Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 121-123). Also available via the Internet.

O problema desta pesquisa se configura em analisar as variáveis envolvidas no aprendizado da resposta de observação visual apropriada em arranjos com diferentes variações de estímulos irrelevantes e as implicações deste aprendizado para o estabelecimento da discriminação. O aprendizado da resposta de observação apropriada não vem apenas expor o animal aos estímulos especificados, no sentido de que o animal passa a atentar a eles, mas envolve o aprendizado sobre a relevância desses estímulos e, simultaneamente faz com que o animal deixe de atentar e a responder aos estímulos irrelevantes. No que se refere ao estabelecimento da discriminação, este problema de pesquisa foi tratado prioritariamente no período pressolução. Ampla extensão do período pressolução ou mesmo falhas no estabelecimento da discriminação podem ser determinadas por falhas no aprendizado sobre a relevância dos estímulos discriminativos. Nesse sentido, o procedimento proposto objetiva analisar o papel dos estímulos irrelevantes sobre a distribuição das respostas de observação e o aprendizado daquela que foi definida como apropriada em função dos estímulos discriminativos. A análise foi realizada em tarefas de discriminação simultânea com diferentes variações de pares de estímulos irrelevantes. Estas variações foram apresentadas para quatro grupos de oito participantes cada. Estas variações foram apresentadas na seguinte ordem: Constante (Grupo Const) Inter-tentativas (Grupo Inter) Intra-tentativas (Grupo Intra) Variações combinadas (Grupo Comb). Os resultados mostraram que a extensão do período pressolução para os Grupos Intra e Comb foi maior do que para os Grupos Const e Inter. Inversamente, a distribuição da observação para os estímulos discriminativos foi menor para os Grupos Intra e Comb em comparação aos demais grupos nas três primeiras tentativas. Algumas questões foram fundamentais para a análise e a discussão sobre o aprendizado da resposta de observação apropriada a partir de diferentes arranjos de estímulos e em função das consequências diferenciais. Entre elas, o papel mediador da última observação entre as diferentes consequências e a variação e modelagem das respostas de observação. Discutiu-se que houve situações onde o aprendizado sobre a irrelevância dos estímulos bem como situações onde o aprendizado sobre a relevância dos estímulos foi requerido. O requerimento deste aprendizado afetou o aprendizado da resposta de observação apropriada / The problem of this research is to analyze the variables involved in appropriate visual observing learning in arrangements with different variations of irrelevant stimuli and its implications for the discrimination establishment. The learning of the observing response comes not only expose the animal to discriminative stimuli in the sense that the animal begins to pay attention to them, but involves learning about the relevance of these stimuli. Simultaneously the animal ignores the irrelevant stimuli. Wide extension of the pre-solution period can be determined by failures in learning about the relevance of the discriminative stimuli. In this sense, the procedure aims to analyze the role of irrelevant stimuli on the distribution of observing responses. The analysis was performed in simultaneous discrimination tasks with different variations of irrelevant stimuli. These variations were made for four groups of each eight participants. These variations were presented in the following order: Constant (Group Const) - Inter-trials (Group Inter) - Intra-trials (Group Intra) combined variations (Group Comb). The results showed that the extent of pre-solution period for Intra and Comb groups was greater than for Const and Inter Groups. Conversely, the distribution of the observation to the discriminative stimuli was smaller for Intra and Comb groups compared to the other groups in the first three trials. Some issues were central in order to analyze the appropriated observing learning for example the role of last observing and the different consequences. There were situations where learning about the irrelevance was required. Learning about the irrelevance affected the appropriate observing response learning

