Encoding by control of the symbolic dynamics emitted by a chaotic laser

Application to a chaotic erbium-doped fiber laser of the digital encoding technique by control of its emitted symbolic dynamics is numerically tested. Criteria to select the better working conditions and the perturbation to be introduced in any control parameter are proposed. Once they are chosen, the procedure to prepare the system for control and the way to carry it out are described. It is shown that the general method cannot be blindly applied, but it must be adapted to the particular case under analysis for a good performance. Finally, in relation to a possible experimental implementation, influence of noise in the bit error rate of the communication system is discussed

Latent Dirichlet Allocation (LDA) for improving the topic modeling of the official bulletin of the spanish state (BOE)

Since Internet was born most people can access fully free to a lot sources of information. Every day a lot of web pages are created and new content is uploaded and shared. Never in the history the humans has been more informed but also uninformed due the huge amount of information that can be access. When we are looking for something in any search engine the results are too many for reading and filtering one by one. Recommended Systems (RS) was created to help us to discriminate and filter these information according to ours preferences. This contribution analyses the RS of the official agency of publications in Spain (BOE), which is known as "Mi BOE'. The way this RS works was analysed, and all the meta-data of the published documents were analysed in order to know the coverage of the system. The results of our analysis show that more than 89% of the documents cannot be recommended, because they are not well described at the documentary level, some of their key meta-data are empty. So, this contribution proposes a method to label documents automatically based on Latent Dirichlet Allocation (LDA). The results are that using this approach the system could recommend (at a theoretical point of view) more than twice of documents that it now does, 11% vs 23% after applied this approach

Numerical method for analysis of the correlation between ferrofluid optical transmission and its intrinsic properties

A numerical method to simulate the ferrofluid particle distribution evolution is presented. Also, the optical transmission of the distributions obtained is calculated by two numerical methods. The first one consists on a numerical propagation of an electromagnetic wave through the sample. The second one analyzes the aggregates’ mean length to obtain the optical transmission through a mixture law. As an illustration of the possibilities of the method developed, it is applied to analyze how ferrofluid optical transmission changes after magnetic field application depend on intrinsic properties of the colloid such as its nanoparticle concentration and surfactant repulsion represented by means of the final distances between consecutive particles forming chains. Changes in the attenuation factor of these samples show the trends expected from the Literature

Analysis of the optical transmission of a ferrofluid by an electromagnetic mixture law

Evolution of the optical transmission of a ferrofluid after magnetic field commutation is analyzed by means of an approach based on the so-called mixture laws: expressions which predict the effective permittivity of heterogeneous media as a function of their constituents' permittivities, their proportions and the way they are arranged. In particular, this work is based on a law proposed by Sihvola and Kong for the effective permittivity of a host substance with ellipsoidal inclusions. Ferrofluids are peculiar examples of this kind of media: with the solvent as host, the inclusions are nanoparticle agglomerates whose shapes become modified by magnetic field exposure. In this work, experimental optical transmission of a ferrofluid is compared with predictions based on Sihvola and Kong''s law. A remarkable coincidence is obtained both in the absence of magnetic field, without using any fitting parameter, and in the presence of magnetic field, employing the inclusions' average ellipticity as the fitting parameter. The results obtained for time dependent optical transmission of a ferrofluid after magnetic field switch on or off allow one to estimate how the average shape of the agglomerates evolves over time. On the other hand, mixture laws are proven to be an interesting alternative to scattering concepts to model the optical transmission changes experienced by ferrofluids once they are exposed to magnetic fields

Late Miocene Mediterranean desiccation: topography and significance of the 'Salinity Crisis' erosion surface on-land in southeast Spain: Reply

We welcome this opportunity to amplify the results of our studies of the Late Miocene Messinian sequence in the Sorbas Basin of southeast Spain. The Salinity Crisis concept has captured geological imagination and found its way into textbooks, but scrutiny reveals its details to be disturbingly elusive. Our approach has been to read the history of this important episode in Neogene history in well-exposed on-land sections at Sorbas, Almería, near the western end of the Mediterranean. The Salinity Crisis concept, as it was first proposed (Hsü et al., 1973, 1977) and has largely survived (Cita, 1991), is of deep-desiccation and reflooding of the Mediterranean near the close of the Miocene. Marine downdraw resulted in marginal erosion; evaporites accumulated in depressions; and final marine reflooding completed the cycle. Our rationale is that if these principal tenets of the concept are correct, then one or more of their effects should be recorded throughout the region, both on the deep Mediterranean floor and in marginal basins that were contemporaneously connected to the Mediterranean, including the Sorbas Basin. This emphasis on the widespread effects of the Salinity Crisis does not exclude the possibility that they were overprinted by local conditions, which probably differed considerably over a region as extensive and diverse as the Mediterranean basins. Indeed, we have interpreted the evaporites of the Sorbas Basin to be local products of basin barring, related to the Salinity Crisis but not coeval with deep Mediterranean evaporites. At the same time, we have taken the view that the regional result of the Salinity Crisis in all marginal basins should be an erosion surface on the scale of the massive sea-level fall implied by the concept. It is our recognition of this erosion surface in the Sorbas Basin that has drawn most criticism from Fortuin et al. (2000). Here we provide further details of critical localities so that our observations can be accurately assessed