Multichannel System Research Articles

Low-cost solutions for mobile passive radar based on multichannel DPCA and NULA configurations

Abstract In this paper, we investigate low-cost solutions for enabling ground moving target indication applications with multichannel mobile passive radar systems. As known, in order to be competitive with their active counterparts, passive radars are typically characterized by severe constraints in terms of cost, complexity, and compactness, especially when installed on moving platforms. On the one hand, carrying out the computations onboard requires processing techniques as simple as possible. On the other hand, the need for lightweight and compact systems that can be installed on a moving platform requires using a limited number of receiving channels. To meet these requirements, we propose a series of nonadaptive detectors based on multichannel displaced phase center antennas, which allow suppressing the Doppler-spread clutter component without requiring computationally intensive space–time adaptive processing techniques. Moreover, we explore the use of nonuniformly spaced array configurations on receive, which represent a good alternative to conventional uniform linear arrays when a limited number of receiving channels can be implemented. The effectiveness of the proposed processing techniques and antenna design solutions is demonstrated via numerical analysis for the case of a DVB-T-based mobile passive radar system.

Eight-channel signal synchronous acquisition system based on PCI and LabVIEW

In response to the multi-channel acquisition of the power grid simulator data collection system, this article builds a 8-channel signal synchronization acquisition system based on PCI-1706U and LabView, which introduces the characteristics of PCI-1706U hardware and LabView software DAQ system. A LabView DAQ program that uses the PCI-1706U to collect 8-way signal from the signal generator, complete the experiments of multi-channel synchronous acquisition and delayed start to collection, verify the feasibility and stability of the system, and analyzed the collected signals. Finally, the main work and innovation points of the thesis are summarized, and suggestions and outlook for future improvement are given. This study provides an effective implementation method based on PCI-1706U and LabView multi-channel signal synchronous acquisition system and delay acquisition function, with certain application value and promotion space.

−252.8 °C Liquid Hydrogen Acoustic Emission Experiment in Simulated Aerospace Fuel Tank

With the increase of space activities, the safety detection of equipment in supercold environment becomes more and more important. However, the safety detection of equipment in liquid hydrogen environment is an unsolved worldwide problem. This paper presents a new method to detect acoustic emission (AE) signals in liquid hydrogen environment, which can be used to confirm the safety and reliability of the equipment working in liquid hydrogen. First, the principle of mandrel-based fiber-optic ring (MBFOR) AE sensor and the corresponding demodulation method are introduced. Second, the effects of physical parameters such as the length of the sensing fiber, the diameter and material of the mandrel, and the number of fiber winding layers on the sensor's sensitivity are studied by experiment. Finally, the AE source localization accuracy test of the FOR AE detection system at low temperatures and the adaptability test of the proposed method in -252.8 °C liquid hydrogen are carried out. The results show that the proposed MBFOR sensor and the multi-channel AE detection system can complete the defects detection of aerospace pressure vessel in liquid hydrogen. Certainly, it can be used for safety detection for other spacecraft equipment in harsh environments.

On-scalp Yttrium-Iron Garnet sensor arrays for brain source localization: Cramér-Rao bound analysis

A new type of highly sensitive Magnetometers based on Yttrium-Iron Garnet films (YIGM) is being designed and applied to brain signals recording. We modelled sensor arrays based on YIGM and well-established OPM (QuSpin Inc.) and SQUID (Elekta Neuromag) arrays used for magnetoencephalography (MEG). In this simulation study we investigate the inverse problem accuracy bound depending on the sensor arrays configuration, types of magnetometers and instrumental noise level. We estimate the variance of the probability of dipole source localization using the Cramér-Rao Lower Bound (CRLB); the CRLB is calculated with use of the numerical approximation of the forward model and its partial derivative parametrization. Our models confirm that the development of multi-channel YIG-MEG systems requires noise reduction, rather than an increase in number of sensors, to outperform OPM and SQUID arrays. The modelling showed the advantages of YIG-based gradiometry compared to conventional SQUID-system.

