The 2009 edition of the Manual on Uniform Traffic Control Devices (MUTCD) recommends a pedestrian walking speed of 3.5 feet per second for use in the timing of pedestrian clearance intervals at signalized intersections (reduced from 4.0 feet per second in the 2003 edition). Jurisdictions across the state of Utah continue to maintain pedestrian walking speeds of 4.0 feet per second for normal intersections with guidance on engineering judgement for areas where a lower pedestrian walking speed should be considered. In 2018, it was decided that the current state guidance with regard to pedestrian walking speeds be evaluated for any needed changes, such as adopting the national guidance found in the 2009 MUTCD. To evaluate pedestrian walking speeds at signalized intersections, 15 sites throughout the state of Utah were studied, producing a total of 2,061 observations of pedestrian crossing events. These crossing events were evaluated to calculate walking speeds in relation to pedestrian demographics at each location. Evaluated demographics included pedestrian group size, gender, mobility status, age category, alertness, and potential distractions. Upon completion of data collection, a statistical analysis was conducted to determine mean and 15th percentile pedestrian walking speeds by demographic. The data collection procedure, data analysis, and limited recommendations for pedestrian start-up delay and pedestrian walking speeds as used in signal timing are discussed in this report. The data suggest that Utah continue to maintain its guidance of 4.0 feet per second walking speeds at most signalized intersections, while exercising engineering judgment at locations containing high pedestrian volumes or locations containing high percentages of elderly or disabled pedestrians.

Responses of migratory birds to seasonal climate and long-term environmental changes have been a central theme of avian migration ecology. Atmospheric conditions (e.g., winds and thermals), climate, and land cover and land use (LCLU) are major factors influencing the flights of soaring birds. Soaring American White Pelicans (Pelecanus erythrorhynchos) (hereafter, AWPEs) migrate between the subtropical Gulf of Mexico (GOM) and the temperate Northern Great Plains. American White Pelicans are also economically important piscivorous birds, causing enormous damages to the commercial Channel Catfish (Ictalurus punctatus) aquaculture in the Southeastern US. My studies aimed to evaluate the effects of climate, wind, and LCLU on the geographic range distributions, seasonal movements, and annual survival of AWPEs. I used Bayesian integrated species distribution models to estimate the occupancy probability and space-use intensity of AWPEs at the breeding and non-breeding grounds in 2005, 2010, and 2015, respectively, with data from eBird, Breeding Bird Survey, and Christmas Bird Count. Decreases in wind speeds and surface net thermal radiation and increases in waterbodies, wetlands, and non-woody covers enhanced AWPE occupancy at both the breeding and non-breeding grounds. I used 72 GPS-tracked AWPE data to study circannual hourly movement speeds and seasonal home ranges of AWPEs from 2002 to 2012. American White Pelicans had shorter hourly movement distances and smaller seasonal home ranges in the Southern than Northern GOM during winters; however, the difference did not carry over to the shared breeding grounds during summers. Last, I built Bayesian integrated population models to estimate annual survival and population dynamics of AWPEs with mark-resight-recovery data and annual nest counts at Chase Lake, North Dakota, the US from 1960 to 2014. Increases in upward wind velocity during autumn migration enhanced hatch-year AWPE survival. Increased winter precipitation on the non-breeding grounds improved annual survival of yearling and adults. On the other hand, increased precipitation at the breeding grounds reduced annual survival of hatch-year AWPEs. My findings can help develop management plans for mitigating the economic damages of AWPEs by predicting what areas AWPEs may occupy with high abundances in the future changes in climate and LCLU.

