1,776 research outputs found
Hertzian Fields: Exploring WiFi microwave signals as a spatial and embodied sensing medium for art
No full textThesis (Ph.D.)--University of Washington, 2023This dissertation is centered around a series of three artworks (Hertzian Fields) that explore WiFi as a spatial and embodied sensing medium. These works use a new sensing technique developed by the author that leverages the interference of the human body on WiFi signals to create highly responsive live performance and interactive systems. Hertzian Field #1 (2014) is an augmented reality immersive environment using sound to explore the materiality of WiFi communication through its interaction with space and the human body. Hertzian Field #2 (2016) is a 20'-25' augmented reality immersive performance for solo performer, WiFi fields, computers and surround sound that conjures a phenomenology of the hertzian medium explored through sound and movement. The Water Within (Hertzian Field #3 and #3.1) is a reactive wet sauna: an intimate multi-sensory environment of complete immersion, combining WiFi sensing fields, machine listening software, embedded 3D sound, hot steam, and architectural design. Steered by the flows and variable densities of water molecules traced in steam and bodies by (ab)using WiFi, it creates a regenerative post-relational experience that celebrates interference, signal-loss, and disconnecting. The piece exists in two iterations and formats: an interactive installation (2016) and a composed interactive experience (2018).
The dissertation describes the author's conceptual and technical approach in using WiFi microwave signals as an artistic medium. It also examines the background, context, ideas and research processes that led to the creation of these works. In doing so, it lays the foundation for developing a better and deeper understanding of microwaves and WiFi signals, investigates their artistic potential, and discusses related approaches by other artists.
Chapter One (Introduction: The hertzian medium) introduces core ideas and concepts regarding the medium. This includes: a discussion on the impact of wirelessness in contemporary living and how it has transformed our interactions with and understanding of the world; an overview of the physics of electromagnetism and the electromagnetic spectrum; and an investigation of the hertzian (i.e. radio and microwaves) as a multilayered medium consisting of seven interconnected layers: physics, science, imagination, engineering, use, impact, regulation.
Chapter Two (The birth of a medium: Energy becomes technology) introduces a media archaeological approach as a method for grasping what the medium affords, and how our imagination of what we can use it for has developed over time. It presents an overview of key developments in hertzian science, imagined and realized applications, and their impact. This chapter focuses primarily on the early years around Heinrich Hertz’s discovery of electromagnetism, looking at the birth of wireless technologies relevant to the Hertzian Field series: communication, broadcast, hacking and electronic warfare, navigation, meteorology, radio astronomy, and radar, before closing with a section on the development of WiFi.
Chapter Three (Radar and Direction-Finding in sonic art and beyond) surveys musical instruments and artworks based on spatial and/or embodied uses of the hertzian as a sensing medium. The emphasis is on sound-centric practices and specific technologies that have been used to this extent: from capacitative / electric field sensing, to musical instruments utilizing direction-finding principles, to spatial uses of broadcast radio, to doppler radar systems. Instruments discussed include: Theremin and Terpsitone; Pupitre d'Espace; Radio Baton; Marimba Lumina. Artworks by the following artists are examined: Max Neuhaus; Edwin van der Heide; Christina Kubisch; John Cage; Philippa Cullen; Liz Phillips; Sonia Cillari; Tetsuo Kogawa; Anna Friz; Edward Ihnatowicz; Steve Mann; Joe Paradiso / MIT Lab; Arthur Elsenaar; Godfried-Willem Raes.
Chapter Four (First hertzian explorations: From the network to the body, from WiFi to Radar) turns to the author's own work. It presents the first phase (2010-14) of his research trajectory on the hertzian medium, and introduces three projects in which he explored WiFi and broadcast radio.
Chapter Five (Ubiquitous sensing with radio waves and microwaves) dives into the technological context influencing the author's research. It introduces the field of Ubiquitous Sensing and discusses relevant localization and device-free sensing techniques, concluding with a discussion on the physics and biological factors involved so as to comprehend how and why such techniques work.
Chapter Six (Wireless Information Retrieval: Sensing with WiFi signals) presents the device-free WiFi-sensing technique that the author developed for the Hertzian Field series. Combining elements from Ubiquitous Sensing and Music Information Retrieval, this technique performs multi-layered feature extraction on the Received Signal Strength Indication (RSSI) of WiFi Beacon frames to deduce a variety of information related to the movement of uninstrumented bodies, and to changes in environmental factors (e.g. humidity).
