Existing location privacy- preserving methods, without a trusted third party, cannot resist conspiracy attacks and active attacks. This paper proposes a novel solution for location based service （LBS） in vehicular a...Existing location privacy- preserving methods, without a trusted third party, cannot resist conspiracy attacks and active attacks. This paper proposes a novel solution for location based service （LBS） in vehicular ad hoc network （VANET）. Firstly, the relationship among anonymity degree, expected company area and vehicle density is discussed. Then, a companion set F is set up by k neighbor vehicles. Based on secure multi-party computation, each vehicle in V can compute the centroid, not revealing its location to each other. The centroid as a cloaking location is sent to LBS provider （P） and P returns a point of interest （POI）. Due to a distributed secret sharing structure, P cannot obtain the positions of non-complicity vehicles by colluding with multiple internal vehicles. To detect fake data from dishonest vehicles, zero knowledge proof is adopted. Comparing with other related methods, our solution can resist passive and active attacks from internal and external nodes. It provides strong privacy protection for LBS in VANET.展开更多
In this paper, a new flux limiter scheme with the splitting technique is successfully incorporated into a multiple-relaxation-time lattice Boltzmann （LB） model for shacked compressible flows. The proposed flux limit...In this paper, a new flux limiter scheme with the splitting technique is successfully incorporated into a multiple-relaxation-time lattice Boltzmann （LB） model for shacked compressible flows. The proposed flux limiter scheme is efficient in decreasing the artificial oscillations and numerical diffusion around the interface. Due to the kinetic nature, some interface problems being difficult to handle at the macroscopic level can be modeled more naturally through the LB method. Numerical simulations for the Richtmyer-Meshkov instability show that with the new model the computed interfaces are smoother and more consistent with physical analysis. The growth rates of bubble and spike present a satisfying agreement with the theoretical predictions and other numerical simulations.展开更多
The aims of the present paper are twofold. At first, we further study the Multiple-Relaxation-Time （MRT） Lattice Boltzmann （LB） model proposed in [Europhys. Lett. 90 （2010） 54003]. We discuss the reason why the ...The aims of the present paper are twofold. At first, we further study the Multiple-Relaxation-Time （MRT） Lattice Boltzmann （LB） model proposed in [Europhys. Lett. 90 （2010） 54003]. We discuss the reason why the Gram Schmidt orthogonalization procedure is not needed in the construction of transformation matrix M; point out a reason why the Kataoka-Tsutahara model [Phys. Rev. E 69 （2004） 035701（R）] is only valid in subsonic flows. The yon Neumann stability analysis is performed. Secondly, we carry out a preliminary quantitative study on the Richtmyer- Meshkov instability using the proposed MRT LB model. When a shock wave travels from a light medium to a heavy one, the simulated growth rate is in qualitative agreement with the perturbation model by Zhang-Sohn. It is about half of the predicted value by the impulsive model and is closer to the experimental result. When the shock wave travels from a heavy medium to a light one, our simulation results are also consistent with physical analysis.展开更多
Regarding conventional quantum dot lightemitting diodes(QLEDs)fabricated by using the spin-coating(SC)technique,voids and interstitial spaces are inevitable due to unordered quantum dots(QDs)stacking,generating device...Regarding conventional quantum dot lightemitting diodes(QLEDs)fabricated by using the spin-coating(SC)technique,voids and interstitial spaces are inevitable due to unordered quantum dots(QDs)stacking,generating device leakage current under an external bias.In the present study,we fabricated an ultra-homogeneous and highly ordered QD monolayer by adopting the Langmuir-Blodgett(LB)technique.The QD monolayer was transferred as a emissive layer with a horizontal lifting(HL)method to a red QLED,which exhibited high performance with an external quantum efficiency(EQE)of 19.0% and lifetime(T_(95)@100 cd m^(-2))of13,324 h.When compared with the SC-based device,the EQE and lifetime were improved by 15% and 183% due to the compact and ordered QD monolayer that lowered the leakage current.Moreover,white QLEDs with stacked QD monolayers could be obtained at a low voltage of 4 V because LB technique is an organic-solvent-free approach avoiding interlayer mixing and controlling the QD layer thickness precisely.In addition,we successfully fabricated an ultra-homogeneous large-area QD monolayer on a rectangular substrate with a size of 9 cm×5 cm,indicating the promising size scalability of the LB-HL strategy.展开更多
基金the National Natural Science Foundation of China，by the Natural Science Foundation of Anhui Province，by the Specialized Research Fund for the Doctoral Program of Higher Education of China，the Fundamental Research Funds for the Central Universities
文摘Existing location privacy- preserving methods, without a trusted third party, cannot resist conspiracy attacks and active attacks. This paper proposes a novel solution for location based service （LBS） in vehicular ad hoc network （VANET）. Firstly, the relationship among anonymity degree, expected company area and vehicle density is discussed. Then, a companion set F is set up by k neighbor vehicles. Based on secure multi-party computation, each vehicle in V can compute the centroid, not revealing its location to each other. The centroid as a cloaking location is sent to LBS provider （P） and P returns a point of interest （POI）. Due to a distributed secret sharing structure, P cannot obtain the positions of non-complicity vehicles by colluding with multiple internal vehicles. To detect fake data from dishonest vehicles, zero knowledge proof is adopted. Comparing with other related methods, our solution can resist passive and active attacks from internal and external nodes. It provides strong privacy protection for LBS in VANET.
