联合学习已被引入新的机器学习范式，以增强本地设备的使用。在服务器级别，FL定期聚集在分布式客户端上本地学习的模型，以获得更通用的模型。这样，没有通过网络发送私人数据，并且降低了通信成本。但是，当前的解决方案依赖于客户端的大量存储数据的可用性，以微调服务器发送的模型。这种设置在移动普遍计算中不现实，在该计算中必须保持数据存储较低，并且数据特征（分布）可能会发生巨大变化。为了解释这种可变性，解决方案是使用客户定期收集的数据来逐步调整接收到的模型。但是这种天真的方法使客户面临着灾难性遗忘的众所周知的问题。本文的目的是在智能手机的移动人类活动识别环境中证明这个问题。

联合学习已被引入新的机器学习范式，以增强本地设备的使用。在服务器级别，FL定期聚集在分布式客户端上本地学习的模型，以获得更通用的模型。当前的解决方案依赖于客户端的大量存储数据的可用性，以微调服务器发送的模型。这种设置在移动普遍计算中不现实，在该计算中必须保持数据存储较低，并且数据特征可能会发生巨大变化。为了解释这种可变性，解决方案是使用客户定期收集的数据来逐步调整接收到的模型。但是这种天真的方法使客户面临着灾难性遗忘的众所周知的问题。为了解决这个问题，我们定义了一种联合的持续学习方法，该方法主要基于蒸馏。我们的方法允许更好地利用资源，从而消除了在新数据到达时从头开始重新审阅的需求，并通过限制存储的数据量来减少内存使用量。该提案已在人类活动识别（HAR）领域进行了评估，并已证明可以有效地降低灾难性的遗忘效果。

联合学习是一种新的机器学习范式，涉及独立设备上的分布式模型学习。联合学习的众多优点之一是，培训数据留在设备上（例如智能手机），并且仅与集中式服务器共享学习的模型。在监督学习的情况下，标签被委托给客户。但是，对于许多任务，例如人类活动识别，获取此类标签可能非常昂贵且容易出错。因此，大量数据仍然没有标记和未能探索。主要关注监督学习的大多数现有联合学习方法主要忽略了这些未标记的数据。此外，目前尚不清楚标准联合学习方法是否适合于自制学习。处理该问题的少数研究局限于同质数据集的有利状况。这项工作为在现实的环境中对联合学习的参考评估奠定了基础。我们表明，标准的轻型自动编码器和标准联合平均值无法通过几个现实的异质数据集学习对人类活动识别的强大表示形式。这些发现倡导在联合自我监督学习方面进行更深入的研究工作，以利用移动设备上存在的异质无标记数据的质量。

Deep Neural Networks (DNNs) have been ubiquitously adopted in internet of things and are becoming an integral of our daily life. When tackling the evolving learning tasks in real world, such as classifying different types of objects, DNNs face the challenge to continually retrain themselves according to the tasks on different edge devices. Federated continual learning is a promising technique that offers partial solutions but yet to overcome the following difficulties: the significant accuracy loss due to the limited on-device processing, the negative knowledge transfer caused by the limited communication of non-IID data, and the limited scalability on the tasks and edge devices. In this paper, we propose FedKNOW, an accurate and scalable federated continual learning framework, via a novel concept of signature task knowledge. FedKNOW is a client side solution that continuously extracts and integrates the knowledge of signature tasks which are highly influenced by the current task. Each client of FedKNOW is composed of a knowledge extractor, a gradient restorer and, most importantly, a gradient integrator. Upon training for a new task, the gradient integrator ensures the prevention of catastrophic forgetting and mitigation of negative knowledge transfer by effectively combining signature tasks identified from the past local tasks and other clients' current tasks through the global model. We implement FedKNOW in PyTorch and extensively evaluate it against state-of-the-art techniques using popular federated continual learning benchmarks. Extensive evaluation results on heterogeneous edge devices show that FedKNOW improves model accuracy by 63.24% without increasing model training time, reduces communication cost by 34.28%, and achieves more improvements under difficult scenarios such as large numbers of tasks or clients, and training different complex networks.

