Miracle-dz/UniFAR-FTUs huggingface dataset:
Exact Synthesis of Unequal Power Division Filtering Rat-Race Ring Couplers

Exact synthesis of unequal power division filtering rat-race ring couplers is proposed. The power division property results from the half-symmetric core ring structure of the proposed couplers. The proposed core ring was modified from the equal power division rat-race ring in 2015 where the core ring in that circuit is fully symmetric. Due to the half-symmetry of ring and unequal power division characteristics, the signal excitation and circuit partition methods in 2015 cannot be applied. In this paper, the modified signal-excitation method and the source-division technique are proposed to reduce the original four-port rat-race ring couplers into the corresponding two-port networks. These two-port networks can be exactly synthesized by the S-domain filter synthesis method. Alternatively, the simplified design equations are proposed. Using these equations, the rat-race ring hybrid in 2015 can be transformed into the arbitrary power division rat-race ring couplers. Therefore, the final rat-race ring couplers are provided with some user-defined specifications, such as the unequal power division, the input/output impedance transformation, the center frequency, the fractional bandwidth, and the return loss level. Two fifth-order filtering rat-race ring couplers with 3- and 10-dB power division are implemented as examples; in addition, these couplers are with a center frequency of 2 GHz, a fractional bandwidth of 100%, a return loss level of 20 dB, and the input/output impedance transformation of 50/70 $\Omega $ . The measured and simulated results indicate good agreement.
Classifying Neuromorphic Data Using a Deep Learning Framework for Image Classification

In the field of artificial intelligence, neuromorphic computing has been around for several decades. Deep learning has however made much recent progress such that it consistently outperforms neuromorphic learning algorithms in classification tasks in terms of accuracy. Specifically in the field of image classification, neuromorphic computing has been traditionally using either the temporal or rate code for encoding static images in datasets into spike trains. It is only till recently, that neuromorphic vision sensors are widely used by the neuromorphic research community, and provides an alternative to such encoding methods. Since then, several neuromorphic datasets are obtained by applying such sensors on image datasets (e.g. the neuromorphic CALTECH 101) have been introduced. These data are encoded in spike trains and hence seem ideal for benchmarking of neuromorphic learning algorithms. Specifically, we train a deep learning framework used for image classification on the CALTECH 101 and a collapsed version of the neuromorphic CALTECH 101 datasets. We obtained an accuracy of 91.66% and 78.01% for the CALTECH 101 and neuromorphic CALTECH 101 datasets respectively. For CALTECH 101, our accuracy is close to the best reported accuracy, while for neuromorphic CALTECH 101, it outperforms the last best reported accuracy by over 10%. This raises the question of the suitability of such datasets as benchmarks for neuromorphic learning algorithms.
NSNI Mitigation in Bi-Directional Raman Amplified Unrepeatered System Using Split-DBP

The nonlinear signal–noise interaction (NSNI) is analyzed in the bi-directional Raman amplified unrepeatered system with digital back-propagation (DBP) algorithm. When the DBP is applied at the receiver side, because in the DBP process the spontaneous Raman scattering is not dealt with, extra NSNI occurs, and because of the high power in the system, the extra NSNI is severe. By adopting split-DBP, the interaction of noise and signal in the high-power region could be avoided. Thus, the extra NSNI was mitigated and the performance was improved. The performance of split-DBP algorithm in such a system was investigated through simulations and experiments, using a single-channel 300-km bi-directional Raman amplified unrepeatered system. The simulations were carried out with 16 QAM modulation and the modulation rates were 32 GBd and 10 GBd. The results showed that the split-DBP can deliver 0.8-dB Q 2-factor improvement for the case of 32 GBd and 1.3 dB for the case of 10 GBd, compared to the traditional DBP. The impact of the nonlinear transform function of modulator and power profile mismatch on the performance of split-DBP is discussed through the simulation, which is critical to the practical implementation of split-DBP. An experimental demonstration of the split-DBP with 10 GBd 16 QAM modulation was carried out. The experimental results presented a 1.2-dB Q2-factor improvement of the signal due to split-DBP.
A 16-Element W-Band Phased-Array Transceiver Chipset With Flip-Chip PCB Integrated Antennas for Multi-Gigabit Wireless Data Links

