Design of local heterogeneous system control networks of a new generation with the preservation of the optimality of the main topological functionals of the network

The paper discusses On-Board Computing Control Systems (OBCS) in astronautics, avionics, autonomous mobile devices, robotics, weapons control and multi-core microprocessors. This is sort of a “backbone”, which unites many sensors, calculators, control and executive devices. The architecture of these networks was developed some 30-40 years ago. At that time, these systems met the technical conditions in terms of dynamics and reliability. Nowadays, these systems must perform their functions for 10 to 15 years without maintenance. The performance of system networks must be high enough to solve such tasks as monitoring “swarms” that comprise hundreds of objects or work as a “garbage collectors” in space orbits. Nevertheless modern system networks continue to be based on bus or multi-bus architectures. Since these systems are serial for active nodes, a multi-bus solution is a main way to increase the performance of networks by using very high frequencies that amount to 2 ÷ 4 GHz. It’s an extensive path of development, which is problematic. More acceptable would be an intensive path of development, which, in electronics and computer engineering, is associated with the parallelism of task execution. It means that the operating frequencies may not be ultra-high, not exceeding that of modern devices for frequencies of 10 – 600 MHz. However, such devices should work in a parallel mode. The paper proposes a new approach to designing of heterogeneous parallel control system networks, solving parallel tasks, and a conflict-free management of “passive” nodes. To the best of our knowledge, such control system networks are not available as yet.

Endoscopic ultrasonography in the diagnosis of pathology of the gastrointestinal tract

Endoscopic ultrasonography is a relatively new endoscopic method of examination to determine the invasion of tumors of the gastrointestinal tract, detection and sizing of pancreatic tumors, diagnosis of chronic pancreatitis, pathology of the biliary tract. The method combines the possibilities of two studies: endoscopic and ultrasound. The study is performed using a video endoscope, at the end of which is a scanning ultrasound sensor. The advantages of endoscopic ultrasound over traditional ultrasound examination through the anterior abdominal wall are that the ultrasound sensor under visual control through the lumen of the digestive tract can be carried out directly to the investigated object. The use of very high frequencies of ultrasound provides high image quality with a resolution of less than 1 mm, inaccessible to other research methods (ultrasound, computer tomography and magnetic resonance imaging, endoscopic cholangiopancreatography).

Survey on reconfigurable intelligent surfaces below 10 GHz

Reconfigurable intelligent surface (RIS) is a programmable structure that can be used to control the propagation of electromagnetic waves by changing the electric and magnetic properties of the surface. By placing these surfaces in an environment, the properties of radio channels can be controlled. This opens up new opportunities to improve the performance of wireless systems. In this paper, the basic operation of antenna array and metasurface based RIS is described. While the current long term (6G) research on RIS often prioritizes very high frequencies from tens to hundreds of GHz, this paper puts emphasis rather on operating frequencies below 10 GHz which promise a much faster to market track for RIS applications. For this purpose, review of the literature on the use of RIS in wireless communication applications operating below 10 GHz frequency band is provided.

Numerical study of the propulsive performance of two-dimensional pitching foils at very high frequencies: scaling laws and turbulence effects

Purpose This paper aims to analyze the propulsive performance of small-amplitude pitching foils at very high frequencies with double objectives: to find out scaling laws for the time-averaged thrust and propulsive efficiency at very high frequencies; and to characterize the Strouhal number above which the effect of turbulence on the mean values cannot be neglected. Design/methodology/approach The thrust force and propulsive efficiency of a pitching NACA0012 foil at high reduced frequencies (k) and a Reynolds number Re = 16 000 are analyzed using accurate numerical simulations, both assuming laminar flow and using a transition turbulence model. The time-averaged results are validated with available experimental data for k up to about 12 (Strouhal number, St, up to 0.6). This study also compares the present numerical results with the predictions of theoretical models and existing numerical results. For a foil pitching about its quarter chord with amplitude α0 = 8o, the reduced frequency is varied here up to k = 30 (St up to 2), much higher than in any previous numerical or experimental work. Findings For this pitch amplitude, turbulence effects are found negligible for St ≲ 0.8, and affecting less than 10% to the time-averaged thrust coefficient CT¯ for larger St Linear potential theory fails for very large k, even for the small pitch amplitude considered, particularly for the power coefficient, and therefore for the propulsive efficiency. It is found that CT¯ ∼ St2 for large St, in agreement with recent models, and the propulsive efficiency decays as 1/k, in disagreement with the linear potential theory. Originality/value Pitching foils are increasingly studied as efficient propellers and energy harvesting devices. Their performance at very high reduced frequencies has not been sufficiently analyzed before. The authors provide accurate numerical simulations to discern when turbulence is relevant for the computation of the time-averaged thrust and efficiency and how their scaling with the reduced frequency is affected in relation to the laminar-flow predictions. This is relevant because some small-amplitude theoretical models predict high propulsive efficiency of pitching foils at very high frequencies over certain ranges of the structural parameters, and only very accurate numerical simulations may decide on these predictions.

