paper_authors: Zahra Esmaeilbeig, Kumar Vijay Mishra, Arian Eamaz, Mojtaba Soltanalian
for: 这篇论文是关于智能反射表面（IRS）的优化部署和探测应用的研究。
methods: 本论文使用了最大共识度来决定多个IRS平台的部署，以优化探测应用。
results: 研究表明，使用最大共识度作为优化标准可以实现约63%的最差性能保证。Abstract
Intelligent reflecting surfaces (IRS) and their optimal deployment are the new technological frontier in sensing applications. Recently, IRS have demonstrated potential in advancing target estimation and detection. While the optimal phase-shift of IRS for different tasks has been studied extensively in the literature, the optimal placement of multiple IRS platforms for sensing applications is less explored. In this paper, we design the placement of IRS platforms for sensing by maximizing the mutual information. In particular, we use this criterion to determine an approximately optimal placement of IRS platforms to illuminate an area where the target has a hypothetical presence. After demonstrating the submodularity of the mutual information criteria, we tackle the design problem by means of a constant-factor approximation algorithm for submodular optimization. Numerical results are presented to validate the proposed submodular optimization framework for optimal IRS placement with worst case performance bounded to $1-1/e\approx 63 \%$.
摘要
《智能反射表面（IRS）和其最佳部署》是当今探测应用的新技术前沿。最近，IRS已经表现出在目标估计和检测方面的潜力。虽然literature中对不同任务的IRS阶段的优化已经得到了广泛的研究，但IRS平台的多个部署 для探测应用还尚未得到了充分的研究。在这篇论文中，我们设计了IRS平台的部署方式，以最大化互信息。特别是，我们使用这个标准来确定IRS平台的投射方式，以照明假设存在目标的区域。我们首先证明了互信息标准的子模度性，然后使用子模度优化算法来解决设计问题。 num = 1-1/e ≈ 63%。Here's the breakdown of the translation:* "Intelligent reflecting surfaces" is translated as "智能反射表面" (Zhīngnéng jiànshì biānshì)* "and their optimal deployment" is translated as "以及其最佳部署" (yǐngqí yǔ jiāojiā bèipiāo)* "are the new technological frontier in sensing applications" is translated as "是当今探测应用的新技术前沿" (shì dāngjīn tàncéng yìngyùn yìshì)* "Recently, IRS have demonstrated potential in advancing target estimation and detection" is translated as "最近，IRS已经表现出在目标估计和检测方面的潜力" (zuìjìn, IRS yǐjīng bìngxìn zhìyì yìshì)* "While the optimal phase-shift of IRS for different tasks has been studied extensively in the literature" is translated as "虽然literature中对不同任务的IRS阶段的优化已经得到了广泛的研究" ( substitude "phase-shift" with "阶段" (jìděn) in Chinese)* "the optimal placement of multiple IRS platforms for sensing applications is less explored" is translated as "IRS平台的多个部署 для探测应用还尚未得到了充分的研究" (IRS píngtiān de duō gè bèipiāo yǐng yìshì)* "In this paper, we design the placement of IRS platforms for sensing by maximizing the mutual information" is translated as "在这篇论文中，我们设计了IRS平台的部署方式，以最大化互信息" (substitute "placing" with "部署" (bèipiāo) in Chinese)* "In particular, we use this criterion to determine an approximately optimal placement of IRS platforms to illuminate an area where the target has a hypothetical presence" is translated as "特别是，我们使用这个标准来确定IRS平台的投射方式，以照明假设存在目标的区域" (substitute "illuminate" with "照明" (zhàoqǐng) in Chinese)* "After demonstrating the submodularity of the mutual information criteria" is translated as "我们首先证明了互信息标准的子模度性" (substitute "submodularity" with "子模度性" (zǐmódegè) in Chinese)* "we tackle the design problem by means of a constant-factor approximation algorithm for submodular optimization" is translated as "然后使用子模度优化算法来解决设计问题" (substitute "constant-factor" with "常数因子" (chángxīng yǐngxí) in Chinese)* "Numerical results are presented to validate the proposed submodular optimization framework for optimal IRS placement with worst case performance bounded to $1-1/e\approx 63\%$" is translated as " num = 1-1/e ≈ 63%。我们提供的子模度优化框架的数值结果，以验证优化结果的可行性" (substitute "worst case" with "最差情况" (zuìjì) in Chinese)
Piezoelectric Sensors for Real-time Monitoring and Quality Control in Additive Manufacturing
results: 研究发现， piezoelectric 感应器在实时监测和质量控制方面具有广泛的应用前景和潜在价值，对于新手和专业人士都具有启发性和实用性。Abstract
Within the ever-evolving landscape of engineering, particularly in the dynamic domain of additive In manufacturing, a pursuit of precision and excellence in production processes takes centre stage. This research , This paper serves to give a comprehensive understanding of piezoelectric sensors, a topic that is both academically engaging and of practical significance, catering to both seasoned experts and those newly venturing into the field. Additive manufacturing, lauded for its groundbreaking potential, underscores the imperative of rigorous quality control. This introduces piezoelectric sensors, devices that may be unfamiliar to many but possess considerable potential. This paper embarks on a methodical journey, commencing with an introductory elucidation of the piezoelectric effect. It then advances to the vital role of piezoelectric sensors in real-time monitoring and quality control, unveiling their potential and relevance for newcomers and seasoned professionals alike. This research, structured systematically from fundamental principles to pragmatic applications, presents findings that are not only academically informative but also represent a substantial stride towards achieving precision and high-quality manufacturing processes in the engineering field.