联合学习是一种在不违反隐私限制的情况下对分布式数据集进行统计模型培训统计模型的最新方法。通过共享模型而不是客户和服务器之间的数据来保留数据位置原则。这带来了许多优势，但也带来了新的挑战。在本报告中，我们探讨了这个新的研究领域，并执行了几项实验，以加深我们对这些挑战的理解以及不同的问题设置如何影响最终模型的性能。最后，我们为这些挑战之一提供了一种新颖的方法，并将其与文献中的其他方法进行了比较。

联合学习是一种新颖的框架，允许多个设备或机构在保留其私有数据时协同地培训机器学习模型。这种分散的方法易于遭受数据统计异质性的后果，无论是在不同的实体还是随着时间的推移，这可能导致缺乏会聚。为避免此类问题，在过去几年中提出了不同的方法。然而，数据可能在许多不同的方式中是异构的，并且当前的建议并不总是确定他们正在考虑的异质性的那种。在这项工作中，我们正式地分类数据统计异质性，并审查能够面对它的最显着的学习策略。与此同时，我们介绍了其他机器学习框架的方法，例如持续学习，也处理数据异质性，并且可以很容易地适应联邦学习设置。

Federated Learning (FL), as a rapidly evolving privacy-preserving collaborative machine learning paradigm, is a promising approach to enable edge intelligence in the emerging Industrial Metaverse. Even though many successful use cases have proved the feasibility of FL in theory, in the industrial practice of Metaverse, the problems of non-independent and identically distributed (non-i.i.d.) data, learning forgetting caused by streaming industrial data, and scarce communication bandwidth remain key barriers to realize practical FL. Facing the above three challenges simultaneously, this paper presents a high-performance and efficient system named HFEDMS for incorporating practical FL into Industrial Metaverse. HFEDMS reduces data heterogeneity through dynamic grouping and training mode conversion (Dynamic Sequential-to-Parallel Training, STP). Then, it compensates for the forgotten knowledge by fusing compressed historical data semantics and calibrates classifier parameters (Semantic Compression and Compensation, SCC). Finally, the network parameters of the feature extractor and classifier are synchronized in different frequencies (Layer-wiseAlternative Synchronization Protocol, LASP) to reduce communication costs. These techniques make FL more adaptable to the heterogeneous streaming data continuously generated by industrial equipment, and are also more efficient in communication than traditional methods (e.g., Federated Averaging). Extensive experiments have been conducted on the streamed non-i.i.d. FEMNIST dataset using 368 simulated devices. Numerical results show that HFEDMS improves the classification accuracy by at least 6.4% compared with 8 benchmarks and saves both the overall runtime and transfer bytes by up to 98%, proving its superiority in precision and efficiency.

In federated learning, a strong global model is collaboratively learned by aggregating clients' locally trained models. Although this precludes the need to access clients' data directly, the global model's convergence often suffers from data heterogeneity. This study starts from an analogy to continual learning and suggests that forgetting could be the bottleneck of federated learning. We observe that the global model forgets the knowledge from previous rounds, and the local training induces forgetting the knowledge outside of the local distribution. Based on our findings, we hypothesize that tackling down forgetting will relieve the data heterogeneity problem. To this end, we propose a novel and effective algorithm, Federated Not-True Distillation (FedNTD), which preserves the global perspective on locally available data only for the not-true classes. In the experiments, FedNTD shows state-of-the-art performance on various setups without compromising data privacy or incurring additional communication costs.

Federated Learning (FL) enables the training of Deep Learning models without centrally collecting possibly sensitive raw data. This paves the way for stronger privacy guarantees when building predictive models. The most used algorithms for FL are parameter-averaging based schemes (e.g., Federated Averaging) that, however, have well known limits: (i) Clients must implement the same model architecture; (ii) Transmitting model weights and model updates implies high communication cost, which scales up with the number of model parameters; (iii) In presence of non-IID data distributions, parameter-averaging aggregation schemes perform poorly due to client model drifts. Federated adaptations of regular Knowledge Distillation (KD) can solve and/or mitigate the weaknesses of parameter-averaging FL algorithms while possibly introducing other trade-offs. In this article, we provide a review of KD-based algorithms tailored for specific FL issues.

