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DisCoBeam for Future WPT Applications

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DisCoBeam for Future WPT Applications

Wireless Power Week (WPW)

作者： Tien M. Nguyen Charles H. Lee Roy Nakagawa Ching-Yao Tony Tang Sam Behseta Civil & Allied Partnerships The Aerospace Corporation El Segundo California USA Department of Mathematics California State University in Fullerton (CSUF) California USA Civil & Allied Partnerships The Aerospace Corporation El Segundo California International Programs The Aerospace Corporation El Segundo California Center for Computational and Applied Mathematics (CCAM) CSUF California USA

ISBN: (数字)9798350349139

ISBN: (纸本)9798350349146

This paper presents an advanced Distributed Coherent Beamforming (DisCoBeam) concept that can potentially be used to enable a low-cost space-based wireless power transmission (WPT) solution. The proposed concept uses a proliferated low Earth orbit (pLEO) CubeSat constellation. The constellation consists of N number of low size, weight, power, and cost (SWaP-C) satellites. The DisCoBeam concept requires each satellite to be equipped with solar power collecting arrays, a microwave transmitting antenna, and a GPS receiver for accurate position, navigation, and timing (PNT). This allows the satellites to work together to form a coherent microwave beam on a targeted ground rectenna receiver (RX) . Under ideal operational conditions, it will be shown that the proposed DisCoBeam concept can enhance the space-based WPT efficiency by a factor of N-squared. Leveraging the dynamic systems-of-systems (SoS) MATLAB simulator developed by CSUF team for unmanned aerial system (UAS) platforms, we show that the proposed DisCoBeam can achieve about 72% of N-squared at the maximum slant range assuming the PNT of each UAS platform are known precisely and the flight-path strategy results in a linear uniformly-distributed beamforming array within a 1-mile square area with a maximum number of 10 UAS platforms. Finally, the paper discusses the extension of the UAS results to the proposed pLEO satellites scenario.

关键词： Wireless communication Satellite antennas Satellites Array signal processing Rectennas Transmitting antennas Receiving antennas

Theory of degenerate three-wave mixing using circuit QED in solid-state circuits

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Physical Review A 2011年第5期84卷 053846-053846页

作者： Ye Cao (曹业) Wen Yi Huo (霍文义) Qing Ai (艾清) Gui Lu Long (龙桂鲁) Key Laboratory of Atomic and Molecular Nanosciences and Department of Physics Tsinghua University Beijing 100084 China Institute of Applied Physics and Computational Mathematics Beijing 100088 China Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China Tsinghua National Laboratory For Information Science and Technology Beijing 100084 China

We study the theory of degenerate three-wave mixing and the generation of squeezed microwaves using circuit quantum electrodynamics in solid state circuits. The Hamiltonian for degenerate three-wave mixing, which seemed to be given phenomenologically in quantum optics, is derived by quantum mechanical calculations. The nonlinear medium needed in three-wave mixing is composed of a series of superconducting charge qubits which are located inside two superconducting transmission-line resonators. Here, the multiqubit ensemble is present to enhance the effective coupling constant between the two modes in the transmission-line resonators. In the squeezing process, the qubits are kept in their ground states so that their decoherence does not corrupt the squeezing. The main obstacle preventing a large squeezing efficiency is the decay rate of the transmission-line resonator.

关键词： MICROWAVES SQUEEZED light QUANTUM electrodynamics SOLID state electronics NONLINEAR theories RESONATORS SUPERCONDUCTORS

An equivalent reformulation and multi-proximity gradient algorithms for a class of nonsmooth fractional programming

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arXiv 2023年

作者： Zhou, Junpeng Zhang, Na Li, Qia School of Computer Sciences and Engineering Sun Yat-Sen University Guangzhou510006 China Department of Applied Mathematics College of Mathematics and Informatics South China Agricultural University Guangzhou510642 China School of Computer Sciences and Engineering Guangdong Province Key Laboratory of Computational Science Sun Yat-Sen University Guangzhou510006 China

