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Pilgrim, Michael. "The impact of differential friction on curve negotiation speed." Thesis, University of Canterbury. Engineering, 2014. http://hdl.handle.net/10092/10276.
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This thesis considers the impact of differential skid resistance between wheel paths on the speed at
which a vehicle can safely negotiate a curve. Currently the New Zealand Transport Agency undertakes
measurement of the co-efficient of friction on the state highway network by measuring both wheel
paths, but taking the average value to represent the level of skid resistance available. Part of the basis
for this approach is that modern cars have Electronic Stability Control that has historically been
considered to negate the effects of any differential friction.
Aside from straight line braking testing, little research has been done on the impacts of differential
friction on curves. There are however a number of areas of research that can be related to this topic.By PC Crash simulation modeling, this research identifies that there are a number of gaps in our understanding of the relationship between vehicles maneuvering on a curve and the effect of varying skid resistance.
It concludes that taking the average of the two values is not the same as considering them separately and, that as the difference in the co-efficient of friction between the wheel paths increases, the speed at which a vehicle can safely maneuver around a curve decreases. It has also been found that when Electronic Stability Control is used the speed at which the vehicle can safely maneuver around a curve decreases further.
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Neurauter, Michael Lucas. "Multidimensional Warnings: Determining an Appropriate Stimulus for a Curve-Warning Device." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/10164.
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An average of 42,000 fatalities occur on the United States of America's roads each year as a result of motor-vehicle crashes (National Highway Traffic Safety Administration, 2003). The dangers with respect to curves exist, from late notification of direction and speed, varying methods for determining advisory speeds, as well as driver unfamiliarity and/or over confidence. A curve-warning device, a device that notifies the driver of an upcoming curve and, possibly, conveys its vehicle-specific advisory speed and even direction, has the potential to drastically reduce the dangers of curve navigation. This study was performed as a proof of concept with regard to appropriate modalities and respective stimuli for a curve warning application.
For this study, objective and subjective measurements were collected in a simulator environment to compare conditions comprised of multiple stimuli from the auditory (icon, tone, and speech), visual (Heads Down Display and Heads Up Display), and haptic (throttle push-back) modalities. The results of the study show that the speech stimulus was the most appropriate of the auditory stimuli for both objective and subjective measurements. Objectively, the HDD and HUD were comparable with respect to performance, although the participants tended to favor the HDD in their subjective ratings. The throttle push-back did little to positively impact the performance measurements, and based on participant comments and ratings, it is not recommended for a curve-warning application. Of the stimulus conditions (combinations of two and three modalities), the Speech and HDD condition provided performance gains and subjective acceptability above the rest of the conditions.Master of Science
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Kanter, Claudia. "Extraction of Driving Modes for Dynamic Speed Adaptation in Curves." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215059.
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Modern cars have a multitude of driver assistance functions that aim to support the driver in his/her everyday driving. One part of this is the Adaptive Cruise Control (ACC) that aims to keep a driver-specified speed. However, this set speed might be perceived as too high for some curves and as a result the driver will interrupt the system and take control again. To avoid this, a Curve Speed Adaptation (CSA) system aims to adapt the speed for an upcoming curve. Such a system should aim to mimic a driver and take into consideration how the driver would behave if he/she were to drive. This work aims to find a set of so-called Driving Modes that can describe how drivers with different driving styles drive through curves with different road properties by analysing recorded manual driving. A nested clustering approach is tested to divide curves into groups based on the driving style they were driven at and their road properties. The results show that this approach is able to capture different driving behaviours through curves. The road type and speed limit of a curve seem thereby to have the main influence on the driving behaviour. Clustering curves first by their driving style followed by the road properties yields thereby the more distinguishable Driving Modes. However, further improvements of the clustering methods are necessary to improve the obtained Driving Modes. The results of this thesis can form the basis for the development of a Curve Speed Adaptation system that adjusts for both the individual driver as well as particular road properties to improve the driver's comfort.Moderna bilar har en mängd förarstödsystemer som syftar till att stödja föraren i sin dagligakörning. En av dem är Adaptive Cruise Control (ACC) som syftar till att hålla en hastighetspecificerad av föraren. Men denna hastighet kan uppfattas som för hög för vissa kurvoroch som resultat tar föraren kontrollen igen själv. För att undvika detta ska ett Curve SpeedAdaptation (CSA) system anpassa hastigheten för en kommande kurva. Ett sådant systembör sträva efter att efterlikna en förare och ta hänsyn till hur föraren skulle köra själv. Dethär examensarbetet syftar till att hitta så kallade körlägen som kan beskriva hur förare medolika körstilar kör genom kurvor med olika omständigheter genom att analysera manuellakörningar. En nestad klustringsmetod testas för att dela upp kurvor i grupper baserat påkörstilen som de kördes på och deras vägegenskaper. Resultaten visar att denna metod kanfånga olika körningsbeteenden genom kurvor. Vägtypen och hastighetsbegränsningen fören kurva verkar därmed ha huvudinverkan på körbeteendet. Att dela kurvorna först efterderas körstil följt av vägegenskaper ger bättre körlägena. Men ytterligare förbättringar avklustringsmetoderna är nödvändig för att förbättra de erhållna körningsmetoderna. Resul-taten av detta examensarbetet kan utgöra grunden för utvecklingen av ett kurvhastighetsanpassningssystem som anpassar både för den enskilda föraren och speciella vägegenskaperför att förbättra förarens komfort.
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Tukuafu, Jesse Tipasa. "The Effects of Indoor Track Curve Radius on Sprint Speed and Ground Reaction Forces." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2348.
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Sprinting on a curve is significantly slower than on a straightaway. Although the dimensions vary from track to track, indoor track curves are among the tightest curves that athletes will sprint at maximal speed. Previous studies have provided theories for how speed attenuation occurs when running on a curve. Yet, no previous research has determined how the variability of indoor track curve radii affects trained sprinters at maximal speeds. Purpose: To determine the differences in running speeds, ground time (GT), and medio-lateral (ML) impulse, with different indoor track radii. A secondary purpose was to understand the between-leg differences in GT and ML impulse during maximal sprinting on a curve. Methods: 10 male intercollegiate sprinters performed 45-m maximal sprints on a straightaway, 15-m track curve and 21-m track curve. A force platform embedded under an indoor track surface measured ground reaction forces while timing lights measured running speed. Analysis: A mixed models analysis of variance blocking on subjects was performed testing the main effects of the track curve on sprinting speed, GT and ML impulse (p<0.01). Results: Sprinting speed was significantly slower when running on a curve. GT increased for inside leg on both curved path conditions compared to straight. ML impulses increased as the radius of the track curve decreased. Discussion: If a 200m race were performed on both our track curves, the track with 21m curve would be 0.12s faster than the track with the 15m curve. GT and ML impulse results support leading explanations that the inside leg is the limiting factor during curve running. Tighter track curves require greater ML forces, but for a shorter period of time compared to larger track turns. Coaches and athletes should consider the radius of the track curve as they prepare for training and performance and consider injury risk. The speed differences observed due to the track curve radius may provide the first step to understanding how the radius of the indoor track curve affects sprinting speed and ultimately, performance.
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Trumpoldt, Julie Marie. "Development of a Tool to Calculate Appropriate Advisory Speeds on Horizontal Curves." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/71768.
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Horizontal curves are a contributing factor for numerous deaths on roadways. The curve characteristics dictate the severity of the curve and require the driver to be more attentive while driving. To address this issue, advisory speeds are posted on horizontal curves to warn drivers to slow down for their safety. There are six main procedures to assign advisory speeds. This paper focuses on two of these methods, finds a connection between the two, and develops an Android Application that can be used to determine an advisory speed for a curve. In this work, a brief summary of the six existing methods for advisory speed assignment are discussed. Pros and cons are included for each for comparison purposes. Next, two of these methods are highlighted by applying them in the field. Data is collected and a relationship between them is determined. Using this relationship, an Android Application is created and the various details of the design process are described. This Application, called CurveAdvisor, allows the user to assign the appropriate advisory speed on a desired horizontal curve. An analysis is then conducted to test the effectiveness of CurveAdvisor. Results indicate that CurveAdvisor is successful in many cases. Finally, contributions and suggestions for future work are included.Master of Science
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Lee, Peter T. (Peter Taeyun). "Comparison of various media in teaching engineering principles : design of a D.C. motor torque/speed curve display mechanism." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/49680.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1998.Improving product development education depends on finding effective media with which to teach. In my thesis, I focused on a comparison between the physical intimacy with a mechanical system and a computer simulation of the same system - specifically DC motors and their torque/speed characteristics. I built a fully mechanical dynamometer that draws the torque/speed curve of a DC motor as a student grabs the motor shaft. I also designed an interactive dynamic computer simulation of the same device using a modeling and animation software package. The design of the mechanical mechanism was a task that required engineering analysis, industrial design, human factors, and a focus on the education of students. There were a number of design challenges in this device that led me to build a fairly sophisticated mechanical mechanism that draws a torque/speed curve while being simple enough to understand. The design approach and analysis method was heavily stressed in creating this model. The computer simulation was modeled directly from the mechanical model. In order to compare the teaching effectiveness of the models, I ran experiments with students comparing the mechanical device, the computer simulation, and a control, a written textbook explanation of DC motor torque/speed characteristics. From the experiments, I found that the mechanical model was most effective in teaching students, followed by the computer simulations, and finally the control test. Students felt that the hand-on aspect of the mechanical model was the most important feature that distinguished it from the others. The results from this thesis can help to guide how media might be used more effectively in education.
by Peter T. Lee.
S.M.
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Gong, Huafeng. "OPERATING SPEED PREDICTION MODELS FOR HORIZONTAL CURVES ON RURAL FOUR-LANE NON-FREEWAY HIGHWAYS." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_diss/562.
