6,199 research outputs found
Compact optical transmitters for CubeSat free-space optical communications
No full textWe present the results of an architectural trade study and prototype implementation of an optical transmitter suitable for resource-constrained CubeSats. Recent advances in CubeSat attitude determination and control systems have made it possible to achieve three-axis stabilization. This is essential for laser communications systems, which have challenging pointing and stability requirements. Our downlink terminal design fits in a 10 cm x 10 cm x 5 cm volume, uses < 10W of power, weighs < 1 kg, and supports data rates up to 50 Mbps. The terminal incorporates pointing, tracking and acquisition optics, an optical fine-steering mechanism, and a compact transmitter. This work focuses on the development of the transmitter for the Nanosatellite Optical Downlink Experiment (NODE). Two transmitter architectures were considered initially: direct modulation of a high-power laser diode and a master oscillator power amplifier (MOPA). The MOPA-based approach was selected and a prototype 'breadboard' was built from commercially available components. The prototype transmitter produces high fidelity (extinction ratio, ER < 33 dB) pulse position modulation (PPM) waveforms at 1550nm with 200mW average output power while consuming 6:5W of electrical power. Keywords: free-space optical communications, CubeSat, small satellites, optical transmitters, lasercomUnited States. National Aeronautics and Space Administration (Space Technology Research Fellowship Program)JPL Strategic University Research Partnership
Single-Polarization Cladding-Pumped Optical Amplifier Without Polarization-Maintaining Gain Fiber
No full textWe demonstrate a single-polarization cladding-pumped Er : Yb optical amplifier using a dual-pass design with a Faraday rotator mirror and nonpolarization-maintaining gain fiber. Over a 25-nm range centered at 1562 nm, the amplifier output exceeds 1 W and maintains a polarization extinction ratio greater than 22 dB. We investigate enhanced relative intensity noise inherent in the dual-pass configuration and discuss scaling to higher powers
WDM laser transmitters for mobile free-space laser communications
No full textWe describe the performance of versatile high-performance multi-rate WDM laser transmitters using next-generation compact high-extinction-ratio power-efficient (CHERPe) transmitter designs. These leverage periodic time-frequency windowing of directly modulated laser signals to efficiently generate nearly ideal WDM waveforms with only mW-class drive power. facilitating WDM-channelization and providing straightforward access to many THz of available optical spectrum with low-bandwidth electronics. Furthermore, this approach can support scalable multi-rate operation with good power-and photon-efficiency and enable new architectural options. This approach is attractive for numerous applications and systems ranging from small airborne or CubeSAT-sized communication payloads to larger interplanetary lasercom platforms.Office of the Assistant Secretary of Defense for Research and Engineering (Contract FA8721-05-C-0002
O foco narrativo na ficção contemporânea : uma leitura de Author, Author, de David Lodge
No full textOrientador : Prof. Dr. Caetano Waldrigues GalindoAutor não autorizou a divulgação do arquivo digitalDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Humanas, Letras e Artes, Programa de Pós-Graduação em Letras. Defesa: Curitiba, 26/06/2013Bibliografia: fls. 158-161Área de concentração: Estudos LiteráriosResumo: O propósito deste trabalho é refletir sobre a construção do foco narrativo em Author, Author (2004), de David Lodge, romance biográfico sobre o escritor Henry James (1843-1916). O narrador não se limita a situar o leitor na narrativa: o seu posicionamento em relação aos aspectos factuais da vida e do percurso literário do romancista norte-americano desempenha papel fundamental na discussão das estratégias narrativas da prosa de ficção de James. Na construção ficcional do malogro na noite de estreia de Guy Domville, em Londres, em 1895, por exemplo, é possível perceber a bipartição desse narrador, capaz de contar e mostrar dois episódios que se passam em dois lugares diferentes, simultaneamente. Em outros momentos do romance, a voz autoral embaralha-se com a voz do sujeito da enunciação a tal ponto, que o leitor menos atento encontra certa dificuldade para colocar ordem nos discursos. O abandono gradual da prosa de ficção em busca de uma identidade como dramaturgo, a falta de êxito na dramaturgia, a lenta recuperação psicológica, a retomada da prosa de ficção e o resultado insatisfatório da revisão e escrita de prefácios para as suas obras, para compor The novels and tales of Henry James:The New York Edition (1905), são alguns dos desdobramentos da trajetória de James, discutidos em Author, Author.Abstract: The purpose of this dissertation is to think over the construction process of narrative focus in Author, Author (2004), by David Lodge, a biographical novel about the writer Henry James (1843-1916). The narrator does not limit himself to guiding the reader through the