Collaborative biofluid analysis based multi-channel integrated wearable detection system for the monitoring of wound infection

The infection monitoring of chronic wounds can effectively improve the quality of wound care. However, the widely used single variable intermittent monitoring of wound provides little available information, which leads to inaccurate diagnosis and untimely warnings. In this study, a collaborative biofluid analysis based multi-channel integrated wearable detection system was constructed for the continuous detection of analytes such as pH, uric acid (UA), and C-reactive protein (CRP) in wound exudates with time division multiplexing. Based on the functionally modification with nanomaterials, integrated screen-printed electrodes (iSPE) with three working electrodes were designed for the collaboratively analyzing of wound exudates. Through the development of integrated circuits, the multi-channel wearable detection printed circuit board was constructed. With a self-designed interface, this iSPE was stably connected to the printed circuit board and realized the detection of three targets in the range of pH 3–8, UA concentrations 5–500 μmol/L, and CRP concentrations 1–1000 ng/mL at the same time. Combined with a smartphone, these results were collaborated analyzed and transferred for health management. Therefore, this integrated wearable multi-channel detection system can provide reliable and continuous evaluations for early warning of infection and further treatment of chronic wounds.

Research on a Multi-Channel High-Speed Interferometric Signal Acquisition System

In order to capture the large-scale interferometric signal generated by the space-borne interferometric infrared Fourier spectrometer (IRIFS) in real time, and overcome the limitations of insufficient sampling rate, transmission rate, and significant signal noise in current equipment, a multi-channel high-speed acquisition system for large-scale interferometric signals is designed. A high-performance analog-to-digital converter (ADC) oversampling scheme is designed, which can realize up to 8 synchronous acquisition channels and has a maximum sampling rate of 125 Msps/Ch to ensure the acquisition of interferometric signals. The scheme of jesd204b inter-board transmission and optical fiber terminal transmission is designed. The inter-board transmission rate is 12.5 Gbps, and the terminal transmission rate is 10 GB/s to ensure high-speed data transmission. A hardware filter is designed to realize spatial noise processing of interference signals and ensure the accuracy of acquisition results. The dynamic performance of the data acquisition (DAQ) card is analyzed using discrete Fourier transform in the frequency domain. The spurious free dynamic range (SFDR) is 84 dB, the signal-to-noise ratio (SNR) is 72.7 dB, and the cross-talk is −81.6 dB, which verifies the dynamic stability of the DAQ card. Finally, the infrared radiation in real space is measured. The average ΔNESR of long wave reaches 48 mW∗m−2∗sr−1, and the average ΔNESR of medium wave reaches 12.3 mW∗m−2∗sr−1, which verifies the reliability of the system performance. The system is of great significance for large-scale infrared interferometric signal acquisition, and has strong practical application value in multi-channel synchronization, real-time high-speed acquisition, and high-speed data transmission.

A Custom-Tailored Multichannel Pressure Monitoring System Designed for Experimental Surgical Model of Abdominal Compartment Syndrome.

In experimental medicine, a wide variety of sensory measurements are used. One of these is real-time precision pressure measurement. For comparative studies of the complex pathophysiology and surgical management of abdominal compartment syndrome, a multichannel pressure measurement system is essential. An important aspect is that this multichannel pressure measurement system should be able to monitor the pressure conditions in different tissue layers, and compartments, under different settings. We created a 12-channel positive-negative sensor system for simultaneous detection of pressure conditions in the abdominal cavity, the intestines, and the circulatory system. The same pressure sensor was used with different measurement ranges. In this paper, we describe the device and major experiences, advantages, and disadvantages. The sensory systems are capable of real-time, variable frequency sampling and data collection. It is also important to note that the pressure measurement system should be able to measure pressure with high sensitivity, independently of the filling medium (gas, liquid). The multichannel pressure measurement system we developed was well suited for abdominal compartment syndrome experiments and provided data for optimizing the method of negative pressure wound management. The system is also suitable for direct blood pressure measurement, making it appropriate for use in additional experimental surgical models.

