Nanjing, China
Nanjing, China

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Gong K.,SoutheastUniversity | Chen Z.N.,National University of Singapore | Chen Z.N.,Agency for Science, Technology and Research Singapore | Qing X.,Institute for Infocomm Research | And 3 more authors.
IEEE Transactions on Antennas and Propagation | Year: 2013

An empirical formula of the dominant mode resonant frequency of the cavity which is used to back a wide slot antenna is presented. The antenna is formed by etching a wide slot onto the broad wall of a substrate integrated waveguide (SIW) cavity fed by an SIW through an inductive coupling window. The widely slotted cavity resonates at the dominant mode when the wide slot radiates. Based on the analysis of the field distribution in the slotted-cavity, an empirical formula is derived to determine the dominant mode resonant frequency of the cavity with respect to the width to length ratio (WLR) of the etched slot. The empirical formula is numerically verified at a 60-GHz band. © 2012 IEEE.


Chen C.L.P.,University of Macau | Ren C.-E.,University of Macau | Du T.,SoutheastUniversity
IEEE Transactions on Fuzzy Systems | Year: 2016

In this paper, the consensus tracking control problem of second-order multiagent systems with unknown nonlinear dynamics, immeasurable states, and disturbances is investigated. The nonlinear dynamics in multiagent systems do not satisfy the matched condition. In this paper, fuzzy logic system is introduced to approximate the unknown nonlinear dynamics, and adaptive high-gain observer is designed to estimate the unmeasured states. Based on backstepping approach and Lyapunov theory, a new adaptive fuzzy distributed controller is proposed for each agent only using the information of itself and its neighbors. Then the consensus tracking is achieved under the designed distributed controller. Moreover, it is proved that all the signals in the multiagent systems are semiglobally uniformly ultimately bounded, and the consensus tracking error converges to a small neighborhood of the origin that can be designed as small as possible. Finally, the simulation result illustrates the effectiveness of the designed controller. © 2015 IEEE.


Huang C.-T.,University of Southern California | Huang L.,Loyola Marymount University | Qin Z.,SoutheastUniversity | Yuan H.,University of Southern California | And 3 more authors.
APSIPA Transactions on Signal and Information Processing | Year: 2014

Cloud Computing has become a well-known primitive nowadays; many researchers and companies are embracing this fascinating technology with feverish haste. In the meantime, security and privacy challenges are brought forward while the number of cloud storage user increases expeditiously. In this work, we conduct an in-depth survey on recent research activities of cloud storage security in association with cloud computing. After an overview of the cloud storage system and its security problem, we focus on the key security requirement triad, i.e., data integrity, data confidentiality, and availability. For each of the three security objectives, we discuss the new unique challenges faced by the cloud storage services, summarize key issues discussed in the current literature, examine, and compare the existing and emerging approaches proposed to meet those new challenges, and point out possible extensions and futuristic research opportunities. The goal of our paper is to provide a state-of-the-art knowledge to new researchers who would like to join this exciting new field. © The Authors, 2014.


Cheng Y.Y.,SoutheastUniversity | Xia Q.,SoutheastUniversity | Zhang J.,SoutheastUniversity
SHMII 2015 - 7th International Conference on Structural Health Monitoring of Intelligent Infrastructure | Year: 2015

Development of the novel long-gauge fiber optic sensor provides an excellent opportunity for structural change localization because it measures averaged strains over a long gauge length. A practical structural change localization procedure using long-gauge dynamic strains in the modal space is proposed to process the ambient vibration data of a steel stringer bridge. The proposed procedure is easy to execute by general bridge engineers, meanwhile it has solid theory basis guaranteeing its effectiveness. By theoretically deriving the magnitude ratios between the analytical strain Frequency Response Functions (FRFs) and the estimated strain FRFs from ambient vibration data, it is proved that the proposed procedure is same as using long-gauge strain mode shapes for change location, thus it is effective and it is much simpler and easier for general bridge engineers to use. Ambient vibration test of a steel stringer bridge using long-gauge fiber optics sensors has been performed. The results of applying the proposed method to the measured and simulated data of the bridge have successfully verified its effectiveness for structural change localization. © 2015, International Society for Structural Health Monitoring of Intelligent Infrastructure, ISHMII. All rights reserved.


