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arXiv 2024年

作者： Li, Tao Bian, Zilin Lei, Haozhe Zuo, Fan Yang, Ya-Ting Zhu, Quanyan Li, Zhenning Ozbay, Kaan Department of Electrical and Computer Engineering New York University United States Department of Civil and Urban Engineering New York University United States State Key Laboratory of Internet of Things for Smart City University of Macau China

In urban traffic management, the primary challenge of dynamically and efficiently monitoring traffic conditions is compounded by the insufficient utilization of thousands of surveillance cameras along the intelligent transportation system. This paper introduces the multi-level Traffic-responsive Tilt Camera surveillance system (TTC-X), a novel framework designed for dynamic and efficient monitoring and management of traffic in urban networks. By leveraging widely deployed pan-tilt-cameras (PTCs), TTC-X overcomes the limitations of a fixed field of view in traditional surveillance systems by providing mobilized and 360-degree coverage. The innovation of TTC-X lies in the integration of advanced machine learning modules, including a detector-predictor-controller structure, with a novel Predictive Correlated Online Learning (PiCOL) methodology and the Spatial-Temporal Graph Predictor (STGP) for real-time traffic estimation and PTC control. The TTC-X is tested and evaluated under three experimental scenarios (e.g., maximum traffic flow capture, dynamic route planning, traffic state estimation) based on a simulation environment calibrated using real-world traffic data in Brooklyn, New York. The experimental results showed that TTC-X captured over 60% total number of vehicles at the network level, dynamically adjusted its route recommendation in reaction to unexpected full-lane closure events, and reconstructed link-level traffic states with best MAE less than 1.25 vehicle/hour. Demonstrating scalability, cost-efficiency, and adaptability, TTC-X emerges as a powerful solution for urban traffic management in both cyber-physical and real-world environments. © 2024, CC BY.

关键词： Urban transportation

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Structural RC computer aided intelligent analysis and computational performance via experimental investigations

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Structural engineering and Mechanics 2024年第3期90卷 253-261页

作者： Huang, Y.C. Lulios, TuMuli Chang, Chu-Ho Noor, M. Nasir Shao, Jen-Chung Chiu, Chien-Liang Lee, Tsair-Fwu Wang, Renata Information Technology Faculty Duy Tân University 254 Nguyen Van Linh Danang Viet Nam Princess Margaret Hospital Funafuti Island Private Mail Bag Tuvalu College of Electrical Engineering and Computer Science National Kaohsiung University of Science and Technology Kaohsiung Taiwan College of Maritime National Kaohsiung University of Science and Technology Kaohsiung Taiwan Department of Electronic Engineering National Kaohsiung University of Science and Technology Kaohsiung Taiwan Medical Physics and Informatics Laboratory of Electronics Engineering National Kaohsiung University of Science and Technology Kaohsiung Taiwan Information and Research Center of China 1/9 Road: 2 Block: D Section: 15 Dhaka1216 Bangladesh

This research explores a new finite element model for the free vibration analysis of bi-directional functionally graded (BDFG) beams. The model is based on an efficient higher-order shear deformation beam theory that incorporates a trigonometric warping function for both transverse shear deformation and stress to guarantee traction-free boundary conditions without the necessity of shear correction factors. The proposed two-node beam element has three degrees of freedom per node, and the inter-element continuity is retained using both C1 and C0 continuities for kinematics variables. In addition, the mechanical properties of the (BDFG) beam vary gradually and smoothly in both the in-plane and out-of-plane beam’s directions according to an exponential power-law distribution. The highly elevated performance of the developed model is shown by comparing it to conceptual frameworks and solution procedures. Detailed numerical investigations are also conducted to examine the impact of boundary conditions, the bi-directional gradient indices, and the slenderness ratio on the free vibration response of BDFG beams. The suggested finite element beam model is an excellent potential tool for the design and the mechanical behavior estimation of BDFG structures. © 2024 Techno-Press, Ltd.

