Array Elements Research Articles

RL-MUL 2.0: Multiplier Design Optimization with Parallel Deep Reinforcement Learning and Space Reduction

Multiplication is a fundamental operation in many applications, and multipliers are widely adopted in various circuits. However, optimizing multipliers is challenging due to the extensive design space. In this paper, we propose a multiplier design optimization framework based on reinforcement learning. We utilize matrix and tensor representations for the compressor tree of a multiplier, enabling seamless integration of convolutional neural networks as the agent network. The agent optimizes the multiplier structure using a Pareto-driven reward customized to balance area and delay. Furthermore, we enhance the original framework with parallel reinforcement learning and design space pruning techniques and extend its capability to optimize fused multiply-accumulate (MAC) designs. Experiments conducted on different bit widths of multipliers demonstrate that multipliers produced by our approach outperform all baseline designs in terms of area, power, and delay. The performance gain is further validated by comparing the area, power, and delay of processing element arrays using multipliers from our approach and baseline approaches.

Active Inference and Artificial Spin Ice: Control Processes and State Selection.

Theory and simulations are used to demonstrate implementation of a variational Bayes algorithm called "active inference" in interacting arrays of nanomagnetic elements. The algorithm requires stochastic elements, and a simplified model based on a magnetic artificial spin ice geometry is used to illustrate how nanomagnets can generate the required random dynamics. Examples of tracking and PID control are demonstrated and shown to be consistent with the original stochastic differential equation formulation of active inference. Interestingly, nonlinear response in the form of spikes and spike trains not predicted by the original theory can appear in the nanomagnet system for certain temperature regimes. A theoretical approach using a mean-field approximation for spin systems is proposed, which describes the transition to nonlinear response. Finally, the possibility to create simple magnetic arrays using realistic models is shown with micromagnetic simulations of a simple 17 element array of nanomagnets that include magnetic anisotropies, and exchange and dipolar interactions. Possible applications are simulated to illustrate how nanomagnetic arrays can be used as the stochastic element for feedback control of processes, investigation and control of magnetic state evolution, and as a method to optimize pulsed field magnetic switching protocols.

Nanoscale visualization of Drosophila E-cadherin ectodomain fragments and their interactions using DNA origami nanoblocks

The adhesive function of cell surface proteins can be visually assessed through direct observation; however, the underlying structures that mediate adhesion typically remain invisible at the nanoscale level. This hinders knowledge on the diversity of molecular architectures responsible for cell-cell adhesion. Drosophila E-cadherin (DE-cadherin), a classical cadherin with a unique domain structure, demonstrates adhesive function; however, it lacks a structural model that explains its adhesion mechanism. Here, we present a novel application of DNA origami technology to create a cell-free, flat environment in which full DE-cadherin ectodomains are anchored using SNAP-tags and biotin-streptavidin interactions. DNA origami was assembled into a 120 nm long block, bearing 5 or 14 biotin:streptavidin sites that were evenly spaced on one lateral face. DE-cadherin ectodomain fragments were attached via biotinylated SNAP-tags. These decorated DNA origami nanoblocks were subjected to transmission electron and high-speed atomic force microscopy, which revealed a hinge-like site that separated the membrane-distal and -proximal portions of the DE-cadherin ectodomain, suggesting a role in mechanical flexibility. We also observed interactions between DE-cadherin ectodomains via their membrane-distal portions on single DNA origami nanoblocks. We reconstituted an adhesion-like process via pairing DNA origami nanoblocks using DE-cadherin ectodomain interactions. Homophilic associations of functional DE-cadherin ectodomains between the paired DNA origami nanoblocks were visualized at the nanoscale, displaying strand-like molecular configurations, likely representing the extracellular cadherin repeats without regular arrays of structural elements. This study introduces a DNA origami-based platform for reconstituting and visualizing cadherin ectodomain interactions, with potential applications for a broader range of adhesion molecules.

A combined noise source model based on vertical coherence to quantify the proportions of two types of noise power.

