results: 研究在模拟 urbana 环境中进行了实验，并结果表明，通过使用计算机视觉技术可以增强探测敏感度和场景认知。Abstract
The addition of contextual sensors to mobile radiation sensors provides valuable information about radiological source encounters that can assist in adjudication of alarms. This study explores how computer-vision based object detection and tracking analyses can be used to augment radiological data from a mobile detector system. We study how contextual information (streaming video and LiDAR) can be used to associate dynamic pedestrians or vehicles with radiological alarms to enhance both situational awareness and detection sensitivity. Possible source encounters were staged in a mock urban environment where participants included pedestrians and vehicles moving in the vicinity of an intersection. Data was collected with a vehicle equipped with 6 NaI(Tl) 2 inch times 4 inch times 16 inch detectors in a hexagonal arrangement and multiple cameras, LiDARs, and an IMU. Physics-based models that describe the expected count rates from tracked objects are used to correlate vehicle and/or pedestrian trajectories to measured count-rate data through the use of Poisson maximum likelihood estimation and to discern between source-carrying and non-source-carrying objects. In this work, we demonstrate the capabilities of our source-object attribution approach as applied to a mobile detection system in the presence of moving sources to improve both detection sensitivity and situational awareness in a mock urban environment.
摘要
通过添加上下文感知器到移动辐射检测器，可以获得辐射源遇到的有价值信息，以帮助解决警报。本研究探讨了如何使用计算机视觉基于对象检测和跟踪分析来增强移动检测系统中的辐射数据。我们研究了如何使用上下文信息（流动视频和LiDAR）将动态行人或车辆与辐射警报相关联，以提高 situational awareness 和检测敏感度。在模拟城市环境中，参与者包括行人和车辆在交叉口附近移动。数据收集使用装备了6个 NaI(Tl) 2英寸×4英寸×16英寸检测器的车辆，以及多个摄像头、LiDAR和IMU。我们使用物理学基于的模型来 correlate 跟踪物体的轨迹和测量的计数率数据，并使用波利奥最大 likelihood 估计来准确归类源包含和不包含源的物体。在这种情况下，我们展示了我们的源-物体归类方法在移动检测系统中的应用，以提高检测敏感度和 situational awareness 在模拟城市环境中。
Bayesian topology inference on partially known networks from input-output pairs
results: 通过对实际和Synthetic网络的数据进行数值实验， authors 示出了 integrating prior knowledge 可以提高估计性能。Abstract
We propose a sampling algorithm to perform system identification from a set of input-output graph signal pairs. The dynamics of the systems we study are given by a partially known adjacency matrix and a generic parametric graph filter of unknown parameters. The methodology we employ is built upon the principles of annealed Langevin diffusion. This enables us to draw samples from the posterior distribution instead of following the classical approach of point estimation using maximum likelihood. We investigate how to harness the prior information inherent in a dataset of graphs of different sizes through the utilization of graph neural networks. We demonstrate, via numerical experiments involving both real-world and synthetic networks, that integrating prior knowledge into the estimation process enhances estimation performance.
摘要
我们提出一种采样算法来进行系统识别从输入-输出图信号对的集合。我们研究的系统动力是由一个部分知道的邻接矩阵和一个通用参数图 filter 的未知参数给出的。我们使用渐进的兰格易托 diffusion 的原则来实现采样，这使得我们可以从 posterior 分布中采样而不是使用传统的点估计方法。我们研究如何在不同大小的图 dataset 中利用图神经网络来加持先验知识。我们通过实验表明，通过将先验知识 integrate 到估计过程中，可以提高估计性能。Note that the translation is in Simplified Chinese, which is the standard writing system used in mainland China. If you prefer Traditional Chinese, I can provide that as well.
