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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Overview of LBTI: a multipurpose facility for high spatial resolution observations

Hinz, P. M., Defrère, D., Skemer, A., Bailey, V., Stone, J., Spalding, E., Vaz, A., Pinna, E., Puglisi, A., Esposito, S., Montoya, M., Downey, E., Leisenring, J., Durney, O., Hoffmann, W., Hill, J., Millan-Gabet, R., Mennesson, B., Danchi, W., Morzinski, K., Grenz, P., Skrutskie, M., Ertel, S. 04 August 2016 (has links)
The Large Binocular Telescope Interferometer (LBTI) is a high spatial resolution instrument developed for coherent imaging and nulling interferometry using the 14.4 m baseline of the 2x8.4 m LBT. The unique telescope design, comprising of the dual apertures on a common elevation-azimuth mount, enables a broad use of observing modes. The full system is comprised of dual adaptive optics systems, a near-infrared phasing camera, a 1-5 mu m camera (called LMIRCam), and an 8-13 mu m camera (called NOMIC). The key program for LBTI is the Hunt for Observable Signatures of Terrestrial planetary Systems (HOSTS), a survey using nulling interferometry to constrain the typical brightness from exozodiacal dust around nearby stars. Additional observations focus on the detection and characterization of giant planets in the thermal infrared, high spatial resolution imaging of complex scenes such as Jupiter's moon, Io, planets forming in transition disks, and the structure of active Galactic Nuclei (AGN). Several instrumental upgrades are currently underway to improve and expand the capabilities of LBTI. These include: Improving the performance and limiting magnitude of the parallel adaptive optics systems; quadrupling the field of view of LMIRcam (increasing to 20"x20"); adding an integral field spectrometry mode; and implementing a new algorithm for path length correction that accounts for dispersion due to atmospheric water vapor. We present the current architecture and performance of LBTI, as well as an overview of the upgrades.
2

Infrared photometry with 'wall-eyed' pointing at the Large Binocular Telescope

Spalding, Eckhart, Skemer, Andrew, Hinz, Philip M., Hill, John M. 09 August 2016 (has links)
The brightness and variability of the atmosphere in the thermal infrared poses obstacles to precision photometry measurements. The need to remove atmospheric effects calls for the use of a comparison star, but it is usually impossible to fit both science and comparison targets on current long-wavelength (> 2 mu m) detectors. We present a new pointing mode at the Large Binocular Telescope, which has twin 8.4-m primary mirrors that can be pointed up to similar to 2 arcminutes apart and allow the placement of both targets on a small-field infrared detector. We present an observation of the primary transit of an exoplanet in front of its host star, and use it to provide preliminary constraints on the attainable photometric precision.
3

Simultaneous water vapor and dry air optical path length measurements and compensation with the large binocular telescope interferometer

Defrère, D., Hinz, P., Downey, E., Böhm, M., Danchi, W. C., Durney, O., Ertel, S., Hill, J. M., Hoffmann, W. F., Mennesson, B., Millan-Gabet, R., Montoya, M., Pott, J.-U., Skemer, A., Spalding, E., Stone, J., Vaz, A. 04 August 2016 (has links)
The Large Binocular Telescope Interferometer uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 microns). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI/MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current performance of the system for dry air seeing compensation, we present simultaneous H-, K-, and N-band observations that illustrate the feasibility of our feedforward approach to stabilize the path length fluctuations seen by the LBTI nuller.
4

Taking Measure of the Menagerie: Observational Constraints on Supernovae and Their Progenitors

Vallely, Patrick John 06 September 2022 (has links)
No description available.
5

Learning-Based Testing of Microservices : An Exploratory Case Study Using LBTest / Inlärningsbaserad testning av microservices

Nycander, Peter January 2015 (has links)
Learning-based testing (LBT) is a relatively new testing paradigm which automatically generates test cases for black-box testing of a system under test (SUT). LBT uses machine learning to model a SUT, and combines this with model-based testing. This thesis uses LBTest, a research tool created at CSC, in order to apply LBT on a new architectural style of distributed systems called microservices. Two new approaches to using LBT have been implemented to test a commercial product for counter-party credit risk. One approach is to monitor the internal processes to extract the states of the software. The second is based on fault injection on the software level. Errors have been found during the fault injection approach. Lastly, some general recommendations are given on how to implement LBT. / Inlärningsbaserad testning (LBT) är en relativt ny testningsparadigm som automatiskt genererar testfall för black-box-testning av ett system under test (SUT). LBT använder sig av maskininlärning för att modellera ett SUT, och kombinerar det med modellbaserad testning. I det här examensarbetet används LBTest, ett forskningverktyg skapat på CSC, för att applicera LBT på microservices. Två nya tillvägagångssätt att använda LBT på har implementerats för att testa en kommersiell produkt för uträkning av kreditrisk hos motparter. Ett tillvägagångssätt är att avlyssna interna processer för att extrahera tillstånden hos mjukvaran. Det andra tillvägagångssättet är baserat på felinjicering på mjukvarunivå. Fel har hittats med hjälp av felinjiceringstillvägagångssättet. Som avslutning ges rekommendationer till hur LBT implementeras.
6

