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Quasielectrostatic Wave Propagation Beyond the Delay-Bandwidth Limit in Switched Networks

Physical Review X 2019年第3期9卷 031015-031015页

作者： Mykhailo Tymchenko Dimitrios Sounas Aravind Nagulu Harish Krishnaswamy Andrea Alù Department of Electrical and Computer Engineering The University of Texas at Austin 1 University Station C0803 Austin Texas 78712 USA Department of Electrical and Computer Engineering Wayne State University Detroit Michigan 48202 USA Department of Electrical Engineering Columbia University 1300 South West Mudd 500 West 120th Street New York New York 10027 USA Photonics Initiative Advanced Science Research Center City University of New York New York New York 10031 USA Physics Program Graduate Center City University of New York New York New York 10026 USA Department of Electrical Engineering City College of New York New York New York 10031 USA

The delay-bandwidth limit implies a stringent trade-off between the time delay, bandwidth, and propagation distance of an electromagnetic signal. Here, we show that temporal modulation can overcome this constraint, enabling extremely broadband wave propagation with close-to-zero group velocity dispersion in switched multipath electronic networks. Contrary to time-invariant waveguides, in which wave propagation implies a delicate balance between electric and magnetic stored energies, in such modulated networks the stored energy is largely electrostatic in nature. We show that in this case the phase and group velocities become independent of the properties of their constituent elements, and they are controlled only by the modulation scheme. Based on these findings, we provide practical designs of deeply subwavelength CMOS-compatible reciprocal and nonreciprocal microwave components, such as delay lines, phase shifters, couplers, and circulators. The obtained results also explicitly show that temporally modulated systems are not bound by constraints of time-invariant systems and can achieve arbitrarily large delay-bandwidth products.

关键词： Metamaterials

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Atomic-Scale Defect Detection by Nonlinear Light Scattering and Localization

arXiv

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arXiv 2020年

作者： Shafiei, Farbod Orzali, Tommaso Vert, Alexey Miri, Mohammad-Ali Hung, P.Y. Wong, Man Hoi Alù, Andrea Bersuker, Gennadi Downer, Michael C. Department of Physics University of Texas at Austin AustinTX United States SEMATECH AlbanyNY United States Sunny Polytechnic Institute AlbanyNY United States Department of Electrical and Computer Engineering University of Texas at Austin AustinTX United States Department of Physics Queens College of the CUNY QueensNY United States Photonics Initiative Advanced Science Research Center CUNY New YorkNY United States Physics Program Graduate Center CUNY New YorkNY United States Aerospace Corporation Los AngelesCA United States

Hetero-epitaxial crystalline films underlie many electronic and optical technologies but are prone to forming defects at their hetero-interfaces. Atomic-scale defects such as threading dislocations that propagate into a film impede the flow of charge carriers and light degrading electrical/optical performance of devices. Diagnosis of sub-surface defects traditionally requires time-consuming invasive techniques such as cross–sectional transmission electron microscopy. Using III-V films grown on Si, we have demonstrated noninvasive, bench-top diagnosis of sub-surface defects by optical second-harmonic scanning probe microscope. We observed a high-contrast pattern of sub-wavelength "hot spots" caused by scattering and localization of fundamental light by defect scattering sites. Size of these observed hotspots are strongly correlated to the density of dislocation defects. Our results not only demonstrate a global and versatile method for diagnosing sub-surface scattering sites but uniquely elucidate optical properties of disordered media. An extension to third harmonics would enable irregularities detection in non-χ(2) materials making the technique universally applicable. Copyright © 2020, The Authors. All rights reserved.

关键词： High resolution transmission electron microscopy

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Author Correction: Cortical astrocytes modulate dominance behavior in male mice by regulating synaptic excitatory and inhibitory balance

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Nature neuroscience 2023年第12期26卷 2250页

作者： Kyungchul Noh Woo-Hyun Cho Byung Hun Lee Dong Wook Kim Yoo Sung Kim Keebum Park Minkyu Hwang Ellane Barcelon Yoon Kyung Cho C Justin Lee Bo-Eun Yoon Se-Young Choi Hye Yoon Park Sang Beom Jun Sung Joong Lee Department of Physiology and Neuroscience Dental Research Institute Seoul National University School of Dentistry Seoul Republic of Korea. Department of Physics and Astronomy Seoul National University Seoul Republic of Korea. Department of Molecular Biology Dankook University Cheonan Republic of Korea. Department of Electronic and Electrical Engineering Ewha Womans University Seoul Republic of Korea. Center for Cognition and Sociality Institute for Basic Science (IBS) Daejeon Republic of Korea. Department of Electrical and Computer Engineering University of Minnesota Minneapolis MN USA. Graduate Program in Smart Factory Ewha Womans University Seoul Republic of Korea. Department of Brain & Cognitive Sciences Ewha Womans University Seoul Republic of Korea. Department of Physiology and Neuroscience Dental Research Institute Seoul National University School of Dentistry Seoul Republic of Korea. sjlee87@snu.ac.kr.