Evoked compound action potential (ECAP)-controlled closed-loop spinal cord stimulation in an experimental model of neuropathic pain in rats

BackgroundPreclinical models of spinal cord stimulation (SCS) are lacking objective measurements to inform translationally applicable SCS parameters. The evoked compound action potential (ECAP) represents a measure of dorsal column fiber activation. This measure approximates the onset of SCS-induced sensations in humans and provides effective analgesia when used with ECAP-controlled closed-loop (CL)-SCS systems. Therefore, ECAPs may provide an objective surrogate for SCS dose in preclinical models that may support better understanding of SCS mechanisms and further translations to the clinics. This study assessed, for the first time, the feasibility of recording ECAPs and applying ECAP-controlled CL-SCS in freely behaving rats subjected to an experimental model of neuropathic pain.MethodsAdult male Sprague–Dawley rats (200–300 g) were subjected to spared nerve injury (SNI). A custom-made six-contact lead was implanted epidurally covering T11-L3, as confirmed by computed tomography or X-ray. A specially designed multi-channel system was used to record ECAPs and to apply ECAP-controlled CL-SCS for 30 min at 50 Hz 200 µs. The responses of dorsal column fibers to SCS were characterized and sensitivity towards mechanical and cold stimuli were assessed to determine analgesic effects from ECAP-controlled CL-SCS. Comparisons between SNI rats and their controls as well as between stimulation parameters were made using omnibus analysis of variance (ANOVA) tests and t-tests.ResultsThe recorded ECAPs showed the characteristic triphasic morphology and the ECAP amplitude (mV) increased as higher currents (mA) were applied in both SNI animals and controls (SNI SCS-ON and sham SCS-ON). Importantly, the use of ECAP-based SCS dose, implemented in ECAP-controlled CL-SCS, significantly reduced mechanical and cold hypersensitivity in SNI SCS-ON animals through the constant and controlled activation of dorsal column fibers. An analysis of conduction velocities of the evoked signals confirmed the involvement of large, myelinated fibers.ConclusionsThe use of ECAP-based SCS dose implemented in ECAP-controlled CL-SCS produced analgesia in animals subjected to an experimental model of neuropathic pain. This approach may offer a better method for translating SCS parameters between species that will improve understanding of the mechanisms of SCS action to further advance future clinical applications.

Scalable and Multi-Channel Real-Time Low Cost Monitoring System for PEM Electrolyzers Based on IoT Applications

This paper discusses and evaluates a novel multi-channel real-time architecture aimed at monitoring a Proton Exchange Membrane (PEM) electrolyzer, both at the individual cell and stack levels. The proposed solution includes two primary subsystems: a hardware subsystem dedicated to data acquisition (DAQ) and a software subsystem focused on monitoring purposes. The DAQ subsystem utilizes an Arduino platform, being an affordable and open-source solution. The real-time monitoring data can be encoded in JSON format, widely used as a light-weight inter-exchange data format between a variety of IoT applications. They are also available to be transferred to Excel. Indeed, and to enhance convenience, the proposed system integrates graphs displaying a template based on Excel spreadsheets, which are commonly used in industrial environments. The current, voltage, temperature, and pressure data of both individual cells and stacks were monitored and collected, being configurable under a variety of ranges. As a case study, the validation of the system involved static and dynamic operational modes using a 1.2 kW PEM electrolyzer prototype (100 A, 1 A/cm2). The results successfully provided the monitored variables across individual cells and within the stack. The proposed approach exhibits relevant key characteristics such as scalability, flexibility, user-friendliness, versatility, and affordability and are suitable to monitor PEM electrolyzers in real-time at both the cell and stack levels.

Chat service in a multichannel system under competition where customers are boundedly rational

Many service systems in various type of industry provide services via chat technologies. This type of service system is characterized by an interesting combination of properties. First, the customer is actively involved in service execution, since the service is comprised of responses of the server and the customer to each other, until the customer's request is satisfied. In addition, in such a system, the service can be provided by a single server in a parallel manner to a number of customers. Motivated by these and others interesting properties of the chat service, we formulate and analyze the stochastic queueing system as a two-dimensional quasi-birth-and-death process and derive its steady-state probabilities using matrix geometric methods. By means of economic analysis, we provide a scheme for deriving the optimal capacity of parallel chats and the optimal response effort that should be made by the server, considering that higher effort lengthens the response time but increases the probability of successful service completion. We next investigate a queueing game that considers a multi-channel service system consisting of a chat service and a traditional multi-server call center, and we consider strategic customers under both a centralized and a decentralized scenario. We show that competition between service channels may lead to lower service utilization even though customers enjoy higher expected utility. Finally, customer bounded rationality is considered and it is shown that customers who are less rational may enjoy higher utility. Sensitivity analyses are conducted for all scenarios.

