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IEEE International Conference on High Performance Computing and Communications (HPCC)

作者： Yijia Wu Congpin Zhang Zhengwei Xu Ligang Li National Space Science Center Key Laboratory of Electronics and Information Technology for Space System Chinese Academy of Sciences Beijing China School of Computer Science and Technology University of Chinese Academy of Sciences School of Computer & Information Engineering Henan Normal University Xinxiang Henan China

Physically based ray tracing is a technique that involves creating a photo-realistic image from a 3D scene description by utilizing the laws of physics to simulate the behavior of light and matter. However, due to the random length of light samples and irregular memory access patterns, it can suffer from low scalability and severe load imbalance. As a result, the development of a framework for multi-node parallelism algorithm in physically based ray tracing is a significant challenge. To tackle these issues, this paper introduces a novel algorithm named distributed parallel physically based bidirectional path tacing algorithm (DP-BDPT). Through analyzing the physical essence of bidirectional path tracing algorithm and the light transport equation, we have devised a framework that carefully divides tasks between inter-compute nodes and intra-compute nodes. To support high scalability, we have developed a physically based architecture. Additionally, we have proposed a hybrid scheduling method to achieve load balancing. To further enhance performance, we have analyzed several key factors that affect rendering performance and implemented adaptive optimization techniques. The experiments conducted on the Tianhe-2 Supercomputer involving typical and challenging 3D scenes, namely the Cornell-box, Veach-bidir, and Teapot-full experiments, have illustrated that DP-BDPT demonstrate near-linear speedups as the number of CPU cores scales from 1200 to 9600, thereby demonstrating their efficiency when operating on a ten-thousand-core system.

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Fault Ride-through Control of Grid-Forming Converters under Different Fault States

Fault Ride-through Control of Grid-Forming Converters under ...

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2022 IEEE International Conference on Power systems and Electrical technology, PSET 2022

作者： Ming, Zhong Rulei, Han Yi, Yang Xiaolei, Bai Co. Ltd. Inner Mongolia Power Research Institute Branch Hohhot010020 China Inner Mongolia Enterprise Key Laboratory of Smart Grid Simulation of Electrical Power System Hohhot010020 China Inner Mongolia University School of Physical Science and Technology Hohhot010021 China

ISBN: (纸本)9781665489157

Grid-forming (GFM) converters are one of the main components of the power electronic equipment with high permeability, and their fault-ride through (FRT) capability is an important basis to ensure the stable operation of highly electronic power system. Based on this, this paper proposes an FRT strategy for GFM converters, which not only considers the hardware constraints (i.e., current constraints) of the converters, but also can keep GFM converters running in the protected mode under symmetric and asymmetric faults. Firstly, the FRT of GFM converter is analyzed in detail. Then, an appropriate FRT model and control method are established. Finally, the effectiveness of the proposed method is verified by power-hardware-in-the-loop (PHIL) simulation and experiment. The results show that compared with GFL, the proposed control method can guarantee the instantaneous injection of reactive current when the GFM converter fails to prevent the overcurrent problem. Finally, the GFM converter can still operate fault-tolerantly under severe fault conditions. © 2022 IEEE.

关键词： Oscillators (electronic)

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High Abundance of Atmospheric Sulfonates Derived from Light-Duty Gasoline Vehicles

ACS ES&T Air

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ACS ES&T Air 2025年第4期2卷 607-614页

作者： Shuang Chen Huixia Han Lihong Ren Yisheng Xu Libin Wu Yuanguan Gao Yuanbi Yi Xinping Yang Mingliang Fu Hang Yin Yan Ding Pingqing Fu State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental Sciences Beijing 100012 China；School of Earth System Science Tianjin University Tianjin 300072 China School of Earth System Science Tianjin University Tianjin 300072 China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental Sciences Beijing 100012 China Department of Ocean Science and Center for Ocean Research in Hong Kong and Macau The Hong Kong University of Science and Technology Hong Kong SAR China State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation Chinese Research Academy of Environmental Sciences Beijing 100012 China

