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Driver's Visual Luminance Model Considering the Reflection Characteristics of a Tunnel's Inner Wall: Theory and Practice Ii

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SSRN

SSRN 2023年

作者： He, Shiyong Liu, Hao Bhusal, Pramod Shi, Lingna Li, Jie Niu, Jia'an Cai, Xianyun Liang, Bo State Key Laboratory of Mountain Bridge and Tunnel Engineering Chongqing Jiaotong University Chongqing China Chongqing Expressway Group Co . Ltd. Chongqing401346 China Department of Electrical Engineering and Automation Lighting Unit School of Electrical Engineering Aalto University Espoo Finland Traffic Engineering and Energy-saving Department China Merchants Chongqing Communications Research & Design Institute Co. Ltd Chongqing400067 China College of Architecture and Urban Planning Chongqing Jiaotong University Chongqing China

In the first part of this study, we established a visual luminance model for a tunnel which considered the driver and verified the accuracy of the model based on a 1:10 scale simulation tunnel model. Although the established visual luminance model is based on a straight-wall side wall and cement concrete pavement, most of the design of the practical tunnel is based on the curved-wall side wall and asphalt concrete pavement. The core of this study concerns this distinction. For example, what is the accuracy of the model in the practical tunnel? Can it reflect the reflection characteristics of the material in an actual tunnel? Can it solve general practical engineering application? In view of these, in this study, we derive a formula for a three-dimensional coordinate transformation based on a tunnel's geometric section structure and apply it to the established visual luminance model to solve a calculation problem of the model for a curved-wall side wall. In addition, the model describing the bidirectional reflectance distribution function is optimised and a more accurate six-parameter model is used to express it, verifying the reliability of the optimisation model. We design a standard field test plan, collect data, and analyse the calculated model results based on the test data. The results show that the relative error rate between the theoretical results and measured data can be controlled within 5.7%, confirming the accuracy of the model. © 2023, The Authors. All rights reserved.

关键词： Energy conservation

Graph Attention-based Reinforcement Learning for Trajectory design and Resource Assignment in Multi-UAV Assisted Communication

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arXiv 2024年

作者： Feng, Zikai Wu, Di Huang, Mengxing Yuen, Chau School of Information and Communication Engineering Hainan University State Key Laboratory of Marine Resource Utilization in South China Sea Haikou570228 China The Engineering Product Development Pillar Singapore University of Technology and Design 487372 Singapore The Department of Automation Shanghai Jiao Tong University Shanghai200240 China PRISMA Lab University of Naples Federico II Naples80125 Italy The School of Electrical and Electronic Engineering Nanyang Technological University 639798 Singapore

In the multiple unmanned aerial vehicle (UAV)assisted downlink communication, it is challenging for UAV base stations (UAV BSs) to realize trajectory design and resource assignment in unknown environments. The cooperation and competition between UAV BSs in the communication network leads to a Markov game problem. Multi-agent reinforcement learning is a significant solution for the above decision-making. However, there are still many common issues, such as the instability of the system and low utilization of historical data, that limit its application. In this paper, a novel graph-attention multi-agent trust region (GA-MATR) reinforcement learning framework is proposed to solve the multi-UAV assisted communication problem. Graph recurrent network is introduced to process and analyze complex topology of the communication network, so as to extract useful information and patterns from observational information. The attention mechanism provides additional weighting for conveyed information, so that the critic network can accurately evaluate the value of behavior for UAV BSs. This provides more reliable feedback signals and helps the actor network update the strategy more effectively. Ablation simulations indicate that the proposed approach attains improved convergence over the baselines. UAV BSs learn the optimal communication strategies to achieve their maximum cumulative rewards. Additionally, multi-agent trust region method with monotonic convergence provides an estimated Nash equilibrium for the multi-UAV assisted communication Markov *** Codes 68M11 Copyright © 2024, The Authors. All rights reserved.

