Digital fingerprinting is a novel way for copyright protection of digital contents. A survey of digital fingerprinting is presented in this paper. First, the research background of digital fingerprinting is introduced, then the common model and basic requirements of fingerprinting schemes are summarized. Second, a brief overview of the encoding and tracing of digital fingerprinting is given, with some details on two typical fingerprint coding methods. Third, considering the evolution of digital fingerprinting protocols, the ideas of asymmetric and anonymous fingerprinting are introduced and the fundamental problems are analyzed. Moreover, some directions worth noting are pointed out.
branch data,this paper gives a sufficient and necessary condition of them to be realized as the branch data of some branched coverings over the Riemann sphere.
One improved Hill estimator using GLS(general least squares) is introduced, which overcomes some defects of Hill estimator, and is used to evaluate VaR. The VaR of index of Shanghai Composite, Hang seng, Dow Jones, Nasdaq, Nikkei are estimated and compared, and a simple analysis of the result is given.
Parameters of the diffusion about yield rate of Shanghai Index are obtained by using the MCMC method. Then, the distribution of future yield of next day is given by Monte Carlo, and the validity of the distribution is checked.At last, some risk analysis is made.
This study simulates the effects of different temperature pulse inlet conditions on non Fourier heat conduction problem, and numerically predicts different non Fourier heat conduction characters produced by different pulse types and different pulse frequencies, respectively. Also, the differences between thermal wave, non Fourier and Fourier heat conduction under the same pulse condition are showed.
This paper presents a dynamic propagation view that the continuity wave and dynamic wave acting on each other results in the non linear solution under certain flow conditions. Based on the drift flux model and empiric formula, hyperbolic equation of one dimensional gas liquid two phase flow is deduced, wave theory approach is performed in detail by using characteristic curve method. The numerical analysis shows flow pattern transition location propagates downstream ward for lower void fraction while it moves upstream ward for higher void fraction. Flow pattern transition would not occur for very high void fraction. The calculations show that the inception of flow pattern transition is at the void fraction of 0.27 and the flow pattern transition stops at the void fraction of 0.58, which is in good agreement with experimental results in literatures.
To meet the requirements of the BEPCII linac upgrade, the studies on beam orbit correction are carried out. The reasons of the orbit offset and the orbit correction methods are studied. By means of least square method, the satisfying simulation results of beam orbit correction are obtained.
In high throughput screening process, mathematic models are regarded as the foundations for large scale screening for compound library and automating the process. With thermodynamics and kinetics as the means, the article provides synthetically dynamic models by analyzing the principle of screening. Meanwhile, the article also analyzes three probable interactions between drugs and targets, and deduces corresponding mathematic models.
Anionic Gemini surfactant, N, N′ Dipalmitoyl ethylenediamine diacetic Acid, sodium salt, is synthesized and characterized by elemental analysis and 1HNMR. The critical micelle concentration (cmc) has been determined by means of surface tension measurements. Wettability of the surfactant aqueous solution on silica gel is far better than that of dodecylbenzenesulfonic acid, sodium salt.
After isolation and purification of four steps, specific activity of UGPase from Apocynaceae cell is 204 9 U/mg. Compared with crude cell culture, specific activity is 97 times, and recovery yield is 21%. UGPase can be used in the synthesis of UDPG, and it has higher stability. The best available pH of UGPase is about 7 2, the best available temperature about 37℃. Mg2+ is necessary for UGPase to use. The high concentration of UTP and Glc 6 P can inhibit the activity of UGPase.
On the basis of the helix theory proposed by the authors,the relationship between sructure and rotatory direction is analyzed for the tartaric acid and glyceraldehyde.The results show that there is a close correlation between structure and optical activity in both compounds even if they can form many hydrogen bonds.
The analysis of cross selling is one of the important parts in analytical CRM. We present a constraint based association rules mining algorithm AApriori with the specified antecedent and the constrained consequent. The outcome of this algorithm can help enterprises use selling products to popularize products that are unpopular. At the same time, an algorithm CApriori that the consequent is specified and the antecedent is constraind is presented. It can effectively support enterprises to exploit the market of new products. The evaluation demonstrated that the algorithm AApriori and CApriori could quickly get exact information that the enterprise wants.
