Miracle-dz/UniFAR-FTUs huggingface dataset:
Virtual Holonomic Constraints for Euler-Lagrange Systems

Abstract This paper investigates virtual holonomic constraints for Euler-Lagrange systems with n degrees-of-freedom and n − 1 controls. The constraints have the form q1 = ϕ1 (qn), …, qn – 1 = ϕn ∓ 1 (qn), where qn is a cyclic configuration variable, so their enforcement corresponds to the stabilization of a desired oscillatory motion. We give conditions under which such a set of constraints is feasible, meaning that it can be made invariant by feedback. We show that it is possible to systematically determine feasible virtual constraints as periodic solutions of a scalar differential equation, the virtual constraint generator. Moreover, under a symmetry assumption we show that the motion on the constraint manifold is a Euler-Lagrange system with one degree-of-freedom, and use this fact to complete characterize its dynamical properties. Finally, we show that if the constraint is feasible then the virtual constraint manifold can always be stabilized using input-output feedback linearization.
Miniature Air Coupled Ultrasound Data Acquisition System for Field Application of Resonance Spectroscopy

Development of the complete ultrasonic data acquisition and processing system for resonance spectroscopy studies is presented. Sensor can be used in precision agriculture for plant physiological status evaluation. The whole data storage and processing system contains three parts: i) the front-end node (sensor); ii) gateway; iii) cloud storage and processing service. Moving the storage, processing and reports generation to clouds service ensures the flexibility. In such case the data storage is unlimited. Also, any modification in processing algorithm can be immediately implemented for all users, independent on their location. Front-end node is a portable palm-sized ultrasonic device. It is responsible for signals acquisition from the plant leaf and transmission to a smartphone. Structure of the sensor electronics and essential parameters measured are presented.
Hydrophone Spatial Averaging Correction for High-Frequency Arrays

A hydrophone spatial averaging correction algorithm, previously validated in the 5–8 MHz range [1, 2], was tested at higher frequencies using two high-frequency linear arrays: L12-5 (9 MHz; F/1.6) and L22-14 (15 MHz; F/3). Seven hydrophones (with capsule, needle, and membrane designs and sensitive element diameters ($d_{g}$) ranging from 85 to 1000 µm) were used, one at a time, to measure the beams at the focal point. Spatial averaging errors were characterized by percent change in parameter (peak compressional pressure $p_{c}$, peak rarefactional pressure $P_{r}$, pulse intensity integral pii, and spatial-peak temporal average intensity Ispta) measurement for every 100 µm of hydrophone sensitive element diameter. The spatial averaging correction algorithm reduced errors in measurements of $p_{c}$ from 11%±2 % to 3 %±2 % per 100 µm, measurements of $P_{r}$ from 7%±1% to 0%±4% per 100 µm and measurements of intensities from 12%±1% to 0%±2% per 100 µm. The spatial averaging correction was effective up to at least 15 MHz and resulted in significant reduction in errors of measurements for acoustic pressures and intensities from clinical high-frequency linear arrays.
Optical Receiver Front-End for 50G PON in 40nm CMOS

With the determination of the 50Gb/s PON communication network standard, there is a large demand for 50Gb/s PON chips. In this paper, we design a 50Gb/s transimpedance amplifier (TIA) chip with very low power consumption, which greatly reduces the manufacturing cost by adopting the 40nm standard CMOS process. In the high gain mode, the transimpedance gain is 66. 0dBΩ and the bandwidth is 30.4GHz. In the low gain mode, the transimpedance is 52. 4dBΩ and the bandwidth is 34.1GHz. The input signal range can reach 2mA at most and the maximum differential output swing is 440mVpp. The receiver front-end circuit consumes 23.4mW, and the energy efficiency is 0.47pJ/bit.
Shielding Design for High-Frequency Wireless Power Transfer System for EV Charging with Self-Resonant Coils

