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Wenhui Li,Shaoxue Jing,Bin Yang 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.10
Time delay dynamic systems are widely existed due to sensors, actuators or other reasons. In this paper, a time delay FIR system is considered to model linear dynamic systems. The reason why the FIR model is selected is to highlight the proposed time-delay estimation method and parameter identification algorithm, and avoid the impact of a complex model on readers’ understanding of the proposed technologies. Firstly, to obtain an estimate of the time delay, a dependence measure based method is proposed. Unlike the optimization method that requires the parameter estimate and needs to round the estimated delay, the delay estimation method based on the 2-copula dependence measure can give accurate delay estimates independently of the parameters and without rounding. Secondly, to estimate the parameters, a variable stacking length multi-gradient identification algorithm is studied. The multi-gradient technique takes recent several gradients to accelerate the stochastic gradient algorithm. The stacking length, i.e., the number of gradients used in each iteration, is determined by the Wolfe-Powell criterion. The effectiveness is tested by numerical simulations and case study.
Face Recognition based on Weber Symmetrical Local Graph Structure
( Jucheng Yang ),( Lingchao Zhang ),( Yuan Wang ),( Tingting Zhao ),( Wenhui Sun ),( Dong Sun Park ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.4
Weber Local Descriptor (WLD) is a stable and effective feature extraction algorithm, which is based on Weber's Law. It calculates the differential excitation information and direction information, and then integrates them to get the feature information of the image. However, WLD only considers the center pixel and its contrast with its surrounding pixels when calculating the differential excitation information. As a result, the illumination variation is relatively sensitive, and the selection of the neighbor area is rather small. This may make the whole information is divided into small pieces, thus, it is difficult to be recognized. In order to overcome this problem, this paper proposes Weber Symmetrical Local Graph Structure (WSLGS), which constructs the graph structure based on the 5 × 5 neighborhood. Then the information obtained is regarded as the differential excitation information. Finally, we demonstrate the effectiveness of our proposed method on the database of ORL, JAFFE and our own built database, high-definition infrared faces. The experimental results show that WSLGS provides higher recognition rate and shorter image processing time compared with traditional algorithms.
Dynamic Compression Behavior of a Mg–Gd-Based Alloy at Elevated Temperature
Changping Tang,Kai Wu,Wenhui Liu,Di Feng,Guoliang Zuo,Wuying Liang,Yue Yang,Xu Chen,Quan Li,Xiao Liu 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.6
The dynamic compression behavior and microstructure evolution at 400 °C of an extruded Mg–8Gd–4Y–Nd–Zr alloy withdifferent tempers were investigated. The peak-aged samples exhibit the highest compressive strength, followed by as-extrudedsamples and over-aged samples. The highest dynamic compressive strength of 582 MPa was achieved by peak-aged samplecompressed at 1224 s−1. The high strength was attributed to the formation of abundant thermally stable βʹ precipitates andsome dynamic precipitates. The dynamic compressive strength of peak-aged sample and over-aged sample is not sensitiveto strain rates, while that of the as-extruded sample is sensitive to strain rates. The dynamic compressive strength of the asextrudedalloy can reach 535 MPa when compressed at 2024 s−1. The high strength was mainly ascribed to the formationof numerous dynamic precipitates and the work hardening effect caused by dislocations. The cracks are composed of crackthat is 45° to loading direction on the cylindrical surface and crack on the compressed surface. Microstructure observationindicates that the crack was easily propagated along the interface between the adiabatic shear band and matrix, grainboundaries. The equilibrium phase β in over-aged sample was unable to hinder the crack propagation.
Target alignment method of inertial confinement fusion facility based on position estimation
Lin Weiheng,Zhu Jianqiang,Liu Zhigang,Pang Xiangyang,Zhou Yang,Cui Wenhui,Dong Ziming 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.10
Target alignment technology is one of the most critical technologies in laser fusion experiments and is an important technology related to the success of laser fusion experiments. In this study, by combining the open-loop and closed-loop errors of the target alignment, the Kalman state observer is used to estimate the position of the target, which improves the observation precision of the target alignment. Then the optimized result is used to guide the alignment of the target. This method can greatly optimize the target alignment error and reduce uncertainty. With the improvement of the target alignment precision, it will greatly improve the reliability and repeatability of the experiments’ results, thereby improving the success rate of the experiments.
The quorum sensing regulator OpaR is a repressor of polar flagellum genes in Vibrio parahaemolyticus
Renfei Lu,Junfang Sun,Yue Qiu,Miaomiao Zhang,Xingfan Xue,Xue Li,Wenhui Yang,Dongsheng Zhou,Lingfei Hu,Yiquan Zhang 한국미생물학회 2021 The journal of microbiology Vol.59 No.7
Vibrio parahaemolyticus possesses two types of flagella: asingle polar flagellum (Pof) for swimming and the peritrichouslateral flagella (Laf) for swarming. Expression of Lafgenes has previously been reported to be regulated by the quorumsensing (QS) regulators AphA and OpaR. In the presentstudy, we showed that OpaR, the QS regulator at high cell density(HCD), acted as a negative regulator of swimming motilityand the transcription of Pof genes in V. parahaemolyticus. OpaR bound to the promoter-proximal DNA regionsof flgAMN, flgMN, and flgBCDEFGHIJ within the Pof geneloci to repress their transcription, whereas it negatively regulatesthe transcription of flgKL-flaC in an indirect manner. Thus, this work investigated how QS regulated the swimmingmotility via direct action of its master regulator OpaR onthe transcription of Pof genes in V. parahaemolyticus.
MediaCloud: A New Paradigm of Multimedia Computing
( Wen Hui ),( Chuang Lin ),( Yang Yang ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.4
Multimedia computing has attracted considerable attention with the rapid growth in the development and application of multimedia technology. Current studies have attempted to support the increasing resource consumption and computational overhead caused by multimedia computing. In this paper, we propose MediaCloud, a new multimedia computing paradigm that integrates the concept of cloud computing in handling multimedia applications and services effectively and efficiently. MediaCloud faces the following key challenges: heterogeneity, scalability, and multimedia Quality of Service (QoS) provisioning. To address the challenges above, first, a layered architecture of MediaCloud, which can provide scalable multimedia services, is presented. Then, MediaCloud technologies by which users can access multimedia services from different terminals anytime and anywhere with QoS provisioning are introduced. Finally, MediaCloud implementation and applications are presented, and media retrieval and delivery are adopted as case studies to demonstrate the feasibility of the proposed MediaCloud design.