The NCC T63L20 model of the National Climate Center, China Meteorological Administration is employed to simulate the summer (June-August) flood during the characteristic years. This model utilizes Kuo type parameterized scheme and Gregory parameterized scheme respectively. The simulations show that the Gregory parameterized scheme, which is still used in the United Kingdom Meteorological Office routine model, simulates more reasonable rainfall area amount and distribution compared to the Kuo type scheme. Moreover, the Gregory scheme better simulates the rainfall amount than the Kuo type scheme. On the whole, the Gregory scheme provides a good simulation of the main features of the seasonal precipitation and general circulation in China, although the simulated result still exhibits some departures from the observations and the scheme needs to be improved further.
Changes of 13 trace elements’ contents in wetland and tillage soils, in the drainage basins of Naoli River, Bielahong River and Nongjiang River in the hinterland of Sanjiang Plain, are studied. The results show that contents of B, Cd, Cu, Ni, Zn in tillage soils are lower than those in natural wetlands, while contents of Ba, Be, Co, Cr, Mn, Pb, Sr, Ti are higher. The vertical stratification of trace elements in natural wetland soils is significant while in tillage soils section changes of elements, except Pb, are gentler than those in natural wetland soils. Some elements in wetland and tillage soils have a similar trend excluding B and Cd. In addition, the correlations between some elements in tillage soils are not so significant as those in natural wetland soils.
Based on the model checking theory, we derive the running mode analysis method of three party cryptographic protocols from the running mode analysis method of two party cryptographic protocols. To test this method, we use it to analyze the Davis Swick protocol and successfully prove the security of protocol. Therefore, we can draw a conclusion that running mode analysis of three party cryptographic protocol is available.
Systematic investigations were carried out into the sources of heavy metal pollution in phaiozem throughout twenty two counties/cities in northeast China. Heavy metals of Cd, Pb, Cu, Zn in the soil samples were measured by atomic absorption spectrophotometry, and they ranged from 0 013-2 31 mg/kg,10 52-57 48 mg/kg, 42 13-227 10 mg/kg and 9 95-46 18 mg/kg respectively. According to the evaluation of single contaminative index and the comparing of topsoil and subsoil, it was found that 42 9 percent of the samples was polluted by Cd, and most of the pollutants were assembled in middle and serious levels. The polluted situation of Pb, Zn and Cu was not reflected accurately by the evaluation of single contaminative index. It was showed that there is great difference between the two methods of evaluation. The contaminative phenomenon was very obvious by the evaluation of comparing topsoil and subsoil. 57 1%, 21 0%,53 3% of topsoil samples, respectively, were polluted by Pb, Cu and Zn. Most of the polluted samples were distributed in the fields in suburbs and in the areas near the industrial parts of cities.
Recently the dye sensitized solar cell (DSSC) is under the intensive investigation because it is highly efficient and provides an environmentally and economically credible alternative concept to conventional photovoltaic devices. This paper examines the possibility of using nanocrystalline ZnO as an electrode to make dye sensitized solar cells, which is prepared by sol gel techniques. The performance of this cell is also discussed and compared with dye sensitized solar cells based on nanocrystalline TiO 2.
In this paper, we present a threshold signature scheme with fault tolerance,which has improved the existing schemes. In this scheme, the messages can be signed even if there are some malicious participants.
For the non conservative schemes of nonlinear evolution equations, taking two dimensional shallow water wave equation as an example, the necessary conditions of computational stability are given. Based on the numerical tests, the relationship between the nonlinear computational stability, the construction of difference schemes, and the form of initial values is further discussed. It is proved through theoretical analysis and numerical tests that the computational stability of non conservative schemes is not only dependent on the structure of the scheme, but also on the form of initial values and their partial derivatives.