This paper provides a complete design solution for a 6.6 kW wireless power transfer system based on compact self-resonant (SR) coils with shielding considered. The high frequency parasitic capacitance introduced by the shielding material is analyzed in detail, and a shielding geometry optimization method is proposed. Using ferrite for shielding and a PTFE spacer, the total thicknesses of coils are only 11.4 mm and 7.4 mm for the transmitter and receiver, respectively. The system is validated with fabricated SR coils, achieving 92.3% DC-DC efficiency and 7.1 kW/dm3 volumetric power density. This paper demonstrates the first 6.6-kW WPT system for EV charging using compact self-resonant coils at MHz with practical shielding implementation.
Impacts of moisture on the thermal-oxygen pyrolysis of Kapton, a ReaxF MD simulation

Kapton-type polyimide films are always used as the solid insulation medium in many power-electronic devices, which will decompose due to the high temperature caused by the partial discharge in the open air. In order to explore the influence of moisture on the thermal-oxygen decomposition characteristics of Kapton, simulation models containing 1polyimide, oxygen and water molecules are established in this paper. The ReaxFF molecular dynamics simulation is applied to indicate the pyrolysis process of polyimide, as well as the changes in production of small molecules. The results show that the moisture will encourage the degradation of main chains of polyimide by aggravating the broken of imide ring. And in the short effect of unbalanced PD, the benzene ring the Kapton could not be broken.
Learning to reach to own body from spontaneous self-touch using a generative model

When leaving the aquatic constrained environment of the womb, newborns are thrown into the world with essentially new laws and regularities that govern their interactions with the environment. Here, we study how spontaneous self-contacts can provide material for learning implicit models of the body and its action possibilities in the environment. Specifically, we investigate the space of only somatosensory (tactile and proprioceptive) activations during self-touch configurations in a simple model agent. Using biologically motivated overlapping receptive fields in these modalities, a variational autoencoder (VAE) in a denoising framework is trained on these inputs. The denoising properties of the VAE can be exploited to fill in the missing information. In particular, if tactile stimulation is provided on a single body part, the model provides a configuration that is closer to a previously experienced self-contact configuration. Iterative passes through the VAE reconstructions create a control loop that brings about reaching for stimuli on the body. Furthermore, due to the generative properties of the model, previously unsampled proprioceptive-tactile configurations can also be achieved. In the future, we will seek a closer comparison with empirical data on the kinematics of spontaneous self-touch in infants and the results of reaching for stimuli on the body.
A Multi-Parameter Approach to Optimal Power Dispatch in Grid-Connected Photovoltaic-Battery Systems

In photovoltaic-battery energy storage systems (PV-BESSs), the optimal power dispatch between the power sources (PV, battery, and the grid) and the load demand is significant, from the viewpoint of system efficiency and household profit. In this paper, a method that considers the time-of-use pricing (TOU) of electricity, the PV feed-in-tariff, and battery lifetime is proposed for the optimal power dispatch of grid-connected PV-BESS systems during a 24-hour period. The proposed method is implemented for a residential PV-battery system using the genetic algorithm (GA) and real TOU electricity pricing data and PV feed-in-tariff data of London, ON, Canada. Simulation results show how the proposed method can result in the optimal power dispatch in the system and how user profit can be maximized.
Design of an Automatic Landslide and Earthquake Warning System in Rural Areas of Peru

This research presents the automatic design of a warning system for the prevention of landslides and earthquakes with mechatronic systems with IOT communication to speed up the evacuation process. The development of the project shows that the application of force sensors, optical sensors and the type of communication are feasible in each process since it is divided into 3 levels where the values of both teachers are contrasted to issue an alert. The alert emission stage comprises 2 processes, first when the collapse signal is detected and verified by both sensors, it will be communicated from the installed part and the nearby community by IOT communication, it will be powered by solar panel and/or batteries and second when there is seismic movement, the bases will detect these signals and emit another type of noise for the evacuation. Being Peru a highly seismic country with many rural areas with steep slopes, every second counts in these natural events.The design of the proposed system will help prevent the events that occur in case of landslides and earthquakes; which are material damage and loss of life, with the type of power it will remain active during the day and the friendly design will facilitate its understanding.
Educational Augmented Reality Serious Games for People with Developmental Disabilities: A Brief Review of the Research Literature