关键词： Boundary conditions

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Holographic Back-Projection Method for Calibration of Fully Digital Polarimetric Phased Array Radar

IEEE Transactions on Radar Systems

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IEEE Transactions on Radar Systems 2023年 1卷 295-307页

作者： David Schvartzman José D. Díaz Díaz Duŝan Zrnić Matthew Herndon Mark B. Yeary Robert D. Palmer Advanced Radar Research Center and the School of Meteorology The University of Oklahoma Norman OK USA Johns Hopkins University Applied Physics Laboratory Laurel MD USA National Oceanic and Atmospheric Administration (NOAA)/OAR/National Severe Storms Laboratory Advanced Radar Research Center School of Meteorology and the School of Electrical and Computer Engineering The University of Oklahoma Norman OK USA Advanced Radar Research Center and the School of Electrical and Computer Engineering The University of Oklahoma Norman OK USA

Phased Array Radar (PAR) technology is rapidly rising as a candidate for future weather radars because it can provide focused, high-quality meteorological observations. Due to the need for precise measurements of polarimetric weather variables, it is desired that the radar simultaneously transmits and receives linearly polarized horizontal (H) and vertical (V) fields through beams that are well matched in gain and shape at every pointing direction. These scanning characteristics are difficult to achieve, especially with current methods such as the “park and probe” calibration, because the radiation patterns of PAR antennas are inherently dependent on their pointing direction. Thus, polarimetric array calibration is critical to produce matched H/V copolar antenna patterns. In this article, we present a polarimetric antenna calibration procedure for the fully-digital PARs based on the holographic back-projection of electric fields. The fully digital S-band Horus radar is used to implement and evaluate the proposed calibration method. First, near-field measurements of a fully active Horus antenna panel are back-projected onto the plane of the array to derive the copolar magnitude and phase of the H/V fields radiated by each antenna element. Then, digital calibration parameters are produced from back-projected fields to compensate for excitation differences and produce uniform radiation at the plane of the array. The performance of the back-projection calibration method is evaluated for broadside and for electronically scanned angles and compared to the more conventional park and probe calibration method. A robustness analysis is conducted using simulations to evaluate the impact of excitation amplitude and phase errors that could result from practical near-field environments and amplifier performance degradation. Preliminary results show that through precise digital calibration based on back-projected fields, beam matching can be significantly improved to achieve the d

关键词： Radar Calibration Radar polarimetry Meteorological radar Antenna measurements Phased arrays Radar antennas

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Integrated Photonic Platform for Low Noise Microwave Generation

Integrated Photonic Platform for Low Noise Microwave Generat...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Igor Kudelin William Groman Qing-Xin Ji Joel Guo Megan Kelleher Dahyeon Lee Takuma Nakamura Charles A. McLemore Pedram Shirmohammadi Samin Hanifi Haotian Cheng Naijun Jin Lue Wu Samuel Halladay Yizhi Luo Zhaowei Dai Warren Jin Junwu Bai Yifan Liu Wei Zhang Chao Xiang Lin Chang Vladimir Iltchenko Owen Miller Andrey Matsko Steven M. Bowers Peter T. Rakich Joe Campbell John Bowers Kerry Vahala Franklyn Quinlan Scott A. Diddams Department of Physics University of Colorado Boulder Colorado USA Time and Frequency Division National Institute of Standards and Technology Boulder Colorado USA T.J. Watson Laboratory of Applied Physics California Institute of Technology Pasadena California USA Department of Electrical and Computer Engineering University of California Santa Barbara California USA Electrical and Computer Engineering University of Virginia Charlottesville Virginia USA Department of Applied Physics Yale University New Haven Connecticut USA Jet Propulsion Laboratory California Institute of Technology Pasadena California USA Department of Electrical Computer and Energy Engineering University of Colorado Boulder Colorado USA

Using integrated photonic chip components for ‘2-point’ optical frequency division, we generate a 20 GHz microwave signal with phase noise of -135 dBc/Hz at 10 kHz offset.

ISBN: (纸本)9798350369311

Using integrated photonic chip components for ‘2-point’ optical frequency division, we generate a 20 GHz microwave signal with phase noise of -135 dBc/Hz at 10 kHz offset.

关键词： Phase noise Integrated optics Laser noise Masers Frequency conversion Microwave generation Optical noise Microwave photonics Optical devices Electro-optical waveguides

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An RF Direction Finding Payload for UAVs with Deep Learning Direction Prediction Via Resnet

An RF Direction Finding Payload for UAVs with Deep Learning ...