With the vigorous development of maritime trade, the frequency band from 100 to 1500 Hz of shallow-sea ambient noise is not only affected by surface wind-induced noise but also the contribution of ship noise. Shallow-sea ambient noise can be described by a linear combination of surface wind-induced noise sources and ship noise sources. By using the correspondence between the real part of the vertical coherence and vertical energy flux, this work establishes a combined noise source model based on vertical coherence. A 64-element vertical array is used to measure the ocean ambient noise 103 m deep in an area of the South China Sea. Two scenarios, one dominated by surface wind-induced noise and one dominated by wind-induced noise and ship noise, are selected for investigation. By comparing the theoretical and measured values, the accuracy of the model proposed in this paper and its ability to remove the ship noise reliably are verified. This approach can be used to quantify the proportion of ship noise power in shallow-sea low-frequency environments and evaluate the contributions of wind-induced noise and ship noise at different times.

DOA estimation algorithm for non-circular signal by a large-spacing array with auxiliary element

In this paper, a direction of arrival (DOA) estimation algorithm for non-circular signal by a large-spacing uniform array with an auxiliary element has been presented. The auxiliary element is placed away from the last element of the large-spacing uniform array. The spacing between arbitrary two elements of the whole array is not limited by the half-wavelength of the signal. Firstly, two initial signal subspaces corresponding to the large-spacing uniform array and two row vectors corresponding to the auxiliary element are obtained by eigenvalue decomposition (EVD) of the correlation matrix. The two row vectors are expanded into two virtual signal subspaces by using the two initial signal subspaces. Then, the relationship between the virtual signal subspaces and the initial signal subspaces are used to form a high-dimensional signal subspace corresponding to a uniform linear array with half-wavelength spacing. Finally, DOA estimation can be got by using the estimation of signal parameters via the rotational invariance techniques (ESPRIT) algorithm. Compared with the traditional ESPRIT algorithm and non-circular ESPRIT (NC-ESPRIT) algorithm based on a conventional uniform linear array, the proposed algorithm has higher accuracy for DOA estimation and stronger robustness to the mutual coupling.

CHEMICAL SENSORS WITH MEMRISTIVE PROPERTIES: REVIEW

The article provides a brief review of literature data related to the principles of operation and parameters of currently created semiconductor heterostructures with memristive properties, in which the electrical resistance switching is caused by different physicochemical principles. The considered structures are promising from the point of view of their application in the role of discrete gas-sensitive and biosensor cells with improved operational characteristics, as well as elements of multisensory neuromorphic arrays of the “electronic nose”-like systems.

Gamma‐ray and neutron attenuation of carbon fiber/epoxy composites with carbon nanotubes and boron nitride nanoparticles for passive shielding applications in space

AbstractComposite materials have made far‐reaching changes in the space industry since they have been adopted into the structural and thermal control subsystems of space vehicles because of their several multi‐functions, including being lightweight as well as having advanced mechanical and thermal properties. The use of composites as space radiation shielding materials is also one of the most crucial applications because space radiation is a major impediment for current and future deep‐space missions. Investigation of carbon fiber composites with a diverse array of element and nanoparticle reinforcements has revealed their potential as an alternative to conventional radiation shielding materials in space. This study focused on the alleviation of gamma‐ray and neutron radiation by carbon fiber/epoxy composites incorporated with various weight ratios of carbon nanotube (CNT) and boron nitride (BN) nanoparticles. A narrow beam geometry setup was used for gamma radiation tests with a Cs‐137 gamma‐ray source, while neutron radiation experiments were conducted in a neutron howitzer with a 239Pu‐Be neutron source. Six groups of specimens, namely, pure carbon fiber/epoxy, 0.5 wt% CNT, 0.5 wt% BN, 0.5 wt% CNT + 0.5 wt% BN, 1 wt% CNT + 1 wt% BN, and 2 wt% BN, were examined against these two types of radiation. Results have indicated that the 2 wt% BN specimen showed the best attenuation properties against both gamma‐ray and neutron radiation among all tested specimens; furthermore, it was almost three times more effective against neutron radiation than against gamma‐ray radiation.Highlights Varying weight ratios of CNT and BN nanoparticles used for radiation shielding. A Cs‐137 gamma‐ray source used in narrow beam geometry. Neutron radiation studies were conducted in a 239Pu‐Be neutron howitzer. The 2 wt% BN sample showed the best attenuation against gamma‐ray and neutron radiation. It resulted in an HVL of 6.86 cm for gamma‐ray radiation and 2.13 cm for neutron radiation.

