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61.
We study the Tardos’ probabilistic fingerprinting scheme and show that its codeword length may be shortened by a factor of
approximately 4. We achieve this by retracing Tardos’ analysis of the scheme and extracting from it all constants that were
arbitrarily selected. We replace those constants with parameters and derive a set of inequalities that those parameters must
satisfy so that the desired security properties of the scheme still hold. Then we look for a solution of those inequalities
in which the parameter that governs the codeword length is minimal. A further reduction in the codeword length is achieved
by decoupling the error probability of falsely accusing innocent users from the error probability of missing all colluding
pirates. Finally, we simulate the Tardos scheme and show that, in practice, one may use codewords that are shorter than those
in the original Tardos scheme by a factor of at least 16.
相似文献
62.
《Helvetica chimica acta》2017,100(4)
[K(crypt‐222)]+ ( 1 ) and [K(crypt‐222)]+ ( 3 ) are isostructural, displaying nearly identical unit cell parameters. The two structures are similar to the extent that the previously reported [K(crypt‐222)]+ model can be refined against the new data for [K(crypt‐222)]+ , with extra electron density being observed from the fourth fluorine atom of the . In agreement with experimental observations, theoretical calculations suggest that deprotonated [K(crypt‐222)]+ is highly unstable even at as low as 195 K. The previously considered 1:1 CHF 3 clathrate of deprotonated [K(crypt‐222)]+ (crystallographically indistinguishable from 1 ) is ruled out on the basis of all available data. 相似文献
63.
Morteza Bararjanian Saeed Balalaie Frank Rominger Sanaz Barouti 《Helvetica chimica acta》2010,93(4):777-784
A three‐component reaction of benzaldehyde derivatives, methyl cyanoacetate, and guanidinium carbonate affords 2‐amino‐4‐aryl‐1,6‐dihydro‐6‐oxopyrimidine‐5‐carbonitriles and the four‐component reaction of benzaldehyde derivatives, methyl cyanoacetate, and guanidinium hydrochloride in the presence of piperidine leads to piperidinium salts of pyrimidinones. X‐ray crystallography data confirm self‐assembly and H‐bonding in these compounds. 相似文献
64.
Yang Yu Hao Gao Yi Dai Ying Wang He‐Ru Chen Xin‐Sheng Yao 《Helvetica chimica acta》2010,93(4):763-771
Eight new monoterpenoids, jasminoside J ( 1 ), jasminoside K ( 2 ), 6′‐O‐trans‐sinapoyljasminoside B ( 3 ), 6′‐O‐trans‐sinapoyljasminoside L ( 4 ), jasminosides M–P ( 5 – 8 ), together with three known analogues, jasminoside C ( 9 ), jasminol E ( 10 ), and sacranoside B ( 11 ), were isolated from the fruit of Gardenia jasminoides Ellis (Rubiaceae). Their structures were elucidated by spectral and chemical methods. 相似文献
65.
The thermal reactions of the 2,2,3‐trisubstituted N‐phthalimidoaziridine 1a with dimethyl acetylenedicarboxylate (DMAD), thioketones 4a – 4d , and dimethyl azodicarboxylate ( 5 ) proceed even at room temperature leading to the five‐membered cycloadducts 2a, 6 – 8 , and 12 , respectively, with retention of the spatial arrangement of the aziridine substituents, in contrast to the expectation based on the conservation of orbital symmetry in concerted reactions. The analogous reactions of the tetrasubstituted phthalimidoaziridine 1b with thioketones at 40° lead to the 1,3‐thiazolidine derivatives 10 and 11 as mixtures of diastereoisomers. These unexpected results may be explained by either the isomerization of the intermediate azomethine ylides or a non‐concerted stepwise cycloaddition reaction of these ylides with the dipolarophiles. The structures of some adducts have been determined by X‐ray crystallography. 相似文献
66.
The curved ray tracing method (CRT) is extended to radiative transfer in the linear-anisotropic scattering medium with graded index from non-scattering medium. In this paper, the CRT is presented to solve one-dimensional radiative transfer in the linear-anisotropic scattering gray medium with a linear refractive index and two black boundaries. The predicted temperature distributions and radiative heat flux at radiative equilibrium are determined by the proposed method, and numerical results are compared with the data in references. The results show that the CRT has a good accuracy for radiative transfer in the linear-anisotropic scattering medium with graded index and the dimensionless emissive power and dimensionless radiative heat flux depend on the dimensionless refractive index gradient. It can also be seen that the dimensionless refractive index gradient has important effects on the temperature discontinuity at the boundaries. 相似文献
67.
Jonathon E. Beves Edwin C. Constable Catherine E. Housecroft Markus Neuburger Silvia Schaffner Jennifer A. Zampese 《Helvetica chimica acta》2009,92(11):2214-2226
The syntheses of the five 2,2′: 6′,2″‐terpyridine (tpy) ligands 5 – 9 functionalized in the 4′‐position with a hydrazone substituent RR′C?N? NH (R=R′=Me; R=H, R′=4‐BrC6H4, 4‐O2NC6H4, 4‐MeOC6H4, or 3,5‐(MeO)2C6H3) are described. Protonation of the tpy domain of the ligands is facile. Solution behaviour has been studied by NMR and electronic spectroscopies. Representative structural data are presented for neutral and monoprotonated ligands, and illustrate that H‐bonding involving the formal amine NH unit is a dominant structural motif in all cases. 相似文献
68.
介绍了一种基于THGEM的X射线光斑寻迹探测器,用于X射线单光子计量技术研究和测量,探测器有效面积200 mm×200 mm,采用128路基于ASIC和FPGA的高速读出电子学,探测器分为中间高分辨区和外围低分辨区两部分,两部分共用一套读出电子学。实验在中国计量科学研究院利用X光机产生的束线,测试光斑位置、光斑精细分布以及探测器的位置分辨。实验结果表明,探测器实现了同时对光斑寻迹和光斑的精细测量,探测器中间高分辨区x方向的位置分辨率为0.63 mm(FWHM),y方向位置分辨率为0.62mm(FWHM),探测器各项性能指标均达到了预期目标。This paper introduces the detector of X-ray spot tracing based on the THGEM. It is used for X ray single photon measurement technology research and measurement with an effective area of 200 mm×200 mm. The circuit board has 128 array of high speed readout electronics based on ASIC and FPGA. And it is divided into two parts:the middle area of high sensitive and the peripheral area of low sensitive. The two parts share a set of readout electronics. The experiment tests the position and the fine structure of the beam line produced by X ray machine in National Institute of Metrology. The results of the experimental show that the detector realizes both the spot tracing and the fine structure of the spot. The position resolution is 0.63 mm in x direction and 0.62 mm in y direction in high sensitive of the detector, which achieve the desired goal of preliminary design. 相似文献
69.
70.