Miracle-dz/UniFAR-FTUs huggingface dataset:
Fast Signal Completion Algorithm with Cyclic Convolutional Smoothing

Recently, signal completion methods using delay-embedding transforms (DT) have been actively studied. Since the DT is an operation to transform a signal into a Hankel matrix, the high computational cost associated with the increase in data size is an issue. In this study, we consider modeling smooth signals based on inverse delay-embedding instead of delay-embedding. We propose a new algorithm that incorporates the properties of the delay-embedding-based methods while reducing the computational cost. The proposed algorithm takes advantage of the inverse delay-embedding being a cyclic convolution, and the computational complexity can be reduced to $\mathcal{O}(NlogN)$ by transforming the optimization problem to Fourier space. Numerical experiments with typical signals and audio data show the effectiveness of the proposed algorithm in signal declipping and completion problems.
EEG-based Auditory Attention Detection with Estimated Speech Sources Separated from an Ideal-binary-masking Process

Previous studies showed that auditory attention can be decoded from the corresponding electroencephalography (EEG) signals. Most existing EEG-based auditory attention detection (AAD) methods identify target speech in the competing-speaker scenes by comparing the correlation coefficients between the speech envelope of each clean stream and the speech envelope reconstructed from the EEG signals. The usage of separate speech streams limits the actualization of EEG-based AAD in the realistic environments. The current study aimed to develop and assess an EEG-based AAD method using the estimated speech sources separated from an ideal-binary-masking (IBM) process. Specially, the IBM-based speech processing method was first implemented to separate the speech sources in the competing-speaker scenes. Then the estimated IBM-processed speech sources were used to establish the AAD model and extract the target speech stream. Experimental results demonstrated that the AAD accuracies computed with the estimated IBM-processed speech sources were comparable to those with original clean speech sources over a range of signal-to-masker ratios. These findings indicate that the estimated IBM-processed speech sources provide necessary and sufficient information for the EEG-based AAD methods, which facilitate the extraction of attention-driven target speech streams in noisy environments.
Contactless Transfer Learning Based Apnea Detection System for Wi-Fi CSI Networks

Sleep apnea syndrome is a common sleep disorder that can lead to a variety of diseases. The traditional diagnostic method, polysomnography (PSG), is time-consuming, expensive, and inconvenient for patients. In this paper, we proposed the transfer learning based apnea detection (TLAD) system as a non-contact based method utilizing the channel state information (CSI) from commercial Wi-Fi devices. In order to reduce the overhead of collecting CSI data and improving efficiency during training process, the transfer learning technique is applied to establish pre-trained model by utilizing open source contact-based thoracic movement data. Moreover, existing research works detect apnea based on breathing pauses and shallow breathing periods, which are not effective to identify complex apnea characteristics. This potential drawback is overcome in proposed TLAD system since both CSI amplitude and frequency features are extracted for apnea classification. Our experimental results showed that the TLAD system achieves an F1-score of 90.1, which is superior to other existing methods.
Head Model Simplification Methods Based on Validity Estimate for Transcranial Magnetic Stimulation

The distribution of electric field (E-field) induced by transcranial magnetic stimulation (TMS) can usually obtained by numerical calculation. To improve calculation efficiency, various types of simplified head models were used in previous studies, but no exact research on the influence of different simplification methods on calculation results has been put forward yet. In this article, 56 numerical human head models (including 7 original models) divided into 7 groups were constructed first, then 3 types stimulus coils were performed to get numerical calculation results. The 5th-percentitle, the 10th-percentitle, the 25th-percentitle, the 50th-percentitle, the 75th-percentitle, the 90th-percentitle, the 95th-percentitle and the 99th-percentitle (peak field value) of E-field in gray matter layer of original models and corresponding simplified ones were used to estimate the validity of simplification methods quantitatively. As for simplified model 2, the maximum absolute relative error of percentiles was 6.97%, which was smaller than absolute relative error of other simplified models and meant the simplification method of incorporating the scalp layer into skull layer was applicable to model I~VII. These works could be technical references for further studies which need to use simplified head model in numerical calculation for TMS.
Reed-Muller Sequence-Based Unsourced Random Access over Multipath Fading Channels

