Submitted by PPG Ci?ncia da Computa??o (ppgcc@pucrs.br) on 2018-04-03T14:30:24Z No. of bitstreams: 1 MARCELO_MELO_LINCK_DIS.pdf: 4153250 bytes, checksum: 821a8f1e65f49c1b24a0b69b4f6e7f94 (MD5) / Approved for entry into archive by Tatiana Lopes (tatiana.lopes@pucrs.br) on 2018-04-12T21:09:45Z (GMT) No. of bitstreams: 1 MARCELO_MELO_LINCK_DIS.pdf: 4153250 bytes, checksum: 821a8f1e65f49c1b24a0b69b4f6e7f94 (MD5) / Made available in DSpace on 2018-04-12T21:23:08Z (GMT). No. of bitstreams: 1 MARCELO_MELO_LINCK_DIS.pdf: 4153250 bytes, checksum: 821a8f1e65f49c1b24a0b69b4f6e7f94 (MD5) Previous issue date: 2018-03-22 / Acessos simult?neos gerados por m?ltiplos clientes para um ?nico dispositivo de mem?ria em um Sistema-em-Chip (SoC) imp?e desafios que requerem aten??o extra devido ao gargalo gerado na performance. Considerando estes clientes como processadores, este problema torna-se mais evidente, pois a taxa de crescimento de velocidade para processadores excede a de dispositivos de mem?ria, criando uma lacuna de desempenho. Neste cen?rio, estrat?gias de controle de mem?ria s?o necess?rias para aumentar o desempenho do sistema. Estudos provam que a comunica??o com a mem?ria ? a maior causa de atrasos durante a execu??o de programas em processadores. Portanto, a maior contribui??o deste trabalho ? a implementa??o de uma arquitetura de controlador de mem?ria composta por dois n?veis: prioridade e mem?ria. O n?vel de prioridade ? respons?vel por interagir com os clientes e escalonar requisi??es de mem?ria de acordo com um algoritmo de prioridade fixa. O n?vel de mem?ria ? respons?vel por reordenar as requisi??es e garantir o isolamento de acesso ? mem?ria para clientes de alta prioridade. O principal objetivo deste trabalho ? apresentar um modelo que reduza as lat?ncias de acesso ? mem?ria para clientes de alta prioridade em um sistema altamente escal?vel. Os experimentos neste trabalho foram realizados atrav?s de uma simula??o comportamental da estrutura proposta utilizando um programa de simula??o. A an?lise dos resultados ? dividida em quatro partes: an?lise de lat?ncia, an?lise de row-hit, an?lise de tempo de execu??o e an?lise de escalabilidade. / Simultaneous accesses generated by memory clients in a System-on-Chip (SoC) to a single memory device impose challenges that require extra attention due to the performance bottleneck created. When considering these clients as processors, this issue becomes more evident, because the growth rate in speed for processors exceeds the same rate for memory devices, creating a performance gap. In this scenario, memory-controlling strategies are necessary to improve system performances. Studies have proven that the main cause of processor execution lagging is the memory communication. Therefore, the main contribution of this work is the implementation of a memory-controlling architecture composed of two levels: priority and memory. The priority level is responsible for interfacing with clients and scheduling memory requests according to a fixed-priority algorithm. The memory level is responsible for reordering requests and guaranteeing memory access isolation to high-priority clients. The main objective of this work is to provide latency reductions to high-priority clients in a scalable system. Experiments in this work have been conducted considering the behavioral simulation of the proposed architecture through a software simulator. The evaluation of the proposed work is divided into four parts: latency evaluation, row-hit evaluation, runtime evaluation and scalability evaluation.