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One of the significant weaknesses of the design speed concept is that it uses the design speed of the most restrictive geometric element as the design speed of the entire road. This leads to potential inconsistencies among successive sections of a road. Previous studies documented that a uniform design speed does not guarantee consistency on rural two-lane facilities. It is therefore reasonable to assume that similar inconsistencies could be found on rural four-lane non-freeway highways. The operating speed-based method is popularly used in other countries for examining design consistency. Numerous studies have been completed on rural two-lane highways for predicting operating speeds. However, little is known for rural four-lane non-freeway highways. This study aims to develop operating speed prediction models for horizontal curves on rural four-lane non-freeway highways using 74 horizontal curves. The data analysis showed that the operating speeds in each direction of travel had no statistical differences. However, the operating speeds on inside and outside lanes were significantly different. On each of the two lanes, the operating speeds at the beginning, middle, and ending points of the curve were statistically the same. The relationships between operating speed and design speed for inside and outside lanes were different. For the inside lane, the operating speed was statistically equal to the design speed. By contrary, for the outside lane, the operating speed was significantly lower than the design speed. However, the relationships between operating speed and posted speed limit for both inside and outside lanes were similar. It was found that the operating speed was higher than the posted speed limit. Two models were developed for predicting operating speed, since the operating speeds on inside and outside lanes were different. For the inside lane, the significant factors are: shoulder type, median type, pavement type, approaching section grade, and curve length. For the outside lane, the factors included shoulder type, median type, approaching section grade, curve length, curve radius and presence of approaching curve. These factors indicate that the curve itself does mainly influence the drivers speed choice.
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Vieira, Fábio Sartori. "Evaluation of drivers\' behavior performing a curve under mental workload." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/18/18143/tde-07072016-151918/.
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Driving under distraction may lead drivers to wrong actions that can result in serious accidents. The objective of this thesis was to apply a driving simulator to verify variations in drivers\' behavior while driving. Behavior to drive on a curve was measured by variation in drivers\' speed profile in a virtualized highway. The comparison was performed between two identical simulations, one involving drivers distracted with a mental workload, and other in which they were full aware of driving task. 54 volunteer drivers took part in this study, which was divided into 4 stages. 17 drivers performed the distraction test known as PASAT, and results showed that distracted drivers did not recognize the beginning of the curve and drove through it at speeds higher than those when they were fully aware. Moreover, driving performance was increased when drivers were aware of driving, thereby hitting high speeds in tangents, but perceiving curves in advance to reduce acceleration. This study confirms that driving simulators are beneficial in discovering drivers\' behavior exposed to activities that could be highly risky if driving in real situations.A distração durante a atividade de direção pode levar o condutor de veículos automotores a cometer falhas, que podem ocasionar até mesmo acidentes graves. Este estudo aborda a utilização de simuladores de direção para verificar variações no comportamento de motoristas ao realizar a atividade de direção, distraídos ou com plena atenção na condução do veículo. O comportamento é medido pela variação no perfil de velocidade dos condutores para desenvolver uma curva considerada perigosa em uma rodovia simulada em ambiente virtual. A variação de velocidade deste perfil é comparada entre duas simulações idênticas, onde em uma delas os condutores estão distraídos com um teste que proporciona estresse mental e, na outra, estão com plena atenção à direção. 54 condutores fizeram parte deste estudo dividido em 3 etapas. 17 participantes realizaram o teste de distração conhecido como PASAT, e a análise dos resultados mostram que, distraídos, os condutores não perceberam o início da curva e desenvolveram velocidades maiores durante seu trajeto. Além disso, quando estavam com plena atenção à atividade de direção, o desempenho dos condutores foi melhor, atingindo velocidades maiores nas tangentes, mas percebendo as curvas antecipadamente e reduzindo suas velocidades antes de iniciar esses trechos.
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Narmack, Kirilll. "Dynamic Speed Adaptation for Curves using Machine Learning." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233545.
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The vehicles of tomorrow will be more sophisticated, intelligent and safe than the vehicles of today. The future is leaning towards fully autonomous vehicles. This degree project provides a data driven solution for a speed adaptation system that can be used to compute a vehicle speed for curves, suitable for the underlying driving style of the driver, road properties and weather conditions. A speed adaptation system for curves aims to compute a vehicle speed suitable for curves that can be used in Advanced Driver Assistance Systems (ADAS) or in Autonomous Driving (AD) applications. This degree project was carried out at Volvo Car Corporation. Literature in the field of speed adaptation systems and factors affecting the vehicle speed in curves was reviewed. Naturalistic driving data was both collected by driving and extracted from Volvo's data base and further processed. A novel speed adaptation system for curves was invented, implemented and evaluated. This speed adaptation system is able to compute a vehicle speed suitable for the underlying driving style of the driver, road properties and weather conditions. Two different artificial neural networks and two mathematical models were used to compute the desired vehicle speed in curves. These methods were compared and evaluated.Morgondagens fordon kommer att vara mer sofistikerade, intelligenta och säkra än dagens fordon. Framtiden lutar mot fullständigt autonoma fordon. Detta examensarbete tillhandahåller en datadriven lösning för ett hastighetsanpassningssystem som kan beräkna ett fordons hastighet i kurvor som är lämpligt för förarens körstil, vägens egenskaper och rådande väder. Ett hastighetsanpassningssystem för kurvor har som mål att beräkna en fordonshastighet för kurvor som kan användas i Advanced Driver Assistance Systems (ADAS) eller Autonomous Driving (AD) applikationer. Detta examensarbete utfördes på Volvo Car Corporation. Litteratur kring hastighetsanpassningssystem samt faktorer som påverkar ett fordons hastighet i kurvor studerades. Naturalistisk bilkörningsdata samlades genom att köra bil samt extraherades från Volvos databas och bearbetades. Ett nytt hastighetsanpassningssystem uppfanns, implementerades samt utvärderades. Hastighetsanpassningssystemet visade sig vara kapabelt till att beräkna en lämplig fordonshastighet för förarens körstil under rådande väderförhållanden och vägens egenskaper. Två olika artificiella neuronnätverk samt två matematiska modeller användes för att beräkna fordonets hastighet. Dessa metoder jämfördes och utvärderades.
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Koppermann, Claus Philipp [Verfasser], Georg [Akademischer Betreuer] Sigl, Marian [Gutachter] Margraf, and Georg [Gutachter] Sigl. "Curve Based Cryptography: High-Performance Implementations and Speed Enhancing Methods / Claus Philipp Koppermann ; Gutachter: Marian Margraf, Georg Sigl ; Betreuer: Georg Sigl." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/1190285223/34.
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Hitchcock, Yvonne Roslyn. "Elliptic Curve Cryptography for Lightweight Applications." Queensland University of Technology, 2003. http://eprints.qut.edu.au/15838/.
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Elliptic curves were first proposed as a basis for public key cryptography in the mid 1980's. They provide public key cryptosystems based on the difficulty of the elliptic curve discrete logarithm problem (ECDLP) , which is so called because of its similarity to the discrete logarithm problem (DLP) over the integers modulo a large prime. One benefit of elliptic curve cryptosystems (ECCs) is that they can use a much shorter key length than other public key cryptosystems to provide an equivalent level of security. For example, 160 bit ECCs are believed to provide about the same level of security as 1024 bit RSA. Also, the level of security provided by an ECC increases faster with key size than for integer based discrete logarithm (dl) or RSA cryptosystems. ECCs can also provide a faster implementation than RSA or dl systems, and use less bandwidth and power. These issues can be crucial in lightweight applications such as smart cards. In the last few years, ECCs have been included or proposed for inclusion in internationally recognized standards. Thus elliptic curve cryptography is set to become an integral part of lightweight applications in the immediate future. This thesis presents an analysis of several important issues for ECCs on lightweight devices. It begins with an introduction to elliptic curves and the algorithms required to implement an ECC. It then gives an analysis of the speed, code size and memory usage of various possible implementation options. Enough details are presented to enable an implementer to choose for implementation those algorithms which give the greatest speed whilst conforming to the code size and ram restrictions of a particular lightweight device. Recommendations are made for new functions to be included on coprocessors for lightweight devices to support ECC implementations Another issue of concern for implementers is the side-channel attacks that have recently been proposed. They obtain information about the cryptosystem by measuring side-channel information such as power consumption and processing time and the information is then used to break implementations that have not incorporated appropriate defences. A new method of defence to protect an implementation from the simple power analysis (spa) method of attack is presented in this thesis. It requires 44% fewer additions and 11% more doublings than the commonly recommended defence of performing a point addition in every loop of the binary scalar multiplication algorithm. The algorithm forms a contribution to the current range of possible spa defences which has a good speed but low memory usage. Another topic of paramount importance to ECCs for lightweight applications is whether the security of fixed curves is equivalent to that of random curves. Because of the inability of lightweight devices to generate secure random curves, fixed curves are used in such devices. These curves provide the additional advantage of requiring less bandwidth, code size and processing time. However, it is intuitively obvious that a large precomputation to aid in the breaking of the elliptic curve discrete logarithm problem (ECDLP) can be made for a fixed curve which would be unavailable for a random curve. Therefore, it would appear that fixed curves are less secure than random curves, but quantifying the loss of security is much more difficult. The thesis performs an examination of fixed curve security taking this observation into account, and includes a definition of equivalent security and an analysis of a variation of Pollard's rho method where computations from solutions of previous ECDLPs can be used to solve subsequent ECDLPs on the same curve. A lower bound on the expected time to solve such ECDLPs using this method is presented, as well as an approximation of the expected time remaining to solve an ECDLP when a given size of precomputation is available. It is concluded that adding a total of 11 bits to the size of a fixed curve provides an equivalent level of security compared to random curves. The final part of the thesis deals with proofs of security of key exchange protocols in the Canetti-Krawczyk proof model. This model has been used since it offers the advantage of a modular proof with reusable components. Firstly a password-based authentication mechanism and its security proof are discussed, followed by an analysis of the use of the authentication mechanism in key exchange protocols. The Canetti-Krawczyk model is then used to examine secure tripartite (three party) key exchange protocols. Tripartite key exchange protocols are particularly suited to ECCs because of the availability of bilinear mappings on elliptic curves, which allow more efficient tripartite key exchange protocols.
