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17th IFAC workshop on Time Delay Systems (TDS)

作者： Faghihi, Mohammad Amin Tashakori, Shabnam Yazdi, Ehsan Azadi Eghtesad, Mohammad van de Wouw, Nathan Shiraz Univ Dept Mech Engn Shiraz Iran Univ Aberdeen Ctr Appl Dynam Res Sch Engn Aberdeen Scotland Shiraz Univ Technol Dept Mech & Aerosp Engn Shiraz Iran Rahesh Innovat Ctr Tehran Iran Eindhoven Univ Technol Dept Mech Engn NL-5600 MB Eindhoven Netherlands

this article proposes an active control strategy to suppress self-excited coupled axial-torsional vibrations of a distributed drill-string system while the coupling takes place through the bit-rock interaction. the drill-string model is expressed as Neutral-type Delay Differential Equations (NDDEs) with constant and state-dependent state delays and constant input delays. As a first step in the novel controller design, an implementable input transformation is introduced, resulting in the elimination of the neutral terms from the equations of motion. this supports a simplified next step of stabilizing controller design. In the second step, a new analytic method named the "Eigenvector Contradiction Method" is proposed to provide sufficient conditions to ensure that all eigenvalues have real parts less than a prescribed value. Based on this criterion, an automated parametric feedback control law is designed. A case study simulation is presented to illustrate the effectiveness of the proposed control *** (c) 2022 the Authors. this is an open access article under the CC BY-NC-ND license (https://***/licenses/by-nc-nd/4.0/)

关键词： distributed drill-string Coupled axial-torsional vibrations Neutral-type Time-Delay (NTD) model State-dependent delay Input delay

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Design of a Reflectarray Fed by a Planar Leaky-Wave Antenna for 3U CubeSats

Design of a Reflectarray Fed by a Planar Leaky-Wave Antenna ...

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UK, Europe, China Millimeter Waves and thz Technology workshop (UCMMT)

作者： Daniel R. Prado Miguel Poveda-García George Goussetis Lei Wang School of Engineering Lancaster University U.K. Department of Information and Communications Technologies Technical University of Cartagena Spain Institute of Sensors Signals and Systems Heriot-Watt University Edinburgh U.K.

ISBN: (数字)9798331530228

ISBN: (纸本)9798331530235

this work presents the design of a reflectarray fed by a planar leaky-wave antenna (LWA) for use in a 3U CubeSat. the LWA is based on substrate-integrated waveguide (SIW) technology and radiates in single-linear polarization. A full-wave simulation is carried out to obtain the near field radiated by the SIW LWA on a surface corresponding to the reflectarray, whose size is set to fit three sides of the CubeSat for stowage and deployment. A single-layered reflectarray unit cell consisting of three parallel dipoles has been chosen for simplicity and low profile. It provides a phase-shift range of more than 360° for layout design. In addition, the angle of incidence of the impinging near field is calculated by means of the Poynting vector. simulation results at 24 GHz show the suitability of the design procedure for point-to-point communications, achieving an estimated gain of more than 30 dBi, taking into account substrate losses, and illumination and spillover efficiencies.

关键词： Surface waves simulation Lighting Terahertz materials Leaky wave antennas Reflector antennas Vectors Surface fitting CubeSat Substrates

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Latin Square Job Scheduling for distributed Data Processing on Warehouse-Scale Computers

Latin Square Job Scheduling for Distributed Data Processing ...

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IEEE International Conference on Utility and Cloud Computing (UCC)

作者： Kevin Exton Maria A. Rodriguez School of Computing and Information Systems The University of Melbourne Melbourne Australia

ISBN: (数字)9798350367201

ISBN: (纸本)9798350367218

Large-scale parallelizable data processing jobs, executed by frameworks like Spark, frequently have heavily skewed response time distributions with long tail times. this phenomenon is known as straggling and it occurs when one or more of the parallel tasks belonging to a job takes much longer than normal to complete. As a single root cause for straggling in large-scale systems is difficult to identify, we consider it to be a symptom of temporary node impairment caused by random bursts of interference. Since latin squares are commonly used in many applications that need to mitigate external sources of variation or interference, we examine how they might benefit modern distributed data processing workloads. Based on the latin square combinatorial block design, we develop a scheduling policy that we call the latin square scheduling policy. Using a combination of simulation and theoretical analysis, we argue that our policy can outperform other common schemes such as random, round-robin, Sparrow, and Peacock, when there is a sufficient quantity of time-dependent intermittent burst interference.