关键词： Reinforcement learning

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GUEST EDITORIAL

China Communications 2023年第2期 3-6页

作者： Yuan Wu Xu Chen Feng Lyu Xianfu Chen Xumin Huang Jie Gao Yueyue Dai Tony Q.S.Quek Yan Zhang the State Key Laboratory of Internet of Things for Smart City University of Macau the Department of Computer and Information Science University of Macau Sun Yat-sen University Sun Yat-sen University Institute of Advanced Networking and Computing Systems Sun Yat-sen University National and Local Joint Engineering Laboratory the School of Computer Science and Engineering Central South University the VTT Technical Research Centre of Finland the School of Automation Guangdong University of Technology the School of Information Technology Carleton University Huazhong University of Science and Technology Singapore University of Technology and Design(SUTD) the IEEE Communications Society Technical Committee on Green Communications and Computing(TCGCC)

With the growing maturity of the advanced edge-cloud collaboration and integrated sensing-communication-computing systems, edge intelligence has been envisioned as one of the enabling technologies for ubiquitous and l...

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Towards Communication-efficient Federated Learning via Sparse and Aligned Adaptive Optimization

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arXiv 2024年

作者： Deng, Xiumei Li, Jun Wei, Kang Shi, Long Xiong, Zeihui Ding, Ming Chen, Wen Jin, Shi Poor, H. Vincent School of Electronic and Optical Engineering Nanjing University of Science and Technology Nanjing210094 China The Department of Computing Hong Kong Polytechnic University 999077 Hong Kong The Pillar of Information Systems Technology and Design Singapore University of Technology and Design Singapore Data61 CSIRO SydneyNSW2015 Australia Department of Electronics Engineering Shanghai Jiao Tong University Shanghai200240 China The National Mobile Communications Research Laboratory Southeast University Nanjing210096 China Department of Electrical and Computer Engineering Princeton University NJ08544 United States

Adaptive moment estimation (Adam), as a Stochastic Gradient Descent (SGD) variant, has gained widespread popularity in federated learning (FL) due to its fast convergence. However, federated Adam (FedAdam) algorithms suffer from a threefold increase in uplink communication overhead compared to federated SGD (FedSGD) algorithms, which arises from the necessity to transmit both local model updates and first and second moment estimates from distributed devices to the centralized server for aggregation. Driven by this issue, we propose a novel sparse FedAdam algorithm called FedAdam-SSM, wherein distributed devices sparsify the updates of local model parameters and moment estimates and subsequently upload the sparse representations to the centralized server. To further reduce the communication overhead, the updates of local model parameters and moment estimates incorporate a shared sparse mask (SSM) into the sparsification process, eliminating the need for three separate sparse masks. Theoretically, we develop an upper bound on the divergence between the local model trained by FedAdam-SSM and the desired model trained by centralized Adam, which is related to sparsification error and imbalanced data distribution. By minimizing the divergence bound between the model trained by FedAdam-SSM and centralized Adam, we optimize the SSM to mitigate the learning performance degradation caused by sparsification error. Additionally, we provide convergence bounds for FedAdam-SSM in both convex and non-convex objective function settings, and investigate the impact of local epoch, learning rate and sparsification ratio on the convergence rate of FedAdam-SSM. Experimental results show that FedAdam-SSM outperforms baselines in terms of convergence rate (over 1.1× faster than the sparse FedAdam baselines) and test accuracy (over 14.5% ahead of the quantized FedAdam baselines). Copyright © 2024, The Authors. All rights reserved.

关键词： Stochastic systems

Coordinated Guiding Vector Field design for Ordering-Flexible Multi-Robot Surface Navigation

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arXiv 2024年

作者： Hu, Bin-Bin Zhang, Hai-Tao Yao, Weijia Sun, Zhiyong Cao, Ming The School of Artificial Intelligence and Automation The Engineering Research Center of Autonomous Intelligent Unmanned Systems The Key Laboratory of Image Processing and Intelligent Control The State Key Lab of Digital Manufacturing Equipment and Technology Huazhong University of Science and Technology Wuhan430074 China The School of Robotics Hunan University Hunan410082 China The Institute of Engineering and Technology University of Groningen Groningen9747 AG Netherlands Department of Electrical Engineering Eindhoven University of Technology Netherlands

