How to distinguish between a block cipher and a random permutation by lowering the input entropy

IEEE 35th International Carnahan Conference on Security Technology. Londres, 16-19 October 2001A novel cryptanalysis technique is presented, and its suitability for distinguishing a block cipher algorithm or a hash function from a random permutation is explained. Additionally, we propose a genetic algorithm based implementation and show some preliminary results of these ideas on reduced rounds versions of the block cipher TEA

Emociones de profesores de matemáticas: un estudio exploratorio

En matemática educativa más allá de la amplia investigación sobre ansiedad matemática de profesores en pre-servicio y en servicio muy poco se sabe de las emociones discretas de los profesores de matemáticas en pre-servicio y en servicio. Para empezar a llenar este hueco el presente estudio exploratorio tiene el objetivo de identificar las emociones de maestros. Para la toma de los datos aplicamos un cuestionario a 13 profesores de preparatoria en servicio. Los resultados muestran que las emociones de cada uno de los profesores son desencadenadas por su valoración de las situaciones en función, principalmente, de la deseabilidad de la meta de persecución activa ‘que los estudiantes aprendan’ y por las metas de interés subordinadas de ‘que los estudiantes se interesen en la clase’ y ‘que los estudiantes participen en la clase’

Genetic architecture of tolerance to acrolein in Drosophila melanogaster

International audienc

DMRG study of the Bond Alternating \textbf{S}=1/2 Heisenberg ladder with Ferro-Antiferromagnetic couplings

We obtain the phase diagram in the parameter space $(J'/J, \gamma)$ and an accurate estimate of the critical line separating the different phases. We show several measuments of the magnetization, dimerization, nearest neighbours correlation, and density of energy in the different zones of the phase diagram, as well as a measurement of the string order parameter proposed as the non vanishing phase order parameter characterizing Haldane phases. All these results will be compared in the limit $J'/J\gg 1$ with the behaviour of the $\textbf{S}=1$ Bond Alternated Heisenberg Chain (BAHC). The analysis of our data supports the existence of a dimer phase separated by a critical line from a Haldane one, which has exactly the same nature as the Haldane phase in the $\textbf{S}=1$ BAHC.Comment: Version 4. 8 pages, 15 figures (12 figures in document

Conceptual design of the EU-DEMO dual coolant lithium lead equatorial module

© 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Within the framework of EUROfusion Program, the Dual Coolant Lithium Lead (DCLL) is one of the four EU breeder blanket concepts that are being investigated as candidates for DEMO. DCLL uses PbLi as the main coolant, tritium breeder, tritium carrier, and neutron multiplier. The main structures, including the first wall, are cooled with helium. The EU program proposed for the next years will consider a DCLL version limited to 550 °C in order to allow the use of conventional materials and technologies. During the first year of EUROfusion activities, a draft design of the DCLL has been proposed. The main blanket performances were adapted to the new specifications and the CAD model of DEMO. The breeder zone has been toroidally divided into four parallel PbLi circuits, separated through stiffening grid radial walls. The PbLi flow routing has been designed to maximize the amount of thermal power extracted by flowing PbLi and to avoid the occurrence of reverse flows due to volumetric heating. Thermal hydraulics, magnetohydrodynamic and neutronics calculations have been performed for the first draft design. The new DCLL design employs Eurofer-alumina-Eurofer sandwich as flow channel insert (FCI).Postprint (published version

Teorethical studies of the stability of 8a-alkyll-1,2,3,4,6,8a- hexahydronaphtalen-1-ones using semiempirical methods

The Birch alkylation products are very unstable. We are showing, in this communication, the results of a theoretical study that compares different decomposition reaction mechanisms. The conclusions are in agreement with our experimental results.Facultad de Ciencias Exacta

Entanglement and quantum phase transition in the one-dimensional anisotropic XY model

In this paper the entanglement and quantum phase transition of the anisotropic s=1/2 XY model are studied by using the quantum renormalization group method. By solving the renormalization equations, we get the trivial fixed point and the untrivial fixed point which correspond to the phase of the system and the critical point, respectively. Then the concurrence between two blocks are calculated and it is found that when the number of the iterations of the renormalziation trends infinity, the concurrence develops two staturated values which are associated with two different phases, i.e., Ising-like and spin-fluid phases. We also investigate the first derivative of the concurrence, and find that there exists non-analytic behaviors at the quantum critical point, which directly associate with the divergence of the correlation length. Further insight, the scaling behaviors of the system are analyzed, it is shown that how the maximum value of the first derivative of the concurrence reaches the infinity and how the critical point is touched as the size of the system becomes large.Comment: 10 pages, 5 figure

Printers are dangerous

Proceeding of: IEEE 35th International Carnahan Conference on Security Technology, London , UK, 16 - 19 october 2001In the last years, many new intelligent full-featured peripherals that assist information systems have appeared. Those peripherals, such as printers, copiers, PDA organizers, Web cameras, etc. usually have a very friendly way of configuration and management (via http, ftp or telnet servers) and offer more networked services everyday. Their computation, memory and networking capabilities have also increased in the last years. Nowadays, many of them are comparable to workstations and run complete operating systems such as Linux or Solaris. All those factors imply that these devices could represent a real threat to the security of information systems. This problem is even worse because most of those peripherals have been considered inoffensive and not many administrators are aware of their security risks. The most representative example is printers, which have been traditionally considered totally harmless devices. At the present time, that idea is difficult to defend because many security incidents related with networked printers have arisen in the last years. System and security administrators have traditionally focused their efforts in fortifying servers and hosts only, but it seems that this view is not enough for assuring security nowadays.Publicad

A Family of Hybrid Space-Time Codes for MIMO Wireless Communications

Hybrid MIMO space-time codes combine the benefits of spatial multiplexing with diversity gain to achieve both high spectral efficiency and link reliability. In this paper, we present a family of hybrid codes, known as LD STBC-VBLAST codes, along with a receiver architecture suitable for low-complexity hardware implementation. We show that, under Rayleigh fading, the performance of LD STBC-VBLAST codes is superior to other recently proposed hybrid codes. We also present a technique to derive, from a given propagation scenario, spatially correlated MIMO channel models adequate for space-time coding performance analysis. Using this technique, we evaluate the performance of LD STBC-VBLAST codes under several correlated channels.ITESO, A.C.ITSONCINVESTAV-IPNPROME