Siga este link para ver outros tipos de publicações sobre o tema: Optimized Control.
Teses / dissertações sobre o tema "Optimized Control"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Veja os 50 melhores trabalhos (teses / dissertações) para estudos sobre o assunto "Optimized Control".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Veja as teses / dissertações das mais diversas áreas científicas e compile uma bibliografia correta.
1
He, Jincan, e Sundhanva Bhatt. "Mission Optimized Speed Control". Thesis, KTH, Fordonsdynamik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-223334.
Texto completo da fonteResumo:
Transportation underlines the vehicle industry's critical role in a country's economic future.The amount of goods moved, specically by trucks, is only expected to increase inthe near future. This work attempts to tackle the problem of optimizing fuel consumptionin Volvo trucks, when there are hard constraints on the delivery time and speed limits.Knowledge of the truck such as position, state, conguration etc., along with the completeroute information of the transport mission is used for fuel optimization.Advancements in computation, storage, and communication on cloud based systems, hasmade it possible to easily incorporate such systems in assisting modern eet. In this work,an algorithm is developed in a cloud based system to compute a speed plan for the completemission for achieving fuel minimization. This computation is decoupled from thelocal control operations on the truck such as prediction control, safety, cruise control, etc.;and serves as a guide to the truck driver to reach the destination on time by consumingminimum fuel.To achieve fuel minimization under hard constraints on delivery (or arrival) time andspeed limits, a non-linear optimization problem is formulated for the high delity modelestimated from real-time drive cycles. This optimization problem is solved using a Nonlinearprogramming solver in Matlab.The optimal policy was tested on two drive cycles provided by Volvo. The policy wascompared with two dierent scenarios, where the mission demands hard constraints ontravel time and the speed limits in addition to no trac uncertainties (deterministic). with a cruise controller running at a constant set speed throughout the mission. Itis observed that there is no signicant fuel savings. with maximum possible fuel consumption; achieved without the help of optimalspeed plan (worst case). It is seen that there is a notable improvement in fuelsaving.In a real world scenario, a transport mission is interrupted by uncertainties such as trac ow, road blocks, re-routing, etc. To this end, a stochastic optimization algorithm is proposedto deal with the uncertainties modeled using historical trac ow data. Possiblesolution methodologies are suggested to tackle this stochastic optimization problem.
2
Wang, Ning. "Model-Free Optimized Tracking Control Heuristic". Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40911.
Texto completo da fonteResumo:
Tracking control algorithms often target the convergence of a tracking error. However, this can be at the expense of other important system characteristics, such as the control effort used to annihilate the tracking error, transient response, or steady-state characteristics, for example. Furthermore, most tracking control methods assume prior knowledge of the system dynamics, which is not always a realistic assumption, especially in the case of highly complex systems.
In this thesis, a model-free optimized tracking control architectural heuristic is proposed. The suggested feedback system is composed of two control loops. The first is the tracking loop. It focuses on the convergence of the tracking error. It is implemented using two different model-free control algorithms for comparison purpose: Reinforcement Learning (RL) and the Nonlinear Threshold Accepting (NLTA) technique. The RL scheme reformulates the tracking error combinations into a form of Markov-Decision-Process (MDP) and applies Q-Learning to build the best tracking control policy for the dynamic system under consideration. On the other hand, the NLTA algorithm is applied to tune the gains of a PID controller. The second control loop is in the form of a nonlinear state feedback loop. It is implemented using a feedforward artificial neural network (ANN) to optimize a system-wide cost function which can be flexible enough to encompass a set of desired design requirements pertaining to the targeted system behavior. This may include, for instance, the target overshoot, settling time, rise time, etc. The proposed architectural heuristic provides a model-free framework to tackle such control problems, in the sense that the plant's dynamic model is not required to be known in advance. Yet, at least a subset of the stability region of the optimized gains has to be known in advance so that it can provide a search space for the optimization algorithms. Simulation results on two dynamic systems demonstrate the superiority of the proposed control scheme.
3
Ruedisueli, Robert Louis. "Cyclically optimized electrochemical processes /". Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/10576.
Texto completo da fonte
4
Shook, David Adam. "Control of a benchmark structure using GA-optimized fuzzy logic control". [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1088.
Texto completo da fonte
5
Uurtonen, Tommi. "Optimized Power Control for CDMA System using Channel Prediction". Thesis, Linköping University, Department of Science and Technology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-3697.
Texto completo da fonteResumo:
In an optimal power control scheme for a Code Division Multiple Access (CDMA) system all mobile stations signals should arrive to the base station at equal power. If not, stronger singals may cause too much interference and block out weaker ones. Commonly used power control schemes utilizes the Signal to Interference Ratio (SIR) to design a Power Control Command (PCC) to adjust the transmit power of the mobile station. A significant problem within the conventional methods is the slow SIR recovery due to deep channel fades. Conventional methods base the PCC on the previous channel state when in fact, the channel state may have significantly changed when transmission occurs. These channel changes may cause the SIR to drop or rise drastically and lead to uncontrollable Multi Access Interference (MAI) resulting in power escalation and making the system unstable. In order to overcome power escalation and improve the recovery from deep fades a novel power control method has been developed. Based on Linear Quadratic Control and Kalman filtering for channel prediction this method designs the PCC based on the coming channel state instead of the current. This optimizes the PCC for the channel state where transmission occurs. Simulations show that this control scheme outperforms previous methods by making the impacts of the deep fades less severe on the SIR and also improves the overall SIR behaviour.
6
Naveed, Muhammad. "Multicore Optimized Real-Time Protocol for Power Control Networks". Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-90367.
Texto completo da fonteResumo:
The Technology today is changing at a fast pace. The growth of computers and telecommunications over the past three decades has been extraordinary. We today are at the point where all technologies related to communication and data transfer are submerging to a common platform. A number of different methods are available for data communication or data transfer. The important factor in all communication setups is to satisfy user demands with low cost and reliability. The area of interest for this thesis is future energy substations and wind mills. In order to make things more straight forward and see its different options and capabilities the focus is on designing and implementing a new energy protocol called Energy Real Time Protocol (eRTP) based on Iyad Real Time Protocol (iRTP) [2]. The protocol is designed to meet the requirements of power and energy networks in terms of sending the energy parameters with VoIP data (optional) among power stations at different locations. Keeping in mind the importance transferring energy parameters in real-time, the presented protocol has built upon small individual algorithms/modules designed for multi-core architecture. Each module is supposed to be processed by an individual core/processor in parallel.
7
Watanabe, Yoko. "Stochastically optimized monocular vision-based navigation and guidance". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/22545.
Texto completo da fonteResumo:
Thesis (Ph. D.)--Aerospace Engineering, Georgia Institute of Technology, 2008.Committee Chair: Johnson, Eric; Committee Co-Chair: Calise, Anthony; Committee Member: Prasad, J.V.R.; Committee Member: Tannenbaum, Allen; Committee Member: Tsiotras, Panagiotis.
8
Holladay, Seth R. "Optimized Simulation of Granular Materials". BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3856.
Texto completo da fonteResumo:
Visual effects for film and animation often require simulated granular materials, such as sand, wheat, or dirt, to meet a director's needs. Simulating granular materials can be time consuming, in both computation and labor, as these particulate materials have complex behavior and an enormous amount of small-scale detail. Furthermore, a single cubic meter of granular material, where each grain is a cubic millimeter, would contain a billion granules, and simulating all such interacting granules would take an impractical amount of time for productions. This calls for a simplified model for granular materials that retains high surface detail and granular behavior yet requires significantly less computational time. Our proposed method simulates a minimal number of individual granules while retaining particulate detail on the surface by supporting surface particles with simplified interior granular models. We introduce a multi-state model where, depending on the material state of the interior granules, we replace interior granules with a simplified simulation model for the state they are in and automate the transitions between those states. The majority of simulation time can thus be focused on visible portions of the material, reducing the time spent on non-visible portions, while maintaining the appearance and behavior of the mass as a whole.
9
Vieira, Turnell Alice. "Decentralized Secondary Frequency Control in an Optimized Diesel PV Hybrid System". Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-240405.
Texto completo da fonteResumo:
This research argues that a diesel-based isolated electrical system can be optimized byintegrating a high share of solar photovoltaic (PV) generation and that the frequencystability of such system can be improved by including the PV participation in frequencyregulation. A case study is developed in order to explore an island’s expansion of theinstalled generating capacity and its optimization. This study uses the tool HOMER tosolve the optimization problem and PowerFactory to verify the frequency stability of theproposed system. The PV integration allows for a reduction of diesel fuel consumption,emissions and generation costs. Additionally, in high PV penetration scenarios, the reducedinertia in such systems can lead to high frequency deviations that may trip the systemprotection. The study demonstrates that the instantaneous frequency deviation after a loadand generation imbalance can be reduced by designing the PVs to operate with an allocatedreserve and a decentralized time-based secondary frequency control. The frequency stabilitywas achieved after different disturbance scenarios under high PV penetration and reducedavailable inertia, indicating that high PV integration is economically and technically feasiblein small island grids.I detta examensarbete studeras hur ett dieselbaserat och isolerat elsystem kan optimeras genom att integrera en hög andel solceller (PV) i elproduktionen och att frekvensstabilitet kan förbättras när PV användas i regleringen. En fallstudie har utvecklats under denna forskning för att analysera en ökning av den installerade generationskapacitet vid en ö samt hur detta kan optimeras. I denna studie användas verktyget HOMER för modeloptimering och PowerFactory för att testa den optimerade systemfrekvens stabilitet. Med PV generation kan diesel konsumption, utsläpp och kostnader minskas för hela systemet. En hög andel PV i generationen reducerar elsystemet totala svängmassa vilket kan ledda till avvikelser i systemfrekvensen som kan ursaka att skyddsystem aktiveras. Studien demonstrerar att den momentana systemavvikelsen efter en obalans kan reduceras genom att designa PV i systemet med en allokerad reserv och en decentraliserad och tidsbaserad sekundär frekvensreglering. Frekvensstabiliteten nåddes i olika obalans scenarier med hög andel solcellgeneration och misnkat svängsmassa. Detta tyder på att en hög andel PV integration är både ekonomisk- och tekniskt möjligt i mindre elsystem.
