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Annual IEEE Conference on Applied Power Electronics Conference and Exposition (APEC)

作者： Bilal Akin Seung-deog Choi Mina M. Rahimian Hamid A. Toliyat C2000 Systems & Applications Group Texas Instruments Inc. Stafford TX USA Advanced Electric Machines & Power Electronics Laboratory Department of Electrical & Computer Engineering Texas A and M University College Station TX USA

The reference frame theory constitutes an essential aspect of electric machine analysis and control. In this study, apart from the conventional applications, it is reported that the reference frame theory approach (RFTA) can successfully be applied to real time fault diagnosis of electric machinery systems as a powerful tool to find the magnitude and phase quantities of fault signatures with good precision. Although it is possible to run RFTA for each fault signature consecutively, orthogonal PN (Pseudo Noise) code is proposed as an alternative method to detect more than one fault simultaneously. As the physical facts explaining the incipient fault mechanisms are studied for a long time, the motor fault signature frequencies and fault models are very well-known. Therefore, ignoring all other components, the proposed method focuses only on certain fault signatures in the current spectrum depending on the examined motor fault. Broken rotor bar and eccentricity faults are experimentally tested employing the TMS320F2812 digital signal processor (DSP) to prove the effectiveness of the proposed method. In this application, only the readily available drive hardware is used without employing additional components such as analog filters, signal conditioning board, external sensors, etc. The motor drive on-board DSP is utilized both for motor control and fault detection purposes providing instantaneous fault information. Being a model independent fault analyzer, this method can be applied to all multi-phase and single phase motors.

关键词： Digital signal processing Monitoring Motor drives Electric machines Real time systems Fault diagnosis Machinery electrical fault detection Frequency Rotors

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Technical report: Sensor-based reactive symbolic planning in partially known environments

arXiv

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arXiv 2017年

作者： Vasilopoulos, Vasileios Vega-Brown, William Arslan, Omur Roy, Nicholas Koditschek, Daniel E. Department of Mechanical Engineering and Applied Mechanics University of Pennsylvania PhiladelphiaPA19104 United States Computer Science and Artificial Intelligence Laboratory Massachusetts Institute of Technology CambridgeMA02139 United States Department of Electrical and Systems Engineering University of Pennsylvania PhiladelphiaPA19104 United States

This paper considers the problem of completing assemblies of passive objects in nonconvex environments, cluttered with convex obstacles of unknown position, shape and size that satisfy a specific separation assumption. A differential drive robot equipped with a gripper and a LIDAR sensor, capable of perceiving its environment only locally, is used to position the passive objects in a desired configuration. The method combines the virtues of a deliberative planner generating high-level, symbolic commands, with the formal guarantees of convergence and obstacle avoidance of a reactive planner that requires little onboard computation and is used online. The validity of the proposed method is verified both with formal proofs and numerical simulations. Copyright © 2017, The Authors. All rights reserved.

关键词： Optical radar

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A real-time maintenance scheduling policy in serial production lines

A real-time maintenance scheduling policy in serial producti...

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World Congress on Intelligent Control and Automation (WCICA)

作者： Lingbo Lu Yang Liu Jingshan Li Cindy Chang Stephan Biller Guoxian Xiao Department of Electrical and Computer Engineering University of Kentucky Lexington KY USA Department of Industrial Engineering University of Louisville Louisville KY USA Department of Industrial and Systems Engineering University of Wisconsin Madison Madison WI USA Department of Mechanical Engineering New York Institute of Technology Old Westbury NY USA Manufacturing Systems Research Laboratory General Motors Research and Development Center Warren MI USA

In this paper, we carry out a simulation study to integrate preventive maintenance scheduling policy with real-time production system analysis and workforce dispatching rule to investigate the impact of such a policy on system productivity. The preventive maintenance is triggered by the threshold of number of breakdowns and current up- and downstream buffer status, with the maintenance workforce being dispatched based on dynamic bottleneck policy. It is shown that the system performance can be improved by implementing such a real-time scheduling policy.

