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Stability of a giant connected component in a complex network

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Physical Review E 2018年第1期97卷 012309-012309页

作者： Maksim Kitsak Alexander A. Ganin Daniel A. Eisenberg Pavel L. Krapivsky Dmitri Krioukov David L. Alderson Igor Linkov Department of Physics Northeastern University 110 Forsyth Street 111 Dana Research Center Boston Massachusetts 02115 USA. University of Virginia Department of Systems and Information Engineering Charlottesville Virginia 22904 USA U.S. Army Engineer Research and Development Center Contractor Concord Massachusetts 01742 USA School of Sustainable Engineering and the Built Environment Arizona State University Tempe Arizona 85281 USA Department of Physics Boston University Boston Massachusetts 02215 USA Departments of Physics Mathematics and Electrical and Computer Engineering Northeastern University Boston Massachusetts 02115 USA Operations Research Department Naval Postgraduate School Monterey California 93943 USA U.S. Army Engineer Research and Development Center Environmental Laboratory Concord Massachusetts 01742 USA

We analyze the stability of the network's giant connected component under impact of adverse events, which we model through the link percolation. Specifically, we quantify the extent to which the largest connected component of a network consists of the same nodes, regardless of the specific set of deactivated links. Our results are intuitive in the case of single-layered systems: the presence of large degree nodes in a single-layered network ensures both its robustness and stability. In contrast, we find that interdependent networks that are robust to adverse events have unstable connected components. Our results bring novel insights to the design of resilient network topologies and the reinforcement of existing networked systems.

关键词： Cascades Random attacks Robustness Topological tools

Keep Your Friends Close and Your Colleagues Nearby: The Hidden Ties That Improve STEM Education

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Change 2019年第1期51卷 42页

作者： Mestre, Jose P. Herman, Geoffrey L. Tomkin, Jonathan H. West, Matthew Jose P. Mestre (mestre@illinois.edu). A theoretical nuclear physicist by training Mestre’s research focuses on the learning of physics contributing in areas such as the acquisition and use of knowledge by experts and novices transfer of learning problem solving and instructional design. He has offered Congressional testimony on The Science of Learning has published numerous articles and books and is a Fellow of the American Physical Society.http://***/0000-0003-2110-1954 Geoffrey L. Herman (glherman@illinois.edu). Herman has a Ph.D. in Electrical and Computer Engineering and is a Teaching Assistant Professor in Computer Science and a Research Assistant Professor in the Department of Curriculum & Instruction at the University of Illinois. His research focuses on how students learn engineering and computing concepts and studying processes for creating systemic instructional change in college settings. Previously he was a postdoctoral researcher in Engineering Education at Purdue University.http://***/0000-0002-9501-2295 Jonathan H. Tomkin (tomkin@illinois.edu). Tomkin is a mathematically based geoscientist with two research focus areas: first he uses models and large data sets to determine how climates glaciers tectonics and landscapes interact. Second he explores how new technological and organizational approaches can improve STEM education. He produced the first geoscience MOOC is the editor of an open-source textbook and has published widely in both geoscience and STEM education. Matthew West (mwest@illinois.edu). Matthew West is an Associate Professor of Mechanical Science and Engineering at the University of Illinois with research interests in scientific computing that include time integration of deterministic and stochastic systems distributed computation and particle methods for simulation and estimation. In education he researches computer-based assessment and the development of innovative teaching cultures. Professor West is a University of Illinois Distinguished Teacher-Scholar and Colleg

A science department on the campus of the University of Illinois has received numerous national awards for excellence in undergraduate teaching. The secret to their success? For nearly two decades, they have collaboratively used evidence-based instructional practices (EBIP) in their introductory level courses. Despite these successes and efforts to spread their EBIP, no other departments followed this department's lead. Then, suddenly six years ago, many instructors from other departments began adopting EBIP in their classrooms. This article asks what was the catalyst for this change? Why had previous attempts at institutional change failed? The authors answer these questions by analyzing their efforts to transform the teaching practices in large-enrollment science and engineering introductory courses on their campus.