Este trabalho apresenta o projeto de uma portadora que opera na frequência de 8.300 MHz para ser utilizado em moduladores vetoriais diretos com aplicação em sistemas embarcados de satélites. Foram realizados estudos sistêmicos de arquiteturas que operam nesta faixa de frequência com as características necessárias para atender as especificações da European Cooperation for Space Standardization, ECSS - Space Engineering Radio Frequency and Modulation da agência espacial europeia -ESA, que regulamenta as frequências e características para sistemas de transmissão para enlace de descida. A partir dos conhecimentos adquiridos nos estudos, é apresentada uma metodologia de projeto visando o atendimento das especificações definidas pela ECSS e a escolha de uma topologia de projeto. Foram realizadas simulações a nível sistêmico, utilizando o software Advanced Design System-ADS da fabricante Keysight Technologies, para definir as especificações de projeto dos circuitos que compõem o sistema de geração da portadora na banda X. O circuito da malha de sincronismo de fase - PLL opera na frequência de 2.075 MHz, onde seu sinal é amplificado e filtrado pela cadeia de amplificação na banda S cuja função é aumentar a isolação para minimizar os efeitos de pulling do oscilador controlado por tensão - VCO, devido à alta velocidade nas transições de tempo de subida e de descida dos sinais digitais I e Q. O filtro também é responsável por aumentar a rejeição de espúrios e harmônicos gerados pelos efeitos não lineares dos amplificadores. O sinal é enviado ao circuito multiplicador de frequências que gera o sinal na banda X e é filtrado por um filtro passa-faixas de linhas acopladas, rejeitando os sinais espúrios provenientes da saída do multiplicador de frequência. Na saída, o sinal passa por uma cadeia de amplificação na banda X para adequar o nível de potência à entrada dos moduladores vetoriais. Os circuitos projetados foram desenvolvidos utilizando tecnologia de microfita de linha. Os protótipos foram caracterizados, apresentando boa concordância com os resultados simulados, comprovando experimentalmente a metodologia de projeto utilizada neste trabalho assim como o atendimento das especificações sugeridas pela ECSS. / This work presents the project of an carrier that works in the frequency of 8,300 MHz to be used in direct vector modulator for embedded system application in satellites. It were realized system level studies of PLL topologies that work in this frequency range with the necessary features to provide the requirements from European Cooperation for Space Standardization, ECSS - Space Engineering Radio Frequency and Modulation of the European Space Agency - ESA, which is responsible for the frequencies and features regulation for downlink transmission system. With the knowledge acquired from the studies, it is presented a project method intending to the meet the requirements defined by the ECSS and the definition of a topology to the project. It were performed system level simulation, using the Advanced Design System - ADS tool, from Keysight Technologies, in order to define the design specifications in the project of the circuits of the X band carrier generator developed. The PLL circuit works in the frequency of 2,075 MHz, in which its signal is amplified and filtered for amplifier chain in S band, increasing the isolation to reduce the pulling effects in the voltage controlled oscillator, due to the high-speed transitions in the rise time and fall time of the digital signal I and Q. The filter is also responsible for increasing the rejection of spurious and harmonics generated by non-linear amplifiers effects. The signal is conducted to the frequency multiplier circuit that generates the X band signal and it is filtered by a coupled line bandpass filter, rejecting the spurious from the frequency multiplier output. At the output stage, the signal passes through a X band amplification chain in order to adequate the power level of the vector modulators input level. The specified circuits were designed and developed using microstrip line technology. The prototypes were characterized, presenting adequate results according to the data obtained by the simulations, experimentally reinforcing the project method used in this work as well as the meeting of the requirements suggested by the ECSS.

We report photometric measurements of a sodium resonance guide star against the daylight sky when observed through a tuned magneto-optical filter (MOF). The MOF comprises a sodium vapor cell in a kilogauss-level magnetic field between crossed polarizers and has a very narrow transmission profile at the sodium D-2 resonance of approximately 0.008 nm. Our observations were made with the 1.5 m Kuiper telescope on Mt. Bigelow, AZ, which has a separately mounted guide star laser projecting a circularly polarized single-frequency beam of approximately 6.5 W at 589.16 nm. Both the beam projector and the 1.5 m telescope were pointed close to zenith; the baseline between them is approximately 5 m. Measurements of the guide star were made on the morning of 2016 March 24 using an imaging camera focused on the beacon and looking through the full aperture of the telescope. The guide star flux was estimated at 1.20x10(6) photon/m(2)/s while at approximately 45 minutes after sunrise, the sky background through the MOF was 1100 photon/m(2)/s/arcsec(2). We interpret our results in terms of thermal infrared observations with adaptive optics on the next generation of extremely large telescopes now being built.

The thesis will consider ways of understanding drawing as an endless process, an experience leading to an intensification and understanding of the world, myself and capabilities of mine. Creation of long-term portrait studies, as a constant reiteration and improvement of the drawing. The theoretical part of the work defines the historical use of drawing as a material and tool for daily rituals in the visual arts, with an emphasis on artists of the 19th and 20th centuries. In the practical part, a series of portrait drawings was made in various techniques, which is listed in the theoretical part. In the didactic part, an artistic cycle on the theme "Endless drawing" / drawing as knowledge of the world was realized. KEYWORDS Drawing, portrait , self-portrait, face, graphics, artistic image, collage

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No description available.