10
Siegel, Jakob. "A CUDA optimized Lattice Boltzmann method implementation using control-structure splitting techniques". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 69 p, 2009. http://proquest.umi.com/pqdweb?did=1885754631&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Texto completo da fonte
11
Rapp, Tobias. "A COP optimized control system for a CO₂ based automotive A/C-system". Thesis, Nelson Mandela Metropolitan University, 2007. http://hdl.handle.net/10948/773.
Texto completo da fonteResumo:
In the last few years carbon dioxide received increasing attention as a possible replacement for fluorocarbon-based refrigerants used within present automotive A/C system technology. R-134a is harmless to the ozone layer but the greenhouse effect is more than 1300 times higher than that of an equivalent amount of CO2. Alternative refrigerants are natural gasses such as propane and butane, however these gasses are considered explosive. With many objections raised it appears if CO2 will be the future refrigrant for automotive use. One concern with R-744 is its high operating pressure and suction/discharge pressure difference when compared to common refrigeration processes. A major problem with the CO2 cycle is the loss of effciency at high ambient temperatures. With a COP optimized control system for the expansion value based on pressure, temperature and mass flow of the refrigerant, an effective A/C system for CO2 could be deleloped. This resrach offers basic knowledge of refrigerant cycles and gives an overall view of the refrigerant change-over problem. With the results obtained from the experimental work a better understanding of the CO2 cycle and a better understanding towards effective A/C systems have been realized.
12
BETTONI, DAVIDE. "Design and assessment of optimized control strategies for solar heating and cooling system". Doctoral thesis, Università degli studi di Bergamo, 2014. http://hdl.handle.net/10446/30395.
Texto completo da fonteResumo:
Solar Combi+ systems are thermal systems used for satisfy the thermal loads for DHW, heating and cooling using solar thermal energy. They are normally complex systems made of an elevate number of components. These components are required to operate correctly and harmoniously in order to achieve high system performance. The traditional design process of these applications is based on numerical simulations, which are used for understanding the performance of the system with respect to different parameters (geometrical dimensions, thermal capacity, orientation) or boundary conditions (thermal loads or climatic data considered). At the same time, the optimization of the control strategy is developed using the same models that, in order to represent the reality, need to be validated with monitoring data or laboratory tests. The process of numerical model validation, sensitivity analysis and optimization of the control is a time consuming process.
In order to explore the possibility of reducing the simulation effort, an alternative approach has been developed in this thesis based on another approach. In the beginning, a rough numerical model is created and used for the design of the controller without undergoing the model validation steps. The fine-tuning of the controller, instead, is done directly on field where the control parameters are optimized using an appropriate learning methodology. Following this new approach, time saving are realized because the optimization of the control is fast and the validation of the model components is skipped. This makes the control optimization process more high-level without requiring access to monitoring data, laboratory test or deep knowledge of the system. Moreover, the selection of the software adopted for the development of the controller (LabVIEW) allow to share the same code for real-time control implementation as well as the numerical simulation. A direct connection with the software that simulate the energy fluxes between different components (Trnsys) and the software of the controller (LabVIEW) has been developed. Two innovative control methodologies are discussed in the thesis. The first one is related to the design of the controller using the fuzzy logic (Fuzzy controller) the other one is relative to the ability of the controllers to optimize themselves from the actual data taken from the field (Q-learning). These two methods can be efficiently connected each other allowing for a robust model-free learning approach able to find the best operative point of the fuzzy controller.
Following this path, the thesis here presented is composed by a the first chapter where an introduction of the solar thermal systems from the simple configuration (only for DHW demand) to the more complex systems (solar Combi+) is given. In the end of the chapter a review on the logic used in the control of such a systems is reported. In the second chapter the numerical models adopted are presented, with a focus on the boundary conditions considered and the effects on the system loads. The third chapter is devoted to present the methodology of validation developed and its application to the models used in the simulation. In the fourth chapter a Solar Combi+ system for residential application is presented with a focus on the control structure, the sensitivity analysis and the traditional control optimization process. Finally in the fifth chapter the advanced control logic methodologies are presented with an introduction on Fuzzy Logic and on Reinforcement Learning. The chapter continues with a focus on the Fuzzy logic controller and the Q-learning controller algorithm description. In the final part of the thesis this methodology is applied to a simple well known solar system to show the characteristics, the operation and the potential application on the other components of the Solar Combi+ system.
13
BETTONI, DAVIDE. "Design and assessment of optimized control strategies for solar heating and cooling system". Doctoral thesis, Università degli studi di Bergamo, 2014. http://hdl.handle.net/10446/222112.
Texto completo da fonteResumo:
Solar Combi+ systems are thermal systems used for satisfy the thermal loads for DHW, heating and cooling using solar thermal energy. They are normally complex systems made of an elevate number of components. These components are required to operate correctly and harmoniously in order to achieve high system performance. The traditional design process of these applications is based on numerical simulations, which are used for understanding the performance of the system with respect to different parameters (geometrical dimensions, thermal capacity, orientation) or boundary conditions (thermal loads or climatic data considered). At the same time, the optimization of the control strategy is developed using the same models that, in order to represent the reality, need to be validated with monitoring data or laboratory tests. The process of numerical model validation, sensitivity analysis and optimization of the control is a time consuming process. In order to explore the possibility of reducing the simulation effort, an alternative approach has been developed in this thesis based on another approach. In the beginning, a rough numerical model is created and used for the design of the controller without undergoing the model validation steps. The fine-tuning of the controller, instead, is done directly on field where the control parameters are optimized using an appropriate learning methodology. Following this new approach, time saving are realized because the optimization of the control is fast and the validation of the model components is skipped. This makes the control optimization process more high-level without requiring access to monitoring data, laboratory test or deep knowledge of the system. Moreover, the selection of the software adopted for the development of the controller (LabVIEW) allow to share the same code for real-time control implementation as well as the numerical simulation. A direct connection with the software that simulate the energy fluxes between different components (Trnsys) and the software of the controller (LabVIEW) has been developed. Two innovative control methodologies are discussed in the thesis. The first one is related to the design of the controller using the fuzzy logic (Fuzzy controller) the other one is relative to the ability of the controllers to optimize themselves from the actual data taken from the field (Q-learning). These two methods can be efficiently connected each other allowing for a robust model-free learning approach able to find the best operative point of the fuzzy controller. Following this path, the thesis here presented is composed by a the first chapter where an introduction of the solar thermal systems from the simple configuration (only for DHW demand) to the more complex systems (solar Combi+) is given. In the end of the chapter a review on the logic used in the control of such a systems is reported. In the second chapter the numerical models adopted are presented, with a focus on the boundary conditions considered and the effects on the system loads. The third chapter is devoted to present the methodology of validation developed and its application to the models used in the simulation. In the fourth chapter a Solar Combi+ system for residential application is presented with a focus on the control structure, the sensitivity analysis and the traditional control optimization process. Finally in the fifth chapter the advanced control logic methodologies are presented with an introduction on Fuzzy Logic and on Reinforcement Learning. The chapter continues with a focus on the Fuzzy logic controller and the Q-learning controller algorithm description. In the final part of the thesis this methodology is applied to a simple well known solar system to show the characteristics, the operation and the potential application on the other components of the Solar Combi+ system.
14
Svensson, Eskil. "Evaluation of Smart Split-Range Control Strategies for Optimized Turbine and Steam Control in Pulp and Paper Plants". Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76027.
Texto completo da fonte
15
Cao, Kun. "The development of a pulse-optimized flow control method for turbocharger turbine performance improvement". Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/44972.
Texto completo da fonteResumo:
A new turbocharger turbine concept that enhances exhaust energy recovery has been developed; it is known as the ‘rotating vane turbine’ (RVT). It aims to address the negative impact of the pulsating exhaust flow on the turbocharger turbine, so that the exhaust energy can be recovered more efficiently compared to the state of art turbocharging technologies. Different from traditional turbine configurations, in which the nozzle is stationary, the RVT incorporates a rotating nozzle ring at a relatively low speed. It thus minimises the deviation of the turbine incidence angle from the optimal design angle on average through a pulse cycle, it as such leads to an improvement of turbine performance. Two control methods are investigated for the rotating nozzle: a passive self-rotation and one that is controlled from the outside with the use of an external driving turbine. The geometry of the rotating nozzle ring is also optimized to reduce the incidence loss on the nozzle blade under unsteady flow. The new RVT is studied through numerical calculation in order to demonstrate that the rotating nozzle ring can adaptively change the flow angle at the turbine inlet through a pulse cycle. As a result, the turbine operating point is pushed to better performance region with higher turbine efficiency and lower pressure ratio, compared to a traditional stationary nozzle ring. The flow analysis shows that the turbine performance improvement is due to the reduction of the flow separation on the turbine blade under sub-optimal operating conditions. Detailed experimental testing is also carried out to further validate the new concept. Two rotating nozzles with different angles are tested under different flow frequencies, turbine speeds, turbine loads and mass flow rates. As comparisons, stationary vane turbine (SVT) and nozzleless turbine are also tested under the same operating conditions as for RVT. The testing results demonstrate that, the rotating nozzle ring can reduce the amplitude of the flow pulses, thereby reducing the unsteadiness level of the turbine operation. Similar to the simulation results, a significant increase in average turbine efficiency as well as a reduction of turbine pressure ratio are observed for RVT, compared to for SVT or nozzleless turbine. A preliminary study of 1D engine simulation is also carried out to investigate the impact of the new RVT on the engine performance. The simulation results show that, the back pressure of the engine with RVT is reduced based on the same engine power output. This indicates the new RVT can effectively reduce the BSFC of an engine, compared to a traditional SVT.
