Miracle-dz/UniFAR-FTUs huggingface dataset:
VECROsim: A Versatile Metric-oriented Microservice Fault Simulation System (Tools and Artifact Track)

Automated fault diagnosis of microservice systems has been a hot topic in recent years. As most incidents in real commercial cloud systems are not publicly available, we have witnessed researchers putting considerable effort into developing various experimental systems. However, previous tools cannot quickly refactor their functionality, scale the architecture, and customize fault characteristics. Given this, we develop VECROsim, a versatile metric-oriented microservice fault simulation system, and release the VECROsim benchmark dataset. VECROsim works delicately as a highly-customizable toolkit to generate abnormal performance metrics datasets of microservice systems on demand and automatically. Validation of representative services from the benchmark dataset confirms the capability of VECROsim to generate realistic performance metrics for diverse real-world systems. Our case studies on root cause analysis and dynamic correlation discovery demonstrated the superiority of VECROsim. We also witnessed that the VECROsim dataset brings new research challenges to state-of-the-art fault diagnosis schemes. VECROsim concretely supports microservice developers from the industry, as well as academic researchers working on fault diagnosis or broader research topics in many ways.
Interferometrically Coupled Reconfigurable Racetrack Resonator on Lithium Niobate-on-Insulator platform

We exploit a thermo-optically tuned interferometric coupling scheme to relax fabrication tolerances on coupling segments of microresonators in lithium niobate-on-insulator. We achieve extinction ratios up to 34 dB and show tuning of resonance bandwidth between 15 and 45 pm while maintaining extinction above 15 dB.
New Design of Antenna Array for Bluetooth Direction Finding

Bluetooth Low Energy (BLE) has become very common for tracking applications in homes, stadiums, malls, and hospitals over the last decade. With the outbreak of COVID, the technology was widely used for local tracking of the virus spread [1]. However, despite broad interest in using BLE as a tracker, the primary method is based on Received Signal Strength Indication (RSSI) measurements. On the other hand, the previous studies have demonstrated that this method is prone to multi-path and is inaccurate. With the introduction of BLE Direction Finding a shift in localization method has occurred. With the introduction of BEL direction finding, indoor tracking has come closer to its ultimate goal of asset tracking and positioning in crowded indoor environments. In this paper we present a new fast switching antenna array specifically designed for BLE direction finding. Using our newly designed antenna array and switch, we reached to accuracy of approximately 5° degrees.
Real-Time GICP: Direct LiDAR SLAM for CPU Environment

As a core part in modern Robotics research, Simultaneous Localization and Mapping (SLAM) is widely used in different kinds of autonomous robots, such as autonomous vehicles. Existing direct methods and feature-based methods in LiDAR-SLAM still have different limitations. In this paper, we propose a lightweight, robust and accurate LiDAR-SLAM framework named Real-Time GICP, which contains improved GICP method as front-end and Scan-Context loop detection to construct pose graph optimization. Experimental results show that Real-Time GICP can achieve state-of-the-art accuracy and superior computational efficiency comparing with other open-source GICP methods. Our method can achieve around 50 Hz for 64 rings Velodyne LiDAR with Intel i7 CPU, which makes Real-Time GICP more efficient in when deployed on popular robotics computational platforms.
Ion-Molecule Collision Cross-Section Simulation using Linked-cell and Trajectory Parallelization

Ion Mobility coupled to Mass Spectrometry (IMMS) has become a highly valued tool for structural characterization of biological samples. In IM-MS the protein under investigation is ionized and accelerated by an electric field into a drift tube where it collides against a buffer gas. The separation of the gas-phase ions is then measured through the differences in their rotationally averaged Collision Cross-Section (CCS) values. The utility of the measured CCS for structural characterization critically depends on the validation against its theoretical calculation, which relies on intensive molecular mechanics simulation. Increasing the performance of CCS simulation is thus a relevant computational-chemistry research problem. This work shows that the combination of a linked-cell based algorithm with parallelization techniques can considerably increase the performance of CCS simulation. Experimental results reveal speedups from $\sim \mathbf{10}\times$ up to $\sim \mathbf{400}\times$ and parallelization efficiency greater than 0.98 when compared to High Performance Collision Cross Section (HPCCS), an optimized solution for CCS simulation. This reduces the CCS computation time from hours to minutes for a large range of proteins, making the proposed method the most performant approach to this problem nowadays, to the best of our knowledge.
A New Adaptive Feedforward Flux-Weakening Control Method of Aerospace Motor for More Electric Aircraft

