Using CME and FCME Algorithms for the Task of Detecting Human Steps

Currently, global trends in the development of perimeter security technology lead to the general miniaturization of devices and systems and the increase of their autonomy. The primary trend in developing these systems is the maximum processing and classification of signals by built-in tools. The article presents the study results on the possibility of using blind algorithms to calculate the level of operation of the threshold detector CME and FCME in detecting human steps in seismic perimeter security detectors using low-power computing modules. The algorithms were tested on actual data recorded during the experiments. As a result of applying algorithms for the seismic signal envelope, the human steps of the probability of false positives for the CME and FCME algorithms were 23% and 10%, respectively. Neutralizing the signal trend allowed obtaining values of false alarms of 16% for the CME algorithm and 7% for the FCME algorithm, and normalization of the signal amplitude within one analysis interval allowed obtaining the probability of false alarms at 0% for both algorithms. The obtained results give complete information when choosing the type of algorithm depending on the input data. In detecting seismic data by an autonomous sensor, it is most appropriate to use the SME algorithm with pre-normalization of the signal amplitude due to less computational complexity.

On some applications of vibrational resonance on noisy image perception: the role of the perturbation parameters

In this paper, we first propose a brief overview of nonlinear resonance applications in the context of image processing. Next, we introduce a threshold detector based on these resonance properties to investigate the perception of subthreshold noisy images. By considering a random perturbation, we revisit the well-known stochastic resonance (SR) detector whose best performances are achieved when the noise intensity is tuned to an optimal value. We then introduce a vibrational resonance detector by replacing the noisy perturbation with a spatial high-frequency signal. To enhance the image perception through this detector, it is shown that the noise level of the input images must be lower than the optimal noise value of the SR-based detector. Under these conditions, considering the same noise level for both detectors, we establish that the vibrational resonance (VR)-based detector significantly outperforms the SR-based detector in terms of image perception. Moreover, we show that whatever the perturbation amplitude, the best perception through the VR detector is ensured when the perturbation frequency exceeds the image size. This article is part of the theme issue ‘Vibrational and stochastic resonance in driven nonlinear systems (part 2)’.

Relay-Assisted Satellite QKD Systems using MMW Radio-over-FSO for Vehicular Networks

This paper aims at proposing a novel satellite quantum key distribution (QKD) system for vehicular networks. Quantum key from a satellite (i.e., a trusted node) is transmitted through a free-space optical (FSO) channel to a high-attitude platform (HAP) using radio-over-FSO (RoFSO) technique. HAP playing a role as a relaying node forwards the key to moving vehicles via millimeter-wave (MMW) channel. Key information generated is encoded on MMW subcarrier using binary phase shift keying (BPSK) signaling and then recovered at the receiver thanks to a dual-threshold detector. We derive the mathematical expressions for security analysis of the proposed QKD system in terms of quantum bit error rate and ergodic secret-key rate taking into account the channel loss and receiver noise. The numerical results confirm the feasibility of the proposed QKD system.

Radar signal processing algorithm and simulation of detection system

With its unique array arrangement, the detection system radar has both space diversity gain and waveform diversity gain, and is currently recognized as a stealth target buster. The detection system radar is applied to a high-speed moving platform. Using distributed cooperative detection technology, non-coherent fusion detection based on signals can further improve the detection of stealthy targets. Aiming at the high-speed motion radar signal processing algorithm, this paper mainly studies the following three aspects: the first content is the analysis of the waveform characteristics: the basic principles and characteristics of the radar are explained; then the three orthogonal waveforms commonly used in the radar are introduced, including Stepwise frequency division chirp signal, quadrature phase coded signal and mixed-signal; the second content detects radar targets and analyzes the correlation between the scattering coefficients of different radar channels; for scenarios where the scattering coefficients between the channels are non-coherent Introduced two kinds of non-coherent fusion detectors based on generalized likelihood ratio algorithm: centralized detector and double threshold detector; the third content radar multi-target pairing is aimed at the problem of radar multi-target pairing with large inertial navigation error. A multi-target pairing algorithm that uses target delay information and combines the radar’s multi-channel information redundancy characteristics is presented. An expression for judging the correctness of target pairing is derived, and the target pairing steps are given. The relationship between the amount of algorithm operation and the number of radar stations and the number of targets is analyzed in conclusion.

