Efficiency Of Signal Transmission Research Articles

Price spillovers and interdependences in China's agricultural commodity futures market: Evidence from the US-China trade dispute

We examine the effects of the US-China trade dispute on price spillovers and interdependencies among the ten most liquid agricultural futures contracts traded on China's commodity exchanges by employing the time-varying connectedness framework modified by Antonakakis, Chatziantoniou, and Gabauer (2020). We find that the overall market frictions increase modestly due to the clustering of mixed informational disturbances caused by the trade dispute. This lowers the gross spillovers in the entire asset system by reducing the efficiency of general price signal transmission. Notably, subsidiary products of rapeseed and soybean contribute the most to the total and net directional spillovers in the whole market, acting as shock transmitters before the trade dispute. The RBD palm market gains a dominant role as a shock transmitter during the trade dispute and its role strengthens further after the trade agreement was reached. Additionally, the average intensity of pairwise spillovers declines considerably during the trade dispute, suggesting weakening asset interconnectedness. The responsiveness of shock transmission channels to the trade dispute impacts is found to vary across industrial chains and the presence of delayed economic effects is detected in the structural changes of market interdependences.

Cell‐Anchored Lead‐Free Piezoelectric KNN NPs Resisting Washout for Low‐Intensity Ultrasound Driven Neuromodulation

AbstractPiezoelectric nanomaterials for wireless neuromodulation is a promising alternative to traditional electrical stimulation. However, the low‐avidity between piezoelectric nanomaterials and cellular membranes leads to low efficiency of electrical signal transmission, which requires high‐intensity thresholds of ultrasound stimulation (US). Here, lead‐free piezoelectric (K,Na)NbO3 (KNN) nanoparticles (NPs) with cholesterol coating (KNNC) are presented, in which Cholesterol can be accommodated in the membrane and make them append on the plasma membrane. Compared to non‐modified nanoparticles, cell‐anchored KNNC NPs highly resist convective washout owing to high affinity of cholesterol to biological membranes, which enables highly efficient wireless electrical stimulation to activate cell impulses under low‐intensity ultrasound. Meanwhile, after perfusion washing, the KNNC NPs distributed around the cells are washed away, while part of KNNC NPs remain on the surface of cell membrane still can induce significant Ca2+ influx under US, similar to the group without washing, indicating the KNNC NPs appended on the cell play a major role in wireless electrical stimulation. Furthermore, the highly efficient electrical transmission of KNNC enables neural differentiation of stem cells in regulating synaptic plasticity by modulating Ca2+ influx, demonstrating that KNNC NPs offer a perspective toward minimally invasive wireless neuromodulation therapies for neurological diseases.

Small-size temperature/high-pressure integrated sensor via flip-chip method

Hydraulic technology with smaller sizes and higher reliability trends, including fault prediction and intelligent control, requires high-performance temperature and pressure-integrated sensors. Current designs rely on planar wafer- or chip-level integration, which is limited by pressure range, chip size, and low reliability. We propose a small-size temperature/high-pressure integrated sensor via the flip-chip technique. The pressure and temperature units are arranged vertically, and the sensing signals of the two units are integrated into one plane through silicon vias and gold–gold bonding, reducing the lateral size and improving the efficiency of signal transmission. The flip-chip technique ensures a reliable electrical connection. A square diaphragm with rounded corners is designed and optimised with simulation to sense high pressure based on the piezoresistive effect. The temperature sensing unit with a thin-film platinum resistor measures temperature and provides back-end high-precision compensation, which will improve the precision of the pressure unit. The integrated chip is fabricated by MEMS technology and packaged to fabricate the extremely small integrated sensor. The integrated sensor is characterised, and the pressure sensor exhibits a sensitivity and sensitivity drift of 7.97 mV/MPa and −0.19% FS in the range of 0–20 MPa and −40 to 120 °C. The linearity, hysteresis, repeatability, accuracy, basic error, and zero-time drift are 0.16% FS, 0.04% FS, 0.06% FS, 0.18% FS, ±0.23% FS and 0.04% FS, respectively. The measurement error of the temperature sensor and temperature coefficient of resistance is less than ±1 °C and 3142.997 ppm/°C, respectively. The integrated sensor has broad applicability in fault diagnosis and safety monitoring of high-end equipment such as automobile detection, industrial equipment, and oil drilling platforms.