摘要
在工程领域中，特别是在加工制造领域，精度和excel在生产过程中拥有中心舞台。这篇研究，这篇论文旨在为涉及到 piezoelectric 传感器的学术研究和实践提供全面的理解，它不仅对有经验的专家有启发，还对新进入该领域的人有很大的启示。加工制造被赞赏为创新的潜力，强调了严格的质量控制的重要性。这使得 piezoelectric 传感器成为了一种可能新的和有潜力的技术。这篇论文从基本原理开始，逐步向实践应用，对新手和经验手都有很大的启示。这项研究不仅是学术上的探索，也是在工程领域实现精度和高质量生产过程的一大步进。
FAS-assisted NOMA Short-Packet Communication Systems
paper_authors: Jianchao Zheng, Tuo Wu, Xiazhi Lai, Cunhua Pan, Maged Elkashlan, Kai-Kit Wong
for: investigate a fluid antenna system (FAS)-assisted downlink non-orthogonal multiple access (NOMA) for short-packet communications.
methods: base station (BS) adopts a single fixed antenna, while both the central user (CU) and the cell-edge user (CEU) are equipped with a FAS.
results: the diversity order for CU and CEU is $N$, indicating that the system performance can be considerably improved by increasing $N$.Here’s the full version in Traditional Chinese:
results: FAS帮助下，CU和CEU的多标题状况下的系统性能可以随N的增加而提高。Abstract
In this paper, we investigate a fluid antenna system (FAS)-assisted downlink non-orthogonal multiple access (NOMA) for short-packet communications. The base station (BS) adopts a single fixed antenna, while both the central user (CU) and the cell-edge user (CEU) are equipped with a FAS. Each FAS comprises $N$ flexible positions (also known as ports), linked to $N$ arbitrarily correlated Rayleigh fading channels. We derive expressions for the average block error rate (BLER) of the FAS-assisted NOMA system and provide asymptotic BLER expressions. We determine that the diversity order for CU and CEU is $N$, indicating that the system performance can be considerably improved by increasing $N$. Simulation results validate the great performance of FAS.
摘要
在这篇论文中，我们研究了一个流体天线系统（FAS）助动下link非对称多接入（NOMA） для短包通信。基站（BS）采用单一固定天线，而中央用户（CU）和边缘用户（CEU）均配备了FAS。每个FAS包括 $N$ 个 flexible位（也称为端口），与 $N$ 个互相相关的干扰谱噪抖动通道相连。我们 derive了 FAS-assisted NOMA 系统的平均块错误率（BLER）表达式，并提供了各种各样的 BLER 表达式。我们发现，CU 和 CEU 的多普通性顺序是 $N$，这表明，通过增加 $N$，系统性能可以得到显著改善。实验结果证明了 FAS 的优秀性能。
How do the resting EEG preprocessing states affect the outcomes of postprocessing?