The generation of wind energy deliberately becomes a significant part of generated electrical power in developed nations. Factors like fluctuation in natural wind speed and the use of power electronics present issues related power quality in wind turbine application. Following to the fact that there have been remarkable increase of wind energy in the electrical energy production worldwide, the effect on power quality and power system stability caused by wind power is considered significant, and hence the evaluation of this effect is crucial and obligatory. In order to examine and evaluate the characteristics of power quality of grid-integration of wind power in a persistent and authentic manner, several guidelines were introduced and established. One of the widely used guideline to define power quality of wind turbine is IEC standard 61400-21. Moreover, power system operator demands wind turbines to tolerate a certain voltage dip in some countries. The wind turbines concepts such as doubly-fed induction generator wind turbine and the direct driven wind turbine wind turbine with a permanent magnet synchronous generator are considered as the most promising concepts among other wind turbine types since they can operate in wide range of wind speed. The major goal of this PhD work is to examine the power quality character aspects of these wind turbine concepts. The power quality problems were calculated according to that devised by IEC- 61400-21 and then compared afterwards. The research includes the evaluation of the following power quality characteristics: voltage dip response, current harmonics distortion, control of active and reactive power and voltage flicker. Besides the IEC-standard 61400-21, the study also looks into the short-circuit current and fault-ride through with specifications provided by some grid codes, as power system stability is greatly influenced by these aspects. In order to achieve the research's goal, a reliable dynamic model of wind turbine system and control are required. Thus a complete model for both wind turbines systems was developed in PSCAD/EMTDC simulation-program which is the fanatical power system analysis tool, which can achieve a complete simulation of the system dynamic behaviour from the wind turbine. Two controllers are adopted for wind turbine system, converter control and pitch angle control. The converter controlled by a vector control in order to regulate the active and the reactive power whereas the pitch control scheme is put to function to limit the aerodynamic power in high wind speed. The ability of providing adequate state steady and dynamic performances are what wind turbine assures, as examined by simulation results, and via this, problems related to power quality caused by integrating wind turbines to the grid can be studied by wind turbine model.