This paper describes the design and implementation of a W-band phased-array system with printed circuit board (PCB) integrated antennas in two polarizations capable of multi-gigabit spectrally efficient wireless communication. The chipset is manufactured in a 0.18- $\mu \text{m}$ SiGe BiCMOS technology with $f_{T}/f_{\mathrm {MAX}}$ of 240-/270-GHz and is flip-chipped onto a low-cost organic PCB with integrated antenna arrays. Each chip is equipped with 16-transmit/4-receive or 16-receive/4-transmit calibrated phase shifter elements and direct up- and downconverters plus a half-rate phase-locked loop. The different system tradeoffs required to establish a multi-Gb/s wireless link at millimeter waves are carefully studied. Built-in element failure detectors, power detectors, and digital interface enable factory calibration and self-test capability. Each transceiver chip operates from 1.5- and 2.5-V supplies and consumes 5.5 and 4.5 W in transmit and receive mode, respectively. The peak transmitter effective isotropic radiation power is 34 dBm in each polarization with a measured receiver noise figure of 6.5 dB at 94 GHz. At a distance of 1 m, a maximum wireless data rate of 30 Gb/s (per polarization) using 64-QAM can be achieved and at 20 m, 8 Gb/s (dual polarization) can be established using QPSK modulation.
Approaches for integration of educational computer games in e-learning environments

The interest of educators in Game-based education and gamification of the educational process has grown rapidly in recent years. The important questions are: What kind of game development tools are to be used and how to use and deliver appropriate educational games in e-learning environments? In this paper we propose a framework for analyzing the possibilities for game and gamification integration in e-learning environments. On the basis of this framework we have made an analysis of features of popular free open source e-learning environments like Moodle, A Tutor, and ILIAS. In addition, we present examples of integration of educational computer games in e-learning environment Moodle.
Comparing ecophysiological traits in two Podarcis wall lizards with overlapping ranges

In ectotherms, environmental factors shape the distribution of species mediated by ecophysiological constraints such as thermal requirements and water stress. Species with different distributions along an environmental gradient are expected to show contrasting responses in thermal-gradient and water-stress lab experiments. We examined basic thermal and hydric physiological traits throughout the day in two related lizard species with different, but partially overlapping, distributions in the Iberian Peninsula: Podarcis liolepis (abundant but mostly restricted to northeastern Iberia) and P. muralis (restricted in Iberia but widespread across Europe). We expected P. liolepis to opt for higher preferred body temperatures and have lower water loss rates as compared to P. muralis. Surprisingly, results revealed no differences in preferred body temperatures between species or sexes. Conversely, interspecific differences in the temporal profiles of water loss were found. Results suggest that water availability rather than thermal environment shapes the biogeographical patters of both species.
A 2D Ray-Tracing Based Model for Wave Propagation Through Forests at Micro-and Millimeter Wave Frequencies

This paper proposes the extension of a 2-D ray-tracing-based model for radiowave propagation in the presence of trees and vegetation areas to include real-sized trees and outdoor forest scenarios. The original propagation model proved to be suitable to characterize the electromagnetic behavior in the presence of indoor tree formation scenarios, despite some limitations found when applied to real-sized trees. In addition, the original propagation model requires the prior knowledge of the trees’ re-radiation function to extract the relevant propagation input parameters, which is not always possible to obtain in outdoor scenarios. Therefore, an empirical method to extract the relevant input propagation parameters based on simple measurements is proposed. The performance of the proposed propagation model extension is extensively assessed in both the line-of-trees and tree formation scenarios, including various (and mixed) species, both in- and out-of-leaf foliation states, and at three signal frequencies. Finally, depending on the type of scenario, a benchmark between the proposed propagation model and both the radiative energy transfer (RET) and discrete RET (dRET) models, for line-of-trees and tree formation, respectively, is presented.
Joint Energy Management and Interference Coordination With Max-Min Fairness in Ultra-Dense HetNets