Two Novel Current-Mode CNFET-Based Full Adders Using ULPD as Voltage Regulator

This paper presents two novel current-mode Full Adders based on Carbon Nanotube FET (CNFET). They comprise of three main parts: current-to-voltage converter, threshold detector and voltage-to-current converter. While other designs in the literature use either inverter or current source for detecting threshold, the new designs are based on a heuristic usage of an Ultra Low-Power Diode (ULPD) as voltage regulator. The use of diode does not lengthen the critical path and thereby ensuring high-speed operation. It does not increase power consumption significantly either. Simulation results by HSPICE and 32[Formula: see text]nm CNFET technology file demonstrate at least 19% higher performance in terms of energy consumption for the second proposed Full Adder compared to other traditional and state-of-the-art current-mode and mixed-mode designs.

Triggering parametric-down conversion-based quantum key distribution via radiation field

We discuss the influence of radiation field on the secure key size and the maximum safety distance during QKD by using a set of photons produced via a spontaneous parametric-down conversion (SPDC) photon source. Four implementations that use multiple-photons and decoy states are discussed, these include nondecoy state, infinite active decoy state, passive decoy state with threshold detector and passive decoy state with perfect photon-number resolving detector. Results show that the radiation field significantly improves both the secure key size and the maximum secure communication distance. Therefore, the radiation field is found to be a good candidate to reduce unwanted interactions of photons with the quantum channel and hence, to increase the secure key rate and the maximum safety distance between legitimate users.

Microwave photon detection by an Al Josephson junction

An aluminium Josephson junction (JJ), with a critical current suppressed by a factor of three compared with the maximal value calculated from the gap, is experimentally investigated for application as a threshold detector for microwave photons. We present the preliminary results of measurements of the lifetime of the superconducting state and the probability of switching by a 9 GHz external signal. We found an anomalously large lifetime, not described by the Kramers’ theory for the escape time over a barrier under the influence of fluctuations. We explain it by the phase diffusion regime, which is evident from the temperature dependence of the switching current histograms. Therefore, phase diffusion allows for a significant improvement of the noise immunity of a device, radically decreasing the dark count rate, but it will also decrease the single-photon sensitivity of the considered threshold detector. Quantization of the switching probability tilt as a function of the signal attenuation for various bias currents through the JJ is observed, which resembles the differentiation between N and N + 1 photon absorption.

If an analogue fire detector is analogue one

Предметом рассмотрения в статье являются термины, применяемые в системе пожарной сигнализации. Обращается внимание на несоответствие общепринятого определения термина «аналоговый пожарный извещатель» его смысловому содержанию. Это несоответствие нередко является причиной недопонимания потребителями пожарно-технической продукции особенностей аналоговых пожарных извещателей и их отличий от пороговых. Предлагается называть извещатели с функцией обработки сигнала интеллектуальными, не отказываясь в определенных случаях от использования термина «аналоговый пожарный извещатель». The simplest fire detectors contain a sensitive element that controls a certain physical parameter of the environment, which changes when a fire occurs. When this parameter reaches the set threshold value, the detectors generate an alarm signal perceived by the control equipment (control panel). When using this algorithm, the decision to detect a fire is made by the fire detector, which is called the threshold detector. One of the significant drawbacks of such an algorithm is the inability to track the dynamics of changes in the controlled environment parameter, which often causes the fire detector to form a false signal. In the 60s and 70s of the 20th century, when digital technology was widely developed, a different fire detection algorithm was proposed. Only an analog-to-digital converter was installed in the fire detector. The real-time digitized value of the monitored parameter was broadcast in serial code to the control panel. All elements of memory and mathematical processing were part of this panel. As a result, the fire detector became, in fact, a sensor that transmits the measured readings on the control equipment, and the decision to register a fire was made not in the detector, but in the control panel. This type of fire detector is called “analogue”. The main advantage of analogue detectors was the reduction in the likelihood of a false alarm being generated by the fire alarm system. On the current level of digital technology development, the concept of «analogue fire detector» for the most part loses its meaning. The development of digital technology has led to the global miniaturization of electronic components and reduced their energy consumption. Under these conditions, the need to transmit information about the controlled factor of fire to control panel without preliminary data processing in the detector itself disappeared. Currently, the concept of “analogue” fire alarm systems in the semantic meaning of the term “analogue”, which was used at the beginning of digital technology development, has changed the meaning. Almost all modern fire detectors can be considered as threshold because they take decision on the need to generate an alarm signal transmitted to the control panel.