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International Conference on Information and Communication Technology Convergence (ICTC)

作者： Taehan Moon Heonwoo Chu Wonjae Lee Jae-Hyun Kim Department of Artificial Intelligence Convergence Network Ajou University Suwon South Korea Department of Electrical and Computer Engineering Ajou University Suwon South Korea

ISBN: (数字)9798350364637

ISBN: (纸本)9798350364644

Low Earth Orbit (LEO) satellites offer significant advantages in terms of extensive coverage and service connectivity. Many researchers are currently focusing on commercial LEO constellations, such as SpaceX and One Web. In particular, Signal-to-Noise Ratio (SNR) and Line-of-Sight (LoS) are crucial for ensuring high-quality service in LEO satellite communications. In this paper, we evaluate a detailed analysis of the SNR and LoS performance between SpaceX and OneWeb. The simulation results show that the LEO satellites satisfy the minimum technical performance requirements in the South Korea region.

关键词： Satellite constellations Satellites Simulation Low earth orbit satellites Line-of-sight propagation Interference Performance analysis Reliability Satellite communications Signal to noise ratio

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Performance Evaluation of Distance-Based Handover Using LSTM in LEO-Based NTN

Performance Evaluation of Distance-Based Handover Using LSTM...

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International Conference on Information and Communication Technology Convergence (ICTC)

作者： Yujeong Ahn Jongtae Lee Tae-Yoon Kim Jae-Hyun Kim Department of Artificial Intelligence Convergence Network Ajou University Suwon South Korea Department of Electrical and Computer Engineering Ajou University Suwon South Korea

ISBN: (数字)9798350364637

ISBN: (纸本)9798350364644

In terrestrial networks (TN), the user equipment (UE) identifies the cell edge by detecting differences in reference signal received power (RSRP). However, in non-terestrial networks (NTN), these effects are minimal due to the high altitude, and frequent handover (HO) may occur. For address this issue, the 3rd Generation Partnership Project (3GPP) Release-17 introduced novel HO triggering conditions, such as distance-based and time(r)-based HO [1]. Especially, distance-based HO addresses the challenge of minimal RSRP differences in cell overlapping areas. However, it is performed based on distance without considering RSRP, which can present challenges in maintaining the average RSRP of the UE. Therefore, a method is necessary to determine the optimal distance-based offset that can maintain RSRP for the UE. In this paper, we propose a distance-based HO using long short-term memory (LSTM) to predict the average signal-to-interference-plus-noise-ratio (SINR), identify the optimal HO triggering position, and determine the distance-based HO triggering offset. Performance analysis demonstrates that the proposed distance-based HO maintains the average SINR while significantly reducing unnecessary HO compared to the RSRP-based HO.

关键词： Performance evaluation Interference Handover Stability analysis Trajectory Performance analysis 3GPP Long short term memory Thermal stability Signal to noise ratio

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A Channel Estimation Method for Modified Walsh-Hadamard Code Division Multiplexing in Helicopter Satellite Communications and Its Application to Initial Acquisition

A Channel Estimation Method for Modified Walsh-Hadamard Code...

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International Conference on Advanced Technologies for Communications, ATC

作者： Yuto Yoshinaka Toshiharu Kojima Department of Computer and Network Engineering Graduate School of Informatics and Engineering The University of Electro-Communications1-5-1 Chofugaoka Chofu Tokyo Japan

Modified Walsh-Hadamard code division multiplexing (MWHCDM) is a promising solution for the degradation of bit error rate (BER) performance due to the periodic blockage (PB) of the channel caused by rotor blades in helicopter satellite communications. While zero-forcing (ZF) enhances the anti-PB capability of MWHCDM, it requires channel information. This paper proposes a channel estimation method for MWHCDM, discussing its application to initial acquisition. The proposed channel estimation method reproduces the transmitted signal from the received signal by utilizing the structure of MWHCDM signals. It estimates the channel information based on the cross-correlation coefficient between the reproduced transmitted signal and the received signal. computer simulation shows that introducing ZF combined with the proposed channel estimation method to initial acquisition significantly improves the acquisition performance in the PB channel, similar to the BER performance.