Resource allocation and OFDM system transmission for 5G cellular communications

Cellular communication technology has been developed for over a hundred years and has reached its fifth generation in mobile. 5G, as a new generation of communication technology, has comprehensively changed the mobile network application model with its ability of high-speed transmission, low network latency, and large-scale connectivity. It has brought a new impetus to the development of various industries. Cellular communication uses cellular wireless networking to connect terminals and network devices through wireless channels so that users can communicate with each other during their activities, with the main feature being the mobility of the terminals and the automatic roaming process across local networks. The use of OFDM in 5G communications can significantly improve the efficiency and capacity of wireless signal transmission. This paper provides a detailed introduction to the use of OFDM in cellular communications through frequency division multiplexing and OFDM.

Prototype of High-Speed Data Transmission Receiving and Transmitting Equipment in the 57‒64 GHz Frequency Range

The purpose of this work is to create and study the characteristics of a prototype of receiving and transmitting equipment operating in the millimeter wavelength range in high-speed data transmission networks. During the work, the task of developing and software implementation of digital signal processing algorithms was solved, the hardware part was developed and implemented, experimental measurements of characteristics and field tests of the prototype were carried out. Experimental studies have shown that the developed equipment transmits and receives signals in the frequency range 57‒64 GHz with the possibility of discrete change of the signal frequency bandwidth: 100, 200, 400, 800 MHz and supports 12 modulation and coding schemes with low-density parity check code. The use of an adaptive algorithm for demodulation and decoding at the receiver made it possible to increase the efficiency of signal transmission and reduce the probability of packet errors by half. The developed prototype provides a data transmission rate of 2 Gbit/s at distances up to 100 m and of 500 Mbit/s at distances up to 300 m.

Numerical Analysis of the New Wireless Relay Transmission Model Based on FEM

In this article, a wireless relay transmission system in long-distance wells with new close winding helical coils is proposed. This system can realize more efficient bottom-up superposition transmission of signals in long transmission wells. At the same time, by redesigning the structure of the transmitting and relay antennas, a close winding helical coil structure with metal ring protection is proposed to excite quasi-TEM waves, which improves the efficiency of signal transmission in each channel and the compressive strength of the antenna. The simulation and experimental results demonstrate that under long distance and harsh stratum conditions, the wireless transmission system in long-distance wells has excellent signal transmission performance at extremely low frequencies. Compared with previous antenna structures, the new helical coil has better performance in transmission efficiency. This new wireless relay transmission system can greatly meet the long-distance transmission and conditions of oil and gas wells in the future.

Synergetic Effect of Electrical and Topographical Cues in Aniline Trimer-Based Polyurethane Fibrous Scaffolds on Tissue Regeneration.

Processibility and biodegradability of conductive polymers are major concerns when they are applied to tissue regeneration. This study synthesizes dissolvable and conductive aniline trimer-based polyurethane copolymers (DCPU) and processes them into scaffolds by using electrospinning with different patterns (random, oriented, and latticed). The effects of topographic cue changes on electrical signal transmission and further regulation of cell behaviors concerning bone tissue are researched. Results show that DCPU fibrous scaffolds possessed good hydrophilicity, swelling capacity, elasticity, and fast biodegradability in enzymatic liquid. In addition, the conductivity and efficiency of electrical signal transmission can be tuned by changing the surface's topological structure. Among them, oriented DCPU scaffolds (DCPU-O) showed the best conductivity with the lowest ionic resistance value. Furthermore, the viability and proliferation results of bone mesenchymal stem cells (BMSCs) demonstrate a significant increase on three DCPU scaffolds compared to AT-free scaffolds (DPU-R). Especially, DCPU-O scaffolds exhibit superior abilities to promote cell proliferation because of their unique surface topography and excellent electroactivity. Concurrently, the DCPU-O scaffolds can synergistically promote osteogenic differentiation in terms of osteogenic differentiation and gene expression levels when combined with electrical stimulation. Together, these results suggest a promising use of DCPU-O fibrous scaffolds in the application of tissue regeneration.