Interference management and energy management are two important issues in ultra-dense heterogeneous cellular networks (HetNets). However, load balancing investigated for system capacity on interference coordination is not efficient for energy saving in HetNets. Meanwhile, the maximum energy efficiency configuration leads to the serious unfair problem for users associated with larger power node for the ultra-dense scenario. Thus, in this paper, we investigate energy consumption jointly together with interference coordination for ultra-dense HetNets, and formulate max-min energy-efficient enhanced inter-cell interference coordination configuration problem. Due to the non-smooth and mixed programming nature of this formulation, we propose a novel iterative and distributed algorithm to solve the problem by using fractional programming and Lagrangian dual theory. The simulation results verified the effectiveness of our proposed algorithm and fairness achieved for energy efficiency of users, it especially identified a new energy efficiency tradeoff between macro user and small cell user with interference coordination in ultra-dense HetNets.
Effects of temperature and salinity stress on DNA methylation in a highly invasive marine invertebrate, the colonial ascidian Didemnum vexillum

Environmentally induced epigenetic changes may contribute to phenotypic plasticity, increase adaptive potential in changing environments, and play a key role in the establishment and spread of invasive species in new habitats. In this study, we used methylation-sensitive amplified polymorphism (MSAP) to assess environmentally induced DNA methylation changes in a globally invasive clonal ascidian, Didemnum vexillum. We tested the effect of increasing temperature (19, 25 and 27 °C) and decreasing salinity (34, 32, 30, 28 and 26 practical salinity units (PSU)) on global DNA methylation, growth and survival rates. Exposure to 27 °C resulted in significant changes in DNA methylation over time. Growth also decreased in colonies exposed to high temperatures, suggesting they were under thermal stress. In contrast, no differences in growth nor DNA methylation patterns were observed in colonies exposed to a decreasing salinity gradient, potentially due to prior adaptation. The results of this study show that environmental stress can induce significant global DNA methylation changes in an invasive marine invertebrate on very rapid timescales, and that this response varies depending on the type, magnitude, and duration of the stressor. Changes in genomic DNA methylation and the rate of growth may act to ‘buy survival time’ under stressful conditions, expanding the distribution limits of this globally invasive species.
Broadband Terahertz Detection With Zero-Bias Field-Effect Transistors Between 100 GHz and 11.8 THz With a Noise Equivalent Power of 250 pW/$\sqrt{\text{Hz}}$  at 0.6 THz

We demonstrate UV contact lithographically fabricated III–V field-effect transistors (FETs) examined over a bandwidth of 100 GHz–11.8 THz. The zero-bias device reaches a noise equivalent power as low as 250 pW/ <inline-formula><tex-math notation="LaTeX">$\sqrt{\text{Hz}}$</tex-math></inline-formula> at 0.6 THz, which then increases as <inline-formula><tex-math notation="LaTeX">$f^4$</tex-math></inline-formula> at higher frequencies. The responsivity is modeled by a simple equivalent circuit, showing good agreement over the frequency range of two decades. The FETs have been characterized using a photomixer, a quantum cascade laser, and a free-electron laser, proving the versatility and large applicability of the detection concept.
Sleep Architecture in Patients With Primary Snoring and Obstructive Sleep Apnea