Design and Implementation of DC-to-5~MHz Wide-Bandwidth High-Power High-Fidelity Converter
results: 我们开发了一个轻量级嵌入式控制解决方案，包括改进的静止表示数字synthesizer和一种新的适应偏好束拟合 nearest-level 模ulation。这种解决方案可以有效解决高功率和高输出频率之间的冲突，并且可以在两个维度上扩展。我们的原型在DC至5MHz的频谱范围内，实现了 <18%的总电压误差，同时实现了 >5kW 的功率水平。我们进行了输出频率的扫描和两个混合试验，包括一个实际的脑神经科学应用的刺激脉冲和一个娱乐性的试验，重现了著名的Arecibo信号。Abstract
Advances in power electronics have made it possible to achieve high power levels, e.g., reaching GW in grids, or alternatively high output bandwidths, e.g., beyond MHz in communication. Achieving both simultaneously, however, remains challenging. Various applications, ranging from efficient multichannel wireless power transfer to cutting-edge medical and neuroscience applications, are demanding both high power and wide bandwidth. Conventional inverters can achieve high power and high quality at grid or specific frequency ranges but lose their fidelity when reaching higher output frequencies. Resonant circuits can promise a high output frequency but only a narrow bandwidth. We overcome the hardware challenges by combining gallium-nitride (GaN) transistors with modular cascaded double-H bridge circuits and control that can manage typical timing and balancing issues. We developed a lightweight embedded control solution that includes an improved look-up-table digital synthesizer and a novel adaptive-bias-elimination nearest-level modulation. This solution effectively solves the conflict between a high power level and high output bandwidth and can--in contrast to previous approaches--in principle be scaled in both dimensions. Our prototype exhibits a frequency range from DC to 5 MHz with <18% total voltage distortion across the entire frequency spectrum, while achieving a power level of >5 kW. We conducted tests by sweeping the output frequency and two channel-mixing trials, which included a practical magnetogenetics-oriented stimulation pulse and an entertaining trial to reproduce the famous Arecibo message with the current spectrum.
摘要
Conventional inverters can achieve high power and high quality at grid or specific frequency ranges, but lose their fidelity when reaching higher output frequencies. Resonant circuits can promise high output frequencies but only have a narrow bandwidth. To overcome these hardware challenges, we combined gallium-nitride (GaN) transistors with modular cascaded double-H bridge circuits and control that can manage typical timing and balancing issues.We developed a lightweight embedded control solution that includes an improved look-up-table digital synthesizer and a novel adaptive-bias-elimination nearest-level modulation. This solution effectively solves the conflict between high power level and high output bandwidth and can, in contrast to previous approaches, be scaled in both dimensions. Our prototype exhibits a frequency range from DC to 5 MHz with <18% total voltage distortion across the entire frequency spectrum, while achieving a power level of >5 kW.We conducted tests by sweeping the output frequency and two channel-mixing trials, including a practical magnetogenetics-oriented stimulation pulse and an entertaining trial to reproduce the famous Arecibo message with the current spectrum.
Opportunistic Reflection in Reconfigurable Intelligent Surface-Assisted Wireless Networks
results: OMUR方法可以提高网络吞吐量和功率耗用率，并且可以在多用户多RIS情况下实现高速下载和上传。此外，我们还提出了一种简化版OMUR方法，通过随机阶段偏移来避免RIS通道估计的复杂性。Abstract
This paper focuses on multiple-access protocol design in a wireless network assisted by multiple reconfigurable intelligent surfaces (RISs). By extending the existing approaches in single-user or single-RIS cases, we present two benchmark schemes for this multi-user multi-RIS scenario. Inspecting their shortcomings, a simple but efficient method coined opportunistic multi-user reflection (OMUR) is proposed. The key idea is to opportunistically select the best user as the anchor for optimizing the RISs, and non-orthogonally transmitting all users' signals simultaneously. A simplified version of OMUR exploiting random phase shifts is also proposed to avoid the complexity of RIS channel estimation.