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Bennett, Casey. "Channel Noise and Firing Irregularity in Hybrid Markov Models of the Morris-Lecar Neuron." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1441551744.
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Tomešek, Zdeněk. "Vyhledávací studie obchvatu města Hustopeče." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225418.
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This graduation thesis deals about researching study of by-pass road of city Hustopeče, district of Břeclav, Southmoravian region. This city passes main road number 425, which should be connected with the by-pass road. The by-pass road will be designed as road of category S9,5/70 and will be situated west of the city. Terrain is undulated and composed of agricultural parcels. The main purpose of this by-pass road is significant burden of region traffic.
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Kokeš, Ondřej. "Optimalizace vybraných návrhových prvků ČSN pro projektování pozemních komunikací." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227622.
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Diploma thesis describes and researches some proposed ČSN 73 6101 elements for road design and their subsequent comparison with Norma de Traçado that is main law for road design in Portugal. In practical part, the speed of vehicles during moving on direction curves is researched and subsequently coherence of theoretical assumptions with real speeds is compared. The main aim of this work is to verify the assumption that design speed does not correspond to the real speed that drivers move on road structures.
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Stránský, Jakub. "Optimalizace vybraných návrhových prvků ČSN pro projektování pozemních komunikací." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227496.
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The master‘s thesis focuses on the optimization of the design values of curves of the horizontal alignments of the roads. It deals with the comparison of values between czech and foreign standards and differences between them. The practical part examines the values of the real speeds of vehicles passing through the curves of various parameters that were measured during measurements of selected curves during 2014. From these data a new design values are derived that could be used for the design of horizontal alignments.
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Almén, Marcus. "Driver Model for Mission-Based Driving Cycles." Thesis, Linköpings universitet, Fordonssystem, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-140158.
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When further demands are placed on emissions and performance of cars, trucks and busses, the vehicle manufacturers are looking to have cheap ways to evaluate their products for specific customers' needs. Using simulation tools to quickly compare use cases instead of manually recording data is a possible way forward. However, existing traffic simulation tools do not provide enough detail in each vehicle for the driving to represent real life driving patterns with regards to road features. For the purpose of this thesis data has been recorded by having different people drive a specific route featuring highway driving, traffic lights and many curves. Using this data, models have then been estimated that describe how human drivers adjust their speed through curves, how long braking distances typically are with respect to the driving speed, and the varying deceleration during braking sequences. An additional model has also been created that produces a speed variation when driving on highways. In the end all models are implemented in Matlab using a traffic control interface to interact with the traffic simulation tool SUMO. The results of this work are promising with the improved simulation being able to replicate the most significant characteristics seen from human drivers when approaching curves, traffic lights and intersections.
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Kunzler, Júnior Júlio Vítor. "Análises teórica e experimental do Gerador Assíncrono de Dupla Alimentação - o GEADA, e contribuição à sua operação." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2006. http://hdl.handle.net/10183/8686.
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Este trabalho apresenta a análise teórica e experimental do gerador assíncrono de dupla alimentação, denominado GEADA ao longo deste trabalho, operando em regime permanente com velocidade não fixa, mas com freqüência da armadura constante. Compreende o escopo do trabalho a análise teórica a partir do circuito equivalente do gerador, a análise teórica e experimental da curva de magnetização do GEADA operando em freqüência do rotor variável, uma proposta de adaptação da curva de capacidade aplicada na operação dos geradores síncronos para o GEADA e a sua análise considerando-o como máquina síncrona a partir dos seus terminais, os ensaios normalizados e complementares necessários para o levantamento dos parâmetros para este circuito equivalente e ensaios do GEADA operando com carga para verificação de seu desempenho Os resultados obtidos permitem um melhor entendimento desse sistema de geração, de suas condições de operação e utilização em sistemas de geração de velocidade não fixa como, por exemplo, sistemas eólicos e hidrelétricos.The study presents the theoretical and experimental analysis of the double fed asynchronous generator, called GEADA, operating in steady state with non-fixed speed but with constant armature frequency. It comprehends the theoretical analysis based on the equivalent circuit of this generator, the theoretical and experimental analysis of the curve of magnetization of the GEADA operating with variable rotor frequency. A proposal of adaptation of the capability curve applied in the operation of the synchronous generators for the GEADA is also presented, its analysis considering it as a synchronous machine from its terminals, the standard and complementary tests necessary for the calculation of the parameters for the equivalent circuit and the tests with the GEADA operating under on-load conditions to verify its performance. The achieved results allow a better understanding of this generation system, its operational conditions and applicability to the power generation systems based on variable speed, such as wind and hydroelectric power plants.
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Persaud, Vasu Tavasna. "DYNAMIC SPEED MONITORING SYSTEM EFFECTIVENESS ON SHARP CURVES." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2931.
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The design of rural interchanges is of critical concern due to the need for the safe transition of vehicles from one high speed roadways to another and vice versa. This transition is accomplished by entry and exit ramps of various forms. The southbound entry loop ramp at the US 27/ US 192 trumpet interchange in Polk County, Florida does not provide such safe transition since historically there has been a high incidence of vehicular off-tracking. The geometry of the southbound entry ramp coupled with high approach speeds are two of the contributing factors. Due to the high cost of interchange modification and ramp realignment, one approach to increasing safety at the interchange is to decrease approach speeds (assumes that speed is a surrogate measure of safety) utilizing a Dynamic Speed Monitoring (DSM) system. The objective of this thesis was to test the effectiveness of such a DSM system at reducing vehicle speeds at the rural US 27/ US 192 trumpet interchange in Polk County, Florida. The system tested was a solar powered, radar based, wireless speed warning system which potentially could be used at traffic locations where it is difficult to secure power and to extended wires. The Measures of Effectiveness (MOEs) for the system were the reduction in mean and variance of speed along with the proportion of vehicles in the higher speed ranges after system implementation. This thesis describes the testing of the DSM effectiveness and involves the documentation of the experiments conducted, the data collected and the analysis of the results. Speed data was collected Before and After installation of the DSM system at two points preceding the southbound entry ramp. Approach speeds were collected at a point 250 feet in advance of the southbound entry ramp curve (also the detection zone of the DSM system radar) and PC speeds were collected at the Point of Curve of southbound entry ramp. Various data sets were analyzed in order to ascertain the systems effectiveness during the day and night, weekdays and weekends, various time periods during the day, and within various speed ranges. The Approach and PC data analysis indicated that the DSM system significantly (at the 95% confidence level) reduced speed mean and variance and increased speed limit/ advisory speed compliance. The Approach mean speed was reduced by 3.58 mph and the PC mean speed was reduced by 1.57 mph. The Approach speed variance was reduced by 3.34 and the PC speed variance was reduced by 0.70 mph. Approach speed limit compliance was increased by 22.27% and PC advisory speed (35 mph) + 5 mph compliance was increased by 11.56% (it was apparent that motorist were utilizing speeds above the advisory speed to navigate the curve). In general, the effectiveness of the DSM system was diminished on weekends as well as during the late night and early morning (12 AM to 7 AM) time periods. This suggested that when there were lower volumes and when motorists' perceived that speed limit enforcement was not as likely, the DSM system effectiveness was reduced. The DSM system resulted in a reduction in the percentage of vehicles utilizing the higher speed ranges (> 45 mph). There was a 62% average reduction in the vehicles that utilized the speed ranges above 57 mph for the Approach data and there was a 36% average reduction in the vehicles that utilized the speed ranges above 45 mph for the PC data. The DSM system resulted in a shift in the distribution of speeds from the higher speed bins to the lower speed bins Before and After installation.M.S.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering MS
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Caspersen, Matthew Harold. "The development of the curve of Spee in man." Thesis, University of Iowa, 2005. https://ir.uiowa.edu/etd/5391.
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Kozák, Petr. "Napojení JV obchvatu města Jihlavy-křižovatka silnic I/38 a II/523." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225923.
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This diploma work deals with researching study of transport junction of main road I/38 and major road II/523 and than link-up of the proposed Outer ring road (VMO) and Southeastern by-pass (JVO) routes of region capital Jihlava, district of Jihlava, Vysočina region. Road structure will solve designed staged link-up of aboved mentioned roads according to their construction schedule. The design takes into account current roads and completed stages, with respect to minimum costs. Road structure is situated on Czech-Moravian Highlands. Its terrain is hilly, pondy and composed of agricultural parcels. The main purpose of this design is steady link-up of all considered traffic flows in the given locality.
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Gibb, J. "The cause and cure of periodic flows at transonic speed." Thesis, Cranfield University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233816.
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Bilík, Martin. "Možnosti zjišťování vlivu elektronických stabilizačních systémů podvozku na jízdní dynamiku vozidla." Master's thesis, Vysoké učení technické v Brně. Ústav soudního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-232544.
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This diploma thesis deals with the possibilities of determining the influence of electronic stability systems on the chassis of the vehicle driving dynamics. In the introductory section is made theoretical analysis of road vehicle dynamics. Further description is made of some stabilization systems and situations and how to solve them by using these systems. Chapter 6.2.1 describes the methodology of practical experiment, which can determine influence of the stability system of the vehicle chassis on driving dynamics. The next chapter describes an experiment conducted and interpreted the measured values. The penultimate chapter is a simulation of this experiment using simulation software Virtual Crash. The last chapter is an evaluation of the experiment and compares the results with simulation programs using the same input conditions. The conclusion summarizes the results of this work.
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Warner, Jace Cali. "Device for mechanical plotting of power/speed curves for a D.C. motor." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113495.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (page 23).