Introduction: This study aimed to investigate sleep architecture in patients with primary snoring and obstructive sleep apnea. Methods: In this study, we analyzed polysomnographic data of 391 clients who referred to Sleep Disorders Research Center (SDRS). These people were classified into three groups based on their Apnea-Hypopnea Index (AHI) and snoring; control, Primary Snoring (PS), and Obstructive Sleep Apnea (OSA) group. Sleep architecture variables were then assessed in all groups. Results: The results of this study indicated a decrease in deep sleep or Slow Waves Sleep (SWS) and increase in light sleep or stage 1 of non-REM sleep (N1) in OSA patients compared with the control and PS groups. After controlling the effects of confounding factors, i.e. age and Body Mass Index (BMI) (which was performed through multiple regression analysis) significant differences were observed among the three groups with regard to N1. However, with regard to SWS, after controlling confounding variables (age and BMI), no significant difference was found among the groups. Conclusion: The results indicated that OSA, regardless of age and BMI, may increase light (N1) sleep possibly via a decline in blood oxygen saturation (SpO2 ). Such increase in N1 may be responsible for brain arousal. In addition, by controlling confounding factors (age and BMI), OSA did not affect SWS in OSA patients. However, further research is necessary to determine sleep architecture in more detail in the patients with OSA.
A High-Power, Medium-Voltage, Series-Resonant Converter for DC Wind Turbines

A new modulation scheme is introduced for a single-phase series-resonant converter, which permits continuous regulation of power from nominal level to zero, in presence of variable input and output dc voltage levels. Rearranging the circuit to locate the resonant LC tank on the rectifier side of the high turns-ratio transformer combined with frequency control and phase-shifted inverter modulation keep transformer flux constant from nominal frequency down to dc, always in subresonant continuous or discontinuous conduction mode. This overcomes the principal deficit of series-resonant converters, and the resulting compact and efficient transformer, and soft-commutated inverter, present particular advantages in high-power, high-voltage applications, such as dc offshore wind turbines. With transformer excitation frequency in hundreds of Hz range, line-frequency diodes can be employed in the high-voltage rectifier valve. Circuit operation and conduction modes, governing equations, and sample waveforms are presented, together with experiments from a scaled demonstrator.
Digital Beamforming-Based Massive MIMO Transceiver for 5G Millimeter-Wave Communications

A 64-channel massive multiple-input multiple-output (MIMO) transceiver with a fully digital beamforming (DBF) architecture for fifth-generation millimeter-wave communications is presented in this paper. The DBF-based massive MIMO transceiver is operated at 28-GHz band with a 500-MHz signal bandwidth and the time division duplex mode. The antenna elements are arranged as a 2-D array, which has 16 columns (horizontal direction) and 4 rows (vertical direction) for a better beamforming resolution in the horizontal plane. To achieve half-wavelength element spacing in the horizontal direction, a new sectorial transceiver array design with a bent substrate-integrated waveguide is proposed. The measured results show that an excellent RF performance is achieved. The system performance is tested with the over-the-air technique to verify the feasibility of the proposed DBF-based massive MIMO transceiver for high data rate millimeter-wave communications. Using the beam-tracking technique and two streams of QAM-64 signals, the proposed millimeter-wave MIMO transceiver can achieve a steady 5.3-Gb/s throughput for a single user in fast mobile environments. In the multiple-user MIMO scenario, by delivering 20 noncoherent data streams to eight four-channel user terminals, it achieves a downlink peak data rate of 50.73 Gb/s with the spectral efficiency of 101.5 b/s/Hz.
Automatic Analysis of Expected Termination Time for Population Protocols

Population protocols are a formal model of sensor networks consisting of identical mobile devices. Two devices can interact and thereby change their states. Computations are infinite sequences of interactions in which the interacting devices are chosen uniformly at random. In well designed population protocols, for every initial configuration of devices, and for every computation starting at this configuration, all devices eventually agree on a consensus value. We address the problem of automatically computing a parametric bound on the expected time the protocol needs to reach this consensus. We present the first algorithm that, when successful, outputs a function f(n) such that the expected time to consensus is bound by O(f(n)), where n is the number of devices executing the protocol. We experimentally show that our algorithm terminates and provides good bounds for many of the protocols found in the literature.
Performance variation of morphed face image detection algorithms across different datasets

