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Image processing based remote control with robot arm simulator
Jiafeng. Zhang,Feifei. Zhang,Masanori. Ito 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
Motion estimation provides an attractive choice to cumbersome interface devices for human computerinteraction (HCI). Worthy of note, visual recognition of hand gestures can help achieving in an easy and natural way forinteraction between human and computer. The interfaces of HCI and other virtual reality systems depend on accurate,real-time hand and fingertip tracking for association between real objects and relative digital information. They costexpensively and complicated operations make them troublesome. We are developing a real-time, view-based gesture recognition system. Optical flow is estimated and segmented into motion fragments. Using artificial neural network (ANN), it can compute and estimate the motion of gesture. Comparing with the traditional approaches, theoretical andexperimental results show that this method has more simple hardware and algorithm demands but more effectiveness. It can be used in remote control system for understanding the human body languages.
Eigenvalue Assignment in Linear Descriptor Systems using Dynamic Compensators
Biao Zhang,Jiafeng Zhu 제어·로봇·시스템학회 2014 International Journal of Control, Automation, and Vol.12 No.5
An approach for eigenvalue assignment in strongly controllable and observable linear descriptor systems using dynamic compensators is proposed. Parametric expressions for the controller coefficient matrices are given. The approach assigns the full number of distinct finite closed-loop eigenvalues, guarantees the closed-loop regularity and overcomes the defects of some previous works. In addition, using the proposed eigenvalue assignment approach, a sufficient condition for generic eigenvalue assignability using dynamic compensators is proved.
Optimistic Fault Diagnosis in Discrete Event Systems by Labeled Petri Nets and Basis Markings
Guanghui Zhu,Jiafeng Zhang,Zhong Zheng,Shan Luan,Te Chen,Qiang Ma,Zhiwu Li 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.6
This paper deals with the fault diagnosis problem of discrete event systems modeled with labeled Petri nets. Its main contributions are threefold. First, depending on whether a diagnosis function examines the fault transitions that possibly occur after the last observed event, we formally divide the diagnosis functions into two types: optimistic and pessimistic, which aims to facilitate the exploration of different diagnosis approaches. Second, a framework is proposed, which extends a given diagnosis approach for Petri nets to the case of labeled Petri nets. The main idea of the framework is to compute and combine the diagnosis results of observable transition sequences corresponding to an observed word. Third, we convert a basis-marking-based approach that is originally pessimistic to the optimistic case and prove the correctness of this conversion.
( Changcheng Wu ),( Hao Zhang ),( Jiafeng Hua ),( Sha Hua ),( Yanyi Zhang ),( Xiaoming Lu ),( Yichen Tang ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.12
Recognizing license plate from its traffic camera captured images is one of the most important aspects in many traffic management systems. Despite many sophisticated license plate recognition related algorithms available online, license plate recognition is still a hot research issue because license plates in each country all round the world lack of uniform format and their camera captured images are often affected by multiple adverse factors, such as low resolution, poor illumination effects, installation problem etc. A novel method is proposed in this paper to solve the inclination problem of license plates in their camera captured images through four parts: Firstly, special edge pixels of license plate are chosen to represent main information of license plates. Secondly, least square methods are used to compute the inclined angle of license plates. Then, coordinate rotation methods are used to rotate the license plate. At last, bilinear interpolation methods are used to improve the performance of license plate rotation. Several experimental results demonstrated that our proposed method can solve the inclination problem about license plate in visual aspect and can improve the recognition rate when used as the image preprocessing method.
Influence of Atmospheric Turbulence Channel on a Ghost-imaging Transmission System
Wang, Kaimin,Wang, Zhaorui,Zhang, Leihong,Kang, Yi,Ye, Hualong,Hu, Jiafeng,Xu, Jiaming Optical Society of Korea 2020 Current Optics and Photonics Vol.4 No.1
We research a system of compressed-sensing computational ghost imaging (CSCGI) based on the intensity fluctuation brought by turbulence. In this system, we used the gamma-gamma intensity-fluctuation model, which is commonly used in transmission systems, to simulate the CSCGI system. By setting proper values of the parameters such as transmission distance, refractive-index structure parameter, and sampling rates, the peak signal-to-noise ratio (PSNR) performance and bit-error rate (BER) performance are obtained to evaluate the imaging quality, which provides a theoretical model to further research the ghost-imaging algorithm.
