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Li J.,Beijing University of Posts and Telecommunications | Jin H.,Beijing University of Posts and Telecommunications | Jing B.,Beijing University of Posts and Telecommunications | Jing B.,Beijing Institute of Applied Meteorology
China Communications | Year: 2011

In order to transmit the secure messages, a deterministic secure quantum direct communication protocol, called the "Ping-pong" protocol was proposed by Bostrom andFelbinger [Phys. Rev. Lett. 89, 187902 (2002)]. But the protocol was proved to have many vulnerabilities, and can be attacked by eavesdroppers. To overcome the problem, an improved security detection strategy which inserts the |0,|l),|+, and |-, particles into the messages as the decoy particles randomly in the "Ping-pong" protocol is presented. During the security analysis, the method of the entropy theory is introduced, and three detection strategies are conpared quantitatively by using the constraint between the information which eavesdroppers can obtain and the interference introduced. Because of the presence of the trap particles | +, and | -, the detection rate will be no less than 25% when Eve attacks the communication., The security analysis result shows that the efficiency of eavesdropping detection in the presented protocol is higher than the other two, so the detection strategy in the protocol can ensure that the "Ping-pong" protocolis more secure.


Jian L.,Beijing University of Posts and Telecommunications | Jin H.F.,Beijing University of Posts and Telecommunications | Jing B.,Beijing University of Posts and Telecommunications | Jing B.,Beijing Institute of Applied Meteorology
Science China: Physics, Mechanics and Astronomy | Year: 2011

In order to transmit the secure message, a deterministic secure quantum direct communication protocol which was called "Ping-pong" protocol was proposed by Boström and Felbinger [Boström K, et al. Phys Rev Lett, 2002, 89: 187902]. But the protocol was proved very vulnerable, and can be attacked by an eavesdropper. An improved "Ping-pong" protocol is presented to overcome the problem. The GHZ state particles are used to detect eavesdroppers, and the classical XOR operation which serves as a one-time-pad is used to ensure the security of the protocol. During the security analysis, the method of the entropy theory is introduced, and three detection strategies are compared quantitatively by using the constraint between the information which an eavesdropper can obtain and the interference introduced. If the eavesdropper gets the full information, the detection rate of the original "Ping-pong" protocol is 50%; the detection rate of the second protocol which used two particles of EPR pair as detection particles is also 50%; and the detection rate of the presented protocol is 75%. In the end, the security of the proposed protocol is discussed. The analysis results show that the improved "Ping-pong" protocol in this paper is more secure than the other two. © Science China Press and Springer-Verlag Berlin Heidelberg 2011.


Li J.,Beijing University of Posts and Telecommunications | Song D.-J.,Beijing University of Posts and Telecommunications | Guo X.-J.,Beijing University of Posts and Telecommunications | Jing B.,Beijing University of Posts and Telecommunications | Jing B.,Beijing Institute of Applied Meteorology
Chinese Physics C | Year: 2012

In order to transmit secure messages, a quantum secure direct communication protocol based on a five-particle cluster state and classical XOR operation is presented. The five-particle cluster state is used to detect eavesdroppers, and the classical XOR operation serving as a one-time-pad is used to ensure the security of the protocol. In the security analysis, the entropy theory method is introduced, and three detection strategies are compared quantitatively by using the constraint between the information that the eavesdroppers can obtain and the interference introduced. If the eavesdroppers intend to obtain all the information, the detection rate of the original ping-pong protocol is 50%; the second protocol, using two particles of the Einstein-Podolsky-Rosen pair as detection particles, is also 50%; while the presented protocol is 89%. Finally, the security of the proposed protocol is discussed, and the analysis results indicate that the protocol in this paper is more secure than the other two. © 2012 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.


