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2023 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2023

作者： Schumer, Alexander Nasari, Hadiseh Liu, Yuzhou G.N. Lopez-Galmiche, Gisela Leshin, Jason Lopez-Aviles, Helena E. Ding, Lei Alahmadi, Yousef Hassan, Absar U. Zhong, Qi Rotter, Stefan LiKamWa, Patrick Christodoulides, Demetrios N. Khajavikhan, Mercedeh ViennaA-1040 Austria Ming Hsieh Department of Electrical and Computer Engineering University of Southern California Los AngelesCA90089 United States CREOL The College of Optics & Photonics University of Central Florida OrlandoFL United States Center of Excellence for Telecomm Applications Joint Centers of Excellence Program King Abdul Aziz City for Science and Technology Riyadh11442 Saudi Arabia Department of Physics & Astronomy University of Southern California Los AngelesCA United States

ISBN: (纸本)9798350345995

When non-Hermitian eigenvalue surfaces form intertwined Riemann surfaces, the corresponding non-Hermitian singularities, also know as exceptional points (EPs), are located at the center of this specific topology. Various experimental platforms have recently been presented in which interesting new physics associated with these branch point singularities can be explored. In particular, it has been shown that dynamically encircling EPs may lead to a so-called chiral state transfer. The chirality in this context refers to the fact that in such an encircling protocol, the final state at the end of an EP-enclosing loop solely depends on the encircling direction (clockwise or counterclockwise), but not on the initial state. Such a chiral behavior is intrinsically linked to the state vector deviating from adiabatically following the system's eigenstates associated with the eigenvalue surfaces;instead, due to the non-Hermitian violation of the adiabatic theorem, non-adiabatic jumps let the system undergo transitions from lossy eigenstates to eigenstates with gain. Here, we present two experiments that implement concepts that go beyond this established paradigm. © 2023 IEEE.

关键词： Topology

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Human Fall Prediction and Detection Using Low Price IMU Sensor

Human Fall Prediction and Detection Using Low Price IMU Sens...

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IEEE Eurasia Conference on IOT, Communication and Engineering (ECICE)

作者： Chanasorn Nutsathaporn Sakchai Chomkokard Wiwat Wongkokua Noparit Jinuntuya Somchoke Ruengittinun Siriporn Sasimontonkul Department of Physics Metrology Program Faculty of Science Kasetsart University Bangkok Thailand Department of Computer Science Faculty of Science Kasetsart University Bangkok Thailand Faculty of Sports Science Kasetsart University Kamphaeng Saen Campus Nakhon Pathom Thailand

ISBN: (纸本)9781665482097

In this project, we develop a device to warn the elderly when they are unsteady and at a risk of falling, based on a low price IMU sensor. From our preliminary study we find that during the sway, the body vibrates violently in all frequencies. This is different from the body at stationary posture, where the vibration is small, or when a person moves in a regular manner where the body vibrates with some definite frequencies. From these results, it is possible to use the mean amplitude of the Fourier spectrum of the body acceleration to distinguish the vibration state of the body, which can be used in the warning system. We then designed the device using the low price MPU6050 sensor to measure the body acceleration. This device will be attached to the body (hip) for collecting the acceleration data. An ESP8266 board is used to collect and control the sensor operation. Another ESP8266 board is used to receive and send the data to a Raspberry Pi unit. All data transmission is performed wirelessly via ESP NOW protocol, which is a low power consumption 2.4GHz wireless communication with a data package of up to 250 bytes at a time with 100-200m transmission range, which cover the living space area of typical wearer. When the mean amplitude of Fourier spectrum is greater than the warning criteria, the Raspberry Pi will send a signal to the warning unit wirelessly through the ESP8266 board. There are 3 types of alarms in warning unit which are sound alarm, light alarm, and LCD display alarm. We have tested our system with many volunteers. The mean amplitude of Fourier spectrum in the steady, walking, and sway condition can be clearly distinguished. In all cases the state of risky from falling can be detected correctly. We are now in the process of maximizing the data sampling and analyzing time to make the falling prediction as fast as possible.