关键词： Computers Cloud computing Processor scheduling Interference Tail Data processing Large-scale systems Time factors Sparks

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Robustification of Proportional-Resonant Control Against Frequency Variations

Robustification of Proportional-Resonant Control Against Fre...

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International workshop on Variable Structure Systems, VSS

作者： Juan G. Rueda-Escobedo Jaime A. Moreno Guillermo Ocaña Anaya División de Ciencias Básicas Facultad de Ingeniería Universidad Nacional Autónoma de México (UNAM) CDMX Mexico Eléctrica y Computación Instituto de Ingeniería Universidad Nacional Autónoma de México (UNAM) CDMX Mexico

ISBN: (数字)9798350353686

ISBN: (纸本)9798350353693

Replacing traditional power generation with distributed sources leads to a grid frequency that is more vulnerable to fluctuations. this can impact the efficiency and function of power converters, which are essential for integrating renewable energies into the electrical network. Instead of estimating and tracking the grid’s frequency to counter these changes, this paper proposes a robust proportional-resonant (PR) controller that maintains reference tracking in the presence of a varying frequency. Unlike other approaches, the proposed controller does not require precise knowledge of the frequency. this is made possible by integrating into the PR controller a second-order bi-homogeneous differentiator, significantly improving the controller’s tracking performance. the performance of the proposed approach is demonstrated through numerical simulations involving the operation of a grid-connected inverter during a frequency variation event.

关键词： Variable structure systems Time-frequency analysis Renewable energy sources Filters Harmonic analysis Numerical simulation Frequency estimation Frequency control Power harmonic filters Power generation

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17th IEEE International workshop on Automatic Performance Tuning (iWAPT2022)

17th IEEE International Workshop on Automatic Performance Tu...

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IEEE International Symposium on parallel and distributed Processing workshops and Phd Forum (IPDPSW)

作者： Che-Rung Lee Satoshi Ohshima

ISBN: (数字)9781665497473

ISBN: (纸本)9781665497480

the goal of the Seventeenth International workshop on Automatic Performance Tuning (iWAPT2022) is to bring together researchers who are investigating automated techniques for constructing and/or adapting algorithms and software for high-performance on modern complex machine architectures. iWAPT is a series of workshops that focus on research and techniques related to performance sustainability issues. the series provides an opportunity for researchers and users of automatic performance tuning (AT) technologies to exchange ideas and experiences acquired when applying such technologies to improve the performance of algorithms, libraries, and applications; in particular, on cutting edge computing platforms. the half-day workshops consist of presentations of research papers. Topics of interest include performance modeling; adaptive algorithms; autotuned numerical algorithms; libraries and scientific applications; empirical compilation; automated code generation; frameworks and theories of AT and software optimization; autonomic computing; and context-aware computing.

关键词： Conferences Tuning Software algorithms Software Libraries Sustainable development Scientific computing

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Machine Learning-Based, Networking and Computing Infrastructure Resource Management 17th

Machine Learning-Based, Networking and Computing Infrastruct...

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17th IFIP WG 12.5 International Conference on Artificial Intelligence Applications and Innovations (AIAI) / 6th 5G-PINE workshop / AI-BIO workshop / DAAI workshop / DARE workshop / EEAI workshop / 10th MHDW workshop

作者： Chochliouros, Ioannis P. Kostopoulos, Alexandros Payaro, Miquel Verikoukis, Christos di Vimercati, Sabrina De Capitani Vinogradov, Evgenii Ranjbar, Vida Vardakas, John Rahman, Md Arifur Soumplis, Polyzois Varvarigos, Emmanuel Hellen Telecommun Org OTE SA 99 Kifissias Ave Athens 15124 Greece Ctr Tecnol Telecomunicac Catalunya CTTC CERCA Barcelona Spain Univ Milan Milan Italy Katholieke Univ Leuven Leuven Belgium Iquadrat Informat SL Barcelona Spain IS Wireless Warsaw Poland Inst Commun & Comp Syst ICCS Athens Greece