摘要
In Simplified Chinese:这篇论文关注无线网络中多个用户和多个智能表面（RIS）之间的协议设计。我们通过扩展单用户或单RIS情况下的现有方法，提出了多用户多RIS场景中的两个标准方案。此外，我们还提出了一种名为启发式多用户反射（OMUR）的简单 yet efficient方法，其中选择最佳用户作为RIS优化的anchor，并同时非正交发送所有用户的信号。此外，我们还提出了一种使用随机频率偏移的简化版OMUR，以避免RIS频率估计的复杂性。
A Simple Multiple-Access Design for Reconfigurable Intelligent Surface-Aided Systems
results: 研究人员提出了一种简单而高效的方法，可以在实际系统中实现高性能。通过随机相位偏移来避免RIS通道估计高开销。Abstract
This paper focuses on the design of transmission methods and reflection optimization for a wireless system assisted by a single or multiple reconfigurable intelligent surfaces (RISs). The existing techniques are either too complex to implement in practical systems or too inefficient to achieve high performance. To overcome the shortcomings of the existing schemes, we propose a simple but efficient approach based on \textit{opportunistic reflection} and \textit{non-orthogonal transmission}. The key idea is opportunistically selecting the best user that can reap the maximal gain from the optimally reflected signals via RIS. That is to say, only the channel state information of the best user is used for RIS reflection optimization, which can in turn lower complexity substantially. In addition, the second user is selected to superpose its signal on that of the primary user, where the benefits of non-orthogonal transmission, i.e., high system capacity and improved user fairness, are obtained. Additionally, a simplified variant exploiting random phase shifts is proposed to avoid the high overhead of RIS channel estimation.
摘要
Distributed Adaptive Signal Fusion for Fractional Programs
paper_authors: Cem Ates Musluoglu, Alexander Bertrand
for: 解决卫星感知网络中的空间滤波优化问题
methods: 使用分布式适应Signal Fusion（DASF）框架和一种基于迭代的解决方法
results: 提高了计算效率和精度，并且能够在带宽限制下进行分布式计算Abstract
The distributed adaptive signal fusion (DASF) framework allows to solve spatial filtering optimization problems in a distributed and adaptive fashion over a bandwidth-constrained wireless sensor network. The DASF algorithm requires each node to sequentially build a compressed version of the original network-wide problem and solve it locally. However, these local problems can still result in a high computational load at the nodes, especially when the required solver is iterative. In this paper, we study the particular case of fractional programs, i.e., problems for which the objective function is a fraction of two continuous functions, which indeed require such iterative solvers. By exploiting the structure of a commonly used method for solving fractional programs and interleaving it with the iterations of the standard DASF algorithm, we obtain a distributed algorithm with a significantly reduced computational cost compared to the straightforward application of DASF as a meta-algorithm. We prove convergence and optimality of this "fractional DASF" (FDASF) algorithm and demonstrate its performance via numerical simulations.
摘要
distributed adaptive signal fusion (DASF) 框架可以在分布式和适应性的方式下解决宽频率约束无线传感网络上的空间滤波优化问题。 DASF 算法要求每个节点先后建立一个压缩版本的原始网络范围内问题，并解决它们本地。然而，这些本地问题仍可能导致节点上的计算负担很大，特别是当需要的解决器是迭代的。在这篇论文中，我们研究了分数程序，即两个连续函数的比例的问题。这些问题确实需要迭代的解决器。我们利用一种广泛使用的方法解决分数程序的方法，并与标准 DASF 算法的迭代结合起来，从而获得了一个分布式算法，与直接在 DASF 作为元算法应用时的计算成本相比，有显著的减少。我们证明了 FDASF 算法的收敛和优化性，并通过数字实验来证明其性能。
Base Station Beamforming Design for Near-field XL-IRS Beam Training
results: numerical results indicate that the proposed AO based BS beamforming design outperforms the SVD/angle based BS beamforming in terms of training accuracy and achievable received SNR.Abstract
Existing research on extremely large-scale intelligent reflecting surface (XL-IRS) beam training has assumed the far-field channel model for base station (BS)-IRS link. However, this approach may cause degraded beam training performance in practice due to the near-field channel model of the BS-IRS link. To address this issue, we propose two efficient schemes to optimize BS beamforming for improving the XL-IRS beam training performance. Specifically, the first scheme aims to maximize total received signal power on the XL-IRS, which generalizes the existing angle based BS beamforming design and can be resolved using the singular value decomposition (SVD) method. The second scheme aims to maximize the $\ell_1$-norm of incident signals on the XL-IRS, which is shown to achieve the maximum received power at the user. To solve the non-convex $\ell_1$-norm maximization problem, we propose an eficient algorithm by using the alternating optimization (AO) technique. Numerical results show that the proposed AO based BS beamforming design outperforms the SVD/angle based BS beamforming in terms of training accuracy and achievable received signal-to-noise ratio (SNR).
