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AIAA science and technology Forum and Exposition, AIAA SciTech Forum 2025

作者： Murayama, Shingo Takahashi, Masaki Fukuda, Seisuke School of Science for Open and Environmental Systems Keio University 3-14-1 Hiyoshi Kohoku-ku Kanagawa Yokohama223-8522 Japan Faculty of Science and Technology Department of System Design Engineering Keio University 3-14-1 Hiyoshi Kohoku-ku Kanagawa Yokohama Japan Department of Spacecraft Engineering Institute of Space and Astronautical Science Japan Aerospace Exploration Agency Kanagawa Sagamihara252-5210 Japan

ISBN: (数字)9781624107238

ISBN: (纸本)9781624107238

Active debris removal has become crucial. The removal of the upper stages of the rocket, which are the most common type of debris, is receiving increased attention. In the case of debris removal from the upper stage of a rocket, it is considered to recognize the circular structure of the upper stage of the rocket, which appears as an ellipse on the image plane, as a payload attach fitting (PAF) using the navigation sensor, and to approach it. Approaching the debris requires tracking the ellipses during the approach after initially recognizing the inner and outer ellipses of the PAF. Thus, the navigation sensor must be robust to sunlight for stable ellipse recognition. Consequently, we propose an initial PAF recognition method using an event camera due to its robust features as a navigation sensor. In the initial recognition, image processing is applied to event frames that accumulate asynchronous output events. As the inner ellipse of the PAF is suitable for feature extraction, we proposed a method to recognize the outer ellipse using the value of the inner ellipse after initial recognition of the inner ellipse. Additionally, when the recognition of the inner or outer ellipse fails, we propose extending the event accumulation time and repeating the process. The effectiveness of the proposed method was verified by numerical analysis using a simulator. © 2025, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Rockets

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Towards Scalable and Privacy-Preserving Data Sharing in Internet of Digital Twins

Towards Scalable and Privacy-Preserving Data Sharing in Inte...

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IEEE Conference on Global Communications (GLOBECOM)

作者： Xiangyu Shi Guanjie Li Tom H. Luan Zhou Su Shui Yu Wen Wu School of Cyber Engineering Xidian University Xi’an China Information System Technology and Design Pillar Singapore University of Technology and Design Singapore School of Cyber Science and Engineering Xi’an Jiaotong University Xi’an China School of Computer Science University of Technology Sydney Sydney Australia Frontier Research Center Peng Cheng Laboratory Shenzhen China

ISBN: (数字)9798350351255

ISBN: (纸本)9798350351262

A Digital Twin (DT) is a software agent of a physical entity in virtual space, transcending the limitations imposed by physical constraints to enable intelligent services. The emergence of the Internet of Digital Twins (IoDT), by connecting DTs as a network, provides a reliable solution for streamlining the sharing of extensive real-time data among DTs. However, ensuring the security and efficiency of highly sensitive DT data remains a significant challenge in the distributed and dynamic IoDT storage environment. In this paper, we propose a comprehensive scheme that integrates blockchain, Distributed Hash Table (DHT), and Attribute-Based Encryption (ABE) to establish an IoDT data-sharing system. First, we introduce an ABE scheme to achieve data confidentiality and fine-grained access control. By implementing a key generation protocol, we address key escrow concerns in ABE. Second, to ensure bidirectional data confidentiality in data sharing without revealing the identities of DTs, the DHT, and blockchain are jointly applied to achieve resource registration and discovery. Through an XOR mapping operation mechanism, DT data are distributed across different DHT network nodes, reducing DT nodes’ storage consumption and effectively addressing the scalability issue of IoDT storage. Finally, we provide performance evaluations to demonstrate the reliability and efficiency of our proposed scheme. Our scheme strikes a balance between efficiency and security, exhibiting efficient performance in IoDT data sharing compared to other ABE and blockchain schemes.