An unsourced random access scheme using the second-order Reed-Muller (RM) sequences is proposed. Each of the active devices maps its message to an RM sequence and randomly selects a single subcarrier to transmit through a multipath fading channel. In a receiver, after OFDM demodulation, at each subcarrier the list of corresponding messages is blindly decoded by iterative RM decoding. Simulations show that the proposed systems provide low block error rates over multipath fading channels.
A V-band Differential Colpitts Push-Push VCO in 130 nm SiGe BiCMOS

A V-band push-push VCO operating from 68.5 GHz to 73 GHz is presented. This design introduces a capacitor at the common-base node, which enhances odd mode oscillation and maximizes the common-mode impedance of the differential oscillator. At the output end, a transformer is used to decouple both fundamental and 2nd harmonic frequency signals. The desired 2nd harmonic frequency signal is delivered to the output, whereas the fundamental frequency signal can be fed back for phase-detection in a phase-locked loop. The implemented VCO delivers a peak output power of 1.2 dBm at 72.5 GHz, and achieves a phase noise of -103 dBc/Hz at 1-MHz offset, respectively. The circuit is designed on a 130 nm SiGe BiCMOS technology with $f_{T}/f_{max}$ of 200/300 GHz. The total power consumption of the signal source is 50 mW with a supply voltage of 1.8 V.
Analysis and Evolution of Airport Network of India

Air transportation network (ATN) is the most important facet of every nation's infrastructure for its economic development. This study examined the airport network of India (ANI) in order to have a better understanding of its characteristics. ANI consists of domestic civil aviation infrastructure of India. According to the present analysis, directed unweighted ANI, preserves the topological properties of being scale-free and a small world network. Compared to earlier studies, ANI have evolved in terms of both structural (airport, air route) and air traffic. Directed weighted ANI with edge weight of flight frequency per week provides information on several network properties like airports with high incoming flights, shortest paths between any two airports, average number of flights need to change by a passenger and airports in ANI which is highly connected. To the end, the airports with high in-degree and betweenness centrality and evaluation of ANI over the last one decade has been shown.
Rapid Analysis of Conformal Antenna Arrays via Vector Spherical Harmonics Translation

The pattern of conformal antenna array cannot be expressed as the product of array factor and element pattern since the conformal array usually has non-uniformly spaced elements and different element orientations. In this study, a new method is proposed for the rapid analysis of conformal antenna arrays consists of the identical antenna element. The method manipulates the antenna element pattern and the synthesized pattern in vector spherical harmonics domain, achieved computation advantage compared with the existing approach. Finally, an example study is provided that examines the proposed method vs a reference full-wave simulation result.
A Double-Layer Wideband Transmitarray Antenna with Compensation Elements

A double-layer wideband transmitarray antenna with small compensation elements is proposed. The double-layer transmitarray antenna consists of 441 standard elements and 128 small elements. Standard elements have two freedom degrees, which can achieve a 360° phase shift range. And small elements placed at the intersection of the four standard elements is able to generate an approximate 90° phase shift range. The simulation results show that the phase shift curve of the small unit is very flat with wide bandwidth. Therefore, the addition of small elements can not only increase the gain but also increase the bandwidth. The array is designed, manufactured and testing. The experimental data is in good agreement with the simulation. The proposed transmitarray achieves a gain of 29.5 dB at 34 GHz, with an aperture efficiency of 41% and 1dB gain bandwidth of 10.3% (32.1GHz-35.6GHz). The small elements can also be added to other similar lens antenna to enhance the gain and bandwidth.
IoT Based I-V and P-V Curve Analyzer system for small PV panels PART I