Commercial Buildings and complexes are no longer just national heat and power network energy loads, but they are becoming part of a smarter grid by including their own dedicated local heat and power generation. They do this by utilising both heat and power networks/micro-grids. A building integrated approach of Combined Heat and Power (CHP) generation with photovoltaic power generation (PV) abbreviated as CHPV is emerging as a complementary energy supply solution to conventional (i.e. national grid based) gas and electricity grid supplies in the design of sustainable commercial buildings and communities. The merits for the building user/owner of this approach are: to reduce life time energy running costs; reduce carbon emissions to contribute to UK’s 2020/2030 climate change targets; and provide a more flexible and controllable local energy system to act as a dynamic supply and/or load to the central grid infrastructure. The energy efficiency and carbon dioxide (CO2) reductions achievable by CHP systems are well documented. The merits claimed by these solutions are predicated on the ability of these systems being able to satisfy: perfect matching of heat and power supply and demand; ability at all times to maintain high quality power supply; and to be able to operate with these constraints in a highly dynamic and unpredictable heat and power demand situation. Any circumstance resulting in failure to guarantee power quality or matching of supply and demand will result in a degradation of the achievable energy efficiency and CO2 reduction. CHP based local energy systems cannot rely on large scale diversity of demand to create a relatively easy approach to supply and demand matching (i.e. as in the case of large centralised power grid infrastructures). The diversity of demand in a local energy system is both much greater than the centralised system and is also specific to the local system. It is therefore essential that these systems have robust and high performance control systems to ensure supply and demand matching and high power quality can be achieved at all times. Ideally this same control system should be able to make best use of local energy system energy storage to enable it to be used as a flexible, highly responsive energy supply and/or demand for the centralised infrastructure. In this thesis, a comprehensive literature survey has identified that there is no scientific and rigorous method to assess the controllability or the design of control systems for these local energy systems. Thus, the main challenge of the work described in this thesis is that of a controller design method and modelling approach for CHP based local energy systems. Specifically, the main research challenge for the controller design and modelling methodology was to provide an accurate and stable system performance to deliver a reliable tracking of power drawn/supplied to the centralised infrastructure whilst tracking the require thermal comfort in the local energy systems buildings. In the thesis, the CHPV system has been used as a case study. A CHPV based solution provides all the benefits of CHP combined with the near zero carbon building/local network integrated PV power generation. CHPV needs to be designed to provide energy for the local buildings’ heating, dynamic ventilating system and air-conditioning (HVAC) facilities as well as all electrical power demands. The thesis also presents in addition to the controller design and modelling methodology a novel CHPV system design topology for robust, reliable and high-performance control of building temperatures and energy supply from the local energy system. The advanced control system solution aims to achieve desired building temperatures using thermostatic control whilst simultaneously tracking a specified national grid power demand profile. The theory is innovative as it provides a stability criterion as well as guarantees to track a specified dynamic grid connection demand profile. This research also presents: design a dynamic MATLAB simulation model for a 5-building zone commercial building to show the efficacy of the novel control strategy in terms of: delivering accurate thermal comfort and power supply; reducing the amount of CO2 emissions by the entire energy system; reducing running costs verses national rid/conventional approaches. The model was developed by inspecting the functional needs of 3 local energy system case studies which are also described in the thesis. The CHPV system is combined with supplementary gas boiler for additional heating to guarantee simultaneous tracking of all the zones thermal comfort requirements whilst simultaneously tracking a specified national grid power demand using a Photovoltaics array to supply the system with renewable energy to reduce amount of CO2 emission. The local energy system in this research can operate in any of three modes (Exporting, Importing, Island). The emphasise of the thesis modelling method has been verified to be applicable to a wide range of case studies described in the thesis chapter 3. This modelling framework is the platform for creating a generic controlled design methodology that can be applied to all these case studies and beyond, including Local Energy System (LES) in hotter climates that require a cooling network using absorption chillers. In the thesis in chapter 4 this controller design methodology using the modelling framework is applied to just one case study of Copperas Hill. Local energy systems face two types of challenges: technical and nontechnical (such as energy economics and legislation). This thesis concentrates solely on the main technical challenges of a local energy system that has been identified as a gap in knowledge in the literature survey. The gap identified is the need for a controller design methodology to allow high performance and safe integration of the local energy system with the national grid infrastructure and locally installed renewables. This integration requires the system to be able to operate at high performance and safely in all different modes of operation and manage effectively the multi-vector energy supply system (e.g. simultaneous supply of heat and power from a single system).

Tese de mestrado. Engenharia Electrotécnica e de Computadores. 2005. Faculdade de Engenharia. Universidade do Porto

Orientador: Fábio Roberto Chavarette / Resumo: A voz é a principal ferramenta de comunicação da espécie humana e a maioria das pessoas dependem dela direta ou indiretamente em sua profissão. Sua produção deve-se ao funcionamento harmônico de sistemas fisiológicos distintos, resumidamente é o resultado da iteração do fluxo de ar vindo dos pulmões, dos tecidos deformáveis das pregas vocais e da onda de pressão acústica. Este trabalho inicialmente mostrará o estudo do comportamento assimétrico das pregas vocais causado por uma diferença entre a rigidez das pregas direita e esquerda. Para isso será utilizado uma modelagem que caracterizou-se como sistema de Van der Pol fortemente acoplado. O objetivo principal deste trabalho é estudar a dinâmica do movimento de pregas vocais com rigidez assimétrica e sincronizar este movimento através do método de controle linear ótimo, mostrando o seu funcionamento com valores distintos da rigidez para cada caso. Assim, o projeto de controle se mostra eficiente produzindo um bom funcionamento das pregas vocais, possibilitando a produção do som mesmo em pregas vocais doentes (assimétricas). / Abstract: The Voice is the main means of communication of human beings, and most people depend directly or indirectly on it in their professions. Its emission is due to the harmonious operation of dierent physiological systems; in sum, it results from the interaction of air coming from the lungs, the deformable tissues of the vocal folds, and an acoustic pressure wave. Initially, this work shall present the asymmetric behavior of the vocal folds caused by a dierence between the stiness value of the right and left folds. To do so, a mathematical model characterized as a strongly coupled Van der Pol system was used. The main objective of this work is to study the dynamics of the movement of vocal folds with asymmetric stiness and synchronize this movement through the optimal linear control method, showing their operation with dierent values of stiness for each case. Therefore, the control design has proven to be ecient, generating a good operation for the vocal folds and rendering possible the emission of sound even in diseased (asymmetric) vocal folds. / Doutor