关键词： Access control Data privacy Scalability Software agents Real-time systems Blockchains Digital twins Internet Encryption Software reliability

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Learning to Synchronize with Chaotic Dynamical systems Using Time-Delayed Reservoir Computing

SSRN

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SSRN 2023年

作者： Xiao, Bo Liang, Jiqiu Cai, Lun Wu, Dan Sun, Jiaji Zhang, Bin Li, Renfu School of Mechanical Engineering Huazhong University of Science and Technology Wuhan China System Design Institute Hubei Areospace Technology Academy Wuhan430040 China School of Aerospace Engineering Huazhong University of Science and Technology Wuhan China

Reservoir computing (RC) is a class of simple but efficient neural networks that is particularly suited for temporal or sequential learning tasks. The prediction of chaotic dynamical systems using RC has been well recognized in the literature. This article studies the time-delayed reservoir computing (TDRC), where delayed reservoir state is concatenated through time for predicting chaotic dynamics. We calculate the Lyapunov spectrum of the trained reservoir, with either intermittent access to the input chaotic systems or not. It is found that the Lyapunov spectrum does not necessarily match with that of the input chaotic systems for good prediction. We demonstrate the results on simulations of Lorenz-63 and Lorenz-96 system, and 1D Kuramoto-Sivashinsky system. © 2023, The Authors. All rights reserved.

关键词： Time delay

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A General Iterative Extended Kalman Filter Framework for State Estimation on Matrix Lie Groups

A General Iterative Extended Kalman Filter Framework for Sta...

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IEEE Conference on Decision and Control

作者： Ben Liu Hua Chen Wei Zhang Shenzhen Key Laboratory of Control Theory and Intelligent Systems Southern University of Science and Technology Shenzhen China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China

In this paper, we focus on state estimation problem for nonlinear systems on joint matrix Lie group and Euclidean space We propose a general iterative Kalman filter, aiming to integrate the prediction step into the iteration scheme, which is not considered in the conventional iterative extended Kalman filter framework. Such an extra iteration scheme in the prediction step helps improving the accuracy of probability density function propagation through nonlinearities, which can further lead to more accurate estimations of the system states. In addition, the proposed framework unifies the Kalman filter based estimation schemes on studied manifold by adopting the perspective from Gaussian Bayesian inference. The improvement of the proposed framework is illustrated by the ES-GIKF algorithm that is instantiated from the proposed framework in a numerical simulation.

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Mechanical Properties and Thermal Shock Resistance of SrAl_(2)Si_(2)O_(8) Reinforced BN Ceramic Composites

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无机材料学报 2024年第10期39卷 1182-1188页

作者： WANG Bo CAI Delong ZHU Qishuai LI Daxin YANG Zhihua DUAN Xiaoming LI Yanan WANG Xuan JIA Dechang ZHOU Yu International Joint Laboratory of Advanced Nanomaterials of Heilongjiang Province College of Materials Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001China Key Laboratory of Advanced Structural-Functional Integration Materials School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China China Resources Cement Technology R&D Co. LtdGuangzhou 510000China The First Military Representative Office of the Army Equipment Department in Beijing Beijing 100072China The Fourth System Design Department Fourth AcademyChina Aerospace Science and Industry Corporation LimitedBeijing 100048China School of Materials Science and Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China

Hexagonal boron nitride(h-BN)ceramics have become exceptional materials for heat-resistant components in hypersonic vehicles,owing to their superior thermal stability and excellent dielectric ***,their densification during sintering still poses challenges for researchers,and their mechanical properties are rather *** this study,SrAl_(2)Si_(2)O_(8)(SAS),with low melting point and high strength,was introduced into the h-BN ceramics to facilitate the sintering and reinforce the strength and ***,BN-SAS ceramic composites were fabricated via hot press sintering using h-BN,SrCO_(3),Al_(2)O_(3),and SiO_(2) as raw materials,and effects of sintering pressure on their microstructure,mechanical property,and thermal property were *** thermal shock resistance of BN-SAS ceramic composites was *** show that phases of as-preparedBN-SAS ceramic composites are h-BN and h-SrAl_(2)Si_(2)O_(8).With the increase of sintering pressure,the composites’densities increase,and the mechanical properties shew a rising trend followed by a slight *** a sintering pressure of 20 MPa,their bending strength and fracture toughness are(138±4)MPa and(1.84±0.05)MPa·m^(1/2),*** sintered at 10 MPa exhibit a low coefficient of thermal expansion,with an average of 2.96×10^(-6) K^(-1) in the temperature range from 200 to 1200℃.The BN-SAS ceramic composites prepared at 20 MPa display higher thermal conductivity from 12.42 to 28.42 W·m^(-1)·K^(-1) within the temperature range from room temperature to 1000℃.Notably,BN-SAS composites exhibit remarkable thermal shock resistance,with residual bending strength peaking and subsequently declining sharply under a thermal shock temperature difference ranging from 600 to 1400℃.The maximum residual bending strength is recorded at a temperature difference of 800℃,with a residual strength retention rate of 101%.As the thermal shock temperature difference increase,the degree of oxida

