Miracle-dz/UniFAR-FTUs huggingface dataset:
Design of SIW Coupling Structure Applied in PMF Transmission System

In this paper, a substrate integrated waveguide (SIW) coupling structure is proposed for polymer microwave fibers (PMF) transmission system. Compared with the previous coupling structures applied in PMF transmission systems， the proposed structure has smaller lateral dimension and much higher coupling efficiency because the SIW structure has smaller loss. Besides, due to the use of SIW structure, this coupling structure is more suitable for integration compared with traditional ways. The simulation results show that the proposed structure has an operating bandwidth from 95 GHz to 105 GHz and the coupling efficiency reaches 86%.
Wideband Dual-Polarization phased-array antenna With High Isolation

A wideband dual-polarization antenna with high isolation for the phased array applications has been proposed in this article. In order to meet the wideband and high isolation requirement, the array element uses dipole pairs with narrow-slot structure. The dual-polarization characteristic is achieved by exciting two orthogonal dipole patches. The working band of the antenna array is from 8 to 11 GHz with a relative bandwidth of 40%. The simulated results show that the active VSWR is less than 1.5 and 2.5 in the band 8 ~ 12 GHz while the range of scan angle is 0° and ±45°. The port isolation is below -30dB and the cross-polarization is below -30 dB across the whole band.
The Benefits of the Matthews Correlation Coefficient (MCC) Over the Diagnostic Odds Ratio (DOR) in Binary Classification Assessment

To assess the quality of a binary classification, researchers often take advantage of a four-entry contingency table called confusion matrix, containing true positives, true negatives, false positives, and false negatives. To recap the four values of a confusion matrix in a unique score, researchers and statisticians have developed several rates and metrics. In the past, several scientific studies already showed why the Matthews correlation coefficient (MCC) is more informative and trustworthy than confusion-entropy error, accuracy, F1 score, bookmaker informedness, markedness, and balanced accuracy. In this study, we compare the MCC with the diagnostic odds ratio (DOR), a statistical rate employed sometimes in biomedical sciences. After examining the properties of the MCC and of the DOR, we describe the relationships between them, by also taking advantage of an innovative geometrical plot called confusion tetrahedron, presented here for the first time. We then report some use cases where the MCC and the DOR produce discordant outcomes, and explain why the Matthews correlation coefficient is more informative and reliable between the two. Our results can have a strong impact in computer science and statistics, because they clearly explain why the trustworthiness of the information provided by the Matthews correlation coefficient is higher than the one generated by the diagnostic odds ratio.
A Compact Ultra-wideband Balun with Isolation Circuit

In this paper, we designed a compact ultra-wideband Marchand balun which achieved all-port matching and high isolation between the balanced ports with an isolation circuit (IC). To reduce the size, the transmission lines of balun are folded within 0.25 λg ×0.25 λg. The suggested balun achieved a return loss which is greater than -15dB at the unbalanced port from 3.8 to 17.8 GHz, with less than 1dB amplitude imbalance, and less than 5-deg phase imbalance. For the balanced ports, the simulated isolation between the balanced ports is greater than 15dB from 5 to 14 GHz and the return losses which greater than -15dB is from 2 to 14GHz.
Elimination of Current Harmonics in Electrical Machines with Iterative Learning Control

The magnitude of current harmonics depends on the design of an electrical machine. By suppressing these harmonics noise can be reduced and efficiency improved. Iterative Learning Control (ILC) has proven effective in reducing harmonics. One of the challenges of working with ILC is operation at varying speeds. Variable speeds are particularly important for applications like automotive drives. The ILC period length changes during the learning process at varying speeds. Due to fixed sample rates, the number of values processed by the ILC varies with motor speed.This paper proposes a method to solve this problem and uses ILC at varying speeds. The ILC used to eliminate the harmonics is based on the inverse system. The usage of a two-dimensional memory array is proposed. This data structure holds rows for specific speeds between which interpolation is performed, enabling the elimination of errors which are periodically cyclic to one electrical rotation. This includes the reduction of the motor current harmonics. To verify the presented method a permanent magnet synchronous motor with distinctive 5th and 7th harmonics is used. In real-time implementations, limitations of memory and computational capacity occur.
Suppressing spatially distributed disturbances by exploiting additional sensors and actuators in inferential motion control

Structural deformations resulting from exogenous disturbances limit the control performance in high-precision positioning systems. The aim of this paper is to identify these limitations and mitigate these through multivariable inferential control. A systematic analysis and control design framework is established. Herein, additional sensors and actuators are exploited to achieve control performance beyond conventional limits. Successful performance enhancement using the presented methods is shown on an identified wafer stage model.
K-Band Wideband Microstrip Antenna Array With Sidelobe Level Reduction

