The paper shows the possibility of using a resonant tunneling diode as an optical sensor with a frequency output signal. The resonant tunneling diode was created on the basis of a quantum two-barrier heterostructure, which characterizes the existence of a negative differential resistance in the diode and its microwave properties in the entire radio frequency range. The diode acts both as a primary optical power sensor and as a microwave self-oscillator with an external oscillating LC system, where L and C are the equivalent inductance and equivalent capacitance of the oscillatory system. This greatly simplifies the design of the optical sensor. Using the principle of conversion “optical signal - frequency” can significantly improve the metrological performance of the device. A study of the characteristics of an optical sensor based on its equivalent circuit, which takes into account its inductive and capacitive properties, has been carried out. The current-voltage characteristic has a descending section, causes the appearance of a negative differential resistance, which compensates for energy losses in the oscillatory system of the sensor's self-oscillator. The mathematical model of the sensor is based on the Kirchhoff equations describing the behavior of its equivalent circuit. Analytical dependences of the change in sensor parameters on the effect of optical power on it, as well as the transformation and sensitivity functions, are obtained. It is shown that the main contribution to changes in the conversion functions and sensitivity of the sensor is made by the change in the negative differential resistance under the influence of optical power. This results in a shift in the instrument's output frequency. The sensitivity of the sensor varied from $4.7\times 10^{7} \text{Hz}/\text{mW}$ to $7.4\times 10^{7}\ \text{Hz}/\text{mW}$ in the optical power change range from 1 mW to 10 mW.
Phase composition, microstructure, porosity in the $\text{MgAl}_{2}\mathrm{O}_{4}$ ceramics sintered at 1200 °C for 2 h for sensor applications in electronics were studied using combined methods (X-ray diffraction, scanning electron microscope, Hg-porosimetry, positron annihilation lifetime spectroscopy). It is shown that the obtained ceramics contains three phases. It has a branched structure of grains, intergranular boundaries and pores with trimodal pore size distribution. It is shown that the presence of water in ceramics is accompanied by more intense capture of positrons on defects near the grain boundaries with additional phases. The presence of water in ceramics leads to the fragmentation of the free volume of nanopores and the additional decomposition of ortho-positronium atoms in the adsorbed water.
The development of the multifunctional measurement system for investigation of phosphorescence and optically-stimulated luminescence is described in this paper. The main requirements to be fit are specific for the study of storage phosphors for luminescence dosimetry or those possessing the long lasting (persistent) luminescence, namely: (i) the wide dynamic range of the light flux measurement using the photon counting method, (ii) the ability for precise measurement the glow decay over long time range, (iii) the possibility to use both coherent and non-coherent light sources of high intensity and various wavelengths with options of their combination, (iv) the possibility for spectral and time division of excitation/stimulation of the luminescence and response readout, (v) the easy installation and positioning accuracy of the sample together with its protection from the ambient light in the course of experiments as well as (vi) possibility to heat a sample during luminescence measurement. The component of the system and their operation are described as well as control of the system and data processing used. The modular approach is used to reach a flexible configuration and changeability of system component as well as several methods been tested before are realized in this system for expanding the dynamic range of luminescence glow measurements in photon counting mode.
Radio frequency identification (RFID) technology is widely used for local positioning of objects. The automated monitoring system uses a wireless sensor network and RFID tags that are installed on objects. To determine the RFID tags location, a method based on measuring the received signal strength (RSS measurements) is used. In this work, using expressions for the Cramer-Rao bound, an analysis was performed of the influence of the sensor network configuration on the accuracy of RFID tags location determining based on RSS measurements of the sensor network, which are located around the perimeter of the room. Families of isolines are obtained for sensor network topology containing a different number of sensors. Isolines limit the areas in which the RMS error of positioning does not exceed a certain value. It is shown that the dependence of the RMS error of positioning on the number of sensors in the sensor network has the form of a monotonically decreasing function, asymptotically approaching the steady-state value. Therefore, an excessive increase in the number of sensor network sensors is impractical.
The simulation model of web service with homomorphic cryptosystem is considered. The sizes of ciphertexts and speed of work of existing implementations of homomorphic cryptosystems are determined. The features of implementation of such cryptosystems in web services are researched. Analysis of the speed of modern recommendation systems and homomorphic cryptosystems proved the impossibility of their simultaneous use in web services. It is established that low reliability and slow data processing are associated with the high complexity of the algorithms of these systems.
One of the criteria that can emphasize the importance of cryptological key generators can be related to the number of commercial products and market size in this field. One of these products is Crowd Supply Infinite Noise TRNG hardware. In this study, the cryptographic features of this hardware have been analyzed and its suitability for practical information security applications has been examined. Analyzes have been carried out using the NIST SP 800–22 Statistical Test Suite, which is one of the widely accepted analysis tools in this field. Analysis results revealed that more care should be taken when using information security equipment.