Chapter Seven (Composing Hertzian Fields) discusses strategies for creating works with this technique, and examines the three works of the Hertzian Field series in detail. It finally touches on ideas for future work by the author
INTEGRAL detects the hard X-ray brightening of 4U 1630-47
No full textAuthors:- A. Bodaghee, A. Popp, V. Grinberg, A. Manousakis, M. Turler, E. Bozzo, C. Ferrigno, J. A. Tomsick, R. Duro, N. Hell, I. Miskovicova, M. Obst, J. Wilms, A. Lohfink, D. Marcu, Katja Pottschmidt, M. Cadolle Bel, E. Kuulkers, J. Rodriguez, R. Krivonos, J. Chenevez, A. Paizis, J. Kennea, P. Romano, P. R. den Hartog, N. Barriere, V. Beckmann, S. Soldihttps://astronomerstelegram.org/?read=394
La questione dell’autenticità del Prometeo Incatenato e le teorie del ‘falso’ eschileo
No full textSurvey on the question of Prometheus’ authorship, with a focus
on the story of plagiarism theories. According to Wilhelm Schmid, only
Prometheus Unbound was written by Aeschylus as Monodrama; an unknown
author (perhaps a metic from Ionia, strongly influenced by Aeschylus)
wrote Prometheus Bound, a ›Lesedrama‹ in imitation of the Unbound, a few
years before Sophocles’s Antigone and Ajax. Martin L. West identifies the author
with Euphorion, a son of Aeschylus, who wrote and staged the entire
tragic trilogy under his father’s name not earlier than the late 440s. Nikos
Manousakis, starting from statistical researches showing the affinity of the
language of Prometheus Bound with Sophocles, suggests that the author may
be Euaion, brother of Euphorion, who perhaps acted as an actor in Sophocles’
plays
Optimizing the role of impact ionization in conventional insulators
No full textA mechanism for multiple carrier generation through impact ionization (IA) proposed earlier for bulk systems of strongly correlated insulators is generalized to the case of conventional insulators that contain localized bands a few eV above and below the highest occupied band. Specifically, we study the case of hybridization of localized orbitals with more dispersive bands near the Fermi level, where the generated multiple carriers, which ultimately decay to the edges of the dispersive bands by means of IA processes, acquire lighter mass and this could allow their more efficient separation before recombination. We argue that this may be applicable to the case of halide perovskites and it could be one of the reasons for their observed photovoltaic efficiency. We discuss the criteria one should use to uncover the appropriate material in order to harvest the optimum effect of IA for the spectrum of the solar photon energy distribution. © 2019, The Author(s)
Devising Rhesus: A strange 'collaboration' between Aeschylus and Euripides
No full textIn recent years, one of the two fully preserved ancient Greek tragic plays of disputed authorship, Rhesus, traditionally attributed to Euripides, has been the object of a quite lively scholarly interest. The rather extreme number, for the standards of classical philology, of four published commentaries in 10 years, by Athanasios D. Stefanis, [Euripides']: Rhesus, Athens: Academy of Athens, 2004, Arne Feickert, Euripidis: Rhesus, Frankfurt: Lang, 2005, Vayos Liapis, A Commentary on the Rhesus Attributed to Euripides, Oxford: Oxford University Press, 2012, and Almut Fries, Pseudo-Euripides: Rhesus, Berlin: De Gruyter, 2014 (two of them in English), and one forthcoming by Marco Fantuzzi (also in English), tangibly prove the great vogue this drama enjoys nowadays. Its doubtful nature, as far as the fusion of tragic and comic elements is concerned (see further Burnett, Directions in Euripidean Criticism: A Collection of Essays, Durham: Duke University Press, pp. 13-51, 177-88, 1985), and, most of all, its controversial authorship and date still render it a riddle-even though its non-Euripidean origin is widely accepted. Our research is an attempt to unveil the authorial status of this play, employing traditional and non-traditional authorship attribution techniques. In fact, as it will become clear in the course of this work, the latter kind of methodology allows us to approach the author of Rhesus in a way that was not even thought possible until the present day. © The Author 2017
On the origin of matter-antimatter asymmetry in the Universe
