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Development of ABAQUS-MATLAB Interface for Design Optimization using Hybrid Cellular Automata and Comparison with Bidirectional Evolutionary Structural OptimizationAntony, Alen 12 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Topology Optimization is an optimization technique used to synthesize models without any preconceived shape. These structures are synthesized keeping in mind the minimum compliance problems. With the rapid improvement in advanced manufacturing technology and increased need for lightweight high strength designs topology optimization is being used more than ever.
There exist a number of commercially available software's that can be used for optimizing a product. These software have a robust Finite Element Solver and can produce good results. However, these software offers little to no choice to the user when it comes to selecting the type of optimization method used.
It is possible to use a programming language like MATLAB to develop algorithms that use a specific type of optimization method but the user himself will be responsible for writing the FEA algorithms too. This leads to a situation where the flexibility over the optimization method is achieved but the robust FEA of the commercial FEA tool is lost.
There have been works done in the past that links ABAQUS with MATLAB but they are primarily used as a tool for finite element post-processing. Through this thesis, the aim is to develop an interface that can be used for solving optimization problems using different methods like hard-kill as well as the material penalization (SIMP) method. By doing so it's possible to harness the potential of a commercial FEA software and gives the user the requires flexibility to write or modify the codes to have an optimization method of his or her choice. Also, by implementing this interface, it can also be potentially used to unlock the capabilities of other Dassault Systèmes software's as the firm is implementing a tighter integration between all its products using the 3DExperience platform.
This thesis as described uses this interface to implement BESO and HCA based topology optimization. Since hybrid cellular atomata is the only other method other than equivalent static load method that can be used for crashworthiness optimization this work suits well for the role when extended into a non-linear region.
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Bi-Directional Vector Variable Gain Amplifier for an X-Band Phased Array Radar ApplicationMashayekhi, Arash 01 January 2014 (has links) (PDF)
This thesis presents the design, layout, and measurements of a bi-directional amplifier with variable vector (in-phase / quadrature) gain control that will be part of an electronically steered phased array system. The electronically steered phased array has many advantages over the conventional mechanically steered antennas including rapid scanning of the beam and adaptively creating nulls in desired locations. The 10-bit bi-directional Vector Variable Gain Amplifier (VVGA) is part of the transmit and receive module of each antenna element where transmit and receive functionality is determined through a simple switch. The VVGA performs amplification of the IF IQ pair by an adjustable complex coefficient. At receive, the VVGA functions as a Vector Variable Gain Current Amplifier (VVGCA) and at transmit, the VVGA functions as a Vector Variable Gain Transadmittance Amplifier (VVGTA). Design procedure, layout entry, schematic and parasitic extracted simulation results, and measurements are presented in this thesis.
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New Topology for STATCOM / Ny topologi för STATCOMIbáñez Sánchez, Marta January 2017 (has links)
Static compensators (STATCOM) based on high-power converters are widely used for utilitiesand industrial applications in order to enhance the power system reliability. Nowadays,the Chain-Link Modular Multilevel Converter is the best solution for such applications,providing high eciency and reliability, and good harmonic performance. However, thecurrent delta and wye congurations present diculties in controlling negative sequencein unbalanced networks, as well as high capacitance requirements, which results in bulkySTATCOMs.This thesis aims to analyse a new Chain-Link Modular Multilevel Converter for STATCOMapplications. The main feature of the proposed topology is the presence of a commondc-link that will allow the exchange of energy between phases, facilitating the compensationof negative sequence components. Consequently, the required zero sequence componentinjection for the current Chain-Link congurations are avoided, and thus, also theconsequent over-sizing of the converter. Moreover, it is expected to have lower capacitancerequirements, because of the elimination of the second order harmonic (100 Hz)component in most of the capacitors, as they are charged and discharged by a bi-phasecurrent instead of a single-phase one. Additionally, lower conduction losses are expectedby reducing the number of devices in the conduction path.The layout and operation of the new converter have been analysed in this thesis.A STATCOM Simulink model provided by ABB has been modied to satisfy the newtopology. The theoretical benets of the proposed converter are