Resistance of the Montgomery Ladder Against Simple SCA: Theory and Practice

The Montgomery kP algorithm i.e. the Montgomery ladder is reported in literature as resistant against simple SCA due to the fact that the processing of each key bit value of the scalar k is done using the same sequence of operations. We implemented the Montgomery kP algorithm using Lopez-Dahab projective coordinates for the NIST elliptic curve B-233. We instantiated the same VHDL code for a wide range of clock frequencies for the same target FPGA and using the same compiler options. We measured electromagnetic traces of the kP executions using the same input data, i.e. scalar k and elliptic curve point P, and measurement setup. Additionally, we synthesized the same VHDL code for two IHP CMOS technologies, for a broad spectrum of frequencies. We simulated the power consumption of each synthesized design during an execution of the kP operation, always using the same scalar k and elliptic curve point P as inputs. Our experiments clearly show that the success of simple electromagnetic analysis attacks against FPGA implementations as well as the one of simple power analysis attacks against synthesized ASIC designs depends on the target frequency for which the design was implemented and at which it is executed significantly. In our experiments the scalar k was successfully revealed via simple visual inspection of the electromagnetic traces of the FPGA for frequencies from 40 to 100 MHz when standard compile options were used as well as from 50 MHz up to 240 MHz when performance optimizing compile options were used. We obtained similar results attacking the power traces simulated for the ASIC. Despite the significant differences of the here investigated technologies the designs’ resistance against the attacks performed is similar: only a few points in the traces represent strong leakage sources allowing to reveal the key at very low and very high frequencies. For the “middle” frequencies the number of points which allow to successfully reveal the key increases when increasing the frequency.

Fouling Reduction Via Air Backpulsing in Dairy Wastewater Microfiltration

Membrane fouling mitigation in dairy wastewater microfiltration was investigated through air back pulsing. Flat sheet membrane module with pore size of 0.1 mm was used. The model dairy wastewater was prepared by skim milk diluted with distilled water (milk:water = 1:2). The effect of three parameters, including air back pulsing pressure (pb), back pulsing frequency (f), and back pulsing duration (d) on fouling control was investigated. It was found that high pressures of air in short durations of back pulsing can improve the filtration process and result in higher amounts of permeate. However, it is anticipated that beyond the region of study, very high frequency would not be helpful. Very high frequencies mean short back pulsing durations, and this might result in loss of positive effect of back pulsing. The maximum permeate amount obtained using back pulsing assisted filtration process was 83% higher than the one obtained without back pulsing.

Fouling Reduction Via Air Backpulsing in Dairy Wastewater Microfiltration

Membrane fouling mitigation in dairy wastewater microfiltration was investigated through air back pulsing. Flat sheet membrane module with pore size of 0.1 mm was used. The model dairy wastewater was prepared by skim milk diluted with distilled water (milk:water = 1:2). The effect of three parameters, including air back pulsing pressure (pb), back pulsing frequency (f), and back pulsing duration (d) on fouling control was investigated. It was found that high pressures of air in short durations of back pulsing can improve the filtration process and result in higher amounts of permeate. However, it is anticipated that beyond the region of study, very high frequency would not be helpful. Very high frequencies mean short back pulsing durations, and this might result in loss of positive effect of back pulsing. The maximum permeate amount obtained using back pulsing assisted filtration process was 83% higher than the one obtained without back pulsing.

LTCC and Bulk Zn4B6O13–Zn2SiO4 Composites for Submillimeter Wave Applications

New zinc metaborate Zn4B6O13–willemite Zn2SiO4 composites were investigated as promising materials for LTCC (low temperature cofired ceramics) substrates of microelectronic circuits for submillimeter wave applications. Composites were prepared as bulk ceramics and LTCC multilayer structures with cofired conductive thick films. The phase composition, crystal structure, microstructure, sintering behavior, and dielectric properties were studied as a function of willemite content (0, 10, 13, 15, 20, 40, 50, 60, 100 wt %). The dielectric properties characterization performed by THz time domain spectroscopy proved the applicability of the composites at very high frequencies. For the 87% Zn4B6O13–13% Zn2SiO4 composite, the best characteristics were obtained, which are suitable for LTCC submillimeter wave applications. These were a low sintering temperature of 930 °C, compatibility with Ag-based conductors, a low dielectric constant (5.8 at 0.15–1.1 THz), a low dissipation factor (0.006 at 1 THz), and weak frequency and temperature dependences of dielectric constant.