关键词： Electric breakdown

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A 400 MHz, 8-Bit, 1.75-ps Resolution Pipelined-Two-Step Time-to-Digital Converter with Dynamic Time Amplification

A 400 MHz, 8-Bit, 1.75-ps Resolution Pipelined-Two-Step Time...

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IEEE International Symposium on Circuits and systems (ISCAS)

作者： Yuting Tu Rongjin Xu Dawei Ye Liangjian Lyu C.-J. Richard Shi State Key Laboratory of ASIC and System Fudan University Shanghai 201203 China Institute of Brain-inspired Circuits and Systems (iBiCAS) Fudan University Shanghai 201203 China Department of Electrical and Computer Engineering University of Washington Seattle 98195 USA

ISBN: (数字)9781728133201

ISBN: (纸本)9781728133218

This work proposes a high-speed pipelined-two-step time-to-digital converter (TDC) with a dynamic time amplification (DTA) to improve the resolution at low power. The key element of this TDC is the DTA. It samples the residual time errors as voltages held in the MOM capacitors and discharges them to generate the amplified time difference. Thanks to the dynamic time-voltage-time conversion, the DTA realizes high linearity and power efficiency, and can be employed to build a pipeline TDC architecture with high sampling frequency because of its sample and hold operation. Moreover, the DTA maintains constant gain, so only a one-time forground calibration for gain mismatch is required in this TDC. Simulations show that the TDC designed in 65 nm CMOS achieves 8-bit, 1.75 ps of time resolution, and 1 LSB INL and 1.6 LSB DNL with one-time foreground calibration at 400 MHz sampling frequency while just consuming 726 μW power, which corresponds to 18.45 fJ/Conv. FoM.

关键词： Delays Calibration Inverters Capacitors Linearity Tin

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Cyber-Security Knowledge Graph Generation by Hierarchical Nonnegative Matrix Factorization

arXiv

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arXiv 2024年

作者： Barron, Ryan Eren, Maksim E. Bhattarai, Manish Wanna, Selma Solovyev, Nicholas Rasmussen, Kim Alexandrov, Boian S. Nicholas, Charles Matuszek, Cynthia Theoretical Division Los Alamos National Laboratory Los Alamos United States Advanced Research in Cyber Systems Los Alamos National Laboratory Los Alamos United States Department of Computer Science and Electrical Engineering University of Maryland Baltimore CountyMD United States

Much of human knowledge in cybersecurity is encapsulated within the ever-growing volume of scientific papers. As this textual data continues to expand, the importance of document organization methods becomes increasingly crucial for extracting actionable insights hidden within large text datasets. Knowledge Graphs (KGs) serve as a means to store factual information in a structured manner, providing explicit, interpretable knowledge that includes domain-specific information from the cybersecurity scientific literature. One of the challenges in constructing a KG from scientific literature is the extraction of ontology from unstructured text. In this paper, we address this topic and introduce a method for building a multi-modal KG by extracting structured ontology from scientific papers. We demonstrate this concept in the cybersecurity domain. One modality of the KG represents observable information from the papers, such as the categories in which they were published or the authors. The second modality uncovers latent (hidden) patterns of text extracted through hierarchical and semantic non-negative matrix factorization (NMF), such as named entities, topics or clusters, and keywords. We illustrate this concept by consolidating more than two million scientific papers uploaded to arXiv into the cyber-domain, using hierarchical and semantic NMF, and by building a cyber-domain-specific KG. Copyright © 2024, The Authors. All rights reserved.

