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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.
11

Recalibração de um modelo para simulação do tráfego em rodovias de pista simples / Recalibration of a traffic simulation model for two-lane highways

Cintia Yumiko Egami 19 December 2000 (has links)
O objetivo desta pesquisa foi recalibrar um modelo de simulação de rodovias de pista simples a fim de seja possível usá-lo no estudo de estradas do Estado de São Paulo. O modelo escolhido para recalibração é o TRARR (TRAffic on Rural Roads) versão 4.0, desenvolvido na Austrália pelo ARRB Transport Research Ltd. A recalibração do modelo consistiu em alterar parâmetros referentes ao desempenho (relação potência/massa) e características (massa, comprimento) dos veículos pesados e um parâmetro relativo ao comportamento dos veículos quando viajando em pelotões, de tal modo que os resultados da simulação ficassem compatíveis com os observados em campo. As medidas de desempenho escolhidas para a recalibração foram: a porcentagem de veículos trafegando em pelotões, a velocidade média dos veículos e a taxa de ultrapassagens. Os dados para a recalibração do modelo foram coletados num trecho de 2,8 km de extensão, na rodovia SP 255, entre as cidades paulistas de Araraquara e Ribeirão Preto. No processo de recalibração, as medidas de desempenho observadas no campo foram comparadas com as produzidas pelas versões recalibrada e original do simulador. Ao final da recalibração, pôde-se concluir que as duas versões do modelo são capazes de simular adequadamente o trecho estudado, sendo que o modelo recalibrado produz resultados ligeiramente melhores que os da versão original. O modelo recalibrado foi validado simulando-se um trecho de 10 km de extensão da SP 255 e comparando-se os valores medidos no trecho para as medidas de desempenho escolhidas com os valores produzidos pela versão recalibrada do simulador. Os resultados dessa comparação indicam que o modelo pode ser considerado capaz de simular adequadamente a operação de rodovias de pista simples no Estado de São Paulo. Os resultados do estudo também sugerem que a precisão pode ser melhorada com um ajuste fino de alguns dos parâmetros não modificados durante a recalibração. / The objective of this research is to recalibrate a two-lane highway simulation model to allow its employment within the context of the São Paulo state highways, Brazil. The model chosen for this recalibration is TRARR (TRAffic on Rural Roads) version 4.0, originally developed a in Australia by ARRB Transport Research Ltd. The procedure used for the model recalibration consisted in modifying input parameters related to heavy vehicle dimensions and performance characteristics (power/mass ratio, weight and length) as well as to the behavior of vehicles in platoons, in such a way that the model outputs are compatible with real traffic behavior. Three measures of performance were chosen for recalibration of the model: percent of jouney time spent following, average speed and overtaking rate. Data for model recalibration were collected at a 2.8 km rural section of SP 225, a highway which connects the cities of Ribeirão Preto and Araraquara in the state of São Paulo (Brazil). The recalibration procedure was based on comparisons of the measures of performance observed on the real highway with those produced by the simulator\'s recalibrated and original versions. At the end of the recalibration process, both the recalibrated and the original models were considered capable of reproducing the traffic behavior on a two-lane highway similar to the ones in the state of São Paulo. Furthermore, it was concluded that the recalibrated model is capable of producing results slightly better than the original one. The recalibrated model was submitted to a validation procedure in which a 10 km section of SP 255 was simulated and the measures of perfomance obtained with the model were compared to field observations. The results of the validation procedure indicate that recalibrated version of TRARR is capable of simulating traffic operations on rural two-lane highways in the state of São Paulo. The results of the research also suggest that the model results may be improved with fine-tuning of some of the parameters that were not modified during the recalibration procedure.
12

The online regulation of no-vision walking in typically calibrated and recalibrated perceptual-motor states examined using a continuous pointing task