关键词： STEM Education Evidence Based Practice Teaching Methods Undergraduate Study College Faculty Educational Change Communities of Practice Mentors School CultureIllinois

Gradient methods for submodular maximization

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arXiv 2017年

作者： Hassani, Hamed Soltanolkotabi, Mahdi Karbasi, Amin Department of Electrical and Systems Engineering University of Pennsylvania PhiladelphiaPA United States Ming Hsieh Department of Electrical Engineering University of Southern California Los AngelesCA United States Departments of Electrical Engineering and Computer Science Yale University New HavenCT United States

In this paper, we study the problem of maximizing continuous submodular functions that naturally arise in many learning applications such as those involving utility functions in active learning and sensing, matrix approximations and network inference. Despite the apparent lack of convexity in such functions, we prove that stochastic projected gradient methods can provide strong approximation guarantees for maximizing continuous submodular functions with convex constraints. More specifically, we prove that for monotone continuous DR-submodular functions, all fixed points of projected gradient ascent provide a factor 1/2 approximation to the global maxima. We also study stochastic gradient and mirror methods and show that after O(1/ϵ2) iterations these methods reach solutions which achieve in expectation objective values exceeding (OPT2 − ϵ). An immediate application of our results is to maximize submodular functions that are defined stochastically, i.e. the submodular function is defined as an expectation over a family of submodular functions with an unknown distribution. We will show how stochastic gradient methods are naturally well-suited for this setting, leading to a factor 1/2 approximation when the function is monotone. In particular, it allows us to approximately maximize discrete, monotone submodular optimization problems via projected gradient descent on a continuous relaxation, directly connecting the discrete and continuous domains. Finally, experiments on real data demonstrate that our projected gradient methods consistently achieve the best utility compared to other continuous baselines while remaining competitive in terms of computational effort. Copyright © 2017, The Authors. All rights reserved.

关键词： Gradient methods

Delay-driven layer assignment for advanced technology nodes

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Delay-driven layer assignment for advanced technology nodes

Asia and South Pacific design Automation Conference

作者： Szu-Yuan Han Wen-Hao Liu Rickard Ewetz Cheng-Kok Koh Kai-Yuan Chao Ting-Chi Wang Department of Computer Science National Tsing Hua University Hsinchu Taiwan Block Implementation Cadence Design Systems Austin TX USA Department of Electrical and Computer Engineering University of Central Florida Orlando FL USA School of Electrical and Computer Engineering Purdue University West Lafayette IN USA Intel Corporation Hillsboro OR USA

ISBN: (纸本)9781509015597

This paper addresses a delay-driven layer assignment problem with consideration of via delay and coupling effect in the global routing stage. A negotiation-based framework is proposed to balance delay, congestion, and via count. Coupling capacitance is considered using a probabilistic look-up table. Finally, the proposed algorithm uses both parallel wires and wide wires to reduce wire delay. The effectiveness of our layer assignment algorithm is supported by extensive experimental results.

关键词： Wires Routing Delays Couplings Capacitance Three-dimensional displays Two dimensional displays

Experimental observation of the topological structure of exceptional points in an ultrathin hybridized metamaterial

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Physical Review A 2017年第6期96卷 063823-063823页

作者： Ming Kang Weiren Zhu Ivan D. Rukhlenko College of Physics and Materials Science Tianjin Normal University Tianjin 300387 China Department of Electronic Engineering Shanghai Jiao Tong University Shanghai 200240 China Modeling and Design of Nanostructures Laboratory ITMO University Saint Petersburg 197101 Russia Department of Electrical and Computer Systems Engineering Monash University Clayton Victoria 3800 Australia