摘要
原研究中的巨大智能反射Surface（XL-IRS）的杆形训练假设了BS-IRS链路的远场通道模型。然而，这种方法可能会导致实际中的杆形训练性能下降，因为BS-IRS链路的近场通道模型。为解决这个问题，我们提出了两种高效的方案来优化BS杆形干扰。 Specifically, the first scheme aims to maximize the total received signal power on the XL-IRS, which generalizes the existing angle-based BS beamforming design and can be resolved using the singular value decomposition (SVD) method. The second scheme aims to maximize the $\ell_1$-norm of incident signals on the XL-IRS, which is shown to achieve the maximum received power at the user. To solve the non-convex $\ell_1$-norm maximization problem, we propose an efficient algorithm by using the alternating optimization (AO) technique. Numerical results show that the proposed AO-based BS beamforming design outperforms the SVD/angle-based BS beamforming in terms of training accuracy and achievable received signal-to-noise ratio (SNR).Here's the translation of the text in Traditional Chinese:先前的研究中的巨大智能反射Surface（XL-IRS）的杆形训练假设了BS-IRS链路的远场通道模型。然而，这种方法可能会导致实际中的杆形训练性能下降，因为BS-IRS链路的近场通道模型。为解决这个问题，我们提出了两种高效的方案来优化BS杆形干扰。 Specifically, the first scheme aims to maximize the total received signal power on the XL-IRS, which generalizes the existing angle-based BS beamforming design and can be resolved using the singular value decomposition (SVD) method. The second scheme aims to maximize the $\ell_1$-norm of incident signals on the XL-IRS, which is shown to achieve the maximum received power at the user. To solve the non-convex $\ell_1$-norm maximization problem, we propose an efficient algorithm by using the alternating optimization (AO) technique. Numerical results show that the proposed AO-based BS beamforming design outperforms the SVD/angle-based BS beamforming in terms of training accuracy and achievable received signal-to-noise ratio (SNR).
Comparing Iterative and Least-Squares Based Phase Noise Tracking in Receivers with 1-bit Quantization and Oversampling
results: Iterative phase noise tracking 在高信噪比下具有较低的估计误差方差，但是它对 spectral efficiency 的提高几乎只有微妙的提高，即高于 Nyquist 幂 ZXM 模ulation。Abstract
High data rates require vast bandwidths, that can be found in the sub-THz band, and high sampling frequencies, which are predicted to lead to a problematically high analog-to-digital converter (ADC) power consumption. It was proposed to use 1-bit ADCs to mitigate this problem. Moreover, oscillator phase noise is predicted to be especially high at sub-THz carrier frequencies. For synchronization the phase must be tracked based on 1-bit quantized observations. We study iterative data-aided phase estimation, i.e., the expectation-maximization and the Fisher-scoring algorithm, compared to least-squares (LS) phase estimation. For phase interpolation at the data symbols, we consider the Kalman filter and the Rauch-Tung-Striebel algorithm. Compared to LS estimation, iterative phase noise tracking leads to a significantly lower estimation error variance at high signal-to-noise ratios. However, its benefit for the spectral efficiency using zero-crossing modulation (ZXM) is limited to marginal gains for high faster-than-Nyquist signaling factors, i.e., higher order ZXM modulation.