This paper proposes an adaptive feedforward flux-weakening control (AFFWC) method of aerospace motor for more electric aircraft (MEA). Due to the requirement of wide speed adjustment of the MEA, the feedforward flux-weakening system is applied in the control of MEA motor. The flux-weakening method is improved to meet the requirement better on responding speed for MEA by using linear approximation method. An extended state observer (ESO) is designed to give the real-time status feedback to the flux-weakening system, and observe the disturbance. A nonlinear controller (NC) replacing the speed loop is used to eliminate the total disturbance observed by ESO. The NC can quickly fit the state error and give a torque command according to the proposed model to overcome the shortcomings that the original system is easily affected by the parameters disturbances. Finally, a load torque observer based on position signal is set up and the feedforward compensation method is used to improve the AFFWC and compensate the torque considering the disturbance of load torque. The feasibility and effectiveness of the proposed method are verified by experiments on an aerospace motor for MEA.
Bandwidth extension of continuous class-F power amplifier with phase-shifted voltage waveform

This paper presents a method for bandwidth extension in high-efficiency power amplifier (PA) design. With a phase shift in voltage waveform of the continuous class-F mode, real part of harmonic impedance is generated to expand the impedance design space at the expense of little lossy of performance. The simulation and measurement, conducted on a broadband PA covering 1.9-3.1 GHz based on the proposed method, show a good agreement with the theory. Measured results show that the fabricated PA has a drain efficiency of 66.5%-75% when delivering 41-42.3 dBm output power with a gain of 11-12.7 dB. Under a 20-MHz LTE signal excitation at 2.6 GHz, the PA exhibits an adjacent channel leakage ratio of -36.5 dBc at an average output power of 35 dBm without linearization.
Denoising and Analysis of PPG Acquired From Different Body Sites Using Savitzky Golay Filter

Photoplethysmogram (PPG) signals are often assessed using the transmission and reflection techniques, which detect light passed through or reflected by tissue. The transmission technique is appropriate for body sites with thin tissue, such as the index finger. In contrast, the reflection approach applies to most body sites. As each body site impacts inducing noise while acquiring PPG, this study investigates the quality of PPG signal obtained from five body sites, i.e., fingertip, forehead, toe, wrist-upper, and wrist-lower. After denoising with the Savitzky Golay filter, we calculated popular state-of-the-art parameters to quantify the obtained denoised signal to indicate the quality of PPG. Simulation results after denoising and analysis reveal that the PPG acquired from fingertip exhibits the highest quality and yields a signal-to-noise ratio $SNR=39.8672dB$ with a minimum percentage root mean square difference $(PRD)$ of 1.0154 as compared to the PPG acquired from other body sites.
Analysis and Optimization of Cogging Torque for Axial Flux Machine with Halbach Permanent Magnet Array

Axial flux permanent magnet synchronous machine (AFPMSM) has the advantages of high power density and excellent efficiency, which is widely used in electric vehicles, renewable energy and so on. The AFPMSM with yokeless and segment armature (YASA) has cogging structure that lead to cogging torque, which will deteriorate torque performance and operating conditions. Halbach permanent magnet array that has the characteristics of unilateral magnetic aggregation, which can improve the sine degree of air gap flux density. In this paper, the analytical model of YASA is derived by the conformal transformation and complex air gap flux conductance. Based on the analytical model, the air gap flux density distribution and cogging torque of YASA are calculated. The results obtained by analytical model are greet agreement with those obtained by finite element analysis(FEA). On this basis, the influence of 90° Halbach permanent magnet array on the YASA’s torque performance is analyzed. The analysis results show that the cogging torque and torque ripple of YASA can be greatly reduced, and the average torque can be improved by adopting a reasonable proportion of main and auxiliary poles.
Outage Constrained Secure Beamforming for IRS-Assisted Cognitive Radio Networks

