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Stability analysis of gradient-based distributed formation control with heterogeneous sensing mechanism: Two and three robot case

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arXiv 2020年

作者： Chan, Nelson P.K. Jayawardhana, Bayu de Marina, Hector Garcia Engineering and Technology Institute Groningen University of Groningen Nijenborgh 4 Groningen9747AG Netherlands Department of Computer Architecture and Automatic Control at the Faculty of Physics Universidad Complutense de Madrid Madrid28040 Spain

This paper focuses on the stability analysis of a formation shape displayed by a team of mobile robots that uses heterogeneous sensing mechanism. Depending on the convenience and reliability of the local information, each robot utilizes the popular gradient-based control law which, in this paper, is either the distance-based or the bearing-only formation control. For the two and three robot case, we show that the use of heterogeneous gradient-based control laws can give rise to an undesired invariant set where a distorted formation shape is moving at a constant velocity. The (in)stability of such an invariant set is dependent on the specified distance and bearing constraints. For the two robot case, we prove almost global stability of the desired equilibrium set while for the three robot case, we guarantee local asymptotic stability for the correct formation shape. We also derive conditions for the three robot case in which the undesired invariant set is locally attractive. Numerical simulations are presented for illustrating the theoretical results in the three robot *** Codes 34H05, 70E60, 93C10, 93C85 © 2020, CC-BY-NC-SA.

关键词： Control theory

Angle-Constrained Formation Control for Circular Mobile Robots

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arXiv 2020年

— In this letter, we investigate the formation control problem of mobile robots moving in the plane where, instead of assuming robots to be simple points, each robot is assumed to have the form of a disk with equal radius. Based on interior angle measurements of the neighboring robots’ disk, which can be obtained from low-cost vision sensors, we propose a gradient-based distributed control law and show the exponential convergence property of the associated error system. By construction, the proposed control law has the appealing property of ensuring collision avoidance between neighboring robots. We also present simulation results for a team of four circular mobile robots forming a rectangular *** Codes 34H05, 70E60, 93C10, 93C85 Copyright © 2020, The Authors. All rights reserved.

关键词： Mobile robots

Soft Error Mitigation for Deep Convolution Neural Network on FPGA Accelerators

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Soft Error Mitigation for Deep Convolution Neural Network on...

IEEE International Conference on Artificial Intelligence Circuits and Systems (AICAS)

作者： Wenshuo Li Guangjun Ge Kaiyuan Guo Xiaoming Chen Qi Wei Zhen Gao Yu Wang Huazhong Yang Department of Electronic Engineering BNRist Tsinghua University Beijing China State Key Laboratory of Computer Architecture Institute of Computing Technology CAS Beijing China Tianjin International Engineering Institute Tianjin University Tianjin China

ISBN: (数字)9781728149226

ISBN: (纸本)9781728149233

Convolution neural networks (CNNs) have been widely used in many applications. Field-Programmable Gate Array (FPGA) based accelerator is an ideal solution for CNNs in embedded systems. However, the single event upset (SEU) effect in FPGA device may have a significant influence on the performance of CNNs. In this paper, we analyze the sensibility of CNNs to SEU and present a fault-tolerant design for CNN accelerators. First, we find that SEU in processing elements (PEs) has the worst effects on CNNs since it produces proportional errors and will not get refreshed. Furthermore, it is indicated that the large positive perturbation contributes almost all of the performance loss. Based on such observations, we propose an error detecting scheme to locate incorrect PEs and give an error masking method to achieve fault-tolerance. Experiments demonstrate that the proposed method achieves similar fault-tolerant performance with the triple modular redundancy (TMR) scheme while the overhead is much lower than it.

关键词： Table lookup Adders Field programmable gate arrays Single event upsets Neural networks Fault tolerance

Impact of NBTI on Increasing the Susceptibility of FinFET to Radiation

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Impact of NBTI on Increasing the Susceptibility of FinFET to...

