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Optimisation of traffic steering for heterogeneous mobile networksFrei, Sandra January 2015 (has links)
Mobile networks have changed from circuit switched to IP-based mobile wireless packet switched networks. This paradigm shift led to new possibilities and challenges. The development of new capabilities based on IP-based networks is ongoing and raises new problems that have to be tackled, for example, the heterogeneity of current radio access networks and the wide range of data rates, coupled with user requirements and behaviour. A typical example of this shift is the nature of traffic, which is currently mostly data-based; further, forecasts based on market and usage trends indicate a data traffic increase of nearly 11 times between 2013 and 2018. The majority of this data traffic is predicted to be multimedia traffic, such as video streaming and live video streaming combined with voice traffic, all prone to delay, jitter, and packet loss and demanding high data rates and a high Quality of Service (QoS) to enable the provision of valuable service to the end-user. While the demands on the network are increasing, the end-user devices become more mobile and end-user demand for the capability of being always on, anytime and anywhere. The combination of end-user devices mobility, the required services, and the significant traffic loads generated by all the end-users leads to a pressing demand for adequate measures to enable the fulfilment of these requirements. The aim of this research is to propose an architecture which provides smart, intelligent and per end-user device individualised traffic steering for heterogeneous mobile networks to cope with the traffic volume and to fulfil the new requirements on QoS, mobility, and real-time capabilities. The proposed architecture provides traffic steering mechanisms based on individual context data per end-user device enabling the generation of individual commands and recommendations. In order to provide valuable services for the end-user, the commands and recommendations are distributed to the end-user devices in real-time. The proposed architecture does not require any proprietary protocols to facilitate its integration into the existing network infrastructure of a mobile network operator. The proposed architecture has been evaluated through a number of use cases. A proof-of-concept of the proposed architecture, including its core functionality, was implemented using the ns-3 network simulator. The simulation results have shown that the proposed architecture achieves improvements for traffic steering including traffic offload and handover. Further use cases have demonstrated that it is possible to achieve benefits in multiple other areas, such as for example improving the energy efficiency, improving frequency interference management, and providing additional or more accurate data to 3rd party to improve their services.
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The steering relationship between the first and second axles of a 6x6 off-road military vehicleVan Eeden, Carl-Johann 25 October 2007 (has links)
The steering arrangement of a 6x6 off-road military vehicle was investigated, with the aim to determine if a variable steering ratio between the first and second steering axle of the vehicle will make an improvement in the steady and transient state handling of the vehicle. Low speed manoeuvring was evaluated, comparing the vehicle steering geometry with Ackerman geometry. For steady state handling, a bicycle model was developed, and constant radius simulations at various track radii, vehicle speeds and steering ratios (ratio between the first and second steering axle) was performed. For transient dynamic simulations, a mathematical model was developed that included a simple driver model to steer the vehicle through a single lane change, again at various speeds and steering ratios. The vehicle was instrumented, and actual constant radii tests, as well as single lane change tests were performed. The measurements enabled the comparison of simulated and measured results. Although basic mathematical models were used, acceptable correlation was obtained for both steady state and transient dynamic behaviour. The results indicated that for this specific vehicle geometry, where the centre of mass is above the second axle, no marked improvement would be obtained by implementing a variable ratio steering system. The mathematical model was changed to simulate a vehicle with longer wheelbase and different centre of mass. With the new geometry, theoretical slip angles (and therefore tire wear) reductions were more noticeable It was concluded that a variable ratio system between the front and second axle would not be an economically viable improvement for this vehicle, since the improvement achieved will not warrant the additional cost and complexity added to the vehicle. / Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / MEng / unrestricted
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One Pass Packet Steering (OPPS) for Multi-Subscriber Software Defined Networking EnvironmentsChukwu, Julian January 2017 (has links)
In this thesis, we address the problem of service function chaining in a network. Currently, problems of chaining services in a network (i.e. service function chaining) can be broadly categorised into middlebox placement in a network and packet steering through middleboxes.
In this work, we present a packet steering approach - One Pass Packet Steering (OPPS) - for use in multi-subscriber environments, with the aim that subscribers having similar policy chain composition should experience the same network performance. We develop and show algorithms with a proof of concept implementation using emulations performed with Mininet. We identify challenges and examine how OPPS could benefit from the Software Defined Data Center architecture to overcome these challenges.
Our results show that, given a fixed topology and different sets of policy chains containing the same middleboxes, the end-to-end delay and throughput performance of subscribers using similar policy chains remains approximately the same. Also, we show how OPPS can use a smaller number of middleboxes and yet, achieve the same hop count as that of a reference model described in a previous work as ideal, without violating the subscribers' policy chains.
