Infinite Factorial Finite State Machine for Blind Multiuser Channel Estimation

New communication standards need to deal with machine-to-machine communications, in which users may start or stop transmitting at any time in an asynchronous manner. Thus, the number of users is an unknown and time-varying parameter that needs to be accurately estimated in order to properly recover the symbols transmitted by all users in the system. In this paper, we address the problem of joint channel parameter and data estimation in a multiuser communication channel in which the number of transmitters is not known. For that purpose, we develop the infinite factorial finite state machine model, a Bayesian nonparametric model based on the Markov Indian buffet that allows for an unbounded number of transmitters with arbitrary channel length. We propose an inference algorithm that makes use of slice sampling and particle Gibbs with ancestor sampling. Our approach is fully blind as it does not require a prior channel estimation step, prior knowledge of the number of transmitters, or any signaling information. Our experimental results, loosely based on the LTE random access channel, show that the proposed approach can effectively recover the data-generating process for a wide range of scenarios, with varying number of transmitters, number of receivers, constellation order, channel length, and signal-to-noise ratio.Comment: 15 pages, 15 figure

Uniqueness for the inverse fixed angle scattering problem

We present a uniqueness result in dimensions $2$ and $3$ for the inverse fixed angle scattering problem associated to the Schr\"odinger operator $-\Delta+q$, where $q$ is a small real valued potential with compact support in the Sobolev space $W^{\beta,2}$ with $\beta>0.$ This result improves the known result, due to Stefanov, in the sense that almost no regularity is required for the potential. The uniqueness result still holds in dimension $4$, but for more regular potentials in $W^{\beta,2}$ with $\beta>2/3$

Can a Wi-Fi WLAN support a first person shooter?

In corporate and commercial environments, the deployment of a set of coordinated Wi-Fi APs is becoming a common solution to provide Internet coverage to moving users. In these scenarios, real-time services as online games can also be present. This paper presents a set of experiments developed in a test scenario where an end device moves between different APs while generating game traffic. A WLAN solution based on virtual APs is used, in order to make the handoffs transparent for Layer 3. The results show that it is possible to maintain an acceptable level of subjective quality during the handoff. At the same time, it is set clear that the fact of having a gamer in an AP could be taken into account by radio resource management algorithms, in order to provide a better quality

Synthesis, Characterization and Evaluation of the Cytotoxicity of Ni-Doped Zn(Se,S) Quantum Dots

Quantum dots (QDs) are semiconductor nanocrystals with desirable optical properties for biological applications, such as bioimaging and drug delivery. However, the potential toxicity of these nanostructures in biological systems limits their application. The present work is focused on the synthesis, characterization, and evaluation of the toxicity of water-stable Ni-doped Zn(Se,S) QDs. Also, the study of nondoped nanostructures was included for comparison purposes. Ni-doped nanostructures were produced from zinc chloride and selenide aqueous solutions in presence of 3-mercaptopropionic acid and Ni molar concentration of 0.001 M. In order to evaluate the potential cytoxicity of these doped nanostructures, human pancreatic carcinoma cells (PANC-1) were used as model. The cell viability was monitored in presence of Ni-doped Zn(Se,S) QDs at concentrations ranging from 0 μg/mL to 500 μg/mL and light excited Ni-doped Zn(Se,S) nanostructures were evaluated at 50 μg/mL. Results suggested that Ni-doped Zn(Se,S) nanostructures were completely safe to PANC-1 when concentrations from 0 μg/mL to 500 μg/mL were used, whereas non-doped nanostructures evidenced toxicity at concentrations higher than 200 μg/mL. Also, Ni-doped Zn(Se,S) QDs under light excitation do not evidence toxicity to PANC-1. These findings suggest strongly that Zn(Se,S) nanostructures doped with nickel could be used in a safe manner in light-driving biological applications and drug delivery

La potencialidad de la nube para el trabajo de campo en Geografía: el Parque Nacional de la Sierra de Guadarrama

El proyecto de innovación y mejora de la calidad docente “La potencialidad de la nube para el trabajo de campo en Geografía: El P.N. de la Sierra de Guadarrama” pretende contribuir positivamente a desarrollar la sensibilidad y el sentido ético de los estudiantes y el profesorado hacia los paisajes y los espacios naturales protegidos, desde la diversidad de nuevas tecnologías y geoinformación que disponemos en el presente. Se desarrolla una cartografía digital con puntos de interés didáctico en relación a los valores del espacio, naturales y culturales, con imágenes georreferenciadas para su localización desde la misma plataforma, el aula o el terreno, así como propuestas de actividades para los docentes

