A decentralized control scheme can effectively solve the control problem of civil engineering structure vibration under earthquake. This paper takes a research into the decentralized control scheme of adjacent buildings when the earthquake happens. It combines overlapping decentralized control method and linear matrix inequality (LMI) with control algorithm and puts forward the overlapping decentralized control method. A simplified dynamical model of structural vibration control has been established considering the topology structural features of adjacent buildings. The control algorithm is applied into each dynamically different subsystems and can be also served as the decentralized controllers. Therefore, by contracting decentralized controllers to original state space, overlapping decentralized controllers are obtained. In this manner, the adjacent buildings’ structure model is analyzed in terms of simulation and calculation which provides a comprehensive insight into vibration control. The results show that the centralized control, the decentralized control, and the overlapping decentralized control, based on linear matrix inequality, can be nearly effective in cases above satisfactorily. Besides, it can also reduce the computational cost as well as increase the flexibility of controller design.

A special design is needed for an unmanned tracked vehicle (UTV) to meet the requirements of off-road environments and complex tasks. A loose surface is the main terrain for tracked vehicles in off-road driving. Slope steering is inevitable while driving in such conditions; hence, its performance is a major concern for tracked vehicles on loose terrain. This study investigates the slope steering performance of a tracked vehicle. An improved dynamic steering model is proposed when considering the shear stress-shear displacement relation of soil at the track-ground interface. The influence of ground characteristics on the slope steering performance of a tracked vehicle is illustrated. The track slip rate is adopted as an index to evaluate the influence of typical vehicle structure parameters on the slope steering performance of a tracked vehicle. This study provides technical support for the design and optimization of UTV.

Wireless sensor network is a key technology in Internet of Things. However, due to the large number of sensor nodes and limited security capability, aging nodes and malicious nodes increase. In order to detect the untrusted nodes in the network quickly and effectively and ensure the reliable operation of the network, this paper proposes a dynamic network security mechanism. Firstly, the direct trust value of the node is established based on its behavior in the regional information interaction. Then, the comprehensive trust value is calculated according to the trust recommendation value and energy evaluation value of other high-trust nodes. Finally, node reliability and management nodes are updated periodically. Malicious nodes are detected and isolated according to the credibility to ensure the dynamic, safe, and reliable operation of the network. Simulation results and analysis show that the node trust value calculated by this mechanism can reflect its credibility truly and accurately. In terms of reliable network operation, the mechanism can effectively detect malicious nodes, with higher detection rate, avoid the risk of malicious nodes as management nodes, reduce the energy consumption of nodes, and also play a defensive role in DOS attacks in wireless sensor networks.

Domain Name System (DNS) is a widely used infrastructure for remote control and batch management of IoT devices. As a critical Internet infrastructure, DNS is structured as a tree-like hierarchy with single root zone authority at the top, which puts the operation of DNS at risk from single point of failure. The current root zone management is lack of transparency and accountability, since only the root zone file is published as the final outcome of operations inside the root zone authority. Towards distributed root zone operation in DNS, this paper presents a blockchain-based root operation architecture—RootChain, composed of multiple root servers. On the basis of maintaining the single root authority for top-level domain (TLD), RootChain decentralizes TLD data publication by empowering delegated TLD authorities to publish authenticated data directly. The transparency and accountability of root zone operation are attained by smart-contracting the whole life cycle of TLD operation and logging all operations on the chain. RootChain is transparent to recursive/stub resolver and DNS/DNSSEC-compatible. A proof-of-concept prototype of RootChain has been implemented with Hyperledger Fabric and evaluated by experiments.

A novel two-phase method for two-dimensional (2D) direction-of-arrival (DOA) estimation with L-shaped array based on decoupled atomic norm minimization (DANM) is proposed in this paper. In the first phase, given the sample crosscorrelation matrix, the gridless DANM technique considering the noise and finite snapshots effects is employed to exploit the structure and sparse properties of the crosscorrelation matrix. The resulting DANM-based algorithm not only enables the crosscorrelation matrix reconstruction (CCMR) but also reconstructs the covariance matrix of the L-shaped array. Hence, sequentially, in the second phase, the conventional 2D DOA estimators for the L-shaped array can be adopted for the angle estimation. With appropriate 2D DOA estimators, the resulting proposed algorithms can not only achieve better performance but also detect more source number, compared with conventional crosscorrelation-based DOA estimators. Moreover, the proposed method, termed CCMR-DANM, not only has blind characteristic that it does not require the prior information of source numbers but also is more efficient than the existing CCMR-based counterparts. Numerical simulations demonstrate the effectiveness and outperformance of the proposed method.

Ultrasound-targeted microbubble destruction (UTMD) has been proven as an effective technique to assist drugs to cross the vascular wall and cell membrane. This study was aimed at evaluating the synergistic antiangiogenic and growth-inhibiting effects of apatinib (APA) and UTMD on the triple negative breast cancer (TNBC). The TNBC xenograft model was established in nude mice ( ) which were then randomly divided into the APA plus UTMD (APA-U) group, UTMD group, APA group, and model control (M) group ( per group). Corresponding treatment was done once daily for 14 consecutive days. The general condition and body weight of tumor-bearing nude mice were monitored. Routine blood test and detection of liver and kidney function were done after treatments. The tumor size and microcirculation were examined by two-dimensional ultrasonography (2DUS) and contrast-enhanced ultrasonography (CEUS), respectively. Then, the tumor tissues were harvested for the detection of vascular endothelial growth factor (VEGF) by immunohistochemistry and for CD31-PAS double staining to assess microvessel density (MVD) and heterogeneous vascular positivity rate. After treatments, the tumor growth and angiogenesis were significantly inhibited in the APA group and the APA-U group, and these effects were more obvious in the APA-U group. The tumor volume, CEUS parameters, VEGF expression, and MVD in the APA-U group were significantly lower than those in the APA group ( ), while there were no marked differences in the heterogeneous vascular positivity rate, body weight, and blood parameters between the two groups ( ). In the UTMD group, the tumor growth and angiogenesis were not significantly inhibited, and all the parameters were similar to those in the M group ( ). During the experiment, all mice survived and generally had good condition. In conclusion, APA combined with UTMD may exert synergistic antiangiogenic and growth-inhibiting effects on the TNBC and not increase the heterogeneous vasculature and the severity of APA-related systemic side effects.