视频版权自动认证系统的思考与设计

希望设计一套自动化,智能化,高效率的视频版权认证系统,系统总体采用了五层结构,设计了帧内数据的采样方法和由帧内采样数据构成的采样值数组,对该采样值数组进行哈希变换,求得了基本特征值,将得到的值组织成了四树权帧顺序寻址多层哈希树,将该哈希树与其他数据一起组织成了数据区块,本区块包含着前一数据区块的加密哈希值和当前时间戳,计算本数据区块的哈希值,将其加密存储在本区块的最后的数据位置,形成了数据区块链,对封面、封底区块进行加密,对整个数据打包,形成视频节目自动版权证书,论述了容错机制.     

Minimum spanning tree–based delay‐aware mobile sink traversal in wireless sensor networks

Energy efficient data collection in a delay‐bound application is a challenging issue for mobile sink–based wireless sensor networks. Many researchers have proposed the concept of rendezvous points (RPs) to design the path for the mobile sink. Rendezvous points are the locations in the network where the mobile sink halts and collects data from the nearby sensor nodes. However, the selection of RPs for the design of path has a significant impact on timely data collection from the network. In this paper, we propose an efficient algorithm for selection of the RPs for efficient design of mobile sink trajectory in delay‐bound applications of wireless sensor networks. The algorithm is based on a virtual path and minimum spanning tree and shown to maximize network lifetime. We perform extensive simulations on the proposed algorithm and compare results with the existing algorithms to demonstrate the efficiency of the proposed algorithm of various performance metrics.     

He-LiH体系转动非弹性碰撞的理论研究

在单双迭代耦合簇CCSD(T)势能面的基础上,运用密耦方法讨论了He-LiH体系的转动非弹性碰撞.计算结果表明,对LiH分子j=0→j′跃迁,跃迁截面主要由各向异性的短程相互作用和长程的“软”排斥共同作用的结果,未见明显的长程吸引势贡献.态－态跃迁总截面表现出振荡结构,长程“软”排斥分波只对j=0向j′=1、2、3的跃迁总截面有较大贡献,而j′≥ 4跃迁的积分截面则几乎由各向异性的短程部分贡献.     

Diatomic potential well depths from analyses of high-resolution electron energy spectra for autoionizing collision complexes

High-resolution energy spectra of electrons released in Penning ionization collisions of metastable rare gas atoms Rg*(ns) (Rg = He, Ne, Ar, Kr, Xe) with several open-shell and closed-shell atoms are analyzed to determine the well depth of the potential energy curve which describes the respective autoionizing collision complex. We thereby elucidate trends in the chemical interaction of Rg* with closed-shell target atoms A(ns ²) and establish a basis for detailed comparison with the respective interactions involving open-shell, ground state alkali atoms A(ns). From electron energy spectra due to␣associative ionization (RgH⁺ formation) in Rg* + H(1s) collisions, we determine binding energies for the RgH⁺(¹Σ) ground state potential (Rg = Ne, Ar, Kr, Xe) with uncertainties around 0.03 eV. Received: 30 June 1998 / Accepted: 5 August 1998 / Published online: 28 October 1998     

Liquid chromatography/tandem mass spectrometric method for the simultaneous determination of tobacco-specific nitrosamine NNK and its five metabolites

A sensitive and robust high-performance liquid chromatography-electrospray ionization tandem mass spectrometry method to analyze 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and its five metabolites in one passage was developed and validated. The method achieved excellent reproducibility and accuracy. Linearity was observed for all six compounds (R² = 0.999) with detection limits (S/N ≥ 3) ranging from 0.2 to 2.4 pg on column and 0.01-0.12 ng ml⁻¹ in samples injected. Average intra-day and inter-day variations (% R.S.D.) were 1.2 and 3.5%, respectively. A sample preparation method involving C8 and C18 solid phase extraction provided satisfactory recovery of the analytes in mouse urine. Each NNK metabolite was identified by its chromatographic retention time and specific fragmentation pattern. Since the carcinogenicity of NNK is related to its metabolism, the method described in this report should facilitate toxicological investigations into the carcinogenesis due to NNK exposure in the environment.     

Capillary gas chromatography of plant tissues and soil phenolic acids

Summary A method for the separation of phenolic acids along with shikimic and quinic acids by means of capillary gas chromatography is described and discussed. The method involves the previous derivatization of the acids to trimethylsilyl derivatives and it has been applied to the separation of acids extracted from olive leaves and roots, elm leaves and a soil A horizon. Quite good results were achieved both from qualitative and quantitative points of view. Qualitative differences have been pointed out in the phenolic acid composition of two olive cultivars and between leaves and roots of the same cultivar; also two elm species can be discriminated on the basis of the phenolic acid content.     

Interacting walkers on the Cayley tree,and polymer statistics

We obtain the generating function for an ensemble of random walkers on the Cayley tree of coordination numberz. The pair interaction between walkers is taken into account. This forbids two walkers to occupy the same lattice point after an equal number of steps. Interacting polymer statistics results from this model if one associates time (or the number of steps) with an additional space coordinate. The limiting free energy appears in a form that corresponds to the phase transition of 3/2 order.     

双原分子—固体表面碰撞动态学的准经典轨迹法

本文用经典轨迹法结合MonTe-Carlo法及某些因素的量子化处理,提供考虑分子各种因素的双原子分子—固体表面碰撞动态学的综合研究方法。应用在H_2-Ni(100)面及H_2-W(100)面两体系时,得到与实验相符的结果。     

Quantitative HPTLC separation of flavonoid glycosides in the taxonomy of elm (Ulmus spp.)

Summary The flavonoid glycosides of elm (Ulmus spp.) leaves have been separated by means of HPTLC on silica gel and quantitative analysis carried out by densitometry. The results obtained were used for discriminant analysis in order to investigate whether the flavonoid pattern could be used for the classification of elms. The results readily showed the different provenance of four species and the attribution of an unknown sample to a species can be carried out. This result is important as it offers a chemical tool in the taxonomy of the elm. The classification method is compared with one based on qualitative data from two-dimensional chromatography of the flavonoid aglycones. It was found to exhibit much better results than those obtained from the cluster analysis of these qualitative data.     

On mean field equations for spin glasses

In this paper we study rigorously the random Ising model on a Cayley tree in the limit of infinite coordination numberz 8. An iterative scheme is developed relating mean magnetizations and mean square magnetizations of successive shells far removed from the surface of the lattice. In this way we obtain local properties of the model in the (thermodynamic) limit of an infinite number of shells. When the coupling constants are independent Gaussian random variables the SK expressions emerge as stable fixed points of our scheme and provide a valid local mean-field theory of spin glasses in which negative local entropy (at low temperatures) while perfectly possible mathematically may still perhaps be physically undesirable. Finally we examine the TAP equations and show that if the average over bond disorder and the limitz 8 are actually performed, one recovers our iterative scheme and hence the SK equations also in the thermodynamic limit.On leave from Mathematics Department, University of Melbourne, Parkville, Victoria 3052, Australia.