We design a distributed coordinated guiding vector field (CGVF) for a group of robots to achieve ordering-flexible motion coordination while maneuvering on a desired two-dimensional (2D) surface. The CGVF is characterized by three terms, i.e., a convergence term to drive the robots to converge to the desired surface, a propagation term to provide a traversing direction for maneuvering on the desired surface, and a coordinated term to achieve the surface motion coordination with an arbitrary ordering of the robotic group. By setting the surface parameters as additional virtual coordinates, the proposed approach eliminates potential singularity of the CGVF and enables both the global convergence to the desired surface and the maneuvering on the surface from all possible initial conditions. The ordering-flexible surface motion coordination is realized by each robot to share with its neighbors only two virtual coordinates, i.e. that of a given target and that of its own, which reduces the communication and computation cost in multi-robot surface navigation. Finally, the effectiveness of the CGVF is substantiated by extensive numerical simulations. Copyright © 2024, The Authors. All rights reserved.

关键词： Navigation

A data-driven two-microphone method for in-situ sound absorption measurements

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arXiv 2025年

作者： Emmerich, Leon Aste, Patrik Brandão, Eric Nolan, Mélanie Cuenca, Jacques Svensson, U. Peter Maeder, Marcus Marburg, Steffen Zea, Elias Department of Engineering Physics and Computation TUM School of Engineering and Design Technical University of Munich Boltzmannstrasse 15 Garching85748 Germany The Marcus Wallenberg Laboratory for Sound and Vibration Research Department of Engineering Mechanics KTH Royal Institute of Technology Teknikringen 8 Stockholm10044 Sweden RS Santa Maria97050-140 Brazil Acoustic Technology Department of Electrical and Photonics Engineering Technical University of Denmark Kgs. LyngbyDK-2800 Denmark Siemens Industry Software NV Interleuvenlaan 68 Leuven3001 Belgium Department of Electronic Systems Norwegian University of Science and Technology Trondheim Norway

This work presents a data-driven approach to estimating the sound absorption coefficient of an infinite porous slab using a neural network and a two-microphone measurement on a finite porous sample. A 1D-convolutional network predicts the sound absorption coefficient from the complex-valued transfer function between the sound pressure measured at the two microphone positions. The network is trained and validated with numerical data generated by a boundary element model using the Delany-Bazley-Miki model, demonstrating accurate predictions for various numerical samples. The method is experimentally validated with baffled rectangular samples of a fibrous material, where sample size and source height are varied. The results show that the neural network offers the possibility to reliably predict the in-situ sound absorption of a porous material using the traditional two-microphone method as if the sample were infinite. The normal-incidence sound absorption coefficient obtained by the network compares well with that obtained theoretically and in an impedance tube. The proposed method has promising perspectives for estimating the sound absorption coefficient of acoustic materials after installation and in realistic operational conditions. © 2025, CC BY.

关键词： Acoustic impedance

Modeling, simulation and experiment of an origami robot with a coupled bar-hinge mechanism

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Modeling, simulation and experiment of an origami robot with...

Fully Actuated System Theory and Applications (CFASTA), Conference on

作者： Junpeng Mai Hanzhao Shao Shaojie Liu Yuanzhuo Zhang Liangming Chen Huijuan Feng School of System Design and Intelligent Manufacturing and Shenzhen Key Laboratory of Control Theory and Intelligent Systems Southern University of Science and Technology Shenzhen P. R. China Department of Electronic and Electrical Engineering Southern University of Science and Technology Shenzhen P. R. China Department of Mechnical and Energy Engineering Southern University of Science and Technology Shenzhen P. R. China

ISBN: (数字)9798350373691

ISBN: (纸本)9798350373707

This paper aims to analyze the motion behavior of an origami robot with a coupled bar-hinge mechanism. By disassembling the planar six-hinge mechanism into two planar four-hinge mechanisms with coupled motion, this paper derives the kinematics of the planar six-hinge mechanism based on the algebraic differential kinematics of the planar four-hinge motions. The rotational angle change and the moving step length of the origami robot are further calculated. Finally, the theoretical motion model is verified with the motion simulation data of the planar six-hinge mechanism origami robot in SolidWorks and the experimental data of the physical model. This verification proves the feasibility of the theoretical analysis, simulation model, and physical model.