A single-layer, low-sidelobe, wideband microstrip antenna array is proposed in this paper using PCB technology. In order to overcome the problem of inherent narrow impedance bandwidth of microstrip antennas, two parasitic patches are loaded on both sides of the main radiation patch to expand the impedance bandwidth. In addition, Taylor distribution is introduced in the feeding network to reduce the sidelobe level. CPW-to-microstrip transition is introduced for probe feeding. Simulation results show that: the -10 dB impedance bandwidth is 15.5% from 21.4 to 25 GHz with a peak gain of 18.1 dBi. The simulated radiation patterns agree well with the measured ones which show -25 dB sidelobe level in the H-plane. Impedance matching performance is still under testing.
Design and Analysis of C-band repeater for Small Communication Satellite

This paper presents the design of a transparent Cband repeater for small geostationary (GEO) communication satellite. The repeater configurations and key units proprieties are introduced besides the payload specifications and the frequency plan. In this work, the repeater is based on eight (08) channels configuration with redundancy in active units, the transponder gain budget is also calculated to fulfil the payload requirements.
The nanoscale electrical imaging by using the near-field microwave microscopy method

The scanning near-field microwave microscope (SNMM) was developed to qualitatively image the nanoscale electrical properties of materials at the microwave frequency range. The microwave probe was designed based on a quartz tuning fork (TF) glued with the electrochemically etched metal wires. The sensitivity and signal-to-noise-ratio of the measurement were improved by a two-port interferometric matching circuit. A standard grating sample was measured to validate the topography resolution and the microwave imaging function of this system.
Design and Fabrication of Patch Antenna Array on Quartz Glass Substrate at 146 GHz

In this paper, the printed D-Band patch antenna and 1×4 array antenna are designed on the quartz glass substrate, which are suitable for millimeter wave applications. The central frequency of the antenna array is designed at 146 GHz. Because there are no metal vias in the quartz glass substrate, the gold belt is utilized to connect the signal ground on the top surface with the antenna ground on the bottom of substrate. The relative position of the gold belt affects the resonant frequency of the antenna. The prototypes of the antennas are successfully fabricated and measured. The measured gain of patch antenna unit and antenna array are 6.6 dBi and 11.4 dBi, respectively, at 146 GHz. The S11 below -10 dB bandwidth are about 6.4% and 5.9%, respectively.
On the Generation of E-Learning Resources Using Business Process, Natural Language Processing, and Web Services

E-learning resources are pieces of knowledge used for achieving a learning objective. One of the problems in e-training in the workplace has to do with the lack of relevance of learning resources. Here, we define a learning resource as a resource that contains information about a task or refers to a task realized within the context of an organizational process. We describe a set of activities for the generation of learning resources of objective, content, activity, and assessment types, which correspond to the pedagogical elements in learning objects. The generation goes from a documented business process using natural language processing and the learning resources produced are packaged as web services for independence and reusability purposes. Each learning resource generated is independent since it may participate in several formative sequences on its own, and it is reusable since it may be used many times without any change.
Lightweight Encryption Technique to Enhance Medical Image Security on Internet of Medical Things Applications

The importance of image security in the field of medical imaging is challenging. Several research works have been conducted to secure medical healthcare images. Encryption, not risking loss of data, is the right solution for image confidentiality. Due to data size limitations, redundancy, and capacity, traditional encryption techniques cannot be applied directly to e-health data, especially when patient data are transferred over the open channels. Therefore, patients may lose the privacy of data contents since images are different from the text because of their two particular factors of loss of data and confidentiality. Researchers have identified such security threats and have proposed several image encryption techniques to mitigate the security problem. However, the study has found that the existing proposed techniques still face application-specific several security problems. Therefore, this paper presents an efficient, lightweight encryption algorithm to develop a secure image encryption technique for the healthcare industry. The proposed lightweight encryption technique employs two permutation techniques to secure medical images. The proposed technique is analyzed, evaluated, and then compared to conventionally encrypted ones in security and execution time. Numerous test images have been used to determine the performance of the proposed algorithm. Several experiments show that the proposed algorithm for image cryptosystems provides better efficiency than conventional techniques.
Load Torque Control of an Electromagnetic Motor with a Reduction Gear, a Spring, and Motor/Load-Side Encoders

Actuators that have characteristics such as a light weight, high torque-to-weight ratio, and good torque control performance are desirable for application in finger robots and power-assist suits. Although electromagnetic motors excel in torque control performance, they have low torque-to-weight ratios. Adding reduction gears gives them high torque-to-weight ratios, but backlash and friction degrade torque control performance. This paper therefore proposes a load torque control system using an electromagnetic motor with a reduction gear, a spring, and motor/load-side encoders. The effectiveness of the proposed control system is verified via simulation and experiment.
Thermal design of an asynchronous machine within the project NeWwire