Burkitt, James January 2017 (has links)
No-vision walking is supported in the central nervous system (CNS) by a spatial updating process. This process involves the iterative updating of a mental representation of the environment using estimates of distance traveled gleaned from locomotive kinematic activity. An effective means of examining the online regulation of this process is a continuous pointing task, which requires performers to walk along a straight-line forward trajectory while keeping their right arm straight and index finger fixated on a stationary ground-level target beside the walking path. In the current thesis, no-vision continuous pointing was examined in typically calibrated and recalibrated perceptual-motor states. Shoulder and trunk joint angles provided the basis for perceptual measures that reflected spatial updating performance and kinematic measures that reflected its underlying CNS online regulation. In the typically calibrated conditions, no-vision walking demonstrated a slight perceptual underestimation of distance traveled (Study 1). In the recalibrated conditions, no-vision walking demonstrated: a) perceptual underestimation and overestimation following adaptation periods involving walking with low and high visual gains, respectively (Study 2); and b) partial recalibration following exposures to vision and arm gains (Study 3). The latter was suggested as being impacted by task specific changes in CNS multisensory integration resulting from the development of a robust task prior and/or the altering of sensory cue weights. Importantly, this thesis used a novel trajectory parsing procedure to quantify discrete CNS perceptual updating units in the shoulder plane of elevation trajectory. The starts and ends of these updating units were consistently timed to the late left-to-early right foot swing phase of the step-cycle, regardless of perceptual-motor state. This was suggested to reflect perceptual units that were purposely timed, but indirectly mapped, to this kinematic event. The perceptual differences in Studies 1 and 2 were at least partially reflected in these units. / Thesis / Doctor of Philosophy (PhD) / It is well understood that humans can effectively walk without vision to environmental locations up to 15 metres away. However, less is known about how these walking movements are controlled during the course of forward progression. This thesis fills this knowledge gap using a task that requires participants to walk forward along a straight path while keeping their right index finger pointed toward a ground-level target beside the walking path. The patterns of arm movements performed during this task are indicative of the control strategies used by the performer to mentally update their positions in space. One of the key contributions of this work is showing that humans perform this mental updating in a repetitive manner, and that these repetitions are consistently linked to early forward movements of the right leg. This pattern is maintained when walking without vision is performed in a variety of different contexts.
13

Effect before cause: supramodal recalibration of sensorimotor timing

Heron, James, Hanson, James Vincent Michael, Whitaker, David J. January 2009 (has links)
Yes / Our motor actions normally generate sensory events, but how do we know which events were self generated and which have external causes? Here we use temporal adaptation to investigate the processing stage and generality of our sensorimotor timing estimates. Methodology/Principal Findings: Adaptation to artificially-induced delays between action and event can produce a startling percept¿upon removal of the delay it feels as if the sensory event precedes its causative action. This temporal recalibration of action and event occurs in a quantitatively similar manner across the sensory modalities. Critically, it is robust to the replacement of one sense during the adaptation phase with another sense during the test judgment. Conclusions/Significance: Our findings suggest a high-level, supramodal recalibration mechanism. The effects are well described by a simple model which attempts to preserve the expected synchrony between action and event, but only when causality indicates it is reasonable to do so. We further demonstrate that this model successfully characterises related adaptation data from outside the sensorimotor domain.
14

Implementation and Evaluation of the Decentralized Fund Protocol : Creating a decentralized asset management system / Implementation och utvärdering av Decentralized Fund Protocol : utformning av ett decentraliserat tillgångsförvaltningssystem