摘要
高数据率需要庞大的带宽，可以在Sub-THz频段找到，同时需要高的采样频率，这将导致问题atically高的Analog-to-Digital Converter（ADC）电力消耗。提出使用1比特ADC来缓解这个问题。此外，oscillator阶段噪声预测在Sub-THz振荡频率下特别高。为了同步化，需要根据1比特量化的观察结果追踪阶段。我们研究了iterative数据援引phase估计算法，包括期望最大化算法和fisherscoring算法，与最小二乘（LS）phase估计相比。在数据符号上进行phase interpolating时，我们考虑了卡尔曼筛和Rauch-Tung-Striebel算法。与LS估计相比，iterative phase噪声追踪导致高信号噪声比在高信号至噪声比下显著降低。然而，对于频率使用零交叉模ulation（ZXM）的spectral efficiency来说，其利益受到高速于Nyquist频率因子的限制，即高阶ZXM模ulation。
Tuning of Ray-Based Channel Model for 5G Indoor Industrial Scenarios
paper_authors: Gurjot Singh Bhatia, Yoann Corre, Marco Di Renzo
for: 本文提出了一种用于生成5G工业互联网的决定性通道模型的创新方法。
methods: 本文使用了折射跟踪（RT）通道模拟器，可以很好地捕捉到各种工业环境下的具体特性。
results: 本文对3.7GHz和28GHz两频段的5G工业网络进行了比较，并与文献中的场测数据进行了比较，以生成准确的折射基本通道模型。Abstract
This paper presents an innovative method that can be used to produce deterministic channel models for 5G industrial internet-of-things (IIoT) scenarios. Ray-tracing (RT) channel emulation can capture many of the specific properties of a propagation scenario, which is incredibly beneficial when facing various industrial environments and deployment setups. But the environment's complexity, composed of many metallic objects of different sizes and shapes, pushes the RT tool to its limits. In particular, the scattering or diffusion phenomena can bring significant components. Thus, in this article, the Volcano RT channel simulation is tuned and benchmarked against field measurements found in the literature at two frequencies relevant to 5G industrial networks: 3.7 GHz (mid-band) and 28 GHz (millimeter-wave (mmWave) band), to produce calibrated ray-based channel model. Both specular and diffuse scattering contributions are calculated. Finally, the tuned RT data is compared to measured large-scale parameters, such as the power delay profile (PDP), the cumulative distribution function (CDF) of delay spreads (DSs), both in line-of-sight (LoS) and non-LoS (NLoS) situations and relevant IIoT channel properties are further explored.
摘要
To address these challenges, the Volcano RT channel simulation is tuned and benchmarked against field measurements found in the literature at two frequencies relevant to 5G industrial networks: 3.7 GHz (mid-band) and 28 GHz (millimeter-wave band). The calibrated ray-based channel model takes into account both specular and diffuse scattering contributions.The tuned RT data is compared to measured large-scale parameters, such as the power delay profile (PDP), the cumulative distribution function (CDF) of delay spreads (DSs), both in line-of-sight (LoS) and non-LoS (NLoS) situations. Additionally, relevant IIoT channel properties are further explored.