Based on the terrestrial heat flow and crustal structure data, this paper calculates the temperature and the thermal structure of lithosphere in the South China Sea. The result shows that there is a larger change of temperature along vertical direction in the central basin, which is caused by the uplifting of mantle. Mantle uplifting in local areas would cause seabed outspread in multi periods and multi aspects.As a result, different areas of heat flow value in the central basin are formed. The percentage of heat flow from mantle is bigger than 80% in terrestrial heat flow, whereas the percentage of lower crustal heat flow is smaller than 20% in terrestrial heat flow. We argue that two factors might produce the thinning of layer 3 in central basin crust. One factor is the lower original crustal temperature, the other is the slowly cooling process after late heating event.
Thioether, selenide and phosphino derivatives of ferrocenyl oxazolines, synthesized from ferrocenyl oxazolines, were found to be effective in palladium catalyzed allylic alkylation with up to 99% ee. With P, N ligand, palladium catalyzed allylic amination was achieved with 97% ee. The enantio control was dominated by the central chirality. However, the match between planar chirality and central chirality is critical for high enantioselectivity. A series of planar chiral ferrocene modified bisphosphine pocket ligands were synthesized and found to be very effective in construction of quaternary carbon centers using asymmetric allylic alkylation. Some non coded alpha, alpha disubstituted amino acids were obtained with up to 75% ee using ketone imino esters. Using enolate of simple ketone as nucleophile, alpha, alpha disubstituted ketones were obtained with up to 95% ee. A new type of ferrocene based P, N ligands has been synthesized and was found to be very effective in regio and enantio selective palladium catalyzed allylic alkylation and amination of mono substituted allylic acetates. The free OH in the ligand was very important for selective control by the hydrogen bonding with benzylamine in later reaction, which was proved by experimental results.
Interferon (IFN) system is the first line of defense against virus invasion in vertebrate. So far relative little was known concerning IFN system genes other than in mammals. In fish, nearly 40 year evidence available for existence of IFN system mainly lies in the observation that fish and fish cells are much earlier known to produce molecules with IFN like activity as measured by a cell protection test, and that IFN inducible gene, Mx homologue, has been identified in a limited number of fish species in the latest years. Previously we reported that UV inactivated GCHV was able to induce high level of IFN like molecule for establishment of antiviral state in cyprinid fish cell lines, such as crucian carp (Carassius auratus L.) blastulae embryonic (CAB) cells. In the current study, in order to better understand innate immune mechanisms of fish cells responsive to virus infection, an ideal cell model system for identifying fish antiviral relevant genes was firstly established, and on the basis of induction and characterization of CAB IFN, a subtractive cDNA library accumulating an enhanced mRNA level of fish antiviral relevant genes was also constructed. Secondly, a subset of fish IFN system genes and some unidentified ESTs that were found no similarity by BLASTX were retrieved by screening of the library, and expression analysis demonstrated that they were IFN stimulated genes (ISGs) as well. Thirdly, according to the latest research of mammals, 19 full length cDNAs of fish IFN system genes were cloned, including crucian carp IFN, IFN signal transduction factor STAT1, IFN regulatory factor IRF7, putative IFN antiviral effectors Mx1, Mx2, PKR, Viperin, IFI56, and some ISGs with function unknown, including IFI58, ISG15 1, ISG15 2, Gig1, Gig2 and so on. Finally, further studies on the characterization of structure, expression, induction and evolution of some important relevant genes reveal that several mechanisms in fish innate immune following virus infection, including signal recognition, signal transduction and regulation, antiviral pathways, were similar to those in mammals.
Soil organic matter content is the most important property to affect CH 4 production. There is no specific soil property to affect significantly CH4 oxidation. The CH4 production, oxidation and emission potentials are all stimulated by higher soil water content during the previous non rice growing season. Soil water history might be a more important factor than soil property in controlling the spatial variability of CH4 emissions from rice fields on large spatial scale. The results demonstrate the importance of water management between rice crops as a means to regulate CH4 production,oxidation and emission during rice growing season.