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RISS 인기검색어
- 검색키워드
- 저자 : Dandan Ke (검색결과 5 건)
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Secure Beamforming with Artificial Noise for Two-way Relay Networks
( Dandan Li ),( Ke Xiong ),( Guanyao Du ),( Zhengding Qiu ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.6
This paper studies the problem of secure information exchange between two sources via multiple relays in the presence of an eavesdropper. To this end, we propose a relay beamforming scheme, i.e., relay beamforming with artificial noise (RBwA), where the relay beamforming vector and the artificial noise vector are jointly designed to maintain the received signal-to-interference-ratio (SINR) at the two sources over a predefined Quality of Service (QoS) threshold while limiting the received SINR at the eavesdropper under a predefined secure threshold. For comparsion, the relay beamforming without artificial noise (RBoA) is also considered. We formulate two optimization problems for the two schemes, where our goal is to seek the optimal beamforming vector to minimize the total power consumed by relay nodes such that the secrecy of the information exchange between the two sources can be protected. Since both optimization problems are nonconvex, we solve them by semidefinite program (SDP) relaxation theory. Simulation results show that, via beamforming design, physical layer secrecy of two-way relay networks can be greatly improved and our proposed RBwA outperforms the RBoA in terms of both low power consumption and low infeasibility rate.
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SER-Based Relay Selection for Two-Way Relaying with Physical Layer Network Coding
Dandan Li,Ke Xiong,Zheng-ding Qiu,Guanyao Du 한국전자통신연구원 2013 ETRI Journal Vol.35 No.2
To enhance the symbol error rate (SER) performance of the two-way relay channels with physical layer network coding, this letter proposes a relay selection scheme, in which the relay with the maximal minimum distance between different points in its constellation among all relays is selected to assist two-way transmissions. We give the closed-form expression of minimum distance for binary phase-shift keying and quadrature phaseshift keying. Additionally, we design a low-complexity method for higher-order modulations based on look-up tables. Simulation results show that the proposed scheme improves the SER performance for two-way relay networks.
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A simple data assimilation method to improve atmospheric dispersion based on Lagrangian puff model
Li, Ke,Chen, Weihua,Liang, Manchun,Zhou, Jianqiu,Wang, Yunfu,He, Shuijun,Yang, Jie,Yang, Dandan,Shen, Hongmin,Wang, Xiangwei Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.7
To model the atmospheric dispersion of radionuclides released from nuclear accident is very important for nuclear emergency. But the uncertainty of model parameters, such as source term and meteorological data, may significantly affect the prediction accuracy. Data assimilation (DA) is usually used to improve the model prediction with the measurements. The paper proposed a parameter bias transformation method combined with Lagrangian puff model to perform DA. The method uses the transformation of coordinates to approximate the effect of parameters bias. The uncertainty of four model parameters is considered in the paper: release rate, wind speed, wind direction and plume height. And particle swarm optimization is used for searching the optimal parameters. Twin experiment and Kincaid experiment are used to evaluate the performance of the proposed method. The results show that the proposed method can effectively increase the reliability of model prediction and estimate the parameters. It has the advantage of clear concept and simple calculation. It will be useful for improving the result of atmospheric dispersion model at the early stage of nuclear emergency.
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Xin Zhao,Dandan Ke,Shumin Han,Yuan Li,Hongming Zhang,Ying Cai 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.11
By adding surfactant polyvinyl alcohol (PVA) and controlling the preparation process, we successfully synthesized Co–Mo catalysts. For further improving the dispersion, reduced graphene oxide sheets as catalyst carrier were introduced to synthesize Co–Mo@rGO composite catalyst as highly efficient catalysts for hydrolytic dehydrogenation of ammonia borane. The introduction of Mo for preparing Co–Mo@rGO catalyst helped to form alloy catalyst with better structure, better dispersity and smaller particle size. When the molar ratio of Co and Mo was 0.75 : 0.25, the bimetallic composite catalyst exhibited superior activity with TOF value of 16.29 mol H2 · min -1 · mol Co-Mo -1. The activation energy of the reaction was calculated to be 43.72 kJ · mol -1. Furthermore, the reusability tests reveal that waxberry-like Co–Mo still show good catalytic activity with 80.3 % of their initial activity in five successive runs. The enhanced catalytic activities were due to the synergistic interaction between graphene sheets and waxberry-like Co–Mo NPs, which was beneficial to improve the dispersion and stability of bimetallic NPs. Also, ligand effects on the formation of waxberry-like structure and amorphous state further promoted the catalytic activity.
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Transmission Power Minimization with Network Coding for Mobile Terminals in Cellular Relay Networks
( Guanyao Du ),( Ke Xiong ),( Dandan Li ),( Zhengding Qiu ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.9
This paper jointly investigates the bandwidth allocation, transmission strategy and relay positions for two-way transmission aware cellular networks with network coding (NC). Our goal is to minimize the transmission power of mobile terminals (MTs). Consider a cellular system, where multiple MTs exchange information with their common base station, firstly, we propose an efficient bandwidth allocation method and then give a transmission strategy for each MT to determine whether to use relay stations (RSs) for its two-way transmission with the BS or not. To further improve the system performance, the optimal positions of RSs are also jointly discussed. A GA-based algorithm is presented to obtain the optimum positions for RSs. Besides, the impacts of frequency reuse on MT`s transmission power and system spectral efficiency (SE) under different number of relays are also discussed in our work. Numerical results show that the proposed NC aware scheme can extend MTs` battery life at least 6% more than traditional method.
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