臺灣地區過去三十年來，經濟發展快速，國民生活水準亦大幅提升，在各界戮力為經濟打拼，使我國經濟大幅起飛的同時，我們的社會發展卻在重經濟以及社會變遷影響下，逐漸產生一些可能阻礙社會整體健全發展的不正常現象，導致各種社會問題隨之出現，成為社會進步及創造優質生活的絆腳石，為提供政府及民間相關單位制訂或研擬社會問題防制政策時參考，本研究乃以「文獻法」、「主觀經驗法」及「主成份分析」，編製我國社會警報指標，以一數量化指標綜合評量我國社會問題潛在發展趨勢，並以「顯著水準法」訂定警戒線及對各年超過警戒線者發布警報訊號。 依據社會警報指標各領域社會問題警報分析結果， 87年各項社會問題警報速度超過「輕警」者有「家庭問題」及「犯罪問題」等二領域，尤其是「犯罪問題」更超過巨警，若綜合全體社會問題而言，87年綜合警報速度較前幾年緩和；另就近三年各領域社會問題警報速度觀察，平均較前三年快者有「家庭問題」、「犯罪問題」、「貧富不均問題」及「環境問題」等四領域，惟全體社會問題綜合結果，速度略緩。 / Exertion of the people has promoted the growth of the Taiwan economy for over three decades. However, social dysfunctions, resulted from all the emphases at the economic growth and the changes of the collective values, could have obstructed the development of the society as a whole. In order to served as the references in making social policies related, this study tries to organize "the Taiwan Social Warning Indicators" by statistic methods, such as literature search, subjective experience, and principal component. These quantitative indexes are expected to evaluate the potential tendency of the social issues in Taiwan. On the other hand, the statistical significance method is also applied to establish the warning lines and issue the warning signs when the annual increase rate of the indicator's value－the warning speed－ of the social issues are cross the warning line. In accordance with the analysis results of the social warning indicators in this study, the increase of warning speeds of the Taiwan social issues in 1998 regarding "family" and "crime" exceed the level of "light warning". The warning speed of the "crime issue" even exceeds the level of "extremely serious warning" among all. Furthermore, the warning speed of the comprehensive social issues in the same year is estimated at increasing more lightly than those of those issues in last few years. Another finding on the warning speeds of social issues in different fields is that the result of such a research from 1996 to 1998 is much worse in average on "family issue", "crime issue", "unequal fortune distribution issue", and "environmental issue" than that on the same issue from 1993 to 1995. But the warning speed of the social issues as a whole from 1996 to 1998 increases more slowly than that from 1993 to 1995.

<p><strong><p>Studie av koldioxidgradienter i havets ytskikt</p><p>Sofia Söderholm</p></strong></p><p>Denna studie bygger på ett nyligen utvecklat instrument som har mätt koldioxidkoncentrationer på tre olika djup i vattnet samt en nivå i luften. Då detta instrument var oprövat i vatten har en utvärdering av mätmetodens lämplighet för vattenmätningar utförts. Syftet med mätningarna var att undersöka ytvattnets vertikala koldioxidgradient för att med hjälp av denna kunna beskriva flödet av koldioxid mellan hav och atmosfär bättre. Detta flöde är en viktig del av den globala kolcykeln och en djupare förståelse för koldioxidflödets beteende kan i framtiden bidra till mer noggranna klimatprognoser. Hur de beräknade flödena från profilinstrumentet påverkas av temperaturgradienterna i vattnets ytskikt har även det studerats. Mätningarna utfördes i vattnet utanför mätstationen på Östergarnsholm, öster om Gotland. En del av studien fokuserar på de horisontella koldioxidgradienterna i ytvattnet som erhållits genom fartygsdata.</p><p>Instrumentet som har använts vid mätningarna bygger på hydrofoba, luftgenomträngliga membran och förefaller fungera mycket väl i vatten. Vid vindhastigheter som inte är högre än 3 - 4 m/s kan tydliga koldioxidgradienter i vattnets ytskikt ses, men detta samband behöver verifieras med en större mängd mätdata. Temperaturgradienten i vattnets ytskikt har ingen större påverkan på vare sig koldioxidgradienten eller flödet av koldioxid och dess effekt kan försummas i detta fall. De horisontella koldioxidgradienterna påverkas huvudsakligen av temperaturen, den biologiska aktiviteten samt transport av vattenmassor. På en större skala kan tydliga effekter av temperaturen på koldioxidhalterna ses och på en mindre skala samt nära kuster och under våren är den biologiska aktiviteten dominerande.</p><p><em><p>Nyckelord: Koldioxidgradient, koldioxidflöde, temperaturgradient, hydrofoba luftgenomträngliga membran, transferhastighet, vindhastighet, biologisk aktivitet.</p></em></p> / <p><strong><p>A study regarding the carbon dioxide gradients in the surface water.</p><p>Sofia Söderholm</p></strong></p><p>This study is based on a recently developed instrument that measures the concentration of carbon dioxide at three different depths in the water and one level in the air. Since this instrument has not previously been used for measurements in water, an evaluation regarding the usefulness of the instruments for measurements in water was made. The purpose of the measurements was to study the vertical gradient of carbon dioxide in the surface water and to describe the vertical flux of carbon dioxide between the ocean and the atmosphere in an improved way. This flux is an important part of the global carbon cycle and a deeper understanding of the behavior of the air-sea exchange of carbon dioxide could contribute to more accurate forecasts of the future climate. The impact on the calculated carbon dioxide flux by the temperature gradients in the surface waters was also analyzed. The measurements were performed in the waters outside of the island of Östergarnsholm, east of Gotland. Part of the study focuses on the horizontal carbon dioxide in the surface water, which was obtained by ship data.