Svanholm, Fredrik January 2024 (has links)
The Decentralized Fund Protocol is a novel decentralized finance protocol that enables the creation of completely decentralized funds. This paper proposes practical implementation solutions to the Fund Recalibration System, in particular the recalibration and depositing of assets into the fund to alter and shift the underlying asset backing of the fund. These proposed solutions are partially implemented and transaction fees, also known as gas costs are evaluated with Hardhat and ethers.js. Additionally security test are performed with the Smartbugs solidity test suite to ensure that the prototype has no obvious security issues. The thesis finds that the favourable implementation of the Fund Recalibration System is a solution that allows the fund move assets into the fund with the same cost independent of the number of participants in the system. This is achieved by utilizing an asset pool which participants manually pool assets into, paying for their own participation. The fund can consequently move all assets in the pool all at once into the fund and can thus perform the same computations independent of how many participants that contributed to the pool. / Protokollet Decentralized Fund Protocol är ett nytt decentraliserat finansprotokoll som gör det möjligt att skapa helt decentraliserade fonder. Detta arbete föreslår praktiska implementeringslösningar för fondrekalibrationssystemet (Fund Recalibration System), i synnerhet rekalibreringen och insättning av tillgångar i fonden för att förändra och skifta fondens underliggande tillgångar. Dessa föreslagna lösningar är delvis implementerade, och i samband med detta utvärderas transaktionsavgifter, även kända som gaskostnader, med Hardhat och ethers.js. Dessutom utförs säkerhetstest med Smartbugs solidity test suite för att säkerställa att prototypen inte har några uppenbara säkerhetsproblem. Raporten finner att den mest gynnsamma implementeringen av fondförvaltningssystemet är en lösning som tillåter fonden att slå samman tillgångar i fonden med samma kostnad oberoende av antalet deltagare i systemet. Detta uppnås genom att använda en tillgångspool som deltagarna manuellt samlar tillgångar till och betalar för sitt eget deltagande. Fonden kan följaktligen flytta alla tillgångar i poolen på en gång till fonden och kan därmed utföra samma beräkningar oberoende av hur många deltagare som bidragit till poolen.
15

Posouzení časových změn kalibračních charakteristik vodoměrných vrtulí / Assessing the time changes of calibration characteristics of current meters

Sedlák, Daniel January 2019 (has links)
Diploma’s thesis is focused on analysis of the time changes of calibration characteristics independent type of current-meters, processing by the calibration data and their evaluation and subsequent comparison with related research. This thesis describes the proces of calibration of current-meters.
16

Developmental welfare in Thailand after the 1997 Asian financial crisis

Tivayanond, Prapaporn January 2011 (has links)
This thesis explores continuity and change in the developmental welfare approach in Thailand following the 1997 Asian financial crisis. It examines both the exogenous and endogenous forces that generated change as well as both the ‘process’ and the ‘content’ of transformation or responses to the crisis. It uses the One Tambon One Product (OTOP) policy as a case study to explore these changes. The principle research question is: To what extent did the post 1997 crisis policy on social protection in Thailand represent a shift from its existing institutional path of developmental welfarism? Extending from this overarching question are subsidiary questions, which guided the thesis. They include: To what extent did the OTOP policy address the social protection gaps that became apparent in the Asian financial crisis? To what extent did the OTOP policy benefit its target population? The thesis uses historical institutionalism (HI) and the role of ideas as the analytic frameworks in analyzing change. The thesis argues that the exogenous shock of the 1997 financial crisis contributed to some departure from the institutional path of developmental welfarism in Thailand. However, the change did not follow the conventional punctuated equilibrium (PE) model under the HI framework in the sense of moving from one equilibrium to another after an exogenous shock. Rather, the radical change that took place after the exogenous shock was gradual. The new set of institutional arrangement prompted significant ideational and institutional transformations. They involved both intended and unintended consequences of incremental shifts in the forms of ‘layering’ ‘drift’ and ‘conversion’ (Streeck and Thelen, 2005). In addition, the thesis argues that the transformation in Thailand after the 1997 financial crisis lies in an intermediate order of change that is found between shifts in policy instrument and a wholesale ‘paradigm shift’ (Hall, 1993). Here, apart from having introduced a new policy such as OTOP, the Thai government engaged in a broader rethinking of Thailand’s developmental welfare path. Moreover, the study finds that the structure of economic development in a developing country context can both promote and impede social protection, rather than only subordinate the latter. The claim is based on the finding that the expansion of economic policy goals in Thailand supported local development and increasing inclusiveness of the informal sector after the 1997 financial crisis. Finally, the thesis argues that social protection delivery or lack thereof reflects contestation of ideas as well as material interests. Both the state and the policy beneficiaries in the OTOP context pushed for their interests when there were gaps between policy formulation and implementation. As a result, changes occurred both in the policy goals and in who benefited from OTOP.

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