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SiC JFET bi-directional switches (BDS) are widely used in construction of matrix converters, multi-level converters, solid state switches, etc. In this research work, the phenomenon of unwanted turn-on (UTO) of SiC JFET-based BDS and its related constant envelop oscillation is investigated. This phenomenon is critical to power conversion systems' stability and reliability. Firstly, the roots of UTO...
There are many function modules in the numerical control (NC) system, the system needs to communicate with each other through the data interaction among modules, to coordinate the work between modules and complete the control task. In this paper, the main function module structure of NC system is constructed based on RCS method. The communication between the NC system modules is realized by using...
The well-known maximum torque per ampere (MTPA) strategy is usually integrated the field oriented control (FOC) to improve the efficiency of interior permanent-magnet (IPM) synchronous motor drives. As an alternative to the FOC, direct torque control (DTC) has attracted extensive attention from both academia and industry in the last few decades, due to its distinctive advantages, e.g., fast dynamic...
The photovoltaic (PV) source simulators are widely used to test solar inverters, evaluate their control algorithms and study their grid integration issues in the laboratory settings. Many commercial programmable dc power supplies can be re-programed to be PV simulators. Due to the bulky output dc capacitors, the dynamic response and the bandwidth of these PV simulators are significantly limited, which,...
Communication bandwidth inconsistency between traditional secondary control and tertiary control may decrease the economic efficiency of a microgrid. To solve the problem, this study proposes a fully distributed cooperative strategy in secondary level to minimize the operation cost in an AC microgrid and achieve the synchronization of the voltage and frequency. The proposed strategy is based on the...
Compared to the traditional AC-DC-AC power converter, the matrix converter (MC), as a kind of universal power transformation device, can easily achieve n phase to m phase transformation. The matrix converter can generate controllable sinusoidal output voltage and input current, provide unit input power factor, have no intermediate storage link and energy can be bi-directional transferred with fast...
In this paper, a new all optical flip-flop structure based on semiconductor optical amplifier (SOA) and Mach-Zehnder interferometer (MZI) is presented and demonstrated. Through carrying out a detailed analysis of SOA's NPR effect and the coupled SOA-MZI structure, we build up a theoretical SOA model with polarization dependent rate-equations and MZI model employing SOA cross-phase modulation in the...
In the actual process, the structure of the Heavy-duty machine are often subjected to influence of various force load and thermal load, and then structure is deformed, resulting in processing errors. Currently, one of the main factors restricting the high-duty heavy machine to further improve accuracy is machine structural deformation. International Society for Production Engineering reports that...
The signal acquisition system was designed, and the voltage drop of the anode rod of three anodes in the same cell was measured. After the data is processed, the current signal of anode in aluminum electrolysis process is analyzed by wavelet transform. The main frequency range of the anode current in different position is found by the spectrum analysis of the third layer detail signals and the approximation...
Person re-identification has become a hot research topic due to its importance in surveillance and forensics applications. The purpose of person re-identification is to find the same person from disjoint camera views at different time. Most of the existing methods try to identify the person by measuring the similarity of two still images from different camera views, which only uses intraimage features...
This paper develops the joint capacity and appointment scheduling model considering both no-show and walk-in patients with the objective of minimizing the total revenue of all patients minus the cost incurred by patients' waiting, physician's idleness and overtime. Under the assumption of deterministic service time and monotonic non-decreasing convex function of waiting and overtime cost, the objective...
During the deep space exploration missions a lot of attitude maneuvers need to be completed for the change of different attitude. Meanwhile, in the course of the explorer attitude maneuver there are many attitude pointing constraints due to the diversity of space tasks. Firstly, attitude kinematic and dynamic equations based on quaternion are established in this paper, which laid the foundation for...
Since several years, satellite communications are playing a remarkable role in telecommunications infrastructures, thus the increasing interest in transporting internet traffic over satellite links. Many technologies such as the deployment of multicast and real-time audio/video streaming application are likely to increase the percentage in the context of TCP traffic in internet. The Transport Control...
AAC(Advanced Audio Coding) is the most popular audio compression standard and used widely in recent years. The steganography schemes of AAC emerged gradually. This paper presents a novel steganalysis method to attack the steganography of Huffman codebook, which hide information by modifying the codebook of each scale factor band(SFB), and have good imperceptivity and security. Based on the correlation...
Simultaneous Algebraic reconstruction technique (SART) has been widely applied to CT image reconstruction, but it is influenced by the noise interference, and as a result, the image quality is affected. In this article, we propose a modified SART algorithm to improve the quality of the image reconstruction, which constructs a new diffusion coefficient by the PM model, and makes the SART algorithm...
In this paper, we propose a theoretical model for the service composition in MCE. A user sends service requests to the MCE. Each service request can be satisfied from multiple clouds (i.e., service composition). Given this model, we then design a multi-layer algorithm to minimize the service composition overhead. The overhead is measured through two fundamental metrics: (1) the average number of clouds...
Hough transform (HT) is a typical method to detect or segment geometry objects from images. In this paper, we study the principle of Hough Transform and its mathematical expressions, and try to use a new approach based on Hough transform for quick line and circle detection in image processing. Our method accurately detected some simple graphics, such as straight line of different direction, circles...
A mode-locked all-normal-dispersion rod-fiber laser with large core diameter was demonstrated. Output power of 16 W with 270 fs pulse duration is generated. To best knowledge this is the first laser operation with 85 μm core fiber.
Exploits diagnosis requires great manual effort and desires to be automated as much as possible. In this paper, we investigate how the syntactic format of program inputs, as well as reverse engineering of data structures, could be used to identify overwritten data structures, and propose a binary-level exploit diagnosis approach, deExploit, that is generic to attack types and effective in identifying...
Coverage-based fault localization techniques leverage coverage information to identify the suspicious program entities for inspection. However, coincidental correctness (CC) widely occurs during software debugging, and brings negative impact to the effectiveness of CBFL techniques. In this paper, we propose a regression approach to identity CC execution with weighted clustering analysis. Based on...
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