The relationships between power, speed, and torque in a direct current motor are often not intuitive to students based on functionality of modern dynamometers. Previous work in a 1998 master's thesis by Peter T. Lee built a device to mechanically demonstrate the torque/speed relationship for engineering students. This thesis expands that work to prototype a modified device to show the power/speed relationship utilizing a mechanical multiplier. Speed and torque output are converted into linear motions along perpendicular axes, and power is output as their product. This thesis summarizes the design and construction of a first prototype of such a mechanical dynamometer device that can be used in teaching demonstrations.
by Jace Cali Warner.
S.B.
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Hattingh, Johannes. "The stability of the curve of spee and the overbite after orthodontic treatment." Diss., Pretoria : [s.n.], 2003. http://upetd.up.ac.za/thesis/available/etd-10132003-123929.
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Liu, X. "Shock/boundary-layer interaction on curved surfaces at transonic speeds." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332125.
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Gong, Huafeng. "Operating speed preditcion [sic] models for horizontal curves on rural four-lane non-freeway highways." Lexington, Ky. : [University of Kentucky Libraries], 2007. http://hdl.handle.net/10225/727.
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Thesis (Ph. D.)--University of Kentucky, 2007.Title from document title page (viewed on March 25, 2008). Document formatted into pages; contains: x, 182 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 136-149).
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Clarke, David Langton. "The effect of manipulating movement-illusion-inducing stimuli on reducing traffic speed on horizontal curves." Scholarly Commons, 1990. https://scholarlycommons.pacific.edu/uop_etds/2937.
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This study assessed the effectiveness of pavement markings painted along the curbs of a two-lane street on reducing driving speed around a curve. Three different types of marking patterns were investigated in a single-case design. The velocity and perceived speed of vehicles passing through a frequently used entrance road on a university campus were measured. Velocity was measured by recording the time it took vehicles to travel 150 ft (45.7 m). To measure perceived speed, volunteer observers rated the speed of videotaped vehicles using a 15 item questionnaire developed for this study. Data were collected only on passenger vehicles during clear weather conditions. The velocity measure indicated that markings, particularly those in a checkerboard pattern, were effective in reducing the number of drivers exceeding 35 mph. This outcome is consistent with the findings from previous studies with similar interventions. The perceived speed measure did not show meaningful trends across phases. Future research with this type of inexpensive intervention and the need to develop a valid and reliable measure of perceived speed, which takes into consideration safety factors in assessing driving behavior, is discussed.
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Fields, William A. "Study of the effects of centrifugal instabilities on flow in a 40 to 1 aspect ratio rectangular curved channel, for Dean numbers from 35 to fully turbulent conditions." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA241742.
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Thesis (M.S. in Mechanical Engineering and Mechanical Engineer)--Naval Postgraduate School, December 1990.Thesis Advisor(s): Ligrani, P. M. "December 1990." Description based on title screen as viewed on March 30, 2010. DTIC Identifier(s): Turbulence, Vortices, Channel Flow, Pressure Measurement, Flow Fields, Laminar Flow, Centrifugal Fields, Aspect Ration, Dean Vortices, Dean Number, Vortex Pairs, Twist (Motion), Radial Velocity, Rectangular Channels, Curvature, Theses. Author(s) subject terms: Dean Vortices, Dean Number, Rectangular Curved Channel. Includes bibliographical references (p. 170-174). Also available in print.
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Bensel, Artur. "Characteristics of the Specific Fuel Consumption for Jet Engines." Aircraft Design and Systems Group (AERO), Department of Automotive and Aeronautical Engineering, Hamburg University of Applied Sciences, 2018. http://d-nb.info/1175791237.
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Purpose of this project is a) the evaluation of the Thrust Specific Fuel Consumption (TSFC) of jet engines in cruise as a function of flight altitude, speed and thrust and b) the determination of the optimum cruise speed for maximum range of jet airplanes based on TSFC characteristics from a). Related to a) a literature review shows different models for the influence of altitude and speed on TSFC. A simple model describing the influence of thrust on TSFC seems not to exist in the literature. Here, openly available data was collected and evaluated. TSFC versus thrust is described by the so-called bucket curve with lowest TSFC at the bucket point at a certain thrust setting. A new simple equation was devised approximating the influence of thrust on TSFC. It was found that the influence of thrust as well as of altitude on TSFC is small and can be neglected in cruise conditions in many cases. However, TSFC is roughly a linear function of speed. This follows already from first principles. Related to b) it was found that the academically taught optimum flight speed (1.316 times minimum drag speed) for maximum range of jet airplanes is inaccurate, because the derivation is based on the unrealistic assumption of TSFC being constant with speed. Taking account of the influence of speed on TSFC and on drag, the optimum flight speed is only about 1.05 to 1.11 the minimum drag speed depending on aircraft weight. The amount of actual engine data was extremely limited in this project and the results will, therefore, only be as accurate as the input data. Results may only have a limited universal validity, because only four jet engine types were analyzed. One of the project's original value is the new simple polynomial function to estimate variations in TSFC from variations in thrust while maintaining constant speed and altitude.
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Powell, Alexander Frank. "An investigation into the relationship between vertical and lateral forces, speed and superelevation in railway curves." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/59440.
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The Gautrain Rapid Rail Link (GRRL) is a rail transit system in South Africa that links Johannesburg and Pretoria, as well as Johannesburg and the O.R. Tambo International Airport. Travelling at speeds of up to 160 km/h, the Gautrain system is the first of its kind on the African continent. This dissertation covers an investigation into the relationship between the vertical and lateral forces, speed and superelevation in a GRRL curve. The research described in this dissertation is based on an experiment which involved running a test train through a curve at various speeds, changing the cant of the curve by tamping and repeating the train runs. The cant was changed due to high wheel wear rates. The curve already had a cant deficiency, and this cant deficiency was subsequently increased by reducing the curve’s cant. Assessing the before and after tamping test data validated the existence of the expected relationships between the vertical and lateral rail forces, the speed and the cant. The change in cant had a minimal effect on the magnitude of the vertical forces, although a transfer of loading between the high and low legs did occur. The theory indicates that the 14 % reduction in cant in this curve given all of the other curve characteristics should have resulted in an increase in the lateral forces. There was however a roughly 50 % reduction in the maximum lateral forces after the cant was reduced that can be explained from a train dynamics point of view. In addition, there was an increase in safety due to a reduced derailment ratio at this curve’s normal operating speed of 85 km/h. It is not unreasonable to presume that a 50 % reduction in the maximum lateral forces could lead to a halving of the wear rate of the rail and wheels in this curve with similar results to be expected in other curves on the rail network.Dissertation (MEng)--University of Pretoria, 2016.
The Chair in Railway Engineering at the University of Pretoria
Civil Engineering
MEng
Unrestricted
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Libichová, Jana. "Studie MÚK silnic R43 s I/43." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225918.
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Aim of this Master´s thesis is the road adjustment and design of new grade separated junction highway R43 and road I/43,of Černá Hora – Svitávka and to design optimal distribution of transport hubs including the design II/150 and III/37429, which should be connected with existing roads.The adjustment of the routes will be designed in the necessary extent with the optimal distribution of transport hubs regarding the best transport and economical solution and with minimal impact on the enviroment.
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Shellabarger, Brian Tebelman. "Experimental studies of high-speed liquid films on flat and curved downward-facing surfaces for IFE applications." Thesis, Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04082004-180413/unrestricted/shellabarger%5fbrian%5ft%5f200312%5fms.pdf.
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Belhadi, M'hamed. "Étude de machines à réluctance variable pour une application de traction électrique : réduction des ondulations de couple et des efforts radiaux." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112185.
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Le mémoire traite de la machine à réluctance variable en proposant d'une manière simultanée et du point de vue conception des solutions à ses deux inconvénients majeurs à savoir les ondulations de couple et les efforts radiaux. Les premières se propagent le long de la chaine de transmission diminuant ainsi le confort des usagers et les deuxièmes sont à l’origine d’une nuisance sonore. Dans une première partie et en s’intéressant à une structure axiale caractérisée par une faible force radiale, un bilan sur cette structure est donc établi. En effet, une configuration à deux stators et un rotor est la plus adéquate pour éventuellement remplacer la machine radiale de référence. Cette structure axiale est comparée à cette machine de référence après avoir établi des règles de passage d’une structure à une autre. Un premier passage est effectué en gardant le même encombrement et un deuxième passage en dimensionnant la machine axiale pour satisfaire le même cahier des charges que la machine radiale. Dans une deuxième partie, le travail s’oriente vers la modification de la structure radiale de la machine de référence et son optimisation. Plusieurs modifications sont proposées dont une structure avec une cale magnétique qui est la plus performante. Des optimisations géométriques à l’aide de l’algorithme génétique sur un point de fonctionnement sont ensuite effectuées pour remédier aux deux problèmes. A la fin, un récapitulatif de plusieurs structures optimisées est proposé pour servir de référence. Le choix de la machine la plus adéquate pourra donc être effectué en faisant un compromis entre la maximisation du couple, la réduction de ses ondulations et la réduction des efforts radiauxThis report deals with switched reluctance motor by offering design solutions to the drawbacks of torque ripples and radial forces in the same time. Torque ripples reduce the user comfort and radial forces are the origin of noise. In the first part, an axial structure characterized by low radial force is analysed. Indeed, an axial configuration with two stators and one rotor is the most appropriate to replace the reference radial machine. Ones the rules of passage from one structure to another are established, the axial structure is then compared to the reference one. A first passage is made by keeping the same volume and a second one by sizing the axial machine with the same specifications as the radial one. In the second part, the work concerns the modification of radial structure of the reference machine and its optimization. Several modifications are proposed including a structure with a magnetic wedge which is the most efficient. Geometric optimization using genetic algorithm are then performed on operating points to remedy the both problems. In the end, several optimized structures are proposed. The choice of the most suitable machine can be done by making a compromise between the torque maximization, reducing its ripples and reducing radial forces
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Paterson, Chay Giles Blair. "Minimal models of invasion and clonal selection in cancer." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/28986.