关键词： BN matrix composite hot-press sintering mechanical property thermal shock resistance service reliability

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Revealing the Trade-off in ISAC systems: The KL Divergence Perspective

arXiv

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arXiv 2024年

作者： Fei, Zesong Tang, Shuntian Wang, Xinyi Xia, Fanghao Liu, Fan Zhang, J. Andrew The School of Information and Electronics Beijing Institute of Technology Beijing100081 China The School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China The School of Electrical and Data Engineering University of Technology SydneyNSW2007 Australia

Integrated sensing and communication (ISAC) is regarded as a promising technique for 6G communication network. In this letter, we investigate the Pareto bound of the ISAC system in terms of a unified Kullback-Leibler (KL) divergence performance metric. We firstly present the relationship between KL divergence and explicit ISAC performance metric, i.e., demodulation error and probability of detection. Thereafter, we investigate the impact of constellation and beamforming design on the Pareto bound via deep learning and semi-definite relaxation (SDR) techniques. Simulation results show the tradeoff between sensing and communication performance in terms of bit error rate (BER) and probability of detection under different parameter set-ups. Copyright © 2024, The Authors. All rights reserved.

关键词： Beamforming

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A Method of Predicting Posture-related Pain Using Biomechanical Parameters for Patients with Lumbar Spinal Disc Herniation

A Method of Predicting Posture-related Pain Using Biomechani...

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Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

作者： Airi Hatsushiro Yuta Tawaki Toshiyuki Murakami Graduate School of Science and Technology Keio University Yokohama Japan Department of System Design Engineering Keio University Yokohama Japan

Lumbar spinal disc herniation is a disease in which the protruding nucleus pulposus presses on the nerve due to actions that place loads on the disc, causing pain in the lower back and lower limbs. About 80% of treatments of disc herniation are conservative treatments, and although it is necessary to live with pain for a long time, there have been no studies that clearly define the relationship between pain and biomechanical parameters. In this study, we proposed a method of identifying biomechanical parameters that predict posture-related pain in patients with lumbar spinal disc herniation. The pain values were quantitatively evaluated by the Numerical Rating Scale (NRS) and the biomechanical parameters were analyzed by OpenSim. Lasso regression was performed to narrow down the biomechanical parameters that were related to pain and derive the mathematical model of the relationship. Therefore, many of the parameters of the obtained mathematical model were related to the lumbar spine and were consistent with areas that be related to lumbar spinal disc herniation.

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Numerical study of fuel melting and molten migration based on the mps method

Numerical study of fuel melting and molten migration based o...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Lei, Zhong Deng, Jian Li, Wei Wu, Xiaoli Deng, Chunrui Nuclear Power Institute of China Chengdu Sichuan China Science and Technology on Reactor System Design Technology Laboratory Chengdu Sichuan China

