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21st International Bhurban Conference on Applied Sciences and Technology, IBCAST 2024

作者： Rafay, Abdul Maqsood, Adnan National University of Sciences & Technology Research Center for Modeling & Simulation Islamabad44000 Pakistan

ISBN: (纸本)9798331516680

The stability coefficients and derivatives are used to determine a vehicle's motion and are considered critical for the design of flight vehicles. In this research, the dynamic pitch derivatives of an axisymmetric projectile prototype are examined using Computational Fluid Dynamics (CFD). For this purpose, a methodology is established by validating two test cases and then applied to a newly designed prototype. The dynamic damping derivatives are calculated using the forced oscillation approach. The pitch damping coefficients are simulated for angles of attack from 0° to 20°. A decent agreement is observed between the CFD and experimental data. The test cases are also analyzed through DATCOM for comparative analysis. A conceptual projectile geometry is designed and evaluated at a Mach number of 1.5. A parametric analysis is also conducted for the variation of Mach number and reduced pitch rate on pitch damping coefficients for the conceptual geometry. This study establishes the use of CFD to determine fast and consistent estimates for the aerodynamic stability parameters. © 2024 IEEE.

关键词： Computational fluid dynamics

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An Intelligent Ranking Evaluation Method of simulation Models Based on Graph Neural Network 15th

An Intelligent Ranking Evaluation Method of Simulation Model...

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15th EAI International Conference on simulation Tools and Techniques, SIMUTools 2023

作者： Yang, Fan Ma, Ping Zhang, Jianchao Cheng, Huichuan Li, Wei Yang, Ming Control and Simulation Center Harbin Institute of Technology Harbin150080 China National Key Laboratory of Complex System Modeling and Simulation Harbin150080 China Chinese Aeroengine Research Institute Beijing101304 China

ISBN: (纸本)9783031575228

To validate the alternative simulation models and select the most credible one when the models have multivariate and correlated outputs, an intelligent ranking evaluation method of simulation models based on Graph Neural Network (GNN) is proposed. The process of ranking evaluation is divided into three parts: graph structure conversion for evaluation data, feature extraction based on Graph Representation Learning (GRL) and ranking evaluation based on feature distance. A graph structure modeling method is presented to provide the pre-define graph structure for further GRL primarily. Next the interdependencies and dynamic evolutionary patterns among variables are captured by GNN so that the graph representations of evaluation data can be obtained. Then ranking evaluation is achieved by similarity measurement of the graph representations. In the end, the effectiveness of the proposed method on feature extraction of evaluation data and simulation models ranking is illustrated through an application example on a prediction model for aerodynamic parameters of a certain flight vehicle. © ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering 2024.

关键词： Feature extraction

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Flight Mechanics of a Supersonic Projectile: A Parametric Investigation

Flight Mechanics of a Supersonic Projectile: A Parametric In...

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International Bhurban Conference on Applied Sciences & Technology, IBCAST

作者： Abdul Rafay Adnan Maqsood Research Center for Modeling & Simulation National University of Sciences & Technology Islamabad Pakistan

ISBN: (数字)9798331516680

ISBN: (纸本)9798331516697

关键词： Damping Geometry Computational fluid dynamics Projectiles Computational modeling Prototypes Aerodynamics Stability analysis Vehicle dynamics Oscillators

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APT Adversarial Defence Mechanism for Industrial IoT Enabled Cyber-Physical System

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IEEE Access 2023年 11卷 74000-74020页

作者： Javed, Safdar Hussain Ahmad, Maaz Bin Asif, Muhammad Akram, Waseem Mahmood, Khalid Das, Ashok Kumar Shetty, Sachin College of Computing and Information Sciences Karachi75190 Pakistan Lahore Garrison University Department of Computer Science Lahore54810 Pakistan National Yunlin University of Science and Technology Graduate School of Intelligent Data Science Douliu64002 Taiwan International Institute of Information Technology at Hyderabad Center for Security Theory and Algorithmic Research Hyderabad500032 India Old Dominion University Simulation and Visualization Engineering Virginia Modeling Analysis and Simulation Center Department of Modeling SuffolkVA23435 United States Old Dominion University Center for Cybersecurity Education and Research SuffolkVA23435 United States

