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Time delay estimation is the basis of the localization algorithm for partial discharge (PD) based on time difference in GIS, and it is the key to the accuracy of localization. In this paper, the theory of fractional Hilbert transform for time delay estimation is described. Based on fractional Hilbert transform, a method for estimating the time delay of GIS ultra high frequency partial discharge is...
Shortage of qualified cybersecurity workforce is a national problem. Without an effective solution, people's daily lives, business operations, and even national security are in jeopardy. Higher education institutions have invested in various approaches to train college students to acquire cybersecurity related knowledge, skills, and abilities. The existing approaches still need improvement and refinement...
We consider the muti-user muti-content downloading service with the help of idle users working as contents servers in device-to-device (D2D) underlay network. Taking the contents distribution into account, we propose a hybrid transmitting strategy and investigate the performance enhancement it brings about. Then by formulating the helper finding and resource allocation as a minimum downloading time...
Device-to-Device (D2D) communication underlaying cellular networks is expected to bring significant benefits for resource utilization and cellular coverage. However, the resource allocation and power control needs elaborate coordination, otherwise it may cause severe interference between D2D user equipment (DUE) and cellular user equipment (CUE). In this paper, we study the joint radio resource allocation...
The realization and characterization of an all-solid photonic bandgap fiber (AS-PBF) with a compact size of about 10 mm by means of fully infiltrating an ultraviolet (UV) curable polymer with a high refractive index of 1.515 into air holes of a photonic crystal fiber (PCF) is demonstrated. It appears to a high wavelength sensitivity of up to −4.034 nm/°C. Compared with conventional fluid filled PBFs,...
Electronic devices and solder joints inside the devices are always exposed to thermal loads, which would change the microstructure of solder joints. It is well known that the growth of the intermetallic compound between bulk solder and substrate and the change of the structure in bulk solder itself might lead to fatigue crack of solder joints. The objective of this study is to demonstrate the change...
Active Contour method has been shown very effective in detecting the contour of region(s)-of-interest(ROI) and is widely used in image processing and computer vision. In this work, we aim to improve the performance of Zhang's method in detecting boundary of ROIs. Specifically, we will generalize the CV energy functional and give a new special case. The new energy functional penalize the approximation...
As the spacecraft relative motion control actuated by inter-satellite electromagnetic forces become a key concern in the space domain, the need to analyze the specific dynamic characteristics is apparent and important for better control performance. Based on the assumption of large separation distance between spacecraft and a circular reference orbit of the formation mass center, the relative translational...
This paper quantifies the benefit of the borehole array summer active recharge in the context of a small community heating system. The system uses a low carbon energy chain - specifically photovoltaic panels to supply electricity, a borehole array for heat storage, an air source heat pump for summer active recharge and a ground source heat pump for heating supply in the winter. By comparing two different...
A modified state-based potential game approach is proposed for the distributed economic dispatch problem in smart grid. Its basic idea is to formulate the objective function of each agent in the designed game as a local estimated Lagrange-like function, thus the stationary state Nash equilibrium incorporates exactly the global optimum of the original centralized economic dispatch problem. This approach...
Conventional multiphase image segmentation methods perform well in segmenting piecewise constant or local piecewise constant images. However, real images usually contain intensity variation induced by illumination inhomogeneity, small scale details, texture and noise. This brings great challenges to image segmentation and heavily degenerates the performance of the conventional methods. In this work,...
Salient object detection in hyperspectral imagery has drawn people's attention in recent years. Some detection methods which focus on extending Itti's visual saliency model into spectral domain have been proposed. However, these methods are sensitive to high-contrast edges and cannot preserve boundary of salient object well. To address these shortcomings, we propose a region-based spectral gradient...
The transformation of the existing power grid into smart grid is a key engineering priority. Information systems are a crucial enabling technology for smart grid, and the interaction between information technology and physical power systems is becoming deeper and more central. Conventional distribution network planning, which tends to ignore this close interaction, is unable to meet the development...
Sparse coding provides an excellent image prior for hyperspectral images (HSIs) denoising. However, on one hand, it is challenging to capture the structure within each sparse code for improving the reconstruction accuracy, on the other hand, the inconsistent recovery of the sparse codes corrupts the spectrum similarity in each homogeneous cluster of the HSI. To address these problems, we first propose...
This paper proposes a new model to remove the multiplicative noise. We incorporate the cartoon-texture decomposition into a multiplicative denoising model, and design a new convex optimization model. The superiority of the proposed model lies in adding the H−1 norm of texture component, which can help to recover more image information. We solve the model numerically by Douglas-Rachford splitting algorithm...
Subspace clustering aims to reveal the latent subspace structure underlying high dimensional data by segmenting the data into corresponding subspaces. It has found wide applications in machine learning and computer vision. Most recent works on subspace segmentation focus on subspace representation based methods, which constructs the affinity matrix from the subspace representation of data points....
This paper studies the stability and steady state of DC microgrids with distributed cooperative droop control that works in the second level and is based on the current errors between neighboring nodes. It is shown that the stability problem is equivalent to the semistability problem of a class of second-order matrix system, followed by some further sufficient conditions. A simulation example on the...
The gravity wave is a physical phenomenon beyond time and distance. It could lead to the distortion of time and space accompanied with the release of energy. The Laser Interferometer Gravitational-Wave Observatory (a.k.a LIGO) is a large-scale physics experiment aiming to directly detect gravitational waves. The data on which we study came from LIGO Science Run 6 (S6) with more than 1000 channels...
A new backstepping control scheme for piezoactuator-driven stage using prescribed performance is proposed. The piezoactuator-driven stage's hysteresis behavior is described by Bouc-Wen model. A prescribed performance bound is used to tackle the tracking error's convergence rate and maximum overshoot. H-infinity robust control is used to improve the robust controllability of the piezoactuator-driven...
In this paper, the chaotic motion of micro-cantilever tip in AFM is considered. A disturbance observer based control approach is proposed. The proposed control approach is composed of state observer, disturbance observer and baseline controller. It is also relatively easy to be realized based on the measurable control input and system output signal. The developed control approach is able to suppress...
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