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Deformation analysis of a 3-DOF parallel manipulator with one or two additional branches
Chen, Xiaolei,Wu, Jun,Yu, Guang,Wang, Liping Techno-Press 2014 Advances in robotics research Vol.1 No.2
Redundant parallel manipulators have some advantages over the nonredundant parallel manipulators. It is important to determine how many additional branches should be introduced. This paper studies whether one or two additional branches should be added to a 3-DOF parallel manipulator by comparing the flexible deformation of a 3-DOF parallel manipulator with one additional branch and that with two additional branches. The kinematic and dynamic models of the redundant parallel manipulator are derived and the flexible deformation is investigated. The flexible deformation of the manipulators with one additional branch and two branches is simulated and compared. This paper is helpful for designers to design a redundantly actuated parallel manipulator.
XIAOLEI SI,GUANGLIANG CHEN,Zhili Chen,JUN HUANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.8
In this paper, a highly catalytic and nanosized Ag/Co3O4 composite for rhodamine B (RhB) degradation was fabricated by using the co-precipitation method at room temperature. The Ag/Co3O4 structure and catalytic properties were characterized through scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) gassorption measurements, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-Vis spectroscopy. The results showed that the Co3O4 nanosheets prepared by hydrothermal synthesis mainly exposed (2 2 0) and (1 1 1) facets, which played an important role in determining its catalytic oxidation performance. The Co3O4 nanosheets doped with Ag nanoparticles by a simple silver-mirror reaction exhibited a stable and well-dispersed property in dye solution. Compared to the Ag and Co3O4 nanostructure, the Ag nanoparticles with bigger diameter (10 nm) on Co3O4 surface also readily produced surface-active oxygen species and exhibited a higher catalytic activity for the degradation of RhB solution (5 mg·L-1) under the visible light. The kinetic constant K of Ag/Co3O4 catalyst for RhB degradation reaction was evaluated to0.02724 min-1, which is relatively higher than those reported in the literatures.
Adaptive Sampling for Low Power Mobile Sign Language Video Communication
Xiaolei Chen,Aihua Zhang,Xinzhu Yang 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.12
In this paper, we propose an adaptive sampling technique that achieves considerable energy savings while maintaining the required intelligibility level for mobile sign language video communication. The adaptive sampling scheme adjusts the sampling rate of the camera sensors dynamically according to the properties of sign language video communication and available battery power of mobile devices. Experimental results show that this adaptive scheme performs better than continuous sensing scheme in balancing the energy- intelligibility tradeoffs.
GUANGLIANG CHEN,FEI XUE,ZHILI CHEN,XIAOLEI SI,JUN HUANG,XU ZHENG,SYLVAIN MASSEY 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.3
In this paper, homogenous gold nanoparticles (AuNPs) with a high density and a narrow sizedistribution were successfully fabricated on titanate nanowires (TNWs) sca®olds in the absenceof organic capping agents. An ameliorated low-temperature hydrothermal method was used toprepare the TNWs sca®olds like bird's nest on the Ti substrate, and the nanowires diameter wasabout 30 – 80nm. Then, AuNPs were synthesized on the TNWs sca®olds with a deposition –precipitation urea (DPU) method. The TEM and XRD measurements indicated that well-crys-tallized face-centered cubic (fcc) AuNPs were homogeneously dispersed on TNWs, and AuNPswith average sizes of 2.7 nm and 4 nm were obtained, respectively for the theoretical gold loading5 wt.% and 8 wt.%. Inspiringly, the 8%-AuNPs/TNWs catalyst could reduce 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) within 210 s, and exhibited better catalytic reduction performancethan that of 5%-AuNPs/TNWs.
Robust Backup Path Selection in Overlay Routing with Bloom Filters
( Xiaolei Zhou ),( Deke Guo ),( Tao Chen ),( Xueshan Luo ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.8
Routing overlay offers an ideal methodology to improve the end-to-end communication performance by deriving a backup path for any node pair. This paper focuses on a challenging issue of selecting a proper backup path to bypass the failures on the default path with high probability for any node pair. For existing backup path selection approaches, our trace-driven evaluation results demonstrate that the backup and default paths for any node pair overlap with high probability and hence usually fail simultaneously. Consequently, such approaches fail to derive a robust backup path that can take over in the presence of failure on the default path. In this paper, we propose a three-phase RBPS approach to identify a proper and robust backup path. It utilizes the traceroute probing approach to obtain the fine-grained topology information, and systematically employs the grid quorum system and the Bloom filter to reduce the resulting communication overhead. Two criteria, delay and fault-tolerant ability on average, of the backup path are proposed to evaluate the performance of our RBPS approach. Extensive trace-driven evaluations show that the fault-tolerant ability of the backup path can be improved by about 60%, while the delay gain ratio concentrated at 14% after replacing existing approaches with ours. Consequently, our approach can derive a more robust and available backup path for any node pair than existing approaches. This is more important than finding a backup path with the lowest delay compared to the default path for any node pair.
Reliable Localization for Wireless Sensor Networks in Complex Environments
Xiaolei Liu,Yongji Ren,Xuguang Xin,Liping Zhang,Jixiang Chen 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.10
Although localization has been widely studied for Wireless Sensor Networks (WSNs), the complex environments and the large network scale pose severe challenges and make it necessary to develop new reliable localization algorithms. In this paper, we propose a novel Multi-Hop Localization Algorithm for large-scale WSNs in complex environments. This work is based on the consideration that the localization process would encounter several kinds of adverse factors with different nature at the same time (e.g. anisotropic network characteristics, ranging uncertainty, link quality of multihop paths, etc.), which lead to obvious degradation of localization performance. Unlike most of the existing schemes, we transform the localization problem in complex environments into a hybrid constraint satisfaction problem (CSP) which is composed of three different kinds of constraints, i.e. spatial constraint, network situation constraint, and confidence constraint. Set-membership approach and interval analysis method have been utilized to deal with the CSP and determine the positions of sensor nodes. Simulation results show that our scheme is an effective and efficient approach to localization in large-scale WSNs.