</p><p>The instrument used when performing the measurements is based on hydrophobic, air-permeable membranes and appears to function very well in water. During wind speeds below 3 - 4 m/s distinct carbon dioxide gradients can be seen for the investigated data, but more data is needed to quantify this gradient for different situations. The temperature gradient in the surface water doesn't have a significant effect on the carbon dioxide gradient or the flow of carbon dioxide, and the effect of the temperature gradient can in this particular case be neglected. The horizontal gradients of carbon dioxide are mainly affected by temperature, biological activity and transportation of water mass. On a larger scale the effects of temperature on the concentrations of carbon dioxide are visible and on a smaller scale along with the coastal areas and during springtime, the biological activity is the dominating influence.</p><p><em><p>Keywords: Carbon dioxide gradient, carbon dioxide flux, temperature gradient, hydrophobic airpermeable membranes , transfer velocity, wind speeds, biological activity.</p></em></p>

Studie av koldioxidgradienter i havets ytskikt Sofia Söderholm Denna studie bygger på ett nyligen utvecklat instrument som har mätt koldioxidkoncentrationer på tre olika djup i vattnet samt en nivå i luften. Då detta instrument var oprövat i vatten har en utvärdering av mätmetodens lämplighet för vattenmätningar utförts. Syftet med mätningarna var att undersöka ytvattnets vertikala koldioxidgradient för att med hjälp av denna kunna beskriva flödet av koldioxid mellan hav och atmosfär bättre. Detta flöde är en viktig del av den globala kolcykeln och en djupare förståelse för koldioxidflödets beteende kan i framtiden bidra till mer noggranna klimatprognoser. Hur de beräknade flödena från profilinstrumentet påverkas av temperaturgradienterna i vattnets ytskikt har även det studerats. Mätningarna utfördes i vattnet utanför mätstationen på Östergarnsholm, öster om Gotland. En del av studien fokuserar på de horisontella koldioxidgradienterna i ytvattnet som erhållits genom fartygsdata. Instrumentet som har använts vid mätningarna bygger på hydrofoba, luftgenomträngliga membran och förefaller fungera mycket väl i vatten. Vid vindhastigheter som inte är högre än 3 - 4 m/s kan tydliga koldioxidgradienter i vattnets ytskikt ses, men detta samband behöver verifieras med en större mängd mätdata. Temperaturgradienten i vattnets ytskikt har ingen större påverkan på vare sig koldioxidgradienten eller flödet av koldioxid och dess effekt kan försummas i detta fall. De horisontella koldioxidgradienterna påverkas huvudsakligen av temperaturen, den biologiska aktiviteten samt transport av vattenmassor. På en större skala kan tydliga effekter av temperaturen på koldioxidhalterna ses och på en mindre skala samt nära kuster och under våren är den biologiska aktiviteten dominerande. Nyckelord: Koldioxidgradient, koldioxidflöde, temperaturgradient, hydrofoba luftgenomträngliga membran, transferhastighet, vindhastighet, biologisk aktivitet. / A study regarding the carbon dioxide gradients in the surface water. Sofia Söderholm This study is based on a recently developed instrument that measures the concentration of carbon dioxide at three different depths in the water and one level in the air. Since this instrument has not previously been used for measurements in water, an evaluation regarding the usefulness of the instruments for measurements in water was made. The purpose of the measurements was to study the vertical gradient of carbon dioxide in the surface water and to describe the vertical flux of carbon dioxide between the ocean and the atmosphere in an improved way. This flux is an important part of the global carbon cycle and a deeper understanding of the behavior of the air-sea exchange of carbon dioxide could contribute to more accurate forecasts of the future climate. The impact on the calculated carbon dioxide flux by the temperature gradients in the surface waters was also analyzed. The measurements were performed in the waters outside of the island of Östergarnsholm, east of Gotland. Part of the study focuses on the horizontal carbon dioxide in the surface water, which was obtained by ship data. The instrument used when performing the measurements is based on hydrophobic, air-permeable membranes and appears to function very well in water. During wind speeds below 3 - 4 m/s distinct carbon dioxide gradients can be seen for the investigated data, but more data is needed to quantify this gradient for different situations. The temperature gradient in the surface water doesn't have a significant effect on the carbon dioxide gradient or the flow of carbon dioxide, and the effect of the temperature gradient can in this particular case be neglected. The horizontal gradients of carbon dioxide are mainly affected by temperature, biological activity and transportation of water mass. On a larger scale the effects of temperature on the concentrations of carbon dioxide are visible and on a smaller scale along with the coastal areas and during springtime, the biological activity is the dominating influence. Keywords: Carbon dioxide gradient, carbon dioxide flux, temperature gradient, hydrophobic airpermeable membranes , transfer velocity, wind speeds, biological activity.