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International Conference on Unmanned Aircraft Systems (ICUAS)

作者： Andrew Willis Braden Feshami Srini Vasan Jimmy Touma Electrical and Computer Engineering University of North Carolina at Charlotte Charlotte NC USA Vulcan Ventura LLC. San Jose CA USA Air Force Research Laboratory Eglin AFB FL USA

ISBN: (数字)9798331513283

ISBN: (纸本)9798331513290

This article describes an RF Direction Finding (DF) payload developed for UAV systems. DF payloads sense RF signals using an antenna array and process the received signals at each antenna location to estimate the number of transmitting RF sources and their bearing relative to the payload. This article uses an open source Software Defined Radio (SDR) known as the KrakenSDR which senses transmitted RF data with (5) antennas. A new deep learning architecture is proposed for estimating the azimuthal Direction of Arrival (DoA) of RF signals from the sensed KrakenSDR antenna data. The recent availability of the compact and comparatively lightweight KrakenSDR hardware for DF applications make academic investigation of this sensor for UAS possible. DF payloads are used in a wide variety of important applications including search-and-rescue, signal intelligence, RF source geolocation, spectrum monitoring, spectrum enforcement and disaster management contexts. This article describes results for a new DoA estimation algorithm and includes discussion on integration challenges, mechanical and electromagnetic design considerations and the payload Size Weight and Power-Cost (SWaP-C) metrics using the KrakenSDR hardware.

关键词： Radio frequency Direction-of-arrival estimation Transmitting antennas RF signals Receiving antennas Estimation Directive antennas Hardware Payloads Antenna arrays

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Ga2O3Heterojunction PN Diodes with Suppressed Background Carrier Concentration for Improved Breakdown Voltage

Ga2O3Heterojunction PN Diodes with Suppressed Background Car...

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2023 Device Research Conference, DRC 2023

作者： Dong, Pengfei Wang, Chenlu Yan, Qinglong Wang, Yingming Wang, Jian Alghamdi, Sami Liu, Zhihong Zhang, Jincheng Zhou, Hong Hao, Yue School of Microelectronics Xidian University State Key Discipline Laboratory of Wide Bandgap Semiconductor Technology Xi'an710071 China The 46th Research Institute China Electronics Technology Group Corporation Key Laboratory of Advanced Semiconductor Materials of Cetc Tianjin30022061005 China King Abdulaziz University Electrical and Computer Engineering Department Jeddah21589 Saudi Arabia

ISBN: (纸本)9798350323108

In this paper, we show that by suppressing the background carrier concentration, the breakdown voltage (BV) of Ga2O3 heterojunction PN diode (HJ-PND) can be essentially enhanced. Meanwhile, through combing with high-level hole injection induced conductivity modulation effect, the specific on-resistance (Ron, sp) can be significantly reduced. Even without a carefully designed edge termination, a high power figure of merit (P-\text{FOM}=\text{BV}^{2}/\mathrm{R}{\text{on},\text{sp}}) of (3.75\ \text{kV})^{2}/(2.5\ \mathrm{m}\Omega\cdot \text{cm}^{2})=5.6\ \text{GW}/\text{cm}^{2} can be achieved. Ga2O3 HJ PN diodes with suppressed background carrier concentration for BV enhancement and high-level hole injection for Ron, sp reduction verify their great promise for future high voltage and high power applications. © 2023 IEEE.

关键词： Diodes

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MCMC-Based Sparse Bayesian Learning for Channel Estimation Using Gaussian Mixture Models

MCMC-Based Sparse Bayesian Learning for Channel Estimation U...

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2025 IEEE Wireless Communications and Networking Conference, WCNC 2025

作者： Fan, Xiaotian Zhou, Xingyu Ye, Hao Liang, Le Jin, Shi University of California Department of Electrical and Computer Engineering Santa CruzCA95064 United States Southeast University National Mobile Communications Research Laboratory Nanjing China Purple Mountain Laboratories Nanjing China

ISBN: (纸本)9798350368369

This paper investigates the downlink channel estimation problem for frequency division duplex (FDD) multi-user massive multiple-input multiple-output (MIMO) systems. We model this problem within the sparse Bayesian learning (SBL) framework, where all unknowns are treated as random variables. Due to limited scattering at the base station, the channel exhibits sparsity in the angular domain. By introducing Gaussian mixture priors to characterize the user equipment internal sparsity and partially shared sparsity, we develop a Markov chain Monte Carlo (MCMC) method to implement Bayesian inference and accurately estimate all random variables in the model, including the channel matrix. Experimental results demonstrate that the MCMC-based SBL channel estimation algorithm outperforms existing approaches by over 5 dB in multi-user scenarios while reducing pilot overhead. © 2025 IEEE.

