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Link prediction is a fundamental problem in social systems, including the prediction of user interaction and the links between users and items, which is also referred to as recommendation. Previous works mainly focus on the prediction task independently, which predict either the links between users or the links between users and items. However, these two prediction tasks are always coupled with each...
This paper presents a biased flux hybrid-excited flux switching (BFHEFS) machine to improve the flux adjustability. The proposed configuration adopts E-core to enhance the permanent magnet (PM) material utilization ratio, which use half PMs of the conventional flux switching PM (FSPM) machine. The flux-adjusted principle of the E-core BFHEFS machine is introduced to explain the better flux adjustability...
The Visible Light Communication (VLC) is a good candidate technology for the application of Intelligent Transportation System (ITS). This paper focuses on typical application scenario between the traffic lights and lorry fleet. Based on the theoretical analysis and numerical calculation, we get the relationship between the speed of the lorry fleet and the conversion time of the traffic lights. The...
A novel model of space electromagnetic docking is established to solve the problem of traditional plume contamination and short service life in this paper. A new modelling technique regarding space electromagnetic docking for CubeSat is proposed. The mathematical model with four core-containing energized solenoids is derived and simplified to the magnetic dipole far-field model of single-turn coil...
The control problem of underactuated spacecraft chaotic attitude motion is investigated based on exponential reaching law in this paper. First, the underactuated spacecraft chaotic attitude system is written in nonlinear equation form with two controls. Once the trajectory planning of angular acceleration is preset, the dynamics equation of angular velocity error can be obtained. Then, the sliding...
In our study, multi-temporal HJ-CCD data are used to identify and monitor the powdery mildew (Blumeria graminis f. sp. triti) on winter wheat on a regional scale. A total of five sensitive vegetation indices (NDVI, RDVI, SAVI, TVI, and MSAVI) are specifically derived to construct the minoring models, which can reflect the leaf area index (LAI), chlorophyll (Chl) and changes of crop canopy structure...
In this paper, we present a new unsupervised classification method based on a novel polarization feature, which reflects the proportion of co-polarization component and cross-polarization component of scatters in PolSAR image. We combine this novel polarization feature with backscattering power and scattering power entropy to perform the initial classification. Then apply a merge criterion to merge...
There is an ever-increasing interest in studying temporal networks nowadays, as temporal networks can illustrate the real-world system more accurately. To date, how to characterize nodes' importance is still unclear in temporal networks. In this work, we first use a time window graph model to cut the temporal network into slices, and then we give an indicator for network centrality according to the...
Wireless Sensor Networks(WSNs) are expected to be used in a variety of different applications. One of the most important problems in WSNs is sweep coverage. Sweep coverage utilizes mobile sensor nodes to monitor Points Of Interests (POIs). Thanks to the mobility, sweep coverage can cover more POIs using fewer sensor nodes. In practice, mobile sensor nodes can often collect the data from POIs at a...
In multi-phase machines, the third harmonic current can interact with the third harmonic back-EMF to improve the output torque. This paper investigates the unequal tooth width and permanent magnet (PM) segmentation techniques to improve the third harmonic back-EMF of the five phase 10-slot/8-pole surface-mounted permanent magnet (SPM) machine. It is found that the fundamental and third harmonic winding...
Sweep coverage is an important problem in wireless sensor networks. With sweep coverage, more Points Of Interests (POIs) can be monitored with fewer mobile sensor nodes thanks to the mobility of the nodes. Most existing studies on sweep coverage focus on the trajectory of the mobile sensor nodes to guarantee the sweep coverage of the POIs. Considering the fact that, in many applications, the collected...
This paper includes mixed matrix estimation of underdetermined blind source separation (UBSS) under the anechoic mixing model and introduces single source points to the anechoic mixing model. First, we adopt a clustering algorithm to get the amplitude in the mixing matrix. Then, utilizing the amplitudes, We use a single source point detection method to determine the presence of only one source signal...
This paper proposes a new breed of solid-state transformer (SST) distribution tail system mainly based on hybrid cascaded multilevel converter and resonant DC-DC converters between medium-voltage distribution and low-voltage customer side. The proposed SST topology mainly combines per-phase cascaded H-bridge converters based on the DC transformers (DCTs) with the square-wave two-level VSC based on...
This paper proposes a novel individual phase current control scheme for star-connected cascaded power electronics transformer (PET) under unbalanced grid voltage conditions, and PET mainly combines the cascaded H-bridge converter with resonant DC-DC converters (CLLC) between medium-voltage distribution and low-voltage customer DC side. Compared with traditional DQ decoupling current control, each...
The converter of multi-phase switched reluctance motor (SRM) requires both less switch devices and independence between phases for low-cost and high- efficiency. To achieve the above requirements, a novel N+2 power converter is employed in this paper. New converter topology combines the advantages of both asymmetric half bridge converter and split phase converter. In the base of the split phase converter,...
The current controller with fast transient response and satisfactory steady state characteristics is required in PMSM Servo System. In this paper, the application of active disturbance rejection control (ADRC) for current loop is proposed and the design proceeding of a first- order ADRC controller in the current loop is elaborated. Then, by taking use of the ADRC controller and the analysis of the...
In order to replace the traditional high-resolution position sensors in the permanent-magnet synchronous machines (PMSM), the digital Hall-effect sensors are commonly employed to estimate the rotor position and speed. However, the traditional estimated method based on the average speed results in position error due to the six discrete Hall-effect signals in one resolution at low speed, which will...
In the traditional switched reluctance machine drive(SRD), the energy exchange between power supply and electric machine could induce current ripple. Bus Peak Current Control Strategy is a new approach to reduce the DC-Link current ripple by minimizing peak current and filtering commutation-induced harmonic wave. A single current sensor is employed to realize the strategy which cut down cost and improve...
When the single earth-return line of HVDC (High voltage direct current) system is functioning, the AC system in the same area will probably be influenced. Because two converting station at different DC potential constitute a loop via transmission line, causing certain direct current moving into the transformer neutral point and winding. The transformer DC magnetic biasing phenomenon will appear, leading...
This paper first briefly introduces the basic structure of converter transformer, analyses the mechanism of vibration through simulation of the converter transformer oil-tank, designs the test scheme. This paper introduces the application of wavelet analysis method in converter transformer fault identification, then apply these methods to 24 converter transformers to obtain the characteristics parameters,...
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