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161.
In this paper we study the difference between the 2-adic valuations of the cardinalities \( \# E( \mathbb {F}_{q^k} ) \) and \( \# E( \mathbb {F}_q ) \) of an elliptic curve E over \( \mathbb {F}_q \). We also deduce information about the structure of the 2-Sylow subgroup \( E[ 2^\infty ]( \mathbb {F}_{q^k} ) \) from the exponents of \( E[ 2^\infty ]( \mathbb {F}_q ) \). 相似文献
162.
José Andrés Armario Iván Bailera Joaquim Borges Josep Rifà 《Mathematics in Computer Science》2018,12(4):419-428
In this paper, we give a characterization of quasi-Hadamard groups in terms of propelinear codes. We define a new class of codes that we call quasi-Hadamard full propelinear codes. Some structural properties of these codes are studied and examples are provided. 相似文献
163.
With the progress in the information and communication fields, new opportunities and technologies for statistical analysis, knowledge discovery, data mining, and many other research areas have emerged, together with new challenges for privacy and data protection. Nowadays several personal records are kept in computerized databases. Personal data is collected and kept in census databases, medical databases, employee databases, among others. There has always been an asymmetry between the benefits of computerized databases and the rights of individual data subjects. Some data protection principles can be derived from the legal framework. In this survey, we present some basic cryptographic and non-cryptographic techniques that may be used for enhancing privacy, we focus mainly on anonymization in databases and networks, discuss some differences and interactions among the well-known models of k-anonymity and differential privacy and finally present some challenges to privacy that come from big data analytics. 相似文献
164.
We consider static spherically symmetric Lovelock black holes and generalize the dimensionally continued black holes in such a way that they asymptotically for large $r$ go over to the d-dimensional Schwarzschild black hole in dS/AdS spacetime. This means that the master algebraic polynomial is not degenerate but instead its derivative is degenerate. This family of solutions contains an interesting class of pure Lovelock black holes which are the $N$ th order Lovelock $\Lambda $ -vacuum solutions having the remarkable property that their thermodynamical parameters have the universal character in terms of the event horizon radius. This is in fact a characterizing property of pure Lovelock theories. We also demonstrate the universality of the asymptotic Einstein limit for the Lovelock black holes in general. 相似文献
165.
Josep Àlvarez Montaner 《代数通讯》2013,41(9):3695-3704
We prove that sequentially Cohen–Macaulay rings in positive characteristic, as well as sequentially Cohen–Macaulay Stanley–Reisner rings in any characteristic, have trivial Lyubeznik table. Some other configurations of Lyubeznik tables are also provided depending on the deficiency modules of the ring. 相似文献
166.
Marleen Morbee Antoni Roca Josep Prades-Nebot Aleksandra Pižurica Wilfried Philips 《Signal, Image and Video Processing》2008,2(2):129-140
In some video coding applications, it is desirable to reduce the complexity of the video encoder at the expense of a more
complex decoder. Wyner–Ziv (WZ) video coding is a new paradigm that aims to achieve this. To allocate a proper number of bits
to each frame, most WZ video coding algorithms use a feedback channel, which allows the decoder to request additional bits
when needed. However, due to these multiple bit requests, the complexity and the latency of WZ video decoders increase massively.
To overcome these problems, in this paper we propose a rate allocation (RA) algorithm for pixel-domain WZ video coders. This
algorithm estimates at the encoder the number of bits needed for the decoding of every frame while still keeping the encoder
complexity low. Experimental results show that, by using our RA algorithm, the number of bit requests over the feedback channel—and
hence, the decoder complexity and the latency—are significantly reduced. Meanwhile, a very near-to-optimal rate-distortion
performance is maintained.
This work has been partially supported by the Spanish Ministry of Education and Science and the European Commission (FEDER)
under grant TEC2005-07751-C02-01.
A. Pižurica is a postdoctoral research fellow of FWO, Flanders. 相似文献
167.
Sergi Jansana Guilhem Coussanes Jordi Puig Faiza Diaba Josep Bonjoch 《Helvetica chimica acta》2019,102(10)
A general procedure is reported for the synthesis of cis ring fused azapolycyclic compounds bearing an all‐carbon quaternary stereocenter at the ring fusion and an adequate functionalization for the assembly of new rings leading to advanced synthetic intermediates for Daphniphyllum alkaloid synthesis. The key carbon?carbon bond‐forming step in this approach is a radical cyclization of an N‐cycloalkenyl trichloroacetamide derivative involving a tetrasubstituted enamide to achieve polyfunctionalized lactams. 相似文献
168.
Guillermo Quiones‐Reyes Consuelo Agull Josep V. Mercader Antonio Abad‐Somovilla Antonio Abad‐Fuentes 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(27):9232-9237
Early warning systems for monitoring toxic events may benefit from the availability of monoclonal antibodies enabling the sensitive and specific detection of anatoxin‐a, a cyanotoxin involved in numerous cases of animal poisoning resulting from toxic algal blooms in freshwaters. Through the synthesis of three functionalized derivatives of anatoxin‐a, we have succeeded in generating the first‐ever reported immunoreagents (bioconjugates and antibodies) suitable for the development of immunoanalytical approaches aimed at rapid and onsite detection of this harmful cyanotoxin. 相似文献
169.
Diego Mateo Andrea Santiago‐Portillo Josep Albero Sergio Navaln Mercedes Alvaro Hermenegildo García 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(49):18007-18012
Prolonged (weeks) UV/Vis irradiation under Ar of UiO‐66(Zr), UiO66 Zr‐NO2, MIL101 Fe, MIL125 Ti‐NH2, MIL101 Cr and MIL101 Cr(Pt) shows that these MOFs undergo photodecarboxylation of benzenedicarboxylate (BDC) linker in a significant percentage depending on the structure and composition of the material. Routine characterization techniques such as XRD, UV/Vis spectroscopy and TGA fail to detect changes in the material, although porosity and surface area change upon irradiation of powders. In contrast to BCD‐containing MOFs, zeolitic imidazolate ZIF‐8 does not evolve CO2 or any other gas upon irradiation. 相似文献
170.
Ahmed Bazil Taha Carreras Darío Castro Marin Eduardo Garcia 《Wireless Personal Communications》2021,117(4):2757-2780
Wireless Personal Communications - Semantic Web content extracting are the augmentation of the present web where the data is given in the better importance and allowing users to work close by close... 相似文献