Particulate matter (PM) emissions from light-duty gasoline vehicles (LDGV) pose a threat to both air quality and human health. However, the molecular compositions and chemical properties of these complex mixtures are poorly understood. In this study, we performed a detailed characterization of exhaust PM from LDGV at various speed phases at the molecular level by employing ultra-high-resolution Fourier transform ion cyclotron resonance mass spectrometry. We found that with increasing speed, the number of organic compounds increased significantly, especially organic nitrogen-containing and sulfur-containing compounds. Moreover, the increase of speed leads to high temperature and high pressure in the cylinder, which in turn leads to a series of thermal cracking–polymerization–cyclization reactions, resulting in new particulate matter with more aromatic structures. In addition, considerable intermediate volatility organic compounds and semivolatile organic compounds were identified in the exhaust PM. Notably, we observed the presence of sulfonates in tailpipe particulate matter during low- or high-speed phases, which highlights a previously negligible source of organic sulfonates in the atmosphere.

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Pin-Tool based execution backtracking 13th

Pin-Tool based execution backtracking

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13th Conference on Advanced Computer Architecture, ACA 2020

作者： Wei, Shuangjian Ji, Weixing Chen, Qiurui Wang, Yizhuo Beijing Institute of Technology Beijing100081 China Science and Technology on Special System Simulation Laboratory Beijing Simulation Center Beijing100854 China

ISBN: (纸本)9789811581342

Checkpoint/restart is a common fault tolerant technique which periodically dump state to reliable storage and restart applications after failure. Most of existing checkpoint/restart implementations only handle volatile state and lack of support for persistence state of applications. Even the algorithm specifically designed for file checkpointing may not support complex operations and some need to modify source code. This paper presents a new checkpoint technique, which use dynamic instrumentation to temporarily cache disk operations in memory, and use existing memory checkpoint tool to dump or restore process state at runtime. We show that not only can this method create regular checkpoints for both volatile and persistence state, but also has important applications in execution backtracking. © Springer Nature Singapore Pte Ltd 2020.

关键词： Cache memory

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Towards Finite Blocklength Covert Communications via A Jammer Mounted on A UAV

Towards Finite Blocklength Covert Communications via A Jamme...

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IEEE International Conference on Communications in China (ICCC)

作者： Xinyu Guo Yida Wang Yong Luo Changbiao Lei Leizhen Xie Tianyu Jia School of Electronic Science and Engineering University of Electronic Science and Technology of China Chengdu China Academy of Military Science of PLA Institute of System Engineering Beijing China Laboratory of Electromagnetic Space Cognition and Intelligent Control Beijing China PLA Troop of 32027 Kaifeng China

ISBN: (数字)9798350378412

ISBN: (纸本)9798350378429

In this work, we focus on covert communications via a jammer mounted on an unmanned aerial vehicle (UAV) under the supervision of a warden with finite blocklength, i.e., with the short delay constraint. Specifically, we analytically derive the Kullback-Leibler (KL) divergence to obtain a tight lower bound of the sum of the warden’s detection error probabilities, which can be used to characterize the covertness constraint. Then, we derive the communication outage probability to evaluate the communication quality. From the perspective of the aerial jammer, we jointly optimize its transmit power and hovering height to minimize the communication outage probability under the covertness constraint. The optimal aerial jammer’s hovering height is affected by the relation of the distances between the receiver/warden and the aerial jammer, and the optimal aerial jammer’s transmit power is forced to increase when facing stricter covertness requirement, larger blocklength or larger information transmit power.

关键词： Error probability Autonomous aerial vehicles Power system reliability Delays Security Jamming Optimization

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ACCELERATED PERFORMANCE DEGRADATION TEST AND ANALYSIS OF HIGH-TEMPERATURE STRAIN GAUGES 13

ACCELERATED PERFORMANCE DEGRADATION TEST AND ANALYSIS OF HIG...