narrative; rather, his attitude towards factual aspects of the life and literary course of the North-American novelist seems to play a fundamental role in the novel. In the fictional construction of the débâcle of "Guy Domville", in London, 1895 for instance it is possible to distinguish the narrator's bipartition, in order to tell and show two different episodes which happen in two different places, simultaneously. In other moments, the authorial voice blends with that of the subject of the enunciation to such a degree that the less attentive reader may not be capable of organizing the discourse, in a first moment. James' gradual movement away from prose fiction so as to find his playwright identity; the lack of success as a playwright; his subsequent slow psychological recovery; the return to prose fiction; and, finally, the weak result of writing and revising prefaces to his literary works in order to put together The Novels and Tales of Henry James: The New York Edition (1905), are some of the most conspicuous events in James' trajectory discussed in Author, Author
Cult: A Composite Novel
No full textCult (redacted)
The first component of the thesis is a composite novel called Cult which falls into two parts with seven narratives in each. Part 1 tracks the protagonist, Ellen, from her first involvement with the cult through to her eventually leaving it. Although fiction, the first half of the book answers the kinds of questions the author is asked when people discover that she was once a sannyasin (a follower of the guru Bhagwan Shree Rajneesh). While the experiences of meditation, group therapy and communal living are all faithfully rendered within the stories, the need for strong characters, narrative drive and a lightness of touch takes precedence.
Part 2 picks up Ellen’s story some twenty or so years later and explores what becomes of her in middle age. It also looks at other groups in society, such as academia, the law and the internet dating community which each have their own jargon, hierarchies, rituals and rules but are not considered to be cults.
The book examines the question raised in the Epigraph, ‘how do we be together when we feel so alone’ with a focus on relationships other than the familial and the romantic.
Collisions, Chasms and Connections: a Performative Exploration of the Composite Novel Form
The second part of the thesis is both a critical and creative response to three contemporary American books: Olive Kitteridge by Elizabeth Strout; A Visit from the Goon Squad by Jennifer Egan; and Legend of a Suicide by David Vann. The critical element comprises a close reading of the three books; a chronological reconstruction of their overarching storylines; and a consideration of what their authors have said about writing the books. It concludes that, in the composite novel, the simultaneous presentation of multiple views and storylines operate much like a 3D image to give the impression of depth to the characters and situations rendered. The creative element of the essay is a playful and personal response to the texts
(Re)Making of Identity: A Socio-Cultural Analysis of David Mamet’s American Buffalo
No full textThis article delves into the assertion of identity in David Mamet’s famous play American Buffalo. Mamet has revealed a rich variety of possible variations of identity in his creative opus, not only in the field of drama and theatre but also in the film, through the portrayal of a variety of different characters and situations. The identity will be discussed in his play as a unique cultural text outside of which there is nothing. America, its myths and contemporary cultural industry, its class, racial, and gender conflicts, and the author establish a mutual set of influences that help characters formulate their identities. By using Stuart Hall’s idea of identity in flux, this qualitative research explores the effects of industrialization on psychology, the concept of success of the people, and their identity in general. The change from ‘Who am I’ to ‘What do I have’ is the concern of the American people in this post-modern era so it has been given special focus. To some extent, the identity of the characters, if it means material success in his plays, is linked with the American Dream. The research also aims at the means i.e. language, lies, maltreatment, double-crossing, and cheating, the Mametian characters adopt to formulate their identity. The analysis shows that if identity means material success, they never succeed in making their identity. They keep on making, remaking, and re-remaking their identity proving that identity in the world of Mamet is in flux
Implementation and validation of a CubeSat laser transmitter
No full textThe paper presents implementation and validation results for a CubeSat-scale laser transmitter. The master oscillator power amplifier (MOPA) design produces a 1550 nm, 200mW average power optical signal through the use of a directly modulated laser diode and a commercial fiber amplifier. The prototype design produces high-fidelity M-ary pulse position modulated (PPM) waveforms (M=8 to 128), targeting data rates > 10 Mbit/s while meeting a constraining 8W power allocation. We also present the implementation of an avalanche photodiode (APD) receiver with measured transmitter-to-receiver performance within 3 dB of theory. Via loopback, the compact receiver design can provide built-in self-test and calibration capabilities, and supports incremental on-orbit testing of the design.United States. Air Force. Assistant Secretary of Defense for Research & Engineering (Air Force Contract #FA8721{05{C{0002
