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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

Mental imagery in link system / La imagen mental en el sistema de enlace

Campos García, Alfredo, Fernández, Clara Isabel 25 September 2017 (has links)
Four experiments were carried out to explore the intluence of imaging capacity and image type (normal or bizarre) on immediate and delayed recall of word lists. Experiments 1 and 2 studied immediate serial recall of 16- and 28-item word lists, and experiments 3 and 4 studied serial recall of 16- and 28- item word lists one week after their presentation. Imaging capacity, as measured by the Space Scale of the Primary Mental Abilities Test, affected immediate recall of long lists. Image type affected immediate recall of short lists. In four experiments there was a significant difference between the performance of subjects who used mental imagery for recall and those who did not. / El  artículo estudia a través de cuatro experimentos la influencia de la capacidad de los sujetos para formar imágenes y del tipo de imagen que utilizan, en el recuerdo serial inmediato y retardo de palabras. En los experimentos 1 y 2 se analiza la influencia de estas variables en el recuerdo serial inmediato de listas cortas (16 ítems) y largas (28 ítems), y en los experimentos 3 y 4 se investiga la influencia de las mismas variables en el recuerdo serial retardado (una semana). La capacidad de los sujetos de formar imágenes, medida a través de la Escala Espacial del Test de Aptitudes Mentales Primarías, influyó en el recuerdo serial inmediato de listas largas. El tipo ele imagen (normal y rara) influyó en el recuerdo inmediato serial de listas cortas. En todos los experimentos se encontró diferencia entre los sujetos que utilizaron imágenes mentales y los que no las utilizaron.
2

"Don't Leave the Pad Without It": Using Deployable Assets to Conduct Pre-Launch and On-Orbit Testing

Morimoto, Todd, Sargent, Cliff 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / When hundreds of millions of dollars are invested in building, launching, and command/control of modern military space systems, the developers and operators need assurance that when their system achieves orbit, it will be able to "talk" with the ground network, exchanging commands, telemetry and ranging signals. Furthermore, prior to launch they need proof of compatibility with the ground data systems, showing that operational ground-based crypto keys, database parameters, and processing software are in-fact compatible with the spacecraft. This paper describes Air Force Materiel Command (AFMC), Space & Missile Center (SMC) Detachment 2's four classes of deployable test assets, emphasizing deployable's contribution to successful on-orbit performance. With not only the huge dollar investment, but even more important, the ability to execute a vital test or operational mission riding on compatibility, and launch vehicle and on-orbit test and evaluation operations the watchwords are "Don't leave the pad without it."
3

Physical modeling of optical modulators for optical link analysis : Optical link analysis in silicon photonics technologies

Poggi, Daniele January 2019 (has links)
According to the 2018 Ethernet Roadmap projections, the requirements for high speed links keep increasing every year, always keeping an eye on the energy per bit consumption of the communication system. The Ethernet requirements are estimated to reach 1Tbps by 2022-2025. Optical links are one of the most concrete solutions to satisfy bandwidth requirements at low energy consumption. An optical link is a communication system that consists of a single end-to-end optical circuit. In contrast with vertical-cavity surface-emitting laser (VCSEL) technology, which is based on a direct laser modulation, silicon photonics technology (SPT) is based on indirect modulation. In order to perform the modulation, electro-optical modulators are needed in the optical link system for electrically modulating the optical power.This master thesis, developed at imec, will present the modeling of two different technologies of optical modulators: Silicon Ring Modulator and the Franz-Keldysh ElectroAbsorption Modulator. The work was initiated, since there were no available models of these devices in the actual framework for link analysis. First a preliminary study of the physical principles of the two devices was performed, in order to build the Matlab models. Then, these models were fitted with measurements, in order to adjust them to real-life behavior. After having obtained two working models of the two modulators, an alreadyexisting framework was used, to compare the energy consumption per bit in the optical link. However, the results obtained with the simulation didn’t highlight a technology to be preferred to the other. / Enligt prognoserna från Ethernet Roadmap 2018 fortsätter kraven på höghastighetslänkar att öka varje år och håller alltid ett öga på kommunikationssystemets energi konsumtion per bit. Ethernet-kraven beräknas nå 1Tbps 2022-2025.Optiska länkar är en av de mest konkreta lösningarna för att tillgodose bandbreddskrav vid låg energiförbrukning. En optisk länk är ett kommunikationssystem som utgör en punkt till punkt förbunden optisk krets. I motsats till teknik som utnyttjar den vertikala kavitetsytemitterande lasern (VCSEL), som bygger på en direkt lasermodulering, baseras kisel fotonikteknik (SPT) på indirekt modulering. För att utföra en modulering behövs elektrooptiska modulatorer i det optiska länksystemet för att elektriskt modulera den optiska effekten.Denna masteruppsats, utvecklad vid imec, kommer att presentera modelleringen av två olika teknologier av optiska modulatorer: Silicon Ring Modulatorn och Franz-Keldysh Electro Absorption Modulator. Arbetet, genomfördes eftersom det inte fanns några tillgängliga modeller av dessa enheter i själva ramverket för länkanalys. För det första genomfördes en preliminär studie av de två enheternas fysikaliska principer för att bygga Matlab-modellerna. Sedan jämfördes dessa modeller med mätningar för att anpassa dem till verkligt beteende. Efter att ha fått två arbetsmodeller av de två modulatorerna användes ett redan existerande ramverk för att jämföra energikonsumtionen per bit i den optiska länken. De resultat som erhölls med simuleringen indikerade emellertid inte någon teknik som skulle föredras framför den andra.

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