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Joint Optimization of UAV Placement and Resource Allocation in FDMA Wireless-Powered Sensor Networks

IEEE Access 2025年 13卷 92873-92881页

作者： Ghasemi, Omid Abachian Chehel Amirani, Mehdi Urmia University Department of Electrical and Computer Engineering Urmia57561-51818 Iran

This paper investigates uncrewed aerial vehicle (UAV)-assisted wireless powered sensor networks (WPSNs). In this system, sensors harvest energy radiated from a UAV and use this energy to transmit collected data back to the UAV via frequency division multiple access (FDMA). The objective is to maximize the sum-throughput, subject to constraints on transmission scheduling and bandwidth allocation, while guaranteeing a minimum throughput for each sensor. This problem is non-convex due to the presence of coupled variables. To solve it, the alternating minimization technique is used, where the problem is divided into subproblems with respect to each of the variables by fixing the others. Efficient algorithms based on the dual Lagrange method and Karush-Kuhn-Tucker (KKT) conditions are proposed for optimal transmission time scheduling and bandwidth allocation. These algorithms offer significant advantages in execution time. The UAV placement subproblem is addressed using successive convex approximation (SCA), which iteratively maximizes a lower bound. Numerical results clearly show that the proposed method outperforms the benchmarks and has a much lower execution time compared to its time division multiple access (TDMA) counterpart. © 2013 IEEE.

关键词： Drones

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Performance and evaluation of OTFS modulation systems using different high mobility channels

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International Journal of Electronics and Telecommunications 2025年第2期71卷 505-512页

作者： Khadum, Sura H. Jamel, Thamer M. Kkhazaal, Hassan F. Department of Communications Engineering University of Technology Baghdad Iraq Department of Electrical Engineering Wasit University Wasit Iraq

This research examines how Nextgen wireless systems can benefit from Orthogonal Time Frequency Space (OTFS) modulation in different high-mobility channel situations. We test the BER performance of OTFS and OFDM with varying lengths of symbol under varied transmit power (TX power) conditions utilizing simulations employing Doubly-Selective, Extended Vehicular A (EVA), Unmanned Aerial Vehicle (UAV), and Extended Typical Urban (ETU) channel models. Compared to OFDM, OTFS reliably reduces the impact of multipath propagation and Doppler spread more effectively. Importantly, to maximize BER performance in UAV channel simulations, the OTFS symbol length had to be carefully selected;increasing the symbol length without thinking about it led to decreasing results. It was shown that OTFS is connected to a few resources in the ETU channel due to its minimal demand on TX Power. Based on these results, OTFS seems to be a good modulation technique for demanding mobile communication applications, particularly for UAV communications where picking the right parameters is key. Methods for adaptive OTFS that can change symbol length and other parameters in reaction to channel circumstances in real-time should be the focus of future studies. © The Author(s).

关键词： Drones

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Secure beamforming and deployment design for rate-splitting multiple access-based UAV communications

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Science China(Information Sciences) 2025年第1期68卷 342-356页

作者： Bing WANG Xiaofeng TAO Shujun HAN Huici WU Kai YANG Zhu HAN National Engineering Research Center of Mobile Network Technologies Beijing University of Posts and Telecommunications Peng Cheng Laboratory Department of Electrical and Computer Engineering University of Houston

Rate-splitting multiple access(RSMA) has recently gained attention as a potential robust multiple access(MA)scheme for upcoming wireless networks. Given its ability to efficiently utilize wireless resources and design interference management strategies, it can be applied to unmanned aerial vehicle(UAV) networks to provide convenient services for large-scale access ground users. However, due to the line-of-sight(LoS) broadcast nature of UAV transmission, information is susceptible to eavesdropping in RSMA-based UAV networks. Moreover, the superposition of signals at the receiver in such networks becomes complicated. To cope with the challenge, we propose a two-user multi-input single-output(MISO) RSMA-based UAV secure transmission framework in downlink communication networks. In a passive eavesdropping scenario, our goal is to maximize the sum secrecy rate by optimizing the transmit beamforming and deployment location of the UAV-base station(UAV-BS),while considering quality-of-service(QoS) constraints, maximum transmit power, and flight space limitations. To address the non-convexity of the proposed problem, the optimization problem is first decoupled into two subproblems. Then, the successive convex approximation(SCA) method is employed to solve each subproblem using different propositions. In addition, an alternating optimization(AO)-based location RSMA(L-RSMA) beamforming algorithm is developed to implement joint optimization to obtain the suboptimal solution. Numerical results demonstrate that(1) the proposed L-RSMA scheme yields a28.97% higher sum secrecy rate than the baseline L-space division multiple access(SDMA) scheme;(2) the proposed L-RSMA scheme improves the security performance by 42.61% compared to the L-non-orthogonal multiple access(NOMA) scheme.