The exceptional point (EP), which is one of the most important branch-type singularities exclusive to non-Hermitian systems, has been observed recently in various synthetic materials, giving rise to counterintuitive phenomena due to the nontrivial topology of the EP. Here, we present a direct experimental observation of the topological structure of the EPs via the angle-resolved transmission measurement of a hybridized metamaterial. Both eigenvalues and eigenvectors show branch-point singularities in the investigated biparametric space of frequency and incident angle. Importantly, the angle-resolved transmission coefficients provide all the information about the eigenvalues as well as the corresponding eigenvectors in the biparametric space, revealing the nontrivial topological structure of the EP, such as mode switching and the topological phase for a parameter loop encircling the EP. It is shown that the appearance of the EP in the scattering matrix is related directly to the perfect unidirectional transmission and the chirality of the EP corresponds to the maximum or minimum value of the asymmetric factor. Our investigation uncovers the capabilities of metamaterials for exploring the physics of EPs and their potential for having extreme optical properties, which provide potential applications in the spectral band ranging from microwaves to visible frequencies.

关键词： Metamaterials

On the role of theory and modeling in neuroscience

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arXiv 2020年

作者： Levenstein, Daniel Alvarez, Veronica A. Amarasingham, Asohan Azab, Habiba Chen, Zhe S. Gerkin, Richard C. Hasenstaub, Andrea Iyer, Ramakrishnan Jolivet, Renaud B. Marzen, Sarah Monaco, Joseph D. Prinz, Astrid A. Quraishi, Salma Santamaria, Fidel Shivkumar, Sabyasachi Singh, Matthew F. Traub, Roger Rotstein, Horacio G. Nadim, Farzan Redish, A. David Montreal Neurological Institute McGill University MontrealQC Canada Laboratory on Neurobiology of Compulsive Behaviors National Institute on Alcohol Abuse and Alcoholism NIH BethesdaMD United States Department of Neuroscience Center for Magnetic Resonance Research University of Minnesota MinneapolisMN United States School of Life Sciences Arizona State University TempeAZ United States Department of Otolaryngology - Head and Neck Surgery University of California San Francisco San FranciscoCA United States Allen Institute for Brain Science SeattleWA United States Maastricht University Maastricht Netherlands Department of Biomedical Engineering Johns Hopkins University School of Medicine BaltimoreMD United States Department of Biology University of Texas at San Antonio San AntonioTX United States Department of Psychological & Brain Sciences Department of Electrical & Systems Engineering Washington University in St. Louis St. LouisMO United States IBM T.J. Watson Research Center AI Foundations Yorktown HeightsNY United States W. M. Keck Science Department Pitzer Scripps and Claremont McKenna Colleges ClaremontCA United States Department of Biology Emory University AtlantaGA United States Department of Mathematics City College of New York United States Departments of Biology Computer Science and Psychology The Graduate Center City University of New York United States Brain and Cognitive Sciences University of Rochester RochesterNY United States Federated Department of Biological Sciences New Jersey Institute of Technology Rutgers University Institute for Brain and Neuroscience Research New Jersey Institute of Technology NewarkNJ United States Department of Neuroscience University of Minnesota MinneapolisMN United States Department of Psychiatry Neuroscience & Physiology New York University School of Medicine United States Mila - Quebec AI Institute MontrealQC Canada

In recent years, the field of neuroscience has gone through rapid experimental advances and a significant increase in the use of quantitative and computational methods. This growth has created a need for clearer analyses of the theory and modeling approaches used in the field. This issue is particularly complex in neuroscience because the field studies phenomena that cross a wide range of scales and often require consideration at varying degrees of abstraction, from precise biophysical interactions to the computations they implement. We argue that a pragmatic perspective of science, in which descriptive, mechanistic, and normative models and theories each play a distinct role in defining and bridging levels of abstraction will facilitate neuroscientific practice. This analysis leads to methodological suggestions, including selecting a level of abstraction that is appropriate for a given problem, identifying transfer functions to connect models and data, and the use of models themselves as a form of experiment. © 2020, CC BY.

关键词： Computation theory

Position-based power allocation for uplink HSRs wireless communication when two trains encounter 59

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Position-based power allocation for uplink HSRs wireless com...