关键词： Solid modeling Analytical models Prototypes Kinematics Three-dimensional printing Mathematical models Data models

A Self-Calibration Logic Circuit Agnostic To Offset Calibration Technique For High-Precision Dynamic Comparator

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A Self-Calibration Logic Circuit Agnostic To Offset Calibrat...

Women in Technology Conference (WINTECHCON), 2022 IEEE

作者： Nidhi Sharma Rajesh K. Srivastava Vinayak Hande Deep Sehgal Devarshi Mrinal Das Department of Electrical Engineering Indian Institute of Technology Ropar Rupnagar India Semi-conductor Laboratory Ministry of Electronics & Information Technology (MeitY) S.A.S Nagar India Integrated Systems and Circuit Design Carinthia University of Applied Sciences Villach Austria

This paper proposes a calibration technique agnostic calibration logic circuitry for the self-calibration of the high-precision dynamic comparator, which can be used in major self-calibration techniques to activate the calibration and offset polarity change detection for completion of the calibration. This paper also briefly reviews the different comparator offset cancellation techniques, i.e., auto-zeroing, self-calibration, and chopper stabilization. The proposed calibration logic is implemented in a dynamic comparator’s effective trans-conductance controlled offset calibration in SCL 180 nm technology. The standard deviation of the input-referred offset of the comparator is reduced to 445 μV from 2.85 mV with a complete calibration range of 5σ offset, therefore qualifying it for high-speed flash ADCs and asynchronous SAR ADCs. The power consumption at 1 GHz operating frequency is 154.6 μW.

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Low Voltage Ride Through Based On Hydrogen Energy Storage for Improving Performance of Wind Energy Conversion System Under Grid Faults

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Low Voltage Ride Through Based On Hydrogen Energy Storage fo...

Innovative Research in Applied Science, engineering and Technology (IRASET),Conference on

作者： Mohamed Makhad Khalida Zazi Abdelilah Hilali Azeddine Loulijat Mouncef El Marghichi Department of Electrical Engineering ENSEM-Rabat Mohammed V university in Rabat Rabat Morocco Electronics Communication Systems and Energy Optimization Team Faculty of Sciences Moulay Ismail University Meknes Morocco Faculty of Sciences and Technology Hassan First University Settat Morocco Intelligent Systems Design Laboratory (ISDL) Faculty of science Abdelmalek Essaadi University Tetouan Morocco

ISBN: (数字)9798350309508

ISBN: (纸本)9798350309515

With the rapid growth of renewable energy projects, leading to high integration of wind energy conversion systems (WECS) into the power grid, several challenges have emerged. In recent years, these issues have taken on high priority in order to guarantee the stability, reliability and security of the electrical grid. Thus, to address urgently these issues, almost all countries have updated their grid codes to include new requirements relating to grid-connected WECS. Low voltage ride through (LVRT) capability is one of the first specifications imposed to define the operating mode of wind farms during and in post-grid fault conditions. This paper presents a cost-effective hydrogen energy storage system (HESS) for regulating the DC-link voltage of WECS based on permanent magnet generator (PMSG) under grid faults. This hardware approach is combined with the modified control scheme of the grid-side converter (GSC) for reducing the second-order oscillations that occur in the event of an asymmetrical grid fault, and for injecting reactive power into the grid in accordance with the grid code requirements. To validate the proposed approach, the entire system is modeled in MATLAB/Simulink. The simulation results show that HESS is perhaps a future solution for improving the LVRT capability of PMSG-WECS.

关键词： Protons Low voltage Codes Hydrogen Wind farms Hardware Wind turbines