Master of Engineering (Research) / This thesis, by developing a Miniature Aerial Vehicle (MAV) hovering platform, presents a practical solution to allow researchers and students to implement their theoretical methods for guidance and navigation in the real world. The thesis is not concerned with the development of guidance and navigation algorithms, nor is it concerned with the development of external sensors. There have been some recent advances in guidance and navigation towards developing algorithms and simple sensors for MAVs. The task of developing a platform to test such advancements is the subject of this thesis. It is considered a difficult and time consuming process due to the complexities of autonomous flight control and the strict size, weight and computational requirements of this type of system. It would be highly beneficial to be able to buy a platform specifically designed for this task that already possesses autonomous hovering capability and the expansion connectivity for interfacing your own custom developed sensors and algorithms. Many biological and computer scientists would jump at the opportunity to maximize their research by real world implementation. The development of such a system is not a trivial task. It requires a great deal of understanding in a broad range of fields including; Aeronautical, Microelectronic, Mechanical, Computer and Embedded Software Engineering in order to create a successful prototype. The challenge of this thesis was to design a research platform to enable easy implementation of external sensors and guidance algorithms, in a real world environment for research and education. The system is designed so it could be used for a broad range of testing experiments. After extensive research in current MAV and avionics design it became obvious in several areas the best available products were not sufficient to meet the needs of the proposed platform. Therefore it was necessary to custom design and build; sensors, a data acquisition system and a servo controller. The latter two products are available for sale by Jimonics (www.jimonics.com). It was then necessary to develop a complete flight control system with integrated sensors, processor and wireless communications network which is called ‘The MicroBrain’. ‘The MicroBrain’ board measures only 45mm x 35mm x 11mm and weighs ~11 grams. The coaxial contra-rotating MAV platform design provides a high level of mechanical stability to help minimise the control system complexity. The platform was highly modified from a commercially available remotely controlled helicopter. The system incorporates a novel collision protection system that was designed to also double as a mounting place for external sensors around its perimeter. The platform equipped with ‘The MicroBrain’ is capable of fully autonomous hover. This provides a great base for testing guidance and navigational sensors and algorithms by decoupling the difficult task of platform design and low-level stability control. By developing a platform with these capabilities the researcher can now focus on the guidance and navigation task, as the difficulties in developing a custom platform have been taken care of. This therefore promotes a faster evolution of guidance and navigational control algorithms for MAVs.

Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains ix, 86 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 82-86).

<p>Syftet med denna uppsats var att beskriva och analysera projektcontrollerns roll inom de projektintensiva enheterna FACTS och Substations på ABB AB. Studien bygger på tre personliga intervjuer utförda med projektcontrollers samt sex platsannonser som analyserats. Teorin består av två delar, dels projektaspekten och dels controlleraspekten. Första delen behandlar vad ett projekt är och vad det innebär att jobb i projektform. Andra delen, controlleraspekten, handlar om controllers ursprung kontra dagens roll och dess arbetsuppgifter. I empirin presenteras intervjuerna samt en sammanställning över platsannonser på projektcontroller. Därefter presenteras analysen av resultat som framkom genom intervjuerna och platsannonserna. Författarna utgår från rubrikerna projektstyrning och projektcontrollers roll. Studiens analys sammankopplas med den valda teorin, med utgångspunkt i studiens problemställning. Ett projekt kan variera i storlek och komplexitet likaså antalet projekt som ABB AB driver. Tids och kostnadsaspekten är väldigt viktig, likaså kontakten med kunden. ”Erfarenhetsåtervinning” innebär att utvärdering sker på vad som gått bra och mindre bra. Allt för att lära sig och bli bättre till nästa projekt. Projektcontroller är något som en ekonom kan avancera sig upp genom företaget och dennes roll är vad individen själv gör den till. Företagen anger vissa kvalifikationer som jobben kräver, men slutligen är det individen själv, som med egen erfarenhet och intressen, som formar rollen.</p>