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Computing Minimal Absent Words and Extended Bispecial Factors with CDAWG Space

arXiv

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arXiv 2024年

作者： Inenaga, Shunsuke Mieno, Takuya Arimura, Hiroki Funakoshi, Mitsuru Fujishige, Yuta Department of Informatics Kyushu University Japan Department of Computer and Network Engineering University of Electro-Communications Japan Graduate School of IST Hokkaido University Japan

A string w is said to be a minimal absent word (MAW) for a string S if w does not occur in S and any proper substring of w occurs in S. We focus on non-trivial MAWs which are of length at least 2. Finding such non-trivial MAWs for a given string is motivated by applications in bioinformatics and data compression. Fujishige et al. [TCS 2023] proposed a data structure of size Θ(n) that can output the set MAW(S) of all MAWs for a given string S of length n in O(n + |MAW(S)|) time, based on the directed acyclic word graph (DAWG). In this paper, we present a more space efficient data structure based on the compact DAWG (CDAWG), which can output MAW(S) in O(|MAW(S)|) time with O(emin) space, where emin denotes the minimum of the sizes of the CDAWGs for S and for its reversal SR. For any strings of length n, it holds that emin min can be sublinear (up to logarithmic) in n. We also show that MAWs and their generalization minimal rare words have close relationships with extended bispecial factors, via the CDAWG. Copyright © 2024, The Authors. All rights reserved.

关键词： Data structures

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Analysis of LEO Satellite network Performace according to Phasing Factor: Polar Region Boundary, Minimun Elevation angle

Analysis of LEO Satellite Network Performace according to Ph...

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International Conference on Ubiquitous and Future networks, ICUFN

作者： Heon-Woo Chu Tae-Yoon Kim Jae-Hyun Kim Department of Artificial Intelligence Convergence Network Ajou University Suwon South Korea Department of Electrical and Computer Engineering Ajou University Suwon South Korea

ISBN: (数字)9798350385298

ISBN: (纸本)9798350385304

The deployment model of low-Earth orbit (LEO) satellites astonishingly affects LEO satellite network performance. The deployment of satellites generates a polar region that reduces communication performance. Due to the relative velocity between satellites, inter satellite link is impossible in the polar region. The relative velocity between satellites is caused by the phase offset defined by the phasing factor. Therefore, since the polar region is affected by the phasing factor, it should be considered in the satellite network design. In this paper, we analyze the polar region boundary and minimum elevation angle of the LEO satellite network according to the phasing factor. The analysis of the polar region is demonstrated considering the Iridium and OneWeb LEO satellite constellations. Simulation results show that the polar region boundary differs by up to 19 degrees, and the minimum elevation angle of the ground station differs by up to 2.8 degrees depending on the phasing factor.

关键词： Satellite constellations Satellites Simulation Low earth orbit satellites Orbits Iridium

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Receptor model-based sources and risks appraisal of potentially toxic elements in the urban soils of Bangladesh

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Toxicology Reports 2023年 10卷 308-319页

作者： Chakraborty, Tapos Kumar Islam, Md Shahnul Ghosh, Gopal Chandra Ghosh, Prianka Zaman, Samina Hossain, Md Ripon Habib, Ahsan Nice, Md Simoon Rahman, Md Sozibur Islam, Khandakar Rashedul Netema, Baytune Nahar Das Shuvo, Suvasish Hossain, Nazmul Khan, Abu Shamim Department of Environmental Science and Technology Jashore University of Science and Technology Jashore 7408 Bangladesh Department of Nutrition and Food Technology Jashore University of Science and Technology Jashore 7408 Bangladesh Department of Computer Science and Engineering Jashore University of Science and Technology Jashore 7408 Bangladesh Environmental Laboratory Asia Arsenic Network Jashore 7400 Bangladesh

Rapid urbanization and industrial development have prompted potentially toxic elements (PTEs) in urban soil in Bangladesh, which is a great concern for ecological and public health matters. The present study explored the receptor-based sources, probable human health and ecological risks of PTEs (As, Cd, Pb, Cr, Ni, and Cu) in the urban soil of the Jashore district, Bangladesh. The USEPA modified method 3050B and atomic absorption spectrophotometers were used to digest and evaluate the PTEs concentration in 71 soil samples collected from eleven different land use areas, respectively. The concentration ranges of As, Cd, Pb, Cr, Ni, and Cu in the studied soils were 1.8—18.09, 0.1—3.58, 0.4—113.26, 0.9—72.09, 2.1—68.23, and 3.82—212.57 mg/kg, respectively. The contamination factor (CF), pollution load index (PLI), and enrichment factor (EF) were applied to evaluate the ecological risk posed by PTEs in soils. Soil quality evaluation indices showed that Cd was a great contributor to soil pollution. The PLI values range was 0.48–2.82, indicating base levels to continuous soil degradation. The positive matrix factorization (PMF) model showed that As (50.3 %), Cd (38.8 %), Cu (64.7 %), Pb (81.8 %) and Ni (47.2 %) were derived from industrial sources and mixed anthropogenic sources, while Cr (78.1 %) from natural sources. The highest contamination was found in the metal workshop, followed by the industrial area, and brick filed site. Soil from all land use types revealed moderate to high ecological risk after evaluating probable ecological risks, and the descending order of single metal potential ecological risk was Cd > As > Pb > Cu > Ni > Cr. Ingestion was the primary route of exposure to potentially toxic elements for both adults and children from the study area soil. The overall non-cancer risk to human health is caused by PTEs for children (HI=0.65 ± 0.1) and adults (HI=0.09 ± 0.03) under USEPA safe limit (HI>1), while the cancer risks from exclusively ingesting As throu