In this paper, we consider a class of structured fractional programs, where the numerator part is the sum of a block-separable (possibly nonsmooth nonconvex) function and a locally Lipschitz differentiable (possibly nonconvex) function, while the denominator is a convex (possibly nonsmooth) function. We first present a novel reformulation for the original problem and show the relationship between optimal solutions, critical points and KL exponents of these two problems. Inspired by the reformulation, we propose a flexible framework of multi-proximity gradient algorithms (MPGA), which computes the proximity operator with respect to the Fenchel conjugate associated with the convex denominator of the original problem rather than evaluating its subgradient as in the existing methods. Also, MPGA employs a nonmonotone linear-search scheme in its gradient descent step, since the smooth part in the numerator of the original problem is not globally Lipschitz differentiable. Based on the framework of MPGA, we develop two specific algorithms, namely, cyclic MPGA and randomized MPGA, and establish their subsequential convergence under mild conditions. Moreover, the sequential convergence of cyclic MPGA with the monotone line-search (CMPGA ML) is guaranteed if the extended objective associated with the reformulated problem satisfies the Kurdyka-Lojasiewicz (KL) property and some other mild assumptions. In particular, we prove that the corresponding KL exponents are 12 for several special cases of the fractional programs, and so, CMPGA ML exhibits a linear convergence rate. Finally, some preliminary numerical experiments are performed to demonstrate the efficiency of our proposed algorithms. Copyright © 2023, The Authors. All rights reserved.

关键词： Gradient methods

Dermatological Diagnostics: A Unified Deep Learning Framework for Skin Lesion and Cancer Classification 1

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Dermatological Diagnostics: A Unified Deep Learning Framewor...

1st IEEE International Conference on Advances in Computing, Communication and Networking, ICAC2N 2024

作者： Kumar, Vinod Jain, Isha Dongla, Durga Sritha Rai, Shivangi Rastogi, Vani Kaushik, Eva Kaushik, Rohit George Washington University School of Engineering and Applied Science WashingtonDC United States Dr. Akhilesh Das Gupta Institute of Technology and Management Computer Science and Engineering Department New Delhi India Gandhi Institute of Technology and Management Computer Science and Engineering Department Andhra Pradesh Visakhapatnam India Data Scientist DXC Technology Noida India Data Analytics Program University of Illinois CS and Mathematics Department Springfield United States

ISBN: (纸本)9798350356816

Skin pathologies encompass a spectrum of conditions, with malignancies such as melanoma representing a critical diagnostic urgency. This investigation delineates the deployment of Convolutional Neural Networks (CNNs) for the classification of dermatological anomalies, benchmarking CNN diagnostic fidelity against dermatological expert evaluations. The study underscores the efficacy of CNN classifiers in expediting the diagnostic workflow for various cutaneous disorders. Advocating for an automated diagnostic framework, the research introduces a CNN-based system aimed at reducing human diagnostic load, accelerating diagnostic timelines, and enhancing survival outcomes. Utilizing advanced image processing algorithms and deep learning architectures, the research presents an automated classification system for skin pathologies, addressing both benign and malignant presentations. The classification matrix includes nine dermatological conditions: actinic keratosis, basal cell carcinoma, benign keratosis, dermatofibroma, melanoma, nevus, seborrheic keratosis, squamous cell carcinoma, and vascular lesions. The objective is to engineer a CNN model with robust diagnostic performance across a diverse lesion dataset, ensuring accurate identification and categorization of dermatological conditions. © 2024 IEEE.