History and Future Directions of rTMS for Treatment of Depressive Disorders

History and Future Directions of rTMS for Treatment of Depressive Disorders

Reducing the impact of interchannel interference on the efficiency of signal transmission in telecommunication systems of data transmission based on the ofdm signal

This paper considers the process that forms an interchannel transient interference in the structure of the signal created on the basis of the technology of parallel data transmission and frequency distribution with multiplexing of the phase-modulated signal – the OFDM signal. Based on the analysis of the OFDM signal structure, it was determined that changes in the position and parameters of the carrier symbol from the composition of this OFDM symbol create an interchannel transient interference. A list of OFDM signal parameters that can affect the appearance of interchannel interference and the value of its quantitative value was summarized and presented. A model for assessing the impact of interchannel interference on the efficiency of signal transmission in telecommunication data transmission systems based on the OFDM signal has been developed and proposed. Based on mathematical modeling using this model, the dependence of the quantitative assessment of the magnitude of the interchannel interference on the magnitude of the protective interval for different values of the interchannel value with a different number of signal pre-reception has been established. It is shown that an increase in the value of the interchannel value to 96 subchannels makes it possible to achieve an interchannel transient interference of less than 3 percent with a protective interval of more than 2 ms already with one pre-reception. This is explained by the fact that the increase in the interchannel value makes it possible to reduce the value of the protective interval and minimizes the effect of frequency distortions of the sub-channel of one channel. The data reported in this work and the recommendations substantiated on their basis confirm the possibility of the proposed model for assessing the value of the interchannel transient interference and justifying the recommendations for reducing its impact on the efficiency of signal transmission in telecommunication data transmission systems based on the OFDM signal. The proposed evaluation model can find practical application in improving existing and developing new telecommunication data transmission systems based on OFDM technology

Electrical Characterization of Through-Silicon-via-Based Coaxial Line for High-Frequency 3D Integration (Invited Paper)

Through-silicon-via (TSV)-based coaxial line techniques can reduce the high-frequency loss due to the low resistivity in the silicon substrate and thus can improve the efficiency of vertical signal transmission. Moreover, a TSV-based coaxial structure allows easily realizing the impedance matching in RF/microwave systems for excellent electrical performance. However, due to the limitations of existing available dielectric materials and the difficulties and challenges in the manufacturing process, ideal coaxial TSVs are not easy to obtain, and thus, the achieved electrical performance might be unexpected. In order to increase the flexibility of designing and manufacturing TSV-based coaxial structures and to better evaluate the fabricated devices, modeling and analysis theories of the corresponding high-frequency electrical performance are proposed in the paper. The theories are finally well validated using the finite-element simulation results, hereby providing guiding rules for selecting materials and improving manufacturing techniques in the practical process, so as to optimize the high-frequency performance of the TSV structures.

Near-Reflectionless Wireless Transmission Into the Body With Cascaded Metasurfaces

The ability to transmit wireless signals into the body is important for medical communication, sensing, and powering technologies. However, the efficiency of signal transmission is limited by the large reflection encountered at the interface between air and biological tissue. Here, we demonstrate an approach to overcome this reflection using cascaded metasurfaces (MSs) with deeply subwavelength thickness to transform the wave impedance at the air–tissue interface. We develop a procedure to systematically synthesize these MSs using a multilayer tissue model that can account for different body compositions. Using this procedure, we design a three-layer MS operating at 2.45 GHz with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda /24.5$ </tex-math></inline-formula> thickness. Full-wave simulations in a computational human body model show that the MS provides transmission equivalent to replacing the background with a tissue-matched medium, while experimental measurements demonstrate 12.1 dB enhancement of transmission into a multilayer tissue phantom.

Wide-Stopband Substrate Integrated Waveguide Filter Power Divider Based on Through Glass Quartz Via (TQV) Technology

This article presents a substrate integrated waveguide (SIW) filter power divider (FPD) based on glass substrate with a wide stopband. Couplings of TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">101</sub> and TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">103</sub> modes construct the passband of the FPD, which are transmitted by a T-type structure with resonators of different sizes to reduce parasitic patterns. The input and output ports are realized by electrical feeders, which penetrate into the center of resonant cavity. Combined with the lateral coupling structure, the parasitic passband caused by the even-high-order modes can be eliminated effectively. Utilizing the multimode transmission characteristics of waveguide resonators, electromagnetic waves of two modes are set to transmit in resonators of different sizes, effectively suppressing the resonance of higher order modes. In order to achieve a good isolation, an isolation resistor is introduced between two output ports to ensure the high efficiency of signal transmission. Consequently, an FPD with a center frequency of 35.5 GHz, a bandwidth of 1 GHz, and out-of-band suppression greater than six times the center frequency is designed, fabricated, and measured. Both theory and experiment have proved the effectiveness of the above method, and the simulation results are in good agreement with the measured results.

