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Traffic-induced moving force identification (MFI) is a typical inverse problem in the field of bridge structural health monitoring. Lots of regularization-based methods have been proposed for MFI. However, the MFI accuracy obtained from the existing methods is low when the moving forces enter into and exit a bridge deck due to low sensitivity of structural responses to the forces at these zones. To overcome this shortcoming, a novel moving average Tikhonov regularization method is proposed for MFI by combining with the moving average concepts. Firstly, the bridge-vehicle interaction moving force is assumed as a discrete finite signal with stable average value (DFS-SAV). Secondly, the reasonable signal feature of DFS-SAV is quantified and introduced for improving the penalty function (||x|| 2 2 ) defined in the classical Tikhonov regularization. Then, a feasible two-step strategy is proposed for selecting regularization parameter and balance coefficient defined in the improved penalty function. Finally, both numerical simulations on a simply-supported beam and laboratory experiments on a hollow tube beam are performed for assessing the accuracy and the feasibility of the proposed method. The illustrated results show that the moving forces can be accurately identified with a strong robustness. Some related issues, such as selection of moving window length, effect of different penalty functions, and effect of different car speeds, are discussed as well.

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The visible light communication (VLC) system using light-emitting diodes (LEDs) is able to achieve a higher transmission rate compared with the traditional radio frequency network. However, the throughput and average spectral efficiency (ASE) of the system may decrease due to the inter-cell interference and the inter-user interference, particularly for the indoor environment, where the LEDs are densely deployed in the case of multiple users. To suppress such interference, we introduce innovatively the improved tabu search (TS) algorithm into the frequency reuse in the multiuser VLC networks. We propose a bidirectional double tabu list strategy to avoid getting trapped in the situation of the local optimum. In addition, we design the evaluation function and aspiration criterion of the algorithm. We employ the improved TS algorithm to find the optical dynamic frequency reuse scheme by combining the interference graph. The interference graph is used to determine the interference relationships and to construct the solutions to the algorithm. The simulation results show that our proposed scheme effectively improves the throughput and the ASE of the system without lowering the fairness performance, especially in the scenario of numerous users.

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