrical compensation scheme of DCF outperforms the pre- and post-compensation scheme. This finding suggests that the symmetrical compensation method offers a promising solution for high-capacity access networks, providing high spectral efficiency, cost-effectiveness, and improved flexibility.

Enhancing block cipher security with key-dependent random XOR tables generated via hadamard matrices and Sudoku game

The XOR operator is a simple yet crucial computation in computer science, especially in cryptography. In symmetric cryptographic schemes, particularly in block ciphers, the AddRoundKey transformation is commonly used to XOR an internal state with a round key. One method to enhance the security of block ciphers is to diversify this transformation. In this paper, we propose some straightforward yet highly effective techniques for generating t-bit random XOR tables. One approach is based on the Hadamard matrix, while another draws inspiration from the popular intellectual game Sudoku. Additionally, we introduce algorithms to animate the XOR transformation for generalized block ciphers. Specifically, we apply our findings to the AES encryption standard to present the key-dependent AES algorithm. Furthermore, we conduct a security analysis and assess the randomness of the proposed key-dependent AES algorithm using NIST SP 800-22, Shannon entropy based on the ENT tool, and min-entropy based on NIST SP 800-90B. Thanks to the key-dependent random XOR tables, the key-dependent AES algorithm have become much more secure than AES, and they also achieve better results in some statistical standards than AES.

ПАРАМЕТРИЧНЕ МОДЕЛЮВАННЯ НАПРУЖЕНО-ДЕФОРМОВАНОГО СТАНУ НЕСУЧОЇ КОНСТРУКЦІЇ ПРИЧІПНОГО ШИРОКОЗАХВАТНОГО ПОСІВНОГО КОМПЛЕКСУ ПРИ НАВАНТАЖЕННІ В РЕЖИМІ СІВБИ

On the basis of a parametric finite element model of the supporting structure of a trailed wide-grip sowing complex ATD 18.35, taking into account the mechanical properties of materials of metal structures, characteristics of dynamic effects in the sowing mode, the most dangerous combinations of loads for individual elements of the supporting structure are determined, recommendations for rational design are suggested. The calculated symmetrical scheme of the supporting structure with more than 600 constituent elements was loaded, including a possible asymmetric load. Data on the loading of the spatial frame of the supporting structure were previously obtained as a result of a wide field experiment carried out in the field.

Fast nonlinear Fourier transform algorithms for optical data processing.

The nonlinear Fourier transform (NFT) is an approach that is similar to a conventional Fourier transform. In particular, NFT allows to analyze the structure of a signal governed by the nonlinear Schrödinger equation (NLSE). Recently, NFT applied to NLSE has attracted special attention in applications of fiber-optic communication. Improving the speed and accuracy of the NFT algorithms remains an urgent problem in optics. We present an approach that allows to find all variants of symmetric exponential splitting schemes suitable for the fast NFT (FNFT) algorithms with low complexity. One of the obtained schemes showed good numerical results in computing the continuous spectrum compared with other fast fourth-order NFT schemes.