Dong S.-L.,Beijing Institute of Applied Meteorology
Shuikexue Jinzhan/Advances in Water Science | Year: 2012

This paper discusses the unreliability of extreme value statistical inference, its presentation, causes and ways of improving the reliability, practical methods and reliability evaluation. It advances the possibility of applying the phenomenon of super-fitting, sampling error, the domain of convergence criteria, the maximum likelihood estimation of refined estimates and rough estimates, the pan-likelihood estimation, multi-parent phenomenon, Monte Carlo stochastic simulation concepts or methods; and obtained reliable results of the extreme value statistical inference for the multiple meteorological elements of various weather station. The theory of small-sample statistics is initially formed.


Zhai Y.,Beijing Institute of Applied Meteorology | Zhao R.,Unit 61741 of PLA
Xitong Fangzhen Xuebao / Journal of System Simulation | Year: 2016

Linear moment is one of the important methods to estimate the extreme value distribution function in engineering practice. In order to improve the estimation performance for Gumbel distribution, the estimating results of twelve empirical distribution functions were simulated by using Monte Carlo method. The optimal linear moment estimation method was constructed based on the empirical distribution function with the minimum estimation error, and compared with ordinary moment, traditional linear moment and maximum likelihood method. The study shows that choosing an appropriate empirical distribution function can enhance the estimation accuracy. The optimal empirical distribution function varies depending on the sample size, and its result is quite satisfactory in most cases and offers the best among the other methods especially in the sample size of 1 000~10 000. © 2016, The Editorial Board of Journal of System Simulation. All right reserved.


Chen Y.-S.,Beijing Institute of Applied Meteorology
2010 International Conference on Machine Vision and Human-Machine Interface, MVHI 2010 | Year: 2010

To take account of both date flow and control flow in protocol consistency test, based on EFSM, this article puts forward that in data flow test, the method of the data dependence relation between variables is reused to generate test sequence, which improves path coverage rate; it also puts forward that in control flow test, the method of subsequence shortest covering-path is created to generate control flow test sequence, and the path stack algorithm is applied to merge test sequence to optimize test sets. © 2010 IEEE.


Yao Z.,Beijing Institute of Applied Meteorology | Li J.,University of Wisconsin - Madison | Zhao Z.,Beijing Institute of Applied Meteorology
Advances in Atmospheric Sciences | Year: 2015

It is nontrivial to extract the dust top height (DTH) accurately from passive instruments over land due to the complexity of the surface conditions. The Moderate Resolution Imaging Spectroradiometer (MODIS) deep blue (DB) algorithm can be used to infer the aerosol optical depth (AOD) over high-reflective surfaces. The Atmospheric Infrared Sounder (AIRS) can simultaneously obtain the DTH and optical depth information. This study focuses on the synergistic use of AIRS observations and MODIS DB results for improving the DTH by using a stable relationship between the AIRS infrared and MODIS DB AODs. A one-dimensional variational (1DVAR) algorithm is applied to extract the DTH from AIRS. Simulation experiments indicate that when the uncertainty of the dust optical depth decreases from 50% to 20%, the improvement of the DTH retrieval accuracy from AIRS reaches 200 m for most of the assumed dust conditions. For two cases over the Taklimakan Desert, the results are compared against Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) measurements. The results confirm that the MODIS DB product could help extract the DTH over land from AIRS. © 2015, Chinese National Committee for International Association of Meteorology and Atmospheric Sciences, Institute of Atmospheric Physics, Science Press and Springer-Verlag Berlin Heidelberg.


Zhao R.,Unit 61741 of PLA | Zhai Y.,Beijing Institute of Applied Meteorology
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2015

The generalized Pareto distribution (GPD) is a good probability distribution model to describe peak-over-threshold (POT) series, but the determination of its threshold is a great challenge in practical application. To solve this problem, we herein describe a Pickands bootstrap moment method for estimation of the GPD parameters. The method is used to estimate the shape parameter of GPD and the optimum number of POT and calculate the threshold, then the scale parameter is obtained with the moment estimation method. This new method is applied to the daily precipitation series of the Beijing meteorological station and its results are compared with those estimated by the linear moment estimation method using the same threshold. The comparison shows that it has a good ability of parameter estimation for GDP and generalized extreme value (GEV). From the fitting of the GDP quantiles and POT series, their correlation coefficients are up to 0.997 or more while their standard deviation and maximum deviation are the lowest. These results indicate that the Pickands bootstrap moment estimation method is obviously superior to the linear moment estimation. © All right reserved.