This paper proposes a secure beamforming scheme to enhance the physical layer security (PLS) in the intelligent reflecting surface (IRS) assisted cognitive radio networks (CRNs). Taking the statistical channel state information (CSI) error of eavesdroppers (Eves) related channels into account, we jointly optimize the transmit beamforming at the cognitive base station (CBS) and reflect beamforming at the IRS to minimize the transmit power subject to the quality of service of secondary user (SU), the limited interference on the primary users (PUs), the secrecy rate (SR) outage probability constraint of SU and unit modulus of the IRS. To tackle this mathematically intractable problem, we first transform the non-convex outage constraint into deterministic form by using the Bernstein-type inequality and then exploit the alternating optimization method with the help of semi-definite relaxation (SDR) and Gaussian randomization method. Simulation results show that our proposed algorithm can significantly reduce the transmit power compared with that without IRS, and allows us to use fewer antenna number of CBS.
The Derivative of |X′X| and Its Uses

The determinant of matrices of the form X′X is used as the D-optimal design criterion for parameter estimation in nonlinear regression and as the estimation criterion for multiresponse parameter estimation. It is helpful to be able to calculate the gradient of this determinant so that sophisticated optimization methods can be used. A method is given to efficiently compute the determinant using modern computational linear algebra and, at the same time, to provide the necessary information to compute the gradient. The method is extended to cases in which a part of the X matrix is fixed. Examples from multiresponse parameter estimation and from experimental design are given.
Teager Energy Cepstral Coefficients For Classification of Dysarthric Speech Severity-Level

Dysarthria is a neuro-motor speech impairment that renders speech unintelligibility, which is generally imperceptible to humans w.r. t severity-levels. Dysarthric speech classification acts as a diagnostic tool for evaluating the advancement in a patient's severity condition and also aids in automatic dysarthric speech recognition systems (an important assistive speech technology). This study investigates the significance of Teager Energy Cepstral Coefficients (TECC) in dysarthric speech classification using three deep learning architectures, namely, Convolutional Neural Network (CNN), Light-CNN (LCNN), and Residual Networks (ResNet). The performance of TECC is compared with state-of-the-art features, such as Short-Time Fourier Transform (STFT), Mel Frequency Cepstral Coefficients (MFCC), and Linear Frequency Cepstral Coefficients (LFCC). In addition, this study also investigate the effectiveness of cepstral features over the spectral features for this problem. The highest classification accuracy achieved using UA-Speech corpus is 97.18%, 94.63%, and 98.02% (i.e., absolute improvement of 1.98%, 1.41%, and 1.69%) with CNN, LCNN, and ResNet, respectively, as compared to the MFCC. Further, we evaluate feature discriminative capability using $F1$-score, Matthew's Correlation Coefficient (MCC), Jaccard index, and Hamming loss. Finally, analysis of latency period w.r. t. state-of-the-art feature sets indicates the potential of TECC for practical deployment of the severity-level classification system.
New Methods for Fast Detection for Embedded Cognitive Radio

Spectrum Sensing is an important part of Cognitive Radio (CR) process. It can be used to determine if a Primary User (PU) (i.e. a licensed user) is emitting or not in the communication channel. This paper presents and compares three types of FFT-based detection algorithms for LTE-Advanced (LTE-A) cellular network at Orthogonal Frequency Division Multiple Access (OFDMA) level. These detectors sense the usage of the minimum time-frequency called Resource Block (RB). They are also low latency detectors and they only need one particular Orthogonal Frequency Division Multiplexing (OFDM) symbol to detect the usage of one RB. The three new detectors are based respectively on energy, correlation, and one what will be called eogration which combines energy and correlation. We analyze them with the Fisher's ratio and simulations of hypothesis test. The computing complexity of these detectors is also theoretically analyzed to provide guidance for future implementations.
MI-SISL Based 5G High-Efficiency Power Amplifier (invited)