supported by dierentsimulations carried out in Matlab-Simulink. In particular, it is shown a 50 % of negativesequence capability without any zero sequence component injection. The total capacitanceof the converter can be reduced a 30 % in comparison with the delta Chain-LinkModular Multilevel Converter, which is the preferable topology in the market nowadays.Furthermore, the losses are kept quite low if SiC semiconductors are used.On the other hand, the proposed topology requires the usage of bi-directional switchesto do the commutation and allow the exchange of energy between phases. An in-depthanalysis of the commutation process is shown at the end of this thesis, concluding that BidirectionalControlled Thyristors would be a promising solution for this converter topology. / Reaktiv effektkompensering (STATCOM) baserade på högeffektomvandlare används vidaför samhällsservice och industriella användningar för att förbättra elsystemet pålitliga.Nuförtiden, Chain-Link Modular Multilevel Converter är den bästa lösningen för sådanaanvändningar, vilket ger hög verkningsgrad och mycket pålitliga, samt låg harmonisk distortion.Hursomhelst, den nuvarande delta och wye konfigurationer presentera svårigheteratt kontrollera negativ sekvens i obalanserade nätverk, vilket leder till överdimensioneringav omvandlaren. Vidare, dessa Chain-Link topologier har hög kapacitans kraven, vilketresulterar i skrymmande STATCOMs.Den här avhandlingen syftar till att analysera en ny Chain-Link Modular MultilevelConverter för STATCOM användningar. Det viktigaste kännetecken av den föreslagnatopologi är närvaron av en gemensam likspänningslänk som gör det möjligt utbytet avenergi mellan faserna, som underlättar ersättning av negativ sekvens komponenter. Pådetta sätt, den behövlig noll sekvens komponent injektion i de aktuella konfigurationernaundviks, och således, också den därav följande överdimensioneringen av omvandlaren.Dessutom, förväntas det att ha lägre kapacitans kraven, eftersom den första övertonens(100 Hz) komponent undviks i några av kondensatorerna, såsom de är laddas och urladdasav en bi-fas ström i stället för en enda-fas ett. Vidare, lägre ledningsförluster förväntasgenom att reducera antalet enheter i ledningsvågen.Layouten och drift av den nya omvandlaren beskrivs i denna avhandling. En Simulinkmodell från ABB har modifierats för att tillfredsställa den nya topologin. De teoretiskafördelarna med det föreslagna omvandlare topologi stöds av simuleringsresultat i Matlab-Simulink. I synnerhet, är det visas en 50 % av negativ sekvens kapacitet utan noll sekvenskomponent injektion. Den totala kapacitansen hos omvandlaren kan minskas på ett 30 %jämfört med den delta Chain-Link Modular Multilevel Converter, som är den föredragnatopologin på marknaden idag. Vidare är förlusterna hålls ganska låg om SiC halvledareanvänds.Å andra sidan, kräver den föreslagna topologi användningen av dubbelriktade omkopplareatt göra kommuteringen och möjliggöra utbytet av energi mellan faserna. Enfördjupad analys av kommuteringsförloppet visas i slutet av denna avhandling, slutsatsenatt Bi-directional Controlled Tyristors skulle vara en lovande lösning för topologin.
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Violence conjugale et détresse psychologique chez les jeunes couples : analyse de l'effet modérateur du soutien socialFortin, Isabel 08 1900 (has links)
Les jeunes adultes sont plus susceptibles de subir de la violence conjugale que les adultes plus âgés. Toutefois, l'effet de se confier à propos de la violence subie sur la santé mentale est peu connu. L'objectif de cette étude est d'explorer les liens entre la violence conjugale, le soutien social et la détresse psychologique selon le sexe dans un échantillon de 233 jeunes couples. Les résultats indiquent que, pour les femmes, la fréquence de la violence psychologique subie, mais pas celle de la violence physique, était positivement associée à la détresse psychologique. Pour ces femmes, recourir à un plus grand nombre de confidents diminue la force de la relation entre la violence et de leur niveau de détresse psychologique. Pour les hommes, les fréquences de la violence physique et psychologique subies étaient positivement liées à la détresse psychologique, mais contrairement aux femmes, plus ils se sont confiés à propos de la violence qu'ils ont subi, plus leur niveau de détresse est élevé. / Young adults are more likely to experience intimate partner violence (IPV) than older adults but little is known about the effect of confiding to others about the sustained violence on their mental health. The objective of this study was to explore the links between IPV, help-seeking and psychological distress by gender in a sample of 233 young couples. Our findings indicate that for women, the frequency of sustained psychological violence, but not of physical violence, was positively associated to psychological distress and that for these women, seeking help from a greater number of confidents decreased the strength of the association between violence and their level of psychological distress. Secondly, for men, the frequency of physical and psychological violence were both positively linked to psychological distress but unlike women, the more people they talked to about the violence they have sustained, the greater their level of distress was.