Lambda Bipolar Transistor (LBT) in Static Random Access Memory Cell

Sarkar, Manju 06 1900 (has links)
With a view to reduce the number of components in a Static Random Access Memory (SRAM) cell, the feasibility of use of Lambda Bipolar Transistor (LBT)in the bistable element of the cell has been explored under the present study. The LBT under consideration here comprises of an enhancement mode MOSFET integrated with a parasitic bipolar transistor so as to perform as a negative resistance device. LBTs for the study have been fabricated and analysed. The devices have been shown to function at much lower voltage and current levels than those reported earlier/ and thus have been shown to be suitable for lower power applications. The issues of agreements and discrepancies of the experimental results with the original DC model of the device have been highlighted and discussed. The factors contributing to the drain current of the MOSFET in the LBT have been identified. It has also been shown that in the real case of an LBT in operation, the MOSFET in it does not function as a discrete device for the same conditions of voltages and current levels as in an LBT. As per the present study, it is assessed to be influenced by the presence of the BJT in operation and this effect is felt more at the lower current levels of operation. With a separate and tailored p-well implantation the possibility of fabrication of LBTs with a CMOS technology is established. Along with a couple of polysilicon resistors, the LBTs have been successfully made to perform in the common-collector configuration as the bistable storage element of SRAM cell (as proposed in the literature). The bistable element with the LBT in common-emitter mode also has been visualised and practically achieved with the fabricated devices. The WRITE transients for either case have been simulated for various levels of WRITE voltages and their time of hold.The speed of Writing achieved are found comparable with that of the standard SRAMs. The advantages and disadvantages of using the LBT in either mode have been highlighted and discussed. The power consumption of the bistable element with the LBT in either mode is however shown to be the same. A different approach of READING has been proposed to overcome the factors known to increase the cycle time. On the whole, under the present study, the proposal of using LBTs in the bistable storage element of the SRAM cell has been shown to be feasible. Such SRAM circuits can find possible applications in the fields where smaller circuit area is the major concern.
7

Solu??es de coexist?ncia LTE/Wi-Fi em banda n?o licenciada

Santana, Pedro Maia de 07 December 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-04-02T12:36:23Z No. of bitstreams: 1 PedroMaiaDeSantana_DISSERT.pdf: 2069422 bytes, checksum: 1a983f5131609d3cf7fe3bd96b0ef27d (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-04-04T13:34:35Z (GMT) No. of bitstreams: 1 PedroMaiaDeSantana_DISSERT.pdf: 2069422 bytes, checksum: 1a983f5131609d3cf7fe3bd96b0ef27d (MD5) / Made available in DSpace on 2018-04-04T13:34:36Z (GMT). No. of bitstreams: 1 PedroMaiaDeSantana_DISSERT.pdf: 2069422 bytes, checksum: 1a983f5131609d3cf7fe3bd96b0ef27d (MD5) Previous issue date: 2017-12-07 / Este trabalho tem como objetivo realizar um estudo sobre a aplica??o de redes LTE no espectro ISM (Industrial Scientific and Medical) e seu consequente impacto sobre tecnologias comumente coexistentes na mesma faixa de frequ?ncia. Inicialmente, ? realizada uma elucida??o te?rica sobre as regulamenta??es que envolvem o uso de espectro n?o-licenciado. Na sequ?ncia, s?o apresentadas as principais solu??es de coexist?ncia do LTE nesse meio, destacando-se o mecanismo recentemente padronizado pelo 3GPP, o LTE-LBT, e tecnologias espec?ficas de empresas pioneiras na ?rea, tais como a solu??o LTE-DC. Como elemento pr?tico complementar ? investiga??o te?rica inicial, s?o desenvolvidas an?lises de desempenho das respectivas solu??es utilizando o simulador ns-3. A novidade do trabalho ? materializada pela apresenta??o de uma proposta de solu??o para o mecanismo Carrier-Sensing Adaptive Transmission (CSAT). Essa solu??o, baseada em aprendizado de m?quina, visa melhorar o desempenho conjunto dos sistemas que coexistem na faixa ISM. Este trabalho tamb?m prop?e uma solu??o de coexist?ncia do LTE-DC consigo pr?prio a partir de uma abordagem utilizando teoria dos jogos. Essas solu??es s?o comparada com as solu??es cl?ssicas e o seus ganhos s?o evidenciado em cen?rios definidos por ?rg?os de padroniza??o mundial. / This work aims to perform a study about the application of LTE networks in ISM (Industrial Scientific and Medical) spectrum and its impact over technologies that communly coexist in the same frequency range. Initially, it?s made a theoretical elucidation about regulamentations involving the non licensed spectrum usage. In sequence, it?s presented the main LTE coexistence solutions in this field, highlighting the recent mechanism standardized by 3GPP, the LTE-LBT, and specific technologies of pioneering companies in this domain, like LTE-DC solution. As a practical element complementary to the initial theoretical investigation, it?s developed performance analyzes of the respective solutions using ns-3 simulator. The novelty of the work is materialized by the presentation of a solution proposal for the Carrier-Sensing Adaptive Transmission (CSAT). This solution, based on machine learning, aims to improve the joint performance of systems that coexist in the ISM band. This work also propose a solution for LTE-DC self-coexistence by a game theory approach. These solutions are compared to the classical ones and their gains are evidenced in scenarios defined by global standardization institutions.
8