This paper gives a brief introduction of the proposed metal-integrated and substrate integrated suspended line (MI-SISL) technology, which is demonstrated as an attractive plat-form for high power and high-efficiency power amplifier integration with superiorities of high-performance and self-packaging and two MI-SISL based high power and high-efficiency power amplifiers (PAs) for 5G applications are introduced as the demonstration cases.
Design of Battery Charger and Discharger using Series-input and Parallel-output connected DAB Converter

Recently, as the demand for DC/DC converters increases, a lot of research on DC/DC converters is being conducted. In particular, as a high-power DC/DC converter is required for rapid battery charging and discharging, a modular series-parallel converter system capable of accommodating it is required, and an appropriate control method for such a converter is required. Therefore, in this paper, a modular series-input parallel-output battery charger and discharger is implemented by using a DAB DC/DC converter that can be soft-switched, can secure insulation because it uses a transformer, and can use power in both directions. In addition, to effectively control this, we propose a new battery charger/discharger controller that performs smooth operation and protection operation when changing the CC-CV mode, and solves the voltage imbalance on the input side. The operating characteristics of the proposed series-input parallel-output DAB DC/DC converter for battery charging and discharging were verified through experiments and simulations.
A Five-Level Inverter Based On Reference Vector Decomposition

Compared with the three-level converter, five-level converter has the advantages of low harmonic content of output current, good waveform quality of voltage and current, and low switching loss. However, the space vector modulation technology of five-level converter has the problems of many vectors and complex control. To solve this problem, this paper proposes a five-level simplification algorithm based on reference vector translation. This algorithm makes full use of the mature space vector modulation technology of a two-level converter. First, the five-level space vector is simplified to three-level SVPWM modulation, and then the three-level SVPWM modulation is simplified to the two-level SVPWM modulation. And based on MATLAB/Simulink simulation platform and dSPACE hardware in the loop simulation platform, the five-level simplification algorithm is deeply studied. Simulation and experimental results verify the effectiveness of the strategy proposed in this paper.
A Linear Antenna Array with High Front-to-Back Ratio for Base Station Applications

In this paper, a linear dual-polarized antenna array with high front-to-back ratio (FBR) is designed for base station applications. The design process of the array topology is described, and a combined method of dielectric blocks and metal baffles is proposed for FBR enhancement. The dielectric blocks above the antenna elements and the metal baffles between the adjacent elements help to retain the radiation pattern and sup-press the backward radiation. A dual-polarized cross-dipole antenna array with dielectric blocks and metal baffles is designed and simulated. The FBR is enhanced by around 6 - 9 dB across the working frequency range from 700 to 960 MHz, while maintaining good impedance matching and compact arrangement.
Space vector modulation direct torque control of high speed permanent magnet synchronous motor based on five-level inverter

Due to the unique electromagnetic design of high-speed Permanent Magnet Synchronous Motor (HPMSM), the stator inductance value is small, which will cause problems such as stator current harmonics and excessive torque ripple in operation. Multilevel inverter can produce more levels and make the output voltage of inverter closer to sine wave. Direct Torque Control (DTC) has the advantages of simple algorithm and fast response, and is widely used in the control system of high-speed PMSM. However, multilevel inverters have many vectors and complex algorithms. Therefore, this paper proposes a simplified five-level Space Vector Pulse Width Modulation (SVPWM) algorithm and applies it to Space Vector Modulated Direct Torque Control (SVM-DTC). The proposed SVM-DTC strategy based on simplified five-level SVPWM can effectively reduce the calculation amount and reduce the harmonic content of stator current and torque ripple, so that the motor drive has good steady state and dynamic performance. The proposed method is simulated in MATLAB/SIMULINK software, and compared and analyzed with the three-level SVM-DTC system. This method can inhibit the harmonic content of stator current and torque ripple obviously.
Ternary rare-earth metal oxide high-k layers on silicon oxide