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A formalização fonético-fonológica da percepção de plosivas surdas sob múltiplas manipulações de voice onset time (VOT) por brasileiros e americanos à luz do modelo "Bhipon"MOTTA-AVILA, Camila 21 December 2017 (has links)
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Previous issue date: 2017-12-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES# / #2075167498588264571# / #600 / This Master’s Dissertation had as its main goal analyzing and formalizing how Brazilian learners of English language (L2) and Americans identify and discriminate the voicing patterns for plosive consonants under artificial manipulation in English monossilabic words. Americans normally follow the acoustic cue Voice Onset Time (VOT) to differentiate voiced plosives from voiceless ones. The VOT is measured in milisseconds and can be classified into three different categories (LISKER & ABRAMSON, 1964): negative VOT (for /b/, /d/ and /g/ in Portuguese); short-lag VOT (for /p/, /t/, /k/ in Portuguese and /b/, /d/, /g/ in English) and long-lag or positive VOT (for [ph], [th], [kh] in English). Previous studies (ALVES, BARATZ e MOTTA, 2012; SCHWARTZHAUPT, ALVES &FONTES, 2015; ALVES & MOTTA, 2014; MOTTA, 2014; ALVES & ZIMMER, 2015) demonstrated that the manipulation of VOT can result into different types of perceptual behaviour, depending on the group analyzed: Americans tend to follow this cue to attribute voicing patterns to consonants, while Brazilians tend to follow the voicing patters stablished for their L1. In order to analyze the perception in L2, this Dissertation was based on Speech Learning Model (SLM) – (FLEGE, 1995) and Perceptual Assimilation Model – L2 (PAM-L2) – (BEST e TYLER, 2007) studies. To investigate how perception was processed in Americans, explanations in Kent and Read (2015), Gussenhoven and Jacobs (2004), Matzenauer (2015) and Boersma, Escudero and Hayes (2003) were found. The method consisted of two perceptual tests: (a) Identification Test, (b) Discrimination Test. Both tests were designed with artificially manipulated stimuli. The types (pee, pit, tick, tip, kit, kill) were CVC (where V was a high vowel /ɪ/ or /i/). Each one of them was multiply manipulated, generating five tokens from one original type. This manipulation was gradually performed, in 25% layers, aiming to achieve the zero artificial VOT pattern. The Identification Test was designed with 60 target words and 12 distractors, resulting in 72 tokens per participant. The Discrimination Test was designed with 36 target trials and 9 catch-trials, in a total of 45 trials per participant. To summarize, results show that Americans can be considered to be more perceptually sensitive to the multiple VOT manipulation than Brazilians, who normally tend to follow their L1 way of attributing voicing patterns to plosives, regardless their proficiency level in English (basic, intermediate or advanced). In addition, different phonetic tresholds were found in each analyzed group and in each place of articulation observed (bilabial, alveolar, velar). Finally, this study tries to offer a formalization for perceptual grammars in each group, based on Bi-directional Phonology OT Model (BiPhon). It is expected that this study, its detailed data description and theoretical observations can contribute to and makefurther academic studies possible. / Esta Dissertação de Mestrado teve como principal objetivo analisar e formalizar de que forma brasileiros aprendizes de inglês (L2) e americanos identificam e discriminam o vozeamento das consoantes plosivas iniciais da língua inglesa sob múltiplas manipulações em palavras monossilábicas. Na língua inglesa, para a diferenciação de vozeamento, tem-se como principal pista acústica a aspiração, que pode ser medida a partir dos valores de Voice Onset Time (VOT). O VOT é medido em milissegundos e pode ser classificado em 3 diferentes padrões (LISKER & ABRAMSON, 1964): VOT NEGATIVO (que se realiza foneticamente em português em /b/, /d/ e /g/); VOT ZERO, (que se realiza como /p/, /t/ e /k/ no português e /b/, /d/ e /g/ no inglês) e o VOT POSITIVO (encontrado em [ph], [th] e [kh] no inglês). Estudos anteriores (ALVES, BARATZ e MOTTA, 2012; SCHWARTZHAUPT, ALVES &FONTES, 2015; ALVES & MOTTA, 2014; MOTTA, 2014; ALVES & ZIMMER, 2015) demonstraram que a manipulação da pista acústica VOT resulta em comportamentos perceptuais diferenciados de acordo com a natureza do participante: americanos tendem a seguir a pista acústica em questão ao atribuir ou não vozeamento para as consoantes plosivas, ao passo que os brasileiros continuam a seguir os padrões de vozeamento previstos para a sua L1. Para dar conta da percepção em inglês