A Multi-category Task for Bitrate Interval Prediction with the Target Perceptual Quality

( Zhenwei Yang ),( Liquan Shen ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.12

Video service providers tend to face user network problems in the process of transmitting video streams. They strive to provide user with superior video quality in a limited bitrate environment. It is necessary to accurately determine the target bitrate range of the video under different quality requirements. Recently, several schemes have been proposed to meet this requirement. However, they do not take the impact of visual influence into account. In this paper, we propose a new multi-category model to accurately predict the target bitrate range with target visual quality by machine learning. Firstly, a dataset is constructed to generate multi-category models by machine learning. The quality score ladders and the corresponding bitrate-interval categories are defined in the dataset. Secondly, several types of spatial-temporal features related to VMAF evaluation metrics and visual factors are extracted and processed statistically for classification. Finally, bitrate prediction models trained on the dataset by RandomForest classifier can be used to accurately predict the target bitrate of the input videos with target video quality. The classification prediction accuracy of the model reaches 0.705 and the encoded video which is compressed by the bitrate predicted by the model can achieve the target perceptual quality.

Laser Vision-Based Automatic Trajectory Planning Technology for Spatial Intersecting Joint Weld

Zhenwei Jia,Tianqi Wang,Liangyu Li,Junjie He 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.1

This paper studies the laser vision-based automatic trajectory planning technology for spatial intersecting joint weld. Firstly, the mathematical model of T-type off-axis non-groove intersecting joint is established, and the welding seam characteristics of the intersecting joint are analyzed. Secondly, a triangular pseudo-rotation feature pixel detection algorithm based on monocular structured light vision is proposed to realize the rapid extraction and location of spatial intersecting joint weld. Then, a laser vision-based calibration method for the workpiece coordinate system of the T-type intersecting joint is proposed, the relationship between intersecting joint workpiece coordinate system and robot base coordinate system is established, and the trajectory equation is obtained. At last, a searching discrete of chord error interpolation control algorithm is proposed to automatically discrete and plan welding torch gesture data. Experiments show that the technology can achieve higher precision location and better intersecting joint weld trajectory planning, and realize high-quality automatic weld of intersecting joint.

Resource Allocation Algorithm Based on Simultaneous Wireless Information and Power Transfer for OFDM Relay Networks

( Zhenwei Xie ),( Qi Zhu ),( Su Zhao ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.12

A resource allocation algorithm based on simultaneous wireless information and power transfer (SWIPT) to maximize the system throughput is proposed in orthogonal frequency division multiplexing (OFDM) relay networks. The algorithm formulates the problem under the peak power constraints of the source and each subcarrier (SC), and the energy causality constraint of the relay. With the given SC allocation of the source, we give and prove the optimal propositions of the formulated problem. Then, the formulated problem could be decomposed into two separate throughput maximization sub-problems by setting the total power to transfer energy. Finally, several SC allocation schemes are proposed, which are energy priority scheme, information priority scheme, balanced allocation scheme and exhaustive scheme. The simulation results reveal that the energy priority scheme can significantly reduce computational complexity and achieve approximate performance with the exhaustive scheme.

Nanocomposite Ni-CGO Synthesized by the Citric Method as a Substrate for Thin-film IT-SOFC

Zhenwei Wang,Yu Liu,Shin-ichi Hashimoto,Masashi Mori 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.12

Ni-ceria cermets have been extensively investigated as candidates for the anode in intermediate-temperature solid oxide fuel cells. We have used the citric method to synthesize nanocomposite powders consisting of NiO (Ni metal content: 40~60% by volume) highly dispersed in Ce0.9Gd0.1O1.95 (CGO). The microstructure characteristics and sintering behaviors of the nanocomposites were investigated. No impurity phases were observed and the shrinkage of these substrates matched well with that of a CGO electrolyte with a specific surface area of 11 m2/g. Densification of the CGO electrolyte layer to <5 μm thickness was achieved by co-firing the laminated electrolyte with the porous NiO-CGO substrate at 1400oC for 6 h. Ni-ceria cermets have been extensively investigated as candidates for the anode in intermediate-temperature solid oxide fuel cells. We have used the citric method to synthesize nanocomposite powders consisting of NiO (Ni metal content: 40~60% by volume) highly dispersed in Ce0.9Gd0.1O1.95 (CGO). The microstructure characteristics and sintering behaviors of the nanocomposites were investigated. No impurity phases were observed and the shrinkage of these substrates matched well with that of a CGO electrolyte with a specific surface area of 11 m2/g. Densification of the CGO electrolyte layer to <5 μm thickness was achieved by co-firing the laminated electrolyte with the porous NiO-CGO substrate at 1400oC for 6 h.

Nanocomposite Ni-CGO Synthesized by the Citric Method as a Substrate for Thin-film IT-SOFC

Wang, Zhenwei,Liu, Yu,Hashimoto, Shin-ichi,Mori, Masashi The Korean Ceramic Society 2008 한국세라믹학회지 Vol.45 No.12

Ni-ceria cermets have been extensively investigated as candidates for the anode in intermediate-temperature solid oxide fuel cells. We have used the citric method to synthesize nanocomposite powders consisting of NiO (Ni metal content: $40{\sim}60%$ by volume) highly dispersed in $Ce_{0.9}Gd_{0.1}O_{1.95}$ (CGO). The microstructure characteristics and sintering behaviors of the nanocomposites were investigated. No impurity phases were observed and the shrinkage of these substrates matched well with that of a CGO electrolyte with a specific surface area of $11\;m^2/g$. Densification of the CGO electrolyte layer to $<5\;{\mu}m$ thickness was achieved by co-firing the laminated electrolyte with the porous NiO-CGO substrate at $1400^{\circ}C$ for 6 h.