Compact full ku-band triplexer with improved e-plane power divider

An improved E-plane power divider for compact waveguide triplexers with large separation between channels is presented. The configuration of the divider aims to exploit the different behavior of the device for frequency bands with large separation, leading to a very asymmetric E-plane junction. H-plane filters with inductive windows are used for each channel, in order to obtain reduced insertion losses and lower sensitivity than in metal-insert E-plane filters. The resultant triplexer configuration is very compact, and its design is analyzed and optimized by Mode-Matching. The experimental results of a full Ku-band prototype for communications satellite systems show a very good agreement with the expected simulated response

Novel efficient genome-wide SNP panels for the conservation of the highly endangered Iberian lynx

Background: The Iberian lynx (Lynx pardinus) has been acknowledged as the most endangered felid species in the world. An intense contraction and fragmentation during the twentieth century left less than 100 individuals split in two isolated and genetically eroded populations by 2002. Genetic monitoring and management so far have been based on 36 STRs, but their limited variability and the more complex situation of current populations demand more efficient molecular markers. The recent characterization of the Iberian lynx genome identified more than 1.6 million SNPs, of which 1536 were selected and genotyped in an extended Iberian lynx sample. Methods: We validated 1492 SNPs and analysed their heterozygosity, Hardy-Weinberg equilibrium, and linkage disequilibrium. We then selected a panel of 343 minimally linked autosomal SNPs from which we extracted subsets optimized for four different typical tasks in conservation applications: individual identification, parentage assignment, relatedness estimation, and admixture classification, and compared their power to currently used STR panels. Results: We ascribed 21 SNPs to chromosome X based on their segregation patterns, and identified one additional marker that showed significant differentiation between sexes. For all applications considered, panels of autosomal SNPs showed higher power than the currently used STR set with only a very modest increase in the number of markers. Conclusions: These novel panels of highly informative genome-wide SNPs provide more powerful, efficient, and flexible tools for the genetic management and non-invasive monitoring of Iberian lynx populations. This example highlights an important outcome of whole-genome studies in genetically threatened species

Diseño de filtros de canal elípticos y autoEcualizados en banda Ka implementados en guía rectangular plano H

En esta comunicación se presenta un proceso sistemático de diseño de filtros de canal elípticos y autoecualizados en guía de onda rectangular y configuración plano-H en banda Ka. Se pretende desarrollar una alternativa a la configuración clásica dual-mode en guía de onda circular, con el objetivo de abaratar el coste y simplificar el proceso de producción. Para validar la metodología presentada se ha diseñado, fabricado y medido un filtro de orden seis con dos ceros de transmisión a frecuencias finitas para mejorar el rechazo y dos ceros de ecualización para el retardo de grupo. Los resultados experimentales validan el método propuesto

Analysis of the effect size of overweight in muscular strength tests among adolescents: Reference values according to sex, age, and body mass index.

The aim of this paper is to quantify the effect size of overweight on the results of muscular strength tests in adolescents and to report percentile tables based on sex, age, and body mass index (BMI). The study hypothesized that the effect size obtained from the difference between normal-weight and overweight youth would be greater than the differences between sexes within the same age group. A total of 11,044 Spanish adolescents (48.5% girls) aged 14.39 6 1.21 years (range: 12–16 years) from 42 secondary schools participated in the research. Muscular strength was evaluated using standing long jump, hand grip strength (manual dynamometer), and sit-ups (30 seconds). The effect size was analyzed using the adjusted Hedges’ g˘. The results show that 76.3 and 72.8% of overweight boys and girls, respectively, performed a standing long jump equal to or less than the normal-weight average. The 67.4 and 67.1% of overweight boys and girls, respectively, showed manual dynamometer values equal to or greater than the normal-weight average. Finally, 68.7 and 65.9% of overweight boys and girls, respectively, obtained measures for 30 seconds of sit-ups equal to or lower than the normal-weight average. It can therefore be concluded that the differential effect size between boys and girls is higher than that between normal-weight and overweight adolescents in the 3 strength tests analyzed. Despite the above, these results suggest the value of taking into account the BMI when assessing the muscular strength of young people, in addition to sex and age

Phase diagram of the (bosonic) Double-Exchange Model

The phase diagram of the simplest approximation to Double-Exchange systems, the bosonic Double-Exchange model with antiferromagnetic super-exchange coupling, is fully worked out by means of Monte Carlo simulations, large-N expansions and Variational Mean-Field calculations. We find a rich phase diagram, with no first-order phase transitions. The most surprising finding is the existence of a segment like ordered phase at low temperature for intermediate AFM coupling which cannot be detected in neutron-scattering experiments. This is signaled by a maximum (a cusp) in the specific heat. Below the phase-transition, only short-range ordering would be found in neutron-scattering. Researchers looking for a Quantum Critical Point in manganites should be wary of this possibility. Finite-Size Scaling estimates of critical exponents are presented, although large scaling corrections are present in the reachable lattice sizes.Comment: 17 pages, 14 figure