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Multi-wavelength edge detection based on nonlocal multilayer GaAs–AlAs thin films

Optics Letters 2025年第12期50卷 3856-3859页

作者： Sina Mohammadi Matthew Markowitz Francesco Monticone Mohammad Ali Miri Maria Tamargo Ph.D. Program in Physics The Graduate Center of the City University of New York New York New York 10016 USA Department of Physics Queens College of the City University of New York Queens New York 11367 USA School of Electrical and Computer Engineering Cornell University Ithaca New York 14853 USA Department of Chemistry The City College of New York New York New York 10031 USA

We demonstrate a compact multilayer GaAs–AlAs structure for passive optical edge detection at multiple wavelengths. Through the inverse design of the layer thicknesses, this structure manipulates spatial frequency components of an incoming wavefront, selectively reflecting high-frequency features while suppressing low-frequency intensity variations. Simulations reveal a reflectance transition from minimal to near-total as a function of numerical aperture, a property leveraged for enhancing edge contrast in optical imaging. For the first time, to our knowledge, we utilize molecular beam epitaxy (MBE) to fabricate edge detection devices, ensuring structural fidelity. Material characterization confirms high-quality interfaces, precise thickness control, and excellent uniformity, validating the suitability of MBE for this application. Experimental angle-resolved reflectance measurements closely align with theoretical predictions, demonstrating the feasibility of this approach for real-time, hardware-based optical image processing. The proposed design automatically works for at least two wavelengths and can be readily extended to operate at multiple wavelengths simultaneously. This work opens new possibilities for employing multilayer interference structures in high-performance optical imaging and real-time signal processing.

关键词： Digital image processing Edge detection Inverse design Optical imaging Signal processing Thin films

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Automatic facial expression recognition in an image sequence using conditional random field

Automatic facial expression recognition in an image sequence...

引用

International Symposium on Computational Intelligence and Informatics

作者： Mohamad Roshanzamir Mahdi Roshanzamir Abdolreza Mirzaei Mohammad Tayarani Darbandy Afshin Shoeibi Roohallah Alizadehsani Fahime Khozeimeh Abbas Khosravi Department of Computer Engineering Fasa University Fasa Iran Department of Electrical and Computer Engineering University of Tabriz Tabriz Iran Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan Iran School of Architecture Islamic Azad University Taft Taft Iran Internship in Health Data Analytics Program AI-enabled Processes (AIP) Research Centre Macquarie University Sydney Australia Institute for Intelligent Systems Research and Innovation (IISRI) Deakin University Victoria Australia

ISBN: (纸本)9798350398830

Facial expression recognition is one of the fields that nowadays has attracted the attention of many researchers. It is possible to automate facial expression recognition using artificial intelligence methods. This will be of great help to researchers, especially in areas such as psychology. Automatic facial recognition can be derived from a static image of facial expression, but a better and more efficient way to do this is through a sequence of images. In this paper, a new method is proposed to automatically detect facial expressions from a sequence of images. Each sequence of facial images begins with a face neutral state and ends with one of the six main emotions. Motion vectors are extracted from the sequence using optical flow algorithm. These vectors are then used to train the conditional random field and finally to automatically determine the emotion. In this paper, in addition to the basic conditional random field, the hidden dynamic conditional random field is also investigated. Additionally, the effect of changing some parameters of these algorithms such as different optimization methods has been investigated. Given that a facial expression is recognized during a sequence of images, random field-based methods can be used for efficient classification of facial expressions reaching accuracy (more than 90%) competitive with the best existing methods for facial expression recognition.

关键词： Image recognition Mechatronics Face recognition Heuristic algorithms Psychology Optimization methods Feature extraction

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Photon avalanche-driven multicolor emission: yttrium vanadate upconversion phosphors for optical thermometry, forensics, and healing light applications

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Chemical engineering Journal 2025年 516卷

作者： Pavitra, Eluri Antony, Lintymol Park, Jin Young Hwang, Seung Kyu Lee, Jeong-Hwan Chandra, Gogineni Rajesh Basaveswara Rao, M.V. Raju, Ganji Seeta Rama Han, Young-Kyu Huh, Yun Suk NanoBio High-Tech Materials Research Center Department of Biological Sciences and Bioengineering Inha University Incheon22212 Korea Republic of 3D Convergence Center Inha University Incheon22212 Korea Republic of Department of Energy and Materials Engineering Dongguk University-Seoul Seoul04620 Korea Republic of Department of Electrical Electronics and Software Engineering Pukyong National University Yongdang Campus Busan48547 Korea Republic of Department of Materials Science and Engineering Inha University Incheon22212 Korea Republic of Program in Semiconductor Convergence Inha University Incheon22212 Korea Republic of Department of Computer Science and Engineering Vignan's Lara Institute of Technology & Science Andhra Pradesh Guntur India Department of Chemistry Krishna University Andhra Pradesh Machillipatnam521001 India