como L2, este trabalho fundamentou-se, basicamente, nos modelos perceptuais Speech Learning Model (SLM) – (FLEGE, 1995) e Perceptual Assimilation Model – L2 (PAM-L2) – (BEST e TYLER, 2007). Para analisar a percepção dos participantes americanos, buscaram-se explicações em Kent e Read (2015), Gussenhoven e Jacobs (2004), Matzenauer (2015) e Boersma, Escudero e Hayes (2003). O método aplicado neste estudo consistiu em dois testes de percepção: (a) Teste de Identificação, (b) Teste de Discriminação. Ambos foram montados com estímulos de palavras monossilábicas da língua inglesa (CVC), sendo V /ɪ/ ou /i/. Cada type (pee, pit, tick, tip, kit, kill) passou por manipulação múltipla da pista acústica VOT, gerando 5 tokens cada um. Tal manipulação se deu de forma gradual em camadas de 25%, objetivando-se alcançar o padrão de VOT zero artificial. O design do Teste de Identificação contou com 60 palavras-alvo e 12 distratoras, somando um total de 72 tokens por participante. O design do Teste de Discriminação, que teve por objetivo contrastar diferentes camadas de VOT entre si, contou com 36 tríades do tipo AxB e 9 catch-trials, somando 45 tríades por participante. Sucintamente, os resultados apresentados demonstraram que os participantes americanos são mais sensíveis ao corte da pista acústica VOT do que os participantes brasileiros, independentemente do nível de proficiência em língua inglesa (básico, intermediário e avançado). Além disso, limiares fonéticos distintos foram encontrados em cada um dos grupos analisados e em cada ponto de articulação observado (bilabial, alveolar, velar). Finalmente, propôs-se uma formalização da percepção de ambos os grupos para cada consoante analisada baseando-se no Modelo de OT Bidirecional (BiPhon), proposto por Boersma (2009) e Boersma e Hamman (2011). Espera-se, com este estudo, que a descrição detalhada dos dados e a reflexão teórica possam contribuir à Academia e possibilitar estudos futuros.
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Field Oriented Control Of A Permanent Magnet Synchronous Motor Using Space Vector Modulated Direct Ac-ac Matrix ConverterYildirim, Dogan 01 May 2012 (has links) (PDF)
The study designs and constructs a three-phase to three-phase direct AC&ndash / AC matrix converter based surface mounted permanent magnet synchronous motor (PMSM) drive system. First, the matrix converter topologies are analyzed and the state-space equations describing the system have been derived in terms of the input and output variables. After that, matrix converter commutation and modulation methods are investigated. A four-step commutation technique based on output current direction provides safe commutation between the matrix converter switches. Then, the matrix converter is simulated for both the open-loop and the closed-loop control. For the closed-loop control, a current regulator (PI controller) controls the output currents and their phase angles. Advanced pulse width modulation and control techniques, such as space vector pulse width modulation and field oriented control, have been used for the closed-loop control of the system. Next, a model of diode-rectified two-level voltage source inverter is developed for simulations. A comparative study of indirect space vector modulated direct matrix converter and space vector modulated diode-rectified two-level voltage source inverter is given in terms of input/output waveforms to verify that the matrix converter fulfills the two-level voltage source inverter operation. Following the verification of matrix converter operation comparing with the diode-rectified two-level voltage source inverter, the simulation model of permanent magnet motor drive system is implemented. Also, a direct matrix converter prototype is constructed for experimental verifications of the results. As a first step in experimental works, filter types are investigated and a three-phase input filter is constructed to reduce the harmonic pollution. Then, direct matrix converter power circuitry and gate-driver circuitry are designed and constructed. To control the matrix switches, the control algorithm is implemented using a DSP and a FPGA. This digital control system measures the output currents and the input voltages with the aid of sensors and controls the matrix converter switches to produce the required PWM pattern to synthesize the reference input current and output voltage vectors, as well. Finally, the simulation results are tested and supported by laboratory experiments involving both an R-L load and a permanent magnet synchronous motor load. During the tests, the line-to-line supply voltage is set to 26 V peak value and a 400 V/3.5 kW surface mounted permanent magnet motor is used.