59th IEEE Global Communications Conference, GLOBECOM 2016

作者： Li, Tao Chen, Zhengchuan Fan, Pingyi Letaief, Khaled Ben Department of Electronic Engineering Tsinghua University Beijing China Information Systems Technology and Design Pillar SUTD Singapore Department of Electrical and Computer Engineering HKUST Hong Kong

Highly mobile wireless communication attracts much more attention currently due to the rapid development of high speed railways (HSRs) all over the world. Although the single train scenario has been well studied by now, two trains encountering scenario over the general two-way railways is also an important problem deserving to investigate. To this end, this paper concentrates on the uplink information transmission of HSRs in the two trains encountering scenario, which is modeled as a time- varying partial multiple access channel. In order to evaluate the transmission performance, the achievable rate region is utilized as a metric to characterize the tradeoff between the rates that each train can obtain under limited channel source constraint. With the help of superposition modulation and sequential interference cancelling, an optimal adaptive power allocation scheme aided by real-time position information is proposed to achieve the maximal boundary of the achievable rate region, namely alleviating the effect of encountering on information transmission to the largest extent. According to the numerical results, great improvement can be obtained by new proposed adaptive power allocation along time. © 2016 IEEE.

关键词： Railroad transportation

Constraining attacker capabilities through actuator saturation

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arXiv 2017年

作者： Kafash, Sahand Hadizadeh Giraldo, Jairo Murguia, Carlos Cardenas, Alvaro A. Ruths, Justin Departments of Mechanical and Systems Engineering University of Texas at Dallas RichardsonTX United States Computer Science Department University of Texas at Dallas RichardsonTX United States iTrust Center Singapore University of Technology and Design Singapore Singapore

For LTI control systems, we provide mathematical tools - in terms of Linear Matrix Inequalities - for computing outer ellipsoidal bounds on the reachable sets that attacks can induce in the system when they are subject to the physical limits of the actuators. Next, for a given set of dangerous states, states that (if reached) compromise the integrity or safe operation of the system, we provide tools for designing new artificial limits on the actuators (smaller than their physical bounds) such that the new ellipsoidal bounds (and thus the new reachable sets) are as large as possible (in terms of volume) while guaranteeing that the dangerous states are not reachable. This guarantees that the new bounds cut as little as possible from the original reachable set to minimize the loss of system performance. computer simulations using a platoon of vehicles are presented to illustrate the performance of our tools. Copyright © 2017, The Authors. All rights reserved.

关键词： Linear matrix inequalities

Human and smart machine co-learning with brain computer interface

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arXiv 2018年

作者： Lee, Chang-Shing Wang, Mei-Hui Ko, Li-Wei Prof, Naoyuki Kubota Lin, Lu-An Kitaoka, Shinya Wang, Yu-Te Su, Shun-Feng Computer Science and Information Engineering National Cheng Kung University Tainan Taiwan Taiwan National Chiao Tung University Hsinchu Taiwan Institute of Bioinformatics and Systems Biology National Chiao Tung University Taiwan Nagoya University Nagoya Japan Department of System Design Tokyo Metropolitan University Tokyo Japan OASE Lab. NUTN Taiwan Dwango Media Village DWANGO Co. Ltd. Japan La Jolla Swartz Center for Computational Neuroscience UCSD United States Purdue University West LafayetteIN United States Department of Electrical Engineering National Taiwan University of Science and Technology Taiwan

Machine learning has become a very popular approach for cybernetics systems, and it has always been considered important research in the Computational Intelligence area. Nevertheless, when it comes to smart machines, it is not just about the methodologies. We need to consider systems and cybernetics as well as include human in the loop. The purpose of this article is as follows: (1) To integrate the open source Facebook AI Research (FAIR) DarkForest program of Facebook with Item Response Theory (IRT), to the new open learning system, namely, DDF learning system;(2) To integrate DDF Go with Robot namely Robotic DDF Go system;(3) To invite the professional Go players to attend the activity to play Go games on site with a smart machine. The research team will apply this technology to education, such as, playing games to enhance the children concentration on learning mathematics, languages, and other topics. With the detected brainwaves, the robot will be able to speak some words that are very much to the point for the students and to assist the teachers in classroom in the future. Copyright © 2018, The Authors. All rights reserved.

关键词： Social networking (online)