Research on Dual-Operation Mode of 3-Level LLC Resonant Converter

A. Zhenwei Li,B. Lei Zhao,C. Yuan Liu,D. Haoyu Li 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In order to meet the demands of high efficiency and a wide adaptable range of input voltage, a Dual- Operation Mode half-bridge LLC converter which can operate in two different modes according to the level of input voltage is obtained by adjusting the driving control strategy of 3-level LLC resonant converter, and the adaptable range of input voltage is doubled with the same parameters of resonant tank. The limiting factors on adaptable range of input voltage are defined by analyzing the voltage gain characteristic and power loss of LLC converter. After analyzing the Dual-Operation Mode of 3- level LLC converter and its influence on the adaptable range of input voltage, the driving control strategy is defined. The characteristic about wide input adaptability and high efficiency of the Dual-Operation Mode half-bridge LLC converter are verified through simulation and experiments.

Super Twisting Observer based Repetitive Control for Aperiodic Disturbance Rejection in a Brushless DC Servo Motor

Raymond Chuei,Zhenwei Cao,Zhihong Man 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.5

This paper presents a super twisting observer based repetitive control (STORC), which can not onlytrack the periodic signals precisely, but also reject aperiodic disturbances. Firstly, a stable repetitive control (RC) isdesigned based on the small gain theorem to track the periodic references, and compensate the periodic disturbances. Secondly, a robust exact differentiator is employed to estimate the velocity required by the disturbance observer. Finally, the super twisting observer (STO) is constructed to reject aperiodic disturbances, and input unmatchedperiodic disturbances with reduced chattering. The stability analysis is conducted and the design conditions arederived for a stable system. The proposed algorithm is simulated in MATLAB Simulink, and verified on a brushlessDC servo motor in real time to demonstrate the effectiveness. The comparison studies highlight the advantages ofthe proposed algorithm.

Design of a Robust Discrete-time Phase Lead Repetitive Control in Frequency Domain for a Linear Actuator with Multiple Phase Uncertainties

Maria Mitrevska,Zhenwei Cao,Jinchuan Zheng,Edi Kurniawan,Zhihong Man 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.6

This paper presents a simple and effective design of a discrete-time repetitive control (RC) in frequency domain. Unlike existing phase lead RC designs, the proposed approach provides flexible phase lag compensation at multiple frequencies, which ensures improved tracking performance and robustness against system uncertainties over a wide bandwidth. The proposed design is applied to a linear actuator (LA) with friction and payload variations. The robust stability analysis presented in this study demonstrates the effectiveness of the proposed method in the presence of multiple system uncertainties. Both simulation and experimental results validate the improvement. While, the comparison study shows the superiority of the proposed approach.

A two-stage source extraction algorithm for temporally correlated signals based on ICA-R

Hongjuan Zhang,Zhenwei Shi,Chonghui Guo,Enmin Feng 한국전산응용수학회 2008 Journal of applied mathematics & informatics Vol.26 No.5

Blind source extraction (BSE) is a special class of blind source separation (BSS) methods, which only extracts one or a subset of the sources at a time. Based on the time delay of the desired signal, a simple but important extraction algorithm (simplified ” BC algorithm”)was presented by Barros and Cichocki. However, the performance of this method is not satisfying in some cases for which it only carries out the constrained minimization of the mean squared error. To overcome these drawbacks, ICA with reference (ICA-R) based approach, which considers the higherorder statistics of sources, is added as the second stage for further source extraction. Specifically, BC algorithm is exploited to roughly extract the desired signal. Then the extracted signal in the first stage, as the reference signal of ICA-R method, is further used to extract the desired sources as cleanly as possible. Simulations on synthetic data and real-world data show its validity and usefulness.

ONLINE OPTIMAL CONTROL STRATEGY METHODOLOGY FOR POWER-SPLIT HYBRID ELECTRIC BUS BASED ON HISTORICAL DATA

Xiaohua Zeng,Zhenwei Wang,Yue Wang,Dafeng Song 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.5

An online optimal control strategy methodology on the basis of historical data for a power-split hybrid electric bus (HEB) is proposed in this study. This approach aims to fully utilize the fuel-saving capability of power-split HEB under real operating cycles and provide an effective way for solving the optimal calibration problem in the application promotion. Firstly, a procedure for synthesizing real-world driving cycles based on cluster analysis and Markov chain method is constructed. Subsequently, dynamic programming (DP) control algorithm is performed to explore the fuel economy potential. Moreover, a DP-based rule control strategy with an automated implementation foundation is introduced to achieve online approximate optimal effect. Finally, offline simulation and hardware-in-the-loop test are conducted. Simulation results validate that the proposed online optimal control strategy methodology has similar fuel-saving performance to DP optimal results and good real-time application conditions