ISBN: (纸本)9780791883785

Core melting and molten migration behavior are hot and difficult issues in the field of nuclear reactor severe accident research. The Moving Particle Semi-implicit (MPS) meshless method has potential to simulate free-surface and multiphase flows. In this study, the MPS method was utilized to simulate the melting process of UO2-Zr rod-type fuel elements. The models of heat conduction with phase change, simplified UO2-Zr eutectic reaction, viscous flow and surface tension were implemented with the framework of standard MPS method. Then, the improved MPS code was used to simulate and analyze the process of high-temperature melting and characteristics of molten migration and solidification in the coolant channel, aiming at revealing the severe accidents for light water reactors (LWR), particularly the early core damage. The results showed that compared with the case of higher initial temperature, when the initial temperature of molten UO2 is lower, more molten UO2 will solidify on the surface of rod cluster, and the blockage of upper flow channel caused by molten UO2 is more serious. In addition, this study also demonstrated the potential of the MPS method for the study of complicated severe accident phenomena in not only traditional LWR but also advanced nuclear reactors in the future. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Solidification

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Study on the liquid seal discharge process in an over-pressurized accident

Study on the liquid seal discharge process in an over-pressu...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Wu, Dan Deng, Jian Du, Sijia Qian, Libo Nuclear Power Institute of China Chengdu Sichuan China Science and Technology on Reactor System Design Technology Laboratory Chengdu Sichuan China

ISBN: (纸本)9780791883785

In an over pressure accident, one or more pressurizer safety(or relief) valves will open due to the rapid pressure rise process. Once the safety(or relief) valves are open, the liquid seal will be discharged, and this will generate great discharge force to the downstream pipes. Multi-level protection is chosen using pressurizer safety(or relief) valves with different setpoint in most of Nuclear Power Plant, especially in the self-designed Generation-III Nuclear Power Plants. As the over pressure accident progresses, one or more safety(or relief) valves will be open. The downstream pipes will experience one or more times of impacts, which will influence the arrangement of the pipes. The whole discharge process is very complex, and the key influence factors are the pressure rise rate, safety(or relief) valve opening time, liquid seal temperature and volume, and the arrangement of the downstream discharge pipes. In present paper, liquid seal discharge process in an over pressure accident is studied. The pressure rise rate is so fast that three safety(or relief) valves will open one after another, which will generate three impacts on the downstream discharge pipes. It is found that for a specific design of Nuclear Power Plant, well design of the safety(or relief) valve setpoint is very important to the discharge force analysis results. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Liquids

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High-Performance Multipliers and Adder designs in Digital Filters

High-Performance Multipliers and Adder Designs in Digital Fi...

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International Conference on Computer and Applications (ICCA)

作者： Thanmai Thota Minyue Fu Graduate Signal Engineer Australian Rail Track Corporation Newcastle Australia School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China

ISBN: (数字)9798350367560

ISBN: (纸本)9798350367577

Very Large-Scale Integration (VLSI) industries demand efficient multiplier designs for Digital Signal Processors. Research on multipliers has taken different paths to improve the efficiency of a multiplier in various parameters. This paper presents new efficient 8*8 multiplier designs namely the Weinberger Multiplier (Weinberger Adder-based Multiplier) and Composite Multiplier (Weinberger and Full Adder-based Multiplier). This paper also presents their implementation in a 5th-order transpose form FIR filter. Using 32nm technology in Cadence Virtuoso, the power, area, and delay values of the multipliers are presented. Furthermore, CMOS and GDI techniques are adopted to design multipliers at the transistor level. These two techniques have their advantages and drawbacks. CMOS technique is proven to be the best technique to adopt when the average power of the circuit is of primary concern but has circuit area and delay issues. The GDI technique is the best choice to improve efficiency in terms of area and delay but has the drawback of full swing at the output. To address the drawbacks of CMOS and GDI techniques and improve multipliers' efficiency in terms of power, area, and delay, intermixing the two techniques is adopted as the best choice for multipliers and filter designs. CMOS+GDI based Weinberger multiplier is 32.4%, 18.94%, and 30% efficient in transistor count, maximum power, and delay, respectively, compared to CMOS. CMOS+GDI based Composite multiplier is 65.2%, 43.1 %, and 91.22% efficient in transistor count, maximum power, and delay, respectively, compared to CMOS.

关键词： Industries Finite impulse response filters Digital signal processors Very large scale integration CMOS technology Delays Transistors Adders

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