"Lager utav oro" : Erfarenheter och farhågor kring graviditet och förlossning, hos förlossningsrädda lesbiska och bisexuella kvinnor och transpersoner / "Layers of worry" : Experiences and fears of pregnancy and childbirth in lesbian and bisexual women and transgender people with fear of childbirth

Jonsson, Louise, Wikström, Johanna January 2018 (has links)
Förlossningsrädsla har tidigare främst undersökts hos kvinnor som lever i heterosexuella relationer, och på senare tid även kommit att inkludera deras manliga partners upplevelser av rädsla. Förlossningsrädsla kan påverka negativt under familjebildningen, vilket gör den viktig att uppmärksamma i alla familjekonstellationer. Syftet med denna studie var att undersöka hur förlossningsrädsla erfars och tar sig uttryck hos lesbiska/bisexuella kvinnor och transpersoner, samt vad olika typer av bemötande i vården får för betydelse för dem och deras rädsla. Data samlades in genom semistrukturerade intervjuer med tio deltagare. De transkriberade intervjuerna bearbetades genom tematisk analys med en induktiv ansats.  Analysen resulterade i fem huvudteman som handlar om förlossningsrädslan, omkringliggande aspekter och hur bemötande i vården påverkar rädslan; Mina förlossningsrädslor, Naturlighet, cisnormer och femininitet, Vägen till barn, Att vara sårbar och utsatt under en förlossning och Bemötande i vården. Resultatet visar på att deltagarnas förlossningsrädsla är lik den som rapporterats i forskning i stort, men att det delvis tillkommer vissa nya aspekter för denna grupp. Förlossningsrädslan influeras av deras erfarenheter av bemötande i vården och den större omgivande sociala kontexten som påverkar genom processer av normer, minoritetsstress, hetero- och cisnormativitet och diskriminering. För vissa deltagare har förlossningsrädslan dessutom påverkats av att ha deltagit vid en partners förlossning. / Förlossningsrädsla hos lesbiska/bisexuella kvinnor och transpersoner - Förekomst, upplevelser och erfarenheter
9

Measuring the Technical and Process Benefits of Test Automation based on Machine Learning in an Embedded Device / Undersökning av teknik- och processorienterade fördelar med testautomation baserad på maskininlärning i ett inbyggt system

Olsson, Jakob January 2018 (has links)
Learning-based testing is a testing paradigm that combines model-based testing with machine learning algorithms to automate the modeling of the SUT, test case generation, test case execution and verdict construction. A tool that implements LBT been developed at the CSC school at KTH called LBTest. LBTest utilizes machine learning algorithms with off-the-shelf equivalence- and model-checkers, and the modeling of user requirements by propositional linear temporal logic. In this study, it is be investigated whether LBT may be suitable for testing a micro bus architecture within an embedded telecommunication device. Furthermore ideas to further automate the testing process by designing a data model to automate user requirement generation are explored. / Inlärningsbaserad testning är en testningsparadigm som kombinerar model-baserad testning med maskininlärningsalgoritmer för att automatisera systemmodellering, testfallsgenering, exekvering av tester och utfallsbedömning. Ett verktyg som är byggt på LBT är LBTest, utvecklat på CSC skolan på KTH. LBTest nyttjar maskininlärningsalgoritmer med färdiga ekvivalent- och model-checkers, och modellerar användarkrav med linjär temporal logik. I denna studie undersöks det om det är lämpat att använda LBT för att testa en mikrobus arkitektur inom inbyggda telekommunikationsenheter. Utöver det undersöks även hur testprocessen skulle kunna ytterligare automatiseras med hjälp av en data modell för att automatisera generering av användarkrav.

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