The exploration of photon upconversion has led to the development of multifunctional lanthanide-based materials, particularly through the mechanism of photon avalanche, marking a transformative advancement in material science. In this study, yttrium vanadate upconversion nanocrystalline phosphors (UCNCPs) activated by Ho3+/Er3+/Tm3+/Yb3+ ions are reported. These UCNCPs demonstrate a remarkable ability in the photon avalanche, offering highly intense and tunable emissions across the visible spectrum at room temperature under low excitation power of 980 nm laser. The average number of photons involved in the UC process at threshold pump power, highlighting the intricate interplay of cross-relaxation and energy transfer loops in avalanche mechanism. Notably, these UCNCPs have shown exceptional temperature sensing capabilities, where non-thermally coupled levels of the Ho3+ and Tm3+ ions provide higher relative sensitivity and accuracy than thermally coupled levels of Er3+ ions. The versatility of these UCNCPs is further established by their application in solid-state lighting, where they can produce vibrant red, green, blue, and warm-white light, and in security, serving as multi-level anti-counterfeiting inks that respond to 980 nm laser illumination. These developments not only pave the way for more energy-efficient lighting solutions but also offer new avenues for enhancing the security of valuable items. The temperature sensing capabilities of these phosphors add another layer of functionality, making them ideal for high-tech applications ranging from medical diagnostics to environmental monitoring. © 2025 Elsevier B.V.

关键词： Phosphors

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CRISPR-GPT: An LLM Agent for Automated Design of Gene-Editing Experiments

arXiv

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arXiv 2024年

作者： Huang, Kaixuan Qu, Yuanhao Cousins, Henry Johnson, William A. Yin, Di Shah, Mihir Zhou, Denny Altman, Russ Wang, Mengdi Cong, Le Department of Electrical and Computer Engineering Princeton University United States Department of Pathology Department of Genetics Stanford University School of Medicine United States Cancer Biology Program Stanford University School of Medicine United States Department of Medicine Stanford University School of Medicine United States Medical Scientist Training Program Stanford University School of Medicine United States Google DeepMind United Kingdom Department of Bioengineering Department of Genetics Stanford University United States Center for Statistics and Machine Learning Princeton University United States

The introduction of genome engineering technology has transformed biomedical research, making it possible to make precise changes to genetic information. However, creating an efficient gene-editing system requires a deep understanding of CRISPR technology, and the complex experimental systems under investigation. While Large Language Models (LLMs) have shown promise in various tasks, they often lack specific knowledge and struggle to accurately solve biological design problems. In this work, we introduce CRISPR-GPT, an LLM agent augmented with domain knowledge and external tools to automate and enhance the design process of CRISPR-based gene-editing experiments. CRISPR-GPT leverages the reasoning ability of LLMs to facilitate the process of selecting CRISPR systems, designing guide RNAs, recommending cellular delivery methods, drafting protocols, and designing validation experiments to confirm editing outcomes. We showcase the potential of CRISPR-GPT for assisting non-expert researchers with gene-editing experiments from scratch and validate the agent’s effectiveness in a real-world use case. Furthermore, we explore the ethical and regulatory considerations associated with automated gene-editing design, highlighting the need for responsible and transparent use of these tools. Our work aims to bridge the gap between beginner biological researchers and CRISPR genome engineering techniques, and demonstrate the potential of LLM agents in facilitating complex biological discovery tasks. Copyright © 2024, The Authors. All rights reserved.

