高可靠性移动通信网络数据库跨域安全检索研究

高可靠性移动通信网络数据库在跨域检索过程中容易被攻击者修改数据,导致数据检索精度与效率下降,因而研究高可靠性移动通信网络数据库跨域安全检索方法。通过主密钥对和用户私钥、公钥确定密文索引,结合密文获取安全查询索引,提取安全查询索引关键词。通过改进TF-IDF权值方法确定索引关键词相关度分数,结合相关度分数对检索结果进行排名和过滤,将检索结果返回给数据使用者,完成跨域安全检索。实验结果表明,这种方法的检索结果的查全率、查准率、效率均较高,检索效果好。

Study of the Firing Temperature of Marajoara Archaeological Ceramics by EPR Associated to INAA Data

The Marajó Island is the largest island of the Marajō archipelago, located in the north of Brazil. In this region, at the end of 19th century, it was identified an archaeological society named Marajora, which occupied the island from 400 to 1,350 AD. It was characterized by a ceramic style recognized by its beauty and exuberance. Until this moment, the physical and chemical analysis studies in this ceramics are scarce and this kind of studies may help archaeological studies performed in the island. With this purpose, this work presents a preliminary study of the firing temperature in the ceramics. For that, the elementary concentrations of 109 samples from Museu de Archaeology and Ethnology Museum of the University of Sáo Paulo and samples collected in the Marajá Island were studied. The samples were analyzed using instrumental neutron activation analysis in which the elemental concentration of Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sc, Sm, Ta, Tb, Th, U, Yb and Zn were determined. The interpretation of the results was made using multivariate statistical approaches and showed the existence of three chemical groups. Some samples of each cluster were chosen for the determination of their firing temperatures by electron paramagnetic resonance, in order to verify if different firing temperatures was associated with different elemental groups of ceramic samples. The results showed that there are no statistical differences in the firing temperature between the samples from Archaeology and Ethnology Museum and the contemporary samples of the Marajá Island.

IDFT Numerical Simulation Method for Gaussian Rough Surface with Relatively Large Correlation Length

A numerical simulation method based on inverse discrete Fourier transform(IDFT)is presented for generating Gaussian rough surface with a desired autocorrelation function(ACF). The probability density function of the height distribution of the generated Gaussian surface and the root-mean-square height of the rough surface are also considered. It is found that the height distribution of the generated surface follows the Gaussian distribution, the deviation of the root-mean-square height of the modeled rough surface from the desired value is smaller than that of Patir's method, and the autocorrelation function of the modeled surface is also in good agreement with the desired autocorrelation function. Compared with Patir's method, the modeled surface generated by the IDFT method is in better agreement with the desired autocorrelation function, especially when the correlation length is relatively large.

Gaining Satisfaction and Trust in a Brand Website

This study attempts to examine whether ＂trust＂ and ＂satisfaction＂ in a brand website are affected by the level of website interactivity as well as the four facets （aesthetics, playfulness, service excellence, and customer return on investment） of the Experiential Value. Three interactive versions （low, medium, and high） of a website for a fictitious laptop brand were designed. An online experiment was conducted 180 students participated in the study. Data analysis indicated that higher levels of trust and satisfaction were generated when participants were exposed to the low interactive version of the website. Regarding the four facets of Experiential Value, aesthetics and customer return on investment （croi） have positive relationship with both trust and satisfaction in the brand website. Playfulness appears to have negative whereas excellence does not have significant relationship with trust and satisfaction. Limitations and guidelines for future research are provided.

New Metrics from a Fractional Gravitational Field

Agop et al. proved in Commun. Theor. Phys. （2008） that, a Reissner-Nordstrom type metric is obtained, if gauge gravitational field in a fractal spacetime is constructed by means of concepts of scale relativity. We prove in this short communication that similar result is obtained if gravity in D-spacetime dimensions is fractionalized by means of the Glaeske-Kilbaz Saigo fractional. Besides, non-singular gravitational fields are obtained without using extra-dimensions. We present few examples to show that these gravitational fields hold a number of motivating features in spacetime physics.

Optical trapping of metallic Rayleigh particle by combined beam

Radiation forces and trapping stability of metallic （i.e. gold） Rayleigh particle by combined beam are analyzed, and the combined beam is formed by superimposing two partially coherent off-axis fiat-topped beams. The dependences of radiation forces on off-axis distance parameter, correlation length and particle radius are illustrated by numerical examples. The results show that there exist critical values d0,c and or σ0,c for the combined beam. For 0〈d ≤ d0,c or 0〈σ0 ≤ σ0,c the Gaussianlike intensity profile takes place at the geometrical focal plane, so that the transverse gradient force can act as restoring force. As the off-axis distance parameter increases or the correlation length decreases, the maximal intensity, the radiation force and trapping stiffness become smaller, while the transverse and longitudinal trapping ranges become larger. In comparison with a single beam, the combined beam is more favourable for trapping metallic Rayleigh particle owing to the stronger trapping stiffness and the larger trapping range.