16
Lenner, Andreas, e Sebastian Zawadzki. "Placement of work stations for optimized and efficient cooperation in the Östgöta control center". Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-137667.
Texto completo da fonteResumo:
Det finns olika sätt att öka kapaciteten hos en flygledare. En av de är att göra samordningar mer effektiva. Samordningar sker idag via datalänk eller verbalt, då genom telefonsamordning eller face-to-face. Det finns även icke verbala samordningar där bara kroppsspråk står för en del av kommunikationen. På en kontrollcentral utförs många samordningar och informationsdelningar mellan flygledare. Detta görs för att kunna hålla en hög säkerhet men ändå arbeta på ett effektivt sätt. Östgöta kontrollcentral, ÖKC, har undersökts för att se om informationsdelningen kan bli effektivare samt om en flygledarassistent kan stötta två flygledare samtidigt. Med hjälp av en teoretisk referensram och litteraturstudie har det visat sig att bland annat Lean production kan appliceras på området för att utvärdera ÖKC. Författarna har observerat den operativa verksamheten på ÖKC och samlat data som i sin tur ligger till grund för de mätningar som gjorts. Därefter har ett alternativt ÖKC tagits fram med förankring i teorin om hur kontrollcentraler bör se ut för en bra social samverkan och teamwork. Utifrån data från observationen är informationssträckan som information inne på ÖKC måste färdas 150,8 meter. Detta mätetal är undersökningens viktigaste mätetal och visar att alternativet har motsvarande 130,5 meter informationssträcka, vilket ger en minskning med 20,3 meter.
17
Bejjenki, Praneeth Kumar, Muneeb Ahmed Goraya e Syed Fovad Moid. "OPTIMIZED FUZZY BASED POWER CONTROL STRATEGY IN COGNITIVE RADIO NETWORKS IN MULTI FADING PROPAGATION ENVIRONMENTS". Thesis, Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-4160.
Texto completo da fonteResumo:
In this thesis we have considered a cognitive radio network (CRN) with a pair of primary user (PU) and secondary user (SU) in spectrum sharing networks in path-loss and without path-loss propagation environments under identically distributed m-Nakagami fading channel. The thesis consists of three parts. In the first part we propose an optimized Takagi-Sugeno Fuzzy Inference System (FIS) based power control strategy in cognitive radio networks (CRN) in spectrum sharing network in without path-loss propagation environment. The second part proposes an optimized Takagi-Sugeno FIS based power control strategy in cognitive radio networks in spectrum sharing network in path-loss propagation environment. For without path-loss propagation environment the proposed FIS takes the interference channel gain ratio between SU transmitter (CUtx) and PU receiver (PUrx) and Signal to Noise Ratio (SNR) towards PU transmitter (PUtx) as antecedents and outputs the power scaling factor for SU. For path-loss propagation environment the proposed FIS takes the relative distance ratio between CUtx and PUrx and SNR towards PUtx as antecedents and outputs the power scaling factor for SU. The output power scaling factor is used to vary the transmit power of SU such that it does not degrade the quality of service (QoS) of PU link. The third part presents an implementation of orthogonal frequency division multiplexing (OFDM) transmission technique in CRN. The OFDM technique has intellectual attractive features like coping with the inter symbol interference (ISI), while providing increasing spectral efficiency and improved performance. This can be used in emergency conditions where transmission requires reliability and high data rate. The OFDM transmission technique is applied towards SU transmitter in CRN, which enables SU to utilize the spectrum efficiently under various fading environments. Spectrum sharing networks in with and without path-loss propagation environments and OFDM transmission were tested for bit error rate (BER) performance after fading effects from m-Nakagami fading channel. We conclude that by applying Takagi-Sugeno Fuzzy Inference System (FIS) based power control strategy we can improve the BER performance of PU when compared with no power control strategy and with other fuzzy based power control technique. OFDM transmission technique gives us better data rate and slightly improved BER in CRN hence making it suitable for use in emergency conditions.mobile: 0735032048 (Muneeb Goraya)
18
Stalter, Olivier. "Inverter-integrated, sensorless and power-optimized position control of a concentrating photovoltaic dual-axis tracker". Grenoble INPG, 2009. http://www.theses.fr/2009INPG0186.
Texto completo da fonteResumo:
L’intérêt du photovoltaïque à concentration (CPV) réside autant dans le faible volume de semi-conducteur que dans le fort rendement des cellules solaires III-V. Toutefois, du fait du dispositif optique, un positionnement mécanique très précis du générateur CPV via un traqueur solaire à deux axes de rotation est nécessaire. La première partie du travail de thèse consista à développer un onduleur hybride ou « Tracking Inverter » capable d’injecter le courant produit par un traqueur CPV tout en réalisant son positionnement. La seconde partie consista à implémenter les procédés de tracking classiques (capteur solaire, calcul astronomique ou hybride) afin d’évaluer leurs performances et leurs limites. Enfin, la réalisation majeure de la thèse fût le développement d’un nouveau procédé de tracking sans capteur et basé sur la puissance électrique de l’onduleur. La précision, la sensibilité et la fiabilité du Mechanical Maximum Power Point Tracker (MPPTm) en modes dégradés vinrent clore l’étude.
19
Guo, Hui. "Design of innovative systems for the optimized control of reactivity in Gen-IV fast neutron reactors". Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0245.
Texto completo da fonteResumo:
Les réacteurs de quatrième génération pourraient tirer parti du spectre des neutrons rapides pour optimiser l'utilisation des ressources en uranium, faciliter la gestion des matières fissiles et améliorer la transmutation des déchets nucléaires. La barre de commande est habituellement combinée un réseau des aguilles non étanchées en carbure de bore (B4C) comme élément absorbant. Différents critères technologiques limitent la durée d’utilisation du B4C en irradiation. Par conséquent, des éléments absorbants alternatifs tels que l'oxyde de gadolinium (Gd2O3), l'oxyde d'europium (Eu2O3) et le diborure d'hafnium (HfB2) sont utilisés dans des configurations mixtes spécifiques contenant du modérateur pour optimiser la conception des barres de commande dans les réacteurs rapides refroidi au sodium (RNR-Na).Dans les réacteurs rapides « classiques », la barre de commande est très souvent le seul système de contrôle. Il est donc très difficile de démontrer la non-fusion du combustible lors d'accidents de remontée intempestive des barres (RIB). Par conséquent, deux conceptions de poisons consommables (PC) sont proposées et étudiées pour réduire les effets de RIB. La première conception de PC charge des actinides mineurs en mode homogène ou hybride. La deuxième conception combine B4C et modérateurs dans les assemblages dédiés.Ces conceptions sont étudiées à l'aide de schémas de calcul avancé dans APOLLO3® qui sont développés et validés dans cette thèse. Ces conceptions sont utilisées dans un grand RNR-Na industriel et dans un petit RNR-Na modulaire, et montrent leur grande flexibilité pour optimiser le contrôle de la réactivité dans les réacteurs rapidesThe Generation-IV reactors could benefit from the fast neutron spectrum to maximize the utilization of uranium resources, improve the management of fissile materials, and help the transmutation of nuclear waste. As the absorption cross-sections decrease with incident neutron energy, the fast spectrum challenges its reactivity control.The conventional control rod is a cluster of open pins with boron carbide (B4C) as the absorber. ^10B enrichment can be adjusted to satisfy the requirements of different cores. However, the operating lifetime of B4C is limited due to its characteristics under irradiation. Alternative absorbers such as gadolinium oxide (Gd2O3), europium oxide (Eu2O3) and hafnium diboride (HfB2) may present some advantages and be used with local addition of moderators to optimize the design of control rods in sodium fast reactors (SFRs).In the conventional fast reactors, the control rod is usually the only reactivity control system, which would lead to fuel melting in control rod withdrawal (CRW) accidents. Therefore, two burnable poison (BP) designs are investigated to reduce core excess reactivity and thus improve the inherent safety performance of reactors. The first BP design load minor actinides in homogenous or hybrid mode. The second BP design combines depleted B4C and moderators in dedicated assemblies.These designs are investigated using the advanced calculation scheme in APOLLO3® that is developed and validated in this thesis. These designs are applied in a large industrial SFR and a small modular SFR, which proves their excellent flexibility to optimize reactivity control in a wide range of fast reactors
20
Chen, Zhongkai. "Optimized Walking of an 8-link 3D Bipedal Robot". Thesis, Paris, ENSAM, 2015. http://www.theses.fr/2015ENAM0027/document.
