7,082 research outputs found

    Massive MIMO Full-Duplex Relaying with Optimal Power Allocation for Independent Multipairs

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    With the help of an in-band full-duplex relay station, it is possible to simultaneously transmit and receive signals from multiple users. The performance of such system can be greatly increased when the relay station is equipped with a large number of antennas on both transmitter and receiver sides. In this paper, we exploit the use of massive arrays to effectively suppress the loopback interference (LI) of a decode-and-forward relay (DF) and evaluate the performance of the end-to-end (e2e) transmission. This paper assumes imperfect channel state information is available at the relay and designs a minimum mean-square error (MMSE) filter to mitigate the interference. Subsequently, we adopt zero-forcing (ZF) filters for both detection and beamforming. The performance of such system is evaluated in terms of bit error rate (BER) at both relay and destinations, and an optimal choice for the transmission power at the relay is shown. We then propose a complexity efficient optimal power allocation (OPA) algorithm that, using the channel statistics, computes the minimum power that satisfies the rate constraints of each pair. The results obtained via simulation show that when both MMSE filtering and OPA method are used, better values for the energy efficiency are attained.Comment: Accepted to the 16th IEEE International Workshop on Signal Processing Advances in Wireless Communications - SPAWC, Stockholm, Sweden 201

    Retrospective comparative study of bone loss in implants with and without immediate loading in the Egas Moniz university clinic

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    To evaluate bone loss after three years in implants placed at the implantology consult at the Egas Moniz University Clinic, relating bone loss to the type of loading (conventional or immediate load). A comparative and retrospective study, performed on a sample of 65 implants, placed in 24 of 327 patients, who attended the implantology consult at the Egas Moniz University Clinic in 2015, representing 7.3% of the study population through the measurement of distance between implant platform and bone using radiographs. Three years after implant placement with and without immediate loading there is statistically significant bone loss mesially and distally. It was found that when compared bone loss in loaded vs unloaded mesially and distally implants, there were no statistically significant differences. The bone loss of the unloaded implants was compared three years after being placed, with the bone level of the loaded implants also three years later. No significant difference was found. Although no statistically significant differences were found between bone loss in loaded implants vs unloaded mesially and distally, as it is supported by the literature, it was possible to conclude that there was, in fact, a statistically significant bone loss, mesially and distally, three years after implant placement with and without immediate loading. This may be due to poor oral hygiene, a history of periodontitis, smoking and peri-implantitis.info:eu-repo/semantics/publishedVersio

    Does High Inflation Affect Growth in the Long and Short Run?

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    This paper investigates the relationship between inflation and output in the context of an economy facing persistent high inflation. By analyzing the case of Brazil, we find that inflation does not impact real output in the long run, but that in the short run there exists a negative effect from inflation on output. These results support Sidrauski’s (1967) superneutrality of money in the long run, but cast doubt on the short run implications of the model for separable utility functions in consumption and real money balances, as exposed by Fischer (1979). The results are more likely to support a class of utility functions in which real money balances and consumption are perfect complements.inflation; growth; output

    Contrôle biologique de la pourriture cendrée (Macrophomina phaseolina) du niébé par l’enrobage des semences avec Clonostachys rosea: Impact des conditions de conservation des semences traitées sur la performance du bioagent.

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    Dans les sols infestés avec Macrophomina phaseolina les semences de niébé ne germent pas ou bien la plantule est détruite plus ou moins rapidement après la germination. Clonostachys rosea est un champignon commun du sol reconnu comme un saprophyte avec une haute capacité de compétition sur les racines et dans le sol. Notre étude a pour objectif d’évaluer l’effet de C. rosea en traitement de semences du niébé conservées à 40°C sur le développement de la pourriture charbonneuse. L’effet de la durée de conservation sur la viabilité des spores et le pouvoir antagonique du bioagent a également été étudié dans les conditions semi contrôlé et au champ. Les isolats de C. rosea proviennent de la collection du laboratoire de phytopathologie de AGRHYMET. La production des spores a été effectuée sur le milieu PDA pendant 4 semaines. Les semences du niébé ont été traitées avec une suspension de spores à la concentration de 108 spores / ml à raison de 5 ml de suspension par kg de semences. Les semences traitées ont été séchées sous la hotte à flux laminaire pendant 2 h avant d’être semées ou conservées à 40°C. Des tests de viabilité des spores de C. rosea sur le milieu de culture PDA ont été effectués au laboratoire tous les 15 jours de conservation. Le taux de germination des semences sur papier buvard, évalué au cinquième jour après semis au laboratoire a été de 99 %. La forte moyenne de spores viables au jour de l’enrobage (J0) (>4,5 105), a chuté à 1700 spores par graines après 75 jours de conservation. En serre, le niveau de colonisation des tissus des plants de niébé se développant sur le sol infesté a été significativement plus faible chez les plants issus de graines enrobées (1009 microsclérotes/g tissus) que chez ceux issus de graines non enrobées (2356 microsclérotes/g tissus). Par rapport a la sévérité de la maladie, exprimée sur une échelle de 1-5, ont été notées une forte infection des plants du témoin Macrophomina (graines non traitées semées dans un sol infesté) et des attaques moins sévères sur les traitements G3M et G4M (graines traitées semées dans un sol infesté). Au champ dans l’essai semé avec des graines enrobées mais non conservées, l’association des isolats G3 et G4 a été nettement supérieure aux autres traitements par rapport aux rendements en fane et en graines. Par contre, par rapport au rendement, aucun effet des traitements n’a été observé dans l’essai semé avec les graines conservées pendant 30 jours