The article analyzes the requirements for information resources coding technologies for UAV and formulates requirements for the method of identifying areas for embedding additional information.
The subject of research is the transmission of video data in information and telecommunications networks. The subject of research is the processes of processing informative segments of the video image using the transformant orthogonal transformation dkp. The aim is to build a technology for coding the sequence of transformants of sufficiently informative image segments while maintaining the efficiency of its delivery at a given informative probability. This will allow, while maintaining structural and statistical legitimacy and controlled loss of quality, to ensure the gain in time to prove compressed video images, the required level of availability and accessibility in the transmission of video data. The solution of the scientific problem aimed at developing methods to reduce the computational complexity of transformations (compression and decompression) of static video images in the equipment for processing signals of visual information, which will increase the efficiency of information delivery. An improved technology for reducing the informative intensity of sufficiently informative image segments has been proposed and studied. It is substantiated that the promising direction of improvement of such technology is the restructuring of dkp transformant components of these segments into several clusters. The technology of processing marker arrays of clustered transformants of sufficiently informative image segments is presented. This provides an opportunity to take into account their dynamic range and statistical redundancy, reduced using the Huffman algorithm. This approach reduces the time of compression and recovery of images; reduce additional statistical redundancy.
In this work we examined the mathematical model of Brusselator previously proved for simulation the epidemic spread by the statistics data for COVID-19 expansion in many countries. Our estimations are in good agreement with statistics for two periods, which are 6 weeks one after another. Comparing changes in the fitting parameters during the 6 weeks for different countries we mentioned that in majority they are very similar, what means the adequacy of the model to the spread of the disease. Besides, carefully testing of the parameters change show the peculiarity of the development of diseases in every country.
The need to ensure prompt (crisis) response to cyber incidents in a limited time determines the improvement of the information model of decision-making. The fundamental impossibility of achieving algorithmic and informational completeness of technical means of cybersecurity involves the implementation of the process of supporting the adoption of appropriate decisions by the operational staff of cybersecurity. Preparation and selection of solutions by the operational staff are based on studying and analyzing information about the state of operation of the object, taking into account the properties of the operating environment in the operational-pragmatic context. The research results show that cybersecurity operators spend 30-60% of the total duration of the decision-making process on the study and understanding of the content of the information model, depending on the level of professional training. One of the best ways to improve the quality of the information model is to add to its content a list of possible solutions that take into account the specific initial conditions of the object and the calculation of the expected effect. The choice of a solution from a set of pre-formed by technical means allows improving the indicators of prompt(crisis) response time in conditions of different professional training of cybersecurity operators. To solve the problem of forming a list of solutions that will be used for responding to the malfunction of the object of cybersecurity, under certain conditions, with the assessment of their effect, it is possible to use methodological approaches to pattern recognition theory which is based on a mathematical model of recognition. Algebraic, linguistic, heuristic, and structural approaches could be used to develop a model of recognition objects. The use of these approaches is associated with some difficulties: the level of formalization of subject areas cannot be the basis for the formation of models of objects of recognition based on classical mathematical canons; the need for significant computing resources that exceed the effect. Given the limitations of the known approaches to building a model for recognizing the state of the object of cybersecurity, the proposal is to study the possibilities of heuristic extension of algorithmic procedures based on the chosen system of fundamental truth.
To solve the problems of proximity assessment, classification and recognition of objects with qualitative features, feature coding using a binary alphabet is often used, and then proximity functions are applied the encoded information Russel and Rao, Sokal and Michener, Jaccard and Needhan etc. However, when coding individual features in real conditions, uncertainties may arise. For example, the color of luminous objects can change continuously. The values of the monitored digital signals in the devices, depending on the modes of their operation, can vary over significant ranges, which can lead to uncertainty in determining their true values and requires the use of alphabets with greater significance to encode them or the use of the mathematical apparatus of fuzzy logic. However, the use of fuzzy logic and multivalued alphabets, in turn, requires modification of the known proximity functions and the development of new computer components for their software implementation.
Analysis of the technical characteristics of aircraft gas turbine engines need the thermal control during their operation. Some malfunctions of the turbojet engine, time of their occurrence, development of defects can be determined at an early stage by the thermal field: destruction of turbine blades, engine rotor disks, bearings, parts of the main and afterburner, etc. Thermal imaging research allows. control the thermal field of the aircraft engine online. It is necessary to take into account the emissivity of the surface; background radiation of foreign objects; radiation and absorption properties of the intermediate medium, operating spectral range. The simulation of the error of radiation temperature measurement from the influence of the intermediate medium and background radiation showed: measurements should be performed in the absence of powerful sources of background radiation, namely in the evening and at night; pre-determine the surface emissivity. The simulation of the intensity of infrared radiation in different spectral ranges showed the feasibility of using a spectral range of $3\div 5\ \mu \mathrm{m}$ for the measuring the temperature gradient and surface temperature and control the functioning of gas turbine engines.
