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Knowledge and Data Dual-Driven Channel Estimation and Feedback for Ultra-Massive MIMO Systems under Hybrid Field Beam Squint Effect

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arXiv 2024年

作者： Wang, Kuiyu Gao, Zhen Chen, Sheng Ning, Boyu Chen, Gaojie Su, Yu Wang, Zhaocheng Poor, H. Vincent Beijing100081 China The School of Electronics and Computer Science University of Southampton SouthamptonSO17 1BJ United Kingdom The National Key Laboratory of Wireless Communications University of Electronic Science and Technology of China Chengdu611731 China The 5GIC & 6GIC Institute for Communication Systems University of Surrey GuildfordGU2 7XH United Kingdom The China Mobile Chengdu Institute of Research and Development Chengdu610000 China The Department of Electronic Engineering Tsinghua University Beijing100084 China The Shenzhen International Graduate School Tsinghua University Shenzhen518055 China The Department of Electrical and Computer Engineering Princeton University PrincetonNJ08544 United States

Acquiring accurate channel state information (CSI) at an access point (AP) is challenging for wideband millimeter wave (mmWave) ultra-massive multiple-input and multiple-output (UM-MIMO) systems, due to the high-dimensional channel matrices, hybrid near- and far- field channel feature, beam squint effects, and imperfect hardware constraints, such as low-resolution analog-to-digital converters, and in-phase and quadrature imbalance. To overcome these challenges, this paper proposes an efficient downlink channel estimation (CE) and CSI feedback approach based on knowledge and data dual-driven deep learning (DL) networks. Specifically, we first propose a data-driven residual neural network de-quantizer (ResNet-DQ) to pre-process the received pilot signals at user equipment (UEs), where the noise and distortion brought by imperfect hardware can be mitigated. A knowledge-driven generalized multiple measurement vector learned approximate message passing (GMMV-LAMP) network is then developed to jointly estimate the channels by exploiting the approximately same physical angle shared by different subcarriers. In particular, two wideband redundant dictionaries (WRDs) are proposed such that the measurement matrices of the GMMV-LAMP network can accommodate the far-field and near-field beam squint effect, respectively. Finally, we propose an encoder at the UEs and a decoder at the AP by a data-driven CSI residual network (CSI-ResNet) to compress the CSI matrix into a low-dimensional quantized bit vector for feedback, thereby reducing the feedback overhead substantially. Simulation results show that the proposed knowledge and data dual-driven approach outperforms conventional downlink CE and CSI feedback methods, especially in the case of low signal-to-noise ratios. Copyright © 2024, The Authors. All rights reserved.

关键词： Orthogonal frequency division multiplexing

Effects of Outdoor Air Pollution on Human Health in Mohammedia, "Morocco" 2nd

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Effects of Outdoor Air Pollution on Human Health in Mohammed...

2nd Euro-Mediterranean Conference on Environmental Integration, EMCEI 2019

作者： El Morabet, Rachida El Ouadrhiri, Abderrahmane Adoui Khan, Roohul Abad Mouak, Said Aneflouss, Mohamed Department of Geography LADES FLSH-M Hassan II University of Casablanca B.P. 546 Mohammedia Morocco Department of Mathematics and Computer Science LR2I FSAC Hassan II University of Casablanca B.P. 5366 Maarif Casablanca Morocco Department of Civil Engineering King Khalid University Abha Saudi Arabia

ISBN: (纸本)9783030512095

In developing countries such as Morocco, the concentration of air pollutants has been steadily increasing since the Industrial Revolution in the 1970s;this level has reached a very large-scale in big cities. Therefore, it is extremely important to describe the problem, especially its toxic effects on human health. The study identified the sources of air pollutants in Mohammedia, which is one of the leading industrial cities in Morocco, it analyzed the weather and clinical data through a mathematical and geographical model and presented their various toxicological impacts. As a result, each pollutant affects part or parts of the body’s functions at the human organ systems. We point out that the study is based, in particular, on data of 2014, 2015, and 2016. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Geographic information systems

In Defense of Subspace Tracker: Orthogonal Embedding for Visual Tracking

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arXiv 2022年

作者： Sui, Yao Wang, Guanghui Zhang, Li Harvard Medical School Harvard University BostonMA02115 United States The Department of Computer Science Ryerson University TorontoONM5B 2K3 Canada The Department of Electronic Engineering Tsinghua University Beijing100084 China

The paper focuses on a classical tracking model, subspace learning, grounded on the fact that the targets in successive frames are considered to reside in a low-dimensional subspace or manifold due to the similarity in their appearances. In recent years, a number of subspace trackers have been proposed and obtained impressive results. Inspired by the most recent results that the tracking performance is boosted by the subspace with discrimination capability learned over the recently localized targets and their immediately surrounding background, this work aims at solving such a problem: how to learn a robust low-dimensional subspace to accurately and discriminatively represent these target and background samples. To this end, a discriminative approach, which reliably separates the target from its surrounding background, is injected into the subspace learning by means of joint learning, achieving a dimension-adaptive subspace with superior discrimination capability. The proposed approach is extensively evaluated and compared with the state-of-the-art trackers on four popular tracking benchmarks. The experimental results demonstrate that the proposed tracker performs competitively against its counterparts. In particular, it achieves more than 9% performance increase compared with the state-of-the-art subspace trackers. © 2022, CC BY.