The objective of Advanced Persistent Threat (APT) attacks is to exploit Cyber-Physical Systems (CPSs) in combination with the Industrial Internet of Things (I-IoT) by using fast attack methods. Machine learning (ML) techniques have shown potential in identifying APT attacks in autonomous and malware detection systems. However, detecting hidden APT attacks in the I-IoT-enabled CPS domain and achieving real-time accuracy in detection present significant challenges for these techniques. To overcome these issues, a new approach is suggested that is based on the Graph Attention Network (GAN), a multi-dimensional algorithm that captures behavioral features along with the relevant information that other methods do not deliver. This approach utilizes masked self-attentional layers to address the limitations of prior Deep Learning (DL) methods that rely on convolutions. Two datasets, the DAPT2020 malware, and Edge I-IoT datasets are used to evaluate the approach, and it attains the highest detection accuracy of 96.97% and 95.97%, with prediction time of 20.56 seconds and 21.65 seconds, respectively. The GAN approach is compared to conventional ML algorithms, and simulation results demonstrate a significant performance improvement over these algorithms in the I-IoT-enabled CPS realm. © 2013 IEEE.

关键词： Real time systems

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CONSTRAINED BI-LEVEL OPTIMIZATION: PROXIMAL LAGRANGIAN VALUE FUNCTION APPROACH AND HESSIAN-FREE ALGORITHM 12

CONSTRAINED BI-LEVEL OPTIMIZATION: PROXIMAL LAGRANGIAN VALUE...

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12th International Conference on Learning Representations, ICLR 2024

作者： Yao, Wei Yu, Chengming Zeng, Shangzhi Zhang, Jin National Center for Applied Mathematics Shenzhen SUSTech China Department of Mathematics SUSTech China Department of Mathematics and Statistics UVic Canada CETC Key Laboratory of Smart City Modeling Simulation and Intelligent Technology The Smart City Research Institute of CETC China

This paper presents a new approach and algorithm for solving a class of constrained Bi-Level Optimization (BLO) problems in which the lower-level problem involves constraints coupling both upper-level and lower-level variables. Such problems have recently gained significant attention due to their broad applicability in machine learning. However, conventional gradient-based methods unavoidably rely on computationally intensive calculations related to the Hessian matrix. To address this challenge, we devise a smooth proximal Lagrangian value function to handle the constrained lower-level problem. Utilizing this construct, we introduce a single-level reformulation for constrained BLOs that transforms the original BLO problem into an equivalent optimization problem with smooth constraints. Enabled by this reformulation, we develop a Hessian-free gradient-based algorithm-termed proximal Lagrangian Value function-based Hessian-free Bilevel Algorithm (LV-HBA)-that is straightforward to implement in a single loop manner. Consequently, LV-HBA is especially well-suited for machine learning applications. Furthermore, we offer non-asymptotic convergence analysis for LV-HBA, eliminating the need for traditional strong convexity assumptions for the lower-level problem while also being capable of accommodating non-singleton scenarios. Empirical results substantiate the algorithm's superior practical performance. © 2024 12th International Conference on Learning Representations, ICLR 2024. All rights reserved.

关键词： Machine learning

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Blockchain and PUF-based secure key establishment protocol for cross-domain digital twins in industrial Internet of Things architecture

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Journal of Advanced research 2024年 62卷 155-163页

作者： Mahmood, Khalid Shamshad, Salman Saleem, Muhammad Asad Kharel, Rupak Das, Ashok Kumar Shetty, Sachin Rodrigues, Joel J.P.C. School of Psychology and Computer Science University of Central Lancashire Preston United Kingdom Graduate School of Intelligent Data Science National Yunlin University of Science and Technology Yunlin 64002 Taiwan Department of Software Engineering The University of Lahore Lahore 54590 Pakistan Department of Computer Science University of Sahiwal Punjab Sahiwal 57000 Pakistan Center for Security Theory and Algorithmic Research International Institute of Information Technology Hyderabad 500 032 India Department of Modeling Simulation and Visualization Engineering Virginia Modeling Analysis and Simulation Center and Center for Cybersecurity Education and Research Old Dominion University Suffolk 23435 VA United States COPELABS Lusófona University Campo Grande 376 Lisbon 1749-024 Portugal