Optical Versus RF Free-Space Signal Transmission: A Comparison of Optical and RF Receivers Based on Noise Equivalent Power and Signal-to-Noise Ratio

To compare the power efficiency of free-space signal transmission over an optical carrier with that of signal transmission over an RF carrier, we compare the signal to noise ratio and the noise equivalent power of various optical detection schemes with that of simple antenna reception of an RF signal. We point out that for direct optical detection schemes, the noise equivalent power for optical detection is orders of magnitude larger than for RF signal detection with an antenna, with only coherent optical detection requiring similar power levels at the receiver as RF detection with an antenna and mixer, for the same available bandwidth. This is often ignored in articles in which the relative advantages of optical and RF transmission are discussed. Optical transmission mostly has advantages when very high capacity is required and where the available RF bandwidth is small.

ОБЗОР ИССЛЕДОВАНИЙ АДАПТИВНОГО ФОРМИРОВАНИЯ ДИАГРАММЫ НАПРАВЛЕННОСТИ И ЦИФРОВОЙ ОБРАБОТКИ СИГНАЛОВ

Introduction: Recently, there has been an active development of algorithms for adaptive beamforming. Such work is required in order to improve the efficiency of receiving a useful signal, especially in mobile communication systems. This article provides an overview of research on this topic. Papers devoted to the improvement of the classical least mean square algorithm, blind signal separation methods, antenna selection algorithms in MIMO systems and other topics of adaptive signal processing are presented. Practical relevance: Adaptive beamforming is a key development for modern wireless communication systems, in particular 5G. Increasing requirements that impose a limitation on the spectral bandwidth of the signal and its center frequency with limited signal power lead to the strategy of forming a narrow signal transmission beam, thereby increasing the energy efficiency of signal transmission and reducing the overhead associated with the reception of various interference. This article provides an overview of studies on this topic. The results of the analysis of works devoted to the improvement of the classical algorithm for minimizing the mean square error, blind signal separation, antenna selection algorithms in systems of several antennas, and other topics of adaptive signal processing are presented. Discussion: It is shown that the main directions of research are focused on the improvement of classical diagramming algorithms, as well as on the improvement of methods for receiving digital signals in MIMO systems. Algorithms for recognizing the type of signal modulation, an algorithm for blind separation of second-order signals, an improved algorithm for automatic gain control, an algorithm for suppressing noise-like interference, and an algorithm for estimating radiation pattern parameters were also considered.

Energy-efficient firing patterns with sparse bursts in the Chay neuron model

The energy efficiency of neural signal transmission is thought to be an important constraint in the nervous system. It is generally measured as the energy consumed per unit of information. Most of the previous studies have demonstrated this efficiency by focusing on single action potentials. However, neural information is more likely to be encoded by a spike train rather than by a single spike. To date, how the energy efficiency is dependent on patterns of spike trains is still unclear. In this study, we examined the energy efficiency of various firing patterns simulated by the Chay neuron model, including relatively high-frequency activities with massive spikes, medium-frequency activities with a moderate number of spikes, and low-frequency activities with rare spikes. Our results indicate that medium-frequency patterns are more energy efficient than both the high-frequency and low-frequency patterns. The most efficient medium-frequency pattern is a sparse burst firing (SBF) pattern because it consumes minimal energy and transmits an amount of neural information comparable to that of high-frequency patterns which consume much more energy. SBF patterns minimize energy consumption not only by producing fewer spikes than high-frequency patterns, but more importantly, also by consuming available energy sources, namely the potential energy stored in ionic concentration gradients, in a balanced way. Furthermore, with fewer spikes, the irregular spike trains of SBF patterns with short bursts and single spikes maximize the neural information that they carry, leading to higher energy efficiency. Thus, the sensory system may give priority to limiting energy costs over maximizing information to achieve greater energy efficiency.

