A key challenge in federated learning applications is the statistical heterogeneity of local datasets. Clustered federated learning addresses this challenge by identifying clusters of local datasets that are approxima...
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ISBN:
(纸本)9789464593617;9798331519773
A key challenge in federated learning applications is the statistical heterogeneity of local datasets. Clustered federated learning addresses this challenge by identifying clusters of local datasets that are approximately homogeneous. One recent approach to clustered federated learning is generalized total variation minimization (GTVMin). This approach requires a similarity graph which can be obtained by domain expertise or in a data-driven fashion via graph learning techniques. Under a widely applicable clustering assumption, we derive an upper bound the deviation between GTVMin solutions and their cluster-wise averages.
This article considers a category of constrained convex optimization problems over multiagent networks. The networked agents aim at collaboratively minimizing the sum of all locally known objective functions over a co...
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This article considers a category of constrained convex optimization problems over multiagent networks. The networked agents aim at collaboratively minimizing the sum of all locally known objective functions over a common convex set. Each agent possesses only its local convex function and its state is constrained to a privately known convex set. A novel distributed algorithm is proposed over time-varying unbalanced directed networks based on epigraph form of the original optimization problem and consensus theory. By incorporating the random sleep scheme, the proposed algorithm allows each agent to independently and randomly decide whether to calculate subgradient and take projection at each iteration, which alleviates the cost of subgradient observation. Besides, it neither resorts to doubly stochastic weight matrices (but only row-stochastic) nor the information of the graph sequence to execute. The convergence of the algorithm is explicitly analyzed under conditions that the sequence of time-varying directed graphs is uniformly jointly strongly connected and the subgradients of all local objective functions are bounded over a convex set. The optimization algorithm ensures zero-gap on the expected distance between the estimated value of each agent and the exact optimal solution. The two simulation cases are presented to demonstrate the practicability of the algorithm and correctness of the obtained theoretical results.
distributed Bayesian inference provides a full quantification of uncertainty offering numerous advantages over point estimates that autonomous sensor networks are able to exploit. However, fully-decentralized Bayesian...
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distributed Bayesian inference provides a full quantification of uncertainty offering numerous advantages over point estimates that autonomous sensor networks are able to exploit. However, fully-decentralized Bayesian inference often requires large communication overheads and low network latency, resources that are not typically available in practical applications. In this paper, we propose a decentralized Bayesian inference approach based on stochastic gradient Langevin dynamics, which produces full posterior distributions at each of the nodes with significantly lower communication overhead. We provide analytical results on convergence of the proposed distributed algorithm to the centralized posterior, under typical network constraints. We also provide extensive simulation results to demonstrate the validity of the proposed approach.
Thanks to billions of users in online social networks (OSNs), viral marketing becomes one of the most effective promotion channels for various new products or campaigns. Influence maximization is a classic problem in ...
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ISBN:
(数字)9781665408837
ISBN:
(纸本)9781665408837
Thanks to billions of users in online social networks (OSNs), viral marketing becomes one of the most effective promotion channels for various new products or campaigns. Influence maximization is a classic problem in viral marketing, which has been extensively studied in the past two decades. Existing algorithms for influence maximization, however, mostly focus on single machine processing. To address the influence maximization problem on a massive scale, we design distributed algorithms via a cluster of machines, which can effectively speed up the computation while maintaining the state-of-the-art (1 - 1/e-epsilon)-approximation guarantee. Our distributed algorithms consist of two building blocks: (i) distributed reverse influence sampling, and (ii) element-distributed maximum coverage. We carry out extensive experiments on real datasets with millions of nodes and billions of edges to demonstrate the scalability of our distributed algorithms for both influence maximization and maximum coverage. In particular, our distributed algorithms accelerate the state-of-the-art IMM algorithm by 31x-56x times using a machine with 64 cores.
For the composite function composed of L-smooth general convex functions and non-smooth convex functions,a new accelerated distributed composite Nesterov gradient descent algorithm(Acc-DCNGD-NSC) is proposed in this...
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ISBN:
(数字)9789887581536
ISBN:
(纸本)9781665482561
For the composite function composed of L-smooth general convex functions and non-smooth convex functions,a new accelerated distributed composite Nesterov gradient descent algorithm(Acc-DCNGD-NSC) is proposed in this *** algorithm can be applied to smooth convex optimization problems and composite convex optimization *** applying Nesterov acceleration techniques and a new gradient estimation scheme to the distributed proximal gradient algorithm,Acc-DCNGD-NSC is able to converge at a sub-linear rate of O(1/t)to global optimal solution.