Texto completo da fonteResumo:
D'un point de vue énergétique, les robots marcheurs sont moins performants que les humains. Face à ce défi, cette thèse propose une approche pour contrôler et optimiser les allures de marche des robots bipèdes à la fois en 2D et 3D en considérant les fréquences propres du robot et par ajout de ressorts. L'étude porte essentiellement sur un robot bipède 2D à 5 corps et des pieds ponctuels ainsi qu'un robot bipède 3D à 8 corps avec des pieds sans masse à contact linéique. La commande en boucle fermée considérée est basée sur la méthode des contraintes virtuelles et la linéarisation par retour d'état. Suite à des études précédentes, la stabilité du robot bipède 2D est vérifiée par une section de Poincaré unidimensionnelle et étendue au robot bipède 3D à contact linéique avec le sol. L'optimisation est effectuée en utilisant la programmation quadratique séquentielle. Les paramètres optimisés incluent des coefficients de polynômes de Bézier et des paramètres posturaux. Des contraintes d'optimisation sont imposées pour assurer la validité de l'allure de marche. Pour le robot bipède 2D, deux configurations différentes de ressorts placés aux hanches sont étudiées. Ces deux configurations ont permis de réduire le coût énergétique. Pour le robot bipède 3D, les paramètres d'optimisation sont séparés en deux parties : ceux décrivant le mouvement dans le plan sagittal et ceux du plan frontal. Les résultats de l'optimisation montrent que ces deux types de paramètres doivent être optimisés. Ensuite, des ressorts sont ajoutés respectivement par rapport au plan sagittal, par rapport au plan frontal puis dans les deux plans. Les résultats montrent que l'ajout des ressorts dans le plan sagittal permet de réduire significativement le coût énergétique et que l'association de ressorts dans le plan frontal améliore encore plus la consommation d'énergieFrom an energy standpoint, walking robots are less efficient than humans. In facing this challenge, this study aims to provide an approach for controlling and optimizing the gaits of both 2D and 3D bipedal robots with consideration for exploiting natural dynamics and elastic couplings. A 5-link 2D biped with point feet and an 8-link 3D biped with massless line feet are studied. The control method is based on virtual constraints and feedback linearization. Following previous studies, the stability of the 2D biped is verified by computing scalar Poincaré map in closed form, and now this method also applies to the 3D biped because of its line-foot configuration. The optimization is performed using sequential quadratic programming. The optimization parameters include postural parameters and Bézier coefficients, and the optimization constraints are used to ensure gait validity. For the 2D biped, two different configurations of hip joint springs are investigated and both configurations successfully reduce the energy cost. For the 3D biped, the optimization parameters are further divided into sagittal parameters and coronal parameters, and the optimization results indicate that both these parameters should be optimized. After that, hip joint springs are added respectively to the sagittal plane, the coronal plane and both these planes. The results demonstrate that the elastic couplings in the sagittal plane should be considered first and that the additional couplings in the coronal plane reduce the energy cost even further
21
Clem, Garrett Stuart. "An Optimized Circulating Vector Field Obstacle Avoidance Guidance for UnmannedAerial Vehicles". Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1530874969780028.
Texto completo da fonte
22
Buttgereit, David, Sebastian Bitzen, Jörg Benndorf e M. W. N. Buxton. "Real-Time Mining Control Cockpit: a framework for interactive 3D visualization and optimized decision making support". Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2018. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-231282.
Texto completo da fonteResumo:
Real-Time Mining is a research and development project within the European Union\'s Horizon 2020 initiative and consists of a consortium of thirteen European partners from five countries. The overall aim of Real-Time-Mining is to develop a real-time framework to decrease environmental impact and increase resource efficiency in the European raw material extraction industry. The key concept of the research conducted is to promote a paradigm shift from discontinuous to a continuous process monitoring and quality management system in highly selective mining operations.
The Real-Time Mining Control Cockpit is a framework for the visualization of online data acquired during the extraction at the mining face as well as during material handling and processing. The modules include the visualization of the deposit-model, 3D extraction planning, integrated data of the positioning-system as well as the visualization of sensor and machine performance data. Different tools will be developed for supporting operation control and optimized decision making based on real-time data from the centralized database. This will also integrate results from the updated resource model and optimized mine plan. The developed Real-Time Mining cockpit software will finally be integrated into a wider central control and monitoring station of the whole mine.
23
Kojima, Tetsuya Verfasser], Doncker Rik W. [Akademischer Betreuer] [De e Kay [Akademischer Betreuer] Hameyer. "Efficiency optimized control of switched reluctance machines / Tetsuya Kojima ; Rik Wivina Anna de Doncker, Kay Hameyer". Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1186069228/34.
Texto completo da fonte
24
Buttgereit, David, Sebastian Bitzen, Jörg Benndorf e M. W. N. Buxton. "Real-Time Mining Control Cockpit: a framework for interactive 3D visualization and optimized decision making support". TU Bergakademie Freiberg, 2017. https://tubaf.qucosa.de/id/qucosa%3A23188.
Texto completo da fonteResumo:
Real-Time Mining is a research and development project within the European Union\'s Horizon 2020 initiative and consists of a consortium of thirteen European partners from five countries. The overall aim of Real-Time-Mining is to develop a real-time framework to decrease environmental impact and increase resource efficiency in the European raw material extraction industry. The key concept of the research conducted is to promote a paradigm shift from discontinuous to a continuous process monitoring and quality management system in highly selective mining operations.
The Real-Time Mining Control Cockpit is a framework for the visualization of online data acquired during the extraction at the mining face as well as during material handling and processing. The modules include the visualization of the deposit-model, 3D extraction planning, integrated data of the positioning-system as well as the visualization of sensor and machine performance data. Different tools will be developed for supporting operation control and optimized decision making based on real-time data from the centralized database. This will also integrate results from the updated resource model and optimized mine plan. The developed Real-Time Mining cockpit software will finally be integrated into a wider central control and monitoring station of the whole mine.
25
Kojima, Tetsuya [Verfasser], Doncker Rik W. [Akademischer Betreuer] De e Kay [Akademischer Betreuer] Hameyer. "Efficiency optimized control of switched reluctance machines / Tetsuya Kojima ; Rik Wivina Anna de Doncker, Kay Hameyer". Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1186069228/34.
Texto completo da fonte
26
Schwarb, Hillary. "Optimized cognitive training: investigating the limits of brain training on generalized cognitive function". Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/47599.
Texto completo da fonteResumo:
Since antiquity, philosophers, theologians, and scientists have been interested in human memory; however, researchers today are still working to understand the capabilities, boundaries, and architecture. While the storage capabilities of long-term memory are seemingly unlimited (Bahrick, 1984), working memory, or the ability to maintain and manipulate information held in memory, seems to have stringent capacity limits (e.g., Cowan, 2001). Individual differences, however, do exist and these differences can often predict performance on a wide variety of tasks (cf. Engle, 2001). Recently, researchers have promoted the enticing possibility that simple behavioral training can expand the limits of working memory which indeed may also lead to improvements on other cognitive processes as well (cf. Morrison&Chein, 2011). The current study investigated this possibility. Recommendations from the skill training literature (cf. Schneider, 1985) were incorporated to create optimized verbal and spatial working memory training tasks. Significant performance improvements were evident across eight days of cognitive training using verbal and spatial adaptive n-back procedures. Training-related improvements were also evident for some untrained measures of visual short-term memory, attentional control, and working memory. These training effects, however, were not universal. Other measures of visual short-term memory and attentional control, as well as measures of fluid intelligence were unaffected by training.
27
Yan, Yu Pei. "A path planning algorithm for the mobile robot in the indoor and dynamic environment based on the optimized RRT algorithm". Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3951594.
Texto completo da fonte
28
Muslim, Abrar. "Optimisation of chlorine dosing for water disribution system using model-based predictive control". Thesis, Curtin University, 2007. http://hdl.handle.net/20.500.11937/459.