关键词： rate-splitting multiple access UAV communication precoding optimization deployment location physical layer security

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THEMIS: Time, Heterogeneity, and Energy Minded Scheduling for Fair Multi-Tenant Use in FPGAs

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IEEE Transactions on computers 2025年第7期74卷 2515-2528页

作者： Karabulut, Emre Malik, Arsalan Ali Awad, Amro Aysu, Aydin University of Oxford Department of Electrical Engineering United Kingdom North Carolina State University Department of Electrical and Computer Engineering RaleighNC27606 United States

Using correct design metrics and understanding the limitations of the underlying technology is critical to developing effective scheduling algorithms. Unfortunately, existing scheduling techniques used incorrect metrics and had un-realistic assumptions for fair scheduling of multi-tenant FPGAs where each tenant is aimed to share approximately the same number of resources both spatially (in space) and temporally (in time). This paper proposes an improved fair scheduling algorithm that fixes earlier issues with metrics and assumptions for ‘fair’ multi-tenant FPGA use. Specifically, we claim three improvements. First, we consider both spatial and temporal aspects to provide spatiotemporal fairness—this improves a recent prior work that assumed all tasks would have the same latency. Second, we add the energy dimension to fairness: by calibrating the scheduling decision intervals and including their energy overhead, our algorithm offers trading off energy efficiency for fairness. Third, we consider previously ignored facts about FPGA multi-tenancy, such as the existence of heterogeneous regions and the inflexibility of run-time merging/splitting of partially reconfigurable *** develop and evaluate our improved fair scheduling algorithm with these three enhancements. Inspired by the Greek goddess of law and personification of justice, we name our fair scheduling solution THEMIS: Time, Heterogeneity, and Energy Minded Scheduling. We implemented our solution on Xilinx Zedboard XC7Z020 with real hardware workloads and used real measurements on the FPGA to quantify the savings of our approach. Compared to previous algorithms, our improved scheduling algorithm enhances fairness between 24.2–98.4% and allows a trade-off between 55.3× in energy vs. 69.3× in fairness. The paper thus informs cloud providers about future scheduling optimizations for fairness with related challenges and opportunities. © 1968-2012 IEEE.

关键词： Scheduling algorithms

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Scheduling Policies in a Multi-Source Status Update System with Dedicated and Shared Servers

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IEEE Internet of Things Journal 2025年第13期12卷 22772-22785页

作者： Liyanaarachchi, Sahan Ulukus, Sennur Akar, Nail University of Maryland Department of Electrical and Computer Engineering College ParkMD20742 United States Bilkent University Electrical and Electronics Engineering Department Ankara Turkey

Use of multi-path network topologies has become a prominent technique to assert timeliness in terms of age of information (AoI) and to improve resilience to link disruptions in communication systems. However, establishing multiple dedicated communication links among network nodes is a costly endeavor. Therefore, quite often, these secondary communication links are shared among multiple entities. Moreover, these multi-path networks come with the added challenge of out-of-order transmissions. In this paper, we study an amalgamation of the above two aspects, i.e., multi-path transmissions and link sharing. In contrast to the existing literature where the main focus has been scheduling multiple sources on a single shared server, we delve into the realm where each source sharing the shared server is also supplemented with its dedicated server so as to improve its timeliness. In this multi-path link sharing setting with generate-at-will transmissions, we first present the optimal probabilistic scheduler, and then propose several heuristic-based cyclic scheduling algorithms for the shared server, to minimize the weighted average age of information of the sources. © 2014 IEEE.

关键词： Servers Probabilistic logic Optimal scheduling Out of order Queueing analysis Relay networks Moon Monitoring Job shop scheduling Information age

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III-nitride nanostructures: Selective area epitaxy, surface emitting lasers, and emerging photodetectors

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Semiconductors and Semimetals 2024年 116卷 1-23页

作者： Zhao, Songrui Department of Electrical and Computer Engineering McGill University MontrealQC Canada

ISBN: (纸本)9780443296888

III-nitride nanowires have emerged as an important semiconductor device technology development platform, leveraging the unique physical properties of III-nitride semiconductors such as widely tunable bandgap energies, as well as the merits of semiconductor nanowires such as the large surface area to the bulk volume ratio. The past ten years have witnessed a lot of exciting developments on III-nitride nanowire photonic devices. With limited text, the intention of this book chapter is to describe some of the key advances related to the III-nitride nanowire epitaxy, lasers, and photodetectors in the past few years. The prospect of III-nitride nanowire photonic devices in the next decade and beyond is also discussed, and they are expected to be the game changers for various applications such as display, imaging, and information processing, to just name a few. © 2024

关键词： Photonic devices

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United We Fall: On the Nash Equilibria of Multiplex and Multilayer Network Games

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IEEE Transactions on Control of Network Systems 2025年第2期12卷 1238-1250页

作者： Ebrahimi, Raman Naghizadeh, Parinaz University of California Electrical and Computer Engineering Department San Diego United States

Network games provide a framework to study strategic decision making processes that are governed by structured interdependencies among agents. However, existing models do not account for environments in which agents simultaneously interact over multiple networks, or when agents operate over multiple action dimensions. In this paper, we propose new models of multiplex network games to capture the different modalities of interactions among strategic agents, and multilayer network games to capture their interactions over multiple action dimensions. We explore how the properties of the constituent networks of a multiplex/multilayer network can undermine or support the existence, uniqueness, and stability of the game's Nash equilibria. Notably, we highlight that both the largest and smallest eigenvalues of the constituent networks (reflecting their connectivity and two-sidedness, respectively) are instrumental in determining the uniqueness of the multiplex/multilayer network game's equilibrium. Together, our findings shed light on the reasons for the fragility of equilibria when agents interact over networks of networks, and point out potential interventions to alleviate them. © 2014 IEEE.

