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With the increasing penetration of renewables in power system, secondary frequency regulation (SFR) is becoming a big challenge for conventional coal-fueled thermal generator units. To address this issue, a stricter AGC criteria to regulate the generators has been but forward. However, old-fashioned units can hardly meet the requirements and thus are subject to penalty. In this paper, an approach...
Autonomous ontology learning is a critical task to reduce the cost of ontology construction for knowledge based systems. This paper provides a cognitive model for ontology learning system, which aims to develop a novel model for knowledge structuring based on the interaction between the process of ontology construction and cognitive psychology. During cognitive process, we simulate human's cognitive...
Modeling and simulation has received significant attention over the years for its ability to understand and transform real world systems. With the increasing of complexity and scale of the simulated systems, more computational power is required. Parallel discrete event simulation(PDES) is an important technology to integrate parallel computing into modeling and simulation. Time synchronization algorithm...
Simulation results of a 0.3THz gyro-traveling wave amplifier(TWA) are presented in this paper. The gyro-TWA operates in the HE06 mode of a quasi-optical confocal waveguide using a gyrating electron beam. The amplifier has achieved a linear gain of 24.3 dB, a 3dB bandwidth of 4.0 GHz, and output power up tp 35W at a beam voltage of 18 kV, beam current of 0.15A, 10.8T magnetic field and beam pitch factor...
The mode-hopping phenomenon in extended interaction oscillator (EIO) based on the multiple-gap topology resonant system is studied to verify the remarkable advantage of the electronic tuning property for EIO. In contrast to the conventional EIO where electron beam interacts with the standing-wave mode in a narrow operating voltage range, the presented EIO can operate in a sequence of neighboring backward-wave...
This study aims at finding optimal threshold in diffusion tensor tractography (DTT) of pelvic floor muscles. Twenty healthy adults (ten males and ten females) were included in this study. Conventional MRI sequences(T1WI, FSE-T2WI) and diffusion Tensor Imaging (DTI) were acquired in GE Signa HDxt 3.0T MRI. Then the DTI were post-processed in ADW4.5 workstation. Levator ani muscle, coccygeus and obturtor...
A polarization-insensitive and compact metamaterial absorber (MMA) was proposed in S band, which could exhibit a perfect absorption for electromagnetic (EM) energy harvesting application. The unit cell design consists of an electric-LC (ELC) resonator structure loaded with resistors backed by a complementary patch. The extracted effective EM parameters and simulated surface current distributions of...
As some of the valuable satellites can maintain working after on-orbit servicing, it's meaningful to study on the autonomous rendezvous. Most of these satellites are non-cooperative, more specifically, they have no target location markers or rendezvous sensors. This paper extracts the edge of the adapter ring as natures for recognition, measurement or even mechanical docking. A practical detection...
An effective method is proposed for calculating the on-board real-time path planning of large-scale space redundant manipulators. Firstly, the 7-DOF manipulator kinematics model is described and analyzed, and the main computational process of path planning is presented. The homogeneous transformation matrices of various degrees of freedom are obtained through the telemetry joint angle, and is used...
Aiming at DNA encoding sequences design, a micro-genetic algorithm (MGA) is proposed by introducing a sharing function based on similarity and H-measure of DNA sequences. In the algorithm, six design criteria are adopted and four genetic operators are applied. Compared with the previous results, the algorithm can get better DNA sequences and improve the computational efficiency.
This work investigates the problem of extending the lifetime of dynamic WSNs with energy-harvesting (EH) sensors to enhancing the total WSN lifetime. This problem is modeled as finding the maximal number of covers each of which can cover all targets to be monitored. Since the concerned problem is also NP-complete, this work proposes a novel harmony search algorithm. By simulation, the proposed algorithm...
The operational states of power system become much more complicated and variable, since the size of power system grows larger. To secure power system operation, crucial power flow interfaces should be monitored. Therefore, a power system safe operation knowledge base should be established to help system operators to make decisions. The base works like an automatic operator (AO), which can quickly...
Classification has been among the central issues of hyperspectral application. However, due to the well-known Hughes phenomenon, most of the methods suffer from the curse of dimensionality and deeply rely on traditional dimensional reduction like Principle Component Analysis (PCA). In this paper, combining spatial and spectral information jointly, we propose a novel deep classification framework....
Experience replay is a promising approach to improve the learning efficiency of adaptive dynamic programming. A general model-free adaptive dynamic programming (ADP) approach with the experience replay technology is investigated in this paper to solve the optimal control problems in continuous state and action spaces. Both the critic network and action network are modeled with a feedforward neural...
High-voltage direct-current (HVDC) transmission-line protection is becoming increasingly desirable with the expanding worldwide popularity of HVDC technologies in recent years. This paper proposes a transmission-line backup protection scheme based on the integral of reactive power for HVDC systems. The directional characteristics of reactive power flow are theoretically analyzed for internal and external...
The low-rank property of hyperspectral imagery is well exploited with low-rank decomposition methods recently. In our approach, a novel hyperspectral anomaly detector based on low-rank representation (LRR) and learned dictionary (LD) has been proposed. This method assumes that a two-dimensional matrix transformed from a three-dimensional hyperspectral imagery can be decomposed into two parts: a low...
A test cases library is created to provide a common foundation to test methods for locating the source of a poorly damped or forced oscillation by using wide-area measurements. The library is built on a simplified WECC 179-bus system and includes both poorly damped and forced oscillation cases. Three source locating methods were fully tested using the library, and two selected cases for each method...
Half-wavelength AC transmission (HWACT) is an ultra-long distance AC transmission technology, whose electrical distance is close to half-wavelength at the system power frequency. The countries with a large territory have a big demand for HWACT. The fault characteristics of an HWACT line can be different from those of a conventional transmission line. So it is necessary and significant to analyze the...
In this paper, a driver-stage power amplifier is presented for a Doherty amplifier that worked at 2.6GHz. The simulation and measurement results meet all scheduled design indexes, which the peak output power is about 39dBm, the biggest power gain is about 15dB and the largest PAE is about 31%. It gives a method by combining the software and hardware to design and debug the power amplifier. Compared...
Traveling-wave-based protection is becoming attractive in ultra-high-voltage (UHV) transmission systems due to the requirement for high-speed protection. However, the poor transfer characteristics of coupling capacitor voltage transformers (CCVTs) for high-frequency voltage have strictly limited its application. A novel traveling-wave-based protection scheme considering the characteristics of CCVTs...
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