Texto completo da fonteResumo:
An ideal drinking water distribution system (DWDS) must supply safe drinking water with free chlorine residual (FCR) in the form of HOCI and OCIֿ at a required concentration level. Meanwhile the FCR is consumed in the bulk liquid phase and at the DWDS pipes wall as the result of chemical reactions. Because of these, an optimized chlorine dosing for the DWDS using model-based predictive control (MBPC) is developed through the steps of modelling the FCR transport along the main pipes of the DWDS, designing chlorine dosing and implementing a multiple-input multiple-output system control scheme in Matlab 7.0.1 software. Discrete time-space models (DTSM) that can be used to predict free chlorine residual (FCR) concentration along the pipes of the DWDS over time is developed using explicit finite difference method (EFDM). Simulations of the DTSM using step and rectangular pulse input show that the effect of water flow rate velocity is much stronger than the effect of chlorine effective diffusivity coefficient on the FCR distribution and decay process in the DWDS main pipes. Therefore, the FCR axial diffusion in single pipes of the DWDS can be neglected. Investigating the effect of injection time, initial chlorine distribution, and overall chlorine decay rate constant involved in the process have provided a thorough understanding of chlorination and the effectiveness of all the parameters. This study proposed a model-based chlorine dosing design (MBCDD) based on a conventional-optimum design process (CODP) (Aurora, 2004), which is created for uncertain water demand based on the DTSM simulation.In the MBCDD, the constraints must be met by designing distances between chlorine boosters and optimal value of the initial chlorine distribution in order to maintain the controlled variable (CV), i.e. FCR concentration with a certain degree of robustness to the variations of water flow rate. The MBCDD can cope with the simulated DWDS (SDWDS) with the conditions; the main pipe is 12 inch diameter size with the pipe length of 8.5 km, the first consumers taking the water from the point of 0.83 km, the assumed pipe wall chlorine decay rate constant of 0.45 m/day, and the value of chlorine overall decay rate constants follow Rosman's model (1994), by proposing a set of rules for selecting the locations for additional chlorine dosing boosters, and setting the optimal chlorine dosing concentrations for each booster in order to maintain a relatively even FCR distribution along the DWDS, which is robust against volumetric water supply velocity (VWS) variations. An example shows that by implementing this strategy, MBCDD can control the FCR along the 8.5 km main pipe of 12 inch diameter size with the VWS velocity from 0.2457 to 2.457 km/hr and with the assumed wall and bulk decay constants of 0.45 and 0.55 m/day, respectively. An adaptive chlorine dosing design (ACDD) as another CODP of chlorine dosing which has the same concept with the MBCDD without the rule of critical velocity is also proposed in this study. The ACDD objective is to obtain the optimum value of initial chlorine distribution for every single change in the VWS. Simulation of the ACDD on the SDWDS shows that the ACDD can maintain the FCR concentration within the required limit of 0.2-0.6 mg/1.To enable water quality modelling for studying the effectiveness of chlorine dosing and injection in the form of mass flow rate of pure gaseous chlorine as manipulated variable (MV), a multiple-input multiple-output (MIMO) system is developed in Simulink for Matlab 7.0.1 software by considering the disturbances of temperature and circuiting flow. The MIMO system can be used to design booster locations and distribution along a main pipe of the DWDS, to monitor the FCR concentration at the point just before injection (mixing) and between two boosters, and to implement feedback and open-loop control. This study also proposed a decentralized model-based control (DMBC) based on the MBCDD-ACDD and centralized model predictive control (CMPC) in order to optimize MV to control the CV along the main pipe of the DWDS in the MIMO system from the FCR concentration at just after the chlorine injection (CVin) to the FCR concentration (CVo) before the next chlorine injection with the constraints of 0.2-0.6 ppm for both the CVin and CVo. A comparison of the performances of decentralized PI (DPI) control, DMBC and CMPC, shows that the performances of the DMBC and CMPC in controlling the MIMO system are almost the same, and they both are significantly better than the DPI control performance. In brief, model-based predictive control (MBPC), in this case a decentralized model-based control (DMBC) and a centralized predictive control (CMPC), enable optimization of chlorine dosing for the DWDS.
29
Gada, Komal Kantilal. "Numerical analyses of passive and active flow control over a micro air vehicle with an optimized airfoil". Thesis, California State University, Long Beach, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=1606060.
Texto completo da fonteResumo:
Numerical investigations of an optimized thin airfoil with a passive and an active flow control device (riblets and rotary cylinder) have been performed. The objectives of the thesis were to investigate the tip vortices reduction using riblets and decrease in flow separation, using a rotary cylinder for improved lift-to-drag ratio. The investigations has application potentials in improving performances of Micro Air Vehicles (MAVs). The airfoil has a chord length of 19.66 cm and a span of 25 cm. with the free stream mean velocity was set at 20 m/s. The Reynolds number was calculated as 3 × 10 4. Investigations with base model of the airfoil have shown flow separation at approximately 85% chord length at an angle of attack of 17 degrees. For investigation using passive flow control device, i.e. riblets, investigations were performed for different radial sizes but at a fixed location. It was found that with 1 mm radial size riblet, the tip vortices were reduced by approximately 95%, as compared to the baseline model. Although negligible lift-to-drag improvement was seen, a faster dissipation rate in turbulent kinetic energy was observed. Furthermore, investigations were carried out using the active flow control device. The rotary cylinder with a 0.51 cm in diameter was placed slightly downstream of the location of flow separation, i.e. at x/c = 0.848. Investigations were performed at different cylinder's rotations, corresponding to different tangential velocities of being higher than, equal to and less than the free stream mean velocity. Results have shown approximately 10% improvement in lift to drag ratio when the tangential velocity is near the free stream mean velocity. Further investigation may include usage of the riblets and the rotary cylinder combined, to increase the stability as well as the lift-to-drag ratio of the MAVs.
30
Gettman, Douglas Mark 1971. "A multi-objective integrated large-scale optimized ramp metering control system for freeway/surface-street traffic management". Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282797.
Texto completo da fonteResumo:
This research, denoted MILOS (Multi-objective Integrated Large-scale Optimized ramp metering System) is a hierarchical structure for solution of the large-scale freeway management problem to address the key features of this problem (dynamic state changes, stochasticity, multi-dimensionality, unpredictability, partial-observability, and existence of multiple objectives). MILOS decomposes the freeway control problem into subproblems along temporal/spatial boundaries and is composed of three primary components: SPC-based anomaly detection and optimization scheduling, area-wide coordination layer, and predictive-cooperative real-time (PC-RT) optimization layer. The area-wide coordination component of the hierarchical control system considers the impact of queue growth on the adjacent interchanges in a quadratic programming optimization model with a multi-criterion objective function. The formulation of the area-wide optimization problem is augmented with overflow variables to guarantee a feasible solution. The nominal solution of the areawide coordination problem is then modified in real-time by the locally traffic-reactive, PC-RT algorithm based on a linear-program using a linearized dynamic difference equation implementation of the macroscopic FREFLO model. The PC-RT formulation pro-actively plans to utilize opportunities to disperse queues or hold back additional vehicles when freeway and ramp demand conditions are appropriate. The cost coefficients of this optimization problem is linked to the solution of the area-wide coordination problem by using information on the dual of the solution to the area-wide coordination problem. The optimization runs of the area-wide coordination problem and the PC-RT optimization problems at each ramp are scheduled by a demand/flow monitoring system based on statistical process control. A simulation experiment is executed to evaluate the MILOS hierarchical system against "no control", ADOT's current ramp metering policy, and an area-wide LP optimization problem resolved in 5-minute intervals on a small freeway network in the metropolitan Phoenix, AZ area. Three test cases are presented for a short "burst" of heavy-volume flows to all ramps, a 3-hour commuting peak, and a 3-hour commuting peak with a 30-minute incident occurring in the middle of the network. The performance results indicate that MILOS is able to reduce freeway travel time, increase freeway average speed, and improve recovery performance of the system when flow conditions become congested.
31
Muslim, Abrar. "Optimisation of chlorine dosing for water disribution system using model-based predictive control". Curtin University of Technology, Dept. of Chemical Engineering, 2007. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=21508.
Texto completo da fonteResumo:
An ideal drinking water distribution system (DWDS) must supply safe drinking water with free chlorine residual (FCR) in the form of HOCI and OCIֿ at a required concentration level. Meanwhile the FCR is consumed in the bulk liquid phase and at the DWDS pipes wall as the result of chemical reactions. Because of these, an optimized chlorine dosing for the DWDS using model-based predictive control (MBPC) is developed through the steps of modelling the FCR transport along the main pipes of the DWDS, designing chlorine dosing and implementing a multiple-input multiple-output system control scheme in Matlab 7.0.1 software. Discrete time-space models (DTSM) that can be used to predict free chlorine residual (FCR) concentration along the pipes of the DWDS over time is developed using explicit finite difference method (EFDM). Simulations of the DTSM using step and rectangular pulse input show that the effect of water flow rate velocity is much stronger than the effect of chlorine effective diffusivity coefficient on the FCR distribution and decay process in the DWDS main pipes. Therefore, the FCR axial diffusion in single pipes of the DWDS can be neglected. Investigating the effect of injection time, initial chlorine distribution, and overall chlorine decay rate constant involved in the process have provided a thorough understanding of chlorination and the effectiveness of all the parameters. This study proposed a model-based chlorine dosing design (MBCDD) based on a conventional-optimum design process (CODP) (Aurora, 2004), which is created for uncertain water demand based on the DTSM simulation.In the MBCDD, the constraints must be met by designing distances between chlorine boosters and optimal value of the initial chlorine distribution in order to maintain the controlled variable (CV), i.e. FCR concentration with a certain degree of robustness to the variations of water flow rate. The MBCDD can cope with the simulated DWDS (SDWDS) with the conditions; the main pipe is 12 inch diameter size with the pipe length of 8.5 km, the first consumers taking the water from the point of 0.83 km, the assumed pipe wall chlorine decay rate constant of 0.45 m/day, and the value of chlorine overall decay rate constants follow Rosman's model (1994), by proposing a set of rules for selecting the locations for additional chlorine dosing boosters, and setting the optimal chlorine dosing concentrations for each booster in order to maintain a relatively even FCR distribution along the DWDS, which is robust against volumetric water supply velocity (VWS) variations. An example shows that by implementing this strategy, MBCDD can control the FCR along the 8.5 km main pipe of 12 inch diameter size with the VWS velocity from 0.2457 to 2.457 km/hr and with the assumed wall and bulk decay constants of 0.45 and 0.55 m/day, respectively. An adaptive chlorine dosing design (ACDD) as another CODP of chlorine dosing which has the same concept with the MBCDD without the rule of critical velocity is also proposed in this study. The ACDD objective is to obtain the optimum value of initial chlorine distribution for every single change in the VWS. Simulation of the ACDD on the SDWDS shows that the ACDD can maintain the FCR concentration within the required limit of 0.2-0.6 mg/1.