ISBN: (纸本)9783030791599;9783030791575;9783030791568

5G mobile networks will be soon available to handle all types of applications and to provide service to massive numbers of users. In this complex and dynamic network ecosystem, end-to-end performance analysis and optimization will be key features in order to effectively manage the diverse requirements imposed by multiple vertical industries over the same shared infrastructure. To enable such a vision, the MARSAL project [ 1] targets the development and evaluation of a complete framework for the management and orchestration of network resources in 5G and beyond by utilizing a converged optical-wireless network infrastructure in the access and fronthaul/midhaul segments. At the network design domain, MARSAL targets the development of novel cell-free-based solutions. Namely, scalable and cost-efficient wireless access points deployment will be achieved by exploiting the distributed cell-free concept combined with wireless and wired serial fronthaul approaches. We will target the inclusion of these innovative functionalities in the O-RAN project. In parallel, in the fronthaul/midhaul segments MARSAL aims to radically increase the flexibility of optical access architectures for Beyond-5G cell site connectivity via different levels of fixed-mobile convergence. In the network and service management domain, the design philosophy of MARSAL is to provide a comprehensive framework for the management of the entire set of communication and computational network resources by exploiting novel ML-based algorithms of both edge and midhaul data centers, by incorporating the Virtual Elastic Data Centers/Infrastructures paradigm. Finally, at the network security domain, MARSAL aims to introduce mechanisms that provide privacy and security to application workload and data, targeting to allow applications and users to maintain control over their data when relying on the deployed shared infrastructures, while AI and Blockchain technologies will be developed in order to guarantee a secured

关键词： Cell-free distributed cloud Network automation Machine learning Secure multi-tenancy

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Ultra-wide Power Range High-Efficiency RF Rectifier

Ultra-wide Power Range High-Efficiency RF Rectifier

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UK, Europe, China Millimeter Waves and thz Technology workshop (UCMMT)

作者： Jincai Qiao Bo Zhang Kai Kang Gang Yang Qingfeng Zhang Yiming Yu Jin Li Zhongqian Niu Yinian Feng Yong Fan Xiaobo Yang Chongqing Institute of Microelectronics Industry Technology University of Electronic Science and Technology of China Chongqing China The Shenzhen Institute for Advanced Study University of Electronic Science and Technology of China Shenzhen China School of Electronic Science and Engineering University of Electronic Science and Technology of China Chengdu China

ISBN: (数字)9798331530228

ISBN: (纸本)9798331530235

In this thesis, a dual-branch dual-load parallel rectifier circuit structure is adopted. By adding a T-type unequal division structure for automatic power distribution, a band-stop structure is added at the end of the diode to expand the dynamic range of impedance matching, achieving wide dynamic input power matching and improving conversion efficiency. the open-circuited microstrip line TL11 and the π-type microstrip structure at the front end of the diode dynamically change the input voltage through passive voltage adjustment, which can reduce diode loss and eliminate the overlap of voltage and current harmonics, thereby reducing the diode's turn-on loss. By changing the voltage at both ends of the diode, the rectification efficiency can be improved, and the optimal working power point of the diode can be adjusted. then, according to the needs, the two rectifier branches work efficiently under different input powers, thus achieving high conversion efficiency of the circuit over a wide input power dynamic range. simulation results show that the rectification efficiency of the rectifier circuit reaches a maximum of 76.9% at a frequency of 5.8 GHz and an impedance of 650 Ω with an input power of 15 dBm, and the rectification efficiency is greater than 50% in the input power range of -0.1 dBm to 36.4 dBm, achieving high-efficiency rectification over an ultra-wide input power dynamic range.

