Miracle-dz/UniFAR-FTUs huggingface dataset:
A New Fault Tolerant Control Method for a Three Phase Modular Multilevel Converter Under an Arm Failure

Modular multilevel converter (MMC) is widely used in medium to high power applications. One of the significant features that an MMC can provide is the fault tolerant operation, which improves the reliability of the converter. Although there are extensive efforts towards addressing the fault tolerant operation of a modular multilevel converter, the control of a three phase MMC when one of its arms is out of service, therefore, must be bypassed, is not yet discussed. The objective of the paper is to overcome this problem, by proposing a control method, which allows to control separately, the voltages of the capacitors in the upper and lower arms, except for the voltages of the capacitors belonging to the bypassed arm. In order to meet these requirements, the injected circulating current in each phase must contain a DC component, but also an AC component, oscillating at the fundamental frequency. The feasibility of the proposed fault tolerant method has been confirmed by simulations conducted on a three phase MMC connected to a low voltage grid using MATLAB/SIMULINK.
A Novel Decision-making Framework for Lane Change Considering Intentions of Traffic Participants

Drivers' lane-changing behavior is limited by road-ways, adjacent traffic, etc. A lane-changing maneuver consists of whether, when, and how to change lanes. This paper proposes a lane-changing decision-making framework that considers these three processes. This framework incorporates lane-changing intention identification, generation, and planning. First, the Gaussian Hidden Markov model identified traffic vehicles' lane-changing intentions. This determines the ego vehicle's lane-changing intention and longitudinal safety corridor. The ego vehicle's lane-changing trajectory is designed using a fifth-degree polynomial to assure continuous acceleration and zero acceleration at the start and end positions. Finally, simulation findings reveal that the proposed lane change decision-making framework can predict traffic vehicles' lane-changing intentions 1.7 seconds (on average) in advance. Like a driver, the proposed method can make lane-changing decisions in advance.
Time-Series Forecasting: Extreme Gradient Boosting Implementation in Smartphone Photoplethysmography Signals for Biometric Authentication Processes

Biometric Authentication (BA) is a process where behavioral and physiological inputs are used to determine the identity of individuals. Photoplethysmogram (PPG) is commonly used to provide physiological information of patients, such as heart rate and breathing rate. With technological advances, smartphones can provide PPG information without any external hardware. In this paper, we propose a BA system based on PPG readings. Features were selected by considering possible unique physiological factors during the period when PPG signals are acquired. We adopted the eXtreme Gradient Boosting (XGBoost) algorithm as a classification model. As performance metrics, we considered accuracy, specificity, and equal error rate (EER). Experimental results show that the average training accuracy, specificity, and EER values are 97.36%, 99.94%, and 0.06%, respectively, while the average testing accuracy, specificity, and EER values are 96.38%, 99.57%, and 0.43%, respectively.
On an integral formula for differential forms and its applications on manifolds with boundary

Abstract Given two k-forms α and β on a compact Riemannian manifold M with boundary ∂M, we derive an identity relating to an integral on the boundary ∂M. Herein Fk is a bundle endomorphism depending only on the Riemannian curvature tensor. Essential is how the tangential and normal parts of α and β, respectively their derivatives, appear in the integrand of the boundary integral. The identity gives a very simple proof for many classical results, which require that α = β and also that the tangential part αT (or the normal part αN) vanishes on ∂M. Moreover we generalize some of the boundary conditions in Gaffney inequality and in nonexistence theorems for harmonic fields.
Tackling Sexual Harassment: Short and Long Run Experimental Evidence from India∗