<p>This master thesis was carried out at the Department of Aerodynamics and Flight Mechanics at Saab Aerosystems, Linköping, Sweden. It makes up the author’s final work prior to graduation in the field Applied Physics and Electrical Engineering at the Department of Electrical Engineering at The Linköping Institute of Technology (LiTH), Linköping, Sweden.</p><p> </p><p>The objective of the paper was to study a non-uniform helicopter rotor downwash model in forward flight for the unmanned helicopter Skeldar, which is under development at Saab. The main task was to compare the mentioned model with today’s uniform downwash model in order to find differences and similarities. This was done both from a modeling and a controlling perspective. To start with, an introduction is given which is followed by a helicopter theory chapter. The following three chapters deal with the theory of induced velocity, the helicopter model and the Linear Quadratic Regulator (LQR). Finally, the results are presented and discussed.</p><p> </p><p>The downwash models were derived using Momentum Theory (MT) and Blade Element Theory (BET). These two theories were combined in order to find a connection between the induced velocity and the rotor thrust coefficient. The non-uniform downwash model that was studied is proposed by Pitt & Peters and describes a linear variation of the induced velocity in the longitudinal plane.</p><p> </p><p>For the control, a LQ-regulator was chosen since it is easily implemented in MATLAB and it stabilizes the plant model by feedback and consequently creates a robust system. Before the controller could be implemented, the models had to be reduced and the states had to be divided into longitudinal and lateral ones.</p><p> </p><p>The comparison between the open systems clearly shows that differences in the inflow models propagate to all states and consequently the helicopter behaves differently in all planes. Great discrepancies are apparent for the angular velocities <em>p</em> and <em>q</em>. For Pitt & Peters’ model those states are believed to be strongly affected by the system’s positive real pole, causing a rather unstable behavior. When the systems were closed by feedback, the differences were reduced dramatically. Pitt & Peters’ model resulted in greater overshoots than the uniform model, but the overall behavior of all states was rather similar for the two models.</p><p> </p><p>It is concluded, that the adaption of Pitt & Peters’ inflow model does not make any substantial difference when a controller is implemented. The differences between the open systems, however, are reason enough to question Pitt & Peters’ model. In order to evaluate the non-uniform model properly, it has to be compared to suitable flight data which is still lacking up to this date.</p>

<p>Since a few years, flat screen TVs, such as LCD and plasma, has come to completelydominate the market of televisions. In a SoC solution for digital TVs, severalprocessors are used to obtain a decent image quality. Some of the processorsneed temporal information, which means that whole frames need to be storedin memory, which in turn motivates the use of SDRAM memory. When higherdemands of resolution and image quality arrives, greater pressure is put on theperformance of the SoC memory subsystem, to not become a bottleneck of thesystem.</p><p>In this master thesis project, a model of an existing SoC for digital TVs is usedto benchmark and evaluate the performance of an SDRAM memory controllerarchitecture study. The two major features are the ability to reorder transactionsand the compatibility with DDR3. By introducing reordering of transactions, thechoice is given to the memory controller to service memory requests in an orderthat decreases bank conflicts and read/write turn arounds. Measurements showthat a utilization of 86.5 % of the total available bandwidth can be achieved, whichis 18.5 percentage points more, compared to an existing nonreordering memorycontroller developed by NXP.</p>