关键词： Nash equilibrium

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Universal Joint Source-Channel Coding for Modulation-Agnostic Semantic Communication

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IEEE Journal on Selected Areas in Communications 2025年第7期43卷 2560-2574页

作者： Huh, Yoon Seo, Hyowoon Choi, Wan Departement of Electrical and Computer Engineering Institute of New Media and Communications Seoul08826 Korea Republic of Sungkyunkwan University Department of Electrical and Computer Engineering Suwon16419 Korea Republic of

From the perspective of joint source-channel coding (JSCC), there has been significant research on utilizing semantic communication, which inherently possesses analog characteristics, within digital device environments. However, a single-model approach that operates modulation-agnostically across various digital modulation orders has not yet been established. This article presents the first attempt at such an approach by proposing a universal joint source-channel coding (uJSCC) system that utilizes a single-model encoder-decoder pair and trained vector quantization (VQ) codebooks. To support various modulation orders within a single model, the operation of every neural network (NN)-based module in the uJSCC system requires the selection of modulation orders according to signal-to-noise ratio (SNR) boundaries. To address the challenge of unequal output statistics from shared parameters across NN layers, we integrate multiple batch normalization (BN) layers, selected based on modulation order, after each NN layer. This integration occurs with minimal impact on the overall model size. Through a comprehensive series of experiments, we validate that the modulation-agnostic semantic communication framework demonstrates superiority over existing digital semantic communication approaches in terms of model complexity, communication efficiency, and task effectiveness. © 1983-2012 IEEE.

关键词： Vector quantization

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COVID-19 emergency decision-making using q-rung linear diophantine fuzzy set,differential evolutionary and evidential reasoning techniques

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Applied Mathematics(A Journal of Chinese Universities) 2025年第1期40卷 182-206页

作者： G Punnam Chander Sujit Das Department of Computer science and Engineering National Institute of TechnologyWarangal 506004India

In this paper,a robust and consistent COVID-19 emergency decision-making approach is proposed based on q-rung linear diophantine fuzzy set(q-RLDFS),differential evolutionary(DE)optimization principles,and evidential reasoning(ER)*** proposed approach uses q-RLDFS in order to represent the evaluating values of the alternatives corresponding to the *** optimization is used to obtain the optimal weights of the attributes,and ER methodology is used to compute the aggregated q-rung linear diophantine fuzzy values(q-RLDFVs)of each *** the score values of alternatives are computed based on the aggregated *** alternative with the maximum score value is selected as a better *** applicability of the proposed approach has been illustrated in COVID-19 emergency decision-making system and sustainable energy planning ***,we have validated the proposed approach with a numerical ***,a comparative study is provided with the existing models,where the proposed approach is found to be robust to perform better and consistent in uncertain environments.

关键词： COVID-19 q-rung linear diophantine fuzzy set differential evolutionary evidential reasoning decision-making

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AICSD: Adaptive inter-class similarity distillation for semantic segmentation

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Multimedia Tools and Applications 2025年 1-20页

作者： Mansourian, Amir M. Ahamdi, Rozhan Kasaei, Shohreh Department of Computer Engineering Sharif University of Technology Tehran Iran

In recent years, deep neural networks have achieved remarkable accuracy in computer vision tasks. With inference time being a crucial factor, particularly in dense prediction tasks such as semantic segmentation, knowledge distillation has emerged as a successful technique for improving the accuracy of lightweight student networks. The existing methods often neglect the information in channels and among different classes. To overcome these limitations, this paper proposes a novel method called Inter-Class Similarity Distillation (ICSD) for the purpose of knowledge distillation. The proposed method transfers high-order relations from the teacher network to the student network by independently computing intra-class distributions for each class from network outputs. This is followed by calculating inter-class similarity matrices for distillation using KL divergence between distributions of each pair of classes. To further improve the effectiveness of the proposed method, an Adaptive Loss Weighting (ALW) training strategy is proposed. Unlike existing methods, the ALW strategy gradually reduces the influence of the teacher network towards the end of the training process to account for errors in teacher’s predictions. Extensive experiments conducted on two well-known datasets for semantic segmentation, Cityscapes, Pascal VOC 2012, and COCO, validate the effectiveness of the proposed method in terms of mIoU and pixel accuracy. The proposed method outperforms most of existing knowledge distillation methods as demonstrated by both quantitative and qualitative evaluations. Code is available at: https://***/AmirMansurian/AICSD © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.

关键词： Semantic Segmentation

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