Knowledge of flow separation is very essential for proper understanding of both external and internal aerothermodynamics of bodies. Because of unique flow features such as thick boundary layers, merged shock layers, strong entropy layers, flow separation in the flow field of bodies at hypersonic speeds, is both complex as well as interesting. The problem of flow separation is further complicated at very high stagnation enthalpies because of the real gas effects. Notwithstanding the plethora of information available in open literature even for simple geometric configurations the experimentally determined locations of flow separation and re-attachment points do not match well with the results from the computational studies even at hypersonic laminar flow conditions. In this backdrop the main aim of the present study is to generate a reliable experimental database of classical separated flow features around generic configurations at hypersonic laminar flow conditions. In the present study, flow visualization using high speed camera, surface convective heat transfer rate measurements using platinum thin film sensors, and direct skin friction measurements using PZT crystals have been carried out for characterizing the separated flow field around backward facing step, double cone and double wedge models. The numerical simulations by solving the Navier-Stokes equations have also been carried out to complement the experimental studies. The generic models selected in the present study are simple configurations, where most of the classical hypersonic separated flow features of two-dimensional, axi-symmetric and three dimensional flow fields can be observed. All the experiments are carried out in IISc hypersonic shock tunnel (HST2) at Mach 5.75 and 7.6. For present study, helium and air have been used as the driver and test gases respectively. The high speed schlieren flow visualization is carried out on backward facing step (2 and 3 mm step height), double cone (semi-apex angles of 150/350 and 250/680) and double wedge (semi-apex angles of 150/350) models by using high speed camera (Phantom 7.1). From the visualized shockwave structure in the flow field the flow reattachment point after separation has been clearly identified for backward facing step, double cone and double wedge models at hypersonic Mach numbers while the separation point could not be clearly identified because of the low free stream density in shock tunnels. However the flow visualization studies helped clearly identifying the region of flow separation on the model. Based on the results from the flow visualization studies both the physical location and distribution of platinum thin film gauges was finalized for the heat transfer rate measurements. Surface heat transfer rates along the length of two backward facing step (2 and 3 mm step height) models have been measured using platinum thin film gauges deposited on Macor substrate. The Eckert reference temperature method is used along the flat plate for predicting the heat flux distribution. Theoretical analysis of heat flux distribution down stream of the backward facing step model has been carried out using Gai’s dimensional analysis. The study reveals for the first time that at moderate stagnation enthalpy levels (~2 MJ/kg) the hypersonic separated flow around a backward facing step reattaches rather smoothly without any sudden spikes in the measured values of surface heat transfer rates. Based on the measured surface heating rates on the backward facing step, the reattachment distance was estimated to be approximately 10 and 8 step heights downstream of 2 and 3 mm step respectively at nominal Mach number of 7.6. Convective surface heat transfer experiments have also been carried out on axi-symmetric double cone models (semi-apex angles of 15/35 and 25/68), which is analogous to the Edney’s shock interactions of Type VI and Type IV respectively. The flow is unsteady on the double cone model of 25/68 and measured heat flux is not constant. The heat transfer experiments were also carried out on the three-dimensional double wedge model (semi-apex angles of 15/35). The separation and reattachment points have been clearly identified from the experimental heat transfer measurements. It has been observed that the measured heat transfer rates on the double wedge model is less than the double cone model (semi-apex angles of 150/350) for the identical experimental conditions at the same gauge locations. This difference could be due to the three-dimensional entropy relieving effects of double wedge model. PZT-5H piezoelectric based skin friction gauge is developed and used for direct skin friction measurements in hypersonic shock tunnel (HST2). The bare piezoelectric PZT-5H elements (5 mm × 5 mm with thickness of 0.75 mm) polarized in the shear mode have been used as a skin friction gauge by operating the sensor in the parallel shear mode direction. The natural frequency of the skin friction sensor is ~80 kHz, which is suitable for impulse facilities. The direct skin friction measurements are carried out on flat plate, backward facing step (2 mm step height) and double wedge models. The measured value of skin friction coefficient (integrated over an area of 25 sq. mm; sensor surface area) at a distance of 23 mm from the leading edge of the sharp leading edge backward facing step model is found to be ~ 0.0043 while it decreases to ~ 0.003 at a distance of 43 