Hybrid NOMA assisted Integrated Sensing and Communication via RIS
results: 根据实验结果，提出的低复杂度交叉优化算法可以提高最小探测响应强度（MBPG），并且对探测和通信之间的负荷调整进行分析。Abstract
This paper investigates the optimization of reconfigurable intelligent surface (RIS) in an integrated sensing and communication (ISAC) system. \red{To meet the demand of growing number of devices, power domain non-orthogonal multiple access (NOMA) is considered. However, traditional NOMA with a large number of devices is challenging due to large decoding delay and propagation error introduced by successive interference cancellation (SIC). Thus, OMA is integrated into NOMA to support more devices}. We formulate a max-min problem to optimize the sensing beampattern \red{with constraints on communication rate}, through joint power allocation, active beamforming and RIS phase shift design. To solve the non-convex problem with a non-smooth objective function, we propose a low complexity alternating optimization (AO) algorithm, where a closed form expression for the intra-cluster power allocation (intra-CPA) is derived, and penalty and successive convex approximation (SCA) methods are used to optimize the beamforming and phase shift design. Simulation results show the effectiveness of the proposed algorithm in terms of improving minimum beampattern gain (MBPG) compared with other baselines. Furthermore, the trade-off between sensing and communication is analyzed and demonstrated in the simulation results.
摘要
The paper formulates a max-min problem to optimize the sensing beampattern with constraints on communication rate, using joint power allocation, active beamforming, and RIS phase shift design. To solve the non-convex problem with a non-smooth objective function, a low-complexity alternating optimization (AO) algorithm is proposed. This algorithm includes a closed-form expression for intra-cluster power allocation (intra-CPA), penalty and successive convex approximation (SCA) methods for optimizing beamforming and phase shift design.Simulation results show the effectiveness of the proposed algorithm in terms of improving minimum beampattern gain (MBPG) compared to other baselines. Additionally, the trade-off between sensing and communication is analyzed and demonstrated in the simulation results.
Dynamic Simulation of Three-Phase Induction Machines Under Eccentricity Conditions
paper_authors: Jianan Liu, Guanhua Ding, Yuxuan Xia, Jinping Sun, Tao Huang, Lihua Xie, Bing Zhu for:这篇论文旨在探讨在现实世界ADAS和自动驾驶场景中的在线3D多对象跟踪（MOT）问题，具体来说是对LiDAR和4D影像雷达点云的点对象跟踪（POT）和扩展对象跟踪（EOT）两种不同的方法进行系统性的调研。methods:这篇论文使用了三种不同的方法进行比较：传统的TBD-POT方法、最近研究的JDT-EOT方法以及我们提出的TBD-EOT方法。这些方法在两个开源的4D影像雷达数据集上进行了广泛的评估。results:实验结果表明，传统的TBD-POT方法在在线3D MOT中具有高跟踪性和低计算复杂度，而我们提出的TBD-EOT方法在某些情况下可能超越其性能。然而，JDT-EOT方法在评估场景中表现不佳，并且经过分析多种评价指标和视觉化分析后，我们提出了改进其性能的可能性。这些研究为未来4D影像雷达基于在线3D MOT的发展提供了首个和重要的指南。Abstract
Online 3D multi-object tracking (MOT) has recently received significant research interests due to the expanding demand of 3D perception in advanced driver assistance systems (ADAS) and autonomous driving (AD). Among the existing 3D MOT frameworks for ADAS and AD, conventional point object tracking (POT) framework using the tracking-by-detection (TBD) strategy has been well studied and accepted for LiDAR and 4D imaging radar point clouds. In contrast, extended object tracking (EOT), another important framework which accepts the joint-detection-and-tracking (JDT) strategy, has rarely been explored for online 3D MOT applications. This paper provides the first systematical investigation of the EOT framework for online 3D MOT in real-world ADAS and AD scenarios. Specifically, the widely accepted TBD-POT framework, the recently investigated JDT-EOT framework, and our proposed TBD-EOT framework are compared via extensive evaluations on two open source 4D imaging radar datasets: View-of-Delft and TJ4DRadSet. Experiment results demonstrate that the conventional TBD-POT framework remains preferable for online 3D MOT with high tracking performance and low computational complexity, while the proposed TBD-EOT framework has the potential to outperform it in certain situations. However, the results also show that the JDT-EOT framework encounters multiple problems and performs inadequately in evaluation scenarios. After analyzing the causes of these phenomena based on various evaluation metrics and visualizations, we provide possible guidelines to improve the performance of these MOT frameworks on real-world data. These provide the first benchmark and important insights for the future development of 4D imaging radar-based online 3D MOT.
