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

Portable low profile antenna at X-band

An antenna which has been conceived as a portable system for satellite communications based on the recommendations ITU-R S.580-6 and ITU-R S.465-5 for small antennas, i.e., with a diameter lower than 50 wavelengths, is introduced. It is a planar and a compact structure with a size of 40×40×2 cm. The antenna is formed by an array of 256 printed elements covering a large bandwidth (14.7%) at X-Band with a VSWR of 1.4:1. The specification includes transmission (Tx) and reception (Rx) bands simultaneously. The printed antenna has a radiation pattern with a 3dB beamwidth of 5°, over a 31dBi gain, and a dual and an interchangeable circular polarization

Mutual Coupling Reduction Techniques in Electronic Steering Antennas in X Band

This work provides the development of an antenna for satellite communications onboard systems based on the recommendations ITU-R S.580-6 [1] and ITU-R S.465-5 [2]. The antenna consists of printed elements grouped in an array, working in a frequency band from 7.25 up to 8.4 GHz (15% of bandwidth). In this working band, transmission and reception are included simultaneously. The antenna reaches a gain about 31 dBi, has a radiation pattern with a beam width smaller than 10oand dual circular polarization. It has the capability to steer in elevation through a Butler matrix to 4

Modular Planar Antenna at X-band for satellite communications

An antenna which has been conceived as a portable system for satellite communications based on the recommendations ITU-R S.580-6 [1] and ITU-R S.465-5 [2] for small antennas, i.e., with a diameter lower than 50 wavelengths, is introduced. It is a planar and a compact structure with a size of 40×40×2 cm. The antenna is formed by an array of 256 printed elements covering a large bandwidth (14.7%) at X-Band. The specification includes transmission (Tx) and reception (Rx) bands simultaneously. The printed antenna has a radiation pattern with a 3dB beamwidth of 5°, over a 31dBi gain, and a dual and an interchangeable circular polarizatio

Centro de gestión I+D+I en modalidad de coworking como espacios para la innovación

La idea generadora de este proyecto nace de la interpretación personal de cómo se entiende el programa a diseñar y teniendo siempre presentes las preexistencias de la zona y los conceptos de reutilización, renovación y revitalización, esenciales a la hora de entender el funcionamiento del Polígono de Argales. La intervención trata de poner en valor el espacio público. Busca llevar a cabo una nueva lectura de la forma de intervención en un tejido industrial haciendo del edificio adaptarles a las necesidades tecnológicas de la industrial, así como a los valores de confortabilidad de los usuarios. De esta manera se establece un interesante diálogo entre lo urbano y la plaza interna del edificio. Del análisis de la citada preexistencia dos son los aspectos que generarán la idea de proyecto: En primer lugar, la rotundidad de su perímetro. Se interviene de mediante muros de hormigón que delimitan los espacios. Su masividad simpleza casa perfectamente con el carácter fabril de la zona. Además, las roturas de los muros inciden en la idea de los flujos y recorridos penetrables hacia el interior. El segundo aspecto, en el que centro mi atención es la creación de un interior diáfano y adaptable cómo lo son las naves industriales. De esa funcionalidad nace un espacio central que organiza el edificio y sus recorridos. Aspecto que se contrapone a la masividad de los muros perimetralesGrado en Arquitectur

Caracterización de una lente zurda plana para la excitación de antenas planas de ranuras

“Metamaterials” are artificially engineered structured materials exhibiting novel properties due to their special architecture and not because of the constituent homogeneous materials used to manufacture them. This enables to design new materials with characteristics not available in conventional materials, as a negative refractive index. A new form of excitation for parallel plate slot antennas based in a planar “left handed” lens is proposed in [1]. This excitation allows enhancing the efficiency of these kinds of antennas. The lens is constructed using the well known “mushroom” structure. Here the characterization of the left handed lens with the mushroom structure in terms of their geometrical parameters (lattice constant, diameter of via, height of substrate) is presented using the dispersion diagram of the unit cell. Some simulations results are shown

For me, it was a liberation, like being free again. A qualitative approach to the care trajectories of divorced mothers in Spain

This article deals with the causes and consequences of divorce in a group of women with minor children in Spain, a country in Southern Europe that presents a pre-eminently familistic character based on a marked division of gender roles. We detected an imbalance between qualitative and quantitative studies on this topic, of which the latter are more numerous in the recently published literature. For this reason, here we wish to show the people behind the data by conferring two questions making up the analysis axes of this research. First, we deal with the causes of couple breakups, which are related to inequality in the distribution of housework and care tasks in all cases. Second, we analyse their speeches about work and family conciliation after divorce, with particular importance given to the presence, or not, of a strong family network

Study of materials and manufacturing technologies for an antenna distribution network in Ka band

A study for selecting the technology and material manufacturing for the distribution network of a low profile antenna in Ka band in order to provide Internet connection in commercial aircrafts through satellite link. It is presented the general structure of the network focused in new printed technologies for high frequencies such as Substrate Integrated Waveguide or Ridge Gap Waveguide. Simulated results for different dielectric materials in terms of transmission losses are provided

Low losses power distribution network at X band in stripline

An asymmetric stripline is proposed in this paper. The main aim of this line is to distribute the power among subarrays in an array with minimum losses. Several vertical transitions to subarrays are shown besides some network designs at X band for a square array for satellite communications

Cultura organizacional en la gestión de proyectos en la empresa constructora Obreval S.A.

Trabajo de gradoEl objetivo general del informe es conocer la percepción de la cultura organizacional y determinar el grado de madurez en gestión de proyectos de la CONSTRUCTORA OBREVAL S.A., haciendo uso del estándar internacional ISO 21500 y hacer la propuesta necesaria para que la empresa adopte ésta metodología que le permitirá obtener una ventaja competitiva en el mercado de la construcción.EspecializaciónEspecialista en Gerencia de Obras Civile