Li P.J.,SoutheastUniversity | Li P.J.,Polytechnic University of Turin | Zhang J.,SoutheastUniversity | Zhang J.,Polytechnic University of Turin | And 2 more authors.
SHMII 2015 - 7th International Conference on Structural Health Monitoring of Intelligent Infrastructure | Year: 2015

Various kinds of uncertainty included in the monitoring data induce the classic non-uniqueness problem during finite element (FE) calibrating. Namely, multiple models with different intrinstic parameters may fit the measurement well thus the selected single "best" model may be not a truly good model to reflect structural intrinstic property. A probability-based method using a population of FE models, not the single "best" method, is proposed to deal with the above descriped problem. In the proposed method, the Markov Chain Monte Carlo technique is first performed to sample the key structural parameters representing main sources of uncertainty. Then a population of models is generated using the samples, and the posterial probability of each model is evaluated by calculating the correlation between its simulation results and measurements through the Bayesian interface. Finally, all those FE models from the stothestic sampling with their posterial probabilities are used for structural identification and performance evaluation. The advantage of the proposed method is that it not only identifies the magnitudes of structural parameters, but also output their probability distributions, thus they are appropriate for subsequent probability-based reliability analysis and risk evaluation. This feature provided by stothestic samping and statistical techniques offter the proposed method the merit to deal with the uncertainty. The example of the Phase I IASC-ASCE benchmark structure investigated successfully verified the effectiveness of the proposed method for probability-based strucrual health monitoring. © 2015, International Society for Structural Health Monitoring of Intelligent Infrastructure, ISHMII. All rights reserved.


Zhang Y.,SoutheastUniversity | Jia C.,SoutheastUniversity | Xu Z.,SoutheastUniversity | Wang K.,SoutheastUniversity | Pei W.,SoutheastUniversity
2011 International Conference on Wireless Communications and Signal Processing, WCSP 2011 | Year: 2011

According to the correlation between adjacent blocks of the carrier image, two algorithms, called STDM-CO-MW and STDM-PCO-MW, are proposed. By using the quantization step calculated from the previous secondary block to modulate the latter secondary block, STDM-CO-MW solves the problem of the difference of quantization step between embedding and decoding. In order to raise the correlation between adjacent secondary blocks, STDM-PCO-MW exchanges the pixels between the previous secondary block and the latter one before embedding. As a result STDM-PCO-MW is more robust. Thanks to the quantization step calculated above based on modified Watson model, we find that the quantization step of our algorithms varies linearly with the brightness of the carrier image adaptively. From the results of numerical simulation, it is obvious that our proposed algorithms are robust to JPEG compression, Gaussian noise and gain attack. Compared with AQIM and general STDM based on Watson model, our algorithms have a great improvement in performance. © 2011 IEEE.


Li S.,SoutheastUniversity | Li J.,SoutheastUniversity
European Physical Journal B | Year: 2016

This paper investigates the impact of social network structures of depositors on bankruns. The analyzed network structures include random networks, small-world networks andscale-free networks. Simulation results show that the probability of bank run occurrencein random networks is larger than that in small-world networks, but the probability ofbank run occurrence in scale-free networks drops from the highest to the lowest among thethree types of network structures with the increase of the proportion of impatientdepositors. The average degree of depositor networks has a significant impact on bankruns, but this impact is related to the proportion of impatient depositors and theconfidence levels of depositors in banks. © 2016, EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


Yin G.,SoutheastUniversity | Wu H.,SoutheastUniversity | Jin X.,SoutheastUniversity
Proceedings of the 28th Chinese Control and Decision Conference, CCDC 2016 | Year: 2016

Most of the methods about designing controllers introduced for four-wheel-steer (4WS) and four-wheel-drive (4WD) vehicles are derived with the assumption that the controller parameters are constant. However, in the running process of the actual system, because of word length, conversion accuracy, truncation error of numerical calculation and other factors, the parameters of controller are often fluctuant. The existing design methods of robust controller such as H2, H∞ and μ-synthesize are extremely sensitive to perturbations of controller parameters. Therefore, the robust non-fragile controller is designed in the condition that uncertainties of the system and the controller are all taken into consideration in order to solve above-mentioned problem by using linear matrix inequality (LMI). Using non-fragile controller, the outputs of vehicle system can maintain stable state even if perturbations of controller exist in the vehicle system and the robustness of non-fragile controller is significantly better than that of fragile controller. Effectiveness of H∞ non-fragile controller is verified in SIMULINK. © 2016 IEEE.


In this paper, we demonstrate our ability to directly probe the molecular structures of the buried polymer/metal interface using sum frequency generation (SFG) vibrational spectroscopy. Spectroscopic data from different experimental approaches were compared and analyzed to deduce the molecular ordering information at a buried polymer/metal interface, i.e. the poly(n-butyl methylacrylate) (PBMA)/silver (Ag) interface. Solid spectroscopic evidence suggested that we successfully detected the molecular vibrational signals generated from the buried PBMA/Ag interface. It was found that the side butyl methyl groups at the PBMA/Ag interface are polar-ordered and have different orientational ordering from those at the PBMA surface in air. We believe that this study will provide a useful experimental and analytical framework for the SFG spectroscopy to probe the buried polymer/metal interfaces in the future.

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