The article describes the methods and techniques proposed to solve the problems that arise when Hall sensors based on gold nanofilms and monolayer graphene are used to measure the magnetic field in extreme conditions of high temperatures and high-energy neutron irradiation. Hardware and software methods and tools for measuring sensor signals in extreme conditions typical for fision and fusion installations are presented.
Cloud computing provides convenient access to abstract computational resources over the Internet. In addition to common services like virtual machines, cloud providers are offering own proprietary domain-specific services and frameworks. The absence of common standards and interfaces makes it difficult to connect services of different clouds, migrate between them, or to distribute tasks across various providers. Extensive research in industry and academia has partially addressed the problem of vendor lock-in for cloud migration, however, no solutions are known to enable running applications in a dynamic multi-cloud infrastructure on a permanent basis. This paper describes state-of-the art of cloud infrastructure and considers the combined usage of multiple providers. It analyses approaches of multi-cloud usage that takes advantage of combining platform-specific features of different cloud providers.
The analysis of fusion methods at the pixel level is carried out in the paper. Their mathematical models in the MATLAB package are implemented. The most effective methods of visible and infrared ranges image fusion are determined by evaluating the effectiveness of methods using the authors' proposed improved method of evaluating the informativeness of images and known metrics. These studies were conducted on a set of test images consisting of ten pairs of spatially synchronized images obtained in the visible and thermal ranges of electromagnetic waves.
In this paper, simulation models of two modified structures of the radar signal frequency monitoring device are presented. The input signal is a reflection from an object moving away from the observation point at a variable velocity. The peculiarity of this signal is the change of frequency and low and variable energy potential. Tracking and failure tracking ranges are defined. The analysis of each of the models was performed for two variants of frequency targeting. The analysis of models of two modified structures of the radar signal receiver showed the possibility and expediency of using these structures in trajectory meters.
The fluxgate probe excitation mode and signal waveforms are considered in the paper. Selected optimal excitation approach from sensitivity and implementation feasibility perspective. Proposed approach implemented in the portable ultra-sensitive digital programmable gradient meter for high-precision archaeological magnetic investigations.
We have researched electrical conductivity, Seebeck coefficient, density of free charge carriers, and their Hall mobility in PbSe - AgSbSe 2 solid monocrystals. The temperature dependence of the electrical conductivity of PbSe - AgSbSe 2 solid solutions in the temperature range 77 – 300 K was studied. We defined the conductivity type of semiconductor and calculated the coefficient of the thermal conductivity PbSe-AgSbSe 2 crystals. We have analyzed the dependence of thermoelectric power and quality factor on the composition of the solid solutions. Discussed possibilities of using given monocrystals as a material for sensitive temperature sensors and thermoelectric generators.
Reducing energy consumption is an important task to this day. Thanks to the development of energy efficiency technologies it was possible to achieve the possibility of using a large number of personal devices. One such technology that has led to the emergence of personal wireless devices (smart watches, headphones, etc.) is BLE (Bluetooth Low Energy) technology. This technology has significantly reduced the use of electricity by the devices with which the devices were developed. Such devices using BLE technology have become widely used in industrial solutions as iBeacons devices. Today, the topic of reducing the energy consumption of these devices is still relevant due to aggressive environments of data use of devices that reduce the life of these devices. The paper presents an algorithm for controlling BLE sensors using an edge device using a deep neural network. An algorithm based on a set of parameters (distance between BLE and Edge devices, priority, and number of current connections) that describe the BLE sensor, calculates the optimal duration of deep sleep of the microcontroller to reduce average power consumption of the device. The main element in this algorithm is a deep neural network, which returns the individual value of deep sleep for the BLE sensor. The new value is written to the corresponding BLE GATT service and characteristic. The simulation allowed to use the BLE sensor battery capacity by almost 20% more efficiently.
A microstrip patch antenna is used due to its advantages in communication systems and for various purposes. However, it suffers from fundamental disadvantages that must be addressed: low gain and low bandwidth. This paper presents a simple, low-cost antenna with a low-profile design suitable for array applications. An increase in gain and dual-band resonance frequency was achieved. The antenna is printed on a substrate with [relative permittivity Er=4.08, thickness = 1.5mm]. and feed using a coaxial prop feed structure. A CST software tool was used for the simulation process. A slotted parasitic antenna achieved high gain and dual bandwidth with linear polarization along the frequency beams. The antenna consists of the main radiator with a parasitic element supported by slot technology. An array of 6 antenna elements is formed with a distance equal to 80 mm to achieve a reflection coefficient S11 <= -22 with gain equal to 13db & 11.6 dB along with the operational bands.