The goal of the research project „Neuartige serienflexible Wickelverfahren für die wirtschaftliche automatisierte Fertigung von hoch performanten elektrischen Maschinen (NeWwire)" funded by the Federal Ministry of Education and Research is to develop an innovative winding process that allows the automated manufacturing of high performance electrical machines for the automotive sector. The consortium partners at the University of Kassel are responsible for the electromagnetic and thermal design of an asynchronous machine while considering especially the requirements related to the manufacturing process.This paper describes the investigation and optimization of thermal aspects within the project. It presents system modelling using thermal network models as well as experimental testing and measurement-based model validation.
The Actor-Critic Algorithm for Infinite Horizon Discounted Cost Revisited

Reinforcement Learning (RL) is a methodology used to solve Markov decision processes (MDPs) within simulators. In the classical Actor-Critic (AC), a popular RL algorithm, the values of the so-called actor become unbounded. A recently introduced variant of the AC keeps the actor’s values naturally bounded. However, the algorithm’s convergence properties have not been established mathematically in the literature. Numerically, the bounded AC was studied under the Boltzmann action-selection strategy, but not under the more popular ε-greedy strategy in which the probability of selecting any non-greedy action converges to zero in the limit. The paper revisits the AC framework. A short review of the existing literature in the growing field of ACs is first presented. Thereafter, the algorithm is investigated for its convergence properties, under ε-greedy action selection, numerically on a small-scale MDP, as well as mathematically via the ordinary differential equation framework.
Coupled Control Lyapunov Functions for Interconnected Systems, With Application to Quadrupedal Locomotion

This letter addresses the problem of formally guaranteeing the stability of interconnected systems with local controllers with a view toward stabilizing quadrupeds viewed as coupled bipeds. In particular, we present a novel framework that views general rigid-body systems as a collection of lower-dimensional systems that are coupled via reaction forces. Stabilizing the corresponding coupled control system can thus be addressed by stabilizing each subsystem coupled through the passive dynamics. The main results of the letter are stability conditions that guarantee convergence for each control subsystem by formulating coupled control Lyapunov functions (CCLFs) using the notion of input-to-state stability (ISS). This theoretical result is illustrated via a simple cart-pole example, where exponential stability is obtained. Next, building on previous results where an 18-DOF quadrupedal robot is decomposed into two interconnected bipedal systems for efficient periodic gait generation, we design model-free quadratic programs (QPs) using the CCLFs to stabilize the continuous dynamics and thus achieve experimental walking and simulated hopping and running on the Vision 60 quadrupedal robot.
The Offline Virtual Network Function Packing Problem

This paper presents the offline Virtual Network Function Packing (VNF-P) problem, a new challenging optimization problem that telecom operators face when designing the cloud infrastructure to host virtual network functions, especially in the context of 5G networks deployment. The VNF-P problem is a generalization of the classical Bin Packing Problem, where VNFs are packed onto physical servers, while taking into account capacity constraints, variable bin size and cost, conflicts between items and between items and bins, some unsplittable items, and two-compartment bins. Our contributions to this problem include a formal definition of the VNF-P problem, exact procedures and heuristic algorithms to solve it. An efficient algorithm, providing a good quality lower bound by solving a relaxation of the problem, is also provided. Numerical experiments on realistic instances were conducted in order to compare the different approaches. They show that the classical results of the literature cannot be extended naturally to this variant. The proposed algorithms have been validated on real use-case studies at Orange, and have been embedded in an operational tool to design the future cloud infrastructure.
Deep learning-based automated optical inspection system for crimp connections

Within the trend of electrification and autonomous driving, the significance of high-quality crimp connectors is increasing as they establish the electrical connection for the energy and information flow in the automotive system. Whereas the manufacturing of crimp connectors is highly automated, the final quality assessment mainly comprises manual optical inspection tasks that are human labor-intensive and time-consuming. Addressing this gap, a computer vision system to automate the final inspection of crimp connectors is proposed and implemented. In this paper, the image processing chain and the deep learning-based model to reason over image data of crimp connectors with regard to different defect classes are outlined. The effectiveness of this system using a dataset collected in the laboratory environment is demonstrated.
A Comprehensive Review of Speech Emotion Recognition Systems