关键词： Vibrations Wireless communication Performance evaluation Protocols Power demand Measurement units Alarm systems

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Ab Initio Generalized Langevin Equation

arXiv

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arXiv 2022年

作者： Xie, Pinchen Car, Roberto Weinan, E. Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States Department of Chemistry Department of Physics Program in Applied and Computational Mathematics Princeton Institute for the Science and Technology of Materials Princeton University PrincetonNJ08544 United States AI for Science Institute Beijing China Center for Machine Learning Research School of Mathematical Sciences Peking University Beijing China

We introduce a machine learning-based approach called ab initio generalized Langevin equation (AIGLE) to model the dynamics of slow collective variables in materials and molecules. In this scheme, the parameters are learned from atomistic simulations based on ab initio quantum mechanical models. Force field, memory kernel, and noise generator are constructed in the context of the Mori-Zwanzig formalism, under the constraint of the fluctuation-dissipation theorem. Combined with deep potential molecular dynamics and electronic density functional theory, this approach opens the way to multi-scale modeling in a variety of situations. Here, we demonstrate this capability with a study of two mesoscale processes in crystalline lead titanate, namely the field-driven dynamics of a planar ferroelectric domain wall, and the dynamics of an extensive lattice of coarse-grained electric dipoles. In the first case, AIGLE extends the reach of ab initio simulations to a regime of noise-driven motions not accessible to molecular dynamics. In the second case, AIGLE deals with an extensive set of collective variables by adopting a local approximation for the memory kernel and retaining only short-range noise correlations. The scheme is computationally more efficient than molecular dynamics by several orders of magnitude, and mimics the microscopic dynamics at low frequencies where it reproduces accurately the dominant far-infrared absorption frequency. © 2022, CC BY.

关键词： Molecular dynamics

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Design and Characterization of Type-Ii Superlattice-Based Inas/Alsb/Gasb Detector Structure

SSRN

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SSRN 2024年

作者： Kızılkaya, Kürşat Öztürk, Mustafa Kemal Hoştut, Mustafa Ergün, Yüksel Özçelik, Süleyman Turkish Aerospace Fethiye District Havacılık Avenue No:17 Ankara06980 Turkey Advanced Technologies Program Graduate School of Natural and Applied Sciences Gazi University Ankara06560 Turkey Photonics Application and Research Center Gazi University Ankara06560 Turkey Physics Department of Science Faculty Gazi University Ankara06560 Turkey Physics Department of Science Faculty Eskisehir Technical University Eskisehir26470 Turkey Photonics Department of Applied Science Faculty Gazi University Ankara06560 Turkey Department of Mathematics and Science Education Faculty of Education Akdeniz University Antalya07058 Turkey

In this study, N-Structured based InAs/AlSb/GaSb Type-II Superlattice pbin type detector structures are investigated. These systems make absorption in infrared region in electromagnetic spectrum as detectors. Structural characterization of these systems is aimed. n-type GaSb is used as the substrate. InAs/AlSb/GaSb-based repetitive SL layers are formed as n-layer, i-layer, p-layer and p-contact layer from the bottom InAsSb layer to the top GaSb cap layer for 120, 300, 15 and 80 periods, respectively. Structural characterization of all layers is made by using SIMS and XRD systems analyses. The structural depth profile of the SL layers has been presented comparatively through SIMS analysis. The interfacial transitions observed in the depth profile are consistent with the designed T2SL layers. By using XRD characterization, crystal quality parameters, lattice constants and periodicity and deviation of super lattice peak from substrate are determined. Such dislocation density and strain are measured AS 7.85x107cm-2 and 6.4x10-3 nm, respectively. SEM analysis is used to examine top layer morphology and cross-section of the structure. The cross-sectional measurements allowed the observation of interfacial transitions within the SL structure. In this study, super lattice with high crystal quality is achieved and results show that T2SL detector structures are succeeded. © 2024, The Authors. All rights reserved.

关键词： III-V semiconductors

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BRAIN-TO-TEXT BENCHMARK’24: LESSONS LEARNED

arXiv

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arXiv 2024年

作者： Willett, Francis R. Li, Jingyuan Le, Trung Fan, Chaofei Chen, Mingfei Shlizerman, Eli Chen, Yue Zheng, Xin Okubo, Tatsuo S. Benster, Tyler Lee, Hyun Dong Kounga, Maxwell Buchanan, E. Kelly Zoltowski, David Linderman, Scott W. Henderson, Jaimie M. Department of Neurosurgery Stanford University United States Department of Electrical & Computer Engineering University of Washington United States Department of Computer Science Stanford University United States Department of Applied Mathematics University of Washington United States China Neurosciences Phd Program Stanford University United States Wu Tsai Neurosciences Institute Department of Statistics Stanford University United States