Annual International Symposium on Reliability Physics

作者： Frank Sill Torres Hussam Amrouch Jörg Henke Rolf Drechsler Group of Computer Architecture University of Bremen Germany Department of Computer Science Karlsruhe Institute of Technology (KIT) Karlsruhe Germany

This work investigates the interaction between Neg-ative Bias Temperature Instability (NBTI)and radiation effects in 14nm FinFET devices. Due to the complex interaction between traps generated by NBTI and induced charges by strikes of ionizing particles, we opted for a complete physical-based analysis using TCAD mixed-mode simulations. This enables an accurate estimation and then modeling of the duration a circuit requires to recover from a particle strike and, thus, return to correct operation under the effects of NBTI. This a crucial aspect, because the longer the recovery time, the higher the probabilities of a soft-error and that this error remains undetected. Further, our employed setup enables an accurate determination of the critical charge (Q crit ), i. e. the minimum collected charge that results into a faulty transition of a circuit's output node. Our investigation reveals that there is indeed a strong relation between NBTI and the time a circuit remains in faulty state. Consequently, detection schemes must be adapted during circuit's operation to take aging into account in order to avoid that errors remain undetected.

关键词： Negative bias temperature instability Thermal variables control Inverters Ions Circuit faults FinFETs Load modeling

Relationship among state reopening policies, health outcomes and economic recovery through first wave of the COVID-19 pandemic in the U.S

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arXiv 2021年

作者： Ligo, Alexandre K. Mahoney, Emerson Cegan, Jeffrey Trump, Benjamin D. Jin, Andrew S. Kitsak, Maksim Keenan, Jesse Linkov, Igor US Army Corps of Engineers Engineer Research and Development Center ConcordMA United States University of Virginia Department of Engineering Systems and Environment CharlottesvilleVA United States Delft University of Technology Faculty of Electrical Engineering Mathematics and Computer Science Delft Netherlands Carnegie Mellon University Department of Engineering and Public Policy PittsburghPA United States Tulane University School of Architecture New OrleansLA United States

State governments in the U.S. have been facing difficult decisions involving tradeoffs between economic and health-related outcomes during the COVID-19 pandemic. Despite evidence of the effectiveness of government-mandated restrictions mitigating the spread of contagion, these orders are stigmatized due to undesirable economic consequences. This tradeoff resulted in state governments employing mandates at widely different ways. We compare the different policies states implemented during periods of restriction ("lockdown") and reopening with indicators of COVID-19 spread and consumer card spending at each state during the first "wave" of the pandemic in the U.S. between March and August 2020. We find that while some states enacted reopening decisions when the incidence rate of COVID-19 was minimal or sustained in its relative decline, other states relaxed socioeconomic restrictions near their highest incidence and prevalence rates experienced so far. Nevertheless, all states experienced similar trends in consumer card spending recovery, which was strongly correlated with reopening policies following the lockdowns and relatively independent from COVID-19 incidence rates at the time. Our findings suggest that consumer card spending patterns can be attributed to government mandates rather than COVID-19 incidence in the states. We estimate the recovery in states that reopened in late April was more than the recovery in states that did not reopen in the same period – 15% for consumer card spending and 18% for spending by high income households. This result highlights the important role of state policies in minimizing health impacts while promoting economic recovery and helps planning effective interventions in subsequent waves and immunization efforts. © 2021, CC BY.

关键词： SARS

ecUWB: A Energy-Centric Communication Scheme for Unstable WiFi Based Backscatter Systems : (Invited Paper)

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ecUWB: A Energy-Centric Communication Scheme for Unstable Wi...

International Conference on computer Communications and Networks (ICCCN)

作者： Yue Xu Jingwen Zhang Hao Zhou Xiaoyan Wang Zhi Liu Yusheng Ji LINKE Lab School of Computer Science and Technology Univ. of Science and Technology of China China College of Engineering Ibaraki University Japan Department of Mathematical and Systems Engineering Shizuoka University Japan Information Systems Architecture Research Division National Institute of Informatics Japan

ISBN: (数字)9781728166070

ISBN: (纸本)9781728166087

By integrating both energy harvesting and backscatter communication technologies, so-called `battery-free tag' emerges as a promising solution to the energy related issues in IoT. However, such tags present new challenges due to the unstable energy supply and excitation signals, which are critical to realize successful backscatter communications. In this paper, we present a novel system, denoted as ecUWB, which enables robust communication for battery-free tags where unstable WiFi signals act as the unified source for both energy supply and excitation signals. At tag side, we propose a charging-transmission division scheme to achieve better signal utilization, and introduce a re-transmission mechanism for possible excitation signal interruption. At receiver side, we implement a simply method which is based on DBSCAN (Density-Based Spatial Clustering of Applications with Noise) to predict the uncontrollable signals, and propose an energy-centric tag scheduling method according to the tag energy estimation results. Extensive experiments are carried out on customized tags and NI USRP platform. The results show that ecUWB outperforms the existing ones in terms of performance and efficiency under the unstable WiFi signals.