Many serious games have been developed over time to serve as support in the education of children with developmental disabilities. Augmented Reality (AR) is a technology whose popularity has been increasing, and many games are currently adopting it. Such innovation shows great potential to be applied in serious games. Therefore, this paper aims to explore the trends in the application of AR in serious games that enhance the education process of a child with a developmental disability. The objective is to supply the researcher with a structured table that incorporates key factors related to serious games. Multiple studies from 2016 to 2021 have been collected, and 15 were selected to be reviewed. Finally, it concludes that the results were positive regarding the effectiveness of the projects developed in the reviewed material, and there is still a lot of room for improvement and future work.
Accurate Radiation Impedance Analysis for CMUT Design

The transducer resonance frequency is a key parameter for the field of ultrasound. The resonance frequency in vacuum is well understood, and an analytical expression for the center frequency in immersion was derived by Lamb in 1920 [1], however this expression has limited validity. Importantly, the model fails to cover plate aspect ratios needed by imaging requirements and met by recently fabricated medical Capacitive Micromachined Ultrasonic Transducers (CMUTs). Based on the equation of motion a new expression for the resonance frequency in immersion is derived. The influence of the immersion medium is included via the radiation impedance, which is approximated using the well-known Taylor expansion, yielding results similar to Lamb's. For precision at smaller aspect ratios, this work proposes using the Padé approximant instead. Comparing the frequency ratio to FEM simulations, the Padé approximant shows a fourfold reduction in error from 12.0% to 3.0%.
A 6-18GHz Low-Noise Amplifier Using Noise Canceling Technique in 130-nm CMOS PD-SOI

This paper presents the design of a 6-18GHz low-noise amplifier (LNA) utilizing noise canceling technique to achieve large bandwidth and low noise figure (NF) simultaneously. The LNA is composed of three stages, resistive shunt feedback cascode topology is adopted for the first one, which is convenient for wideband input impedance matching. Besides, the second and third stage are designed for noise canceling and gain compensation respectively. Inductive peaking technique is employed to broaden the bandwidth. Implemented in 130-nm CMOS PD-SOI technology, the proposed LNA achieves maximum 15.44dB gain and minimum 2.42dB NF with flatness of ±1.44dB and 0.109dB/GHz respectively across 6-18GHz, whose fractional bandwidth is as large as 100%.
Loss Analysis of a High-Speed IPMSM using Different Trajectory Control

This paper investigates the loss performances of a high-speed interior permanent magnet synchronous motor under three different trajectory controls: maximum torque per ampere (MTPA) with and without considering core loss and maximum efficiency (ME) trajectories. The paper considers the variation of the equivalent core loss resistance by representing it using a function of currents and speed instead of the constant value used in conventional methods. An equation of MTPA considering variable core-loss-resistance was derived based on the equivalent circuit. The trajectories, efficiencies, and loss maps of the three control methods were compared and analyzed. The methods were applied to a high-speed IPMSM to compare their experimental efficiency improvements. Both analytical and experimental results show that ME and MTPA with variable core loss resistance make minor efficiency improvements when the core loss relative to the total loss is small in a well optimized high-speed IPMSM. Detailed analyses were carried out to identify the reasons behind the insignificant efficiency gain with the ME compared to the MTPA. It will be shown that the existing ME trajectory, which assumes constant core loss resistance, does not give the real maximum efficiency operating points. In the paper, the real maximum efficiency trajectory of the motor was found using a statistical method which was used to assess the effectiveness of ME over the MTPA for a high-speed IPMSM.
Long-distance SAW Sensor Interrogation