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Development of a smartphone-based app for determination of formaldehyde concentration indoors 15

Development of a smartphone-based app for determination of f...

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15th Conference of the International Society of Indoor Air Quality and Climate, INDOOR AIR 2018

作者： Zhang, Siyang Shapiro, Nicholas Gehrke, Gretchen Castner, Jessica Liu, Zhenlei Guo, Beverly Zhang, Jianshun Haines, Sarah Kormos, David Frey, Paige Qin, Rongjun Dannemiller, Karen C. Department of Computer Science and Engineering Ohio State University United States Public Laboratory for Open Technology and Science Department of Mechanical and Aerospace Engineering Syracuse University Environmental Science Graduate Program Ohio State University United States Department of Civil Environmental and Geodetic Engineering College of Engineering Ohio State University United States Strand Associates Incorporated Department of Electrical and Computer Engineering Ohio State University United States Department of Environmental Health Sciences College of Public Health Ohio State University United States

ISBN: (纸本)9781713826514

Formaldehyde is a ubiquitous contaminant in the indoor environment that is both a carcinogen and irritant. The goal of this project is to develop a smartphone-based app for use by citizen scientists or researchers that can be paired with low-cost colorimetric badges for detection of indoor formaldehyde. We conducted both national and geographically-targeted surveys prior to app design. We have subsequently developed the app and conducted a beta test. Surveys of 147 individuals indicated broad public interest in formaldehyde testing using smartphone technology. Testing of the badges indicated consistent change in illumination with increasing formaldehyde exposure. Beta testing indicated users were able to navigate the existing app, and highlighted areas for improvement including incorporation of public surveys. Planned future analysis includes extensive calibration testing and a community-based field test. © 2018 15th Conference of the International Society of Indoor Air Quality and Climate, INDOOR AIR 2018. All rights reserved.

关键词： Formaldehyde

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Clustering with Minimum Spanning Tree using TOPSIS with Multi-Criteria Information

Clustering with Minimum Spanning Tree using TOPSIS with Mult...

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IEEE International Conference on Fuzzy Systems

作者： Jose G. M. Esgario Renato A. Krohling Graduate Program in Computer Science PPGI Federal University of Espírito Santo – UFES Vitória ES Brasil Production Engineering Department LABCIN & Graduate Program in Computer Science PPGI Federal University of Espírito Santo - UFES Vitória ES Brasil

Clustering is the process of grouping similar objects into the same partition and keeping dissimilar objects on different partitions. Clustering algorithms based on Minimum Spanning Tree (MST) have been successfully applied in the separation of non-convex clusters, although the use of individual objective functions limits the algorithms to a reduced set of clustering problems, presenting difficulties in cases of unbalanced, noisy, overlapping datasets, etc. In order to make clustering process more robust, this paper proposes an algorithm based on Minimum Spanning Tree that combines different objective functions using TOPSIS. The algorithm performance was evaluated on real and synthetic datasets. Experimental results indicate that the combination of objective functions improves clustering results compared to individual functions.

关键词： Clustering algorithms Linear programming Partitioning algorithms Euclidean distance Optimization Mutual information computer science

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Calibration of a type 2 controller applied to a buck converter: a multi-objective analysis

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Electronic Notes in Discrete Mathematics 2018年 66卷 199-206页

作者： Ferreira, Diógenes V.M. Coelho, Vitor N. Graduate Program in Electrical Engineering Universidade Federal de Minas Gerais Belo Horizonte Brazil Laboratório de Automação Predial Universidade Federal de Ouro Preto Brazil Grupo da Causa Humana Ouro Preto Brazil Institute of Computer Science Universidade Federal Fluminense Niterói Brazil

Control lops are nowadays everywhere, from tiny devices to robust industrial applications. However, even when only few parameters are being dealt, manually fine-tuning has been shown to be a meticulous task for achieving designers’ desired performance. Fine-tuning a controller parameters is an arduous job that requests expertise of the domain. On the other hand, metaheuristics have been barely applied for accomplishing this task. In particular, due to different behaviors that a control loop can have, a multi-objective analysis shows up as essential. In this work, we apply a Multi-Objective Variable Neighborhood Search based algorithm for assisting the design of a Buck Converter, integrating the optimization process with an evaluation mechanism integrated with a circuit simulation software. The obtained Pareto Front presented various response behaviors, optimizing different desired characteristics. We suggest that the proposed framework is a promising tool for assisting decision makers to design more efficient and dynamic systems. © 2018 Elsevier B.V.

关键词： Automatic circuit design Metaheuristics MOVNS Non-dominated control models Optimal Design

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Rainfall forecasting using PSPline and rice production with ocean-atmosphere interaction 2

Rainfall forecasting using PSPline and rice production with ...

