Full-duplex MIMO and PLNC for the Y-network

This paper considers a multi-way wireless network with three terminals which want to exchange or share data with the help of a relay: each terminal has some information that wants to transmit to the other two. The traditional way of doing this exchange either involves time-domain multiplexing (TDMA) or dedicated frequency-domain disjoint channels, at the expense of high bandwidth inefficiency. With the advent of network coding, and later physical-layer network coding, it became possible to reduce the number of time slots required to exchange the information between all the terminals. Moreover, using multiple-input multiple-output (MIMO) terminals and relays, the time-usage efficiency can be further boosted by transferring the burden from the time-domain to the spatial-domain via spatial multiplexing. This paper proposes the concatenation of the aforementioned techniques along with loopback interference cancellation, which recently became a central topic for the next generation of the physical-layer of wireless communications. The paper shows a protocol and techniques that allow all the information exchange between terminals to be reduced from the 6 time-slots, required in traditional TDMA, to one time-slot only, provided that the information packets are not too short. The error performance of this system is shown by means of simulation using MIMO Rayleigh fading channels.info:eu-repo/semantics/acceptedVersio

URLLC with coded massive MIMO via random linear codes and GRAND

A present challenge in wireless communications is the assurance of ultra-reliable and low-latency communication (URLLC). While the reliability aspect is well known to be improved by channel coding with long codewords, this usually implies using interleavers, which introduce undesirable delay. Using short codewords is a needed change to minimizing the decoding delay. This work proposes the combination of a coding and decoding scheme to be used along with spatial signal processing as a means to provide URLLC over a fading channel. The paper advocates the use of random linear codes (RLCs) over a massive MIMO (mMIMO) channel with standard zero-forcing detection and guessing random additive noise decoding (GRAND). The performance of several schemes is assessed over a mMIMO flat fading channel. The proposed scheme greatly outperforms the equivalent scheme using 5G’s polar encoding and decoding for signal-to-noise ratios (SNR) of interest. While the complexity of the polar code is constant at all SNRs, using RLCs with GRAND achieves much faster decoding times for most of the SNR range, further reducing latency.info:eu-repo/semantics/acceptedVersio

Spin configurations in hard-soft coupled bilayer systems: from rigid magnet to exchange spring transitions

We investigate equilibrium properties of an exchange-spring magnetic system constituted of a soft layer (e.g. Fe) of a given thickness on top of a hard magnetic layer (e.g. FePt). The magnetization profile M(z) as a function of the atomic position ranging from the bottom of the hard layer to the top of the soft layer is obtained in two cases with regard to the hard layer: i) in the case of a rigid interface (the FePt layer is a single layer), the profile is obtained analytically as the exact solution of a sine-Gordon equation with Cauchy's boundary conditions. Additional numerical simulations also confirm this result. Asymptotic expressions of M(z) show a linear behavior near the bottom and the top of the soft layer. In addition, a critical value of the number of atomic planes in the soft layer, that is necessary for the onset of spin deviations, is obtained in terms of the anisotropy and exchange coupling between the adjacent plane in the soft layer. ii) in the case of a relaxed interface (the FePt layer is a multilayer), the magnetization profile is obtained numerically for various Fe and FePt films thicknesses and applied field.Comment: 10 pages, 9 figures, PRB submitted (12-07-2010

Mechanisms of social buffering of fear in zebrafish

The supplementary materials such the videos, are not present in the deposit due to incompatibilty of the extension of the files with the repository.Some humans thrive whereas others resign when exposed to threatening situations throughout life. Social support has been identified as an important modulator of these discrepancies in human behaviour, and other social animals also exhibit phenomena in which individuals recover better from aversive events when conspecifics are present - aka social buffering. Here we studied social buffering in zebrafish, by exposing focal fish to an aversive stimulus (alarm substance - AS) either in the absence or presence of conspecific cues. When exposed to AS in the presence of both olfactory (shoal water) and visual (sight of shoal) conspecific cues, focal fish exhibited a lower fear response than when tested alone, demonstrating social buffering in zebrafish. When separately testing each cue's effectiveness, we verified that the visual cue was more effective than the olfactory in reducing freezing in a persistent threat scenario. Finally, we verified that social buffering was independent of shoal size and coincided with a distinct pattern of co-activation of brain regions known to be involved in mammalian social buffering. Thus, this study suggests a shared evolutionary origin for social buffering in vertebrates, bringing new evidence on the behavioural, sensory and neural mechanisms underlying this phenomenon.info:eu-repo/semantics/publishedVersio

A concern visualization approach for improving MATLAB and octave program comprehension

The literature has pointed out the need for focusing efforts to better support comprehension of MATLAB and Octave programs. Despite being largely used in the industry and academia in the engineering domain, programs and routines written in those languages still require efforts to propose approaches and tools for its understanding. Considering the use of crosscutting concerns (CCCs) to support the comprehension of object-oriented programs, there is room of its use in the context of MATLAB and Octave programs. The literature has purpose and examples in this direction. Considering this scenario, we propose the use of visualization enriched with CCCs representation to support the comprehension of such programs. This paper discusses the use of a multiple view interactive environment called OctMiner in the context of two case studies to characterize how collected information relating to crosscutting concerns can foster the comprehension of MATLAB and GNU/Octave programs. As a result of the conducted case studies, we propose strategies based on OctMiner and tailored to support different comprehension activities of programs written in MATLAB and Octave.info:eu-repo/semantics/acceptedVersio

Scaffolding MATLAB and octave software comprehension through visualization

Multiple view interactive environments (MVIEs) provide visual resources to support the comprehension of a specific domain dataset. For any domain, different views can be selected and configured in a real time fashion to be better adjusted to the user needs. This paper focuses on the use of a MVIE called OctMiner to support the comprehension of MATLAB and GNU/Octave programs. The authors conducted a case study to characterize the use of OctMiner in the context of comprehension activities. Results provide preliminary evidence of the effectiveness of OctMiner to support the comprehension of programs written in MATLAB and Octave.info:eu-repo/semantics/acceptedVersio

A multiple view interactive environment to support MATLAB and GNU/Octave program comprehension

Program comprehension plays an important role in Software Engineering. In fact, many of the software lifecycle activities depend on program comprehension. Despite the importance of MATLAB and Octave programing languages in the Engineering and Statistical communities, little attention has been paid to the conception, implementation and characterization of tools and techniques for the comprehension of programs written in these languages. Considering this scenario, this paper presents a Multiple View Interactive Environment (MVIE) called OctMiner that supports the comprehension of programs developed in the aforementioned languages. OctMiner provides a set of coordinated visual metaphors that can be adjusted in accordance with the comprehension goals. An example is presented to illustrate the main functionalities of OctMiner in a real scenario of program comprehension.info:eu-repo/semantics/acceptedVersio

Multiple Polyposis of the Gallbladder. Diagnostic Difficulties About One Case

Descreve-se um caso de uma doente de 52 anos de idade, submetida a colecistectomia com o diagnóstico de litiase biliar, baseado na colecistografia oral. No decurso do acto cirúrgico, em que não se palparam cálculos, o diagnóstico inicial foi posto em dúvida. A identificação da polipose múltipla só foi possível após colecistectomia. Com base na experiência colhida neste caso, faz-se uma revisão dos critérios diagnósticos e fundamenta-se a orientação terapêutica, dado o potencial de malignidade destas lesões