关键词： Radio frequency Impedance matching simulation Rectifiers Power distribution Voltage Terahertz materials Dynamic range Microstrip Impedance

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3D CFD Coolant System simulation for Vehicle Drive-Cycle 17

3D CFD Coolant System Simulation for Vehicle Drive-Cycle

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SAE 2021 17th Symposium on International Automotive Technology, SIAT 2021

作者： Varshney, Mehul Ballani, Abhishek Pasunurthi, Shyam Sundar Maiti, Dipak Srinivasan, Chiranth Simerics India India Simerics Inc

the present work deals with the 3-D, transient, system level CFD simulation of an automotive coolant system using a 3D CFD solver Simerics MP+®. the system includes actual CAD of radiator, cooling jacket, coolant pump, bypass valve and thermostat valve. this work is in continuation of the work done by Srinivasan et al. [1] where wax melting, conjugate heat transfer, Fluid Structure Interaction (FSI) of the valve had been solved. thermostat valve was controlled by wax phase change model which also incorporates the hysteresis effect of wax melting and solidification. the previous work dealt with the simulation of complete cycle, opening, and closing of the thermostat valve system. Besides the physics considered in the previous study, the current model also includes the treatment of cavitation to account for the presence of dissolved gases and vaporization of the liquid coolant. A methodology has been developed and implemented where the run-time of such a system has been made considerably faster to be able to simulate complete drive cycle tests. the distributed parallel solver of Simerics-MP+, coupled with the newly developed method made it to successfully simulate an HOUR of drive-cycle of coolant system within a day of simulation time. Various parameters from experimental measurements have been corroborated with the simulation results to validate the developed technology. Further, a few design iterations are performed to showcase the potential of the developed methodology. © 2021 SAE International. All Rights Reserved.

关键词： Fluid structure interaction

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Aggregate centrality measures for IoT-based coordination

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SCIENCE OF COMPUTER PROGRAMMING 2021年 203卷 102584-102584页

作者： Audrito, Giorgio Pianini, Danilo Damiani, Ferruccio Viroli, Mirko Univ Torino Turin Italy Univ Bologna Alma Mater Studiorum Cesena Italy

Collecting statistics from graph-based data is an increasingly studied topic in the data mining community. We argue that they can have great value in the coordination of dynamic IoT systems as well, especially to support complex coordination strategies related to distributed situation recognition. thanks to a mapping to the field calculus, a distribution coordination model proposed for collective adaptive systems, we show that many existing "centrality measures" for graphs can be naturally turned into field computations that compute the centrality of nodes in a network. Not only this mapping gives evidence that the field coordination is well-suited to accommodate massively parallel computations over graphs, but also it provides a new basic "brick" of coordination which can be used in several contexts, there including improved leader election or network vulnerabilities detection. We validate our findings by simulation, first measuring the ability of the translated algorithm to self-adjust to network changes, then investigating an application of centrality measures for data summarisation. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Graph algorithms Network centrality distributed computing Aggregate computing

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A Novel Decentralized Virtual Impedance Droop Integrating Phase Locked Loop (PLL) Control Scheme for parallel DG Inverter in an Islanded Microgrid 17

A Novel Decentralized Virtual Impedance Droop Integrating Ph...

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17th IEEE India Council International Conference, INDICON 2020

作者： Behera, Manoja Kumar Raj, Ravi Saikia, Lalit Chandra National Institute of Technology Silchar Department of Electrical Engineering Silchar Assam788010 India

ISBN: (纸本)9781728169163

the integration of distributed generation (DG) units and their control is one of the major challenges in the islanded microgrid environment. this paper introduced a novel decentralized control strategy for parallel operation of DG inverter in an islanded microgrid. the controller presented here wipes out the requirement of a wire based communication line. the controller assimilates virtual impedance drooping with the phase locked loop (PLL). the synchronous reference frame (SRF) provides active and reactive power based on frequency and voltage reference. the proposed controller requires basic loop like power control, voltage and current control. Mainly, the resistive nature of the line has poor performance with conventional droop that results in improper synchronization of the controller. simulation is performed on MATLAB simulink platform and results are compared with the conventional droop technique. the presented controller improves synchronization, decoupling of reactive (Q) and active power (P), and the response of the system. © 2020 IEEE.

关键词： Controllers

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