151398 research outputs found
Sort by
Cell-free massive MIMO-based physical-layer authentication
No full textIn this paper, we exploit the cell-free massive multiple-input multiple-output (CF-mMIMO) architecture to design a physical-layer authentication (PLA) framework that can simultaneously authenticate multiple distributed users across the coverage area.Our proposed scheme remains effective even in the presence of active adversaries attempting impersonation attacks to disrupt the authentication process. Specifically, we introduce a tag-based PLA CF-mMIMO system, wherein the access points (APs) first estimate their channels with the legitimate users during an uplink training phase. Subsequently, a unique secret key is generated and securely shared between each user and the APs. We then formulate a hypothesis testing problem and derive a closed-form expression for the probability of detection for each user in the network. Numerical results validate the effectiveness of the proposed approach, demonstrating that it maintains a high detection probability even as the number of users in the system increases
<i>Lo demás preguntad a mi poesía</i>: Lope de Vega and the ‘Epístola de Amarilis a Belardo’ (1621)
No full textThough published in Spain in Lope de Vega’s La Filomena (1621), the ‘Epístola de Amarilis a Belardo’ is attributed to an anonymous seventeenth-century Peruvian female poet and commands a key position in the history of colonial Latin American women’s writing. This article insists upon the recontextualisation of the work within La Filomena alongside the response piece with which it was originally twinned – Lope’s ‘Epístola de Belardo a Amarilis’ – and advocates forms of close reading which prioritise inter-/intratextuality and metaliterarity as key to its interpretation. What emerges is a game of literary ‘whodunnit’ to which the (thinly veiled) answer is always Lope
Phonetic cues to question intonation in Belfast English
No full textThis paper presents a perception experiment designed for Belfast English to discover whether listeners rely on pitch cues to differentiate declarative questions, i.e. those with no lexical nor syntactic marker cue to their question status, from statements. Belfast English is characterised by a rising nuclear pattern in both statements and questions, and the experiment explores whether the height of the nuclear pitch peak and the size of the excursion of the nuclear rise relates to the perception of the utterance as a statement or a question.A series of context-free utterances with various pitch manipulations was presented to thirty listeners, and results suggest that high peaks and large pitch excursions are strongly related to perception of the utterance as a question, irrespective of lexical and syntactic cues, and that low peaks and small excursions are related to perception of the utterance as a statement. Nonetheless, there is no distinct dividing line between the two. This observation contributes to discussions on Belfast English, and Urban Northern British intonation, as well as of gradient and categorical perception and meaning in intonation, and offers additional evidence for the ‘myth’ of categorical perception (see, for instance, McMurray, 2022).<br/
Place and brand names in contemporary Breton media: French borrowings and official prescription
No full textInvestigating the links between language and identity among speakers of the minoritised languages of France offers insight into how these speakers react to the linguistic dominance of French. This paper focuses on Breton, drawing on the category of ‘néo-bretonnants’, speakers who acquire Breton through formal education and/or later in life; these speakers are said to be more prepared to use Breton beyond their local communities and to prefer a re-Celticized lexis over the French borrowings used by traditional speakers. The study investigates how this plays out in the Breton found in a selection of media sources, focusing on place names and the names of brands and organizations. While much of the variation observed on a broad level can be related to differences in subject matter, the data also reveal that the level of conformance with stereotypical ‘néo-bretonnant’ practices can vary, and that there is room for lexical variation, indicating a range of attitudes on the part of speakers towards how the language should be used.<br/
From curiosity to convenience: the role of AI in higher education in an age of student impatience
No full textFrequency-diverse bunching metasurface antenna for microwave coincidence imaging
No full textA frequency-diverse bunching metasurface antenna (FDBMA) that can be used for microwave coincidence imaging (MCI) is proposed in this paper. The proposed FDBMA consists of two distinct types of apertures: the bunching aperture and the random aperture. A triple-layer-metal-baffle (TLMB) is designed to partition different apertures and improve the bunching characteristic. The bunching aperture is formed by a seven-element patch antenna array, which generates the bunching beam. Additionally, the random aperture comprises a random modulated metasurface along with twelve evenly distributed patch antennas serving as excitation sources. The random apertures superpose the frequency-diverse random beams on the bunching beam, thereby achieving the low-correlated frequency-diverse bunching radiation patterns. Low-correlated radiation patterns can be used as different measurement modes, which ensures the feasibility of MCI. The proposed FDBMA is verified through full-wave simulations