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arXiv 2025年

作者： Larsen, Alexander Swaby, Tera N. Kobulnicky, Henry A. Cañas, Caleb I. Kanodia, Shubham Libby-Roberts, Jessica Monson, Andrew Gupta, Arvind Cochran, William Mahadevan, Suvrath Bender, Chad Diddams, Scott A. Halverson, Samuel Lin, Andrea S.J. Moe, Maxwell Ninan, Joe Robertson, Paul Roy, Arpita Schwab, Christian Stefansson, Gudmundur Department of Physics & Astronomy University of Wyoming LaramieWY82070 United States NASA Goddard Space Flight Center 8800 Greenbelt Road GreenbeltMD20771 United States Earth and Planets Laboratory Carnegie Institution for Science 5241 Broad Branch Road NW WashingtonDC20015 United States Department of Astronomy & Astrophysics The Pennsylvania State University 525 Davey Laboratory University ParkPA16802 United States Center for Exoplanets and Habitable Worlds The Pennsylvania State University 525 Davey Laboratory University ParkPA16802 United States Steward Observatory The University of Arizona 933 N. Cherry Avenue TucsonAZ85721 United States U.S. National Science Foundation National Optical-Infrared Astronomy Research Laboratory 950 N. Cherry Ave. TucsonAZ85719 United States McDonald Observatory Department of Astronomy The University of Texas Austin United States Center for Planetary Systems Habitability The University of Texas Austin United States Electrical Computer & Energy Engineering University of Colorado 1111 Engineering Dr. BoulderCO80309 United States Department of Physics University of Colorado 2000 Colorado Avenue BoulderCO80309 United States Jet Propulsion Laboratory 4800 Oak Grove Drive PasadenaCA91109 United States Department of Astronomy California Institute of Technology 1200 E California Blvd PasadenaCA91125 United States Department of Astronomy and Astrophysics Tata Institute of Fundamental Research Homi Bhabha Road Colaba Mumbai400005 India Department of Physics & Astronomy The University of California Irvine IrvineCA92697 United States Astrophysics & Space Institute Schmidt Sciences New YorkNY10011 United States School of Mathematical and Physical Sciences Macquarie University Balaclava Road North RydeNSW2109 Australia Anton Pannekoek Institute for Astronomy University of Amsterdam Science Park 904 Amsterdam1098 XH Netherlands

Brown dwarfs bridge the gap between stars and planets, providing valuable insight into both planetary and stellar formation mechanisms. Yet the census of transiting brown dwarf companions, in particular around M dwarf stars, remains incomplete. We report the discovery of two transiting brown dwarfs around low-mass hosts using a combination of space- and ground-based photometry along with near-infrared radial velocities. We characterize TOI-5389Ab (68.0+2−2.22 MJ) and TOI-5610b (40.4+1−1.00 MJ), two moderately massive brown dwarfs orbiting early M dwarf hosts (Teff = 3569±59 K and 3618±59 K, respectively). For TOI-5389Ab, the best fitting parameters are period P = 10.40046 ± 0.00002 days, radius RBD = 0.824+0−0.033031 RJ, and low eccentricity e = 0.0962+0−0.00270046. In particular, this constitutes one of the most extreme substellar-stellar companion-to-host mass ratios of q = 0.150. For TOI-5610b, the best fitting parameters are period P = 7.95346 ± 0.00002 days, radius RBD = 0.887+0−0.031031 RJ, and moderate eccentricity e = 0.354+0−0.011012. Both targets are expected to have shallow but potentially observable secondary transits: 500 ppm in Johnson K band for both. A statistical analysis of M-dwarf/BD systems reveals for the first time that those at short orbital periods (P J BD J companions (q © 2025, CC0.

关键词： Stars

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Noise-enabled species recovery in the aftermath of a tipping point

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Physical Review E 2020年第1期101卷 012206-012206页

作者： Yu Meng Junjie Jiang Celso Grebogi Ying-Cheng Lai Institute for Complex Systems and Mathematical Biology School of Natural and Computing Sciences King's College University of Aberdeen Aberdeen AB24 3UE United Kingdom School of Electrical Computer and Energy Engineering Arizona State University Tempe Arizona 85287 USA Department of Physics Arizona State University Tempe Arizona 85287 USA