During the last decade, Speech Emotion Recognition (SER) has emerged as an integral component within Human-computer Interaction (HCI) and other high-end speech processing systems. Generally, an SER system targets the speaker’s existence of varied emotions by extracting and classifying the prominent features from a preprocessed speech signal. However, the way humans and machines recognize and correlate emotional aspects of speech signals are quite contrasting quantitatively and qualitatively, which present enormous difficulties in blending knowledge from interdisciplinary fields, particularly speech emotion recognition, applied psychology, and human-computer interface. The paper carefully identifies and synthesizes recent relevant literature related to the SER systems’ varied design components/methodologies, thereby providing readers with a state-of-the-art understanding of the hot research topic. Furthermore, while scrutinizing the current state of understanding on SER systems, the research gap’s prominence has been sketched out for consideration and analysis by other related researchers, institutions, and regulatory bodies.
Survey on Object Detection in Aerial Imagery

Object detection is a process of locating and identifying entities in an image or video. It is a fundamental process in many real-life applications. It can be used for aerial images to detect different objects, which can be used for tasks like surveillance and analysis. Being a crucial process in these applications it is also a challenging problem. It involves challenges like obscured objects, cluttered backgrounds, unpredictable orientations, and comparatively small-scale objects for detection. Along with this aerial image gives overhead view of objects which makes feature extraction difficult and can cause false alarm. In practice, an object and classification detection model are often required to perform well in terms of speed and detection accuracy. Although many traditional detection models have shown a decent performance result by using the multiple templates in a sliding-window manner and imagery pyramid, these methods are still inefficient. Satellite images contain vast information for processing and analysis, but the human eye is not able to recognize the little changes like intensity color and texture. To extract information from aerial images, a segmentation method could be applied which is a difficult and important task in image analysis. This can be primarily done through edge detection, wavelet-based method, and multispectral classification. The customary detection techniques have made remarkable progress with horizontal bounding boxes (HBBs) because of CNNs. Nevertheless, HBB detection techniques still have some limitations that include missed detection and redundant detection regions, especially for densely clustered and strip shaped objects. This paper gives a detailed study and discussions on the idea of existing techniques for detection of objects in aerial images.
An Effective Use of Synthetic Aperture Radar Imaging Technique Over Optical Remote Sensing and Real Aperture Radar for Mapping of Earth Surface Features

Remote sensing is rightly described as an activity of recording/ observing/ perceiving (sensing) objects or events that are located at far away (remote) places. In remote sensing, the sensors are not in direct physical contact with the objects or events that are being observed. The information to be sensed needs a physical carrier (say, microwave) to travel from objects/events to the sensing device through an intervening medium (clouds, water vapour, air). Normally, the electromagnetic wave is used as an information carrier. The output of a remote sensing system is usually an image (bi-spectral (grayscale)/trispectral (RGB)/ hyperspectral (many bands)) representing the scene which is being observed. Further steps of image analysis and interpretation(visual/machine) is required in order to extract useful information from the recorded image. In general sense, the human visual system is a classic example of a remote sensing system. Data in the form of 2-D images which are mapped from optical remote sensing, after going through a series of processing steps, is ready for human interpretation and can be used for several applications like mapping of land cover, classification of various crops, in weather forecasting and monitoring, etc. However, the problems of constant cloud coverage and other atmospheric disturbances dominantly persist in optical images that often lead to erroneous data interpretation. So, in order to correctly interpret the mapped mages from satellite or aeroplane platforms, we have to rely on the data received from synthetic aperture radar (SAR) that has this unique capability to operate nearly under all weather conditions. Also, SAR imaging used by space-crafts is advantageous over any other method of earth feature mapping (i.e. optical, thermal) as it uses energy harnessed from its on-board solar panels to recharge its batteries and in turn generate the microwave bursts of energy, which it then transmits towards the surface of the earth. The primary aim of this paper is to illustrate the crucial point of differences between optical and radar remote sensing and how a real aperture radar (RAR) imaging technique differs from its counterpart i.e. synthetic aperture radar (SAR) in terms of range, azimuth resolution. We have also discussed as to how we can conceptualize a SAR antenna using the properties of RAR.
Development of Reluctance Actuator for High-Precision Positioning and Scanning Motion

To utilize the high force of reluctance actuators for high-precision fast scanning motion, this paper presents a nanopositioner that integrates two reluctance actuators for a bidirectional force and investigates its achievable performance. A challenge of reluctance actuators is their force-current nonlinearity. To model it accurately for compensation, a displacement sensor for real-time motion control is utilized to measure the force curves. A model based on the experiments is used to compensate for the nonlinearity by means of feedback linearization. It successfully decreases a total harmonic distortion of sinusoidal scanning trajectories from 25 % to 2.6 %, which is further improved to 1.45 % by linear position feedback control. The achieved bandwidth and the positioning resolution are 335 Hz and 2 nm. Additionally, feedforward control is designed, and sinusoidal scanning motions at 1 Hz and 100 Hz are evaluated for a feasibility study to find out challenges and potentials of reluctance actuators.