Guo G.,National University of Defense Technology | Guo G.,University of Rostock | Li K.,Beijing Institute of Applied Meteorology | Wang Y.,Hunan First Normal University
Physica A: Statistical Mechanics and its Applications | Year: 2014

We investigate the solutions of a modified fractional diffusion equation which has a secondary fractional time derivative acting on a diffusion operator. We obtain analytical solutions for the modified equation in the finite and semi-infinite domains subject to absorbing boundary conditions. Most of the results have been derived by using the Laplace transform, the Fourier Cosine transform, the Mellin transform and the properties of Fox H function. We show that the semi-infinite solution can be expressed using an infinite series of Fox H functions similar to the infinite case, while the finite solution requires double infinite series including both Fox H functions and trigonometric functions instead of one infinite series. The characteristic crossover between more and less anomalous behaviour as well as the effect of absorbing boundary conditions are clearly demonstrated according to the analytical solutions. © 2014 Elsevier B.V. All rights reserved.


Yao Z.,Beijing Institute of Applied Meteorology | Han Z.,Beijing Institute of Applied Meteorology | Zhao Z.,Beijing Institute of Applied Meteorology | Lin L.,Beijing Institute of Applied Meteorology | Fan X.,CAS Institute of Atmospheric Physics
Remote Sensing of Environment | Year: 2010

The purpose of this study is to investigate the possibility of identifying overlapping clouds that contain thin cirrus overlying a lower-level water cloud by synergetic use of POLDER-3 (Polarization and Directionality of the Earth Reflectance) and MODIS (MODerate resolution Imaging Spectroradiometer) data. When thin cirrus clouds overlap the liquid cloud layer, the liquid information may be obtained by POLDER observations and the presence of the cirrus may be inferred from the MODIS CO2-slicing technique. An initial comparison of the POLDER cloud phase and the MODIS cloud-top pressure for one scene over East Asia also shows that a large portion of clouds declared as liquid water clouds by POLDER-3 correspond to the lower cloud-top pressures derived from MODIS. As a result, an overlapped cloud identification method is proposed under the assumption that the multilayered cloud would be present if the POLDER cloud phase is liquid water and the MODIS cloud-top pressure is less than 500hPa. For the studied scene, the comparison of the multilayered cloud identification results with CloudSat and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) observations illustrates that the proposed method could detect multilayered clouds when the upper cirrus has a visible optical thickness of less than 2.0. Then the identification results are compared with the MODIS Cloud_Multi_Layer_Flag. It is indicated that the consistency between the multilayered clouds from the proposed synergy and MODIS-operational algorithm increases gradually from over 40% to nearly 100% with the increase of the confidence level of the MODIS multilayered clouds from the lowest to the highest. Further analysis suggests that the majority of multilayered clouds falsely classified as single-layered clouds by the proposed method may correspond to relatively thick cirrus covering lower-level water clouds. Additionally, an index by using the multilayered cloud detection differences from the two methods is proposed to provide some information on the optical thickness of the cirrus covering lower-level water cloud. Finally, quantitative comparisons are extended to four other scenes at different locations by using active measurements. The results also show that the mean visible optical thickness of the high-level clouds of the multilayered clouds detected by both methods (1.57) is remarkably less than that by only MODIS-operational method (2.84), which means that the differences between the results from the two methods are mainly caused by the different sensitivities to the visible optical thickness of the high-level cloud and could be used to indicate the range of the visible optical thickness of the cirrus clouds covering the lower-level water clouds. © 2010 Elsevier Inc.

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