摘要
在线3D多对象跟踪（MOT）最近受到了广泛的研究兴趣，这主要归功于自动驾驶系统（ADAS）和自主驱动（AD）的扩展需求。在现有的3D MOT框架中，使用跟踪检测（TBD）策略的点对象跟踪（POT）框架已经广泛研究和应用于激光雷达和4D图像雷达的点云数据。然而，接受联合检测与跟踪（JDT）策略的延长对象跟踪（EOT）框架在在线3D MOT应用中 rarely 被研究。本文提供了在实际ADAS和AD场景中的首次系统性的EOT框架比较，包括广泛接受的TBD-POT框架、最近研究的JDT-EOT框架以及我们的提议的TBD-EOT框架。经过广泛的评估于两个开源4D图像雷达数据集：View-of-Delft和TJ4DRadSet，实验结果显示， convent ional TBD-POT框架在在线3D MOT中具有高跟踪性和低计算复杂度，而我们提议的TBD-EOT框架在某些情况下具有超越TBD-POT框架的潜在优势。然而，结果也表明，JDT-EOT框架在评估场景中存在多个问题，并且表现不佳。经过根据多种评价指标和视觉化分析，我们提供了可能的改进方向，这些提供了首次的4D图像雷达基于在线3D MOT的 Referenced bencmark和重要的指导。
Non-parametric Ensemble Empirical Mode Decomposition for extracting weak features to identify bearing defects
results: 比较NPCEEMD和现有方法，NPCEEMD的模式混合度较低Here’s a more detailed explanation of each point:
for: The paper is written for identifying bearing defects using weak features, specifically using the proposed NPCEEMD method.
methods: The paper proposes a non-parametric complementary ensemble empirical mode decomposition (NPCEEMD) method for identifying bearing defects. This method is non-parametric, meaning it does not require defining the ideal signal-to-noise ratio (SNR) or the number of ensembles every time while processing the signals.
results: The paper presents simulation results showing that the proposed NPCEEMD method has less mode mixing than existing decomposition methods. Additionally, the method is applied to experimental data, and the resulting signal is computed using the envelope spectrum to confirm the presence of defects.Abstract
A non-parametric complementary ensemble empirical mode decomposition (NPCEEMD) is proposed for identifying bearing defects using weak features. NPCEEMD is non-parametric because, unlike existing decomposition methods such as ensemble empirical mode decomposition, it does not require defining the ideal SNR of noise and the number of ensembles, every time while processing the signals. The simulation results show that mode mixing in NPCEEMD is less than the existing decomposition methods. After conducting in-depth simulation analysis, the proposed method is applied to experimental data. The proposed NPCEEMD method works in following steps. First raw signal is obtained. Second, the obtained signal is decomposed. Then, the mutual information (MI) of the raw signal with NPCEEMD-generated IMFs is computed. Further IMFs with MI above 0.1 are selected and combined to form a resulting signal. Finally, envelope spectrum of resulting signal is computed to confirm the presence of defect.
摘要
“一种非Parametric complementary ensemble empirical mode decomposition（NPCEEMD）是用于发现推挽缺陷的方法，使用弱特征。NPCEEMD非 Parametric，因为它不需要每次处理信号时定义理想噪声水平和数量的集合。模拟结果显示，NPCEEMD中的模式混合度比现有的分解方法更低。经过深入的模拟分析，提议的方法应用到实验数据中。NPCEEMD方法的步骤如下：首先获取原始信号；第二，将获取的信号进行分解；然后计算原始信号与NPCEEMD生成的IMF的相互信息（MI）；进一步选择MI大于0.1的IMF并将其组合成一个结果信号；最后，计算结果信号的响应特征来确认缺陷存在。”Note: "IMF" stands for "intrinsic mode function".