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One of the defining features of cancer is cell migration: the tendency of malignant cells to become motile and move significant distances through intervening tissue. This is a necessary precondition for metastasis, the ability of cancers to spread, which once underway permits more rapid growth and complicates effective treatment. In addition, the emergence and development of cancer is currently believed to be an evolutionary process, in which the emergence of cancerous cell lines and the subsequent appearance of resistant clones is driven by selection. In this thesis we develop minimal models of the relationship between motility, growth, and evolution of cancer cells. These should be simple enough to be easily understood and analysed, but remain realistic in their biologically relevant assumptions. We utilise simple simulations of a population of individual cells in space to examine how changes in mechanical properties of invasive cells and their surroundings can affect the speed of cell migration. We similarly examine how differences in the speed of migration can affect the growth of tumours. From this we conclude that cells with a higher elastic stiffness experience stronger resistance to their movement through tissue, but this resistance is limited by the elasticity of the surrounding tissue. We also find that the growth rate of large lesions depends weakly on the migration speed of escaping cells, and has stronger and more complex dependencies on the rates of other stochastic processes in the model, namely the rate at which cells transition to being motile and the reverse rate at which cells cease to be motile. To examine how the rates of growth and evolution of an ensemble of cancerous lesions depends on their geometry and underlying fitness landscape, we develop an analytical framework in which the spatial structure is coarse grained and the cancer treated as a continuously growing system with stochastic migration events. Both the fully stochastic realisations of the system and deterministic population transport approaches are studied. Both approaches conclude that the whole ensemble can undergo migration-driven exponential growth regardless of the dependence of size on time of individual lesions, and that the relationship between growth rate and rate of migration is determined by the geometrical constraints of individual lesions. We also find that linear fitness landscapes result in faster-than-exponential growth of the ensemble, and we can determine the expected number of driver mutations present in several important cases of the model. Finally, we study data from a clinical study of the effectiveness of a new low-dose combined chemotherapy. This enables us to test some important hypotheses about the growth rate of pancreatic cancers and the speed with which evolution occurs in reality. We test a moderately successful simple model of the observed growth curves, and use it to infer how frequently drug resistant mutants appear in this clinical trial. We conclude that the main shortcomings of the model are the difficulty of avoiding over-interpretation in the face of noise and small datasets. Despite this, we find that the frequency of resistant mutants is far too high to be explained without resorting to novel mechanisms of cross-resistance to multiple drugs. We outline some speculative explanations and attempt to provide possible experimental tests.
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Chiqueto, Kelly Fernanda Galvão. "Influência da mecânica intrusiva de acentuação e reversão da curva de Spee, no grau de reabsorção radicular." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/25/25134/tde-17082005-143419/.
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O propósito deste estudo foi avaliar a influência da mecânica intrusiva de acentuação e reversão da curva de Spee, no grau de reabsorção radicular dos incisivos superiores e inferiores. Para tanto, selecionou-se uma amostra composta de 60 pacientes, a partir do arquivo da disciplina de Ortodontia da Faculdade de Odontologia de Bauru, apresentando as más oclusões de Classe I e II, 1ª divisão, tratados sem extrações. A amostra foi dividida em dois grupos, com as seguintes características: Grupo 1, constituído por 30 pacientes apresentando uma sobremordida acentuada, tratados com mecânica intrusiva e idade média inicial de 12,8 ± 1,23 anos (mínimo de 10,01 e máximo de 15,32 anos); Grupo 2 constituído por 30 pacientes, apresentando um trespasse vertical normal, tratados sem mecânica intrusiva e idade média de 12,87 ± 1,43 anos (mínimo de 10,02 e máximo de 15,36 anos) ao início do tratamento ortodôntico. Utilizou-se as radiografias periapicais pré e pós-tratamento para avaliar o grau de reabsorção radicular e em seguida, aplicou-se o teste de Mann-Whitney para comparar os grupos. Além disso, verificou-se a correlação entre o grau de reabsorção radicular e a quantidade de movimentação dentária ocorrida durante o tratamento ortodôntico, utilizando o coeficiente de correlação de Spearman. Analisou-se também a influência da morfologia radicular no grau de reabsorção apical, utilizando o teste de Kruskal-Wallis para comparar o grau de reabsorção ocorrido nas diferentes formas radiculares. Os resultados revelaram um maior grau de reabsorção ocorrido no grupo tratado com mecânica intrusiva. O grau de reabsorção radicular demonstrou correlação estatisticamente significante com a quantidade de correção da sobremordida e com a intrusão dos incisivos centrais superiores. Com relação à morfologia radicular, embora as raízes curtas e triangulares tenham apresentado maior reabsorção, não foi encontrada significância estatística na diferença do grau de reabsorção entre as formas radiculares.This study investigated the influence of intrusion mechanics with accentuated and reverse curve of Spee on the degree of root resorption of maxillary and mandibular incisors. A sample of 60 patients with Class I and Class II division 1 malocclusions submitted to treatment without extractions was obtained from the files of the Orthodontic Department of Bauru Dental School. This sample was divided into two groups with the following characteristics: Group 1, comprising 30 patients deep bite, treated with intrusion mechanics, with an initial mean age of 12.80 ± 1.23 years (raging from 10.01 to 15.32 years); Group 2, comprising 30 patients with normal overbite treated without intrusion mechanics, with an initial mean age of 12.87 ± 1.43 years (raging from 10.02 to 15.36 years). Pre- and posttreatment periapical radiographs were used to evaluate the amount of root resorption using scores (0-4), and then the groups were compared using the Mann-Whitney U test. Correlation between the degree of root resorption and amount of tooth movement was tested by the Spearman coefficient. The influence of root morphology on the degree of root resorption was investigated using the Kruskal-Wallis test. The results showed that the deep bite group treated with accentuated and reverse curve of Spee presented more root resorption than the normal overbite group. Changes in overbite and vertical apex displacements had significant correlation. Considering the root morphology, shorter and pointed roots had more resorption, yet with no statistical significance.
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Dearing, Mason Andrew. "Changes in marginal ridge alignment from early childhood to late adulthood in an untreated Caucasian population using the Iowa growth study sample." Thesis, University of Iowa, 2017. https://ir.uiowa.edu/etd/5454.
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Introduction: The purpose of this study was to evaluate the changes in marginal ridge alignment occurring through normal growth and development from early childhood to late adulthood and to examine if any statistical variation exists between males and females.
Methods: Dental casts of 38 subjects (15 females and 23 males) from the Iowa Growth Study were selected. The marginal ridge discrepancy was measured as the absolute value difference between adjacent marginal ridges of 20 interproximal contacts with both the ABO tool (data not shown) and a vertically mounted digital caliper. Upper and lower casts were tripoded to a level plane defined by the most posterior tooth and central point of the most erupted central incisor. A 15 subject calibration was used to measure inter-examiner reliability using the Cronbach’s Alpha and Kappa tests. The independent samples t test was used to examine the correlation of marginal ridge discrepancies between males and females.
Results: Cronbach alpha (p ≤ .001) and Kappa test (p ≤ .01) show excellent inter-rater reliability. The independent sample t test showed no statistical significance, with minimal exception, in marginal ridge discrepancies between males and females matched for age (p > .05). Group 1 showed significantly higher number of marginal ridge discrepancies within ABO range of 0 – 0.5 mm of males and females compared to Group 2.
Conclusion: Based on this study, no statistically significant differences were found in marginal ridge discrepancies between males and females. Also, the magnitude of marginal ridge discrepancies of erupting permanent teeth shows a decrease as an individual proceeds through growth and development and they remain relatively “level” during primary dentition.
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Matova, Tanya. "Refroidissement de fluides complexes : étude des performances de différentes technologies." Phd thesis, Toulouse, INPT, 2012. http://oatao.univ-toulouse.fr/11192/1/matova.pdf.
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Un grand nombre d’industries (chimiques, pharmaceutiques et agroalimentaires) utilisent, produisent ou transforment des fluides complexes. Ce sont des fluides à viscosité élevée, souvent de comportement non-Newtonien. Leur préparation nécessite souvent une étape de chauffe suivie d’une étape de refroidissement. La chauffe est indispensable afin de faciliter la fabrication (réaction chimique et/ou transformation physico-chimique). Le refroidissement, ou encore l’étape de finition, consiste à amener les fluides jusqu’à une température proche de la température ambiante pour aborder l'étape de conditionnement. Le refroidissement est le plus souvent réalisé « in situ » dans la même cuve agitée, équipée d’une double enveloppe (utilisée pour la fabrication), mais des technologies en continu peuvent également être envisagées. Ces travaux de thèse portent sur la mise en place d’une méthodologie de pilotage de la vitesse d’agitation lors du refroidissement de fluides complexes dans des cuves agitées, ainsi que sur la comparaison des performances de la cuve agitée avec celles du mélangeur statique. Deux fluides de travail sont testés : Newtonien et viscoplastique, en régime d’écoulement laminaire et transitoire. Nous déterminons les limites de l’influence de l’agitation sur le transfert thermique, la durée de l’opération et la quantité d’énergie consommée. En premier lieu, le refroidissement est étudié à l’échelle laboratoire (réacteur de 0,6L). Il a été constaté que le changement de la vitesse d’agitation au cours du refroidissement affecte le profil de température. Cela a un impact avantageux sur le coût énergétique et/ ou la durée de refroidissement. Les tendances observées à l’échelle laboratoire sont transposées et validées à l’échelle pilote (réacteur de 60L). Puis deux types de mélangeurs statiques sont étudiés comme technologie en continu. Nous établissons des modèles de perte de charge que nous utilisons dans la détermination de l’énergie dépensée pour le refroidissement. Ensuite nous réalisons une comparaison de leurs performances en fonction des facteurs d’efficacité de transfert thermique et de consommation énergétique. Enfin, une brève analyse comparée est exposée, présentant les divers critères de choix entre la cuve agitée et la technologie en continu.