Temperature imaging by tunable diode laser absorption spectroscopy (TDLAS) with a 64-element array sensor

Temperature imaging by tunable diode laser absorption spectroscopy (TDLAS) with a 64-element array sensor

All-at-once RNA folding with 3D motif prediction framed by evolutionary information.

Structural RNAs exhibit a vast array of recurrent short 3D elements involving non-Watson-Crick interactions that help arrange canonical double helices into tertiary structures. We present CaCoFold-R3D, a probabilistic grammar that predicts these RNA 3D motifs (also termed modules) jointly with RNA secondary structure over a sequence or alignment. CaCoFold-R3D uses evolutionary information present in an RNA alignment to reliably identify canonical helices (including pseudoknots) by covariation. We further introduce the R3D grammars, which also exploit helix covariation that constrains the positioning of the mostly non-covarying RNA 3D motifs. Our method runs predictions over an almost-exhaustive list of over fifty known RNA motifs (everything). Motifs can appear in any non-helical loop region (including 3-way, 4-way and higher junctions) (everywhere). All structural motifs as well as the canonical helices are arranged into one single structure predicted by one single joint probabilistic grammar (all-at-once). Our results demonstrate that CaCoFold-R3D is a valid alternative for predicting the all-residue interactions present in a RNA 3D structure. Furthermore, CaCoFold-R3D is fast and easily customizable for novel motif discovery.

Pulse splitting technique for low sidelobe time-modulated antenna array synthesis with harmonic suppression

Abstract In this paper, pulse splitting approach is proposed to simultaneously reduce the sidelobe level (SLL) of fundamental signal and maximum sideband levels (SBLs) of harmonic signals for time-modulated linear array (TMLA). This is achieved by controlling only the periodic switching time sequence of each element of the TMLA. In pulse splitting, the on–off switching sequence of each radiating element is characterized by multiple rectangular sub-pulses within the modulation period which increase the degrees of freedom in order to better synthesize the desired fundamental pattern with simultaneous suppression of harmonic or sideband radiation. A genetic algorithm is employed to optimize the switch-on and switch-off instants of each sub-pulse for each element for 16-element uniform amplitude, phase, and space linear antenna array. The simulation results reveal that the proposed method can achieve the desired patterns with very low SLL and SBLs compared with previous published results.

Light-Emitting Diode Array with Optical Linear Detector Enables High-Throughput Differential Single-Cell Dielectrophoretic Analysis.

This paper presents a lens-free imaging approach utilizing an array of light sources, capable of measuring the dielectric properties of many particles simultaneously. This method employs coplanar electrodes to induce velocity changes in flowing particles through dielectrophoretic forces, allowing the inference of individual particle properties from differential velocity changes. Both positive and negative forces are detectable. The light source utilized in this system is composed of LEDs with a wavelength of 470 nm, while detection is performed using a 256-element optical array detector. Measurements with 10 μm polystyrene beads demonstrate this method can resolve changes equivalent to a Clausius-Mossotti factor of 0.18. Simulations in this work, using values from the literature, predict that Clausius-Mossotti factor differences of 0.18 are sufficient to differentiate viable from nonviable cells and cancerous from multidrug-resistant cancerous cells. We demonstrate that for Chinese hamster ovary (CHO) cells, the method can collect a dielectric response spectrum for a large number of cells in several minutes. We demonstrate that for CHO cells, Clausius-Mossotti factor differences of 0.18 can be discriminated. Due to its simple detection apparatus and the utilization of high-throughput, wide, clog-resistant channels, this method holds promise for a wide range of applications.

A Broadband and Wide-Scanning Dual-Polarized Dipole Array with Low Profile

This study presents a novel methodology for designing a planar broadband wide-scanning dual-polarized array using tightly-coupled dipoles and wide-angle impedance matching. By etching the S-shaped gaps between the dipoles and incorporating shorting vias with defected ground structures, we demonstrated that all radiation elements can be arranged on a single-layer substrate. Additionally, we introduced a thin printed circuit board (PCB) layer with two-dimensional periodic structures for impedance matching at wide scan angles. Leveraging high permittivity and constrained electromagnetic waves, we realized zero-scan blindness within this band. The aperture consisted of only two PCB layers, with a total profile of approximately 0.091λlow, where λlow represented the free-space wavelength at 6 GHz. A 3 × 4 dual-polarized array was fabricated and measured to validate the proposed approach. The measured active voltage standing wave ratio for one embedded array element surpassed 2.2 over 6–18 GHz. By enabling the orthogonal dipoles at the edge of the array to be mutually coupled using an additional metal patch, the active S11 for the edge cells exceeded −8.8 dB over 6.9–18 GHz. The measured patterns were in good agreement with simulations over 6–18 GHz, with the array exhibiting good radiation performance over ±60° in the E- and H-planes.