Massive Access of Static and Mobile Users via Reconfigurable Intelligent Surfaces: Protocol Design and Performance Analysis
results: simulations 表明，提议的 MAC 协议在系统吞吐量和访问公平性两个方面具有优于标准协议，但是存在访问公平性和系统吞吐量之间的贸易关系。Abstract
The envisioned wireless networks of the future entail the provisioning of massive numbers of connections, heterogeneous data traffic, ultra-high spectral efficiency, and low latency services. This vision is spurring research activities focused on defining a next generation multiple access (NGMA) protocol that can accommodate massive numbers of users in different resource blocks, thereby, achieving higher spectral efficiency and increased connectivity compared to conventional multiple access schemes. In this article, we present a multiple access scheme for NGMA in wireless communication systems assisted by multiple reconfigurable intelligent surfaces (RISs). In this regard, considering the practical scenario of static users operating together with mobile ones, we first study the interplay of the design of NGMA schemes and RIS phase configuration in terms of efficiency and complexity. Based on this, we then propose a multiple access framework for RIS-assisted communication systems, and we also design a medium access control (MAC) protocol incorporating RISs. In addition, we give a detailed performance analysis of the designed RIS-assisted MAC protocol. Our extensive simulation results demonstrate that the proposed MAC design outperforms the benchmarks in terms of system throughput and access fairness, and also reveal a trade-off relationship between the system throughput and fairness.
摘要
将来的无线网络视图包括提供庞大量连接、不同数据流量、ultra-高频率效率和低延迟服务。这一视图激发了研究人员关于定义下一代多接入（NGMA）协议的研究活动，以便在不同资源块中承载大量用户，从而实现更高的频率效率和连接性。在这篇文章中，我们介绍了一种基于RIS的NGMA协议在无线通信系统中的应用。在这种情况下，我们首先研究了NGMA协议的设计和RIS相位配置之间的关系，并对系统效率和复杂性进行了分析。然后，我们提出了一种基于RIS的通信系统多Access框架，并设计了一种嵌入RIS的媒体访问控制协议（MAC）协议。此外，我们对提出的MAC协议进行了详细的性能分析。我们的广泛的 simulations结果表明，提出的MAC设计在系统吞吐量和访问公平性方面都有优于标准准确，并且还发现了系统吞吐量和公平性之间的负相关性。
Performance Bounds for Near-Field Localization with Widely-Spaced Multi-Subarray mmWave/THz MIMO
results: 研究发现，在某些情况下，WSMS的CRB小于均勋阵列的CRB，并且提供了各种系统特性的可见性和实验验证。Abstract
This paper investigates the potential of near-field localization using widely-spaced multi-subarrays (WSMSs) and analyzing the corresponding angle and range Cram\'er-Rao bounds (CRBs). By employing the Riemann sum, closed-form CRB expressions are derived for the spherical wavefront-based WSMS (SW-WSMS). We find that the CRBs can be characterized by the angular span formed by the line connecting the array's two ends to the target, and the different WSMSs with same angular spans but different number of subarrays have identical normalized CRBs. We provide a theoretical proof that, in certain scenarios, the CRB of WSMSs is smaller than that of uniform arrays. We further yield the closed-form CRBs for the hybrid spherical and planar wavefront-based WSMS (HSPW-WSMS), and its components can be seen as decompositions of the parameters from the CRBs for the SW-WSMS. Simulations are conducted to validate the accuracy of the derived closed-form CRBs and provide further insights into various system characteristics. Basically, this paper underscores the high resolution of utilizing WSMS for localization, reinforces the validity of adopting the HSPW assumption, and, considering its applications in communications, indicates a promising outlook for integrated sensing and communications based on HSPW-WSMSs.
摘要