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Ré, Jean-Philippe. "Variabilité diachronique de la courbe de Spee : exemples d'applications à l'anthropologie funéraire et à l'odontologie clinique." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM5050.
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La courbe de Spee est une courbe située dans un plan para-sagittal. Son étude se fait uniquement au niveau des dents mandibulaires. Il ne s’agit pas d’un « simple » plan d’occlusion dentaire puisque cette courbe intéresse, également de l’os, c’est à dire le condyle mandibulaire et plus particulièrement son bord antérieur. La courbe de Spee est dépendante de l’emplacement du condyle mais également de l’axe de chacune des dents mandibulaires qui participent à sa forme. Son incurvation permet d’aligner les directions des contraintes le long des grands axes dentaires. À partir des valeurs métriques et angulaires mesurées sur des images 3D de mandibules numérisées les objectifs ont été : - de proposer une aide dans la reconstruction de mandibule incomplète et/ou déformée et du plan occlusal absent ou incomplet. - de dégager des principes géométriques simples permettant une optimisation du positionnement des racines artificielles (implants) chez l’Homme actuel. Ainsi les études des axes dentaires mandibulaires, de la position du condyle mandibulaire, de la courbe de Spee, ou encore de différentes mesures mandibulaires, ont permis de dégager un axe de recherche anthropologique et un axe de recherche odontologique Un axe anthropologique Qui amène à la découverte validée de formules de régressions pouvant apporter une aide dans la reconstructions de matériel dentaire, ou osseux incomplet, mandibulaire. Un axe odontologique Qui confirme, et valide cliniquement, que les axes dentaires mandibulaires doivent être orientés le plus favorablement possible en fonction des diverses contraintes occlusalesThe curve of Spee is situated in a para-sagittal plane. His study is done only at the mandibular teeth. It is not a "simple" plan of dental occlusion because this curve interests, also of bone, the mandibular condyle and particularly its front edge. The curve of Spee depends on the condyle location but also on the axis of each of the mandibular teeth which participate in its shape. Its curve aligns the directions of the constraints along major dental axes. From metrics and angular values measured on 3D images of scanned mandibles, the objectives were: - To propose a help in the reconstruction of incomplete and / or deformed mandible and absent or incomplete occlusal plane. - To identify simple geometric principles to optimize the positioning of the artificial roots (implants) in modern Man. So the studies of mandibular dental axes, the position of the mandibular condyle, the curve of Spee, or differents mandibular measures allowed to clear an area of anthropological research and an area of Dental Research An anthropological area Which leads to the validated discovery regression formulas, which can brings help in reconstruction of dental material, or osseous incomplete, mandibular. An odontological area Which confirms and validates clinically, that the mandibular dental axes must be oriented as favorably as possible according to the various occlusal constraints
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Menares, Fernández David Alfonso. "Relación entre la profundidad de la curva de Spee y la angulación de la pared anterior de la cavidad glenoidea, medido a través de TAC 3D Cone Beam." Tesis, Universidad de Chile, 2010. http://repositorio.uchile.cl/handle/2250/133848.
Full textAbstract:
Trabajo de Investigación Requisito para optar al Título de Cirujano DentistaIntroducción: La literatura muestra investigaciones que han relacionado la curva de Spee con la pared anterior de la cavidad glenoidea de manera proporcional, develando escasas conjeturas acerca de su vínculo tanto en su conformación y desarrollo, como en el efecto que puede traer una nivelación de la curva de Spee sobre la ATM durante el tratamiento ortodóncico. Por esta razón, el propósito de este estudio fue investigar si existe relación proporcional directa entre la profundidad de la curva de Spee y la angulación de la pared anterior de la cavidad glenoidea, utilizando para ello la tomografía axial computarizada cone beam. Material y Método: Se estudiaron 110 TAC 3D cone beam de pacientes sin tratamiento de ortodoncia previo o actual, que poseían su fórmula dentaria completa en la zona inferior de al menos un lado. Por medio del programa computacional Galaxis®, de marca Sirona® se midió en los cortes tomográficos la angulación de la pared anterior de la cavidad glenoidea. En la proyección lateral del mismo programa, se midió la profundidad de la curva de Spee, tomando como referencia el borde incisal del incisivo central mandibular y la cúspide distovestibular del segundo molar mandibular. Para esta última medición se utilizó, además, el programa computacional MB-Ruler© versión 4.0. Resultados: En la medición global por lado, se encontró que en el lado derecho había correlación proporcional estadísticamente significativa, mientras que al lado izquierdo no fue estadísticamente significativa. Al realizar el análisis por sexo, se encontró correlación estadísticamente significativa en los hombres en el lado izquierdo, y en las mujeres en el lado derecho. Con respecto a la edad, se encontró correlación estadísticamente significativa en el rango etario de 50 años y más, pero ésta fue solamente en el lado derecho. En los demás rangos etarios no hubo correlación estadísticamente significativa en ningún lado. Conclusiones: No existe una relación proporcional directa entre la profundidad de la curva de Spee y la angulación de la pared anterior de la cavidad glenoidea debido a la gran variabilidad existente en un mismo paciente, no teniendo el sexo ni la edad un efecto significativo sobre dichas variables.
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Dickel, Jacob Allen. "Design Optimization of a Non-Axisymmetric Endwall Contour for a High-Lift Low Pressure Turbine Blade." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1534980581177159.
Full text
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Rocha, Carlos Antonio da. "Medidas de seção de choque de fusão para os sistemas ANTPOT. 12 C + ANTPOT. 63, 65 CU." Universidade de São Paulo, 1987. http://www.teses.usp.br/teses/disponiveis/43/43131/tde-01042014-093351/.
Full textAbstract:
No presente trabalho é apresentado um conjunto de medidas de seção de choque do processo de fusão nuclear nos sistemas ANTPOT. 12 C + ANTPOT. 63, 65 CU, em um intervalo de energia correspondente à 0.91.8 vezes a barreira coulombiana. O método experimental utilizado foi a detecção dos resíduos de evaporação através da técnica de tempo de vôo, acoplado à um defletor eletrostático para separar as partículas provenientes do espalhamento elástico dos produtos de fusão. As vantagens e limitações do método são discutidas em detalhes. As funções de excitação de fusão dos sistemas citados foram analisadas via modelo de penetração de barreira unidimensional , utilizando vários potenciais nucleares. Dessa análise comprovou-se que a secção de choque de fusão é subestimada em energias em torno e abaixo da barreira coulombiana. Nesse sentido foi feito um cálculo, utilizando o código computacional CCFUS, que simula o acoplamento de canais, com a finalidade de descobrir quais canais contribuem para o processo de fusão nuclear em baixas energias. As seções de choque de fusão obtidas foram comparadas com outros sistemas - ANTPOT. 12 C + ANTPOT. 63, 65 CU.- que utilizam os mesmos núcleos-alvo. A comparação revelou que os sistemas ANTPOT. 12 C + ANTPOT. 63, 65 CU possuem o maior aumento de seção de choque de fusão subcoulombiana e esse fato pode estar relacionado à deformação estática do projétil. A comparação das distribuições da velocidade dos resíduos de evaporação para os dois de sistemas revelou um canal intenso para o sistema ANTPOT. 12 C + ANTPOT. 63 CU que não está presente para o outro sistema.In this work we present cross-section measurements for nuclear fusion in the 12C+ 63,65 Cu system, at 12C energy range from 0.9 to 1.8 times the Coulomb barrier. In order to detect and to obtain the mass identification of the evaporation residues following the fusion process, the time of flight method was adopted in conjunction with an eletrostatic deflector capable of separating the evaporation residues from the beam particles. The limitation and advantadges of this method of measurement are discussed. The excitation functions for the above systems were analysed using the unidimensional barrier penetration model with different nuclear potentials. Theoretical fusion cross-section values obtained from this analysis were systematically smaller than our measured values, in the energy region below the Coulomb barrier. In order to discover which channel enhances the fusion cross-section in this region, a coupled channel calculation was performed, with the aid of CCFUS code. The experimental data for the above reactions were compared with the systems 12C+ 63,65 Cu, measured by our group. In this comparison, It was noted that the systems 12C+ 63,65 Cu have greater fusion cross section below the Coulomb barrier. This fact can be related to the static deformation of 12C. The comparison of velocity spectra of the evaporated residues for the two systems shows that 12C+63Cu has a strong reaction channel that was not present in the 12C+ 65Cu system.
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Fujdiak, Radek. "Analýza a optimalizace datové komunikace pro telemetrické systémy v energetice." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-358408.
Full textAbstract:
Telemetry system, Optimisation, Sensoric networks, Smart Grid, Internet of Things, Sensors, Information security, Cryptography, Cryptography algorithms, Cryptosystem, Confidentiality, Integrity, Authentication, Data freshness, Non-Repudiation.
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Avelar, Moran Raul Eduardo. "Safety performance of curve advisory speed signs." Thesis, 2012. http://hdl.handle.net/1957/29376.
Full textAbstract:
Posting advisory speed signs at sharp horizontal curve sites is a practice well established in the United States. The purpose of these signs is to provide the driving public with a safe speed to negotiate such curves; however, the link between these signs and safety has not yet been clearly established.
The first manuscript in this dissertation presents an effort to model safety as it relates to curve advisory speed signs. It proposes a statistical model relating crash frequency at 2-lane rural highways in Oregon to curve advisory speed signs and other influential factors. The Advisory Speed Crash Factor (ASCF) emerges as a sub-model that characterizes the safety effect of advisory speed signs. Results indicate that safety may be compromised if the advisory speed is either excessively prohibitive or excessively permissive.