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Manufacturing Three-dimensional Carbon-fibre Preforms for Aerospace CompositesDrivas, Thanos January 2014 (has links)
Carbon fibre reinforced polymer matrix composites (CF PMCs) are increasingly used in state-of-the-art aerospace applications. Aerospace manufacturers favour components made of CF PMCs over those made of traditional metallic alloys because of their light weight and corrosion resistance, which lead to significant improvements in fuel consump- tion, increased payload capability, and reduced maintenance and inspection costs. How- ever, manufacturing of CF PMC components is performed differently than traditional material in all stages – design, prototyping and production – and therefore, many com- mercial manufacturers have only recently begun producing components with CF PMCs.
The first half of this thesis was written as a contribution to the CRIAQ COMP-501 project, which focusses on investigating the cost-effective procurement of airframe com- ponents that are manufactured from final-thickness, net-shaped, and through-thickness reinforced CF preforms. Reinforcement preforms were assembled from commercial 2D woven fabric using stacks of various configurations of structural through-thickness CF stitch. The contribution herein provides the results obtained from investigations into the mechanical behaviour of the relevant reinforcements, when subjected to pre-infusion op- erations typical to RTM VARTM; mechanical behaviour in compaction, shear (draping) and bending (forming).
The second half of this thesis presents the major developments which were made to an alternative process for producing thick 3D preforms with great versatility, a process originally proposed as a candidate for supplying preforms to the COMP-501 project. This process interfaces a proprietary kinematic drape optimization (CAD) software with proprietary automated dry fibre placement assembly (CAM) machinery to produce vari- able or final-thickness reinforcements which are highly-drapable and can lay steered tow yarns.
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Dědické řízení v České republice / Steering gear of inheritance in Czech RepublicCharvátová, Karolína January 2014 (has links)
The theme of dissertation is "Inheritance and steering gear of inheritance in Czech Republic" because I widen the original theme of procedural law to material law - inheritance, according to New Civil Code (NOZ) which brought to Czech legal order many changes, also in the area of inheritance in Czech legislation. The thesis also analyses the changes which brought Zákon o zvláštních řízeních soudních. Dissertation then compares the new and the old legislation, highlights its pluses and minuses and also resolves if the new legislation is better the the old legislation and where are these changes obvious. This thesis should be general knowledge of changes in area of inheritance and steering gear according to NOZ, not at all detailed processing of institutes of inheritance law. Practical part of the thesis analyses judicature and three concrete testaments.
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Efeitos do envelhecimento do motorista e da luminosidade do ambiente sobre o tempo de reação para frenagem durante a condução simulada de automóvel /Esteves, Tânia Silvia Tadini January 2019 (has links)
Orientador: Sérgio Tosi Rodrigues / Resumo: O envelhecimento populacional está associado a profundas mudanças sociais, econômicas e culturais. O comprometimento perceptual e cognitivo resultante do envelhecimento pode provocar falhas durante o desempenho da condução de automóvel. Os fatores humanos desempenham um papel fundamental nos riscos de acidentes de trânsito. O objetivo do presente estudo foi determinar os efeitos do envelhecimento do motorista e da luminosidade do ambiente sobre o tempo de reação da frenagem, durante a condução simulada de automóveis. Quinze motoristas adultos jovens e quinze motoristas idosos realizaram uma tarefa de condução na qual foram mensurados os tempos de reação envolvidos na frenagem (retirada do pé do pedal do acelerador e acionamento do pedal de freio) em um simulador de direção de um automóvel. A tarefa dos participantes foi seguir por um percurso de 5 km um carro à frente, que freava bruscamente acendendo a luz vermelha traseiro do carro, em duas condições: uma com luminosidade diurna e outra com luminosidade noturna. Um pré-teste de tempo de reação simples utilizando os pedais de acelerador e freio, fora do cenário simulado da condução, foi realizado como situação controle. Os dados da condução simulada foram submetidos à análise de variância do grupo (adultos, idosos) por luminosidade (diurna, noturna), com medidas repetidas no segundo fator. Nas condições de condução do veículo, os idosos mostraram tempo de reação maior tanto para retirar o pé do acelerador quando para acionar... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Population aging is associated with profound social, economic and cultural changes. The perceptual and cognitive impairment resulting from aging can cause failures during car driving performance. Human factors play a key role in the risks of traffic accidents. The aim of this study was to determine the effects of driver’s aging and ambient luminosity on the braking reaction time during simulated car driving. Fifteen young adult drivers and fifteen elderly drivers performed a driving task in which the reaction times involved in braking (removing the foot from gas pedal and pressing brake pedal) were measured in a car driving simulator. Participants’ task was to follow a car in front of them during a 5 km path, which braked abruptly with the rear red light turning on, in two conditions: day and night light conditions. A simple reaction time pre-test utilizing gas and brake pedals, out of the simulated driving scenario, was conducted as a control situation. Data from driving conditions were submitted to a group (adults, elderly) by luminosity (day, night) analysis of variance, with repeated measures in the second factor. During driving conditions, the elderly group showed greater reaction time to release the gas pedal and to press the brake pedal; the same occurred to the total reaction time in the total reaction time. Interestingly, reaction times during day light luminosity were greater than those during night luminosity for gas pedal and total reaction times. Results are disc... (Complete abstract click electronic access below) / Mestre