关键词： Convolutional neural networks

Characterizing the hyperuniformity of ordered and disordered two-phase media

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arXiv 2020年

作者： Kim, Jaeuk Torquato, Salvatore Department of Physics Princeton University PrincetonNJ08544 United States Department of Chemistry Princeton University PrincetonNJ08544 United States Princeton Institute for the Science and Technology of Materials Princeton University PrincetonNJ08544 United States Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States

The hyperuniformity concept provides a unified means to classify all perfect crystals, perfect quasicrystals, and exotic amorphous states of matter according to their capacity to suppress large-scale density fluctuations. While the classification of hyperuniform point configurations has received considerable attention, much less is known about the classification of hyperuniform heterogeneous two-phase media, which include composites, porous media, foams, cellular solids, colloidal suspensions and polymer blends. The purpose of this article is to begin such a program for certain two-dimensional models of hyperuniform two-phase media by ascertaining their local volume-fraction variances σV2 (R) and the associated hyperuniformity order metrics BV . This is a highly challenging task because the geometries and topologies of the phases are generally much richer and more complex than point-configuration arrangements and one must ascertain a broadly applicable length scale to make key quantities dimensionless. Therefore, we purposely restrict ourselves to a certain class of two-dimensional periodic cellular networks as well as periodic and disordered/irregular packings, some of which maximize their effective transport and elastic properties. Among the cellular networks considered, the honeycomb networks have the minimal value of the hyperuniformity order metrics BV across all volume fractions. On the other hand, among all packings considered, the triangular-lattice packings have the smallest values of BV for the possible range of volume fractions. Among all structures studied here, the triangular-lattice packing has the minimal order metric for almost all volume fractions. Our study provides a theoretical foundation for the establishment of hyperuniformity order metrics for general two-phase media and a basis to discover new hyperuniform two-phase systems by inverse design procedures. Copyright © 2020, The Authors. All rights reserved.

关键词： Wireless networks

Methodology to construct large realizations of perfectly hyperuniform disordered packings

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arXiv 2019年

Disordered hyperuniform packings (or dispersions) are unusual amorphous two-phase materials that are endowed with exotic physical properties. Such hyperuniform systems are characterized by an anomalous suppression of volume-fraction fluctuations at infinitely long-wavelengths, compared to ordinary disordered materials. While there has been growing interest in such singular states of amorphous matter, a major obstacle has been an inability to produce large samples that are perfectly hyperuniform due to practical limitations of conventional numerical and experimental methods. To overcome these limitations, we introduce a general theoretical methodology to construct perfectly hyperuniform packings in d-dimensional Euclidean space Rd. Specifically, beginning with an initial general tessellation of space by disjoint cells that meets a "bounded-cell" condition, hard particles are placed inside each cell such that the local-cell particle packing fractions are identical to the global packing fraction. We prove that the constructed packings with a polydispersity in size in Rd are perfectly hyperuniform in the infinite-sample-size limit and the hyperuniformity of such packings is independent of particle shapes, positions, and numbers per cell. We use this theoretical formulation to devise an efficient and tunable algorithm to generate extremely large realizations of such packings. We employ two distinct initial tessellations: Voronoi as well as sphere tessellations. Beginning with Voronoi tessellations, we show that our algorithm can remarkably convert extremely large nonhyperuniform packings into hyperuniform ones in R2 and R3. Implementing our theoretical methodology on sphere tessellations, we establish the hyperuniformity of the classical Hashin-Shtrikman multiscale coated-spheres structures, which are known to be two-phase media microstructures that possess optimal effective transport and elastic properties. A consequence of our work is a rigorous demonstration that pack

关键词： Cells

Optical properties of coupled metal-semiconductor and metal-molecule nanocrystal complexes: Role of multipole effects

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Physical Review B 2008年第16期77卷 165301-165301页

作者： Jie-Yun Yan Wei Zhang Suqing Duan Xian-Geng Zhao Alexander O. Govorov Institute of Applied Physics and Computational Mathematics P.O. Box 8009 Beijing 100088 People’s Republic of China Department of Physics Tsinghua University Beijing 100084 People’s Republic of China Department of Physics and Astronomy Ohio University Athens Ohio 45701-2979 USA