No full textIn order to investigate the origin of matter-antimatter asymmetry in the Universe, we adopt a theoretical framework where the standard model emerges as a Poincaré invariant field theory localized at a domain-antidomain wall (DW-aDW) brane pair of a theory which lives on a higher dimensional bulk. We argue that such a system of a parallel DW-aDW pair could have been created at a very early epoch of the cosmological evolution when the Universe was still of microscopic size because its creation is topologically possible as compared to a single DW creation when the perpendicular extra dimension is compact. The conservation laws, such as of charge and chirality, are not violated in vacuum fluctuations of the combined DW-aDW system, but as we show their simultaneous conservation for each wall separately may not be favorable in certain processes. In particular, as expansion of spacetime occurs in the higher dimensional bulk, the distance d between the DW and the aDW increases as a function of time. We show that during the early stages of the cosmological evolution, when d was of microscopic size, the leading mechanism for pair-creation from fluctuations of the gauge-field with polarization perpendicular to the DWs (i.e., polarization along the extra dimension) was one in which the particle and the antiparticle were created on the opposite domain-walls hosting opposite chirality fermions. This mechanism allows for a matter-antimatter asymmetry to appear separately in the DW and the aDW, while in the combined DW-aDW system no such asymmetry was allowed. Momentum, energy, charge and parity conservation are all fulfilled if we consider the DW-aDW system together. In this scenario, at a later and the present stage of the cosmological evolution, where d is macroscopically large, the probability to violate these conservation laws on a single DW, as a function of the inter-wall distance, is exponentially suppressed. © 2022 The Author(s
Possible role of
No full textWe use a quantum lattice gas model to describe essential aspects of the motion of 4He atoms and of 3He impurities in solid 4He. This study suggests that 3He impurities bind to defects and promote 4He atoms to interstitial sites which can turn the bosonic quantum disordered crystal into a metastable supersolid. It is suggested that defects and interstitial atoms are produced during the solid 4He nucleation process where the role of 3He impurities (in addition to the cooling rate) is known to be important even at very small (1 ppm) impurity concentration. It is also proposed that such defects can form a glass phase during the 4He solid growth by rapid cooling
Simulação de monte carlo para uma partícula nanomagnética do tipo núcleo/casca
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-Graduação em Física, Florianópolis, 2013Neste trabalho foram estudadas as propriedades de um sistema magnético finito para modelar uma nanopartícula magnética formada por um número reduzido de momentos de dipolo magnético devido ao spin dos átomos. A nanopartícula é do tipo núcleo/casca, no qual a casca é formada por spins que interagem com outros spins da casca via interação de troca antiferromagnética enquanto para os spins do núcleo essa interação é ferromagnética. Na interface núcleo/casca a interação entre os spins do núcleo com spins da casca pode ser tanto ferro quanto antiferromagnética. Para descrever os possíveis estados de spin utilizamos o modelo XY para os spins, no qual os spins são considerados como variáveis continuas, livres para apontar em qualquer direção do plano xy. Além da interação de troca, consideramos a anisotropia magnetocristalina, a anisotropia de troca e o efeito Zeeman. Nosso modelo foi estudado em uma rede com simetria quadrada, utilizando o método de Monte Carlo com a prescrição de Metropolis. Os resultados obtidos mostram que, na ausência de campo magnético externo, e da anisotropia de troca, o sistema passa continuamente de um estado ordenado para um estado desordenado em uma temperatura bem definida. Na presença de campos magnéticos externos o sistema apresenta o fenômeno do deslocamento dos ciclos de histerese apenas quando da introdução do termo de anisotropia de troca. Entretanto, tal deslocamento depende dos tamanhos do núcleo e da casca e também da intensidade do acoplamento entre os momentos da casca e do núcleo <br
Implicit and Explicit Words of Wisdom in Aeschylus and in Prometheus Bound: A Laconically Generalizing Titan and a Densely Lavish Poet
No full textPrometheus Bound is a disputed play in the Aeschylean corpus. For some time now the impact of this short description seems to be gradually unraveling the renowned reputation this play used to enjoy. What was in the past the grandiose work of an eminent master, is now regarded by a rising number of scholars as a rather simplistic composition by an anonymous author. Yet, even though the disputed play could not have been composed by Aeschylus, and is indeed nothing like Aeschylus in the summit of his art, as we know him in the main through the fully extant dramas of the last fifteen or so years of his career, Pr. is not devoid of genuine dramatic value. In the present study I focus on the generalizations in the plays in the Aeschylean corpus. I attempt to show that even though the author of Pr. and Aeschylus are clearly different in how they exploit generalizations, this does not-ipso facto-imply that the anonymous former is incompetent in this respect, while the famous latter is most skillful. They are two different playwrights with two different, yet both very special, approaches in handling generalizations. © 2020 Walter de Gruyter GmbH, Berlin/Boston 2020
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