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In this paper, a novel dual-band suspended stripline (SSL) filter is proposed. Based on traditional designing technique, a band-pass SSL filter is designed. Considering the unique properties of metamaterials, we apply it to the filter structure designing. Metamaterials can produce negative permittivity and thus there forms a dual-band. The simulated results exhibit low insertion loss, high selectivity...
The nodes in communication networks are possibly and most likely equipped with different recovery resources, which allow them to recover from a virus with different rates. In this paper, we aim to understand know how to allocate the limited recovery resources to efficiently prevent the spreading of epidemics. We study the susceptible-infected-susceptible (SIS) epidemic model on directed scale-free...
Online social networks can detailedly and accurately record the activities of human beings and the trajectories of information dissemination over time, which provides us an opportunity to understand the information diffusion process from a renewed, more realistic, data driven modeling dimensionality. In consideration of two fundamental behaviors (viewing and sharing) involved in information diffusion,...
In this paper, a special control solution called “Virtual Voltage Source” is developed for no-load tests of induction machines. This concept is applied to a 2×27 MVA high-power machine test bench, where the test bench is requested to precisely characterize e.g. 3 MW machines at no-load currents. The developed Virtual Voltage Source thoroughly solves the stability issue of induction machines at low...
This paper presents a pumpback test bench for high-frequency high-power Variable-Frequency Drives with 11 MW power rating and up to 595 Hz load frequency. A Voltage Combiner concept is applied to allow a high-frequency output from the two IGCT bridges with minimum switching losses. The accordingly developed pumpback test bench applies a dc power coupling concept combined with a virtual grid that can...
With the rapid development of remote sensing technology, huge quantities of high resolution remote sensing images are available now. Understanding these images in semantic level is of great significance. Hence, a deep multimodal neural network model for semantic understanding of the high resolution remote sensing images is proposed in this paper, which uses both visual and textual information of the...
Power capability is one of the most important criteria for converters in high-power applications. The normal approach for converters increasing the power capability is to use devices with larger Safety Operating Area (SOA). In this paper, a novel control method is proposed to realize power capability improvement at low carrier ratios without hardware changes. It uses the carrier modulation at integer...
Recent research on skyline queries has attracted much interest in the database and data mining community. The concept of dominant relationship analysis has commonly used in the context of skyline computation, due to its importance in many applications. Current methods have only considered so-called min/max hard attributes like price and quality which a user wants to minimize or maximize. However,...
Skyline query asks for a set of interesting points that are non-dominated by any other points from a potentially large set of data points and has become research hotspot in database field. Users usually respect fast and incremental output of the skyline objects in reality. Now many algorithms about skyline query have been developed, but they focus on static dataset, not on dynamic dataset. For instance,...
Outlier mining, also called outlier detection, is a challenging research issue in data mining with important applications as intrusion detection, fraud detection and medical analysis. From the perspective of data, previous work on outlier mining have involved in various types of data such as spatial data, time series data, trajectory data, and sensor data. However, few of them have considered a constrained...
The STM32F103RBT6 chip based on ARM Cortex-M3 is used as processor, and the FSBS3CH60 chip—one of Mini SPM series is used to drive motor in this paper. A kind of sliding mode observer (SMO) is designed to estimate motor rotor position and speed for sensorless permanent magnet synchronous motor (PMSM) control problems. The SMO adopts adjustable parameters of sigmoid function as the switch function,...
The basic working principle of the stepper motor and its controlling method are introduced in this paper. The performance of the microprocessor STM32F103RBT6 and the driving principle of stepper motor driver chip L6208 are analyzed. A new type of stepper motor controller is designed. The input plus of the driver IC is provided by direct digital frequency synthesizer (DDS) chip. It describes how to...
In this paper, the impact of dc-link voltage ripples on the machine-side spectrum is investigated. The analysis is targeted for a high-power converter using NPC H-bridge topology. Due to the high amplitude of 2nd harmonic and additional f0/2 sub-harmonic that is introduced by a special modulation scheme, their impacts on the machine are at question. In this work, these questions are addressed via...
The position sensorless vector control scheme for the brushless excited synchronous motor based on the IGCT converter is presented in this paper. Since the instantaneous excitation current cannot be directly measured in this application, an adaptive rotor position and speed observer, which does not rely on the explicit estimation of the excitation current, is developed for the brushless excited synchronous...
For high-power converters with low pulse ratios (e.g. 80 Hz load frequency with 600Hz carrier frequency for a 27 MVA Variable Frequency Drive), the current control loop design has been a challenge due to the large signal delay and potentially higher-order plant (LCL filter between the converter and machines). The stability issue and cross-coupling effect is a problem in such application. In this paper,...
In this paper, control strategies of a 22 MW / 27 MVA machine test bench using pumpback topology are introduced. The current loop design at extremely low pulse ratios (e.g. 600 Hz carrier frequency / 80 Hz load frequency) is developed. The system stability and dynamic response are analyzed. The challenges for high-power machine control with a sine filter and a transformer connected between the voltage-source-inverter...
Researches on Arctic aerosol, ice cover and cloud cover have received great attention and it related to the regional even global climate changing. We here study the distributions and the coupling relationships of AOD, cloud cover (CLD) and ice cover (ICE) in the Greenland Sea (20°W–10°E, 70°N–80°N) during 2003–2012. Enhanced statistics methods, such as lag regression method and co-integration analysis...
This paper demonstrates the impact of modulation schemes on the power capability of a high-power converter with low pulse ratios. This IGCT converter uses a five-level Neutral-Point-Clamped H-bridge topology. It is concluded that phase-shifted carrier modulators are not attractive for such converters at low pulse ratios due to the poor THD (Total Harmonic Distortion) performance and poor power capability...
In this paper, a high-performance 22 MW/27 MVA machine test bench using pumpback topology is introduced. It proposes a cost-effective concept that works reliably even with a weak grid. A paralleling concept of two three-level IGCT converters is presented. It generates a five-level pulse pattern with low harmonic distortion at 600 Hz carrier frequency and 80 Hz load frequency. The selected magnetic...
We study the feasibility condition for a new IA strategy which is referred to as “Partial Interference Cancelation-based Interference Alignment” (PIC-IA). Unlike the conventional interference alignment (IA) strategy, PIC-IA aims to remove the most significant interference signals, and what we concern about the scheme is how many interference signals can be aligned and canceled for a system. And in...
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