In past years, different researchers have shown the vulnerability of face recognition systems to attacks based on morphed face images. More recently, first morph detection subsystems have been proposed to automatically detect this kind of fraud. While some algorithms have been reported to reveal practical detection performance on individual datasets a systematic analysis of proposed detectors with respect to their robustness across different databases has remained elusive. In this work, we evaluate the performance of different morph detection algorithms across disjoint datasets of 2,745 bona fide and 14,337 automatically generated morphed face images. Within a generic evaluation framework a systematic robustness estimation scheme is proposed to identify reliable detection algorithms. Finally, the robustness of algorithms which have been determined as most promising is verified on another disjoint dataset. Hence, this paper represents the first attempt towards a comprehensive cross-database performance evaluation and a systematic evaluation of the robustness of morphed face image detection algorithms.
Small-Signal Model of the Two-Phase Interleaved Coupled-Inductor Boost Converter

A coupled-inductor dc–dc converter has several modes of operation in continuous-conduction mode (CCM) and discontinuous-conduction mode (DCM), and is quite complex. This paper presents the derivation of the complete small-signal model of a two-phase interleaved dc–dc boost converter utilizing a single-core coupled-inductor operating in both CCM and DCM. Several small-signal models are required to fully model the converter due to the complexity of the converter operating in DCM. The transfer functions are then derived from these small-signal models. The theoretical analysis is validated experimentally using frequency sweeps from a 1-kW prototype.
Studies on electric field distribution and partial discharges of XLPE cable at DC voltage

Partial discharge (PD) detection is considered as a reliable method to analyze the operating status of the electrical equipment. But there are only a few literatures about PDs of cross-linked polyethylene (XLPE) cable at DC voltage. So this paper mainly concentrates on electric field distribution and PD phenomena of DC XLPE cable. Numerical simulation method is applied to analyze electric field distribution in normal and four typical insulation defect (corona defect, cavity defect, scratch defect and creepage defect) models. Electro-thermal coupling model is established to solve this problem. The simulation result shows that four defects can cause different electric field distortion. Among them, corona defect has the most serious distortion and creepage defect has the most slightly distortion. The high voltage test is applied to verify the simulation result. The H(q, Δt) spectrums of PD signals confirm that serious electric field distortion can cause severe PD phenomena.
Equivalent accelerated aging method to evaluate long-term performance of metalized film capacitor for voltage source converter application

Metalized film capacitor (MFC) with ultrahigh power is one of the key power devices in High Voltage Direct Current (HVDC) power transmission technology, and the evaluation of its long-term performance (especially its lifetime) is of great importance for reliability of HVDC system. But those experiments require enormous power supply capacity which is difficult to achieve in laboratory. In this paper, we propose a feasible equivalent experiment method to evaluate long-term performance of ultrahigh power MFC, which employs floating aging at elevated temperature and voltage level imitating electric and thermal effect in operating condition. Thermal effect of ripple current has been equalized as temperature rise of 14.7°C according to finite element analysis and temperature rise experiment, and the enhanced strength of electric field caused by the ripple voltage has been equalized as voltage rise of 196V. The equivalent method proposed enables laboratory study on long-term performance of ultrahigh power MFC.
Performance Analysis of Indoor THz Communications with One-Bit Precoding

In this paper, the performance of indoor Terahertz (THz) communication systems with one-bit digital-to- analog converters (DACs) is investigated. Array-of- subarrays architecture is assumed for the antennas at the access points, where each RF chain uniquely activates a disjoint subset of antennas, each of which is connected to an exclusive phase shifter. Hybrid precoding, including maximum ratio transmission (MRT) and zero-forcing (ZF) precoding, is considered. The best beamsteering direction for the phase shifter in the large subarray antenna regime is first proved to be the direction of the line-of-sight (LoS) path. Subsequently, the closed-form expression of the lower- bound of the achievable rate in the large subarray antenna regime is derived, which is the same for both MRT and ZF and is independent of the transmit power. Numerical results validating the analysis are provided as well.