关键词： Genes

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Understanding YTHDF2-mediated mRNA Degradation By m6A-BERT-Deg

arXiv

引用

arXiv 2024年

作者： Zhang, Ting-He Jo, Sumin Zhang, Michelle Wang, Kai Gao, Shou-Jiang Huang, Yufei Cancer Virology Program UPMC Hillman Cancer Center University of Pittsburgh School of Medicine PittsburghPA United States Department of Medicine University of Pittsburgh School of Medicine PittsburghPA United States Department of Electrical and Computer Engineering Swanson School of Engineering University of Pittsburgh PittsburghPA United States Department of Electrical and Computer Engineering The University of Texas at San Antonio San AntonioTX78249 United States Raymond G. Perelman Center for Cellular and Molecular Therapeutics Children’s Hospital of Philadelphia PhiladelphiaPA19104 United States Department of Pathology and Laboratory Medicine Perelman School of Medicine University of Pennsylvania PhiladelphiaPA19104 United States Department of Microbiology and Molecular Genetics University of Pittsburgh School of Medicine PittsburghPA United States

N6-methyladenosine (m6A) is the most abundant mRNA modification within mammalian cells, holding pivotal significance in the regulation of mRNA stability, translation, and splicing. Furthermore, it plays a critical role in the regulation of RNA degradation by primarily recruiting the YTHDF2 reader protein. However, the selective regulation of mRNA decay of the m6A-methylated mRNA through YTHDF2 binding is poorly understood. To improve our understanding, we developed m6A-BERT-Deg, a BERT model adapted for predicting YTHDF2-mediated degradation of m6A-methylated mRNAs. We meticulously assembled a high-quality training dataset by integrating multiple data sources for the HeLa cell line. To overcome the limitation of small training samples, we employed a pre-training-fine-tuning strategy by first performing a self-supervised pre-training of the model on 427,760 unlabeled m6A site sequences. The test results demonstrated the importance of this pre-training strategy in enabling m6A-BERT-Deg to outperform other benchmark models. We further conducted a comprehensive model interpretation and revealed a surprising finding that the presence of co-factors in proximity to m6A sites may disrupt YTHDF2-mediated mRNA degradation, subsequently enhancing mRNA stability. We also extended our analyses to the HEK293 cell line, shedding light on the context-dependent YTHDF2-mediated mRNA degradation. © 2024, CC BY.

关键词： Mammals

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Performance Analysis and Optimization for Jammer-Aided Multi-Antenna UAV Covert Communication

arXiv

引用

arXiv 2022年

作者： Du, Hongyang Niyato, Dusit Xie, Yuan-Ai Cheng, Yanyu Kang, Jiawen Kim, Dong In The School of Computer Science and Engineering Energy Research Institute @ NTU Interdisciplinary Graduate Program Nanyang Technological University Singapore The School of Computer Science and Engineering Nanyang Technological University Singapore The Institute of Electrical Engineering Yanshan University Qinhuangdao066004 China Alibaba-NTU Singapore Joint Research Institute Nanyang Technological University Singapore639798 Singapore The Department of Electrical and Computer Engineering Sungkyunkwan University Suwon16419 Korea Republic of

Unmanned aerial vehicles (UAVs) have attracted a lot of research attention because of their high mobility and low cost in serving as temporary aerial base stations (BSs) and providing high data rates for next-generation communication networks. To protect user privacy while avoiding detection by a warden, we investigate a jammer-aided UAV covert communication system, which aims to maximize the user's covert rate with optimized transmit and jamming power. The UAV is equipped with multi-antennas to serve multi-users simultaneously and enhance the Quality of Service. By considering the general composite fading and shadowing channel models, we derive the exact probability density (PDF) and cumulative distribution functions (CDF) of the signal-to-interference-plus-noise ratio (SINR). The obtained PDF and CDF are used to derive the closed-form expressions for detection error probability and covert rate. Furthermore, the covert rate maximization problem is formulated as a Nash bargaining game, and the Nash bargaining solution (NBS) is introduced to investigate the negotiation among users. To solve the NBS, we propose two algorithms, i.e., particle swarm optimization-based and joint two-stage power allocation algorithms, to achieve covertness and high data rates under the warden's optimal detection threshold. All formulated problems are proven to be convex, and the complexity is analyzed. The numerical results are presented to verify the theoretical performance analysis and show the effectiveness and success of achieving the covert communication of our algorithms. © 2022, CC BY.