关键词： Embeddings

Realization of High-power DFB Lasers with Single and Multiple Partially Corrugated Gratings

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Realization of High-power DFB Lasers with Single and Multipl...

Microopics Conference (MOC)

作者： Siti Sulikhah Kai-Chun Ma San-Liang Lee Charng-Gan Tu Ing-Fa Jang Hung-Pin Shiao Hen-Wai Tsao Department of Electronic and Computer Engineering National Taiwan University of Science and Technology No. 43 Sec. 4 Keelung Rd. Taipei Taiwan WIN Semiconductors No. 358 Hwaya 2nd Rd. Hwaya Technology Park Taoyuan Taiwan Department of Electrical Engineering National Taiwan University No. 1 Sec. 4 Roosevelt Rd. Taipei Taiwan

Cascaded partially-corrugated gratings (CPCGs) are designed to realize high-power DFB lasers for co-packaged-optics applications. CPCGs allow for manipulating the longitudinal power distribution in laser cavity to increase output power. By optimizing the grating ratio, >37.837% increase in output power and >97.3% single-mode-yield can be obtained even at high operation temperature.

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The electron cyclotron drift instability: a comparison of particle-in-cell and continuum Vlasov simulations

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arXiv 2022年

作者： Tavassoli, Arash Zadeh, Mina Papahn Smolyakov, Andrei Shoucri, Magdi Spiteri, Raymond J. Department of Physics and Engineering Physics University of Saskatchewan SaskatoonSKS7N 5E2 Canada Department of Computer Science University of Saskatchewan SaskatoonSKS7N 5C9 Canada

The linear and nonlinear characteristics of the electron cyclotron drift instability (ECDI) have been studied through the particle-in-cell (PIC) and continuum Vlasov simulation methods in connection with the effects of the azimuthal length (in the E × B direction) on the simulations. Simulation results for a long azimuthal length (17.82 cm = 627 vd/ωce, where ωce is the electron cyclotron frequency and vd is the E × B drift of the electrons) are reported, for which a high resolution is achieved in Fourier space. For simulations with a long azimuthal length, the linear growth rates of the PIC simulations show a considerable discrepancy with the theory, whereas the linear growth rate of the Vlasov simulations remains close to the theory. In the nonlinear regime, the inverse cascade is shown in both PIC and Vlasov simulations with a sufficiently large azimuthal length. In simulations with a short azimuthal length, however, the inverse cascade is barely observed. Instead, the PIC simulations with a short azimuthal length (0.5625 cm = 19.8 vd/ωce) show an essentially continuous nonlinear dispersion, similar to what is predicted by the ion-sound turbulence theory. It is shown that, in the PIC and Vlasov simulations, the inverse cascade coincides with the formation and merging of electron structures in phase space. This process, however, terminates differently in the PIC simulations compared with the Vlasov simulations. Larger amplitudes of ECDI fluctuations are observed in the PIC simulations compared with the Vlasov simulations, leading to an intensified electron heating and anomalous current. This suggests that the statistical noise of PIC simulations might contribute to the extreme electron heating that has been observed in previous studies. © 2022, CC BY-NC-ND.

关键词： Electrons

Multi-Domain Active Learning: Literature Review and Comparative Study

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arXiv 2021年

作者： He, Rui Liu, Shengcai He, Shan Tang, Ke Guangdong Provincial Key Laboratory of Brain-Inspired Intelligent Computation Department of Computer Science and Engineering Southern University of Science and Technology Shenzhen518055 China School of Computer Science University of Birmingham BirminghamB15 2TT United Kingdom

Multi-domain learning (MDL) refers to learning a set of models simultaneously, where each model is specialized to perform a task in a particular domain. Generally, a high labeling effort is required in MDL, as data needs to be labeled by human experts for every domain. Active learning (AL) can be utilized in MDL to reduce the labeling effort by only using the most informative data. The resultant paradigm is termed multi-domain active learning (MDAL). In this work, we provide an exhaustive literature review for MDAL on the relevant fields, including AL, cross-domain information sharing schemes, and cross-domain instance evaluation approaches. It is found that the few studies which have been directly conducted on MDAL cannot serve as off-the-shelf solutions on more general MDAL tasks. To fill this gap, we construct a pipeline of MDAL and present a comprehensive comparative study of thirty different algorithms, which are established by combining six representative MDL models and five commonly used AL strategies. We evaluate the algorithms on six datasets involving textual and visual classification tasks. In most cases, AL brings notable improvements to MDL, and the naive BvSB (best vs. second best) Uncertainty strategy can perform competitively with the state-of-the-art AL strategies. Besides, BvSB with the MAN (multinomial adversarial networks) model can consistently achieve top or above-average performance on all the datasets. Furthermore, we qualitatively analyze the behaviors of the well-performed strategies and models, shedding light on their superior performance in the comparison. Finally, we recommend using BvSB with the MAN model in the application of MDAL due to their good performance in the experiments. Copyright © 2021, The Authors. All rights reserved.