mm from the leading edge at a stagnation enthalpy of ~ 2MJ/kg. The measured skin friction matches with the Eckert reference temperature within ± 10%. The skin friction coefficient is also measured on the double wedge at a distance of 73 mm from the tip of the first wedge along the surface and is found to be 4.56 × 10-3. Viscous flow numerical simulations are carried out on two-dimensional backward facing step, axi-symmetric double cone and three-dimensional double wedge models using ANSYS-CFX 5.7 package. Navier-Stokes Simulations are carried out at Mach 5.75 and 7.6 using second order accurate (both in time and space) high resolution scheme. The flow is assumed to be laminar and steady throughout the model length except on the double cone (semi-apex angles of 250/680) model configuration, which represents the unsteady flow geometry. Analogous Edney Type VI and Type IV shock interactions are observed on double cone, double wedge (semi-apex angles of 150/350) and double cone (semi-apex angles of 250/680) models respectively from the CFD results. Experimentally measured convective heat transfer rates on the above models are compared with the numerical simulation results. The numerical simulation results matches well with the experimental heat transfer data in the attached flow regions. Considerable differences are observed between the measured surface heat transfer rates and numerical simulations both in the separated flow region and on the second cone/wedge surfaces. The separation and reattachment points can be clearly identified from both experimental measurements and numerical simulations. The results from the numerical simulations are also compared with results from the high speed flow visualization experiments. The experimental database of surface convective heating rates, direct skin friction coefficient and shockwave structure in laminar hypersonic flow conditions will be very useful for validating CFD codes

Ce projet de recherche-création est axé sur le développement d’un outil de création sonore, qui vise à faciliter l’improvisation de musiques électroacoustiques spatialisées sur de multiples haut-parleurs. L’outil nommé Live 4 Life permet plus spécifiquement de composer des polyrythmies spatialisées, combinées à des textures enveloppantes en temps réel. Actuellement, il est particulièrement difficile de contrôler dynamiquement et simultanément de multiples sons dans l’espace, en raison en partie de la stratification du processus de composition dans plusieurs logiciels et de la complexité à spatialiser individuellement chaque événement sonore. En dotant l’improvisateur d’outils de spatialisation flexibles, celui-ci peut exploiter les dimensions spatiales tout au long du processus de création, de la composition jusqu’à la performance. L’intégration, à même l’outil Live 4 Life, des autres paramètres sonores, comme le rythme ou les vitesses de lecture, permet également de créer de nouveaux liens dans la composition de l’espace. L’outil, implémenté sur la plate-forme en source libre SuperCollider, propose une approche comprenant différentes échelles temporelles, où la spatialisation est déterminée autant au niveau local sur des événements individuels que global sur des flux sonores. Des œuvres ouvertes du point de vue spatial et temporel peuvent ainsi être réalisées à partir de multiples séquences pré-composées, qui sont organisées et modifiées en temps réel. Cet outil de performance spatiale met l’accent sur la construction et la déformation de boucles de paramètres, rythmiques ou spatiales. Il permet, en outre, de questionner le développement spatio-temporel entre les objets sonores eux-mêmes, leurs traitements ou leurs réflexions et ouvre sur des questions plus larges sur les liens qui existent entre l’espace et le temps réel. / The research/creation project is focused on the development of a spatialised sound creation tool, which aims at facilitating the improvisation of electroacoustic music on multiple loudspeakers. More specifically, this tool, which is called Live 4 Life, allows to compose spatialised polyrhythms, combined with enveloping textures in real time. Currently, it is particularly difficult to dynamically and simultaneously control multiple sounds in space, due in part to the layering of the composition process in multiple software programs and the complexity of individually spatialising each sound event. By providing the improviser with flexible spatialisation tools, it allows him to exploit spatial dimensions throughout the creative process, from composition to performance. The integration of other sound parameters, such as rhythm, spectrum or playback speeds, in a global creation tool also allows to create new links in the composition of space. The tool, implemented on the open source platform SuperCollider, offers an approach comprising different time scales, where spatialisation is determined both locally on individual events and globally on sound streams. Spatially and temporally open forms can thus be realised from multiple pre-composed sequences, which are organised and modified in real time. This spatial performance tool emphasises the construction and deformation of parameter loops, rhythmic or spatial. It also makes it possible to question the spatio-temporal development between sound objects themselves, their processing or their reflections, and opens up broader questions on the links that exist between space and real time.