One Receptor Show: Evaluation of Feature Extraction Methods for a Single Gas Sensor Based on α-Tocopherol-Substituted Zinc Phthalocyanine.

A consistent part of gas sensor research activities aims to improve sensing performances by synthesizing new sensing materials, improving the selection of elements in arrays, and optimizing the feature extraction and classification algorithms. This paper combines most of these aspects to confer selectivity to a low-selectivity sensor by using feature extraction algorithms applied to the sensor response kinetics. Several algorithms were employed to represent the kinetic behavior of the sensor response during the adsorption and desorption phases. In detail, we utilized fitting functions, dynamic descriptors, and a mirrored fast Fourier transform (FFT) to extrapolate information from the desorption and adsorption phases. As sensitive material, we synthesized as a receptor a novel Zn(II) phthalocyanine derivative bearing long aliphatic chains, namely, 4-[2,5,7,8-tetramethyl-2-(4,8,12-trimethyl-tridecyl)-chroman-6-yloxy] units that allow good solubilization of the complex in most of the solvents tested and confer a large set of sites to potentially interact with volatile compound (VC) analytes by different portions of the molecular skeleton. After deposition onto a quartz crystal microbalance (QMB) transducer, this single sensor has been tested to recognize five VCs as chemical probes of different chemical families. Remarkably, the results disclose that responses at equilibrium are mainly correlated with nonspecific interactions, while the kinetic parameters are more correlated with stronger and more specific interactions. Finally, the desorption phases bear a higher information content about the chemical identities of the compounds. Eventually, features extracted by a modified version of the FFT obtained the highest clustering (principal component analysis) and classification performances (95% classification accuracy with linear discriminant analysis), suggesting the possibility of developing virtual electronic noses based on a single sensor and a minimal set of descriptors.

A 2x2 Mimo Microstrip Patch Antenna Design For X-Band Applications Using Inverted Array Orientation Approach

Objective: The main goal of this research is to design and simulate a unique 2x2 multiple-input and multiple-output, (MIMO) Rectangular Microstrip Patch antenna (RMPA) using an inverted array orientation approach with keen interest in improving the radiation efficiency and performance characteristics of the X- band based antenna. Theoretical Framework: This work integrates principles from Electromagnetic theory, communication theory, and basic Microstrip antenna design concepts. The framework is built upon crucial design goals such as radiation efficiency, reliability, element orientation and compactness of the antenna elements. Method: This research adopted a design and simulation approach. All the antenna design modules and analysis were conducted using MATLAB R2023b simulator. Firstly, this work modelled and designed a unique single-element RMPA after iterations and optimisations of the antenna parameters to achieve enhanced performance. The achieved single element was used to model a 2x2 MIMO antenna with specified element spacing. The design applied an inverted element array orientation and streamlined feed trace mechanism to achieve a high gain and enhanced radiation efficiency. Results and Discussion: The unique antenna design recorded a return loss of -15.2 dB, directivity of 7.33 dB, bandwidth of 484.8 MHz, gain of 7.16 dB, VSWR of 1.41, and radiation efficiency of 96.2%. Further analysis on the designed MIMO antenna to ascertain the mutual coupling effect showed that Envelope Correlation Coefficient (ECC) values remained below 0.2 within the 10 GHz frequency band, representing good diversity and significantly reducing the mutual coupling effect between array elements. The Diversity Gain (DG) of 9.87 and 9.84 dB were obtained. These values are near the optimal value of 10 dB, which is diversity for MIMO applications. Research Implications: The findings show the viability of the proposed design based on the performance metrics considered when compared to the previously designed Microstrip Patch Antennas (MPA). Thus, the designed MIMO antenna is suggested for use in embedded wireless communication devices within 8-12 GHz frequency bands for X-band applications such as radar systems and WiMAX. Originality/Value: This study presents an innovative approach to improving the radiation efficiency of a designed 2x2 MIMO antenna. The work showed that enhancement of the radiation efficiency has a direct effect on the mutual coupling, which this work applied inverted orientation and streamlined feed trace method to minimise.