随着对用户数据隐私的越来越关注，联合学习（FL）已被开发为在边缘设备上训练机器学习模型的独特培训范式，而无需访问敏感数据。传统的FL和现有方法直接在云服务器的同一型号和培训设备的所有边缘上采用聚合方法。尽管这些方法保护了数据隐私，但它们不能具有模型异质性，甚至忽略了异质的计算能力，也可以忽略陡峭的沟通成本。在本文中，我们目的是将资源感知的FL汇总为从边缘模型中提取的本地知识的集合，而不是汇总每个本地模型的权重，然后将其蒸馏成一个强大的全局知识，作为服务器模型通过知识蒸馏。通过深入的相互学习，将本地模型和全球知识提取到很小的知识网络中。这种知识提取使Edge客户端可以部署资源感知模型并执行多模型知识融合，同时保持沟通效率和模型异质性。经验结果表明，在异质数据和模型中的通信成本和概括性能方面，我们的方法比现有的FL算法有了显着改善。我们的方法将VGG-11的沟通成本降低了102美元$ \ times $和Resnet-32，当培训Resnet-20作为知识网络时，最多可达30美元$ \ times $。

随着对数据隐私和数据量迅速增加的越来越关注，联邦学习（FL）已成为重要的学习范式。但是，在FL环境中共同学习深层神经网络模型被证明是一项非平凡的任务，因为与神经网络相关的复杂性，例如跨客户的各种体系结构，神经元的置换不变性以及非线性的存在每一层的转换。这项工作介绍了一个新颖的联合异质神经网络（FEDHENN）框架，该框架允许每个客户构建个性化模型，而无需在跨客户范围内实施共同的架构。这使每个客户都可以优化本地数据并计算约束，同时仍能从其他（可能更强大）客户端的学习中受益。 Fedhenn的关键思想是使用从同行客户端获得的实例级表示，以指导每个客户的同时培训。广泛的实验结果表明，Fedhenn框架能够在跨客户的同质和异质体系结构的设置中学习更好地表现客户的模型。

Federated Learning (FL) allows training machine learning models in privacy-constrained scenarios by enabling the cooperation of edge devices without requiring local data sharing. This approach raises several challenges due to the different statistical distribution of the local datasets and the clients' computational heterogeneity. In particular, the presence of highly non-i.i.d. data severely impairs both the performance of the trained neural network and its convergence rate, increasing the number of communication rounds requested to reach a performance comparable to that of the centralized scenario. As a solution, we propose FedSeq, a novel framework leveraging the sequential training of subgroups of heterogeneous clients, i.e. superclients, to emulate the centralized paradigm in a privacy-compliant way. Given a fixed budget of communication rounds, we show that FedSeq outperforms or match several state-of-the-art federated algorithms in terms of final performance and speed of convergence. Finally, our method can be easily integrated with other approaches available in the literature. Empirical results show that combining existing algorithms with FedSeq further improves its final performance and convergence speed. We test our method on CIFAR-10 and CIFAR-100 and prove its effectiveness in both i.i.d. and non-i.i.d. scenarios.

Continuous behavioural authentication methods add a unique layer of security by allowing individuals to verify their unique identity when accessing a device. Maintaining session authenticity is now feasible by monitoring users' behaviour while interacting with a mobile or Internet of Things (IoT) device, making credential theft and session hijacking ineffective. Such a technique is made possible by integrating the power of artificial intelligence and Machine Learning (ML). Most of the literature focuses on training machine learning for the user by transmitting their data to an external server, subject to private user data exposure to threats. In this paper, we propose a novel Federated Learning (FL) approach that protects the anonymity of user data and maintains the security of his data. We present a warmup approach that provides a significant accuracy increase. In addition, we leverage the transfer learning technique based on feature extraction to boost the models' performance. Our extensive experiments based on four datasets: MNIST, FEMNIST, CIFAR-10 and UMDAA-02-FD, show a significant increase in user authentication accuracy while maintaining user privacy and data security.