Spotify is a music streaming service that allows users to listen to their favourite music. Due to the rapid growth in the number of users, the amount of processing that must be provided by the company’s data centers is also growing. This growth in the data centers is necessary, despite the fact that much of the music content is actually sourced by other users based on a peer-to-peer model. Spotify’s backend (the infrastructure that Spotify operates to provide their music streaming service) consists of a number of different services, such as track search, storage, and others. As this infrastructure grows, some service may behave not as expected. Therefore it is important not only for Spotify’s operations (footnote: Also known as the Service Reliability Engineers Team (SRE)) team, but also for developers, to understand exactly how the various services are actually communicating. The problem is challenging because of the scale of the backend network and its rate of growth. In addition, the company aims to grow and expects to expand both the number of users and the amount of content that is available. A steadily increasing feature-set and support of additional platforms adds to the complexity. Another major challenge is to create tools which are useful to the operations team by providing information in a readily comprehensible way and hopefully integrating these tools into their daily routine. The ultimate goal is to design, develop, implement, and evaluate a tool which would help the operations team (and developers) to understand the behavior of the services that are deployed on Spotify’s backend network. The most critical information is to alert the operations staff when services are not operating as expected. Because different services are deployed on different servers the communication between these services is reflected in the network communication between these servers. In order to understand how the services are behaving when there are potentially many thousands of servers we will look for the patterns in the topology of this communication, rather than looking at the individual servers. This thesis describes the tools that successfully extract these patterns in the topology and compares them to the expected behavior. / Spotify är en växande musikströmningstjänst som möjliggör för dess användare att lyssna på sin favoritmusik. Med ett snabbt växande användartal, följer en tillväxt i kapacitet som måste tillhandahållas genom deras datacenter. Denna växande kapacitet är nödvändig trots det faktum att mycket av deras innehåll hämtas från andra användare via en peer-to-peer modell. Spotifys backend (den infrastruktur som kör Spotifys tjänster) består av ett antal distinkta typer som tillhandahåller bl.a. sökning och lagring. I takt med att deras backend växer, ökar risken att tjänster missköter sig. Därför är det inte bara viktigt för Spotifys driftgrupp, utan även för deras utvecklare, att förstå hur dessa kommunicerar. Detta problem är en utmaning p.g.a. deras storskaliga infrastruktur, och blir större i takt med att den växer. Företaget strävar efter tillväxt och förväntar detta i både antalet användare och tillgängligt innehåll. Stadigt ökande funktioner och antalet distinkta plattformar bidrar till komplexitet. Ytterligare en utmaning är att bidra med verktyg som kan användas av driftgrupp för att tillhandahålla information i ett tillgängligt och överskådligt format, och att förhoppningsvis integrera dessa i en daglig arbetsrutin. Det slutgiltiga målet är att designa, utveckla, implementera och utvärdera ett verktyg som låter deras driftgrupp (och utvecklare) förstå beteenden i olika tjänster som finns i Spotifys infrastruktur. Då dessa tjänster är utplacerade på olika servrar, reflekteras kommunikationen mellan dem i deras nätverketskommunikation. För att förstå tjänsternas beteende när det potentiellt kan finnas tusentals servrar bör vi leta efter mönster i topologin, istället för beteenden på individuella servrar.

Attentional biases occur with various psychological disorders, including drugaddiction and anxiety. Conditioned reinforcement likely plays a role in maintainingattentional biases to stimuli associated with reinforcement for unwanted behavior. Theobserving-response procedure is considered a model of attending as reflected byresponding maintained by conditioned reinforcement. Effects of primary reinforcement on the persistence of observing have been studied in the framework of behavioral momentum theory. Studies have shown observing-responses to be more resistant tochange in contexts arranging relatively higher rates of primary reinforcement. Recently, behavioral momentum theory has been extended to describe the effects of primary reinforcement context in relapse phenomena. The present thesis aimed to extend research on the resistance to change of observing to animal models of relapse. Pigeons responded on a two-component multiple schedule of observing-response procedures. In a rich component, observing responses produced stimuli correlated with a high rate of variableinterval (VI) food reinforcement (Rich S+). In a lean component, observing responses produced stimuli correlated with a low rate of VI food reinforcement (Lean S+). Following stable performance, responding was extinguished by removing food and S+ presentations. After extinction, relapse was assessed by reinstatement tests consisting of response-independent presentations of food or S+. Replicating earlier results, observingand food-key responding was more resistant to extinction in the Rich component. Food reinstatement had no systematic effect on extinguished food- and observing-key responding. However, S+ reinstatement resulted in relapse of extinguished observingand food-key responding. Relapse during S+ reinstatement was greater in the Rich component than the Lean component. Reinstatement of responding by S+ presentations resulted in a greater overall increase in responding on the food-key relative to the observing-key. This result suggests that an important functional relationship between the presence of S+ stimuli and increased rates of primary reinforcement for food key responding remained intact during extinction. The results show that observing is susceptible to relapse, and the magnitude of relapse depends on baseline primary reinforcement rate in a context.

The law of small numbers bias is a representativeness heuristic that often leads individuals to draw extensive conclusions from small samples while underestimating the generalizability in larger ones. This study investigated whether individuals overestimate perceived discrimination in small employment samples and underestimate it in large ones. A pre-registered scenario-based experiment was conducted, where participants (N = 874) estimated probability of discrimination versus chance in skewed hiring distributions. We manipulated employment sample size (filling four vs. 100 positions) and ethnic majority (hiring more immigrants or Swedes) using a 2x2 between-subject design. A tendency for people to overestimate perceived discrimination by underestimating the impact of chance in small employment samples was revealed. Conversely, in large employment samples, people tended to underestimate perceived discrimination by overestimating the impact of chance. Hence, results aligned with the law of small numbers. Furthermore, participants were more inclined to attribute an event as discriminatory when organizations hired more Swedes than immigrants, reflecting (accurate) prototypes of discrimination. This study's implications are discussed concerning the repercussions of underestimating and overestimating perceived discrimination in hiring situations. Future research suggestions are also provided.