An electromagnetic ultrasonic synthetic aperture focusing imaging method based on wave packet decomposition optimisation to eliminate artefacts

ABSTRACT Electromagnetic acoustic transducer testing technology (EMAT) has the advantages of non-contact, no coupling agent, and easy excitation of different waveforms. It has advantages in applications such as high-temperature online detection. Synthetic aperture focusing technique (SAFT) can use a single ultrasonic array element to achieve high-resolution imaging, providing a new idea for electromagnetic ultrasonic imaging detection. The efficiency of electromagnetic acoustic transducer is low and the signal components are complex. How to eliminate imaging artefacts is a problem that needs to be studied. This paper analyzes the sound field distribution of common types of electromagnetic ultrasound transducers and the causes of noise wave packet generation, and proposes a wave packet decomposition technology based on the zero-mean normalised cross-correlation criterion. Decompose the defect echo signal, optimise the waveform, and increase the number of signals through interpolation algorithms. Experiments show that the proposed method can effectively eliminate artefacts and improve the quality of electromagnetic ultrasonic synthetic aperture focusing imaging.

Broadband Millimeter-Wave Front-End Module Design Considerations in FD-SOI CMOS vs. GaN HEMTs

Millimeter-wave (mm-Wave) phased array systems need to meet the transmitter (Tx) equivalent isotropic radiated power (EIRP) requirement, and that depends mainly on the design of two key sub-components: (1) the antenna array and (2) the Tx power amplifier (PA) in the front-end-modules (FEMs). Simulations using an electromagnetic (EM) solver carried out in Cadence AWR with AXIEM suggest that for two uniform square patch antenna arrays at 24 GHz, the 4 element array has ~6 dB lower antenna gain and twice the half power beam width (HPBW) compared to the 16 element array. We also present measurements and post-layout parasitic-extracted (PEX) EM simulation data taken on two broadband mm-Wave PAs designed in our lab that cover the key portions of the fifth-generation (5G) FR2-band (i.e., 24.25–52.6 GHz) that lies between the super-high-frequency (SHF, i.e., 3–30 GHz) band and the extremely-high-frequency (EHF, i.e., 30–300 GHz) band: one designed in a 22 nm fully depleted silicon on insulator (FD-SOI) CMOS process, and the other in an advanced 40 nm Gallium Nitride (GaN) high-electron-mobility transistor (HEMT) process. The FD-SOI PA achieves saturated output power (POUT,SAT) of ~14 dBm and peak power-added efficiency (PAE) of ~20% with ~14 dB of gain and 3 dB bandwidth (BW) from ~19.1 to 46.5 GHz in measurement, while the GaN PA achieves measured POUT,SAT of ~24 dBm and peak PAE of ~20% with ~20 dB gain and 3 dB BW from ~19.9 to 35.2 GHz. The PAs’ measured data are in good agreement with the PEX EM simulated data, and 3rd Watt-level GaN PA design data are also presented, but with simulated PEX EM data only. Assuming each antenna element will be driven by one FEM and each phased array targets the same 65 dBm EIRP, millimeter wave (mm-Wave) antenna arrays using the Watt-level GaN PAs and FEMs are expected to achieve roughly 2× wider HPBW with 4× reduction in the array size compared with the arrays using Si FEMs, which shall alleviate the thorny mm-Wave line-of-sight (LOS)-blocking problems significantly.

An interpretable RNA foundation model for exploring functional RNA motifs in plants.