Wind power presently plays a minor role in Western Canada as compared to hydroelectric power in British Columbia and coal and natural gas thermal power generation in Alberta. However, ongoing reductions in the cost of wind power generation facilities and the increasing costs of conventional power generation, particularly if the cost to the environment is included, suggest that assessment of the present and future wind field in Western Canada is of some importance. To assess present wind power, raw hourly wind speeds and homogenized monthly mean wind speeds from 30 stations in Western Canada were analyzed over the period 1971-2000 (past). The hourly data were adjusted using the homogenized monthly means to attempt to compensate for differences in anemometer height from the standard height of 10m and changes in observing equipment at stations. A regional reanalysis product, the North American Regional Reanalysis (NARR), and simulations conducted with the Canadian Regional Climate Model (CRCM) driven with global reanalysis boundary forcing, were compared to the adjusted station wind-speed time-series and probability distributions. The NARR had a better temporal correlation with the observations, than the CRCM. We posit this is due to the NARR assimilating regional observations, whereas the CRCM did not. The NARR was generally worse than the CRCM in reproducing the observed speed distribution, possibly due to the crude representation of the regional topography in NARR. While the CRCM was run at both standard (45 km) and fine (15 km) resolution, the fine grid spacing does not always provide better results: the character of the surrounding topography appears to be an important factor for determining the level of agreement. Multiple simulations of the CRCM at the 45 km resolution were also driven by two global climate models (GCMs) over the periods 1971-2000 (using only historic emissions) and 2031-2060 (using the A2 emissions scenario). In light of the CRCM biases relative to the observations, these simulations were calibrated using quantile-quantile matching to the adjusted station observations to obtain ensembles of 9 and 25 projected wind speed distributions for the 2031-2060 period (future) at the station locations. Both bias correction and change factor techniques were used for calibration. At most station locations modest increases in mean wind speed were found for most of the projected distributions, but with a large variance. Estimates of wind power density for the projected speed distributions were made using a relationship between wind speed and power from a CRCM simulation for both time periods using the 15km grid. As would be expected from the wind speed results and the proportionality of wind power to the cube of wind speed, wind power at the station locations is more likely than not to increase in the 2031-2060 period from the 1971-2000 period. Relative changes in mean wind speeds at station locations were found to be insensitive to the station observations and choice of calibration technique, suggesting that we estimate relative change at all 45km grid points using all pairs of past/future mean wind speeds from the CRCM simulations. Overall, our results suggest that wind energy resources in Western Canada are reasonably likely to increase at least modestly in the future. / Graduate / 0725 / 0608 / jtdaines@uvic.ca

Fundação de Amparo a Pesquisa do Estado de Minas Gerais / This work investigates the operation of three phase induction motors in field weakening and high speed regions. Maximum torque per ampère is imposed by using an indirect vector control strategy. Mathematical models that accounts for magnetic saturation is used for simulations and adjustment of controllers used in control algorithm. The driving structure is characterized by the use of VSI static converter with sinusoidal PWM switching strategy and a vector control technique based on orthogonal components. Investigations resulted in the development of a digital simulation using discrete models that turned out generic and reliable, and an experimental system using a low cost fixed point DSP platform. Simulated and experimental results are included and shown the robustness and efficiency of the proposed control system under different operating conditions. / O presente trabalho tem como objetivo estudar a operação de motores de indução trifásicos em regime de enfraquecimento de campo e altas velocidades, com maximização do conjugado por ampère, através de um sistema de acionamento vetorial. Para tanto, foi utilizado uma modelagem matemática completa, por fase, que emprega o conceito de função harmônica magnética e considera as componentes, fundamental e de terceiro harmônico do fluxo de entreferro. A estrutura de acionamento caracteriza-se pela utilização de um inversor de tensão PWM senoidal e da técnica de controle vetorial, esta baseada em componentes ortogonais. A evolução do trabalho resultou no desenvolvimento de uma plataforma de simulação computacional baseada em modelos discretos que é bastante genérica e confiável, e um sistema experimental utilizando um processador digital de sinais de baixo custo com aritmética de ponto fixo. Os resultados de simulação e experimentais que avaliam a eficiência do sistema de controle proposto sob diversas condições de operação e efeitos de dessintonia são apresentados e apontam para robustez do método. / Doutor em Ciências