Speech brain-computer interfaces aim to decipher what a person is trying to say from neural activity alone, restoring communication to people with paralysis who have lost the ability to speak intelligibly. The Brain-to-Text Benchmark’24 and associated competition was created to foster the advancement of decoding algorithms that convert neural activity to text. Here, we summarize the lessons learned from the competition ending on June 1, 2024 (the top 4 entrants also presented their experiences in a recorded webinar). The largest improvements in accuracy were achieved using an ensembling approach, where the output of multiple independent decoders was merged using a fine-tuned large language model (an approach used by all 3 top entrants). Performance gains were also found by improving how the baseline recurrent neural network (RNN) model was trained, including by optimizing learning rate scheduling and by using a diphone training objective. Improving upon the model architecture itself proved more difficult, however, with attempts to use deep state space models or transformers not yet appearing to offer a benefit over the RNN baseline. The benchmark will remain open indefinitely to support further work towards increasing the accuracy of brain-to-text algorithms. © 2024, CC BY.

关键词： Recurrent neural networks

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WISH:wavefront imaging sensor with high resolution

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Light(science & Applications) 2019年第1期8卷 818-827页

作者： Yicheng Wu Manoj Kumar Sharma Ashok Veeraraghavan Department of Electrical and Computer Engineering Rice UniversityHoustonTXUSA Applied Physics Program Rice UniversityHoustonTXUSA

Wavefront sensing is the simultaneous measurement of the amplitude and phase of an incoming optical *** wavefront sensors such as Shack-Hartmann wavefront sensor(SHWFS)suffer from a fundamental tradeoff between spatial resolution and phase estimation and consequently can only achieve a resolution of a few thousand *** break this tradeoff,we present a novel computational-imaging-based technique,namely,the Wavefront Imaging Sensor with High resolution(WISH).We replace the microlens array in SHWFS with a spatial light modulator(SLM)and use a computational phase-retrieval algorithm to recover the incident *** wavefront sensor can measure highly varying optical fields at more than 10-megapixel resolution with the fine phase *** the best of our knowledge,this resolution is an order of magnitude higher than the current noninterferometric wavefront *** demonstrate the capability of WISH,we present three applications,which cover a wide range of spatial ***,we produce the diffraction-limited reconstruction for long-distance imaging by combining WISH with a large-aperture,low-quality Fresnel ***,we show the recovery of high-resolution images of objects that are obscured by ***,we show that WISH can be used as a microscope without an objective *** study suggests that the designing principle of WISH,which combines optical modulators and computational algorithms to sense high-resolution optical fields,enables improved capabilities in many existing applications while revealing entirely new,hitherto unexplored application areas.

关键词： estimation. field. resolution

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Psychological Stress Classification Using Extreme Gradient Boosting Algorithm

Psychological Stress Classification Using Extreme Gradient B...

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International Conference on Information and Communication Technology Convergence (ICTC)

作者： Maria Mahardini Sakanti Viacheslav Siniaev Aurelia Amaris Win-Jet Luo Suhartono C. Bambang Dwi Kuncoro Graduate Institute of Precision Manufacturing National Chin-Yi University of Technology Taichung Taichung Taiwan Institute of Applied Computer Science ITMO University St. Petersburg Russian Federation Department of Informatics Engineering Faculty of Computer Science Universitas Brawijaya Malang Indonesia Ph.D. Program Prospective Technology of Electrical Engineering and Computer Science National Chin-Yi University of Technology Taichung Taichung Taiwan Department of Refrigeration Air Conditioning and Energy Engineering National Chin-Yi University of Technology Taichung Taiwan

ISBN: (数字)9798350364637

ISBN: (纸本)9798350364644

Stress, as a reaction to threatening situations, can raise heart rate and result in serious conditions that might cause significant damage or even be life-threatening. Traditional methods for evaluating stress, which rely on subjective self-reporting and clinical assessments, often suffer from biases and inconsistencies. Artificial intelligence models have been explored to predict stress levels more accurately. This paper investigates the application of Extreme Gradient Boosting in classifying psychological stress using the WESAD dataset, which includes parameters such as acceleration, electrocardiogram, electromyography, electrodermal activity, temperature, and respiration. The dataset was balanced and sampled to create a manageable subset for experimental. Extreme Gradient Boosting was chosen for its efficiency and scalability in handling complex datasets. The model was trained and validated, achieving a 95% accuracy in predicting stress levels. This study highlights the potential of integrating Extreme Gradient Boosting models into wearable devices for real-time stress monitoring. Future work involves optimizing the model to utilize fewer sensors without decreasing accuracy, ensuring it can be integrated into portable/wearable systems using tiny microcontrollers.