Dongwen Wang,Wei Yang,Jiafeng Yang,Kongming Jiang,Junjie Zhang,Yang Fu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.9
Research on the vibration characteristics of the permanent magnet synchronous motor (PMSM) is hindered by the harmonic characteristics of the unbalanced magnetic pull force when air-gap eccentricity is neglected. Thus, the effects of both air-gap eccentricity and mass eccentricity on the rotor vibration have not yet been fully elucidated. To address this, a unified expression for the unbalanced magnetic pull force of the motor was derived under various pole pairs and air-gap eccentricities. The distribution of the radial electromagnetic force under different eccentricities is revealed. An electromagnetic simulation model of the fan motor was established for three eccentric cases and the effect of the unbalanced magnetic pull distribution and harmonic frequency characteristics on the rotor were analyzed. Furthermore, the influence of the gyroscopic effects on the modal frequency of the rotor structure was studied. The harmonic response of the rotor shaft system was first established using multi-physical field coupling, then the vibration amplitude-frequency laws of the rotor-shaft system under the influence of air-gap eccentricity and mass eccentricity were investigated. To reduce the vibration of the unbalanced PMSM rotor-shaft system, a multi-objective optimization was performed using the genetic algorithm in ANSYS Workbench. Research on the vibration characteristics of the permanent magnet synchronous motor (PMSM) is hindered by the harmonic characteristics of the unbalanced magnetic pull force when air-gap eccentricity is neglected. Thus, the effects of both air-gap eccentricity and mass eccentricity on the rotor vibration have not yet been fully elucidated. To address this, a unified expression for the unbalanced magnetic pull force of the motor was derived under various pole pairs and air-gap eccentricities. The distribution of the radial electromagnetic force under different eccentricities is revealed. An electromagnetic simulation model of the fan motor was established for three eccentric cases and the effect of the unbalanced magnetic pull distribution and harmonic frequency characteristics on the rotor were analyzed. Furthermore, the influence of the gyroscopic effects on the modal frequency of the rotor structure was studied. The harmonic response of the rotor shaft system was first established using multi-physical field coupling, then the vibration amplitude-frequency laws of the rotor-shaft system under the influence of air-gap eccentricity and mass eccentricity were investigated. To reduce the vibration of the unbalanced PMSM rotor-shaft system, a multi-objective optimization was performed using the genetic algorithm in ANSYS Workbench. The optimization results show that when the motor rotor core is shifted 2 mm in the positive X direction and the distance between the double-row bearing and rotor core is 7 mm, the vibration acceleration amplitude is reduced by 54.9 % compared with the original model.
Influence of Atmospheric Turbulence Channel on a Ghost-imaging Transmission System
Kaimin Wang,Zhaorui Wang,Leihong Zhang,Yi Kang,Hualong Ye,Jiafeng Hu,Jiaming Xu 한국광학회 2020 Current Optics and Photonics Vol.4 No.1
We research a system of compressed-sensing computational ghost imaging (CSCGI) based on the intensity fluctuation brought by turbulence. In this system, we used the gamma-gamma intensity-fluctuation model, which is commonly used in transmission systems, to simulate the CSCGI system. By setting proper values of the parameters such as transmission distance, refractive-index structure parameter, and sampling rates, the peak signal-to-noise ratio (PSNR) performance and bit-error rate (BER) performance are obtained to evaluate the imaging quality, which provides a theoretical model to further research the ghost-imaging algorithm.
Threshold magnetoresistance in anistropic magnetic 2D transition metal dichalcogenides
Xu, Hongjun,Hsu, Ming-Chien,Fuh, Huei-Ru,Feng, Jiafeng,Han, Xiufeng,Zhao, Yanfeng,Zhang, Duan,Wang, Xinming,Liu, Fang,Liu, Huajun,Cho, Jiung,Choi, Miri,Chun, Byong Sun,Ó,Coileá,in, Cormac The Royal Society of Chemistry 2018 Journal of Materials Chemistry C Vol.6 No.12
<P>Recently many novel magnetoresistance (MR) phenomena have been reported from studies of two dimensional (2D) materials. Here, we report on the exotic transport behavior of VS2. A large negative and quadratic MR of −10% is observed for an in-plane magnetic field B up to 14 T. Remarkably, when the applied field deviates from the in-plane orientation there is a threshold field, Bc, and the MR shows a plateau of near zero MR. When B < Bc, only a single state exists and the transition between quantum spin states is forbidden. Our work sheds new light on the MR of magnetic 2D materials with localized states and may spur further investigations.</P>
A Ghost-Imaging System Based on a Microfluidic Chip
Kaimin Wang,Xiaoxuan Han,Hualong Ye,Zhaorui Wang,Leihong Zhang,Jiafeng Hu,Meiyong Xu,Xiangjun Xin,Dawei Zhang 한국광학회 2021 Current Optics and Photonics Vol.5 No.2
Microfluidic chip technology is a research focus in biology, chemistry, and medicine, for example. However, microfluidic chips are rarely applied in imaging, especially in ghost imaging. Thus in this work we propose a ghost-imaging system, in which we deploy a novel microfluidic chip modulator (MCM) constructed of double-layer zigzag micro pipelines. While in traditional situations a spatial light modulator (SLM) and supporting computers are required, we can get rid of active modulation devices and computers with this proposed scheme. The corresponding simulation analysis verifies good feasibility of the scheme, which can ensure the quality of data transmission and achieve convenient, fast ghost imaging passively.