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Zheng J.-J.,Dalian Airforce Communication NCO Academy | Lin J.-L.,Xihua University | Zhu W.-L.,University of Electronic Science and Technology of China
Dianzi Keji Daxue Xuebao/Journal of the University of Electronic Science and Technology of China | Year: 2011

Time domain synchronous-orthogonal frequency-division multiplexing (TDS-OFDM) system makes used of PN sequence as guard interval, which is used as channel estimation. Because PN serial correlation is not ideal δ function, extra error has been inducted. A channel equalization method suitable for OFDM system is propose in the paper. Cepstral technique is employed in the method to attain the channel equalization. The simulation results indicate that this method has perfect equalization effect. Source

Xie J.-P.,Lanzhou University | Xie J.-P.,Dalian Airforce Communication NCO Academy | Lv W.-L.,Lanzhou University | Yang T.,Lanzhou University | And 2 more authors.
Faguang Xuebao/Chinese Journal of Luminescence | Year: 2012

Organic field-effect transistors (OFETs) based on copper phthalocyanine were fabricated and their current-voltage characteristics were measured in dark/under illumination. The results showed that OFETs with Au as source/drain electrodes exhibited a photo-current/dark-current ratio of 0.4 and a photoresponsivity of 2.55 mA/W under illumination by a laser diode with a wavelength of 655 nm and power density of 100 mW/cm 2; however, OFETs with Al as source/drain electrodes exhibited a photo-current/dark-current ratio up to 10 4 and a much lower photoresponsivity of 0.39 mA/W under the same conditions. The tremendous increase of photo-current/dark-current ratio is ascribed to the decrease of dark-current caused by Schottky contacts between Al source/drain electrodes and CuPc. Source

Liu Y.,Tsinghua National Laboratory for Information Sciences and Technology | Liu Y.,Dalian Airforce Communication NCO Academy | Zhong X.,Tsinghua National Laboratory for Information Sciences and Technology | Wang J.,Tsinghua National Laboratory for Information Sciences and Technology
2016 23rd International Conference on Telecommunications, ICT 2016 | Year: 2016

In the multiuser cooperative communication, a core problem is how to efficiently find an appropriate cooperative relay node with lower power consumption and minimal payment when the number of relay nodes is large. This is referred to as optimal relay selection problem, which characterize the desired tradeoff between the probing cost for establishing cooperative transmission and the reward via the cooperative diversity. In this paper, we establish optimal strategies for the homogenous relay node and heterogenous relay node by using optimal stopping theory with a finite horizon. Furthermore, for the homogenous and heterogenous case, the optimal strategies exhibit a pure SNR threshold structure and reward threshold structure, respectively. Therefore, they are simple to be implemented. Theoretical analysis and numerical results indicate that the proposed optimal relay selection strategies can reduce the number of probing candidate relays and improve the transmission rate with lower energy consumption and minimal payment. © 2016 IEEE. Source

Yin X.,PLA Air Force Aviation University | Liu Y.,PLA Air Force Aviation University | Fang Y.,Dalian Airforce Communication NCO Academy
Proceedings - 2014 IEEE Workshop on Advanced Research and Technology in Industry Applications, WARTIA 2014 | Year: 2014

Problem of intranet security is almost birth with network interconnection, especially when the demand for network interconnection is booming throughout the world. The traditional technology can't guarantee the access terminals to its safe and reliable. In view of this, this paper introduces the trustworthiness evaluation technology in trusted computing. The collection and management model is established to deal with the evidences. Through analysing access terminals' own environment and behavior this paper puts forward a model of trust evaluation of tree type, and focuses on the analysis of decision attributes in the model. The model uses multi dimension attributes to determine the trusted access. Finally, the assessment model is analyzed and validated through a simulation experiment, and the results show that the evaluation model is feasible and effectiveness. © 2014 IEEE. Source

Liu Y.,LIAONING Technical University | Zhang X.,Jilin University | Liu D.,Dalian Ocean University | Zhiqiang H.,Dalian Airforce Communication NCO Academy
Advanced Materials Research | Year: 2013

The TDOA localization algorithm for wireless sensor networks can help us measure thetime differences of an unknown node to more anchor nodes, which establish nonlinear equation ofthe differential distance between unknown node and anchor node. Newton iteration is the crucialmethod for nonlinear equation numerical solutions, so using the Newton iterative method can betterachieve nonlinear optimization in TDOA location. The simulation results indicate that the algorithmcan meet the requirement of localization and possesses the preferable localization precision. © (2013) Trans Tech Publications, Switzerland. Source

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