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In this paper a combined controller composed of the H∞ virtual controller and the sliding mode controller is proposed to improve the rigid spacecraft robustness. Considering the strong nonlinearity of the spacecraft dynamics, tensor product (TP) transformation is applied on the linear parameter varying (LPV) model which is obtained from the attitude kinematics system. The TP-based H∞ controller can...
For distributed generation (DG) network, it is important to estimate the real-time states. The information-centric networking (ICN) is established to take charge of the communication of DG network. However, the assumption of ideal communication between sensors and the estimation center cannot be guaranteed due to the communication constraints of ICN with the increasing DG network. A conventional algorithm,...
An integrated simulation system is proposed in the paper, which considers the universal runtime platform environment, the resource management mechanism, and the aerospace oriented model software framework. The platform is compatible with the HLA protocol and support both synchronous and asynchronous modes for data interaction. The simulation execution is established on the specifically formulated...
Considering the momentum singularity characteristics, an integrated control strategy for the control moment gyros based attitude control systems is proposed, in which the angular momentum conservation between the spacecraft and the CMG is utilized to improved the system performance both in the closed loop responsiveness and the singularity controllability. The moment exchange capability of the CMGs...
A wideband dual-polarized antenna excited by T-shaped microstrip feedline for Long Term Evolution (LTE) communication system is presented. The VSWR less than 1.5, isolation between the two input ports more than 30dB, gain more than 9 dBi, and stable radiation patterns, low cross-polarization ratio, low backlobe radiation are obtained in the entire operating frequency band from 1.7 to 2.7 GHz.
A near minimum time feedback control law is proposed for the agile satellite attitude control system. The real time controller is formed by specially designed cascaded subunits. Based on this, the rapid attitude maneuvering can be applied in tasks including the move to move case. The near optimal property of that is guaranteed by the rapid dynamic response with a modified bang-bang control logic while...
A wideband dual-polarized antenna for LTE (Long Term Evolution) communication system is presented. The antenna is excited by inverted L-shaped strip feed line. A wide impedance bandwidth operating from the frequency 1.71GHz to 2.69 GHz with Voltage Standing Wave Ratio(VSWR) less than 1.5 is achieved. The isolation of the antenna between the two input ports is over 40dB. Stable radiation patterns with...
In order to get reach zone and view scope with complete geometric information to facilitate research of collision detection, a point by point scanning algorithm was brought up to generate the spatial surface of human's reach and view area. The method to set scanning point's motion path in the beginning based on the major degrees of freedom of human's arm and the range of human's eye joints in horizontal...
Organization of training data is a difficult problem in Virtual Maintenance Training. For the reusing of training information data and materials, we integrated VMT data into SCORM and S10001D standards, built a new information models and data standards. We followed the CAM of SCORM to organize and manage the VMT SCO, produced VMT SCO from S1000D data. The VMT SCO is composed of six kinds of information...
This paper proposes that box-counting dimension method be adopted for the analysis of edge images detected with classical edge detectors. By using this method, the authors find that the number of ln(N(l)) and ln(l) of binary image is greater than that of edge images; and at the resolution of 512??512 in pixel, ln(N(l)) and ln(l) of the edges images is more disorder than that of binary images when...
This paper proposes that multifractal analysis method be adopted for the analysis of edge images detected with classical edge detectors. We analyze the direct multifractal analysis method based on box-counting method with experimental images, and determine the value of f(q) and a(q). By using this method, we find that the edge images detected by difference edge detectors are similar, but, the multifractal...
This paper describes the realization of a kind of wireless data acquisition system based on nRF24E1. In this system, data acquired from sensor modules, through the wireless transceiver of the terminal, which adopts the mode of ShockBurst??, transmit to the host server and then send to the computer. The data can be analyzed by developing computer software. Through establishing communication protocols...
This paper presents a novel semi-fragile watermarking scheme for image authentication and tamper detection. The proposed scheme extracts content-based image features from the approximation subband in the wavelet domain to generate two complementary watermarks. Specifically, we generate an edge-based watermark sequence to detect any changes after manipulations. This edge-based watermark encodes the...
Ontology as the hot point in information field, it is always discussed and researched widely in the academic area. The research of converting thesaurus to ontology is going on for many years. In this paper, we mainly discussed the relationship between thesaurus and ontology, and the application of thesaurus in building ontology. The four essential elements relating to ontology research are also mentioned...
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