Ternary oxides, GdScO3, DyScO3, and LaScO3, deposited by pulsed laser deposition using ceramics targets of stoichiometric composition, were studied as alternative high-k gate dielectrics on (100) Si. Their physical characterization was done using Rutherford backscattering, spectroscopic ellipsometry, x-ray diffraction, and transmission electron microscopy on blanket layers deposited on (100) Si, and electrical characterization on capacitors. It is found that DyScO3 and GdScO3 preserve their amorphous phases up to 1000°C. Other encouraging properties for high k applications were demonstrated, including k-value ∼22, almost no hysteresis or frequency dispersion in C–V curves, and leakage current reduction comparable to that of HfO2 of the same equivalent oxide thickness.
Opportunistic Temporal Spectrum Coexistence of Passive Radiometry and Active Wireless Networks

There is insufficient wireless frequency spectrum to support the continued growth of active wireless technologies and devices. This has provoked extensive research on spectrum coexistence. One case that has gained limited attention in this course is using currently banned frequency bands for active wireless communications. One such option is the 27 MHz-wide narrowband portion of the L-band from 1.400 to 1.427 GHz, which is exclusively devoted to space-borne passive radiometry for remote sensing and radio astronomy. Radio regulations currently prohibit active wireless communications and radars from operating in this band to avoid radio frequency interference (RFI) on highly noise-sensitive passive radiometry equipment. The National Aeronautics and Space Administration’s (NASA’s) Soil Moisture Active Passive (SMAP) satellite is one of the latest space-borne remote sensing missions that evaluates global soil moisture by passive scanning of the thermal emissions of the earth in this frequency band. In this paper, we investigate the opportunistic temporal use of this 27 MHz-wide passive radiometry band for active wireless transmissions when there is no Line of Sight (LoS) between SMAP and a terrestrial wireless network. We use MATLAB simulations to determine the fraction of time that SMAP has LoS (and non-LoS) with a terrestrial wireless cell at different Earth latitudes based on SMAP’s orbital characteristics. We also investigate the severity of RFI induced on SMAP in the presence of a terrestrial cluster of 5G cells with LoS.
Constant Current Precision of Flyback LED Driver with Primary Side Control

In recent years, the application of LED is more and more extensive, and the constant-current accuracy requirement of the flyback LED driver controlled by the original side is also increasing. In this paper, the constant current error of the flyback LED driver controlled by the original side is analyzed, and on this basis, the two errors are compensated one by one. An adaptive Toff time compensation scheme is proposed, which can detect the Toff time error in different states in real time, so as to compensate the error well and achieve high constant current accuracy. In addition, a variable with Vin is introduced to compensate the sampling error of the original peak current by adjusting the external resistance. The experimental results show that through the above compensation action, the constant current accuracy can be controlled within 0.3 %, so as to meet the engineering requirements for constant current accuracy.
Circular Patch Resonator Loaded Compact SIW Filter with Harmonic Suppression

In this paper, based on a hybrid structure using the patch resonator and substrate integrated waveguide (SIW) cavity, a compact bandpass filter (BPF) with a wide stopband is proposed. The patch resonator is connected with two SIW cavities by coplanar waveguide lines at both ends. It can not only extend the order of the proposed filter but also suppress the TE201and TE202 modes of the SIW cavity. In addition, the offset orthogonal ports can prevent the propagation of the $\mathbf{TE}_{102}$ mode of the SIW cavities. Thus, a wide stopband is achieved by suppressing the first three spurious modes. For validation, a prototype was fabricated and measured.
Deep Learning of OpenStreetMap Images Labeled Using Road Traffic Accident Data

Identifying potentially high-risk areas is an important task for preventing road traffic accidents. In this paper, we present an attempt to train deep Convolutional Neural Networks (CNNs) on OpenStreetMap (OSM) images, each of which is labeled “high-risk” or “low-risk” using the data of road traffic accidents occurred in Okayama Prefecture, Japan from 2010 to 2021. It is shown that the trained CNNs can correctly predict whether a prescribed area is high-risk or low-risk only from the corresponding OSM image with a high probability. We also present some results of applications of Grad-CAM to the trained CNNs in order to visualize their decision making process.