Sexual harassment imposes substantial economic costs on the victims yet, there is limited evidence on how to effectively deter it. I show that men can be successfully engaged to reduce sexual harassment using an RCT targetting sexual harassment awareness training at men and women separately in colleges in New Delhi. I show that the training with men reduces overall sexual harassment by 0.06 sd with a 100% decrease in extreme forms of harassment reported by women in their peer groups. The training also reduces romantic relationships between men and women in the short to medium run. I find that this is driven by women’s choices, using a lab-in-the-field experiment in which women prefer to cooperate with women rather than men on an experimental task. Using a signalling framework, I show that this is consistent with some men undertaking “good” behaviours even though they would prefer to harass women, to avoid disapproval from their peers. Consistent with this, men’s perception of peer disapproval against sexual harassment increased without a detectable change in their intrinsic attitudes towards it. Long-run surveys over one to two years after the intervention indicate a decline in overall sexual harassment albeit weakly and a persistent and stronger decline in opposite sex relationships. I cannot reject a null effect on sexual harassment and opposite sex relationships of a similar intervention that was delivered exclusively to women in a separate college. JEL codes: D91, J16, J28, K42, O12.
A competitive 3D-Volleyball-Game using Reinforcement Learning with Unity ML-Agents

This project report describes the integration of reinforcement learning into a game development scenario by creating a competitive volleyball game using the Unity ML-Agents Toolkit. The work elaborates on what reinforcement learning is, brings forth some of the challenges of adding machine learning to a game, describes the development environment Unity and its machine learning package ML-Agents. Furthermore the implementation aspects are described including the environment setup, parameter tuning, reward engineering as well as the performance analysis of the trained agent.
Multiple quantum wells for ring and linear lasers with long lifetime gain

Various solid state lasers such as Cr:LISAF, Yb:YAG, Nd:Vanadate, Ti:sapphire and Nd:YAG have in common a long lifetime of the laser level, which results in a tendency to Q-switching rather than pure mode-locking. These lasers are being used in a linear or ring cavity for intracavity sensing applications (displacements, rotation, electric and magnetic fields), and for applications in spectroscopy. The requirements for these applications are that the pulses be centered at a specific wavelength, and be of a specific pulse duration. Multiple Quantum Wells (MQW) typically used for ultrashort pulse generation have often a high defect concentration which causes losses incompatible with the large number of intracavity elements required by the applications. We have established for all these lasers a composition curve for the MQW, that enables one to tune to a specific wavelength. These saturable absorbers have excellent optical quality both in reflection and transmission. The approach to prevent Q-switching has generally been to use very low loss modulation (single quantum wells). With a large number of intracavity elements, a larger loss modulation is desirable, hence the use of multiple QW (4 to 100). We have successfully demonstrated stable continuous model-locked operation by using passive energy limiters in the cavity. Two-photon generated carriers induce lensing in the cavity, resulting in power dependent losses through an aperture in the cavity. We show that the attenuation is proportional to the square of pulse intensity, resulting in a steep energy limiter. We demonstrate theoretically and experimentally that the presence of two intracavity pulses required for sensor applications can be satisfied with multiple quantum wells appropriately positioned in the cavity. Examples of applications include rotation sensors (ring cavity) or acceleration sensors (linear cavity), magnetic filed sensor, displacement sensors.
Cascading Alignment for Unsupervised Domain-Adaptive DETR with Improved DeNoising Anchor Boxes

Transformer-based object detection has recently attracted increasing interest and shown promising results. As one of the DETR-like models, DETR with improved denoising anchor boxes (DINO) produced superior performance on COCO val2017 and achieved a new state of the art. However, it often encounters challenges when applied to new scenarios where no annotated data is available, and the imaging conditions differ significantly. To alleviate this problem of domain shift, in this paper, unsupervised domain adaptive DINO via cascading alignment (CA-DINO) was proposed, which consists of attention-enhanced double discriminators (AEDD) and weak-restraints on category-level token (WROT). Specifically, AEDD is used to aggregate and align the local–global context from the feature representations of both domains while reducing the domain discrepancy before entering the transformer encoder and decoder. WROT extends Deep CORAL loss to adapt class tokens after embedding, minimizing the difference in second-order statistics between the source and target domain. Our approach is trained end to end, and experiments on two challenging benchmarks demonstrate the effectiveness of our method, which yields 41% relative improvement compared to baseline on the benchmark dataset Foggy Cityscapes, in particular.
Sub-pixel registration method for phase diversity wavefront sensor using spatial light modulator