关键词： Knowledge graph

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Non-equilibrium thermodynamics of charge separation in organic solar cells

arXiv

引用

arXiv 2019年

作者： Kaiser, W. Janković, V. Vukmirović, N. Gagliardi, A. Department of Electrical and Computer Engineering Technical University of Munich KarlstraÃ e 45 Munich80333 Germany Scientific Computing Laboratory Center for the Study of Complex Systems Institute of Physics Belgrade University of Belgrade Pregrevica 118 Belgrade11080 Serbia

This work presents a novel theoretical description of the non-equilibrium thermodynamics of charge separation process in organic solar cells (OSCs). Using the theory of stochastic thermodynamics, we connect the phonon-assisted dynamics and recombination of electron-hole pairs within a photo-excited organic bilayer with the thermodynamic free energy. We analyze the impact of energetic disorder and delocalization on the free energy, average energy and entropy. For high energetic disorder, the site population is well described by equilibrium. We observe significant deviations from equilibrium for delocalized electron-hole pairs at small energetic disorder, representing efficient OSCs. Our results emphasize that both a large Gibbs entropy and large initial separation are required to achieve efficient charge separation. A decrease in free energy barrier with increased distances between charges does not necessarily correlate with the separation yield. Our presented framework can further shed light on the transient thermodynamic free energy, allowing previously inaccessible insight into the individual thermodynamic contributions from energy and entropy on sub-ns timescales. Transient simulations reveal large Gibbs entropy on ps-timescales for even highest disorder, which may explain the efficient separation of "hot" CT states. Copyright © 2019, The Authors. All rights reserved.

关键词： Organic solar cells

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Authenticated key distribution and secure broadcast using no conventional encryption: a unified approach based on block codes

Authenticated key distribution and secure broadcast using no...

引用

IEEE Conference and Exhibition on Global Telecommunications (GLOBECOM)

作者： R.H. Deng Li Gong A.A. Lazar Weiguo Wang Institute of Systems Science National University of Singapore Singapore Computer Science Laboratory SRI International Inc. Menlo Park CA USA Department of Electrical Engineering and Center for Telecommunications Research Columbia University New York NY USA

To eliminate the use of conventional encryption and to improve protocol efficiency, one-way hash function based authenticated key distribution protocols have appeared in the literature following two distinct approaches: the first approach employs one-way hash function and bit-wise XOR operation; while the second approach makes use of one-way hash function and polynomial interpolation. In this paper, we present a new technique for constructing one-way hash function based protocols for authenticated key distribution. The technique makes use of systematic linear block codes in error-control coding theory, results in more efficient protocols compared with their counterparts in the literature, and in effect, unifies the above two approaches in designing such protocols. As a by product, a secure broadcast protocol is also given which is capable of distributing a data message of any size in one broadcast protocol message.

关键词： Broadcasting Protocols Block codes Polynomials Public key cryptography Authentication computer science Laboratories Data security System performance

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A Polarizer for the magnetic component of light

A Polarizer for the magnetic component of light

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Conference on Lasers and Electro-Optics/Pacific Rim, CLEOPR 2011

作者： Kihm, H.W. Kim, Q.H. Kihm, J.E. Bak, W.S. Eah, S.H. Kim, Dai-Sik Koo, S.M. Park, N.K. Nordlander, P. Lienau, C. Kim, H. Halas, N.J. Center for Subwavelength Optics Department of Physics and Astronomy Seoul National University Seoul 151-747 Korea Republic of Photonic Systems Laboratory School of EECS Seoul National University Seoul 151-744 Korea Republic of Department of Physics and Astronomy Rice University Houston Texas 77005 United States Institut für Physik Carl von Ossietzky Universität 26111 Oldenburg Germany Department of Electronics and Information Engineering Korea University Yeongi-gun Chungnam 339-700 Korea Republic of Department of Electrical and Computer Engineering Rice University Houston Texas 77005-1892 United States

ISBN: (纸本)9780977565771

Nature of light as an electromagnetic wave with transverse components has been confirmed using optical polarizers, which are sensitive to the electric field orientation only. Recent advances in optical technologies in nanometer scale demand their magnetic counterpart: optical magnetic polarizers. Here we experimentally establish the optical magnetic field polarization as a separate entity from the electric field polarization by showing that subwavelength circular metallic apertures predominantly sense the magnetic field component of light. © 2011 AOS.