IoT Utilized Gas-Leakage Monitoring System with Adaptive Controls Applicable to Dual Fuel Powered Naval Vessels/Ships: Development &amp; Implementation

Abstract Leakage of Liquefied Petroleum Gas and Liquified Natural Gas (LPG/LNG) produces hazardous and toxic impact on humans and other living creatures. The authors developed a system to monitor and control the gas leakage concentration. MQ-6 gas sensor is used for sensing the level of gas concentration in a closed volume. To monitor the consequences of environmental changes an IoT platform hosted by “Thingspeak” platform has been introduced. Both robust and cloud-forwarded controls have been applied to prevent uncontrolled leakage of those gases and auto-ignition. This type of system can be directly applied to the engine chamber/ fuel chamber of the modern marine vessels using dual fuel power cycle with LPG/LNG as secondary fuel-flamer. The results from the experiments clearly indicate satisfactory actuation speed and accuracy. The trials performed by the authors showed about 99% efficiency of signal transmission and actuation.

Semiconductor Plasma Antennas Formed by Laser Radiation

Efficiency of the transmission of high-frequency signals by semiconductor plasma antennas based on Ge and Si single crystals with surface nonequilibrium electron-hole plasma generated by laser diode radiation has been experimentally studied. Dependences of the amplitude of a radiated 6- to 7.5-GHz microwave signal on the laser power and size of the laser-irradiated region on the semiconductor transmitting dipole antenna are determined. It is shown that a more than tenfold increase can be achieved in the efficiency of useful signal transmission by the plasma antenna formed in Ge crystals.

Enhancing Wireless Transmission from the Body with Wearable Diffractive Patterns

Implanted medical devices often transmit wireless signals to communicate with external equipment, but the efficiency of signal transmission is limited by internal reflection at the surface of the body. This work presents an approach to greatly enhance transmission, through the design of diffractive patterns capable of converting evanescent waves on the body's surface into waves propagating into the surrounding space. When printed on clothing and worn on the body, these patterns can increase the wireless signal's strength by nearly an order of magnitude, which may pave the way for longer-lasting and more functional bioelectronics.

Synapse loss and progress of Alzheimer\u2019s disease -A network model

We present observational evidence from studies on primary cortical cultures from AD transgenic mice, APPSwe/PS1ΔE9 (APP/PS1) mice, for significant decrease in total spine density at DIV-15 and onward. This indicates reduction in potential healthy synapses and strength of connections among neurons. Based on this, a network model of neurons is developed, that explains the consequent loss of coordinated activity and transmission efficiency among neurons that manifests over time. The critical time when structural connectivity in the brain undergoes a phase-transition, from initial robustness to irreparable breakdown, is estimated from this model. We also show how the global efficiency of signal transmission in the network decreases over time. Moreover, the number of multiple paths of high efficiency decreases rapidly as the disease progresses, indicating loss of structural plasticity and inefficiency in choosing alternate paths or desired paths for any pattern of activity. Thus loss of spines caused by β-Amyloid (Aβ) peptide results in disintegration of the neuronal network over time with consequent cognitive dysfunctions in Alzheimer’s Disease (AD).

Novel hybrid action of GABA mediates inhibitory feedback in the mammalian retina.

The stream of visual information sent from photoreceptors to second-order bipolar cells is intercepted by laterally interacting horizontal cells that generate feedback to optimize and improve the efficiency of signal transmission. The mechanisms underlying the regulation of graded photoreceptor synaptic output in this nonspiking network have remained elusive. Here, we analyze with patch clamp recording the novel mechanisms by which horizontal cells control pH in the synaptic cleft to modulate photoreceptor neurotransmitter release. First, we show that mammalian horizontal cells respond to their own GABA release and that the results of this autaptic action affect cone voltage-gated Ca2+ channel (CaV channel) gating through changes in pH. As a proof-of-principle, we demonstrate that chemogenetic manipulation of horizontal cells with exogenous anion channel expression mimics GABA-mediated cone CaV channel inhibition. Activation of these GABA receptor anion channels can depolarize horizontal cells and increase cleft acidity via Na+/H+ exchanger (NHE) proton extrusion, which results in inhibition of cone CaV channels. This action is effectively counteracted when horizontal cells are sufficiently hyperpolarized by increased GABA receptor (GABAR)-mediated HCO3− efflux, alkalinizing the cleft and disinhibiting cone CaV channels. This demonstrates how hybrid actions of GABA operate in parallel to effect voltage-dependent pH changes, a novel mechanism for regulating synaptic output.