This article investigates the distributed aggregation optimization problem in multiagent systems (MASs), with a particular focus on addressing the aggregation effect commonly encountered in modern engineering and technological applications. In such scenarios, the local objective function of an agent depends not only on its own decision variables but also interacts with the decision variables of other agents, resulting in complex coupling relationships. To solve these challenges while ensuring that the optimization variables satisfy the coupled inequality constraints, this article introduces a novel framework called distributed aggregative parameter projection (DAPP). Specifically, the proposed distributed protocol is based on an improved parameter projection, including two direction updates, which minimizes the cost function and keeps the search direction obeying the inequality at each iteration. In addition, the linear convergence performance of the proposed scheme over the undirected and connected graph is ensured by rigorous theoretical proof with mild assumptions. Finally, simulation results demonstrate the superior performance of DAPP with smaller global function and faster convergence speed in comparison to the existing method.
In this article, we propose a self-triggered distributionally robust model predictive control algorithm for linear discrete systems with state chance constraints and unbounded stochastic disturbances. Assuming that only the first and second moments of the disturbance are accessible, we transform the objective function into a compact quadratic form and reformulate the state chance constraints into linear inequalities, which is more tractable when solving. In order to reduce communication and sampling times of the system, we propose a self-triggered update scheme, in which the state sampling and the control input sequence are updated when the control performance predicted based on the current sampling exceeds that of the periodic sampling scheme. We demonstrate that the optimization problem in the proposed self-triggered model predictive control (MPC) method is recursively feasible and stable. Numerical simulation results verify the effectiveness of the proposed algorithm.
Real-world complex systems usually share structural characteristics such as the small-world property, power-law distributions, and community structure. Multidomain evolutionary optimization (MDEO) leverages these commonalities to search for optimal solutions in multiple domains simultaneously. However, it still faces challenges in achieving effective cooperation when the networks involved are of highly imbalanced sizes. To address this issue, we propose the harmonized MDEO (HMDEO), in which two graph coarsening strategies are developed to jointly coarsen the large network to a fine level, acting as the bridge between the large network and the small network for knowledge exchange. Following that, we propose a bidirectional optimization framework incorporating two cases: large-to-small and small-to-large, allowing solutions optimized in one domain to be seamlessly transferred to another domain of varied scales. To enhance applicability, we also tailor the measurement of network similarity and the network alignment strategy targeted to imbalanced-size scenarios. The effectiveness of HMDEO is demonstrated through experiments on several pairs of networks of differing scales, where HMDEO outperforms other optimization approaches in addressing adversarial edge perturbation against community detection in complex systems.
This article studies the global asymptotic neural network (NN) tracking problem for full-state error constrained spacecraft attitude systems with actuator faults, inertia uncertainties, and external disturbances. In the literature, most existing NN control schemes can only achieve semiglobally bounded stability since the approximation capability of NNs is confined to a compact domain called the approximation domain. Differently, an attitude tracking control strategy in conjunction with a modified smooth switching mechanism is proposed to ensure the global asymptotic stability. Specifically, an adaptive NN controller is developed within the approximation domain to address unknown nonlinearities, and a robust controller is activated outside the approximation domain to drive back the system states. With the proposed design, both attitude and angular velocity errors (collectively defined as the full-state errors) are rigorously proven to globally asymptotically converge to zero. Moreover, the full-state errors are preserved within the unified prescribed performance constraints, which are uniform with respect to any initial conditions, thereby eliminating the requirement for offline computation of the performance boundary. In addition, the undesirable feasibility conditions on virtual control laws are completely eliminated. Theoretical analysis and numerical simulations validate the effectiveness of the proposed method.
High-dimensional and incomplete (HDI) data commonly arise in many complex application scenarios, such as bioinformatics and recommender systems. Deep neural networks (DNNs) exhibit cutting-edge performance in representing HDI data due to their formidable capacity for nonlinear learning. However, previous research primarily concentrates on single-metric-focused models utilizing fixed and exclusive $L_{2}$ -norm-based strategies for both loss and regularize terms. Such strategies limit the model’s ability to effectively learn from diverse and heterogeneous HDI data. Recognizing this limitation, this article presents the multimetric autoencoder (MMA) with the following twofold ideas: 1) utilizing multiple $L_{p}$ -norms to create four distinct autoencoders, each defining a unique metric representation space with diverse regularize and loss characteristics; 2) integrating these four diverse autoencoders by using a customized, self-adjusting weighting strategy. This innovative approach enhances the model’s capacity to handle heterogeneous and inclusive HDI data effectively, addressing the limitations of previous studies. The theoretical analysis supports the effectiveness of the MMA in harnessing the benefits of diverse multimetric spaces. In the experiments, the MMA is evaluated on six real HDI datasets. The experimental results reveal that the MMA outperforms seven contemporary models in effectively representing HDI data.