关键词： Classification (of information)

Enhanced quantum emission from a topological Floquet resonance

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arXiv 2023年

作者： Afzal, Shirin Zimmerling, Tyler J. Rizvandi, Mahdi Taghavi, Majid Esmaeilifar, Leili Hrushevskyi, Taras Kaur, Manpreet Van, Vien Barzanjeh, Shabir Institute for Quantum Science and Technology Department of Physics and Astronomy University of Calgary 2500 University Drive NW CalgaryABT2N 1N4 Canada Department of Electrical and Computer Engineering University of Alberta 9211 116 Street NW EdmontonABT6G 1H9 Canada

Entanglement is a valuable resource in quantum information technologies. The practical implementation of entangled photon sources faces obstacles from imperfections and defects inherent in physical systems, resulting in a loss or degradation of entanglement. The topological photonic insulators, however, have emerged as promising candidates, demonstrating an exceptional capability to resist defect-induced scattering, thus enabling the development of robust entangled sources. Despite their inherent advantages, building programmable topologically protected entangled sources remains challenging due to complex device designs and weak material nonlinearity. Here we present a development in entangled photon pair generation achieved through a non-magnetic and tunable anomalous Floquet insulator, utilizing an optical spontaneous four-wave mixing process. We verify the non-classicality and time-energy entanglement of the photons generated by our topological system. Our experiment demonstrates a substantial enhancement in nonclassical photon pair generation compared to devices reliant only on topological edge states. Our result could lead to the development of resilient quantum sources with potential applications in quantum technology. © 2023, CC BY.

关键词： Four wave mixing

A systematic review of mobile apps for child sexual abuse education: Limitations and design guidelines

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arXiv 2021年

作者： Pritha, Sadia Tasnuva Tasnim, Rahnuma Kabir, Muhammad Ashad Amin, Sumaiya Das, Anik Department of Computer Science and Engineering Chittagong University of Engineering and Technology Chattogram4349 Bangladesh School of Computing and Mathematics Charles Sturt University Panorama Ave BathurstNSW2795 Australia Department of Computer Science St. Francis Xavier University AntigonishNSB2G 2W5 Canada

With the availability of many child sexual abuse (CSA) education apps in different app stores, the demand for an evaluation system has become necessary as little information regarding their evidence-based quality is available. The objectives of this study are understanding the requirements of a CSA education app, identifying the limitations of existing apps, and providing a guideline for better app design. An electronic search across three major app stores (Google Play, Apple, and Microsoft) is conducted and the selected apps are rated by three independent raters. Total 191 apps are found and finally, 14 apps are selected for review based on defined inclusion and exclusion criteria. An app rating scale for CSA education apps is devised by modifying existing scales and used to evaluate the selected 14 apps. Our rating scale evaluates essential features, criteria, and software quality characteristics that are necessary for CSA education apps, and determined their effectiveness for potential use as CSA education programs for children. The internal consistency of the rating scale and the inter and intra-rater reliability among the raters are also calculated. User comments from the app stores are collected and analyzed to understand their expectations and views. After analyzing the feasibility of reviewed apps, CSA app design considerations are proposed that highlight game-based teaching approaches. Evaluation results showed that most of the reviewed apps are not suitable for being used as CSA education programs. While a few may be able to teach children and parents individually, only the apps "Child Abuse Prevention" (rate 3.89 out of 5) and "Orbit Rescue" (rate 3.92 out of 5) could be deemed suitable for a school-based CSA education program. However, all those apps need to be improved both their software qualities and CSA-specific features for being considered as potential CSA education programs. This study provides the necessary knowledge to developers and individuals

关键词： Design

Room-temperature waveguide-coupled silicon single-photon avalanche diodes

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arXiv 2023年

作者： Govdeli, Alperen Straguzzi, John N. Yong, Zheng Lin, Yiding Luo, Xianshu Chua, Hongyao Lo, Guo-Qiang Sacher, Wesley D. Poon, Joyce K.S. Max Planck Institute of Microstructure Physics Weinberg 2 Halle06120 Germany Department of Electrical and Computer Engineering University of Toronto 10 King’s College Road TorontoONM5S 3G4 Canada Advanced Micro Foundry Pte Ltd 11 Science Park Road Singapore Science Park II Singapore117685 Singapore

Single photon detection is important for a wide range of low-light applications, including quantum information processing, spectroscopy, and light detection and ranging (LiDAR). A key challenge in these applications has been to integrate single-photon detection capability into photonic circuits for the realization of complex photonic microsystems. Short-wavelength (λ 6% for wavelengths of 488 nm and 532 nm with an excess voltage less than 20% of the breakdown voltage. The dark count rate was below 100 kHz at room temperature, with the possibility of improving by approximately 35% by reducing the temperature to -5◦C. © 2023, CC BY-NC-ND.

关键词： Silicon