Abstract
A new numerical approach is proposed for fast and efficient calculation of electric waves passing through wave microdevices using the Helmholtz equation. The efficiency, speed, and accuracy of the method are investigated.
A new numerical approach is proposed for fast and efficient calculation of electric waves passing through wave microdevices using the Helmholtz equation. The efficiency, speed, and accuracy of the method are investigated.
A group of high-energy positive O+ ions in a plasma flow from a high-current pulsed magnetron discharge with a hot target in an Ar/O2 gas mixture. The mechanism of occurrence of accelerated O+ ions is the conversion of negative ions accelerated in the cathode layer O– → O+ in the processes of charge exchange or ionization by electron impact.
The article analyses the effectiveness of a chaotic communication scheme based on synchronization of hyperbolic chaos generators used as a receiver and a transmitter. It is shown that useful information nonlinearly mixed into the transmitter signal can be detected by the receiver if the receiver has stable synchronization with the transmitted signal. Research, aimed to confirm the hypothesis that robustness, strong chaoticity and noise-like wideband spectrum of this type of oscillators provide reliability and stability of transmission, has been carried out. This study also shows the effect of noise and frequency distortion of the signal in a communication channel on the quality of information detection.
This article presents a bidirectional optical fiber communication system employing Dual Polarization-64 Quadrature Amplitude Modulation and Digital Signal Processing (DP-64QAM and DSP). With sixteen channels operating at 120 Gb/s each, the system achieves a total capacity of 1920 Gbps. OptiSystem V.19 software simulations confirm compliance with ITU-T 5G fronthaul requirements in G-series Recommendations-Supplement 66. Performance evaluation focuses on Bit Error Rate (BER), incorporating an Optical Signal-to-Noise Ratio (OSNR) and an adaptable optical span. Simulation results establish the system’s suitability as an F1 and Fx 5G fronthaul link for functional splits of 1 to 7c, aligning with ITU-T stipulations (<120 Gbps per channel). The design employs a bidirectional single-mode optical fiber for up to 13 km and 13.5 km distances in downlinks and uplinks. Incorporating two Dispersion Compensator Filters (DCFs) extends this to 19.5 km. This enhancement underscores the adaptability for real-world applications, particularly in extended-range scenarios necessitating robust and high-capacity communication links.
Traffic Classification (TC) is a key part of many network frameworks that provide Quality of Service (QoS) for traffic. Encrypted TC algorithms often use the Server Name Indication (SNI) field, which indicates the domain name of the server to which the client establishes a connection, and which is a clear marker of the traffic category. However, the new Encrypted ClientHello (ECH) extension, which supplements the TLS 1.3 protocol significantly complicates TC because most of the messages of the TLS handshake become encrypted, including SNI. With ECH, the accuracy of TC algorithms that use open TLS parameters significantly degrades. This paper studies the indistinguishability of the encrypted traffic considering the remaining open TLS parameters.
Abstract—Point cloud registration is a central problem in many computer vision problems. However, ensuring global consistency of the results of pairwise registration of point clouds is still a challenge when there are multiple clouds because different scans should be converted to a common coordinate system. This paper describes a global refinement algorithm that first estimates rotations and then estimates parallel translations. For global refinement of rotations, a closed-form algorithm based on matrices is used. For global refinement of parallel translations, a closed-form algorithm is also used. The proposed algorithm is compared with other global refinement algorithms.
Particle Image Velocimetry (PIV) is used to study the nonstationary flow pattern around a drop of a dielectric liquid of dibutyl phthalate surrounding water of weak conductivity under the action of a microsecond current pulse. It has been found that the time of existence of the induced vortex flow in water significantly exceeds the duration of the current pulse. During the action of the pulse, only small perturbations develop on the surface of the drop, while the final perturbations of the surface develop at much longer times, exceeding the duration of the current pulse by two or more orders of magnitude, and are associated with the evolution of the water flow around the drop. It is shown that the value of the maximum velocity in the induced water flow is affected by the potential of the needle at a constant duration and amplitude of the current.
Mechanisms of reversible and irreversible failures that occur in microwave semiconductor devices, microcircuits, and microprocessors under the impact of powerful electromagnetic pulses, either single or periodic, are analyzed. It is shown that, in microprocessors, failures of both types are generated by the electrothermal instabilities, being developed within negligibly small volumes of a device. The dependences of the threshold energy of failures on the pulse amplitude, duration, and repetition rate are explained. The results of the calculation are consistent with the experimental data.
This study is devoted to the study of metal–insulator–semiconductor (MIS) structures based on n-HgCdTe (MCT) grown by molecular beam epitaxy (MBE) in the NBνN configuration, intended for the development of infrared (IR) detectors with reduced dark currents for MWIR and LWIR spectral ranges. Seven types of MIS structures have been studied by the admittance spectroscopy method. It is shown that the measurements of the frequency dependences of the impedance of MIS devices make it possible to accurately determine the differential resistance of the barrier structure. It has been established that for one of the studied structures, the values of the differential resistance are determined by the bulk component of the dark current, while the surface leakage component does not significantly affect the measured impedance. It is shown that if the problem of passivation of mesa structures is solved, it is possible to fabricate efficient MWIR and LWIR nBn, NBνN detectors based on MBE HgCdTe with high threshold parameters.
The problem of arbitrary propagation of electromagnetic waves in a tangentially magnetized one-side metallized bigyrotropic layer is solved without using the magnetostatic approximation. It is shown that, in this problem, Maxwell’s equations are reduced to a differential equation corresponding to a biquadratic characteristic equation with four roots kx21, ‒kx21, kx22, and –kx22 describing the distribution of the wave in the layer cross section. A dispersion equation for describing waves with real kx21 and kx22 values is obtained. Using this equation, the characteristics of spin waves in a one-side metallized ferrite plate (a special case of a bigyrotropic layer) are calculated for the frequencies above the ferromagnetic resonance frequency. It is found for these waves that quantity kx21 can take both real and imaginary values, while quantity kx22, only real ones. It is found that, at a certain frequency, the spin wave has an isofrequency curve almost identical to a straight line.
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