methods: 研究人员使用了新 York 头部模型和多变量自 regression 模型来生成清晰 EEG（CE）作为参考数据，然后通过在 CE 基础上增加 Gaussian 噪声和失去大脑活动来生成预处理不足（IPE）和过度预处理（EPE）数据。
results: 研究人员发现，预处理不足和过度预处理都会导致后处理结果与 CE 之间的偏差，特别是在频域、空间和时间领域的 Statistics、多通道能量、跨 Spectra、源 imaging 粒度和贝叶率等方面。此外，研究人员还发现，PaLOSi 指标与预处理状态的变化有 statistically significative 相关性。Abstract
Plenty of artifact removal tools and pipelines have been developed to correct the EEG recordings and discover the values below the waveforms. Without visual inspection from the experts, it is susceptible to derive improper preprocessing states, like the insufficient preprocessed EEG (IPE), and the excessive preprocessed EEG (EPE). However, little is known about the impacts of IPE or EPE on the postprocessing in the frequency, spatial and temporal domains, particularly as to the spectra and the functional connectivity (FC) analysis. Here, the clean EEG (CE) was synthesized as the ground truth based on the New-York head model and the multivariate autoregressive model. Later, the IPE and the EPE were simulated by injecting the Gaussian noise and losing the brain activities, respectively. Then, the impacts on postprocessing were quantified by the deviation caused by the IPE or EPE from the CE as to the 4 temporal statistics, the multichannel power, the cross spectra, the dispersion of source imaging, and the properties of scalp EEG network. Lastly, the association analysis was performed between the PaLOSi metric and the varying trends of postprocessing with the evolution of preprocessing states. This study shed light on how the postprocessing outcomes are affected by the preprocessing states and PaLOSi may be a potential effective quality metric.
摘要
很多遗物除去工具和管道已经开发出来 corrections EEG 记录，以便发现下面波形的值。而不经visual inspection from the experts，可能导致 derivation improper preprocessing states, such as insufficient preprocessed EEG (IPE) and excessive preprocessed EEG (EPE). However, little is known about the impacts of IPE or EPE on the postprocessing in the frequency, spatial, and temporal domains, particularly as to the spectra and the functional connectivity (FC) analysis.Here, the clean EEG (CE) was synthesized as the ground truth based on the New-York head model and the multivariate autoregressive model. Later, the IPE and the EPE were simulated by injecting Gaussian noise and losing brain activities, respectively. Then, the impacts on postprocessing were quantified by the deviation caused by the IPE or EPE from the CE as to the 4 temporal statistics, the multichannel power, the cross spectra, the dispersion of source imaging, and the properties of scalp EEG network. Lastly, the association analysis was performed between the PaLOSi metric and the varying trends of postprocessing with the evolution of preprocessing states. This study shed light on how the postprocessing outcomes are affected by the preprocessing states and PaLOSi may be a potential effective quality metric.
On the Sum Secrecy Rate of Multi-User Holographic MIMO Networks
results: 研究发现，采用adaptive/灵活的发射功率分配（PA）可以在高信号噪声比（SNR） régime中获得显著性能提升，对两个用户情况下可以获得更多于100%的增强。Abstract
The emerging concept of extremely-large holographic multiple-input multiple-output (HMIMO), beneficial from compactly and densely packed cost-efficient radiating meta-atoms, has been demonstrated for enhanced degrees of freedom even in pure line-of-sight conditions, enabling tremendous multiplexing gain for the next-generation communication systems. Most of the reported works focus on energy and spectrum efficiency, path loss analyses, and channel modeling. The extension to secure communications remains unexplored. In this paper, we theoretically characterize the secrecy capacity of the HMIMO network with multiple legitimate users and one eavesdropper while taking into consideration artificial noise and max-min fairness. We formulate the power allocation (PA) problem and address it by following successive convex approximation and Taylor expansion. We further study the effect of fixed PA coefficients, imperfect channel state information, inter-element spacing, and the number of Eve's antennas on the sum secrecy rate. Simulation results show that significant performance gain with more than 100\% increment in the high signal-to-noise ratio (SNR) regime for the two-user case is obtained by exploiting adaptive/flexible PA compared to the case with fixed PA coefficients.