联合学习（FL）可以对机器学习模型进行分布式培训，同时将个人数据保存在用户设备上。尽管我们目睹了FL在移动传感领域的越来越多的应用，例如人类活动识别（HAR），但在多设备环境（MDE）的背景下，尚未对FL进行研究，其中每个用户都拥有多个数据生产设备。随着移动设备和可穿戴设备的扩散，MDE在Ubicomp设置中越来越受欢迎，因此需要对其中的FL进行研究。 MDE中的FL的特征是在客户和设备异质性的存在中并不复杂，并不是独立的，并且在客户端之间并非独立分布（非IID）。此外，确保在MDE中有效利用佛罗里达州客户的系统资源仍然是一个重要的挑战。在本文中，我们提出了以用户为中心的FL培训方法来应对MDE中的统计和系统异质性，并在设备之间引起推理性能的一致性。火焰功能（i）以用户为中心的FL培训，利用同一用户的设备之间的时间对齐； （ii）准确性和效率感知设备的选择； （iii）对设备的个性化模型。我们还提出了具有现实的能量流量和网络带宽配置文件的FL评估测试，以及一种基于类的新型数据分配方案，以将现有HAR数据集扩展到联合设置。我们在三个多设备HAR数据集上的实验结果表明，火焰的表现优于各种基准，F1得分高4.3-25.8％，能源效率提高1.02-2.86倍，并高达2.06倍的收敛速度，以通过FL的公平分布来获得目标准确性工作量。

With the booming deployment of Internet of Things, health monitoring applications have gradually prospered. Within the recent COVID-19 pandemic situation, interest in permanent remote health monitoring solutions has raised, targeting to reduce contact and preserve the limited medical resources. Among the technological methods to realize efficient remote health monitoring, federated learning (FL) has drawn particular attention due to its robustness in preserving data privacy. However, FL can yield to high communication costs, due to frequent transmissions between the FL server and clients. To tackle this problem, we propose in this paper a communication-efficient federated learning (CEFL) framework that involves clients clustering and transfer learning. First, we propose to group clients through the calculation of similarity factors, based on the neural networks characteristics. Then, a representative client in each cluster is selected to be the leader of the cluster. Differently from the conventional FL, our method performs FL training only among the cluster leaders. Subsequently, transfer learning is adopted by the leader to update its cluster members with the trained FL model. Finally, each member fine-tunes the received model with its own data. To further reduce the communication costs, we opt for a partial-layer FL aggregation approach. This method suggests partially updating the neural network model rather than fully. Through experiments, we show that CEFL can save up to to 98.45% in communication costs while conceding less than 3% in accuracy loss, when compared to the conventional FL. Finally, CEFL demonstrates a high accuracy for clients with small or unbalanced datasets.

高效联合学习是在边缘设备上培训和部署AI模型的关键挑战之一。然而，在联合学习中维护数据隐私提出了几种挑战，包括数据异质性，昂贵的通信成本和有限的资源。在本文中，我们通过（a）通过基于本地客户端的深度增强学习引入突出参数选择代理的上述问题，并在中央服务器上聚合所选择的突出参数，（b）分割正常的深度学习模型〜 （例如，CNNS）作为共享编码器和本地预测器，并通过联合学习训练共享编码器，同时通过本地自定义预测器将其知识传送到非IID客户端。所提出的方法（a）显着降低了联合学习的通信开销，并加速了模型推断，而方法（b）则在联合学习中解决数据异质性问题。此外，我们利用梯度控制机制来校正客户之间的梯度异质性。这使得训练过程更稳定并更快地收敛。实验表明，我们的方法产生了稳定的训练过程，并与最先进的方法相比实现了显着的结果。在培训VGG-11时，我们的方法明显降低了通信成本最高108 GB，并在培训Reset-20时需要7.6美元的通信开销，同时通过减少高达39.7 \％$ 39.7 \％$ vgg- 11.