关键词： Wireless fidelity Backscatter Energy harvesting Receivers Systems architecture Power supplies Modulation

Neural relation extraction: a survey

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arXiv 2020年

作者： Aydar, Mehmet Bozal, Ozge Ozbay, Furkan AI Enablement Department Huawei Turkey Research and Development Center Istanbul Turkey Enterprise Architecture and Technology Innovation Ford Otosan Istanbul Turkey Department of Computational Science and Engineering Bogazici University Istanbul Turkey Department of Computer Engineering Yildiz Technical University Istanbul Turkey

Neural relation extraction discovers semantic relations between entities from unstructured text using deep learning methods. In this study, we present a comprehensive review of methods on neural network based relation extraction. We discuss advantageous and incompetent sides of existing studies and investigate additional research directions and improvement ideas in this field. Copyright © 2020, The Authors. All rights reserved.

关键词： Extraction

Acceleration and energy consumption optimization in cascading classifiers for face detection on low-cost ARM big. LITTLE asymmetric architectures

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Acceleration and energy consumption optimization in cascadin...

作者： Corpas, Alberto Costero, Luis Botella, Guillermo Igual, Francisco D. García, Carlos Rodríguez, Manuel Department of Architecture and Computer Technology ETSIIT University of Granada Granada18071 Spain Department of Computer Architecture and Automation Complutense University of Madrid Madrid28040 Spain

This paper proposes a mechanism to accelerate and optimize the energy consumption of a face detection software based on Haar-like cascading classifiers, taking advantage of the features of low-cost asymmetric multicore processors (AMPs) with limited power budget. A modelling and task scheduling/allocation is proposed in order to efficiently make use of the existing features on big. LITTLE ARM processors, including (1) source-code adaptation for parallel computing, which enables code acceleration by applying the OmpSs programming model, a task-based programming model that handles data-dependencies between tasks in a transparent fashion;(2) different OmpSs task allocation policies which take into account the processor asymmetry and can dynamically set processing resources in a more efficient way based on their particular features. The proposed mechanism can be efficiently applied to take advantage of the processing elements existing on low-cost and low-energy multi-core embedded devices executing object detection algorithms based on cascading classifiers. Although these classifiers yield the best results for detection algorithms in the field of computer vision, their high computational requirements prevent them from being used on these devices under real-time requirements. Finally, we compare the energy efficiency of a heterogeneous architecture based on AMPs with a suitable task scheduling with that of a homogeneous symmetric architecture. © 2018 John Wiley & Sons, Ltd.

关键词： Energy efficiency

Computational prediction of the stability of tensegrity structures 7

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Computational prediction of the stability of tensegrity stru...

7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, COMPDYN 2019

作者： Bieniek, Z. Mascolo, I. Amendola, A. Micheletti, A. Luciano, R. Fraternali, F. Faculty of Civil and Environmental Engineering and Architecture Rzeszów University of Technology Rzeszów Poland Department of Civil Engineering University of Salerno Italy Department of Civil Engineering and Computer Science University of Rome Tor Vergata Italy Department of Engineering University of Naples "Parthenope" Naples Italy

ISBN: (纸本)9786188284470

The lightweight nature of tensegrity structures calls for the formulation of computational tools that are able to analyze the stability problem of such structures, both in statics and dynamics. The present work analyzes the concepts of prestress-stability and superstability with reference to a special class of tensegrity structures recently appeared in the literature, named class theta tensegrity prisms. Such structures are formed by two triangular prisms superimposed one over the other, and two different sets of strings connecting the two prisms. The given results can be easily generalized to general tensegrity structures and can be usefully incorporated in form-finding and topology optimization codes. © 2019 The authors.

关键词： Stability