摘要
新的概念——超大型杂点多输入多输出（HMIMO）技术，具有高度压缩和高密度的成本效益的卫星体，已经在纯线路条件下实现了更高的自由度，这将导致下一代通信系统的多重化增量。大多数报道的研究都集中在能量和频率效益、距离损失分析和通道模型。然而，安全通信的扩展还没有被探讨。在这篇论文中，我们理论上Characterize HMIMO网络的机密容量，并考虑人工噪声和最大最小公平。我们将 transmit power allocation（PA）问题，通过Successive Convex Approximation和Taylor扩展解决。我们进一步研究了固定PA系数、不完全的通道状态信息、元素间距离和贝娅的天线数量对Sum secrecy rate的影响。实验结果表明，在高信号噪声比（SNR）区间，通过适应/灵活PA比与固定PA系数相比，可以获得高达100%的性能提升。
A Coordinate Descent Approach to Atomic Norm Minimization
results: 该方法在数学上证明可以快速地求解原子范数最小化问题，并且在大规模问题中实现了高效的计算。通过对比ADMM和自定义内点SDP解决方案，该方法在解决稀疏问题方面明显更快。Abstract
Atomic norm minimization is of great interest in various applications of sparse signal processing including super-resolution line-spectral estimation and signal denoising. In practice, atomic norm minimization (ANM) is formulated as a semi-definite programming (SDP) which is generally hard to solve. This work introduces a low-complexity, matrix-free method for solving ANM. The method uses the framework of coordinate descent and exploits the sparsity-induced nature of atomic-norm regularization. Specifically, an equivalent, non-convex formulation of ANM is first proposed. It is then proved that applying the coordinate descent framework on the non-convex formulation leads to convergence to the global optimal point. For the case of a single measurement vector of length N in discrete fourier transform (DFT) basis, the complexity of each iteration in the coordinate descent procedure is O(N log N ), rendering the proposed method efficient even for large-scale problems. The proposed coordinate descent framework can be readily modified to solve a variety of ANM problems, including multi-dimensional ANM with multiple measurement vectors. It is easy to implement and can essentially be applied to any atomic sets as long as a corresponding rank-1 problem can be solved. Through extensive numerical simulations, it is verified that for solving sparse problems the proposed method is much faster than the alternating direction method of multipliers (ADMM) or the customized interior point SDP solver.
摘要
“原子 нор 最小化是各种各样的应用，包括超解析和信号噪声除除。但是在实践中，原子 norm 最小化（ANM）通常被表示为半definite 程序（SDP），这通常很难解决。这项工作提出了一种低复杂度、缺少矩阵的方法来解决 ANM。该方法使用坐标 descent 框架，利用原子规定的稀疏性来减少计算复杂性。具体来说，首先提出了 ANM 的非конvex 表述，然后证明通过坐标 descent 框架处理非конvex 表述可以达到全局最优点。在单个测量向量长度为 N 的抽象快推（DFT）基础下，每次迭代的复杂度为 O(N log N)，这使得提出的方法在大规模问题上高效。此外，这种坐标 descent 框架可以轻松地修改，以解决多维 ANM 问题，包括多个测量向量。它易于实现，可以适用于任何原子集，只要可以解决相应的 rank-1 问题。经过广泛的数值实验，证明了用于解决稀疏问题的提出方法比 ADMM 或自定义内点 SDP 解决器更快。”
Spatial Sigma-Delta Modulation for Coarsely Quantized Massive MIMO Downlink: Flexible Designs by Convex Optimization
results: 数字实现中使用Sigma-Delta模ulation可以达到近似于无量化的性能，但需要考虑angle sector和数量化级别等因素。Abstract
This paper considers the context of multiuser massive MIMO downlink precoding with low-resolution digital-to-analog converters (DACs) at the transmitter. This subject is motivated by the consideration that it is expensive to employ high-resolution DACs for practical massive MIMO implementations. The challenge with using low-resolution DACs is to overcome the detrimental quantization error effects. Recently, spatial Sigma-Delta modulation has arisen as a viable way to put quantization errors under control. This approach takes insight from temporal Sigma-Delta modulation in classical DAC studies. Assuming a 1D uniform linear transmit antenna array, the principle is to shape the quantization errors in space such that the shaped quantization errors are pushed away from the user-serving angle sector. In the previous studies, spatial Sigma-Delta modulation was performed by direct application of the basic first- and second-order modulators from the Sigma-Delta literature. In this paper, we develop a general Sigma-Delta modulator design framework for any given order, for any given number of quantization levels, and for any given angle sector. We formulate our design as a problem of maximizing the signal-to-quantization-and-noise ratios experienced by the users. The formulated problem is convex and can be efficiently solved by available solvers. Our proposed framework offers the alternative option of focused quantization error suppression in accordance with channel state information. Our framework can also be extended to 2D planar transmit antenna arrays. We perform numerical study under different operating conditions, and the numerical results suggest that, given a moderate number of quantization levels, say, 5 to 7 levels, our optimization-based Sigma-Delta modulation schemes can lead to bit error rate performance close to that of the unquantized counterpart.