Multi-channel gas-diesel engine control system based on jet-convective sensors

Accurate measurement of the dynamic flow rate of the components of the gas-fuel mixture is required in electronic automatic control systems of the internal combustion engine. The paper substantiates the structural construction of the measurement channels of the multi-channel gas-diesel engine control system. In the implementation of the measurement channels, special attention is paid to the structure of the jet-convective channel for obtaining an informative signal on the gas fuel flow rate and the structure of the ion-labeled channel for measuring the air flow rate. Application of jet-convective transducers is supplemented by the original structural scheme of primary signals processing, which will allow expanding the measurement range towards low flow rate values, increasing the speed and reducing the random component of the error.

Optimal DoS attack on multi-channel cyber-physical systems: A Stackelberg game analysis

In this commentary, optimal denial-of-service (DoS) attack strategies on multi-channel cyber-physical systems (CPSs) are considered, which focus on energy allocation on communication channels. For simplicity, a Stackelberg game between one defender and one attacker is constructed. Compared with the existing literature, which mainly pay attention to static equilibrium, the dynamic process of the game is also exhibited in this paper, which fills the gap in the demonstration of dynamic decision-making between both players of the game. In the solution of Stackelberg equilibrium, a self-adaptive particle swarm optimization (PSO) algorithm with Sigmoid-like update function is applied to cope with the nonlinearity of the reward function with faster convergence and wider adaptability. Besides, to acquire better performance of both sides to allocate energy, an online computation algorithm is proposed for dynamic Stackelberg game. Finally, numerical examples are provided to illustrate similarities between theoretic static equilibrium and optimal strategies obtained by Monte Carlo simulations.

Ambient catalyst-free oxidation reactions of aromatic amines using water radical cations.

Water radical cations play a pivotal role in various scientific and industrial fields due to their unique reactivity and capacity to drive complex chemical transformations. Here we explored the formation of quaternary ammonium cations through the direct oxidation reaction of aromatic amines, facilitated by water radical cations within water microdroplets. This process was monitored via in situ mass spectrometry and occurs under ambient conditions, negating the need for traditional chemical catalysts or oxidants and achieving an impressive yield of approximately 80%. Additionally, we employed a multi-channel spray system and enhanced both the reactant concentration and flow rate, thereby enabling gram-scale synthesis. These findings not only demonstrate the effectiveness and eco-friendliness of microdroplet chemistry but also provide a new understanding of heterogeneous ˙OH generation channels, thereby boosting the synthetic efficiency and sustainability of chemical processes.

МОДЕЛЬ И МЕТОДИКА ИССЛЕДОВАНИЯ СКВОЗНОГО БИЗНЕС-ПРОЦЕССА В ТАМОЖЕННОЙ ЭКОСИСТЕМЕ

This article provides a detailed examination of the operations occurring in the customs system aimed at conducting documentary and actual customs control. The average volume of loads processed by a particular element of the customs ecosystem, as well as the average time spent by a declaration at each stage of customs clearance, were calculated, the main parameters reflecting the productivity of the subsystem elements were determined, and a model of a multi-channel mass service system was built to determine the average time spent by a declaration of goods in various subsystems (customs offices, customs offices of direct subordination, regional customs administrations).