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13th International Conference on Quality, Reliability, Risk, Maintenance, and Safety Engineering, QR2MSE 2023

作者： Li, Lu Wang, Zhihua Yang, Ning Wu, Qiong Wang, Hanyue Mao, Zelong Ren, Kunpeng Wang, Qiuyue Wang, Yifeng National Key Laboratory of Strength and Structural Integrity School of Aeronautic Science and Engineering Beihang University Beijing China Shenyang Aircraft Design and Research Institute Shenyang China Institute of Spacecraft System Engineering China Academy of Space Technology Beijing China Navigation Instrument Research Institute Tianjin China Beijing Institute of Control Engineering Beijing China

ISBN: (纸本)9781839539848

With the extension of the service time of the structure and the worse service temperature conditions, the drift problem of high-temperature strain gauges gradually becomes prominent. This research aims to address the issue of the drift of measurement results because of the performance degradation of high-temperature strain gauges, and investigate the drift law under different temperatures considering complex service environments. In this paper, a combination of experimental research and theoretical analysis is utilized to design and conduct the accelerated performance degradation test on high-temperature strain gauges. Based on the result of the test, an accelerated performance degradation model is developed using the Wiener process and Arrhenius model. Finally, estimation curves for the average value and percentile value of the performance parameters of the high-temperature strain gauges are obtained, which demonstrates that the established accelerated performance degradation model can reasonably describe the degradation law. Additionally, the established accelerated performance degradation model enables effective analysis and compensation of gauge drift at any temperature. © The Institution of Engineering & technology 2023.

关键词： Strain gages

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Future climate change decreases multi-pathway but increases respiratory human health risks of PAHs across China

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National science Open 2024年第2期3卷 128-147页

作者： Jiaao Bao Xinghui Xia Ying Zhu Bingxiang Zhao Erxue Gu Yanan Liu Xiao Yun Zhenrui Zhang Nannan Xi Yong Geng Ying Xu Zhifeng Yang Derek C.G.Muir Key Laboratory of Water and Sediment Sciences of Ministry of Education State Key Laboratory of Water Environment SimulationSchool of EnvironmentBeijing Normal UniversityBeijing 100875China State Environmental Protection Key Laboratory of Environmental Health Impact Assessment of Emerging Contaminants School of Environmental Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China College of Urban and Environmental Sciences Laboratory for Earth Surface ProcessesSino-French Institute for Earth System SciencePeking UniversityBeijing 100871China National Climate Center China Meteorological AdministrationBeijing 100081China Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education Institute of Environmental and Ecological EngineeringGuangdong University of TechnologyGuangzhou 510006China Aquatic Contaminants Research Division Environment and Climate Change CanadaBurlington L7S 1A1Canada

Future climate change will affect the environmental fate of hydrophobic organic contaminants(HOCs)and associated human health risks,yet the extent of these effects remains ***,we couple a high-resolution environmental multimedia model with a bioaccumulation model to study the multimedia distribution of 16 priority polycyclic aromatic hydrocarbons(PAHs),a group of HOCs,and assess future PAH-related human health risks under varying climate change scenarios over China at a continental *** removing the effects of PAH emission changes,we find that the total PAH concentrations would decrease in the air,freshwater,sediment,soil,and organisms,while the high-molecular-weight PAH would increase in the air with climate warming from 1.5°C to 4°***,the multi-pathway exposure human health risks predominately influenced by dietary ingestion are expected to decrease by 1.7%–20.5%,while the respiratory risks are projected to rise by 0.2%–5.8%in the ***,the persistently high multi-pathway human health risks underscore the need for reducing future PAH emissions by 69%compared with 2009 levels in *** study demonstrates the urgency of limiting PAH emissions under future climate change for public health and highlights the importance of including the contribution of dietary ingestion in human health risk assessment.

关键词： polycyclic aromatic hydrocarbons future climate change human health risks emission reduction

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Combined active and passive adaptive variable admittance compliant control for space robotic manipulators

Combined active and passive adaptive variable admittance com...