This paper presents an IoT Based I-V and P-V analyzer for Photovoltaic panel (PV) power up to 30W and PV open circuit voltage up to 22V. The ESP32 microcontroller generates Pulse Width Modulation (PWM) signal to the power electronic circuit and takes sample of PV’s voltage and current 82 samples to calculate I-V and P-V curve. The processed data then transmitted to the cloud server via MQTT protocol for display and further analysis. A PSIM simulation analysis is also performed to predict the analyzer operational performance in various light radiation intensities as well as PV operational temperatures.
Application of Deep Learning-based Single-channel Speech Enhancement for Frequency-modulation Transmitted Speech

There are three main interferences in the FM signal trans-mission process-Multipath effect, Doppler effect, and White noise. These interferences have significant influences on speech. We proposed a method that uses a masking or mapping approach for single-channel speech enhancement in wireless communication. Since the method improves speech equality by focusing on three interferences simultaneously, it is simpler in comparison to conventional methods. Experiments are conducted on the dataset, which is simulated by ourselves. Because the PESQ and STOI need reference targets, it is hard to evaluate the performance using real-world data. So we only give the spectral comparison of the real data enhancement results. Simulation results show excellent speech enhancement performance on the unprocessed mixture and significantly improve speech quality on the actual collected data. It verifies the feasibility of deep learning on this kind of task. Future studies will be made to improve the real-time performance and compress the number of network parameters.
Bandwidth-enhanced Parametric Spectro-Temporal Analyzer with Pulse-Picking Modulator

This paper focuses on ultrafast single-shot spectrum characterization with MHz frame rate. A parametric spectro-temporal analyzer (PASTA) has been proposed as a strong candidate to implement the spectrum analysis. However, the relatively complex system and limited measurement bandwidth have hindered its further practical applications. In this work, a compact PASTA system is demonstrated to have 44-pm spectral resolution and −30 dBm detection sensitivity. Besides, the PASTA system is first combined with the pulse-picking technology so that the pump repetition rate is decreased and the measurement bandwidth is enhanced to 40 nm. Our work presents a practical and feasible approach to extending the PASTA scope to more practical scenarios.
Lithium-Niobate-Based Frequency-Agile Integrated Lasers

We demonstrate narrow-linewidth ultrafast tunable integrated lasers based on heterogeneously integrated thin-film lithium niobate on ultra-low loss silicon nitride integrated photonic circuits. Using self-injection locking of a hybrid microresonator, we achieve a tuning speed of > 10 peta-Hertz-per-second. We also perform FMCW LiDAR ranging experiments.
Influences of Rotor Design on Air-Gap Field Modulation Effect in Spoke-Type Permanent Magnet Machine for Traction Applications

This paper investigates the influences of the rotor design on air-gap field modulation (AGFM) theory in spoketype permanent magnet (STPM) machines for traction applications. Due to flux-concentrated effect, STPM machines exhibit abundant air-gap field density harmonics and relatively high torque density. The Maxwell stress tensor (MST) method is adopted to identify and quantify the torque contributions of the various air-gap field harmonics in STPM machines. It reveals a fact that, except the main-order working harmonic is responsible for average torque generation, abundant modulated air-gap field harmonics contribute a non-negligible torque component. Besides, the influences of rotor open-slotting and PM arrangements on AGFM effects in STPM machines are evaluated and compared by finite element (FE) analysis, which identifies that the rotor open-slotting and PM arrangement designs show a more conspicuous effects on their torque components and AGFM effect.
2 × 2 Dual-Polarized Phased Array Testbench for 5G NR Communication and Video Transmission