关键词： Markov chains

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Dielectric Rod Antenna Array with Planar Folded Slot Antenna Excitation

IEEE Open Journal of Antennas and Propagation

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IEEE Open Journal of Antennas and Propagation 2021年 2卷 664-673页

作者： Saffold, Gabriel L. Weller, Thomas M. Antenna Systems Division Sensors and Electromagnetic Applications Laboratory Georgia Tech Research Institute AtlantaGA30080 United States School of Electrical Engineering and Computer Science Oregon State University CorvallisOR97331 United States

A dielectric rod antenna array fed by slot antenna radiators without the use of metallic waveguide is presented here. Communication systems, especially those related to 5G, are moving up into mm-wave bands where metal losses can become significant and many traditional fabrication and manufacturing techniques become more difficult. Dielectric rod antennas (DRA) are entirely made of dielectric and may be injection-molded or 3D-printed as solid rods, layered rods, or tubes. While the normal approach to feeding DRAs involves some version of metallic waveguide, we show here that the DRA may be integrated with a planar radiator feed and used effectively in an array configuration. The array demonstrated is a 2 × 2 array designed for operation at 15 GHz. Each DRA is 6 λ long. The array is fabricated on a 100 mm × 100 mm substrate with 52 mm separation between elements. The array radiation efficiency is 80% for an array gain of 19 dBi. © 2020 IEEE.

关键词： Radiators

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Optimal Sensor Placement for Full-Set TDOA Localization Accounting for Sensor Location Errors

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IEEE Transactions on Aerospace and Electronic Systems 2025年

作者： Zhang, Chengjie Han, Xinyang Kong, He Ho, K.C. Southern University of Science and Technology Shenzhen Key Laboratory of Control Theory and Intelligent Systems Guangdong Provincial Key Laboratory of Fully Actuated System Control Theory and Technology Shenzhen518055 China University of Missouri Electrical Engineering and Computer Science Department ColumbiaMO65211 United States

The positioning accuracy of a signal source is influenced by where the sensors are deployed. Studies in the literature for the optimal sensor placement (OSP) of localization often ignore the presence of sensor position errors. In practice, however, it is impossible to place the sensors precisely at the desired locations. This work designs OSP by accounting for the presence of Gaussian sensor position errors that are independent and identically distributed (IID), with the full set of Time Difference of Arrival measurements corrupted by Gaussian IID noise. The criterion is the A-optimality equal to the trace of the source position Cramer-Rao Bound (CRB). We show that the presence of sensor position errors introduces a multiplication factor to the same criterion for the case without sensor position errors. The latter factor is dependent on the ratio of the sensor position error power to the range difference noise power but independent of the sensor positions, implying that the A-optimality OSP in the presence of sensor position errors is the same as in the absence. To our knowledge, this is the first time such results have been derived. Simulation studies validate the derived OSP, show the minimal OSP performance gap with sensor positioning error and without, and illustrate the better source localization accuracy by OSP. © 1965-2011 IEEE.

关键词： Cramer-Rao bounds

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Physical Review Letters 2022年第2期128卷 026802-026802页

作者： Yoon Jang Chung D. Graf L. W. Engel K. A. Villegas Rosales P. T. Madathil K. W. Baldwin K. W. West L. N. Pfeiffer M. Shayegan Department of Electrical and Computer Engineering Princeton University Princeton New Jersey 08544 USA National High Magnetic Field Laboratory Tallahassee Florida 32310 USA

The ground state of two-dimensional electron systems (2DESs) at low Landau level filling factors (ν≲1/6) has long been a topic of interest and controversy in condensed matter. Following the recent breakthrough in the quality of ultrahigh-mobility GaAs 2DESs, we revisit this problem experimentally and investigate the impact of reduced disorder. In a GaAs 2DES sample with density n=6.1×1010/cm2 and mobility μ=25×106 cm2/V s, we find a deep minimum in the longitudinal magnetoresistance (Rxx) at ν=1/7 when T≃104 mK. There is also a clear sign of a developing minimum in Rxx at ν=2/13. While insulating phases are still predominant when ν≲1/6, these minima strongly suggest the existence of fractional quantum Hall states at filling factors that comply with the Jain sequence ν=p/(2mp±1) even in the very low Landau level filling limit. The magnetic-field-dependent activation energies deduced from the relation Rxx∝eEA/2kT corroborate this view and imply the presence of pinned Wigner solid states when ν≠p/(2mp±1). Similar results are seen in another sample with a lower density, further generalizing our observations.

关键词： Composite fermions Fractional quantum Hall effect Landau levels Two-dimensional electron gas Wigner crystal Dilution refrigerator

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