David Lodge and Authorial Control: (Self-)Positioning and Anxiety of Reception in the Field of Biographical Fiction
No full textThe status of authorship had been greatly diminished under the influence of poststructuralist theory about the author, which resulted in an authorial loss of control. However, authorship recently seems to have found its way back into the evaluation of literature. For instance, authorship has gained attention through foregrounding the author as a novelistic character. Fictionalised accounts of the life of an author have become increasingly popular in recent decades, like David Lodge’s Author, Author (2004) and A Man of Parts (2011). These two novels (re-)connect the author to his work, and thereby recentralise the author. In addition, they show that David Lodge is also struggling with authorial control. This thesis explores and discusses three themes in relation to David Lodge and authorial control, within these two novels and outside of them: the return of the author as a novelistic character, self-positioning of the author, and anxiety of reception
The future of scholarly communications
No full textThe academic publishing industry is set to celebrate 350 years of peer-reviewed scientific journals. However, there are significant shifts in the practice of scholarship, as scholars and citizens alike participate in an increasingly digital world. Is the scholarly article still fit for its purpose in this data-driven world, with new interdisciplinary methodologies and increasing automation? How might it be enhanced or replaced with new kinds of digital research objects , so as not to restrict innovation but rather create a flourishing sense-making network of humans and machines? The emerging paradigm of social machines provides a lens onto future developments in scholarship and scholarly collaboration, as we live and study in a hybrid physical-digital sociotechnical system of enormous and growing scale.Copyright 2014 David De Roure. This is an open access article distributed under the terms of the Creative Commons Attribution Licence, http://creativecommons.org/licenses/by/4.0/ which permits unrestricted use and distribution provided the original author and source are credited. If reusing please acknowledge "Insights: the UKSG journal" as the place of first publication. Please cite using the full DOI as specified at the end of the article: De Roure, D, The future of scholarly communications, Insights, 2014, 27(3), 233–238; DOI: http://dx.doi.org/10.1629/2048-7754.17
David Machado: um passaporte para o sonho
No full textMestrado em Línguas, Literaturas e CulturasEsta dissertação tem como principal objetivo uma análise sistemática da obra infanto-juvenil de David Machado, inserida no contexto da literatura portuguesa contemporânea de potencial recetor infantil.
O presente estudo irá contemplar, assim, uma pequena biografia e uma breve contextualização do autor e da obra. Analisar-se-á um corpus composto pelas suas cinco obras escritas para a infância, explorando as diferentes categorias da narrativa, salientando os aspetos oníricos que as percorrem e far-se-á, num segundo momento, uma análise crítica das ilustrações que acompanham cada conto.
A partir da análise desse corpus serão retiradas as conclusões que permitirão identificar o sonho como o tema que percorre toda a obra do escritor, uma esécie de passaporte mágico para ultrpassar os limites da existência e as fronteiras da realidade.
Será ainda possível identificar as características e o estilo do autor que contrói argumentos narrativos que combinam, de forma hábil, o universo realista com o maravilhoso, explorando as vertentes da fantasia e da imaginação.This thesis aims at a systematic analysis of children's literature authored by David Machado, in the context of contemporary Portuguese literature for potential children readers.
This study will thus provide a short biography and a brief background of the author and his work. A corpus made up of his five works written for children will be analysed, exploring the different narrative categories, and emphasizing the dreaming aspects that run through them all. Subsequently, a critical analysis of the illustrations that accompany each tale will also be presented.
After the analysis of this corpus, conclusions will be drawn identifying dreming as the main theme that runs through the entire writer's work, as if it is a magical passport which allows one to go beyond all existence and reality boundaries.
The characteristics and style of the author who builds his narrative arguments so skilfully, combining the realistic with the wonderful universe, and exploring fantasy and imagination facets will also be identified
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