The complex 'language' of plant RNA encodes a vast array of biological regulatory elements that orchestrate crucial aspects of plant growth, development and adaptation to environmental stresses. Recent advancements in foundation models (FMs) have demonstrated their unprecedented potential to decipher complex 'language' in biology. In this study, we introduced PlantRNA-FM, a high-performance and interpretable RNA FM specifically designed for plants. PlantRNA-FM was pretrained on an extensive dataset, integrating RNA sequences and RNA structure information from 1,124 distinct plant species. PlantRNA-FM exhibits superior performance in plant-specific downstream tasks. PlantRNA-FM achieves an F1 score of 0.974 for genic region annotation, whereas the current best-performing model achieves 0.639. Our PlantRNA-FM is empowered by our interpretable framework that facilitates the identification of biologically functional RNA sequence and structure motifs, including both RNA secondary and tertiary structure motifs across transcriptomes. Through experimental validations, we revealed translation-associated RNA motifs in plants. Our PlantRNA-FM also highlighted the importance of the position information of these functional RNA motifs in genic regions. Taken together, our PlantRNA-FM facilitates the exploration of functional RNA motifs across the complexity of transcriptomes, empowering plant scientists with capabilities for programming RNA codes in plants.

A sidelobe level control algorithm for wide-beam power gain pattern synthesis via array antenna

The paper tries to maximize the minimum power gain in a wide-beam mainlobe with a controllable peak sidelobe level (PSLL) by solving the power gain pattern synthesis (PGPS) problem. Since the PGPS problem is nonconvex, it cannot be solved effectively in polynomial time. In this paper, the nonconvex PGPS problem is simplified by converting it into two nonconvex subproblems. The first subproblem's solution space is divided into a finite set of smaller spaces in which the solution has a closed-form, resulting in the subproblem being pseudo-analytically solvable. The second subproblem's solution can be rapidly obtained with a bisection searching strategy. In such a way, the original problem can be solved effectively by iteratively solving these two subproblems. Another advantage of the proposed algorithm is that its convergence is theoretically guaranteed and the PSLL is strictly controllable. Numerical examples with both isotropic element pattern (IEP) array and active element pattern (AEP) array are simulated to validate the effectiveness and superiority of the proposed algorithm by comparing it with the existing algorithms.

Tilt noise extraction method based on fourier transform and fitting of 2D images

Tilt control is necessary for high-power coherent beam combining systems with large array elements. A tilt noise extraction method based on 2D images has been developed, and the analysis of abnormal situations has been executed. The method achieves high accuracy solution of tilt after two-step operation of Fourier transform and fitting of interference fringes at the detecting module, and then feeds back the compensated amount to the controlling module to achieve tilt control. Monte Carlo simulation is used to solve the control accuracy of this method. The tilt residuals of the method were calculated at various intrinsic shears and data lengths. Results of the effect of the magnitude of the intrinsic shear and the amount of data on the tilt residuals verified the accuracy and stability of the method.

Innovative Approaches to Beam Forming Antenna Array Systems with Adaptive Partial Update NLMS Algorithms

Improvements in interference cancellation, energy economy, spectrum efficiency, and system security are among the most pressing needs for today's wireless networks. One effective technique for this is the use of a Beamforming Array Antennas (BAA). However, the complexity of the Beamforming (BF) network, the long convergence time, and the large number of adjustable weight coefficients, all work against full band BAA. The key innovation and contribution of this research was to use Partial Update (PU) instead of full band adaptive algorithms, as no previous attempt had been made to do so. A subset of the array's elements, rather than all of them, will be connected to by PU methods. This allows the system to reduce the number of active antennas across all cells while maintaining high efficiency, and low cost. In this research, a new architectural model was proposed that makes use of PU adaptive algorithms, to reduce the required number of phase shifters (PSs), and hence base station antennas. For the most part, we will be discussing PU Normalized Least Mean Square (PU NLMS) algorithms like M-max NLMS, Periodic-NLMS, and Stochastic-NLMS. Using a Uniform Linear Array (ULA) Antennas in a simulation environment, we find that the, in terms of Mean Square Error (MSE), convergence rate, and steady-state error, it is evident that all PU NLMS algorithms (with the exception of Periodic-NLMS) had performed close, and approximately equivalent performance to the full band NLMS algorithms. In other hands, these PU algorithms maintain the radiation pattern with as little change from the original (distortion-free) as possible and symmetrical of the array, while. fewer elements are needed to produce the same amount of radiation. Reducing the number of required coefficients N to M (M = 5; M: Number of coefficients to be update per iteration) compared to the full update method (N = 8), to obtain the Reduction ratio 38%.