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IEEE International Conference on Robotics and Biomimetics

作者： Hang Gao Xiaodong Zhang Chao Ma Cheng Zhou School of Mechanical Engineering University of Science and Technology Beijing Beijing China Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Application Beijing Institute of Spacecraft System Engineering CAST China

This paper develops a combined active and passive adaptive variable admittance compliant control algorithm for space robotic manipulators. In fact, the assembly task for space robots requires compliance and precision while ensuring avoidance of any occurrences of rigid collision throughout the process. Therefore, we design a new combined active and passive variable admittance control structure combined with the following three parts to meet these acquirements. Firstly, we develop an active variable admittance algorithm to facilitate the space robot rapid movement, enabling it to achieve higher speeds while maintaining compliance. Then, to mitigate the occurrence of unforeseen rigid collisions during the robot motion, we devise a passive variable admittance control algorithm, which aims to minimize the impact of collision events and ensure the robot safe operation. Furthermore, by employing the Lyapunov theory, a new active adaptive variable admittance control algorithm is presented for robot constant force output. Consequently, through contrast experiments, we demonstrate the effectiveness and enhanced performance of the proposed algorithm.

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The Analysis and Compensation of Elastic Unbalance Torque of the Three-axis Air-bearing Simulator 5

The Analysis and Compensation of Elastic Unbalance Torque of...

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2021 5th International Conference on Electrical, Automation and Mechanical Engineering, EAME 2021

作者： Li, Zhanxin Cao, Zizhen Duan, Wenjie Du, Yikang Liu, Haiteng Tianjin Institute of Aerospace Mechanical and Electrical Equipment Tianjin China Tianjin Key Laboratory of Microgravity Environment Simulation Technology Tianjin China Beijing Institute of Control Engineering Beijing China Science and Technology on Space Intelligent Control Laboratory Beijing China

The most important interfering torque of a three-axis air-bearing simulator is the displacement of the center of mass in the gravity field caused by structural elasticity. In order to characterize the torque, a mathematical model of the interference moment was established. Based on the model, it is suggested that the vertical stiffness and horizontal stiffness of the structure should be equal as far as possible during the structural design, and the elastic unbalance moment can be compensated by the vertical offset of the center of mass of the air floating platform relative to the rotation center after the initial attitude leveling. ABAQUS was used to build a simulation model of the air floating platform, and the changes of the structure's centroid before and after the gravitational field was applied were extracted by software to simulate the centroid deviation caused by the elastic deformation of the structure, which was used as the characterization to conduct discrete optimization of the structure. The optimal structural parameters were obtained. Then the disturbance torque curve and the corresponding initial centroid offset after initial centroid compensation were calculated by mathematical model. The results are of positive guiding significance to the design of three-axis air-bearing simulator. © 2021 Institute of Physics Publishing. All rights reserved.

关键词： Torque

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Microstrip-Ridge Gap Waveguide Layer Transition for Compact Wave-guide Packaging Interconnection 9

Microstrip-Ridge Gap Waveguide Layer Transition for Compact ...

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9th IEEE MTT-S International Wireless Symposium, IWS 2022

作者： Wang, Hui Feng, Wenjie Shi, Yongrong Nanjing University of Science and Technology Department of Communication Engineering Nanjing210094 China South China University of Technology Guangdong Provincial Key Laboratory of Millimeter-Wave and Terahertz Guangzhou510006 China Nanjing University of Aeronautics and Astronautics Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information Technology Nanjing210044 China

ISBN: (数字)9781665481977

ISBN: (纸本)9781665481977

For millimeter-wave integrated circuit packaging and interconnection application, a microstrip-ridge gap wave-guide (MRGW) layer transition structure is proposed. MRGW consists of an array of mushroom units and the microstrip line which is shorted to the ground plane. Above the layer of MRGW, there is the layer transition, including a substrate integrated waveguide (SIW) resonant cavity and the tapered microstrip line, which is composed to achieve impedance matching and the field coupling between the MRGW and the microstrip line. Full-wave simulation software is used to design and simulate the back-to-back layer transition. The numerical simulation results indicates that the proposed transition operates at 64.8-76.5GHz, with the return loss vert mathrm{S}-{11} vert higher than 15 dB. © 2022 IEEE.

关键词： Cavity resonators

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