Assigning items to owners is a common problem found in various real-world applications, for example, audience-channel matching in marketing campaigns, borrower-lender matching in loan management, and shopper-merchant ...
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ISBN:
(纸本)9781450392365
Assigning items to owners is a common problem found in various real-world applications, for example, audience-channel matching in marketing campaigns, borrower-lender matching in loan management, and shopper-merchant matching in e-commerce. Given an objective and multiple constraints, an assignment problem can be formulated as a constrained optimization problem. Such assignment problems are usually NP-hard [21], so when the number of items or the number of owners is large, solving for exact solutions becomes challenging. In this paper, we are interested in solving constrained assignment problems with hundreds of millions of items. Thus, with just tens of owners, the number of decision variables is at billion-scale. This scale is usually seen in the internet industry, which makes decisions for large groups of users. We relax the possible integer constraint, and formulate a general optimization problem that covers commonly seen assignment problems. Its objective function is convex. Its constraints are either linear, or convex and separable by items. We study to solve our generalized assignment problems in the Bregman Alternating Direction Method of Multipliers (BADMM) framework where we exploit Bregman divergence to transform the Augmented Lagrangian into a separable form, and solve many subproblems in parallel. The entire solution can thus be implemented using a MapReduce-style distributed computation framework. We present experiment results on both synthetic and real-world datasets to verify its accuracy and scalability.
For more than three decades, distributed systems have been described and analyzed using topological tools, primarily using two techniques: protocol complexes and directed algebraic topology. In both cases, the conside...
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Detecting and handling network partitions is a fundamental requirement of distributed systems. Although existing partition detection methods in arbitrary graphs tolerate unreliable networks, they either assume that al...
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ISBN:
(纸本)9798350386066;9798350386059
Detecting and handling network partitions is a fundamental requirement of distributed systems. Although existing partition detection methods in arbitrary graphs tolerate unreliable networks, they either assume that all nodes are correct or that a limited number of nodes might crash. In particular, Byzantine behaviors are out of the scope of these algorithms despite Byzantine fault tolerance being an active research topic for important problems such as consensus. Moreover, Byzantine-tolerant protocols, such as broadcast or consensus, always rely on the assumption of connected networks. This paper addresses the problem of detecting partition in Byzantine networks (without connectivity assumption). We present a novel algorithm, which we call NECTAR, that safely detects partitioned and possibly partitionable networks and prove its correctness. NECTAR allows all correct nodes to detect whether a network could suffer from Byzantine nodes. We evaluate NECTAR's performance and compare it to two existing baselines using up to 100 nodes running real code, on various realistic topologies. Our results confirm that NECTAR maintains a 100% accuracy while the accuracy of the various existing baselines decreases by at least 40% as soon as one participant is Byzantine. Although NECTAR's network cost increases with the number of nodes and decreases with the network's diameter, it does not go above around 500KB in the worst cases.
In this letter, the social cost minimization problem with coupled equality constraints is studied, where the agents endeavor to collaboratively minimize the sum of all local cost functions, and each local cost functio...
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In this letter, the social cost minimization problem with coupled equality constraints is studied, where the agents endeavor to collaboratively minimize the sum of all local cost functions, and each local cost function depends on a global decision variable consisting of the decisions of all participants. In a setting where only partial information about one's own decisions and cost function is available, the first single-time scale predefined-time distributed algorithm based on the time-based-generator scheme is designed to tackle the problem. With the help of the Lyapunov stability theory, it is demonstrated that the algorithm can converge to the optimal solution in an arbitrarily specified time independent of the initial state and control parameters. Finally, the effectiveness of the proposed algorithm is verified by numerical simulations.
In this paper, we address the average consensus problem of multi-agent systems for possibly unbalanced and delay-prone networks with directional information flow. We propose a linear distributed algorithm (referred to...
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ISBN:
(纸本)9798331540920;9783907144107
In this paper, we address the average consensus problem of multi-agent systems for possibly unbalanced and delay-prone networks with directional information flow. We propose a linear distributed algorithm (referred to as RP-PAC) that handles asynchronous updates and time-varying heterogeneous information delays. Our proposed distributed algorithm utilizes a surplus-consensus mechanism and information regarding the number of incoming and outgoing links to guarantee state averaging, despite the imbalanced and delayed information flow in directional networks. The convergence of the RPPAC algorithm is examined using key properties of the backward product of time-varying matrices that correspond to different snapshots of the directional augmented network.
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