基金Supported by the Science Foundation of Laboratory of Computational Physics, Science Foundation of China Academy of Engineering Physics under Grant Nos. 2009A0102005, 2009B0101012National Basic Research Program of China under Grant No. 2007CB815105+1 种基金National Natural Science Foundation of China under Grant Nos. 11074300, 11075021, and 11074303the Fundamental Research Funds for the Central Universities under Grant No. 2010YS03
文摘In this paper, a new flux limiter scheme with the splitting technique is successfully incorporated into a multiple-relaxation-time lattice Boltzmann （LB） model for shacked compressible flows. The proposed flux limiter scheme is efficient in decreasing the artificial oscillations and numerical diffusion around the interface. Due to the kinetic nature, some interface problems being difficult to handle at the macroscopic level can be modeled more naturally through the LB method. Numerical simulations for the Richtmyer-Meshkov instability show that with the new model the computed interfaces are smoother and more consistent with physical analysis. The growth rates of bubble and spike present a satisfying agreement with the theoretical predictions and other numerical simulations.
基金Support by the Science Foundations of Laboratory of Computational Physics,Science Foundation of China Academy of Engineering Physics under Grant Nos.2009A0102005,2009B0101012National Basic Research Program of China under Grant No.2007CB815105National Natural Science Foundation of China under Grant Nos.11074300,11075021,and 11071024
文摘The aims of the present paper are twofold. At first, we further study the Multiple-Relaxation-Time （MRT） Lattice Boltzmann （LB） model proposed in [Europhys. Lett. 90 （2010） 54003]. We discuss the reason why the Gram Schmidt orthogonalization procedure is not needed in the construction of transformation matrix M; point out a reason why the Kataoka-Tsutahara model [Phys. Rev. E 69 （2004） 035701（R）] is only valid in subsonic flows. The yon Neumann stability analysis is performed. Secondly, we carry out a preliminary quantitative study on the Richtmyer- Meshkov instability using the proposed MRT LB model. When a shock wave travels from a light medium to a heavy one, the simulated growth rate is in qualitative agreement with the perturbation model by Zhang-Sohn. It is about half of the predicted value by the impulsive model and is closer to the experimental result. When the shock wave travels from a heavy medium to a light one, our simulation results are also consistent with physical analysis.
基金supported by the National Natural Science Foundation of China(62075043)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZZ126)。
文摘Regarding conventional quantum dot lightemitting diodes(QLEDs)fabricated by using the spin-coating(SC)technique,voids and interstitial spaces are inevitable due to unordered quantum dots(QDs)stacking,generating device leakage current under an external bias.In the present study,we fabricated an ultra-homogeneous and highly ordered QD monolayer by adopting the Langmuir-Blodgett(LB)technique.The QD monolayer was transferred as a emissive layer with a horizontal lifting(HL)method to a red QLED,which exhibited high performance with an external quantum efficiency(EQE)of 19.0% and lifetime(T_(95)@100 cd m^(-2))of13,324 h.When compared with the SC-based device,the EQE and lifetime were improved by 15% and 183% due to the compact and ordered QD monolayer that lowered the leakage current.Moreover,white QLEDs with stacked QD monolayers could be obtained at a low voltage of 4 V because LB technique is an organic-solvent-free approach avoiding interlayer mixing and controlling the QD layer thickness precisely.In addition,we successfully fabricated an ultra-homogeneous large-area QD monolayer on a rectangular substrate with a size of 9 cm×5 cm,indicating the promising size scalability of the LB-HL strategy.