The beneficial role of noise in promoting species coexistence and preventing extinction has been recognized in theoretical ecology, but previous studies were mostly concerned with low-dimensional systems. We investigate the interplay between noise and nonlinear dynamics in real-world complex mutualistic networks with a focus on species recovery in the aftermath of a tipping point. Particularly, as a critical parameter such as the mutualistic interaction strength passes through a tipping point, the system collapses and approaches an extinction state through a dramatic reduction in the species populations to near-zero values. We demonstrate the striking effect of noise: when the direction of parameter change is reversed through the tipping point, noise enables species recovery which otherwise would not be possible. We uncover an algebraic scaling law between the noise amplitude and the parameter distance from the tipping point to the recovery point and provide a physical understanding through analyzing the nonlinear dynamics based on an effective, reduced-dimension model. Noise, in the form of small population fluctuations, can thus play a positive role in protecting high-dimensional, complex ecological networks.

关键词： Bifurcations Dynamics of networks Noise Population dynamics Ecological networks

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From multi-modal property dataset to robot-centric conceptual knowledge about household objects

arXiv

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arXiv 2019年

作者： Thosar, Madhura Mueller, Christian A. Jaeger, Georg Schleiss, Johannes Pulugu, Narender Chennaboina, Ravi Mallikarjun Jeevangekar, Sai Vivek Birk, Andreas Pfingsthorn, Max Zug, Sebastian Institute for Intelligent Cooperating Systems Faculty of Computer Science Otto-von-Guericke University Magdeburg Germany Robotics Computer Science & Electrical Engineering Department Jacobs University Bremen Germany Institute for Computer Science Technische Universität Bergakademie Freiberg Germany OFFIS Institute for Information Technology Oldenburg Germany

Tool-use applications in robotics require conceptual knowledge about objects for informed decision making and object interactions. State-of-the-art methods employ hand-crafted symbolic knowledge which is defined from a human perspective and grounded into sensory data afterwards. However, due to different sensing and acting capabilities of robots, their conceptual understanding of objects must be generated from a robot's perspective entirely, which asks for robot-centric conceptual knowledge about objects. With this goal in mind, this article motivates that such knowledge should be based on physical and functional properties of objects. Consequently, a selection of ten properties is defined and corresponding extraction methods are proposed. This multi-modal property extraction forms the basis on which our second contribution, a robot-centric knowledge generation is build on. It employs unsupervised clustering methods to transform numerical property data into symbols, and Bivariate Joint Frequency Distributions and Sample Proportion to generate conceptual knowledge about objects using the robot-centric symbols. A preliminary implementation of the proposed framework is employed to acquire a dataset comprising physical and functional property data of 110 houshold objects. This Robot-Centric dataSet (RoCS) is used to evaluate the framework regarding the property extraction methods, the semantics of the considered properties within the dataset and its usefulness in real-world applications such as tool substitution. Copyright © 2019, The Authors. All rights reserved.

关键词： Decision making

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Implementation of Consensus-ADMM Approach for Fast DC-OPF Studies

Implementation of Consensus-ADMM Approach for Fast DC-OPF St...

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International Conference on Smart Energy systems and Technologies (SEST)

作者： Mohammad Javadi Ali Esmaeel Nezhad Matthew Gough Mohamed Lotfi João P.S. Catalão Institute for Systems and Computer Engineering Technology and Science (INESC TEC) Porto Portugal Department of Electrical Electronic and Information Engineering University of Bologna Italy

This paper proposes a novel method for solving the Optimal Power Flow (OPF) problem in conditions close to realtime. The linearized cost function of the generating units is used to this end. Besides, the presented linear model is solved using the Consensus Alternating Direction Method of Multipliers (C-ADMM) approach. This technique would provide the possibility of modeling the problem both in centralized and decentralized manners. The suggested method exploits the power flow results obtained from the previous iteration to considerably improve the rate of convergence. As the C-ADMM method uses an iterative technique, Lagrange multipliers, and the norm function, the rate of convergence highly depends upon assigning the initial conditions and the optimality gap. Thus, using the operating points of the previous instant due to being close to the operating point of the current instant would enhance the results. The proposed model has been implemented on two case studies including the Pennsylvania-New Jersey-Maryland (PJM) network to verify the results and the 9-bus system to evaluate the performance of the model for the daily operation.