To enable water quality modelling for studying the effectiveness of chlorine dosing and injection in the form of mass flow rate of pure gaseous chlorine as manipulated variable (MV), a multiple-input multiple-output (MIMO) system is developed in Simulink for Matlab 7.0.1 software by considering the disturbances of temperature and circuiting flow. The MIMO system can be used to design booster locations and distribution along a main pipe of the DWDS, to monitor the FCR concentration at the point just before injection (mixing) and between two boosters, and to implement feedback and open-loop control. This study also proposed a decentralized model-based control (DMBC) based on the MBCDD-ACDD and centralized model predictive control (CMPC) in order to optimize MV to control the CV along the main pipe of the DWDS in the MIMO system from the FCR concentration at just after the chlorine injection (CVin) to the FCR concentration (CVo) before the next chlorine injection with the constraints of 0.2-0.6 ppm for both the CVin and CVo. A comparison of the performances of decentralized PI (DPI) control, DMBC and CMPC, shows that the performances of the DMBC and CMPC in controlling the MIMO system are almost the same, and they both are significantly better than the DPI control performance. In brief, model-based predictive control (MBPC), in this case a decentralized model-based control (DMBC) and a centralized predictive control (CMPC), enable optimization of chlorine dosing for the DWDS.
32
Tao, Junbing [Verfasser]. "Half-cycle-sampled discrete model of series-parallel resonant converter with optimized modulation and its control design / Junbing Tao". Paderborn : Universitätsbibliothek, 2018. http://d-nb.info/1155236297/34.
Texto completo da fonte
33
Seitz, Timothy M. "Modeling and Robust Stability of Advanced, Distributed Control Systems". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1497201155817062.
Texto completo da fonte
34
Bai, Wenshuai. "DC Microgrid optimized energy management and real-time control of power systems for grid-connected and off-grid operating modes". Thesis, Compiègne, 2021. http://www.theses.fr/2021COMP2586.
Texto completo da fonteResumo:
Le travail de recherche de cette thèse se concentre sur l’élaboration de deux modes de fonctionnement du microréseau à savoir : mode connecté au réseau, mode hors réseau comprenant les modes îloté et isolé. Le problème de la défaillance du réseau en mode connecté au réseau et la faible fiabilité de l'alimentation électrique en mode hors réseau doivent être résolues. Ainsi, le but de cette thèse est de proposer un microréseau DC combinant à la fois les avantages du mode connecté au réseau et ceux du mode isolé. On obtient ainsi un microréseau DC qu’on peut qualifier de complet. Le microréseau DC complet contient les sources d'énergie renouvelables, le stockage et le réseau public, et les sources de secours sont utilisées pour réduire le délestage. Dans ce microréseau DC, un système de supervision est proposé dans le but de gérer le flux des puissances. La gestion de la puissance en temps réel dans la couche opérationnelle du système de supervision permet de maintenir l'équilibre de puissance. Dans la couche d'optimisation du système de supervision, l'optimisation journalière est proposée afin de minimiser le coût d'exploitation global. Les résultats de la simulation montrent que le microréseau DC complet peut minimiser les coûts d'exploitation. Ensuite, le système de supervision prend en compte l'efficacité dynamique du convertisseur pour résoudre le problème lié à la qualité de la puissance du microréseau qui peut être dégradée à cause de la tension instable du bus DC. Les résultats de la simulation montrent que la prise en compte de l'efficacité dynamique du convertisseur dans la couche opérationnelle du système de supervision permet de réduire les fluctuations de la tension du bus DC. En ce qui concerne l'importance de la prédiction PV pour l'optimisation de la veille, deux modèles de prédiction sont étudiés et comparés pour donner une puissance de prédiction PV précise. Les résultats montrent que les deux modèles ont presque les mêmes résultatsThis thesis focus on the research of the DC microgrid following two operation models: grid-connected mode, and off-grid mode including the islanded and isolated modes. The aim of this thesis is to propose a DC microgrid combining the advantages of the grid-connected or the off-grid mode, which named full DC microgrid. ln the full DC microgrid, the renewable energy sources, storage, and public grid are included, and the back-up sources also applied to reduce the load shedding. ln the full DC microgrid, a supervisory system is proposed to manage the power. The real-time power management in the operational layer of the supervisory system can keep the power balance. ln the optimization layer of the supervisory system, the day-ahead optimization is proposed to achieve the global minimal operation cost. The simulation results show that the full DC microgrid combines both advantages of the grid-connected and the off-grid mode to minimize the operating cost. Then, the supervisory system considers the dynamic efficiency of the converter to solve the problem that the power quality of the microgrid is degraded due to the unstable DC bus voltage caused by the inaccurate power control. The simulation results show that considering the dynamic efficiency of the converter in the operational layer of the supervisory system, the fluctuation of the DC bus voltage can be reduced. Regarding the importance of the PV prediction for the day-ahead optimization, two prediction modes are studied and compared to give a robust PV prediction power. The results are that the two models almost have the same results
35
Dong, Peng [Verfasser], Peter [Akademischer Betreuer] Tenberge e Xiangyang [Akademischer Betreuer] Xu. "Optimized shift control in automatic transmissions with respect to spontaneity, comfort, and lhift loads / Peng Dong. Gutachter: Peter Tenberge ; Xiangyang Xu". Bochum : Ruhr-Universität Bochum, 2015. http://d-nb.info/1079843795/34.
Texto completo da fonte
36
Abdayem, Anthony. "Stratégies de contrôle optimisées pour les convertisseurs multiniveaux modulaires (MMCs) connectés au réseau basse tension". Electronic Thesis or Diss., CY Cergy Paris Université, 2024. http://www.theses.fr/2024CYUN1301.
Texto completo da fonteResumo:
Le convertisseur modulaire multiniveaux (MMC) s'est imposé comme l'une des topologies les plus prometteuses pour les applications à moyenne et haute tension ainsi qu'à haute puissance. Récemment, il a également montré son potentiel pour des applications nécessitant de faibles tensions, appelées mini MMCs, qui contiennent un plus petit nombre de sous-modules par bras. Les caractéristiques clés des MMCs incluent la modularité, l'évolutivité en tension et en puissance, la tolérance aux pannes, le fonctionnement sans transformateur et des formes d'onde de sortie de haute qualité. Ces dernières années, de nombreuses études de recherche ont été menées pour aborder les défis techniques liés au fonctionnement, au contrôle et à la topologie des MMCs.L'une des applications les plus importantes des MMCs se trouve dans les systèmes connectés au réseau. Ces convertisseurs offrent l'avantage de réduire les harmoniques de courant et de tension sans avoir besoin de composants passifs encombrants. De plus, les MMCs se révèlent fiables grâce à leur structure, qui leur permet de continuer à fonctionner même en cas de défaillance d'un ou plusieurs interrupteurs de puissance. Cependant, leur contrôle est complexe en raison du grand nombre de configurations de commutation, nécessitant des algorithmes de contrôle sophistiqués. Cette thèse se concentre sur la mise en œuvre de techniques de contrôle avancées pour améliorer les performances des MMCs. Elle vise à explorer les MMCs, à améliorer les structures de puissance existantes pour de nouvelles applications, et à accroître l'efficacité et la fiabilité grâce à des techniques de conception de contrôle et de modulation. La recherche explore également le contrôle des MMCs à l'aide de méthodes de contrôle prédictif modélisées (MPC) innovantes.Plus précisément, cette thèse comprend une série d'études abordant les défis et améliorant les performances des MMCs dans diverses applications. Le premier ensemble d'études porte sur une nouvelle conception de contrôle pour les MMCs, permettant le contrôle séparé des tensions des condensateurs dans les bras supérieur et inférieur. La recherche cible également les MMCs monophasés, permettant le contrôle en conditions de déséquilibre de puissance entre les bras supérieur et inférieur. De plus, l'étude traite des techniques de modulation et d'équilibrage de tension. Une nouvelle technique de modulation, la technique de modulation intégrale (IM), une avancée par rapport à la technique de modulation au niveau le plus proche (NLM), est introduite. Un nouvel algorithme de tri est également proposé pour améliorer l'efficacité des MMCs en réduisant le nombre de commutations par seconde pour les techniques de modulation existantes telles que NLM, IM et PWM.La recherche s'étend également à l'exploitation en tolérance aux pannes dans les MMCs triphasés, proposant une méthode qui injecte des courants circulants harmoniques de fréquence et de courant continu pour maintenir le fonctionnement en cas de défaillance d'un bras. Une contribution importante consiste à développer un algorithme de contrôle prédictif modélisé à ensemble fini à horizon unique (FCS-MPC) pour les MMCs monophasés, qui surpasse les méthodes traditionnelles en termes de commutations, de qualité des formes d'onde de courant de réseau et de variation des tensions des condensateurs. Six algorithmes FCS-MPC pour les MMCs sont introduits, offrant des perspectives sur leurs performances par rapport à un schéma de contrôle en cascade classique. La thèse se termine par une configuration innovante pour un convertisseur à ponts en H en cascade (CHB), conçu pour l'intégration des énergies renouvelables, démontrant son efficacité à travers des simulationsThe modular multilevel converter (MMC) has emerged as one of the most promising topologies for medium- to high-voltage, high-power applications. Recently, it has also shown potential for applications requiring low voltages, known as mini MMCs, which contain a smaller number of submodules per arm. Key features of MMCs include modularity, voltage and power scalability, fault tolerance, transformer-less operation, and high-quality output waveforms. In recent years, numerous research studies have been conducted to address the technical challenges associated with MMC operation, control, and topology.One of the most significant applications for MMCs is in grid-connected systems. These converters offer the advantage of reducing current and voltage harmonics without the need for bulky passive components. Moreover, MMCs demonstrate reliability due to their structure, which enables them to continue operating even if one or more power switches fail. However, their control is complex due to the numerous switching configurations, necessitating sophisticated control algorithms. This thesis focuses on implementing advanced control techniques to enhance MMC performance. It aims to explore MMCs, improve existing power structures for novel applications, and increase efficiency and reliability through control design and modulation techniques. The research also investigates controlling MMCs using novel Model Predictive Control methods.Specifically, this thesis comprises a series of investigations addressing challenges and enhancing MMC performance across various applications. The first set of studies focuses on a new control design for MMCs, allowing separate control of capacitor voltages in the upper and lower arms. The research also targets single-phase MMCs, enabling control under unbalanced power conditions between the upper and lower arms. Additionally, the study addresses modulation and voltage balancing techniques. A new modulation technique, the Integral Modulation Technique, an advancement of the Nearest Level Modulation Technique, is introduced. A novel sorting algorithm is also proposed to enhance MMC efficiency by reducing the number of commutations per second for existing modulation techniques such as NLM, IM, and PWM.The research extends to fault-tolerant operation in three-phase MMCs, proposing a method that injects DC and frequency harmonic circulating currents to sustain operation in the event of a faulty arm. A significant contribution involves developing a single-horizon finite control set model predictive control (FCS-MPC) algorithm for single-phase MMCs, which outperforms traditional methods in terms of commutations, grid current waveform quality, and capacitor voltage variance. Six FCS-MPC algorithms for MMCs are introduced, offering insights into their performance compared to a classic cascaded control scheme. The thesis concludes with a novel configuration for a Cascaded H-Bridge (CHB) converter designed for renewable energy integration, demonstrating effectiveness through simulations.In summary, this thesis presents a comprehensive exploration of MMCs, addressing control challenges, fault tolerance, modulation techniques, and innovative configurations for renewable energy integration. The findings contribute to advancing MMC technologies in various applications
37
Diniz, Junior Walter Ferreira. "Controle de frequência para otimização da potência em um sistema de transmissão de energia sem fios". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/170927.