The purpose of this paper is to develop sub-pixel registration method for adaptive optics system using phase diversity wavefront sensing with a spatial light modulator (SLM). The SLM which is used for wavefront compensation applies multiple time-series known wavefronts as a priori information to the optical system. By using the SLM for the phase diversity generator, it is possible to select the optimal number and shape of phase diversities for various kinds of natural modes of wavefront aberrations which are represented by the Zernike polynomials. In this case, a misregistration of several diversity images has to be compensated before using phase diversity algorithm. We extracted phase diversity method to estimate not only wavefront aberration but also parallel shift between images simultaneously. The suggested method was validated by numerical simulations, and the high estimation accuracy of the distorted wavefront was demonstrated, and nearly diffraction limited images were acquired by wavefront compensation by preventing noise due to misregistrations.
Adaptive Order Polynomial Fitting: Bandwidth Robustification and Bias Reduction

Abstract This article deals with estimation of the regression function and its derivatives using local polynomial fitting. An important question is: How to determine the order of the polynomial to be fitted in a particular fixed neighborhood? This depends on the local curvature of the unknown curve. A higher order fit leads to a possible bias reduction, but results in an increase of variability. A precise evaluation of this increase is presented, and from this it is also clear that it is preferable to choose the order of fit adaptively. In this article we provide, for a given bandwidth, such a data-driven variable order selection procedure. The basic idea is to obtain a good estimate of the mean squared error at each location point and to use this estimate as a criterion for the order selection. The performance of the proposed selection procedure is illustrated via simulated examples. It turns out that the adaptive order fit is more robust against bandwidth variation; even if the bandwidth varies by a fac.
Implications of x‐ray emission from lightning

Dwyer et al. [2003 , 2004a] recently reported measurements of bursts of x‐rays, with energies up to ∼250 keV, originating from dart leaders and possibly the return strokes of rocket‐triggered lightning. In this paper, these x‐ray observations are compared with the relativistic runaway electron avalanche (RREA) model. It is found that for dart leaders the standard RREA model is inconsistent with the observed spectrum and flux of the x‐ray emission. This result implies that the cold runaway electron model may be applicable to dart leaders. In this model, runaway electrons are directly accelerated out of the bulk electron population, produced by the ionization of the neutral atoms. However, this mechanism requires an electric field an order‐of‐magnitude larger than the conventional breakdown field. Because the flux of runaway electrons is very sensitive to the electric field strength, x‐ray observations of lightning provide a novel tool for determining the fields associated with the leaders.
A Simple Kinematic Source of Skewness in Atmospheric Flow Fields

AbstractGeopotential height fields exhibit a well-known pattern of skewness, with distributions that are positively skewed on the poleward side of the midlatitude jets/storm tracks and negatively skewed on the equatorward side. This pattern has often been interpreted as a signature of nonlinear dynamical features, such as blocking highs and cutoff lows, and there is renewed interest in the higher moments of flow variables as indicators of the nature of the underlying dynamics. However, this paper suggests that skewness can arise as a simple kinematic consequence of the presence of jet streams and so may not be a reliable indicator of nonlinear dynamical behavior. In support of this, reanalysis data are analyzed to demonstrate a close link between the jet streams and the skewness patterns. Further evidence is provided by a simple stochastic kinematic model of a jet stream as a Gaussian wind profile. The parameters of this model are fitted to data from the reanalysis and also from an aquaplanet general circ.
Enhanced second harmonic generation from nanoscale double-hole arrays in a gold film