关键词： Bangladesh Ecological risk Hazardous elements Public health Urban land use

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Robust restoration of low-dose cerebral perfusion CT images using NCS-Unet

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Nuclear Science and Techniques 2022年第3期33卷 62-76页

作者： Kai Chen Li-Bo Zhang Jia-Shun Liu Yuan Gao Zhan Wu Hai-Chen Zhu Chang-Ping Du Xiao-Li Mai Chun-Feng Yang Yang Chen Southeast University Nanjing 210096China School of Cyber Science and Engineering Southeast UniversityNanjing 210096China Key Laboratory of Computer Network and Information Integration(Southeast University) Ministry of EducationNanjing 210096China Department of Radiology General Hospital of the Northern Theater of the Chinese People’s Liberation ArmyShenyang 110016China Laboratory of Image Science and Technology The School of Computer Science and EngineeringSoutheast UniversityNanjing 210096China Department of Radiology Nanjing Drum Tower HospitalThe Affiliated Hospital of Nanjing University Medical SchoolNanjing 210008China Jiangsu Key Laboratory of Molecular and Functional Imaging Department of RadiologyZhongda HospitalSoutheast UniversityNanjing 210009China Jiangsu Provincial Joint International Research Laboratory of Medical Information Processing School of Computer Science and EngineeringSoutheast UniversityNanjing 210096China

Cerebral perfusion computed tomography(PCT)is an important imaging modality for evaluating cerebrovascular diseases and stroke *** widespread public concern about the potential cancer risks and health hazards associated with cumulative radiation exposure in PCT imaging,considerable research has been conducted to reduce the radiation dose in X-ray-based brain perfusion *** the dose of X-rays causes severe noise and artifacts in PCT *** solve this problem,we propose a deep learning method called *** exceptional characteristics of non-subsampled contourlet transform(NSCT)and the Sobel filter are introduced into *** decomposes the convolved features into high-and low-frequency *** decomposed high-frequency component retains image edges,contrast imaging traces,and noise,whereas the low-frequency component retains the main image *** Sobel filter extracts the contours of the original image and the imaging traces caused by the contrast agent *** extracted information is added to NCS-Unet to improve its performance in noise reduction and artifact *** and quantitative analyses demonstrated that the proposed NCS-Unet can improve the quality of low-dose cone-beam CT perfusion reconstruction images and the accuracy of perfusion parameter calculations.

关键词： Cerebral perfusion CT Low-dose Image denoising Perfusion parameters

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NetHCF: Filtering Spoofed IP Traffic With Programmable Switches

NetHCF: Filtering Spoofed IP Traffic With Programmable Switc...

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作者： Zhang, Menghao Li, Guanyu Kong, Xiao Liu, Chang Xu, Mingwei Gu, Guofei Wu, Jianping Tsinghua University Institute for Network Sciences and Cyberspace Beijing100084 China Kuaishou Technology Beijing100085 China Tsinghua University Department of Computer Science and Technology Beijing100084 China Beijing100084 China Texas A&m University Department of Computer Science and Engineering College StationTX77840 United States

In this paper, we identify the opportunity of using programmable switches to improve the state of the art in spoofed IP traffic filtering, and propose NetHCF, a line-rate in-network system to filter spoofed traffic. One key challenge in the design of NetHCF is to handle the restrictions stemmed from the limited computational model and memory resources of programmable switches. We address this by decomposing the HCF scheme into two complementary parts, by aggregating the IP-to-Hop-Count (IP2HC) mapping table for efficient memory usage, and by designing adaptive mechanisms to handle routing changes, IP popularity changes, and network activity dynamics. We implement an open-source prototype of NetHCF, and conduct extensive evaluations. The evaluation results demonstrate that NetHCF is able to process most legitimate traffic in 1 $\mu$μs, filter spoofed IP traffic effectively under network dynamics, with less than 30% of switch resource occupation. © 2004-2012 IEEE.