关键词： Electromagnetic waves

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Binary Bleed: Fast Distributed and parallel Method for Automatic Model Selection

arXiv

引用

arXiv 2024年

作者： Barron, Ryan Eren, Maksim E. Bhattarai, Manish Boureima, Ismael Matuszek, Cynthia Alexandrov, Boian S. Theoretical Division Los Alamos National Laboratory Los Alamos United States Advanced Research in Cyber Systems Los Alamos National Laboratory Los Alamos United States Department of Computer Science and Electrical Engineering University of Maryland Baltimore CountyMD United States

In several Machine Learning (ML) clustering and dimensionality reduction approaches, such as non-negative matrix factorization (NMF), RESCAL, and K-Means clustering, users must select a hyper-parameter k to define the number of clusters or components that yield an ideal separation of samples or clean clusters. This selection, while difficult, is crucial to avoid overfitting or underfitting the data. Several ML applications use scoring methods (e.g., Silhouette and Davies Boulding scores) to evaluate the cluster pattern stability for a specific k. The score is calculated for different trials over a range of k, and the ideal k is heuristically selected as the value before the model starts overfitting, indicated by a drop or increase in the score resembling an elbow curve plot. While the grid-search method can be used to accurately find a good k value, visiting a range of k can become time-consuming and computationally resource-intensive. In this paper, we introduce the Binary Bleed method based on binary search, which significantly reduces the k search space for these grid-search ML algorithms by truncating the target k values from the search space using a heuristic with thresholding over the scores. Binary Bleed is designed to work with single-node serial, single-node multi-processing, and distributed computing resources. In our experiments, we demonstrate the reduced search space gain over a naive sequential search of the ideal k and the accuracy of the Binary Bleed in identifying the correct k for NMFk, K-Means pyDNMFk, and pyDRESCALk with Silhouette and Davies Boulding scores. We make our implementation of Binary Bleed for the NMF algorithm available on GitHub. Copyright © 2024, The Authors. All rights reserved.

关键词： Non-negative matrix factorization

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Traffic-Aware Two-Stage Queueing Communication Networks: Queue Analysis and Energy Saving

Traffic-Aware Two-Stage Queueing Communication Networks: Que...

引用

作者： Qi, Nan Miridakis, Nikolaos I. Xiao, Ming Tsiftsis, Theodoros A. Yao, Rugui Jin, Shi Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information Technology Nanjing University of Aeronautics and Astronautics Nanjing210016 China National Mobile Communications Research Laboratory Southeast University Nanjing210096 China Institute of Physical Internet School of Intelligent Systems Science & Engineering Jinan University Zhuhai Campus Zhuhai519070 China Department of Informatics and Computer Engineering University of West Attica Aegaleo12243 Greece School of Electrical Engineering of KTH Royal Institute of Technology Stockholm11428 Sweden School of Electronics and Information Northwestern Polytechnical University Xi'an710072 China National Mobile Communications Research Laboratory Southeast University Nanjing210096 China

To boost energy saving for the general delay-tolerant IoT networks, a two-stage, and single-relay queueing communication scheme is investigated. Concretely, a traffic-aware $N$-threshold and gated-service policy are applied at the relay. As two fundamental and significant performance metrics, the mean waiting time and long-term expected power consumption are explicitly derived and related with the queueing and service parameters, such as packet arrival rate, service threshold and channel statistics. Besides, we take into account the electrical circuit energy consumptions when the relay server and access point (AP) are in different modes and energy costs for mode transitions, whereby the power consumption model is more practical. The expected power minimization problem under the mean waiting time constraint is formulated. Tight closed-form bounds are adopted to obtain tractable analytical formulae with less computational complexity. The optimal energy-saving service threshold that can flexibly adjust to packet arrival rate is determined. In addition, numerical results reveal that: 1) sacrificing the mean waiting time not necessarily facilitates power savings;2) a higher arrival rate leads to a greater optimal service threshold;and 3) our policy performs better than the current state-of-the-art. © 2020 IEEE.

关键词： Energy conservation

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