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2nd International Conference on Eco engineering Development 2018, ICEED 2018

作者： Caraka, Rezzy Eko Supatmanto, Budi Darmawan Tahmid, Muhammad Soebagyo, Joko Mauludin, M. Ali Iskandar, Akbar Pardamean, Bens Bina Nusantara University Jakarta11480 Indonesia Indonesia Indonesia Agency for Meteorology Climatology and Geophysics Indonesia College of Technology Wastukancana Purwakarta Indonesia Laboratory of Sociology and Extension Padjadjaran University Indonesia Informatics Engineering STMIK AKBA Makassar Indonesia Computer Science Department BINUS Graduate Program - Master of Computer Science Bina Nusantara University Jakarta11480 Indonesia

The role of climate can be affected by plants. The weather can accelerate and multiply the existence of various plant pests and diseases, accelerate the growth and development of grass among plants, and encourage the emergence of infection and significant damage to plants. The elements of climate that affect the growth of plants are one of them is rainfall. In this paper, we performed the simulation using the non-parametric penalized spline (PSPLINE) method and studied the effect on rice production in Lampung. It can be concluded that the increasing fluctuation, frequency, and intensity of climate anomalies in the last decade caused by the ENSO phenomenon have an impact on changes in distribution patterns, intensity, and period of the wet season so that the start of the rainy season and the dry season becomes too late. As a result, there is a seasonal shift from normal average conditions that can ultimately have severe implications for food crops. In a nutshell penalized spline gives high accuracy with R 2 = 96.227% and MAPE = 1.62%. © 2018 Institute of Physics Publishing. All rights reserved.

关键词： Rain

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Concentric Micromirror Array for High-Speed Optical Dynamic Focusing

Concentric Micromirror Array for High-Speed Optical Dynamic ...

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IEEE/LEOS International Conference on Optical MEMS

作者： Nathan Tessema Ersumo Cem Yalcin Nicolas Pégard Laura Waller Daniel Lopez Rikky Muller San Francisco Graduate Program in Bioengineering University of California Berkeley - University of California USA Departement of Electrical Engineering & Computer Sciences University of California Berkeley USA Department of Applied Physical Sciences University of North Carolina at Chapel Hill Chapel Hill USA Center for Nanoscale Materials Argonne National Laboratory Argonne USA

Optical dynamic focusing has emerged as a speed, complexity and efficiency bottleneck across various applications, which include scanning multi-photon microscopy in biology, maskless lithography and micromachining in material processing, and wavefront correction. Here, we present a 32-ring 23,852-pixel concentric micromirror array capable of performing dynamic focusing for wavelengths of up to 1040 nm with a response rate of up to 8.75 kHz, 30 V drive and a focusing full-width-half-maximum to range ratio of 4.8%.

关键词： Optimized production technology High-speed optical techniques Micromechanical devices Nanophotonics Micromirrors Focusing

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Coupling rendering and generative adversarial networks for artificial SAS image generation

arXiv

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arXiv 2019年

作者： Reed, Albert Gerg, Isaac D. McKay, John D. Brown, Daniel C. Williams, David P. Jayasuriya, Suren School of Electrical Computer & Energy Engineering Arizona State University TempeAZ United States School of Arts Media & Engineering Arizona State University TempeAZ United States Applied Research Laboratory Pennsylvania State University State College PA United States Graduate Program in Acoustics Pennsylvania State University State College PA United States School of Electrical Engineering and Computer Science Pennsylvania State University State College PA United States NATO STO Centre for Maritime Research & Experimentation La Spezia Italy

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Re-framing and reimagining the doctoral student narrative: Black women's experiences in engineering and computer science 125

Re-framing and reimagining the doctoral student narrative: B...

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125th ASEE Annual Conference and Exposition

作者： Artis, Sharnnia Subbian, Vignesh Shavers, Marjorie C. Le Sure, Stade Spencer, Breauna Marie Joshi, Aishwarya P. School of Information and Computer Sciences University of California Irvine United States Heidelberg University Department of Graduate Studies in Counseling Germany American Society for Engineering Education Utah State University United States University of California Irvine United States Heidelberg University Clinical Counseling Program Germany

Recent data reveal that a higher percentage of Black women (9.7%) are enrolled in college than any other group, topping Asian women (8.7%), White women (7.1%) and White men (6.1%). Despite these gains in college attendance, Black women are often underrepresented in the fields of engineering and computer science. This paper presents the findings from a qualitative study that investigated the identity and experiences of Black women who are pursuing doctoral degrees in engineering and computer science. This research is grounded on the tenet that one cannot effectively serve or impact a community until he/she genuinely understands the issues and challenges facing the people who are its members. This work explores how Black female doctoral students persist in environments where they are grossly underrepresented. Content analysis is used to examine interview data obtained from 13 Black women who are pursing doctoral degrees in engineering and computer science. This paper concludes with some of the key challenges these women face in their programs on a daily basis. The goal of this research is to bring awareness to not only the challenges, but also potential strategies to increase the retention and persistence of Black women in engineering and computer science across all academic levels. © American Society for engineering Education, 2018.

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