The second manuscript extends the use of the proposed ASCF to develop the OSU posting method, a new procedure that procures the "optimal" advisory speed derived from the ASCF. A field validation analysis, also presented in this manuscript, verified the meaningfulness of the proposed ASCF sub-model.
The third manuscript outlines another methodology, named 'the Hybrid OSU Posting Method' in an effort to mitigate the well documented variability associated with using the Ball Bank Indicator (BBI). This method determines the advisory speed using the BBI in combination with the ASCF. Though benefits in safety performance and consistency resulted from using the Hybrid OSU method, this method is still outperformed by the computational OSU method.Graduation date: 2012
Access restricted to the OSU Community at author's request from May 25, 2012 - May 25, 2013
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Longa, Patrick. "High-Speed Elliptic Curve and Pairing-Based Cryptography." Thesis, 2011. http://hdl.handle.net/10012/5857.
Full textAbstract:
Elliptic Curve Cryptography (ECC), independently proposed by Miller [Mil86] and Koblitz [Kob87] in mid 80’s, is finding momentum to consolidate its status as the public-key system of choice in a wide range of applications and to further expand this position to settings traditionally occupied by RSA and DL-based systems. The non-existence of known subexponential attacks on this cryptosystem directly translates to shorter keylengths for a given security level and, consequently, has led to implementations with better bandwidth usage, reduced power and memory requirements, and higher speeds. Moreover, the dramatic entry of pairing-based cryptosystems defined on elliptic curves at the beginning of the new millennium has opened the possibility of a plethora of innovative applications, solving in some cases longstanding problems in cryptography. Nevertheless, public-key cryptography (PKC) is still relatively expensive in comparison with its symmetric-key counterpart and it remains an open challenge to reduce further the computing cost of the most time-consuming PKC primitives to guarantee their adoption for secure communication in commercial and Internet-based applications. The latter is especially true for pairing computations. Thus, it is of paramount importance to research methods which permit the efficient realization of Elliptic Curve and Pairing-based Cryptography on the several new platforms and applications.
This thesis deals with efficient methods and explicit formulas for computing elliptic curve scalar multiplication and pairings over fields of large prime characteristic with the objective of enabling the realization of software implementations at very high speeds.
To achieve this main goal in the case of elliptic curves, we accomplish the following tasks: identify the elliptic curve settings with the fastest arithmetic; accelerate the precomputation stage in the scalar multiplication; study number representations and scalar multiplication algorithms for speeding up the evaluation stage; identify most efficient field arithmetic algorithms and optimize them; analyze the architecture of the targeted platforms for maximizing the performance of ECC operations; identify most efficient coordinate systems and optimize explicit formulas; and realize implementations on x86-64 processors with an optimal algorithmic selection among all studied cases.
In the case of pairings, the following tasks are accomplished: accelerate tower and curve arithmetic; identify most efficient tower and field arithmetic algorithms and optimize them; identify the curve setting with the fastest arithmetic and optimize it; identify state-of-the-art techniques for the Miller loop and final exponentiation; and realize an implementation on x86-64 processors with optimal algorithmic selection.
The most outstanding contributions that have been achieved with the methodologies above in this thesis can be summarized as follows:
• Two novel precomputation schemes are introduced and shown to achieve the lowest costs in the literature for different curve forms and scalar multiplication primitives. The detailed cost formulas of the schemes are derived for most relevant scenarios.
• A new methodology based on the operation cost per bit to devise highly optimized and compact multibase algorithms is proposed. Derived multibase chains using bases {2,3} and {2,3,5} are shown to achieve the lowest theoretical costs for scalar multiplication on certain curve forms and for scenarios with and without precomputations. In addition, the zero and nonzero density formulas of the original (width-w) multibase NAF method are derived by using Markov chains. The application of “fractional” windows to the multibase method is described together with the derivation of the corresponding density formulas.
• Incomplete reduction and branchless arithmetic techniques are optimally combined for devising high-performance field arithmetic. Efficient algorithms for “small” modular operations using suitably chosen pseudo-Mersenne primes are carefully analyzed and optimized for incomplete reduction.
• Data dependencies between contiguous field operations are discovered to be a source of performance degradation on x86-64 processors. Three techniques for reducing the number of potential pipeline stalls due to these dependencies are proposed: field arithmetic scheduling, merging of point operations and merging of field operations.
• Explicit formulas for two relevant cases, namely Weierstrass and Twisted Edwards curves over and , are carefully optimized employing incomplete reduction, minimal number of operations and reduced number of data dependencies between contiguous field operations.
• Best algorithms for the field, point and scalar arithmetic, studied or proposed in this thesis, are brought together to realize four high-speed implementations on x86-64 processors at the 128-bit security level. Presented results set new speed records for elliptic curve scalar multiplication and introduce up to 34% of cost reduction in comparison with the best previous results in the literature.
• A generalized lazy reduction technique that enables the elimination of up to 32% of modular reductions in the pairing computation is proposed. Further, a methodology that keeps intermediate results under Montgomery reduction boundaries maximizing operations without carry checks is introduced. Optimized formulas for the popular tower are explicitly stated and a detailed operation count that permits to determine the theoretical cost improvement attainable with the proposed method is carried out for the case of an optimal ate pairing on a Barreto-Naehrig (BN) curve at the 128-bit security level.
• Best algorithms for the different stages of the pairing computation, including the proposed techniques and optimizations, are brought together to realize a high-speed implementation at the 128-bit security level. Presented results on x86-64 processors set new speed records for pairings, introducing up to 34% of cost reduction in comparison with the best published result.
From a general viewpoint, the proposed methods and optimized formulas have a practical impact in the performance of cryptographic protocols based on elliptic curves and pairings in a wide range of applications. In particular, the introduced implementations represent a direct and significant improvement that may be exploited in performance-dominated applications such as high-demand Web servers in which millions of secure transactions need to be generated.
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Hsu, Wei-Chiang, and 徐偉強. "High Speed Scalar Multiplication Architecture forElliptic Curve Cryptosystem." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/22221585338205538062.
Full textAbstract:
碩士國立中山大學
資訊工程學系研究所
99
An important advantage of Elliptic Curve Cryptosystem (ECC) is the shorter key length in public key cryptographic systems. It can provide adequate security when the bit length over than 160 bits. Therefore, it has become a popular system in recent years. Scalar multiplication also called point multiplication is the core operation in ECC. In this thesis, we propose the ECC architectures of two different irreducible polynomial versions that are trinomial in GF(2167) and pentanomial in GF(2163). These architectures are based on Montgomery point multiplication with projective coordinate. We use polynomial basis representation for finite field arithmetic. All adopted multiplication, square and add operations over binary field can be completed within one clock cycle, and the critical path lies on multiplication. In addition, we use Itoh-Tsujii algorithm combined with addition chain, to execute binary inversion through using iterative binary square and multiplication. Because the double and add operations in point multiplication need to run many iterations, the execution time in overall design will be decreased if we can improve this partition. We propose two ways to improve the performance of point multiplication. The first way is Minus Cycle Version. In this version, we reschedule the double and add operations according to point multiplication algorithm. When the clock cycle time (i.e., critical path) of multiplication is longer than that of add and square, this method will be useful in improving performance. The second way is Pipeline Version. It speeds up the multiplication operations by executing them in pipeline, leading to shorter clock cycle time. For the hardware implementation, TSMC 0.13um library is employed and all modules are organized in a hierarchy structure. The implementation result shows that the proposed 167-bit Minus Cycle Version requires 156.4K gates, and the execution time of point multiplication is 2.34us and the maximum speed is 591.7Mhz. Moreover, we compare the Area x Time (AT) value of proposed architectures with other relative work. The results exhibit that proposed 167-bit Minus Cycle Version is the best one and it can save up to 38% A T value than traditional one.
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"A novel high speed GF (2173) elliptic curve crypto-processor." 2003. http://library.cuhk.edu.hk/record=b5891648.
Full textAbstract:
Leung Pak Keung.Thesis (M.Phil.)--Chinese University of Hong Kong, 2003.
Includes bibliographical references (leaves 69-70).
Abstracts in English and Chinese.