关键词： Unmanned aerial vehicles (UAV)

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Nernst-Ettingshausen effect in thin Pt and W films at low temperatures

arXiv

引用

arXiv 2023年

作者： Luo, Renjie Legvold, Tanner J. Chen, Liyang Natelson, Douglas Department of Physics and Astronomy Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Electrical and Computer Engineering Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States

As spin caloritronic measurements become increasingly common techniques for characterizing material properties, it is important to quantify potentially confounding effects. We report measurements of the Nernst-Ettingshausen response from room temperature to 5 K in thin film wires of Pt and W, metals commonly used as inverse spin Hall detectors in spin Seebeck characterization. Johnson-Nyquist noise thermometry is used to assess the temperature change of the metals with heater power at low temperatures, and the thermal path is analyzed via finite-element modeling. The Nernst-Ettingshausen response of W is found to be approximately temperature-independent, while the response of Pt increases at low temperatures. These results are discussed in the context of theoretical expectations and the possible role of magnetic impurities in Pt. Copyright © 2023, The Authors. All rights reserved.

关键词： Inverse problems

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Mechatronic Design of an Amphibious Drone

Mechatronic Design of an Amphibious Drone

引用

International Conference on Autonomous Robots and Agents, ICARA

作者： Nikolaos Evangeliou Dimitris Chaikalis Nikolaos Giakoumidis Anthony Tzes Electrical Engineering Program New York University Abu Dhabi United Arab Emirates Electrical & Computer Engineering Department New York University Brooklyn NY USA Kinesis Lab Core Technology Platform New York University Abu Dhabi United Arab Emirates Center for Artificial Intelligence and Robotics New York University Abu Dhabi United Arab Emirates

This paper is concerned with the mechatronic design of a tricopter drone which can move as a ground vehicle and/or as a vessel. The tricopter has three pairs of coaxial rotors and is capable of providing 100N of thrust with a 15 minute flight time using an 8S LiPo 12.5Ah battery. Three waterproof motors are attached to an isosceles triangular omniwheel configuration for operating as a ground vehicle after landing. The customized wheels allow the vehicle to move with a linear velocity up to 2 m/sec at a tilt slope up to 20°. Two submersible parallel water thrusters provide 24N collective force leading to a maximum vessel velocity of 1 m/s and a turn radius of 1.5 m. The design alternatives are highlighted and prioritized according to their weight while the overall amphibious drone is shown in several flight/omniwheel vehicle/vessel modes.

关键词： Mechatronics Navigation Force Wheels Rotors Prototypes Land vehicles

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In vivo Detection of NO using Photonic Microring Resonators

In vivo Detection of NO using Photonic Microring Resonators

引用

Conference on Lasers and Electro-Optics (CLEO)

作者： Sakib Hassan Xuan Zhao Christian C. Schreib Guillaume Duret Omid Veiseh Jacob T. Robinson Electrical & Computer Engineering Rice University Houston USA Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston USA Department of Bioengineering Rice University Houston USA

Here we show how photonic microring resonators enable real-time detection of Nitric Oxide (NO) in vivo, which is critical for physiological monitoring particularly during the wound healing process.

ISBN: (数字)9781957171050

ISBN: (纸本)9781665466660

Here we show how photonic microring resonators enable real-time detection of Nitric Oxide (NO) in vivo, which is critical for physiological monitoring particularly during the wound healing process.

关键词： Integrated optics In vivo Optical resonators Wounds Laser modes Lab-on-a-chip Real-time systems

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Machine Learning Based Classification of Micro-Doppler Radar Responses of Hands and Harmonically-Tagged Held Objects

TechRxiv

引用

TechRxiv 2022年

作者： Nourshamsi, Neda Maaz, Mohammad Jafari, Amir Hossein Nanzer, Jeffrey A. Department of Electrical and Computer Engineering Michigan State University East LansingMI48824 United States Data Science program The George Washington University WashingtonDC20052 United States

We explore the differentiability of the micro-Doppler signal responses of human hand motion and held objects using harmonic radar and harmonic tags. When observing moving hands and objects tagged with harmonic radio-frequency tags, the harmonic radar detects motion (Doppler) responses at the fundamental frequency (scattered from the hand) and at the harmonic frequency (generated by the tag). In homodyne harmonic radars, both frequency responses manifest at baseband. In this work we explore the feasibility of differentiating the micro-Doppler and harmonic micro-Doppler baseband responses using machine learning based classification. For this purpose, three different classification algorithms in parallel with Adam optimization have been deployed. Results are presented in terms of confusion matrix and receiver operating curve (ROC). Overall, Convolution neural network (CNN) provides more accurate performance compared to the other algorithms, demonstrating the first step in classifications of human and hand-held objects. This work provides a framework for future research in harmonic micro-Doppler signal classification. © 2022-11-13, CC BY.

关键词： Deep neural networks

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