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Digital-physical hybrid real-time simulation is considered to be an advanced method for future power system simulation. However, the physical interface will inevitably exist DC component, which causes negative effects on practical applications, such as degradation of simulation performance, damage to physical equipment, etc. A novel DC component elimination control strategy for the digital-physical...
Attendance is an important part of classroom evaluation. This paper develops a university classroom automatic attendance system by integrating two deep learning algorithms MTCNN face detection and Center-Face face recognition. A large number of experimental results show that: (1) The system can record such three violations of classroom discipline for automatic attendance, that is absence, lateness...
In this paper, we propose a fast design procedure for the low scattering metasurface in the microwave region. Since there are numerous units with various geometric dimensions inside the metasurface aiming to generate a diffusion-like scattering pattern, it presents a large computation burden for the evaluation and optimization of the scattering behaviors of the whole metasurface. To overcome this...
The recently emerging SiC devices provide a promising solution to improve power converter efficiency and power density. However the expensive cost limited the widely use of SiC device. The parallel connection of SiC MOSFET and Si IGBT is introduced in this paper to utilize the advantage of this two different kinds of devices and proposed corresponding switching strategies. The switching loss and current...
This paper presents a guidance law design for synchronized path following of multiple underactuated unmanned surface vehicles (USVs) without using a global reference velocity. Firstly, a distributed observer is proposed to eliminate the need of reference velocity known to all the vehicles. Secondly, a line-of-sight based guidance law is derived to force each vehicle to follow a parameterized path...
A novel image fusion method based on region gradient and SWT is proposed to improve the visual effect of the fused image. The source images are first decomposed into low frequency and high frequency parts. Low frequency parts are fused using the fusion rule of larger region gradient, and the absolute value is adopted as the fusion rule for high frequency parts. The final fused image is obtained by...
Digital-analog hybrid simulation method combines the advantages of both real-time digital simulation and physical simulation, and will be an effective means for the simulation and analysis of future power system. However, the ideal transformer model (ITM), as the most widely used interface algorithm, is easy to encounter instability issues. A novel impedance compensation algorithm based on ITM is...
We report the first operation of a widely-tunable 8-period undulator at terahertz (THz) frequencies in the Tsinghua University beamline. We observed the coherent undulator radiation from sub-picosecond electron bunches of 30MeV. The measured radiation curve shows clearly that the radiation energy is proportional to the charge square, and the THz frequency can be changed from 0.4 THz to 10 THz with...
Qiandongnan Prefecture (QDN) is located in southeast of Guizhou province, China. There are 2900 rivers in this region and it plays a vital role in the soil and water conservation of the Yangtze River upstream watershed. It is also one of the regions of richest biodiversity in China. This paper studied the effects of the Grain to Green in Qiandongnan Prefecture based on remote sensing monitoring. The...
Generating video description is a very challenging task due to the complex spatiotemporal information. Recently, many methods have been proposed by utilizing LSTM to generate sentence for video. Inspired by recent work in machine translation and object detection, we propose a new approach for video captioning which aims to incorporate Knowledge Base information with frame features of the video. We...
This paper presents a detailed experimental approach for understanding and optimizing the hover performance of Martian UAV rotor, including a systematic discussion about several coefficients for hover characteristics and a detailed design approach for rotor blades of Martian UAV at Reynolds numbers lower than 50000. The discussed hover performance coefficients include figure of merit, thrust coefficient,...
A novel printed planar double inverted-F antenna (DIFA) with enhanced gain is proposed, whose bands are 1.78–1.88 GHz, 2.25–2.48 GHz as well as 5.33–5.8 GHz, respectively. In this design, the antenna occupies small size with length of 80 mm, width of 45 mm and height of 1.6 mm and is etched on FR4 substrate with half plane ground. The results of simulation and experiment indicate that this type antenna...
Computer-aided diagnosis (CAD) of liver cancers on contrast-enhanced ultrasound (CEUS) has attracted considerable attention in recent years. The enhancement patterns on CEUS for liver lesions consist of the arterial, portal venous and late phases. Several typical images selected from these three phases can provide reliable information basis for diagnosis of liver lesions. Therefore, we propose to...
The contrast-enhanced ultrasound (CEUS) has been a widely accepted imaging modality for diagnosis of liver cancers. In clinical practice, several typical images selected from enhancement patterns of the arterial, portal venous and late phases can provide reliable information basis for diagnosis. In this work, we propose to develop a CEUS-based computer-aided diagnosis (CAD) for liver cancers with...
This paper is concerned with the disturbance estimation and state recovery of autonomous surface vehicles in the presence of uncertainty and unmeasured surge, sway, and yaw velocities by using the position-yaw measurements only. The uncertainty stems from parametric model uncertainty, unmodelled hydrodynamics, and external disturbance, which are induced by wind, waves and ocean currents. By using...
In this paper, a distributed guidance law at the kinematic level is developed for coordinated maneuvering of networked fully-actuated autonomous surface vehicles with a virtual leader that moves along a parameterized path. We design the distributed guidance law based on the constant bearing guidance scheme and a path maneuvering design. We prove that the error signals in the closed-loop guidance system...
This paper considers coordinated path following of multiple underactuated unmanned surface vehicles (USVs) subject to dynamical uncertainties and limited control torques. The objective is to achieve a symmetric formation pattern over a closed curve. Adaptive coordinated path following controllers are developed by combing a parameter cyclic pursuit approach, a line-of-sight guidance principle, and...
This paper presents a guidance law design for synchronized path-following of multiple under-actuated unmanned surface vehicles (USVs) in the presence of unknown sideslip. The sideslip can be caused by wind, waves, and ocean currents, or arise when following a curved path. An adaptive guidance law is proposed based on a line-of-sight (LOS) guidance principle and a low-frequency learning scheme. By...
An innovated evolving network representation model to characterize weighted, complex, scale-free networks is proposed. A new node or a community is added to network in the process of evolution while emergences of new links occur according to the ‘Triad Formation’ possessing symmetry and the random selection mechanism. A weighted scale-free network with high-value clustering coefficient can be obtained...
In this paper, we present a novel framework to incorporate high-level guidance and low-level features to automatically identify salient objects based on two ideas. The first one considers the specific location prior to encode visual saliency, while the second one estimates image saliency using contrast with respect to background regions. The proposed framework consists of the following three steps:...
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