Chapter Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Introduction to Elliptic Curve Crypto-processor --- p.1
Chapter 1.2 --- Aims --- p.2
Chapter 1.3 --- Contributions --- p.2
Chapter 1.4 --- Thesis Outline --- p.3
Chapter Chapter 2 --- Cryptography --- p.5
Chapter 2.1 --- Introduction to Cryptography --- p.5
Chapter 2.2 --- Public-key Cryptosystems --- p.6
Chapter 2.3 --- Secret-key Cryptosystems --- p.9
Chapter 2.4 --- Discrete Logarithm Problem --- p.9
Chapter 2.5 --- Comparison between ECC and RSA --- p.10
Chapter 2.6 --- Summary --- p.13
Chapter Chapter 3 --- Mathematical Background in Number Systems --- p.14
Chapter 3.1 --- Introduction to Number Systems --- p.14
Chapter 3.2 --- "Groups, Rings and Fields" --- p.14
Chapter 3.3 --- Finite Fields --- p.15
Chapter 3.4 --- Modular Arithmetic --- p.16
Chapter 3.5 --- Optimal Normal Basis --- p.16
Chapter 3.5.1 --- What is a Normal Basis? --- p.17
Chapter 3.5.2 --- Addition --- p.17
Chapter 3.5.3 --- Squaring --- p.18
Chapter 3.5.4 --- Multiplication --- p.19
Chapter 3.5.5 --- Optimal Normal Basis --- p.19
Chapter 3.5.6 --- Generation of the Lambda Matrix --- p.20
Chapter 3.5.7 --- Inversion --- p.22
Chapter 3.6 --- Summary --- p.24
Chapter Chapter 4 --- Introduction to Elliptic Curve Mathematics --- p.26
Chapter 4.1 --- Introduction --- p.26
Chapter 4.2 --- Mathematical Background of Elliptic Curves --- p.26
Chapter 4.3 --- Elliptic Curve over Real Number System --- p.27
Chapter 4.3.1 --- Order of the Elliptic Curves --- p.28
Chapter 4.3.2 --- Negation of Point P --- p.28
Chapter 4.3.3 --- Point at Infinity --- p.28
Chapter 4.3.4 --- Elliptic Curve Addition --- p.29
Chapter 4.3.5 --- Elliptic Curve Doubling --- p.30
Chapter 4.3.6 --- Equations of Curve Addition and Curve Doubling --- p.31
Chapter 4.4 --- Elliptic Curve over Finite Fields Number System --- p.32
Chapter 4.4.1 --- Elliptic Curve Operations in Optimal Normal Basis Number System --- p.32
Chapter 4.4.2 --- Elliptic Curve Operations in Projective Coordinates --- p.33
Chapter 4.4.3 --- Elliptic Curve Equations in Projective Coordinates --- p.34
Chapter 4.5 --- Curve Multiplication --- p.36
Chapter 4.6 --- Elliptic Curve Discrete Logarithm Problem --- p.37
Chapter 4.7 --- Public-key Cryptography in Elliptic Curve Cryptosystem --- p.38
Chapter 4.8 --- Diffie-Hellman Key Exchange in Elliptic Curve Cryptosystem --- p.38
Chapter 4.9 --- Summary --- p.39
Chapter Chapter 5 --- Design Architecture --- p.40
Chapter 5.1 --- Introduction --- p.40
Chapter 5.2 --- Criteria for the Low Power System Design --- p.40
Chapter 5.3 --- Simplification in ONB Curve Addition Equations over Projective Coordinates --- p.41
Chapter 5.4 --- Finite Field Adder Architecture --- p.43
Chapter 5.5 --- Finite Field Squaring Architecture --- p.43
Chapter 5.6 --- Finite Field Multiplier Architecture --- p.44
Chapter 5.7 --- 3-way Parallel Finite Field Multiplier --- p.46
Chapter 5.8 --- Finite Field Arithmetic Logic Unit --- p.47
Chapter 5.9 --- Elliptic Curve Crypto-processor Control Unit --- p.50
Chapter 5.10 --- Register Unit --- p.52
Chapter 5.11 --- Summary --- p.53
Chapter Chapter 6 --- Specifications and Communication Protocol of the IC --- p.54
Chapter 6.1 --- Introduction --- p.54
Chapter 6.2 --- Specifications --- p.54
Chapter 6.3 --- Communication Protocol --- p.57
Chapter Chapter 7 --- Results --- p.59
Chapter 7.1 --- Introduction --- p.59
Chapter 7.2 --- Results of the Public-key Cryptography --- p.59
Chapter 7.3 --- Results of the Session-key Cryptography --- p.62
Chapter 7.4 --- Comparison with the Existing Crypto-processor --- p.65
Chapter 7.5 --- Power Consumption --- p.66
Chapter Chapter 8 --- Conclusion --- p.68
Bibliography --- p.69
Appendix --- p.71
173-bit Type II ONB Multiplication Table --- p.71
Layout View of the Elliptic Curve Crypto-processor --- p.76
Schematics of the Elliptic Curve Crypto-processor --- p.77
Schematics of the System Level Design --- p.78
Schematics of the I/O Control Interface --- p.79
Schematics of the Curve Multiplication Module --- p.80
Schematics of the Curve Addition Module --- p.81
Schematics of the Curve Doubling Module --- p.82
Schematics of the Field Inversion Module --- p.83
Schematics of the Register Unit --- p.84
Schematics of the Datapath --- p.85
Schematics of the Finite Field ALU --- p.86
Schematics of the 3-way Parallel Multiplier --- p.87
Schematics of the Multiplier Elements --- p.88
Schematics of the Field Adder --- p.89
Schematics of Demultiplexer --- p.90
Schematics of the Control of the Demultiplexer --- p.91
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Sabhanayagam, Akshaey. "Impact of S-Curve on Speed in a Modern Roundabout." 2018. https://scholarworks.umass.edu/masters_theses_2/664.
Full textAbstract:
According to the US Department of Transportation, around 20 people die on a daily basis in a signalized intersection, with most of these resulting from angle or head-on collisions. The US-DoT’s Federal Highway Administration (FHWA) has identified modern roundabout intersections to be substantially safer than signalized intersections, due in part to the reduction in conflict points from 32 in a traditional signalized intersection to 8 in a modern roundabout. Despite the increased adoption of modern roundabouts across the US, there are a number of specific design elements for which the direct impact they have on operational and safety related performance of the roundabout remains unknown. To be specific, there is currently no conclusive research on the direct effects related to the introduction of a reverse curve (S-curve) on the approach to a roundabout. Moreover, what are the impacts of S-curves of varying geometries on the approach to a roundabout? This research employed a series of microsimulation-based analyses to investigate the speed related impacts related to the introduction to S-curves on the entry to a roundabout.
An existing roundabout, in Amherst, MA, USA was used as a case study for this experiment. The data at each approach of the roundabout was collected by a static camera strategically placed to attain both the pedestrian and vehicle count during peak traffic hours. The data was manually reviewed to determine the upstream and downstream vehicle counts.
The dimensions and angles of the existing roundabout were measured from Google earth and the image was extracted to AutoCaD Civil 3D. Since the objective is to check whether S-curves near an approach have a significant impact in speed, the deflection angle of the roundabout was not altered. The turning radius and angle at the approach was cross verified by measuring it on site. The existing roundabout was considered as the base model. The four approaches of the roundabout have different entry angles and radii. The revised models were drafted by strategically placing the S-curve at each approach and by steadily increasing their deflection angle and approach radius.
The base and revised models cases were initially modelled, after which the conventional linear approach was modified to an S-curve and evaluated. Field data from the locations were to and calibrate microsimulation models on AIMSUN. The resulting trajectory data was analyzed for both the base case as well as three levels of experimental S-curves (ranging from 30 to 60 degrees) on each roundabout approach (16 total). The results provide evidence to suggest that a significant reduction in speed can be realized with a minimal amount of the reverse curvature on the roundabout approach. The trajectory output files were then imported into the Surrogate Safety Assessment Model (SSAM) to determine the number and type of conflicts experienced at each approach under each scenario evaluated in AIMSUN.
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Chen, Jun-Hong, and 陳俊宏. "Development of High-Speed VLSI Architecture of Elliptic Curve Cryptosystem." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/24651612198611343778.
Full textAbstract:
碩士國立雲林科技大學
電子與資訊工程研究所碩士班
91
With the explosion of electronic data communication and computer network, how to ensure the security of transmitted data has become an important topic in current research. In this thesis, we focus on the hardware implementation of the Elliptic Curve Cryptography (ECC). By detailed survey and analysis of the existing work on ECC, the aim of this thesis is to speed up the operations of encryption and decryption in ECC under limited hardware resources. Since the inversion operation will dominate the overall performance of ECC, this thesis first presented an efficient inversion algorithm based on the Montgomery inversion algorithm. Compared with the results of previous work, our development can save up to 7.9% in hardware requirement and 97.6% in the critical path delay. To further decrease the computation time in ECC, this thesis applied the modified Booth encoding in conjunction with the scheduling and interleaving schemes to reduce the number of 1’s in the operands and to remove the idle time of hardware resources. In this manner, we can reduce the number of additions and relax the data dependency on those arithmetic operations performed in ECC encryption/decryption so as to make the hardware resource sharing become possible. In consequence, by increasing the hardware utilization, we can achieve the performance of radix-4 arithmetic by only employing the radix-2 hardware realization. Finally, the developed architecture has the properties of modular design, regular structure and expandable feature; therefore, it is very suitable for VLSI implementation.
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Guan, Yu-Syuan, and 官郁軒. "Speed Curve Planning and Human Machine Interface Development of a Delta Robot." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/b9t85a.
Full textAbstract:
碩士國立臺灣海洋大學
機械與機電工程學系
106
This study first developed a Delta Robot animation simulation software using MATLAB. This software's friendly interface allows users to adjust key parameters and simulate them with animations. In addition to the equipment and components that can be purchased directly, the remaining parts are designed using SolidWorks drawing software. After confirming that the dimensions and movement conditions are correct, they are outsourced and assembled into a physical Delta Robot. In the control system part, a multi-axis motion control card is used to drive three servo motors so that the end effector can move smoothly in a trapezoidal or S-curve acceleration/deceleration mode in real time. Next, we use Visual Studio developed by Microsoft to write a C# program and design a human-machine interface to control the motion of the Delta Robot. This human-machine interface can also display real-time information and motion status of the Delta Robot.
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Lin, Zheng-Ting, and 林政霆. "Study of Path Planning Integrating S-Curve Speed Control for Robot Manipulators." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/97724394365977523648.
Full textAbstract:
碩士國立臺灣科技大學
自動化及控制研究所
104
A parallel robot is one kind of robot that plays an important role, and also the Delta robot is widely used in industry nowadays. It not only presents the background of the Delta robot including its history and development in this thesis but also explains the industrial applications, the current design and the future trend of Delta robot. Then it proposes nine differences between the parallel robot and the series robot. Ultimately, the kinematics of the Delta robot, including the direct and inverse kinematics, the workspace, and the singularity analysis, are systematically presented in detailed. This study mainly focuses on the trajectory planning for the Delta robot, which includes the path planning in the three-dimensional space and the motion profile design of the end-effector. The path planning provides straight lines, circles, parabolic curves, Bézier curves, Cubic-spline curves, and B-spline curves. The motion profile design provides the trapezoid speed control and the S-curve speed control. These paths and the speed control methods are usually applied to the industry. When the path is specified, the Simpson's rule and the bisection method are applied to determine the coordinate of the end-effector at any specific time, and then the angles of the active joints can be evaluated based on the inverse kinematics.