关键词： Accuracy Microcontrollers Psychology Human factors Predictive models Boosting Prediction algorithms Real-time systems Sensors Wearable devices

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The challenges of measuring spin Seebeck noise

arXiv

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arXiv 2023年

作者： Luo, Renjie Zhao, Xuanhan Legvold, Tanner J. Chen, Liyang Liu, Changjiang Hong, Deshun Bhattacharya, Anand Natelson, Douglas Department of Physics and Astronomy Rice University HoustonTX77005 United States Applied Physics Program Smalley-Curl Institute Rice University HoustonTX77005 United States Materials Science Division Argonne National Laboratory LemontIL60439 United States Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States

Just as electronic shot noise in driven conductors results from the granularity of charge and the statistical variation in the arrival times of charge carriers, there are predictions for fundamental noise in magnon currents due to angular momentum being carried by discrete excitations. The inverse spin Hall effect as a transduction mechanism to convert spin current into charge current raises the prospect of experimental investigations of such magnon shot noise. Spin Seebeck effect measurements have demonstrated the electrical detection of thermally driven magnon currents and have been suggested as an avenue for accessing spin current fluctuations. Using spin Seebeck structures made from yttrium iron garnet on gadolinium gallium garnet, we demonstrate the technical challenges inherent in such noise measurements. While there is a small increase in voltage noise in the inverse spin Hall detector at low temperatures associated with adding a magnetic field, the dependence on field orientation implies that this is not due to magnon shot noise. We describe theoretical predictions for the expected magnitude of magnon shot noise, highlighting ambiguities that exist. Further, we show that magnon shot noise detection through the standard inverse spin Hall approach is likely impossible due to geometric factors. Implications for future attempts to measure magnon shot noise are discussed. Copyright © 2023, The Authors. All rights reserved.

关键词： Shot noise

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Impact of Quantum Well Thickness on Efficiency Loss in InGaN/GaN LEDs: Challenges for Thin-Well Designs

arXiv

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arXiv 2025年

作者： Li, Xuefeng Pant, Nick Rahman, Sheikh Ifatur Armitage, Rob Rajan, Siddharth Kioupakis, Emmanouil Feezell, Daniel University of New Mexico AlbuquerqueNM87106 United States Department of Materials Science & Engineering University of Michigan Ann ArborMI48109 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43210 United States Lumileds LLC San JoseCA95131 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States

We investigate the impact of quantum well (QW) thickness on efficiency loss in c-plane InGaN/GaN LEDs using a small-signal electroluminescence (SSEL) technique. Multiple mechanisms related to efficiency loss are independently examined, including injection efficiency, carrier density vs. current density relationship, phase space filling (PSF), quantum confined stark effect (QCSE), and Coulomb enhancement. An optimal QW thickness of around 2.7 nm in these InGaN/GaN LEDs was determined for quantum wells having constant In composition. Despite better control of deep-level defects and lower carrier density at a given current density, LEDs with thin QWs still suffer from an imbalance of enhancement effects on the radiative and intrinsic Auger-Meitner recombination coefficients. The imbalance of enhancement effects results in a decline in internal quantum efficiency (IQE) and radiative efficiency with decreasing QW thickness at low current density in LEDs with QW thicknesses below 2.7 nm. We also investigate how LED modulation bandwidth varies with quantum well thickness, identifying the key trends and their implications for device performance. Copyright © 2025, The Authors. All rights reserved.

关键词： Semiconductor quantum wells

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The Utilization of Padding Scheme on Convolutional Neural Network for Cervical Cell Images Classification

The Utilization of Padding Scheme on Convolutional Neural Ne...

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2020 International Conference on computer Engineering, Network, and Intelligent Multimedia, CENIM 2020

作者： Haryanto, Toto Sitanggang, Imas Sukaesih Agmalaro, Muhammad Ashyar Rulaningtyas, Riries IPB University Computer Science Department Bogor Indonesia Universitas Airlangga Biomedical Engineering Program Department of Physics Surabaya Indonesia

ISBN: (纸本)9781728182834

Cervical cancer identification through pap-smear images analysis is a challenge for medicians, especially in distinguishing cells, between the normal and abnormal one. This study aims to create the classification model of Cervical Cell Images using the Convolutional Neural Network (CNN) algorithm. The dataset used is the image dataset SIPaKMeD. The CNN algorithm was implemented using the AlexNet architecture with and non-padding scheme. Padding is included in the experiments by adding the pixel 0 on the original images to improve the accuracy of the model. The experimental results show that using the utilization padding scheme on the AlexNet architecture can increase the accuracy of the model slightly significantly from 84.88% to 87.32%. © 2020 IEEE.

关键词： Convolutional neural networks

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