This paper presents a $2 \times 2$ dual-polarized phased array testbench for fifth-generation (5G) communication system and video transmission. The transceiver chip is integrated with $2 \times2$ dual-polarized antenna array on the printed circuit board (PCB). The antenna array has rotated feed design with more than 22 dB cross-polarization rejection at broadside. The antenna element can achieve a -10 dB impendence bandwidth of 3.25 GHz (24.25-27.5 GHz) and the array presents a measured effective isotropic radiated power (EIRP) at P1dB of 29 dBm and scans $\pm 30^{\circ}$ in azimuth at 26 GHz. For validating its performance for 5G applications, dual-polarized communication link of 5G new radio (NR) signal of 400 MHz using two phased arrays is demonstrated. The error vector magnitude (EVM) degraded less than 0.1 % for dual-polarization operation compared to the single-polarization one. Also, the 1080p video transmission is validated by employing two phased arrays.
Optimal Level Number and Performance Evaluation of Si/GaN Multi-Level Flying Capacitor Inverter for Variable Speed Drive Systems

This paper analyzes the optimal number of voltage levels concerning power density for a motor-integrated Multi-Level Flying Capacitor inverter (ML FCi) with 800 V DC-link driving a 7.5 kW Permanent Magnet Synchronous Motor (PMSM). The analysis is performed for an ML FCi, as it enables high efficiency and power density required for motor integration on the one hand and decreases the output filter volume with increasing output voltage level numbers N on the other hand. General scaling laws of the ML FCi are derived analytically and a Pareto optimization based on real hardware dimensions is performed to determine which number of levels is optimal in terms of power density and efficiency and which system performance is achieved for employing Si or GaN power transistors.
An Identification Recognition Method Based on the Optimization Mechanism of Emotional EEG Module

With the rapid development of informati on society, people's demand for personal privacy a nd property protection has become stronger and st ronger. At present, the traditional biometric techno logy has been difficult to meet the needs of social de velopment. Electroencephalography (EEG), as a un ique biometric feature of individuals, has received wide attention from a large number of researchers. In order to solve the problems of difficult to apply in practice and low recognition accuracy due to the induction of specific situations and differences in i ndividual characteristics in EEG data acquisition, a PSO-Attention-RNN (PARNN) recognition mode 1 is proposed in this paper. Firstly, the energy entro py of five rhythms, a-wave, ß-wave, δ-wave, θ-wave and γ-wave, in EEG signals are extracted as featur e vectors by using wavelet packet transform. These features are then input into the PARNN optimized recognition model, and the EEG temporal frequen cy bands corresponding to different emotional mod ules are filtered using particle swarm optimization (PSO), which can lead to the highest recognition ac curacy for the subjects. The whole process was vali dated in a self-collected emotional EEG database. T he results show that the average recognition accura cy of the algorithm in this paper can reach 90.99%, and the recognition accuracy of the positive emotio n module reaches 93.72%.
Misalignment-Robust Codebook-Based Beamforming for OAM Mode Multiplexing Systems

In this paper, we present an algorithm to construct a misalignment-robust beamforming (BF) codebook for orbital angular momentum mode multiplexing (OAM-MM) systems. The BF codebook is constructed for a given set of antenna misalignment (AM) parameters, i.e., the AM type, rotation angles, and displacement values. We use the sorted QR-decomposition of the augmented misaligned channel matrix to design a BF codebook that is applied to received signals using phase shifters only. Subsequently, by employing the successive interference cancellation (SIC), the transmitted symbols corresponding to each OAM mode are estimated. The combination of codebook-based BF in the analog domain and the SIC in the digital domain offers an effective strategy to solve the AM problem without sacrificing the computational savings associated with the application of OAM-MM. Simulation results confirm that by adopting the proposed approach, the sum-rate of the misaligned OAM-MM system approaches the theoretical upper bound.
Spin transfer induced coherent microwave emission with large power from nanoscale MgO tunnel junctions