Texto completo da fonteResumo:
Nesse trabalho é apresentada uma estratégia de controle para manter a potência entregue a carga do link indutivo de um sistema de transferência de potência sem fios maximizada continuamente. Inicialmente, foi desenvolvido o modelo do link indutivo do sistema, de forma a encontrar uma expressão para a potência na carga. Em seguida, essa expressão foi analisada, buscando os pontos de potência máxima correspondentes às frequências ressonantes quando o fator de acoplamento magnético do link indutivo era variado. Assim, foi estabelecido um método para estimar esse fator de acoplamento k e consequentemente da indutância mútua M a partir do monitoramento direto da fase e do módulo da corrente de entrada do link e indireto da impedância de entrada. Portanto, a estratégia de controle proposta consiste em monitorar a corrente da fonte de entrada do link para estimar o fator de acoplamento magnético k e finalmente, sintonizar a fonte na frequência de ressonância associada ao coeficiente de acoplamento magnético pela função obtida fres(k). Os resultados experimentais mostraram que a estratégia proposta aumenta significativamente a potência entregue a carga em comparação a uma fonte de alimentação sintonizada em uma frequência fixa.A control strategy is presented in this work to maintain the power delivered to a load continuously maximized at the output of a wireless power transfer system. Initially, the inductive link model of the system was developed in order to find an expression for the power delivered to the load. Thus, the maximum power delivered to the load points were obtained experimentally while the magnetic coupling factor of the inductive link was varied and associated with the frequency of the source. The frequency and magnetic coupling variables were related to the maximum power on the load by a simple analytic function. Thus, a method has been established to estimate the coupling factor k and consequently the mutual inductance M by direct monitoring of the phase and the module of the input current of the link and indirect monitoring of the input impedance. Therefore, the proposed control strategy is to monitor the current of the input source of the link to estimate the magnetic coupling factor k and finally to tune the source at the resonance frequencies associated to the magnetic coupling coefficient by the obtained function fres(k). The experimental results showed that the proposed strategy increases significantly the power delivered to the load compared to a power source tuned at a fixed frequency.
38
ULPIANI, GIULIA. "Towards energy efficient, comfortable and climate resilient built environment: Development and application of smart, optimized and mitigation-oriented solutions". Doctoral thesis, Università Politecnica delle Marche, 2018. http://hdl.handle.net/11566/252561.
Texto completo da fonteResumo:
Questa tesi riporta una serie di attività di ricerca che indagano, sotto diversi aspetti spaziali e temporali, i temi di efficienza energetica, comfort e resilienza al cambiamento climatico relativi al settore edilizio. Il primo macroblocco tematico è incentrato sul design di logiche di controllo ottimizzate a servizio di svariati componenti edilizi, nella fattispecie: radiatori elettrici (logiche on-off, PID e fuzzy), finestre (algoritmi di comfort adattivi basati su qualità dell’aria e comfort termico), serre solari (ventilazione meccanica controllata a logica termoigrometrica) e ventilconvettori (modelli fuzzy e predittivi per la gestione degli apporti solari). Il secondo macroblocco indaga le ripercussioni del cambiamento climatico sulla performance energetica ed ergonomica dell’ambiente costruito, partendo dal singolo edificio fino a coinvolgere fenomenologie su scala urbana. Vengono dapprima presentati i risultati dello studio di quattro mesi condotto su territorio europeo nell’ambito dell’edizione 2015 del WISBA (Wienerberger Sustainable Building Academy): la resilienza di un edificio low-tech (rappresentato dal Building 2226, Austria) è investigata nel contesto delle condizioni climatiche attese nel 2050 per approdare ad una strategia di redesign anti obsolescenza prematura. In seguito, sono esposti e discussi i risultati di uno dei progetti di mitigazione dell’effetto isola di calore urbana, condotti in collaborazione con la University of New South Wales (Sydney, Australia): il caso limite rappresentato da una capitale tropicale (Darwin) è oggetto di monitoraggio, analisi, modellazione e sviluppo di contromisure specifiche. Nel complesso, l’intero percorso di ricerca mira a definire e testare su campo soluzioni ad elevato potenziale di risparmio energetico e comfort (indoor ed outdoor) tramite logiche smart e tecnologie orientate alla mitigazione dei fenomeni di surriscaldamento globale. Comun denominatore è l’inclusione di una robusta fase sperimentale.This thesis addresses a series of research activities spanning the different spatial and temporal aspects of energy efficiency, comfort and climate change resilience throughout diverse scales of the built environment. The first macro-topic deals with the design of optimized control logics of specific building components, notably: electric radiators (on-off, PID and fuzzy controllers), windows (indoor air quality and thermal comfort driven adaptive comfort algorithm), sunspaces (smartly controlled mechanical ventilation) and fan coil units (fuzzy and model-predictive logics to counteract overabundant solar gains). The second macro-topic focuses on how climate change phenomena impinge on the energetic and ergonomic performance of buildings and cities. Firstly, the outcomes of the four-month experience in Europe, as a member of the 2015 WISBA edition (Wienerberger Sustainable Building Academy), are presented: the low-tech concept of Building 2226 (Austria) was tested in the frame of the actual climatic conditions and in view of the expected climate change to come in 2050. A re-design strategy was developed to enhance its resilience. Secondly, the results of one of the Urban Heat Island (UHI) mitigation projects run during the last year in collaboration with the University of New South Wales (Sydney, Australia) are illustrated and discussed: the borderline case of a tropical city (Darwin, Northern Territory) was monitored, analysed, modelled and tackled by developing customized counterbalance measures. Indeed, the overarching aim of the whole research path is to provide and field-test smart, optimized and mitigation-oriented solutions towards more efficient and liveable indoor and outdoor spaces. Special focus was given to the collection of on-site validated data, by planning robust monitoring campaigns and properly selecting the sensor networks.
39
Nawaz, Shah. "Performance Study of ZigBee-based Green House Monitoring System". Thesis, Mittuniversitetet, Avdelningen för informations- och kommunikationssystem, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-24963.
Texto completo da fonteResumo:
Wireless Sensor Network (WSN) is an emerging multi-hop wireless network technology, and the greenhouse network monitoring system is one of the key applications of WSNs in which various parameters such as temperature, humidity, pressure and power can be monitored. Here, we aim to study the performance of a simulation-based greenhouse monitoring system. To design the greenhouse monitoring system based on WSN, we have used ZigBee-based devices (end devices, routers, coordinators, and actuators. Our proposed greenhouse monitoring network has been designed and simulated using the network simulator OPNET Modeller.The investigation is split into two; first, the aim is to find the optimal Transmit (Tx) power set out at sensor nodes and second, the focus is on studying how increasing the number of sensor nodes in the same greenhouse network will affect the overall network performance. ZigBee-based greenhouses corresponded to 4 network scenarios and are simulated using OPNET Modeller in which 22 different transmit (Tx) power (22 cases) in Scenario 1 is simulated, scenario 2, 3 and 4 estimated to 63, 126, 189 number of sensor nodes respectively. Investigating the performance of the greenhouse monitoring network performance metrics such as network load, throughput, packets sent/received and packets loss are considered to be evaluated under varied transmit (Tx) power and increasing number of sensor nodes. Out of the comprehensive studies concerning simulation results for 22 different transmit (Tx) power cases underlying the greenhouse monitoring network (Scenario1), it is found that packets sent/received and packets loss perform the best with the transmitted (Tx) power falling in a range of 0.9 mWatt to 1.0 mWatt while packet sent/received and packet loss are found to perform moderately with the transmitted (Tx) power values that lie in a range of 0.05 mWatt to 0.8 mWatt. Less than 0.05 mWatt and greater than 0.01 microWatt Tx power experience, the worst performance in terms of particularly packet dropped case. For instance, in the case of the packet dropped (not joined packet, i.e., generated at the application layer but not able to join the network due to lack of Tx power), with a Tx power of 0.01 mWatt, 384 packets dropped with a Tx power of 0.02 and 0.03 mWatt, 366 packets dropped, and with a Tx power of 0.04 and 0.05, 336 packet dropped.While increasing the number of sensor nodes, as in scenario 2, 3 and 4, dealing with sensor nodes 63, 126 and 189 correspondingly, the MAC load, MAC throughput, packet sent/received in scenario 2 are found to perform better than that of scenario 3 and scenario 4, while packet loss in scenarios 2, 3 and 4 appeared to be 15%, 12% and 83% correspondingly.