Introduction: The Industrial Internet of Things (IIoT) is a technology that connects devices to collect data and conduct in-depth analysis to provide value-added services to industries. The integration of the physical and digital domains is crucial for unlocking the full potential of the IIoT, and digital twins can facilitate this integration by providing a virtual representation of real-world entities. Objectives: By combining digital twins with the IIoT, industries can simulate, predict, and control physical behaviors, enabling them to achieve broader value and support industry 4.0 and 5.0. Constituents of cooperative IIoT domains tend to interact and collaborate during their complicated operations. Methods: To secure such interaction and collaborations, we introduce a blockchain-based cross-domain authentication protocol for IIoT. The blockchain maintains only each domain's dynamic accumulator, which accumulates crucial materials derived from devices, decreasing the overhead. In addition, we use the on-chain accumulator to effectively validate the unlinkable identities of cross-domain IIoT devices. Results: The implementation of the concept reveals the fact that our protocol is efficient and reliable. This efficiency and reliability of our protocol is also substantiated through comparison with state-of-the-art literature. In contrast to related protocols, our protocol exhibits a minimum 22.67% increase in computation cost efficiency and a 16.35% rise in communication cost efficiency. Conclusion: The developed protocol guarantees data transfer security across the domain and thwarts IoT devices from potential physical attacks. Additionally, in order to protect privacy, anonymity and unlinkability are also guaranteed. © 2024

关键词： Digital twins Industrial Internet of Things (IIoT) Key agreement Mutual authentication Physically Unclonable Functions (PUFs)

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Cross-sectional rainfall observation on the central-western Tibetan Plateau in the warm season:System design and preliminary results

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Science China Earth Sciences 2023年第5期66卷 1015-1030页

作者： Kun YANG Yingying CHEN Lazhu Changhui ZHAN Xiaoyan LING Xu ZHOU Yaozhi JIANG Xiangnan YAO Hui LU Xiaogang MA Lin OUYANG Weihao PAN Yanghang REN Changkun SHAO Jiaxin TIAN Yan WANG Hua YANG Siyu YUE Ke ZHANG Dingchi ZHAO Long ZHAO Jianhong ZHOU Mijun ZOU Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceInstitute for Global Change StudiesTsinghua UniversityBeijing100084China National Tibetan Plateau Data Center State Key Laboratory of Tibetan Plateau Earth System and Resource EnvironmentInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing100101China Research Center for Ecology College of ScienceTibet UniversityLhasa850011China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Science and Natural Resources ResearchChinese Academy of SciencesBeijing100101China Chongqing Jinfo Mountain Karst Ecosystem National Observation and Research Station School of Geographical SciencesSouthwest UniversityChongqing400715China

The central and western Tibetan Plateau(CWTP)is characterized by harsh environment and strong interactions among the spheres of earth as well as significant changes in climate and water cycles over the past four *** lack of precipitation observations is a bottleneck for the study of land surface processes in this *** the past six years,we have designed and established two observation transects across the south-north and the west-east in this region to obtain hourly rainfall data during the warm season(May-September).The south-north transect extends from Yadong Valley on the southern slope of the Himalayas to Shuanghu County in the hinterland of the plateau,with a total of 31stations;the west-east transect extends from Shiquanhe in the west to Naqu in the central TP,with a total of 22 *** observation dataset has been applied to clarify the spatiotemporal characteristics of precipitation in the CWTP,to evaluate the quality of typical gridded precipitation products,to support the development of regional climate models,and to reveal the processes of summertime lake-air *** observation dataset has been released in the national Tibetan Plateau Data center.