关键词： Load flow Convergence Linear programming Cost function Power transmission lines

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MEMS-actuated Metasurface Alvarez Lens

arXiv

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arXiv 2020年

作者： Han, Zheyi Colburn, Shane Majumdar, Arka Böhringer, Karl Department of Electrical and Computer Engineering University of Washington SeattleWA98195 United States Department of Physics University of Washington SeattleWA98195 United States Department of Bioengineering University of Washington SeattleWA98195 United States Institute for Nano-engineered Systems University of Washington Washington98195 United States

Miniature lenses with tunable focus are essential components for many modern applications involving compact optical systems. While several tunable lenses have been reported with various tuning mechanisms, they often still face challenges in power consumption, tuning speed, fabrication cost, or production scalability. In this work, we have adapted the mechanism of an Alvarez lens – a varifocal composite lens in which lateral shifts of two optical elements with cubic phase surfaces give rise to a change in optical power – to construct a miniature, MEMS-actuated metasurface Alvarez lens. The implementation based on electrostatic microelectromechanical systems (MEMS) generates fast and controllable actuation with low power consumption. The utilization of metasurfaces, ultrathin and subwavelength-patterned diffractive optics, as the optical elements greatly reduces the device volume compared to systems using conventional freeform lenses. The entire MEMS Alvarez metalens is fully compatible with modern semiconductor fabrication technologies, granting it the potential to be mass-produced at a low unit cost. In the reported prototype to operate at 1550 nm wavelength, a total uniaxial displacement of 6.3 µm is achieved in the Alvarez metalens with direct-current (DC) voltage application up to 20 V, modulating the focal position within a total tuning range of 68 µm, producing more than an order of magnitude change in focal length and 1460 diopters change in optical power. The MEMS Alvarez metalens has a robust design that can potentially generate a much larger tuning range without substantially increasing device volume or energy consumption, making it desirable for a wide range of imaging and display applications. Copyright © 2020, The Authors. All rights reserved.

关键词： Electromechanical devices

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Cooperative schedule-driven intersection control with connected and autonomous vehicles

arXiv

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arXiv 2019年

作者： Hu, Hsu-Chieh Smith, Stephen F. Goldstein, Rick Department of Electrical and Computer Engineering Carnegie Mellon University PittsburghPA United States Robotics Institute School of Computer Science Carnegie Mellon University PittsburghPA United States

Recent work in decentralized, schedule-driven traffic control has demonstrated the ability to improve the efficiency of traffic flow in complex urban road networks. In this approach, a scheduling agent is associated with each intersection. Each agent senses the traffic approaching its intersection and in real-time constructs a schedule that minimizes the cumulative wait time of vehicles approaching the intersection over the current look-ahead horizon. In this paper, we propose a cooperative algorithm that utilizes both connected and autonomous vehicles (CAV) and schedule-driven traffic control to create better traffic flow in the city. The algorithm enables an intersection scheduling agent to adjust the arrival time of an approaching platoon through use of wireless communication to control the velocity of vehicles. The sequence of approaching platoons is thus shifted toward a new shape that has smaller cumulative delay. We demonstrate how this algorithm outperforms the original approach in a real-time traffic signal control problem. Copyright © 2019, The Authors. All rights reserved.

关键词： Autonomous vehicles

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K-Means clustering on noisy intermediate scale quantum computers

arXiv

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arXiv 2019年

作者： Khan, Sumsam Ullah Awan, Ahsan Javed Vall-Llosera, Gemma Department of Cloud Systems and Platforms Ericsson Research Sweden School of Electrical Engineering and Computer Science Royal Institute of Technology Sweden

Real-Time clustering of big performance data generated by the telecommunication networks requires domain-specific high performance compute infrastructure to detect anomalies. In this paper, we evaluate noisy intermediate-scale quantum (NISQ) computers characterized by low decoherence times, for K-means clustering and propose three strategies to generate shorter-depth quantum circuits needed to overcome the limitation of NISQ computers. The strategies are based on exploiting;i) quantum interference, ii) negative rotations and iii) destructive interference. By comparing our implementations on IBMQX2 machine for representative data sets, we show that NISQ computers can solve the K-means clustering problem with the same level of accuracy as that of classical computers. Copyright © 2019, The Authors. All rights reserved.