In low resistance-area product MgO magnetic tunnel junction nanopillars, we observe high integrated power (up to 43nW), narrow linewidth (down to 10MHz), spin transfer induced microwave emission at frequencies up to 14GHz due to precession of the free layer magnetization at room temperature. Although all devices were fabricated on the same wafer, they present bimodal transport and precessional characteristics. The devices in which the narrowest linewidths were observed exhibited low resistance and tunneling magnetoresistance (30%), while maintaining large integrated power.
Online Inductance Identification of PMSM Based on High Frequency Signal Injection into Virtual Axis

The voltage equation-based method is the most commonly applied inductance identification method. However, the effectiveness of this method is affected by the parameter coupling and the rank deficient. To solve this problem, an online inductance identification method is proposed based on the virtual axis high-frequency (HF) sinusoidal voltage signal injection strategy. According to the virtual axis HF equivalent impedance model which includes the position information between the virtual axis and the dq axes, the dq-axis inductances can be calculated by extracting the HF signal of the virtual axis. The proposed method is able to make sure that the identified parameters decouples from other motor parameters and operating conditions and the method is immune to sensorless control position error. The dq-axis inductance can be identified without rank deficient at full operation conditions, especially at low current and speed condition. The proposed method is validated on a 2. 2kW PMSM drive.
A Model Predictive Current Control Method based on Boundary Restriction for Medium-speed Maglev Train

In this paper, a model predictive current control method based on boundary restriction (BR-MPCC) is proposed for the medium-speed maglev train. Compared with the traditional switching frequency decreasing method based on the cost function (CF-MPCC), the proposed novel method is free from weights and without changing the cost function itself. Simulation results show that the BR-MPCC scheme reduces the maximum switching frequency more effectively than the traditional CF-MPCC scheme with a similar current distortion.
Nondestructive detection and imaging of trace chemicals with high-chemical specificity using single-beam coherent anti-stokes Raman scattering in a standoff configuration

The excellent chemical identification ability of Raman based spectroscopy provides a versatile and widely applicable method to identify hazards within a complex chemical environment. However, the small spontaneous Raman scattering cross section can limit standoff detection of trace quantities. Coherent anti-Stokes Raman scattering provides the same chemical specificity, but with the potential for much greater signal due to coherent addition in the non-linear spectroscopy. Utilizing CARS, we have demonstrated μg/cm2 level detection of an explosive simulant using a single laser producing less than 8mW of laser power in the near IR. This detection level was achieved on a simulant present as only a small part within a polymer mixture. In addition, we present standoff chemical images of trace compounds within a complex chemical environment, which effectively demonstrate the unique capabilities of the method. Further, the temporal pulse shape can be tailored to excite specific Raman transitions, adding versatility to this method.
Adoption of Digital Technologies for Sustainable Supply Chain_ A systematic literature review

Digital technologies has gained importance and impact almost every aspect of supply chain processes especially sustainable aspects (Triple Bottom Line perspective). However integrating and adopting DT to enhance sustainability in Supply Chains is a complex process.In this context, this study will first provide an overview of Digital Technologies adoption in Supply Chain and analyze scientific researches on SC in the field of sustainability and digitalization, then underline Challenges and Barriers and highlights their impact on Sustainability aspect.
New Derivation of the Vacuum Breakdown Equation Relating Breakdown Voltage and Electrode Separation

An analysis of the published measurements of breakdown voltage for various gap lengths for uniform and approximately uniform fields shows that the results may be represented by the breakdown equation V = Cxα and that the values of α lie in the range 0.1 to 1.1 with a mode of 0.7. A theory is developed which leads both to a breakdown equation of the same form and to a general expression to account for the range of values of α. This expression is confirmed for gaps up to 0.075 cm by direct experiment. The development is based on the postulate that an electron beam is emitted from the cathode, diverges, and bombards the anode to cause breakdown when a critical power flux is reached. The factor C is shown to include the critical power flux and to be related to both field and electrode separation. In support of the theory, the radii of craters produced on the anode are measured and shown to be related to the radius of an electron beam at the anode. Calculation shows the current carried by the beam to be of the.