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Skolchefen i styrkedjan : Mellan politiken och professionen / The superintendent in the steering chain : Between politics and the professionAndersson, Marika January 2021 (has links)
Syftet med föreliggande studie är att undersöka skolchefens roll i skolans styrkedja, där hen befinner sig i både det politiska verksamhetssystemet och i det professionella. Samtidigt som hen befinner sig i gränssnittet mellan de båda (Svedberg, 2014; Nihlfors, 2003). Hur påverkar det faktumet skolchefens roll? Hur navigeras det mellan dessa båda system, där det dessutom finns olika lagar som på olika sätt styr skolans arbete och som också kan vara motstridiga? De frågor som ställs är följande: · Hur förhåller sig skolchefen till sin roll mellan två olika verksamhetssystem: det politiska och det professionella? · Vilka motsättningar uppstår i, och mellan, det politiska och det professionella verksamhetssystemet? Studien utgår från ett verksamhetsteoretiskt perspektiv där politiken och professionen utgör varsitt verksamhetssystem. I det politiska verksamhetssystemet är objektet ekonomi, och budget i balans det resultat som ska uppnås. I det professionella systemet är objektet eleven och målet elevens måluppfyllelse. Den metod som används är enfallsstudien och insamling av empirisk data sker med observationer av nämndmöten och möten i förvaltningsledningen, intervjuer med skolchef och dokumentanalys. I analysen av resultatet används verksamhetsteori som analysverktyg. Resultatet visar på målkonflikter som uppstår både i respektive verksamhetssystem och mellan dem. Skolchefen i studien visar en medvetenhet om att hen i sitt uppdrag har att förhålla sig till de konflikter det innebär att befinna sig mellan politik och profession, ekonomi och elevernas resultat. Studiens resultat bidrar till tidigare forskning genom att identifiera målkonflikter som uppstår, men även genom att visa på ett förslag på hur skolchefen, som är subjektet i de två systemen, kan spela en nyckelroll. / The purpose of this study is to investigate the role of the superintendent within the school's steering chain, where he is in both the political and the professional activity systems, while at the same time he is in between the two (Svedberg, 2014; Nihlfors, 2003). How does that fact affect the superintendent’s role? How does he navigate between these two systems, where there are different laws that in different ways govern the school's work, which can also be contradictory? The questions asked are the following: · How does the superintendent relate to his role between two different activity systems: the political and the professional? · What contradictions arise in, and between, the political and the professional activity systems? The study is based on a activity theory perspective where politics and the profession each constitute an activity system. In the political activity system the object is economy, and the result to be achieved is a balanced budget. In the professional system the object is the student, and the student’s goal fulfillment is the goal. The method used is the single case study, and the collection of empirical data is done through observations of board meetings and meetings of the administrative management, interviews with the superintendent, and document analysis. In the analysis of the result, activity theory is used as an analysis tool. The results show that conflicts arise both within the respective activity systems and between them. The superintendent in the study shows awareness that he, in his assignment, has to relate to the conflicts it entails to be between politics and profession, economics and the students’ results. The results of the study add to previous research by identifying conflicts, but also by giving a suggestion on how the superintendent, who is the subject of the two systems, can play a key role.
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Návrh a realizace odometrických snímačů pro mobilní robot s Ackermannovým řízením / Design and realization of odometry sensors for mobile robot with Ackermann steeringPorteš, Petr January 2017 (has links)
Aim of this thesis is to design and construct odometric sensors for a mobile robot with Ackermann steering Bender 2 and to design a mathematical model which would evaluate the the trajectory of the robot using measured data of these sensors. The first part summarizes theoretical knowledge, while the second, the practical part, describes the design of the front axle, the design and the operating software of the front encoders and the odometric models. The last part deals with the processing and evaluation of the measured data.
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Úprava přední vidlice motocyklu / Modification of the front fork of the motorcycleSmolka, Josef January 2017 (has links)
The aim of this thesis is to investigate the force loading of the front telescopic fork girder of the motorcycle and its impact on the structure of the girders. The force effect in fork storage is solved by a mathematical model in Adams View based on calculated and experimentally determined parameters. Managed to gather a series of data and parameters of the Triumph Daytona 955i. The created model achieves high accuracy in terms of motorcycle kinematics. The benefit of this work is to get an overview of the forces acting in the suspension of the front wheel of the motorcycle.
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Konstrukce jednoúčelového stroje na opracování polyuretanových odlitků / Design of single-purpose machine for machining polyurethane castingsSýkora, Petr January 2021 (has links)
The aim of this diploma thesis is to design a single-purpose machine for machining steering wheel lever from PUR. The problem with the current state was the need of manpower for machine a large number of levers. The automated machining process eliminates the problem. The result of the work is a detailed 3D model of a single-purpose machine created in the Onshape program, drawing documentation of several parts of the equipment, economic evaluation and risk analysis of the machine. The conclusion of the thesis contains an evaluation of the whole project.
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