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This paper investigates the finite-time consensus tracking problem for a group of quadrotor aircraft with a leader-follower structure. Based on finite-time algorithms, the finitetime position controller and attitude controller are designed respectively in this note. Based on homogenous system theory and Lyapunov theory, the finite-time stability of the closed-loop systems is given and it is shown...
The distributed synchronization control problem of multiple quadrotor aircraft in the form of leader-follower structure is considered in this paper. Based on the method of backstepping design, a novel distributed consensus control algorithm is proposed. Firstly, for the position control subsystem, by Proportional-Differential control and the theory of communication topology graph, a consensus control...
Network equivalence is useful for electrical market analysis in large power networks. Generation shift factors (GSF)-based bus clustering methods have been used for network equivalence to analyze the impact of changes in transactions between operating areas or congestion zones on transmission line flows. However, GSFs are sensitive to the location change of slack generator. Equivalent networks based...
Traditional research on typhoon disaster mainly take the overall wind assessment or the path prediction of typhoon into consideration. In the view of the change of the global climate and the unpredictable conditions in typhoon forecast, the existing methods occur limitations in finding a way to do the typhoon disaster assessment in the different and concrete region of typhoon area. In this paper,...
In this study, a steady and comparatively smooth Ni-P coating on the surface of diamond/Al composite substrate was fabricated by electroless plating, which can outstandingly improve solderability of the composite. By controlling the deposition time, we obtained the growth curve of the Ni-P coating, and as a result we can adjust the thickness of the coating. The solderability was tested by soldering...
Location-Based Service (LBS) becomes increasingly important for our daily life. However, the localization information in the air is vulnerable to various attacks, which result in serious privacy concerns. To overcome this problem, we formulate a multi-objective optimization problem with considering both the query probability and the practical dummy location region. A low complexity dummy location...
A compact monopole antenna with a volume of only 8×32×5 mm3 for smartphones applications is presented. The antenna consists of two meander monopoles, having an S-shape and L-shape, on one side of the substrate and a tuning stub on the other side. Simulated and measured results show that the antenna has a dual-band of 824–960 MHz and 1700–3800 MHz which can cover the frequency bands for the GSM850,...
In this paper, a wideband circularly polarized (CP) slot-antenna array is presented. A feeding network with four output ports is designed using metamaterial transmission line (MM TL) to feed four slot antenna elements, forming a sequential-rotation array (SRA) and resulting in CP operation. The antenna array is studied and designed using computer simulation and measurement. The measured results show...
Metallic components such as USB connectors used in mobile phones can easily affect the performances of antennas placed nearby. This paper illustrates the use of the metallic USB connector in a very compact loop antenna with a volume of 5×8×60 mm3 to generate an additional resonant mode at about 3.13 GHz. A standard metallic USB connector is placed inside the loop radiator of the antenna to generate...
A broadband dual-circular polarization (CP) antenna is presented in this paper. The antenna consists of square radiator fed by a feeding network with four outputs. The feeding network is designed using a 3-dB hybrid-coupler chip to obtain a sequential-phase difference of 90° at the four output ports. Simulation shows that the antenna has an impedance bandwidth (IMBW) of 37% (1.1–1.6 GHz) for |S11|<−10...
A defected ground structure (DGS) with two resonances is proposed to reduce mutual coupling of planar multiple-input-multiple-output (MIMO) antenna. A dual-band MIMO antenna is used for study. The antenna consists of two planar-inverted F-antenna (PIFA) elements printed symmetrically for dual-band operation. The defected ground structure (DGS) is placed between the two PIFA elements to reduce mutual...
This paper proposes a finite-time control law for quadrotor aircraft to achieve position tracking control in a finite time. Firstly, the position dynamical equation and the attitude dynamical equation are introduced respectively. Secondly, based on the technique of finite-time control, a finite-time position controller is designed to ensure the desired trajectory can be tracked by the real position...
An X-band metasurfaced (MS) antenna is proposed for circular polarization (CP) operation. The antenna consists of a patch antenna and a MS, which are printed on a single substrate, resulting in low profile. Results show that, with using the MS, the antenna can achieve an impedance bandwidth (IMBW) of 9.24–10.16 GHz (0.92 GHz, 9.5%) and an axial-ratio bandwidth (ARBW) of 9.54–9.94 GHz (0.4 GHz, 4.1%),...
A planar 8-port MIMO antenna consisting of only 4 slot elements is proposed in this paper. The antenna has a symmetrical structure and is designed to operate from 2.40–2.48 GHz. Each of the 4 slot elements is serving as a common radiator for 2 input ports. A T-shaped defected ground structure (DGS) is cut in the middle of the slot element to increase isolation between the two input ports to more than...
Sentinel-1 is a radar imaging satellite that was launched by ESA in 2014. By default, Sentinel-1 sensor acquires data in the mode of Terrain Observation with Progressive Scans. In this mode, data are acquired with varying Doppler centroid. Consequently, traditional InSAR processing strategies for strip-mode data cannot be directly utilized, especially when imaging areas have large scale ground deformation...
In order to overcome the influence of decorrelation phenomenon in multi-baseline InSAR techniques, the phase reconstruction technique has been developed in recent years and has become one of the hottest focuses in radar interferometry. In this paper, our recently developed simplified coherence network phase reconstruction technique is reported. With the use of Sentinel-1 data, it is firstly engaged...
The open nature of Android allows application developers to take full advantage of the system. While the flexibility is brought to developers and users, it may raise significant issues related to malicious applications. Traditional malware detection approaches based on signatures or abnormal behaviors are invalid when dealing with novel malware. To solve the problem, machine learning algorithms are...
Visual tracking is intrinsically a temporal problem. Discriminative Correlation Filters (DCF) have demonstrated excellent performance for high-speed generic visual object tracking. Built upon their seminal work, there has been a plethora of recent improvements relying on convolutional neural network (CNN) pretrained on ImageNet as a feature extractor for visual tracking. However, most of their works...
Deploying dense small cell networks overlaying to the conventional macro cell networks is widely regarded as a key step towards network architecture revolution for improved coverage and user rate. Small cells have different kinds, and a target coverage can be achieved through deploying different kinds of small cells. Previous works mainly focus their attention on the optimization of spectrum and energy...
With the advent of oceans as critical resources, ocean simulation technologies have gained momentum in various fields such as fisheries, marine biology, oil and gas. The complexity of such simulation systems not only shows through the system architecture, the data generation and analysis, but also through the cost to develop and reuse these systems. For the construction of ocean simulation environment,...
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