Design of multi-channel sequential front light imaging system for transient condition

Design of multi-channel sequential front light imaging system for transient condition

Cooperative Control of Multi-Channel Linear Systems with Self-Organizing Private Agents

Cooperative Control of Multi-Channel Linear Systems with Self-Organizing Private Agents

Cost‐Efficient Network Design in Multichannel WSNs With Power Control: A Grey Wolf Optimization Approach to Routing and Clustering

Wireless sensor networks (WSNs) require optimized energy consumption and an improved packet delivery ratio (PDR) for optimal performance. Clustering and routing strategies are frequently used to reduce energy usage, while multiradio (MR) multichannel (MC) systems improve PDR levels. Transmission power control (TPC) features in both energy consumption reduction and PDR improvement. While the mentioned techniques are used in previous studies, they were investigated separately and without a holistic approach. This study discusses the challenge of obtaining high‐PDR, energy‐efficient, and cost‐effective clustering and routing in WSNs. As a means of reducing deployment costs, a heterogeneous setting with energy‐constraint normal sensors for environmental monitoring as well as some high‐energy, TPC‐enabled, MR super nodes is assumed. The super nodes are considered as CHs and are responsible for collecting the sensed data from the normal sensors. Installing additional radios on super nodes enables static channel assignment (CA), which yields high PDR with low imposed overhead on the network. The mentioned TPC‐based MC heterogeneous setting, which yields cost‐effectiveness, high PDR, and energy efficiency, was not investigated in previous studies. The considered problem is decoupled into two phases of configuring the super nodes and normal sensors, which are solved using the grey wolf optimization (GWO) algorithm. The performed simulations show an average improvement of our proposed algorithm in PDR, energy consumption, consumed energy per delivered bit, and network lifetime by 9%, 30%, 65%, and 44%, respectively.

68-channel neural signal processing system-on-chip with integrated feature extraction, compression, and hardware accelerators for neuroprosthetics in 22 nm FDSOI.

Multi-channel electrophysiology systems for recording of neuronal activity face significant data throughput limitations, hampering real-time, data-informed experiments. These limitations impact both experimental neurobiology research and next-generation neuroprosthetics. We present a novel solution that leverages the high integration density of 22nm fully-depleted silicon-on-insulator technology to address these challenges. The proposed highly integrated programmable System-on-Chip (SoC) comprises 68-channel 0.41 μW/Ch recording frontends, spike detectors, 16-channel 0.87-4.39 μW/Ch action potentials and 8-channel 0.32 μW/Ch local field potential codecs, as well as a multiply-accumulate-assisted power-efficient processor operating at 25 MHz (5.19 μW/MHz). The system supports on-chip training processes for compression, training, and inference for neural spike sorting. The spike sorting achieves an average accuracy of 91.48 or 94.12% depending on the utilized features. The proposed programmable SoC is optimized for reduced area (9 mm2) and power. On-chip processing and compression capabilities free up the data bottlenecks in data transmission (up to 91% space saving ratio), and moreover enable a fully autonomous yet flexible processor-driven operation. Combined, these design considerations overcome data-bottlenecks by allowing on-chip feature extraction and subsequent compression.

Low-noise multi-channel underwater electric field measurement and analysis system for a ship model.

The underwater electric field (UEF) signature of a ship is a key factor in its survivability in marine warfare. Moreover, the study of a ship's UEF using scale models of ships in pools can be useful for the design of electromagnetically stealthy ships. Aiming at the system requirement of measuring and analyzing the UEF of scale models of ships with low noise, many channels, and real-time responsivity, we developed a system consisting of electrode sensors, a measuring device, and a personal computer (PC). Small Ag/AgCl electrodes with low noise and high stability were used. The measuring device was capable of simultaneously amplifying, sampling, and storing 24 channels of UEF data in real-time, and it was connected to the PC via Ethernet to facilitate the transfer of UEF data at high speeds. The PC software could display 24 low-frequency UEF curves in real time and perform spectral analysis and filtering of the UEF signals. In system performance tests, we found that the system had a noise floor lower than 6.34 nV/rt(Hz)@1Hz and could simultaneously sample 24 channels of UEF signals while storing, displaying, and analyzing the signals in real-time. The primary functions of the system were also validated in a pooled experiment.

Wireless single-electrode electrochemiluminescence device based on wireless reverse charging or on-the-go USB transmission for multiplex analysis.

A wireless electrochemiluminescence (ECL) device employing the wireless reverse charging function or on-the-go (OTG) USB transmission function of smartphones is designed. It was coupled with a multi-channel single-electrode electrochemical system based on the resistance-induced potential difference for multiple ECL analyses using a smartphone as the detector.