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Violence conjugale et détresse psychologique chez les jeunes couples : analyse de l'effet modérateur du soutien socialFortin, Isabel 08 1900 (has links)
Les jeunes adultes sont plus susceptibles de subir de la violence conjugale que les adultes plus âgés. Toutefois, l'effet de se confier à propos de la violence subie sur la santé mentale est peu connu. L'objectif de cette étude est d'explorer les liens entre la violence conjugale, le soutien social et la détresse psychologique selon le sexe dans un échantillon de 233 jeunes couples. Les résultats indiquent que, pour les femmes, la fréquence de la violence psychologique subie, mais pas celle de la violence physique, était positivement associée à la détresse psychologique. Pour ces femmes, recourir à un plus grand nombre de confidents diminue la force de la relation entre la violence et de leur niveau de détresse psychologique. Pour les hommes, les fréquences de la violence physique et psychologique subies étaient positivement liées à la détresse psychologique, mais contrairement aux femmes, plus ils se sont confiés à propos de la violence qu'ils ont subi, plus leur niveau de détresse est élevé. / Young adults are more likely to experience intimate partner violence (IPV) than older adults but little is known about the effect of confiding to others about the sustained violence on their mental health. The objective of this study was to explore the links between IPV, help-seeking and psychological distress by gender in a sample of 233 young couples. Our findings indicate that for women, the frequency of sustained psychological violence, but not of physical violence, was positively associated to psychological distress and that for these women, seeking help from a greater number of confidents decreased the strength of the association between violence and their level of psychological distress. Secondly, for men, the frequency of physical and psychological violence were both positively linked to psychological distress but unlike women, the more people they talked to about the violence they have sustained, the greater their level of distress was.
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Comparative performance of ductile and damage protected bridge piers subjected to bi-directional earthquake attackMashiko, Naoto January 2006 (has links)
Incremental Dynamic Analysis (IDA) procedures are advanced and then applied to a quantitative risk assessment for bridge structures. This is achieved by combining IDA with site-dependent hazard-recurrence relations and damage outcomes. The IDA procedure is also developed as a way to select a critical earthquake motion record for a one-off destructive experiment. Three prototype bridge substructures are designed according to the loading and detailing requirements of New Zealand, Japan and Caltrans codes. From these designs 30 percent reduced scale specimens are constructed as part of an experimental investigation. The Pseudodynamic test is then to control on three specimens using the identified critical earthquake records. The results are presented in a probabilistic riskbased format. The differences in the seismic performance of the three different countries' design codes are examined. Each of these current seismic design codes strive for ductile behaviour of bridge substructures. Seismic response is expected to be resulting damage on structures, which may threaten post-earthquake serviceability. To overcome this major performance shortcoming, the seismic behaviour under bi-directional lateral loading is investigated for a bridge pier designed and constructed in accordance with Damage Avoidance principles. Due to the presence of steel armoured rocking interface at the base, it is demonstrated that damage can be avoided, but due to the lack of hysteresis it is necessary to add some supplemental damping. Experimental results of the armoured rocking pier under bi-directional loading are compared with a companion ductile design specimen.
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Examination of a Bi-Directional Relationship between Urgency and Alcohol UseBlackledge, Sabrina M. 12 1900 (has links)
The proposed study examined whether negative urgency and positive urgency are dynamic traits that hold bi-directional relationships with binge and prolonged alcohol use across time. Individuals between the ages of 18-30 were recruited from Amazon Mechanical Turk (MTurk; n = 179) and university student (n = 66) pools. Participants completed three batteries of self-report assessments approximately 30 days apart, each containing measures assessing negative and positive urgency, as well as drinking frequency and binge behavior during the prior month. Latent variable cross-lagged panel models examined the effects of alcohol use from the previous month on negative and positive urgency while controlling for concurrent and autoregressive effects. Results of the current study indicated that for the full sample, there was not an effect for the influence of binge/prolonged drinking on either negative or positive urgency during the subsequent month. However, when examined separately by sample (Turkers vs. university) and gender (male vs. female), significant effects were found more for individuals who were Turkers, male, and/or heavy drinkers, suggesting that increases in positive and negative urgency at Time 2 could be partially explained by variance in drinking patterns at Time 1 for these individuals. However, these relationships were not replicated again between Time 2 and Time 3 due to a decrease in all drinking behaviors during these times. Lastly, the study found that while urgency scores were related to psychosocial problems and dependence symptoms associated with drinking, there was no evidence to support that urgency scores had substantial relationships to specific frequency and/or bingeing behavior across the overall sample, although positive urgency had support for a relationship with bingeing, particularly among heavily drinking men. Thus, while the primary findings did not indicate any effects for a general sample of young adults, the effects observed among heavy male drinkers in the present study add to a growing body of literature indicating potential for interactive effects among personality, environmental, and sociobiological factors across the trajectory of the human lifespan. Future research that continues to examine urgency and how it relates to alcohol use in longitudinal contexts, utilizing diverse samples, is warranted.
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A Novel Control Method for Grid Side Inverters Under Generalized Unbalanced Operating ConditionsRutkovskiy, Yaroslav January 2020 (has links)
No description available.
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