Wirelessly interrogated SAW sensors are an attractive option for sensing temperature, chemical environment, pressure, etc. However, the interrogation range in free space is severely limited due to the 1/R4 decline in signal strength, where R is the distance between the interrogator and the sensor. The use of waveguides, especially waveguides that are already part of the sensed environment, would greatly increase the useful interrogation distance. We report here on the use of pipes as a circular waveguide for SAW interrogation.
Acetabular Paralabral Cyst Causing Obturator Nerve Compression in the Setting of Femoroacetabular Impingement Syndrome

Case: Large acetabular paralabral cysts can cause compression of the surrounding neurovascular structures leading to sensory and motor deficits. We present a 68-year-old man with obturator nerve denervation from a paralabral cyst secondary to a labral tear associated with femoroacetabular impingement syndrome. Resolution of symptoms and return to full activities were achieved at 3 months and maintained beyond 1 year through open cyst excision, obturator neurolysis, arthroscopic femoral osteoplasty, and labral repair in the same surgical setting. The patient had a successful clinical outcome, with pain and dysfunction resolution. Conclusion: Large paralabral cysts may cause obturator nerve compression, which can be successfully treated with open nerve decompression and arthroscopic treatment of labral pathology.
Semiparametric Estimation of a Regression Model with an Unknown Transformation of the Dependent Variable

This paper shows how to estimate a model in which an unknown transformation of the dependent variable is a linear function of explanatory variables plus an unobserved random variable, U, whose distribution is unknown. The model nests many familiar parametric and semiparametric models, including models with Box-Cox transformed dependent variables and proportional hazards models with and without unobserved heterogeneity. The paper develops root-n consistent, asymptotically normal estimators of the transformation function, coefficients of the explanatory variables, and distribution of U. The results of Monte Carlo experiments indicate that the estimators work well in samples of size one hundred. Copyright 1996 by The Econometric Society.
Multimodal Cell-Free DNA Embeddings are Informative for Early Cancer Detection

Cell-free DNA is a promising biomarker for early cancer detection, as it circulates 1 in the blood and can be extracted non-invasively. However, methods of analysing 2 the genetic and epigenetic patterns present in cell-free DNA are outdated, and 3 fail to fully capture the wealth of biological information contained within these 4 molecules. We present a Transformer based deep learning model that combines the 5 three distinct modalities contained within cell-free DNA: epigenetic information 6 in the form of DNA methylation patterns, genetic sequence, and cell-free DNA 7 fragment length. After training on publicly available data, we demonstrate our 8 model can accurately distinguish liver cancer patients using cell-free DNA samples 9 alone. We demonstrate model generalisability by accurate classification of liver 10 cancer patients from entirely distinct patient cohorts. Finally, we show that the 11 vector embeddings of cell-free DNA learnt by this multimodal deep-learning model 12 are biologically informative, and may help shed light on the origins and aetiology 13 of this elusive bio-molecule. 14
Effect of mass loading on ionic polymer metal composite actuators and sensors

Ionic polymer metal composites (IPMC) actuator for flapping insect scale wing is advantageous due to its low mass, high deflection and simple actuation mechanism. Some of the factors that affect the actuation of IPMC are the amount of hydration in the polymer membrane and the environmental conditions such as temperature, humidity etc. In structural design, the attachment of wing on the IPMC actuators is an important concern as the attached wing increases the mass of actuators thereby affecting the parameters like displacement, stiffness and resonant frequencies. Such IPMC actuators have to produce sufficient actuation force and frequency to lift and flap the attached wing. Therefore, it is relevant to study the influence of attachment of wing on the actuator parameters (displacement, resonant frequency, block force and stiffness) and performance of the actuators. This paper is divided into two parts; the first part deals with the modeling of the IPMC actuators for its effect on the level of water uptake and temperature using energy based method. The modeling method adapted is validated with the experimental procedure used to actuate the IPMC. The second part deals with the experimental analysis of IPMC actuation at dry, wet and in water conditions. The effect of end mass loading on the performance of 20 Hz, high frequency actuator (HFA) and 8.7 Hz, low frequency IPMC actuators (LFA) and sensors is studied. The IPMC actuators are attached with IPMC flapping wing at its free end and performance analysis on the attached wing is also carried out.
Atomic form factors, incoherent scattering functions, and photon scattering cross sections