    Psicoterapia da depressĂŁo no idoso

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    Muitas das dificuldades do idoso são as dificuldades adiadas, e agravadas, do Homem da nossa cultura, que parece ter cortado relações com a morte e não conseguir aceitar a vida como algo que não controla em absoluto. Não surpreende, por isso, que também a intervenção junto do idoso possa replicar estas dificuldades, como num “acting-out contratransferencial colectivo”. Porque, efectivamente, proporcionar ao idoso uma relação terapêutica onde possa triangular os conteúdos altamente ameaçadores do confronto com a morte e transformá-los em conteúdos de relação, exige do terapeuta um convívio razoável com os seus próprios “temas existenciais”

    Full-Duplex Relaying in MIMO-OFDM Frequency-Selective Channels with Optimal Adaptive Filtering

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    In-band full-duplex transmission allows a relay station to theoretically double its spectral efficiency by simultaneously receiving and transmitting in the same frequency band, when compared to the traditional half-duplex or out-of-band full-duplex counterpart. Consequently, the induced self-interference suffered by the relay may reach considerable power levels, which decreases the signal-to-interference-plus-noise ratio (SINR) in a decode-and-forward (DF) relay, leading to a degradation of the relay performance. This paper presents a technique to cope with the problem of self-interference in broadband multiple-input multiple-output (MIMO) relays. The proposed method uses a time-domain cancellation in a DF relay, where a replica of the interfering signal is created with the help of a recursive least squares (RLS) algorithm that estimates the interference frequency-selective channel. Its convergence mean time is shown to be negligible by simulation results, when compared to the length of a typical orthogonal-frequency division multiplexing (OFDM) sequences. Moreover, the bit-error-rate (BER) and the SINR in a OFDM transmission are evaluated, confirming that the proposed method extends significantly the range of self-interference power to which the relay is resilient to, when compared with other mitigation schemes

    music to fall asleep in the construction of the domestic space

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    UID/EAT/00693/2019 SFRH/BD/136264/2018In order to celebrate World Sleep Day (March 15) in 2019, IKEA carried out several acts to raise people's awareness of the benefits of good sleep habits, and how their products can contribute effectively for the quality of sleep. In that context, Ikea Portugal shared on its Facebook page four playlists considered to be adequate to sleep "that 20-minute nap", have a quiet night's sleep or "a boost of morning energy to start the day". On YouTube, besides user-made playlists with the same purpose, original compositions are also produced and shared with the intent of provoking sleepiness/relaxation with the aim of a good night's sleep. In this paper, I propose to examine both the playlists created by IKEA Portugal and the compositions created and shared by users on YouTube with the intent to make you fall asleep, while analyzing the role of these compositions in the construction of the domestic space and a suitable environment for sleeping. For this, I take into account the everyday life seen as an element of culture production (Certeau 1998), built from a set of routines that unfold between objects and materials that construct the scenario where this staging of daily life occurs (Goffman 2002). Thus, I consider domestic spaces and their multisensorial dimension (Pink 2009) in which elements such as light, temperature, objects design and music collaborate in the construction of the desired environment (DeNora 2004). In methodological terms, I analyze the comments of YouTube users to the compositions in question, and the data obtained through surveys on the subject, broadcasted online.publishersversionpublishe
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