关键词： Central and western Tibetan Plateau Rainfall observation transects Observation uncertainty Spatiotemporal characteristics of precipitation Precipitation data evaluation

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Analysis of generalized compressor characteristics on surge phenomena in axial compressors

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Journal of Computational and Applied research in Mechanical Engineering 2021年第2期10卷 337-344页

作者： Maqsood, Adnan Tareen, Muhammad Kamran Khan Riaz, Rizwan Dala, Laurent Research Center for Modeling and Simulation National University of Sciences and Technology H–12 Campus Islamabad44000 Pakistan Department of Mechanical & Construction Engineering Northumbria University Newcastle United Kingdom

The paper discusses the effect of compressor characteristic on surge phenomena in axial flow compressors. Specifically, the effect of nonlinearities on the compressor dynamics is analyzed. For this purpose, generalized multiple time scales method is used to parameterize equations in amplitude and frequency explicitly. The pure surge case of the famous Moore-Greitzer model is used as the basis of the study. The compressor characteristic used in the Moore-Greitzer model is generalized to evaluate the effect of the parameters involved. Subsequently, bifurcation theory is used to study the effect of nonlinear dynamics on surge behavior. It has been found that the system exhibits supercritical Hopf bifurcation under specific conditions in which surge manifests as limit cycle oscillations. Key parameters have been identified in the analytical solution which govern the nonlinear dynamic behavior and are responsible for the existence of limit cycle oscillations. Numerical simulations of the Moore-Greitzer model are carried out and found to be in good agreement with the analytical solution. © 2021 The author(s).

关键词： Hopf bifurcation

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An Intelligent simulation Result Validation Method Based on Variational Autoencoder 23rd

An Intelligent Simulation Result Validation Method Based on ...

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23rd Asia simulation Conference, AsiaSim 2024

作者： Yang, Fan Ma, Ping Li, Wei Tao, Chao Yang, Ming Zhang, Jianchao Cheng, Huichuan Control and Simulation Center Harbin Institute of Technology Harbin150080 China National Key Laboratory of Complex System Modeling and Simulation Harbin150080 China Chinese Aeroengine Research Institute Beijing101304 China

ISBN: (纸本)9789819772247

Validation for complex system simulation faces the challenges of a large amount of validation data, which comes in the form of extensive samples and prolonged time series. To address this issue, this paper proposes an intelligent simulation result validation method based on Variational Autoencoder (VAE), achieving model validation through intelligent feature extraction and feature consistency metrics. Initially, we present the overall validation framework, which consists of feature extraction and simulation result validation, and detail the steps of the validation process. Subsequently, the principles and procedures of the feature extraction and simulation result validation methods are thoroughly discussed. The feature extraction is achieved by learning the distribution parameters of the latent space using a VAE model. Feature differences across various aspects are measured by three distance metrics and are further converted into simulation credibility. Finally, the effectiveness and superiority of this method are demonstrated through a case study on validating a drone delivery model. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Digital elevation model

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Composability Verification of Complex Systems Using Colored Petri Nets

Composability Verification of Complex Systems Using Colored ...

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2021 Winter simulation Conference, WSC 2021

作者： Mahmood, Imran Askari, Syed Hassan Sarjoughian, Hessam S. Center for Research in Modeling Simulation School of Electrical Engineering and Computer Science National University of Sciences and Technology Islamabad Pakistan

ISBN: (纸本)9781665433112

The discipline of component-based modeling and simulation offers promising gains including reductions in development cost, time, and system complexity. This paradigm promotes the use and reuse of modular components for adequate development of complex simulations. Achieving effective and meaningful model reuse through the composition of components still remains a daunting challenge. 'Composability', an integral part of this challenge, is the capability to select and assemble model components in various combinations to satisfy specific user requirements. In this paper, we propose the use of Colored Petri Nets for component-oriented model development, model composition, and the verification of composed models using state-space analysis technique. We present a case study of an elevator model as a proof of concept. Our case study explains the proposed process of developing and composing CPN-based model components and verifying the composed model using state-space analysis. © 2021 IEEE.

关键词： Petri nets

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