关键词： Qubits

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QoS-Aware Power Management with Deep Learning

QoS-Aware Power Management with Deep Learning

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IFIP/IEEE International Symposium on Integrated Network Management

作者： Junxiu Zhou Xian Liu Yangyang Tao Shucheng Yu Department of Systems Engineering University of Arkansas at Little Rock Little Rock USA Department of Electrical and Computer Engineering Stevens Institute of Technology New Jersey USA

ISBN: (纸本)9781728106182;9783903176157

Network densification is becoming an overwhelming phenomenon in many emerging wireless communication paradigms. Although network densification may promote system metrics like the throughputs, the quality-of-service (QoS) issue needs to be carefully investigated. Commonly, the QoS-aware power management is tightly restricted by the complicated patterns of interferences among multiple active communication devices. Conventional approaches in optimizing the QoS-aware power management problem may either fail to convergence or the overall power rate is unsatisfactory. In this paper, we make an effort to solve the QoS-aware power management problem with the aid of the deep learning (DL) methodology. Recently DL has shone light on wide variety of research fields, such as image processing and natural language processing. It is our intensive interest in exploring the role that DL plays to solve the QoS-aware power management problem. In the presented extensive experimental analysis work, we show that the DL-based method can well match the solution generated by a conventional optimization procedure. It is impressed that the convergence of DL is quite fast. Moreover, the DL-based approach demonstrates the better performance when the conventional method enters the infeasible region.

关键词： Quality of service Power system management Artificial neural networks Computational modeling Interference Wireless communication Resource management

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Hybrid Robust Optimal Resource Allocation with Momentum

Hybrid Robust Optimal Resource Allocation with Momentum

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IEEE Annual Conference on Decision and Control

作者： Daniel E. Ochoa Jorge I. Poveda Cesar A. Uribe Nicanor Quijano Department of Electrical Computer and Energy Engineering at the University of Colorado Boulder Laboratory for Information and Decision Systems Massachusetts Institute of Technology Department of Electronics and Electrical Engineering University of Los Andes Bogota Colombia

ISBN: (数字)9781728113982

ISBN: (纸本)9781728113999

We study the problem of robust resource allocation with momentum following a dynamical systems point of view. Motivated by a class of existing optimization dynamics with no momentum defined on the general m-simplex, we propose a class of time-varying differential equations with momentum that achieve acceleration and preserve most of the asymptotic properties of its time-invariant counterpart. Since time-varying dynamics with momentum in continuous-time usually lack of structural robustness properties, we present a hybrid regularization that induces the property of uniform asymptotic stability in the system. We show this by using the invariance principle for well-posed hybrid dynamical systems, and we establish the existence of strictly positive margins of robustness with respect to arbitrarily small disturbances. We illustrate our results via numerical simulations.

关键词： Robustness Acceleration Resource management Asymptotic stability Mathematical model Cost function

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Observation of Quantized Exciton Energies in Monolayer WSe2 under a Strong Magnetic Field

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Physical Review X 2020年第2期10卷 021024-021024页

作者： Tianmeng Wang Zhipeng Li Zhengguang Lu Yunmei Li Shengnan Miao Zhen Lian Yuze Meng Mark Blei Takashi Taniguchi Kenji Watanabe Sefaattin Tongay Wang Yao Dmitry Smirnov Chuanwei Zhang Su-Fei Shi Department of Chemical and Biological Engineering Rensselaer Polytechnic Institute Troy New York 12180 USA National High Magnetic Field Lab Tallahassee Florida 32310 USA Department of Physics Florida State University Tallahassee Florida 32306 USA Department of Physics The University of Texas at Dallas Richardson Texas 75080 USA National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan School for Engineering of Matter Transport and Energy Arizona State University Tempe Arizona 85287 USA Department of Physics and Center of Theoretical and Computational Physics University of Hong Kong Hong Kong China Department of Electrical Computer & Systems Engineering Rensselaer Polytechnic Institute Troy New York 12180 USA

Quantized energy levels are one of the hallmarks of quantum mechanics at the atomic level. The manifestation of quantization in macroscopic physical systems has showcased important quantum phenomena, such as quantized conductance in (fractional) quantum Hall effects and quantized vortices in superconductors. Here we report the first experimental observation of quantized exciton energies in a macroscopic system with strong Coulomb interaction, monolayer WSe2 crystal under a strong magnetic field. Employing helicity-resolved magnetoreflectance spectroscopy, we observe a striking ladder of plateaus as a function of the gate voltage for both exciton resonance in one valley and exciton-polariton branch in the opposite valley, thanks to the inter-Landau levels transitions governed by unique valley-selective selection rules. The observed quantized excitation energy level spacing sensitively depends on the doping level, indicating strong many-body effects. Our work will inspire the study of intriguing quantum phenomena originating from the interplay between Landau levels and many-body interactions in two-dimension monolayer crystals.

关键词： Excitons Polarons 2-dimensional systems Transition metal dichalcogenides Reflectivity

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