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911.
Predicting the scale of information diffusion is an important task for many social network services (SNS) operators and enterprises. In this paper, the authors investigate the effects of two types of indicators, user attributes and social network attributes, and study on the accuracy of predicting the scale of information diffusion, and how to select an appropriate model that can fit real data better and have a higher accuracy. The experimental results show that both user attributes and social network structure attributes have significant effects on the scale of information diffusion. At the same time, three data mining models are constructed in this paper to predict the scale of information diffusion and compare their prediction accuracy. It is found that neural network model performs much better than decision tree and linear regression do.  相似文献   
912.
韦余红 《通信技术》2009,42(2):270-271
研究了无线POS机具的安全策略、GPRS的安全机制、防火墙的应用及银行前置的安全认证和数据加密的应用管理等内容。  相似文献   
913.
MathIOmica‐MSViewer is an add‐on graphical user interface utility for the Mathematica software system which facilitates the visualization and exploration of spectra from open format mass spectrometry files (mzXML and mzML standard community formats). The viewer was designed for simplicity and handling of large mass spectrometry data files. To facilitate searches, users may use search filters for the spectra based on mass to charge ratios and retention times, and visualize precursor spectra associated to a parent spectrum. Availability: The viewer is available as a Mathematica notebook (MathIOmica‐MSViewer.nb) at https://doi.org/10.5281/zenodo.321385 . The software is provided under an MIT License. © 2017 The Authors. Journal of Mass Spectrometry published by John Wiley & Sons, Ltd.  相似文献   
914.
拉曼光谱是一种分子散射光谱,利用物质的特征拉曼光谱,可实现对其结构、成分、浓度等的检测.多组分物质拉曼光谱的定量分析是一个有待深入研究的课题.采用遗传算法程序对10组分的混合矿石样品的拟合拉曼光谱数据进行了分析,对同一条件下算法多次计算的结果和不同条件下算法的表现进行了讨论,分析了算法设计和基本参数的不同对算法收敛速度以及对计算结果的精确性和稳定性的影响,验证了遗传算法用于多组分样品拉曼光谱数据分析的可行性、有效性和精确性.  相似文献   
915.
大气激光通信链路的性能仿真   总被引:1,自引:3,他引:1  
大气衰减和大气湍流严重影响着大气激光通信的链路质量。建立了大气信道的激光通信链路模型,研究了衰减信道和湍流信道中光链路的传输影响,对最大通信速率、链路功率余量和误码率进行了分析和计算。结果表明,大气湍流严重影响系统误码率,当大气闪烁指数斫是0.07时,可达到的最小误码率为10^-9。分析结果可为系统设计提供参考依据。  相似文献   
916.
粗糙集理论是处理不确定性问题的数学方法,本文提出了基于粗糙集与小波变换相结合的图像融合算法。该方法首先将粗糙集理论应用于图像滤波中,对含有椒盐噪声的图像进行粗糙中值滤波,然后对滤波后的图像进行小波融合。实验结果表明,粗糙中值滤波有较强的去噪能力,且较好地保持了图像的细节信息,在此基础上进行小波融合,使得融合结果图像具有良好的效果。  相似文献   
917.
Nine low-lying electronic states of the AsP molecule, including Σ , Ⅱ, and △ symmetries with singlet, triplet, and quintet spin multiplicities, are studied using multi-reference configuration interaction method.The potential energy curves and the spectroscopic constants of these nine states are determined, and compared with the experimental observed data as well as other theoretical works available at present.Three quintet states are reported for the first time.Furthermore, the analytical potential energy functions of these states are fitted using Murrell-Sorbie function and least square fitting method.  相似文献   
918.
Two vertical-cavity surface-emitting lasers(VCSELs) are mutually coupled through a partially transparent mirror (PTM) placed in the pathway. The PTM plays the role of external mirror,which controls the feedback strength and coupling strength.We numerically simulate this system by establishing a visible SIMULINK model.The results demonstrate that the anticipation synchronization is achieved and it can tolerate some extent frequency detuning.Moreover,the system shows similar chaos-pass filtering effect on unidirectionally coupled system even both VCSELs are modulated.This system allows simultaneously bidirectional secure message transmission on public channels.  相似文献   
919.
Based on the neutron induced fission fragment mass distribution data up to neutron energy 20 MeV measured with the double kinetic energy method (KEM) and the radio active method (RAM), the systematics of fission fragment mass distribution was investigated by using 5 Gaussian model and the systematics parameters were obtained by fitting the experimental data. With the systematics, the yields of any mass A and at any energy in the region from 0 to 20 MeV of neutron energy can be calculated. The calculated results could well reproduce the experimental data measured with KEM, but show some systematical deviation from the data measured by RAM, which reflects some systematical deviations between the two kinds of measured data.The error of systematics yield was calculated in an exact error transformation way, including from the error of the experimental yield data to the error of the discrete parameters, then to the systematics parameters,and at last to the yield calculated with systematics.  相似文献   
920.
The surface energy of MgO is determined using experimental data collected from equilibrated thermal grooves circumscribing island grains. Local equilibrium assumptions at each groove require that the Herring equations be satisfied at each data site, thereby yielding a large and overdetermined system of equations involving the surface energy . This inverse problem is then solved using a new technique that is statistical in nature and multiscale in implementation. The resulting discrete solution represents a statistically significant representation of the surface energy of MgO as a function of surface orientation. Comparisons to results derived from a more traditional approach, along with suggested further applications, are discussed.  相似文献   
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