Chen G.,PLA Air Force Aviation University |
Wang N.,Aeronautical Computing technique Research Institute |
Zhang F.,PLA Air Force Aviation University |
Jiang H.,PLA Air Force Aviation University
Proceedings - 2015 IEEE International Conference on Big Data, IEEE Big Data 2015 | Year: 2015
Quantitative understanding of people's behaviors on social networks has significant meaning to reveal the origins of many socioeconomic phenomena. This paper focuses on the time characteristic of human behavior online. Four famous web forums of China were analyzed, including Sina, NetEase, HuBeiDongHu and LiXiang. The empirical analysis result presents some statistical features on the behaviors of forum users. We found that the intervals of user's post and reply behaviors both follow heavy-tailed distribution and have high burstiness and low memory. But the day activities do not follow heavy-tailed distribution and the values concentrate between 10 and 100. Further, we studied the intra-day post and reply behaviors and showed that people's behaviors online have similar time characteristic with that of real life, and they submit obviously more posts and replies on work time and seldom do actions after midnight. The findings of this paper reveal some interesting features of human behaviors on online forums and are helpful to the behavior-based detection of spam and spammer. © 2015 IEEE.
Carstensen C.,Humboldt University of Berlin |
Carstensen C.,Yonsei University |
Xie X.,University of Sichuan |
Yu G.,University of Sichuan |
Zhou T.,Aeronautical Computing technique Research Institute
Computer Methods in Applied Mechanics and Engineering | Year: 2011
This paper proposes a quadrilateral finite element method of the lowest order for Reissner-Mindlin (R-M) plates on the basis of Hellinger-Reissner variational principle, which includes variables of displacements, shear stresses and bending moments. This method uses continuous piecewise isoparametric bilinear interpolation for the approximation of transverse displacement and rotation. The piecewise-independent shear stress/bending moment approximation is constructed by following a self-equilibrium criterion and a shear-stress-enhanced condition. A priori and reliable a posteriori error estimates are derived and shown to be uniform with respect to the plate thickness t. Numerical experiments confirm the theoretical results. © 2010 Elsevier B.V.
Shen Y.,Southwest University |
Fan Y.,Aeronautical Computing technique Research Institute |
Xia D.,Southwest University
ICIC Express Letters | Year: 2014
In this note, a second-order sampling sliding-mode controller is designed for the dual integral system with uncertainties. According to the quadrant location of the system phase trajectory, the controller realizes stable tracking by adjusting the switching sequence of the high and low gain. By analyzing each phase trajectory motion, the relationship between the chattering characteristic (chattering amplitude and frequency) and the control parameters of the ideal dual integral system is derived; the variation range of chattering amplitude and frequency is estimated by considering the influence of the uncertainties on chattering characteristic. In the simulation experiments, the chattering characteristic of the ideal and the uncertain dual integral system are measured and compared with the estimating results. The results show the correctness of the chattering analysis. © 2014 ICIC International.
Liang Y.,Laboratory of Test and Inspection Technology |
Meng Y.,Aeronautical Computing technique Research Institute
WIT Transactions on Information and Communication Technologies | Year: 2014
Short circuit is one of the most common failure modes of multilayer ceramic capacitor (MLCC). Here the main failure mechanism such as internal material defect, crack, and silver electrode electrical migration was analyzed firstly, which causes the MLCC short circuit. Then it gave the failure analysis process. Finally, with the result analyzed above, this paper also offers proposals for preventing MLCC short circuit in terms of production and usage. © 2014 WIT Press.
Shen Y.,Southwest University |
Fan Y.,Aeronautical Computing technique Research Institute
Applied Mechanics and Materials | Year: 2014
The influence of sliding surface on SMC design is considered. How the sliding surface affect the chattering frequency and amplitude is investigated by describing function (DF) approach. In part-state sliding surface SMC, the chattering can be changed by feedback state selection. The relationship between chattering types and initial state values is analyzed. The proposed approach is proved has sufficient accurate estimation and judgment by simulation response curves. Simulation curves show that sliding surface design plays important roles in chattering frequency and amplitude. © (2014) Trans Tech Publications, Switzerland.