Tabulations are presented of the atomic form factor, F (α,Z), and the incoherent scattering function, S (x,Z), for values of x (=sin ϑ/2)/λ) from 0.005 A−1 to 109 A−1, for all elements A=1 to 100. These tables are constructed from available state‐of‐the‐art theoretical data, including the Pirenne formulas for Z=1, configuration‐into action results by Brown using Brown‐Fontana and Weiss correlated wavefunctions for Z=2 to 6 non‐relativistic Hartree‐Fock results by Cromer for Z=7 to 100 and a relativistic K‐shell analytic expression for F (x,Z) by Bethe Levinger for x≳10 A−1 for all elements Z=2 to 100. These tabulated values are graphically compared with available photon scattering angular distribution measurements. Tables of coherent (Rayleigh) and incoherent (Compton) total scattering cross sections obtained by numerical integration over combinations of F2(x,Z) with the Thomson formula and S (x,Z) with the Klum‐Nishina Formual, respectively, are presented for all elements Z=1 to 100, for photon energies .
Multivariate elliptic processes

We introduce and study multivariate elliptic processes, thus providing a dynamic counterpart to the (static) multivariate elliptic distributions. We pay special attention to the dynamics for Lévy processes and diffusions. We also discuss discrete versus continuous time modelling, jump processes versus diffusions, and semimartingales. Some data analysis illustrates the theory.
L1-Norm Sparse Learning and its Application

The need on finding sparse representations has attracted more and more people to research it. Researchers have developed many approaches (such as nonnegative constraint, l1-norm sparsity regularization and sparse Bayesian learning with independent Gaussian prior) for encouraging sparse solutions and established some conditions under which the feasible solutions could be found by those approaches. This paper commbined the L1-norm regularization and bayesian learning, called L1-norm sparse bayesian learning, which was inspired by RVM (relative vector machine). L1-norm sparse bayesian learning has found its applications in many fields such as MCR (multivariate curve resolution) and so on. We proposed a new method called BSMCR (bayesian sparse MCR) to enhance the quality of resolve result.
Food for (Mathematical) Thought

Abstract The value of using manipulatives to teach mathematics is well-documented by education research. Even at the undergraduate level, concrete models can enable students to explore mathematical concepts with hands-on activities. Using food as a manipulative is a time-honored tradition in my courses and adds some extra interest and motivation for students as they learn mathematics. In this paper, I describe some successful applications of “food for thought” with examples from courses such as Precalculus, Calculus, Statistics, Geometry, and Proof-Writing.
Non invasive echographic techniques for arterial wall characterization

The authors' goal is the definition of new vascular ultrasound modalities for the detection and the characterization of vascular diseases. They propose quantitative approaches for local arterial wall lesions evaluations based on ultrasonic measurements of the wall motion dynamics. A conventional ultrasound scanner is configured to provide a very high frame rate up to 200 frames per second. The arterial segments are axially visualized and the resulting RF signals are cross-correlated from frame to frame for the extraction of wall incremental motions. Wall displacements and intraparietal strain images are reconstructed providing dynamic images sequences. Arterial dilations and wall displacements are dynamically superimposed on the grey scale images. In vitro and in vivo data have been processed in order to test and validate these new procedures. In particular, strain images acquired in vitro on arterial samples are compared with the corresponding anatomo-pathological analysis. Wall displacements measurements are confronted to a mechanical model describing arterial lesions as local defects in elastic tubes. The proposed displays are very attractive to observe the arterial wall behaviour in case of plaques or stenoses. Moreover, the obtained wall motions are in good accordance with the modelized ones. These new ultrasonic procedures dynamically describe the mechanical consequences of arterial lesions. It will probably enable physicians to evaluate vascular diseases with pertinent criteria based directly on the arterial wall state.