联合学习（FL）根据多个本地客户端协同聚合共享全球模型，同时保持培训数据分散以保护数据隐私。但是，标准的FL方法忽略了嘈杂的客户问题，这可能会损害聚合模型的整体性能。在本文中，我们首先分析了嘈杂的客户声明，然后用不同的噪声分布模型噪声客户端（例如，Bernoulli和截断的高斯分布）。要使用嘈杂的客户，我们提出了一个简单但有效的FL框架，名为联邦嘈杂的客户学习（FED-NCL），它是一个即插即用算法，并包含两个主要组件：动态的数据质量测量（DQM）量化每个参与客户端的数据质量，以及噪声鲁棒聚合（NRA），通过共同考虑本地训练数据和每个客户端的数据质量来自适应地聚合每个客户端的本地模型。我们的FED-NCL可以轻松应用于任何标准的流行流以处理嘈杂的客户端问题。各种数据集的实验结果表明，我们的算法提高了具有嘈杂客户端的不同现实系统的性能。

In this paper, we increase the availability and integration of devices in the learning process to enhance the convergence of federated learning (FL) models. To address the issue of having all the data in one location, federated learning, which maintains the ability to learn over decentralized data sets, combines privacy and technology. Until the model converges, the server combines the updated weights obtained from each dataset over a number of rounds. The majority of the literature suggested client selection techniques to accelerate convergence and boost accuracy. However, none of the existing proposals have focused on the flexibility to deploy and select clients as needed, wherever and whenever that may be. Due to the extremely dynamic surroundings, some devices are actually not available to serve as clients in FL, which affects the availability of data for learning and the applicability of the existing solution for client selection. In this paper, we address the aforementioned limitations by introducing an On-Demand-FL, a client deployment approach for FL, offering more volume and heterogeneity of data in the learning process. We make use of the containerization technology such as Docker to build efficient environments using IoT and mobile devices serving as volunteers. Furthermore, Kubernetes is used for orchestration. The Genetic algorithm (GA) is used to solve the multi-objective optimization problem due to its evolutionary strategy. The performed experiments using the Mobile Data Challenge (MDC) dataset and the Localfed framework illustrate the relevance of the proposed approach and the efficiency of the on-the-fly deployment of clients whenever and wherever needed with less discarded rounds and more available data.

培训具有分布式数据的集中模型的联合学习工作流程越来越受欢迎。但是，直到最近，这是贡献具有类似计算能力的客户的领域。在边缘生成和处理的快速扩展IOT空间和数据正在鼓励更多地努力扩展联合学习以包括异构系统。以前的方法将较小模型分发给客户端，以蒸馏出本地数据的特性。但是，在客户端的大量本地数据仍然存在培训的问题。我们建议减少培训全球模型所需的本地数据量。我们通过将模型分成通用特征提取的下部和对本地数据的特性更敏感的上部来执行此操作。我们通过聚类本地数据并仅选择用于培训的最具代表性样本来培训上部所需的数据量。我们的实验表明，小于1％的本地数据可以通过我们的缝隙网络方法将客户数据的特征传输到全球模型。这些初步结果令人鼓舞的是，在计算资源有限的设备上缩短数据，持续减少数据，但这阻碍了对全球模型有助于贡献的关键信息。

联合学习是一种数据解散隐私化技术，用于以安全的方式执行机器或深度学习。在本文中，我们介绍了有关联合学习的理论方面客户次数有所不同的用例。具体而言，使用从开放数据存储库中获得的胸部X射线图像提出了医学图像分析的用例。除了与隐私相关的优势外，还将研究预测的改进（就曲线下的准确性和面积而言）和减少执行时间（集中式方法）。将从培训数据中模拟不同的客户，以不平衡的方式选择，即，他们并非都有相同数量的数据。考虑三个或十个客户之间的结果与集中案件相比。间歇性客户将分析两种遵循方法，就像在实际情况下，某些客户可能会离开培训，一些新的新方法可能会进入培训。根据准确性，曲线下的区域和执行时间的结果，结果的结果的演变显示为原始数据被划分的客户次数。最后，提出了该领域的改进和未来工作。