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Guo J.,Xi'an Technological University | Liu K.,Tsinghua University | Qiu Z.,Aeronautical Computing Technique Research Institute
Revista Tecnica de la Facultad de Ingenieria Universidad del Zulia | Year: 2016

In the high AOA and post stall state, the aircraft suffers from serious nonlinear dynamic characteristics in which traditional small disturbance linearization controller design method is not applicable any more. To address this problem, a robust controller is designed via the L1 adaptive control method. The inner loop controller is designed through the use of nonlinear dynamic inversion approach while the outer loop robust controller is designed by the L1 adaptive control. The controller developed in this paper can not only overcome system model uncertainty but also avoid dynamic inverse time-scale separation problem, making the whole closed-loop performance of the system easy for analysis. Simulations are conducted to demonstrate the effectiveness of the proposed approach. © 2016, Revista Tecnica de la Facultad de Ingeniera. All rights reserved.

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.

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.

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.

Guo J.,Northwestern Polytechnical University | Zhang S.,Northwestern Polytechnical University | Qiu Z.,Aeronautical Computing Technique Research Institute
Revista Tecnica de la Facultad de Ingenieria Universidad del Zulia | Year: 2016

As a simple and effective clustering algorithm, K-means has been extensively used in the field of data mining. However, one shortage of the K-means algorithm is that it requires the selection of cluster number as well as initial cluster centers, which can sometimes impair algorithm performance if these parameters are not well selected. In order to address this problem, this paper presents an improved clustering algorithm by combining the K-means algorithm with the fuzzy matrix algorithm and applied the algorithm to the problem of user and page clustering in Web log mining. The algorithm first extracts compressed sub-matrix from relational matrix of users and Web pages, then divides all users into clusters based on their relative distances. As a result, outliers are identified and cluster number as well as cluster centers are obtained naturally. Comparison with the K-means algorithm demonstrates the superiority of the proposed algorithm. © 2016, Revista Tecnica de la Facultad de Ingeniera. All rights reserved.

Wu J.,Xidian University | Li X.,Xidian University | Jiao L.,Xidian University | Wang X.,Aeronautical Computing Technique Research Institute | Sun B.,ZTE Corporation
Physica A: Statistical Mechanics and its Applications | Year: 2013

A simple deterministic algorithm for community detection is provided by using two rounds of minimum spanning trees. By comparing the first round minimum spanning tree (1st-MST) with the second round spanning tree (2nd-MST) of the network, communities are detected and their overlapping nodes are also identified. To generate the two MSTs, a distance matrix is defined and computed from the adjacent matrix of the network. Compared with the resistance matrix or the communicability matrix used in community detection in the literature, the proposed distance matrix is very simple in computation. The proposed algorithm is tested on real world social networks, graphs which are failed by the modularity maximization, and the LFR benchmark graphs for community detection. © 2012 Elsevier B.V. All rights reserved.

Niu W.,Aeronautical Computing Technique Research Institute | Niu W.,Xidian University | Ma J.,Xidian University
ICIC Express Letters, Part B: Applications | Year: 2014

Grey theory is a truly multidisciplinary and generic theory that deals with systems that are characterized by poor information and/or for which information is lacking. However, the stability of GM(1,1) is one of the problems which has been discussed by many scholars all the time, and there is deviation in modeling method of GM(1,1). In this paper, we proved that the growth rate of the simulated value derived from GM(1,1) is a fixed value. If the growth rates of the primary sequence are equal, the fitted value deriving from GM(1,1) is the same as the primary sequence, and otherwise greater error would occur. In order to overcome disadvantage of the fixed growth rates, this paper extended the traditional GM(1,1) model. This improved model is abbreviated as EGM(1,1), which can predict more accurately on non geometric sequences. Based on the error analysis of the GM(1,1) model, a new method optimizes the background value in EGM(1,1) model. We use the data of a certain aeroengine taken as our case study to test the efficiency and accuracy of the proposed method. According to the experimental results, our proposed new method obviously can improve the prediction accuracy of the traditional grey model. © 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.

Wang X.-H.,Xidian University | Wang X.-H.,Aeronautical Computing Technique Research Institute | Jiao L.-C.,Xidian University | Wu J.-S.,Xidian University
Chinese Physics B | Year: 2010

In this paper, we propose a simple model that can generate small-world network with community structure. The network is introduced as a tunable community organization with parameter r, which is directly measured by the ratio of inter- to intra-community connectivity, and a smaller r corresponds to a stronger community structure. The structure properties, including the degree distribution, clustering, the communication efficiency and modularity are also analysed for the network. In addition, by using the Kuramoto model, we investigated the phase synchronization on this network, and found that increasing the fuzziness of community structure will markedly enhance the network synchronizability; however, in an abnormal region (r ≤ 0.001), the network has even worse synchronizability than the case of isolated communities (r 0). Furthermore, this network exhibits a remarkable synchronization behaviour in topological scales: the oscillators of high densely interconnected communities synchronize more easily, and more rapidly than the whole network. © 2010 Chinese Physical Society and IOP Publishing Ltd.

Wu J.,Xidian University | Wang X.,Aeronautical Computing Technique Research Institute | Jiao L.,Xidian University
Physica A: Statistical Mechanics and its Applications | Year: 2012

In this paper, we propose a simple random network model with overlapping communities controlled by several parameters, and investigate the influence of the overlapping community structure on the synchronization behavior under different parameters. It is found that the synchronizability of the network is mainly influenced by the overlapping size of the communities and the connectivity density of the overlapped group to the other interrelated communities, and has nothing to do with the intra-connectivity of the overlapped group. In addition, it is found that the highly interconnected communities can be almost synchronized in a given time scale, whereas the overlapped group is far from synchronization. Furthermore, the instantaneous frequencies of the nodes in the communities and their overlapped group are also investigated, which show that the nodes in the overlapped group will exhibit a remarkable oscillation with a weighted mean frequency of the other correlative communities. © 2011 Elsevier B.V. All rights reserved.

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