40
Yeomans, Kenneth Alfred. "Time optimised position control with motion constraints". Thesis, University of London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429193.
Texto completo da fonte
41
Wattrus, Mark. "Optimised combustion control for different diesel fuels". Master's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/5455.
Texto completo da fonte
42
Han, Shuang. "The Real-Time Multitask Threading Control". Thesis, Linköping University, Department of Electrical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10431.
Texto completo da fonteResumo:
In this master thesis, we design and implemented a super mode for multiple streaming signal processing applications, and got the timing budget based on Senior DSP processor. This work presented great opportunity to study the real-time system and firmware design knowledge on embedded system.
43
Yilmaz, Fikriye Nuray. "Space-time Discretization Of Optimal Control Of Burgers Equation Using Both Discretize-then-optimize And Optimize-then-discretize Approaches". Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613388/index.pdf.
Texto completo da fonteResumo:
Optimal control of PDEs has a crucial place in many parts of sciences and industry. Over the
last decade, there have been a great deal in, especially, control problems of elliptic problems.
Optimal control problems of Burgers equation that is as a simplifed model for turbulence
and in shock waves were recently investigated both theoretically and numerically. In this
thesis, we analyze the space-time simultaneous discretization of control problem for Burgers
equation. In literature, there have been two approaches for discretization of optimization
problems: optimize-then-discretize and discretize-then-optimize. In the first part, we follow
optimize-then-discretize appoproach. It is shown that both distributed and boundary time dependent
control problem can be transformed into an elliptic pde. Numerical results obtained
with adaptive and non-adaptive elliptic solvers of COMSOL Multiphysics are presented for
both the unconstrained and the control constrained cases. As for second part, we consider
discretize-then-optimize approach. Discrete adjoint concept is covered. Optimality conditions,
KKT-system, lead to a saadle point problem. We investigate the numerical treatment
for the obtained saddle point system. Both direct solvers and iterative methods are considered. For iterative mehods, preconditioners are needed. The structures of preconditioners for
both distributed and boundary control problems are covered. Additionally, an a priori error
analysis for the distributed control problem is given. We present the numerical results at the
end of each chapter.
44
Lee, Erik Ryan. "SET-WET: A Wetland Simulation Model to Optimize NPS Pollution Control". Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/35222.
Texto completo da fonteResumo:
A dynamic, compartmental, continuously stirred tank reactor, simulation model (SET-WET) was developed for design and evaluation of constructed wetlands in order to optimize non-point source (NPS) pollution control measures. The model simulates the hydrologic, nitrogen, carbon, dissolved oxygen, bacteria, vegetative, phosphorous and sediment cycles of a wetland system. Written in Fortran 77, SET-WET models both free water surface (FWS) and sub-surface flow (SSF) wetlands and is designed in a modular manner which gives the user the flexibility to decide which cycles and processes to model. SET-WET differs from many existing wetland models in that it uses a system's approach, and limits the assumptions made concerning the interactions of the various nutrient cycles in a wetland system. It accounts for carbon and nitrogen interactions, as well as effect of oxygen levels upon microbial growth. It also directly links microbial growth and death to the consumption and transformations of nutrients in the wetland system. Many previous models have accounted for these interactions with zero and first order rate equations that assume rates are dependent only on initial concentrations. The SET-WET model is intended to be utilized with an existing NPS hydrologic simulation model, such as ANSWERS or BASINS, but may also be used in situations where measured input data to the wetland are available.
The model was calibrated and validated using limited data collected at Benton, Kentucky. A non-parametric statistical analysis of the model's output indicated eight out of nine examined outflow predictions were not statistically different from the measured observations. Linear regression analysis showed that six out of nine examined parameters were statistically similar, and that within the expected operating range, all of the examined outflow parameters (9) were within the 95% confidence intervals of the regression lines. A sensitivity analysis showed the most significant input parameters to the model were those which directly affect bacterial growth and oxygen uptake and movement. The model was applied to a subwatershed in the Nomini Creek watershed located in Virginia. Two year simulations were completed for five separate wetland designs, with reductions in percentage of BOD5 (4%-45%), TSS (85%-100%), total nitrogen (42%-56%), and total phosphorous (38%-57%) comparable to levels reported by previous research.Master of Science
45
Ali, Mir Muddassir. "Optimized Control Of Steam Heating Coils". Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10283.
Texto completo da fonteResumo:
Steam has been widely used as the source of heating in commercial buildings and industries throughout the twentieth century. Even though contemporary designers have moved to hot water as the primary choice for heating, a large number of facilities still use steam for heating. Medical campuses with on-site steam generation and extensive distribution systems often serve a number of buildings designed prior to the mid-1980s. The steam is typically used for preheat as its high thermal content helps in heating the air faster and prevents coils from freezing in locations with extreme weather conditions during winter.
The present work provides a comprehensive description of the various types of steam heating systems, steam coils, and valves to facilitate the engineer's understanding of these steam systems.
A large percentage of the steam coils used in buildings are provided with medium pressure steam. Veterans Integrated Service Network and Army Medical Command Medical Facilities are examples which use medium pressure steam for heating. The current design manual for these medical facilities recommends steam at 30psig be provided to these coils. In certain cases although the steam heating coil is designed for a 5psig steam pressure, it is observed that higher pressure steam is supplied at the coil. A higher steam pressure may lead to excessive heating, system inefficiency due to increased heat loss, simultaneous heating and cooling, and increased maintenance cost.
Field experiments were conducted to evaluate the effect of lowering steam pressure on the system performance. A 16% reduction in temperature rise across the coil was found when the steam pressure in the coil was reduced from 15psig to 5psig. The rise in temperature with lower pressure steam was sufficient to prevent coil freeze-up even in the most severe weather conditions. Additional benefits of reduced steam pressure are reduced flash steam losses (flash steam is vapor or secondary steam formed when hot condensate from the coil is discharged into a lower pressure area, i.e., the condensate return line) and radiation losses, increased flow of air through the coil thereby reducing air stratification and reduced energy losses in the event of actuator failure.
The work also involved evaluating the existing control strategies for the steam heating system. New control strategies were developed and tested to address the short comings of existing sequences. Improved temperature control and occupant comfort; elimination of valve hunting and reduced energy consumption were benefits realized by implementing these measures.
46
Parsons, Matthew James. "Active vibration control using optimized piezoelectric topologies". 2007. http://etd.utk.edu/2007/ParsonsMatthew.pdf.
Texto completo da fonte
47
Lin, Jin-Yih, e 林金益. "Analysis of Optimized Deformation Control with Piezoelectric". Thesis, 1996. http://ndltd.ncl.edu.tw/handle/43260583100798903570.
Texto completo da fonteResumo:
碩士國立成功大學
機械工程研究所
84
Because of the special material properties, the direct pie- zoelectric effect and the converse piezoelectric effect, piezo- electric material can be used as sensors or actuators. The con- cept of using a network of piezoelectric sensors and actuators to form a self-monitoring and self-controlling "smart system" has recently drawn considerable interest. Consider a composite plate containing piezoceramics on both upper and bottom surface. Based on the piezoelectricity with consideration for the coupling between the strain field and the electric field, a finite element formulation is developed. An eight-node three- dimensional brick element is used, and three- dimensional incompatible modes are introduced to take into ac- count the bending behavior of the structure. This study uses this code to analyze the response of the structure subjected to different boudary conditions and loading conditions. As the sensor electrical output is known, an inverse method is imple- mented to determine the voltage that should be applied to the actuator to reduce the deflection to a minimum. This study in- cludes different optimization method in the inverse analysis, and provides a model of direct control. The results of this study show that the deflections resul- ting from thermal loading could be reduced from the inverse analysis. An active control algorithm could be obtained based on enough analytical data. The optimum voltage of actuator is easy to determine from the control algorithm.
48
練福人. "Study of optimized self-tuning adaptive control". Thesis, 1987. http://ndltd.ncl.edu.tw/handle/63027685777014823587.
Texto completo da fonte
49
Jiang, Anxiao (Andrew). "Optimized Network Data Storage and Topology Control". Thesis, 2004. https://thesis.library.caltech.edu/2137/1/phd.pdf.
Texto completo da fonteResumo:
This thesis addresses two key challenges for network data-storage systems: optimizing data placement for highly efficient and robust data access, and constructing network topologies that facilitate data transmission scalable to both network sizes and network dynamics. It focuses on two new topics — data placement using erasure-correcting codes, and topology control for nodes in normed spaces. The first topic generalizes traditional file-assignment problems, and has the distinct feature of interleavingly placing data in networks. The second topic emphasizes the construction of network topologies that achieve excellent global performance in comprehensive measurements, through purely local decisions on connectivity. The results of the thesis deepen the current understanding on these important and intriguing topics, and follow a mathematically rigorous approach.
50
Correia, Margarida. "Optimized trajectory planning and control for marine robots". Dissertação, 2013. http://hdl.handle.net/10216/75013.
Texto completo da fonte