We present enhanced second harmonic generation (SHG) from arrays with a basis of overlapping double holes. The arrays were created by focused-ion beam milling through a gold film, and the measurements were performed in the transmission geometry. By fixing the array periodicity and varying the spacing between the holes, the SHG was enhanced by an order of magnitude for the single case where the apexes of the double-hole structure were nearly touching. Numerical calculations showed a local electric field enhancement that agrees with the SHG observations. This work shows the potential of double-hole structures for nonlinear optics at the nanoscale.
Measurements of relative transition probabilities and the variation of the electronic transition moment for N2 C3Πu-B3 Πg second positive system

Accurate values of the relative transition probabilities Aupsilon ' upsilon '' for 41 bands in the N2 second positive system have been measured using single-photon counting techniques on a repetitive pulsed source. A computer code simulating the band structure, including multiplet splitting, and intensity distribution enables any band intensity to be deduced from the fractional intensity seen at the peak in the P branch (band-head). The variation of the electronic transition moment with internuclear separation Re(r) is obtained from the measured Aupsilon ' upsilon '' by means of a weighted least-squares curve-fitting procedure based on nth moment r centroids. It is best represented by a polynomial of degree 2, (1-1.336r+0.487r2) whose curvature is in the opposite sense to previously derived fits.
The soft-mode instability of a membrane induced by strong polymer adsorption

The interaction between a flexible polymer and a fluctuating membrane is a fundamental problem in soft-matter physics with relevance to biological phenomena occurring in cells. We find that polymer fluctuations in a strongly adsorbed state can renormalize the bending rigidity of a planar membrane to a negative value. It gives rise to a novel phenomenon that the membrane with a small surface tension can be unstable to spontaneous formation of a soft mode, i.e., a large-amplitude undulation with the wavelength comparable to the interaction range which can be long.
Rarefaction and Compressibility Effects in Gas Microflows

Gas microflows are encountered in many applications of Micro-Electro-Mechanical Systems (MEMS). Computational modeling and simulation can provide an effective predictive capability for heat and momentum transfer in microscales as well as means of evaluating the performance of a new microdevice before hardware fabrication. In this article, we present models and a computational methodology for simulating gas microflows in the slip-flow regime for which the Knudsen number is less than 0.3. The formulation is based on the classical Maxwell/Smoluchowski boundary conditions that allow partial slip at the wall. We first modify a high-order slip boundary condition we developed in previous work so that it can be easily implemented to provide enhanced numerical stability. We also extend a previous formulation for incompressible flows to include compressibility effects which are primarily responsible for the nonlinear pressure distribution in microchannel flows. The focus of the paper is on the competing effects of compressibility and rarefaction in internal flows in long channels.
Characteristics of a radial line slot antenna for 12 GHz band satellite TV reception

Characteristics of a novel planar antenna which can radiate a circularly polarized pencil beam in x -band are presented for the application of receiving direct broadcast from a satellite. This antenna belongs to a class of slotted waveguide antennas and promising performances, especially its high efficiency, have already been predicted theoretically. The measured performance of a model antenna with a diameter of 0.6 m, is presented. Antenna gain of about 35 dBi and axial ratio of about 1 dB are realized at 12.2 GHz; the associated antenna efficiency of 57 percent is very high in comparison with that of the conventional microstrip antennas, in this range of gain.
Speak, memory—Wherefore art thou, invariance?

Spoken language is highly variable, reflecting factors of environmental (e.g., acoustic-background noise, reverberation), linguistic (e.g., speaking-style), and idiosyncratic (e.g., voice-quality) origin. Despite such variability, listeners rarely experience difficulty understanding speech. What brain mechanisms underlie this perceptual resilience, and where does the invariance reside (if anywhere) that enables the signal to be reliably decoded and understood? A theoretical framework—DejaNets—is described for how the brain may go from “sound to meaning. ” Key is speech representations in memory, crucial for the parsing, analysis, and interpretation of sensory signals. The acoustic waveform is viewed as inherently ambiguous, its interpretation dependent on combining data streams, some sensory (e.g., visual-speech cues), others internal, derived from memory and knowledge schema. This interpretative process is mediated by a hierarchical network of neural oscillators spanning a broad range of time constants (c.
Some aspects of total scattering cross sections of electrons for simple hydrocarbon molecules