We theoretically investigate the effects of interaction between an optical dipole (semiconductor quantum dot or molecule) and metal nanoparticles. The calculated absorption spectra of hybrid structures demonstrate strong effects of interference coming from the exciton-plasmon coupling. In particular, the absorption spectra acquire characteristic asymmetric line shapes and strong antiresonances. We present here an exact solution of the problem beyond the dipole approximation and find that the multipole treatment of the interaction is crucial for the understanding of strongly interacting exciton-plasmon nanosystems. Interestingly, the visibility of the exciton resonance becomes greatly enhanced for small interparticle distances due to the interference phenomenon, multipole effects, and electromagnetic enhancement. We find that the destructive interference is particularly strong. Using our exact theory, we show that the interference effects can be experimentally observed in the exciting systems even at room temperature.

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Designing disordered hyperuniform two-phase materials with novel physical properties

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arXiv 2017年

作者： Chen, D. Torquato, S. Department of Chemistry Princeton University PrincetonNJ08544 United States Department of Physics Princeton University PrincetonNJ08544 United States Princeton Institute for the Science and Technology of Materials Princeton University PrincetonNJ08544 United States Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States

Heterogeneous materials consisting of different phases are ideally suited to achieve a broad spectrum of desirable bulk physical properties by combining the best features of the constituents through the strategic spatial arrangement of the different phases. Disordered hyperuniform heterogeneous materials are new, exotic amorphous matter that behave like crystals in the manner in which they suppress volume-fraction fluctuations at large length scales, and yet are isotropic with no Bragg peaks. In this paper, we formulate for the first time a Fourier-space numerical construction procedure to design at will a wide class of disordered hyperuniform two-phase materials with prescribed spectral densities, which enables one to tune the degree and length scales at which this suppression occurs. We demonstrate that the anomalous suppression of volume-fraction fluctuations in such two-phase materials endow them with novel and often optimal transport and electromagnetic properties. Specifically, we construct a family of phase-inversion-symmetric materials with variable topological connectedness properties that remarkably achieves a well-known explicit formula for the effective electrical (thermal) conductivity. Moreover, we design disordered stealthy hyperuniform dispersion that possesses nearly optimal effective conductivity while being statistically isotropic. Interestingly, all of our designed materials are transparent to electromagnetic radiation for certain wavelengths, which is a common attribute of all hyperuniform materials. Our constructed materials can be readily realized by 3D printing and lithographic technologies. We expect that our designs will be potentially useful for energy-saving materials, batteries and aerospace applications. Copyright © 2017, The Authors. All rights reserved.

关键词： Volume fraction

Spread Complexity and Topological Transitions in the Kitaev Chain

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arXiv 2022年

作者： Caputa, Pawel Gupta, Nitin Haque, S. Shajidul Liu, Sinong Murugan, Jeff Van Zyl, Hendrik J.R. Faculty of Physics University of Warsaw ul. Pasteura 5 Warsaw02-093 Poland The Laboratory for Quantum Gravity & Strings Department of Mathematics & Applied Mathematics University of Cape Town Cape Town South Africa The National Institute for Theoretical and Computational Sciences Private Bag X1 Matieland South Africa

A number of recent works have argued that quantum complexity, a well-known concept in computer science that has re-emerged recently in the context of the physics of black holes, may be used as an efficient probe of novel phenomena such as quantum chaos and even quantum phase transitions. In this article, we provide further support for the latter, using a 1-dimensional p-wave superconductor - the Kitaev chain - as a prototype of a system displaying a topological phase transition. The Hamiltonian of the Kitaev chain manifests two gapped phases of matter with fermion parity symmetry;a trivial strongly-coupled phase and a topologically non-trivial, weakly-coupled phase with Majorana zero-modes. We show that Krylov-complexity (or, more precisely, the associated spread-complexity) is able to distinguish between the two and provides a diagnostic of the quantum critical point that separates them. We also comment on some possible ambiguity in the existing literature on the sensitivity of different measures of complexity to topological phase transitions. © 2022, CC BY.

关键词： Phase transitions