关键词： Timing circuits

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Fast Mesh Reconstruction from Single View Based on GCN and Topology Modification

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computer Systems Science & engineering 2023年第5期45卷 1695-1709页

作者： Xiaorui Zhang Feng Xu Wei Sun Yan Jiang Yi Cao Wuxi Research Institute Nanjing University of Information Science&TechnologyWuxi214100China Engineering Research Center of Digital Forensics Ministry of EducationJiangsu Engineering Center of Network MonitoringSchool of Computer and SoftwareNanjing University of Information Science&TechnologyNanjing210044China Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET) Nanjing University of Information Science&TechnologyNanjing210044China School of Automation Nanjing University of Information Science&TechnologyNanjing210044China Department of Electrical and Computer Engineering University of WindsorWindsorONN9B 3P4Canada

3D reconstruction based on single view aims to reconstruct the entire 3D shape of an object from one *** existing methods reconstruct the mesh surface of complex objects,the surface details are difficult to predict and the reconstruction visual effect is poor because the mesh representation is not easily integrated into the deep learning framework;the 3D topology is easily limited by predefined templates and inflexible,and unnecessary mesh self-intersections and connections will be generated when reconstructing complex topology,thus destroying the surface details;the training of the reconstruction network is limited by the large amount of information attached to the mesh vertices,and the training time of the reconstructed network is too *** this paper,we propose a method for fast mesh reconstruction from single view based on Graph Convolutional network(GCN)and topology *** use GCN to ensure the generation of high-quality mesh surfaces and use topology modification to improve the flexibility of the ***,a feature fusion method is proposed to make full use of the features of each stage of the image *** use 3D open dataset ShapeNet to train our network and add a new weight parameter to speed up the training *** experiments demonstrate that our method can not only reconstruct object meshes on complex topological surfaces,but also has better qualitative and quantitative results.

关键词： 3D surface reconstruction deep learning GCN topology modification end-to-end framework

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Adaptive Defense Mechanisms Against Zero-Day Attacks in Wireless Sensor networks

Adaptive Defense Mechanisms Against Zero-Day Attacks in Wire...

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Distributed Systems, computer networks and Cybersecurity (ICDSCNC), International Conference on

作者： Abhay Chaturvedi Sanjeev Kukreti Durga Bhavani A Venkata Naga Ravi Kiran Nizampatnam Davinder Kaur Natrayan L Department of Electronics & Communication Engineering GLA University Chaumuhan India Department of Computer Science & Engineering Graphic Era Deemed to be University Dehradun India Department of Computer Science and Engineering BMS Institute of Technology and Management Bengaluru India Department of Computer Networks Expert Network Security Engineer Acxiom LLC Austin Texas USA Department of Law Symbiosis Law School Symbiosis International (Deemed University) Pune India Department of Mechanical Engineering Saveetha School of Engineering SIMATS Kuthambakkam India

ISBN: (数字)9798350375442

ISBN: (纸本)9798350375459

Important fields including healthcare, environmental monitoring, and military operations are seeing a rise in the use of wireless sensor networks (WSNs). But they are susceptible to complex cyber dangers, especially zero-day assaults, due to their dispersed nature and lack of resources. In order to protect WSNs against zero-day attacks, this research introduces an Adaptive Defense Mechanism (ADM). A dynamic response system that can adjust to changing attack patterns in real-time is integrated with machine learning-based anomaly detection in the proposed ADM. A hybrid model integrating Support Vector Machines (SVM) and Long Short-Term Memory (LSTM) networks is used by the anomaly detection module. It achieves a detection accuracy of 94.7% on simulated zero-day assault scenarios. In comparison to static defensive systems, the ADM's adaptive response mechanism, which is based on reinforcement learning, dynamically modifies the network's security regulations, resulting in a 23.5% reduction in false positives. Results from testing the proposed ADM in a simulated WSN setting show that it can greatly improve the network's ability to withstand zero-day assaults. With assaults present, the total network throughput increased by 15% and the average detection time dropped to 0.35 seconds. Based on these findings, the ADM provides a strong and effective defensive technique, guaranteeing the safety and dependability of WSNs in mission-critical applications.

关键词： Support vector machines Wireless sensor networks Adaptive systems Reinforcement learning Throughput Routing protocols computer security Long short term memory Anomaly detection Testing

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