Total electron scattering cross sections for C2H4, C2H6, C3H6 (propene and cyclopropane) and C3H8 have been measured in the energy range between 4 and 500 eV. Measured results show a remarkable isomer effect and dependence on the geometrical dimension of the molecule.
High‐resolution spectroscopy of two metal‐poor red giants: HD 232078 and HD 218732

An abundance analysis for 35 chemical elements based on a high-resolution (R = 67 000) optical spectra of two metal-poor ([Fe/H] ≈ - 1.50) halo red giants, HD 232078 and HD 218732, is presented. Abundances of 10 chemical elements were derived for the first time. Both red giants are chromospherically active and optically variable, located close to the red giant branch tip. Abundances of both stars generally follow typical halo star abundance distribution, while HD 218732 should have experienced a deep mixing episode and could be a first ascent asymptotic giant branch star.
Minimax control problems of periodic competing parabolic systems with logistic growth terms

In this article, we consider a bioeconomic model for minimax control problems which are governed by periodic competing parabolic Lotka-Volterra equations. Firstly, the existence and uniqueness results to the state equations are proved as well as stability under mild assumptions. Afterwards, we formulate the minimax control problem. The optimality criteria are to minimize damage and trapping costs of the first species (nuisance), and to maximize the difference between economic revenue and cost of the second species. The existence of an optimal solution is obtained. Also, necessary conditions for a saddle point optimality are derived.
A Greedy Algorithm for Capacitated Lot-Sizing Problems

We show that the convex hull of the set of feasible solutions of single-item capacitated lot-sizing problem (CLSP) is a base polyhedron of a polymatroid. We present a greedy algorithm to solve CLSP with linear objective function. The proposed algorithm is an effective implementation of the classical Edmonds' algorithm for maximizing linear function over a polymatroid. We consider some special cases of CLSP with nonlinear objective function that can be solved by the proposed greedy algorithm in O ( n ) time.
Quantum-engineered mid-infrared type-II InAs/GaSb superlattice photodetectors for high temperature operations

Over the last several years, owing to the implementation of advanced device architectures, antimony-based type-II superlattice (T2-SL) infrared (IR) photodetectors and their focal plane arrays (FPAs) have achieved significant advancements. Here we present our recent effort towards the development of high operating temperature (HOT) mid-IR (MWIR) photodetectors, which utilizes an interband cascade scheme with discrete InAs/GaSb SL absorbers, sandwiched between electron and hole barriers. This low-noise device architecture has enabled background-limited operation above 150 K (300 K, 2π field-of-view), as well as above room temperature response in the mid-IR region. The detector yields a dark current density of 1.10×10-7 A/cm2 (1.44×10-3 A/cm2) at -5 mV, and a Johnson-limited D* of 2.22×1011 cmHz1/2/W (1.58×109 cmHz1/2/W) at 150 K (room temperature) and 3.6 μm, respectively. In this presentation, we will discuss the operation principles of the interband cascade design and our most recent progress in MWIR photodetectors toward high operating temperatures.
The preferred spatial mode of instability for a Mach 2 jet

Phase-averaged schlieren video and an array of azimuthally oriented microphones were used in the experiments performed to determine the preferred spatial structure associated with supersonic nozzle design for an exhaust Mach number of 2. The jet flow was unheated, chemically inert, and submerged in a static environment, conditions that are satisfactory for the quasi-linear wave-analytical model of Tam and Morris (1980) and Tam and Burton (1984). For general conditions of undeterminate phase-averaged optical records, a conditional sampling method was devised, based on fundamental multimode components. This method uncovers the preferred spatial structure, and shows that in addition to the dominant jet flapping mode, there is also a significant contribution from the axisymmetric mode. Near-field correlations with a moving microphone indicate that the flapping plane is nearly stationary, and not spinning as in the Westley and Wolley (1975) experiment.