摘要
Factor Graph Processing for Dual-Blind Deconvolution at ISAC Receiver
results: 实验结果表明，使用了效果差分方法（EM）算法可以高效地估算无知变量，包括噪声存在的情况下。Abstract
Integrated sensing and communications (ISAC) systems have gained significant interest because of their ability to jointly and efficiently access, utilize, and manage the scarce electromagnetic spectrum. The co-existence approach toward ISAC focuses on the receiver processing of overlaid radar and communications signals coming from independent transmitters. A specific ISAC coexistence problem is dual-blind deconvolution (DBD), wherein the transmit signals and channels of both radar and communications are unknown to the receiver. Prior DBD works ignore the evolution of the signal model over time. In this work, we consider a dynamic DBD scenario using a linear state space model (LSSM) such that, apart from the transmit signals and channels of both systems, the LSSM parameters are also unknown. We employ a factor graph representation to model these unknown variables. We avoid the conventional matrix inversion approach to estimate the unknown variables by using an efficient expectation-maximization algorithm, where each iteration employs a Gaussian message passing over the factor graph structure. Numerical experiments demonstrate the accurate estimation of radar and communications channels, including in the presence of noise.
摘要
интегрированные сенсинг и коммуникации (ISAC) 系统在过去几年中得到了广泛的关注，因为它们可以同时和有效地访问、利用和管理有限的电磁 спектrum。在 ISAC 的共存方法中，接收器处理来自独立的发送器的掩码过的雷达和通信信号。特定的 ISAC 共存问题是双目掩码分解 (DBD)，其中雷达和通信系统的发送信号和通道都是接收器不知道的。先前的 DBD 工作忽略了信号模型的时间演化。在这种情况下，我们使用线性状态空间模型 (LSSM)，以便除了雷达和通信系统的发送信号和通道之外，还不知道 LSSM 参数。我们使用因果图表示这些未知变量。我们避免了传统的矩阵逆解方法，而是使用高效的期望最大化算法，每次迭代都使用 Gaussian 消息传递在因果图结构上。实验示出了准确地估计雷达和通信通道，包括在噪声存在的情况下。
Photoplethysmography based atrial fibrillation detection: an updated review from July 2019
results: 研究发现，使用 PPG 技术可以准确地检测 AF，并且可以提高患者的健康状况。同时，研究还发现了在这个领域存在的挑战。Abstract
Atrial fibrillation (AF) is a prevalent cardiac arrhythmia associated with significant health ramifications, including an elevated susceptibility to ischemic stroke, heart disease, and heightened mortality. Photoplethysmography (PPG) has emerged as a promising technology for continuous AF monitoring for its cost-effectiveness and widespread integration into wearable devices. Our team previously conducted an exhaustive review on PPG-based AF detection before June 2019. However, since then, more advanced technologies have emerged in this field. This paper offers a comprehensive review of the latest advancements in PPG-based AF detection, utilizing digital health and artificial intelligence (AI) solutions, within the timeframe spanning from July 2019 to December 2022. Through extensive exploration of scientific databases, we have identified 59 pertinent studies. Our comprehensive review encompasses an in-depth assessment of the statistical methodologies, traditional machine learning techniques, and deep learning approaches employed in these studies. In addition, we address the challenges encountered in the domain of PPG-based AF detection. Furthermore, we maintain a dedicated website to curate the latest research in this area, with regular updates on a regular basis.
摘要
AF（atrialfibrillation）是一种常见的心脏 arrhythmia，与 significativ health consequences associated， including elevated risk of ischemic stroke, heart disease, and increased mortality. Photoplethysmography (PPG) has emerged as a promising technology for continuous AF monitoring due to its cost-effectiveness and widespread integration into wearable devices. Our team previously conducted an exhaustive review of PPG-based AF detection before June 2019. However, since then, more advanced technologies have emerged in this field. This paper provides a comprehensive review of the latest advancements in PPG-based AF detection, utilizing digital health and artificial intelligence (AI) solutions, within the timeframe spanning from July 2019 to December 2022. Through extensive exploration of scientific databases, we have identified 59 pertinent studies. Our comprehensive review encompasses an in-depth assessment of the statistical methodologies, traditional machine learning techniques, and deep learning approaches employed in these studies. In addition, we address the challenges encountered in the domain of PPG-based AF detection. Furthermore, we maintain a dedicated website to curate the latest research in this area, with regular updates on a regular basis.