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Harnessing demand flexibility to minimize cost, facilitate renewable integration, and provide ancillary servicesKefayati, Mahdi 18 September 2014 (has links)
Renewable energy is key to a sustainable future. However, the intermittency of most renewable sources and lack of sufficient storage in the current power grid means that reliable integration of significantly more renewables will be a challenging task. Moreover, increased integration of renewables not only increases uncertainty, but also reduces the fraction of traditional controllable generation capacity that is available to cope with supply-demand imbalances and uncertainties. Less traditional generation also means less rotating mass that provides very short term, yet very important, kinetic energy storage to the system and enables mitigation of the frequency drop subsequent to major contingencies but before controllable generation can increase production. Demand, on the other side, has been largely regarded as non-controllable and inelastic in the current setting. However, there is strong evidence that a considerable portion of the current and future demand, such as electric vehicle load, is flexible. That is, the instantaneous power delivered to it needs not to be bound to a specific trajectory. In this thesis, we focus on harnessing demand flexibility as a key to enabling more renewable integration and cost reduction. We start with a data driven analysis of the potential of flexible demands, particularly plug-in electric vehicle (PEV) load. We first show that, if left unmanaged, these loads can jeopardize grid reliability by exacerbating the peaks in the load profile and increasing the negative correlation of demand with wind energy production. Then, we propose a simple local policy with very limited information and minimal coordination that besides avoiding undesired effects, has the positive side-effect of substantially increasing the correlation of flexible demand with wind energy production. Such local policies could be readily implemented as modifications to existing "grid friendly" charging modes of plug-in electric vehicles. We then propose improved localized charging policies that counter balance intermittency by autonomously responding to frequency deviations from the nominal frequency and show that PEV load can offer a substantial amount of such ancillary services. Next, we consider the case where real-time prices are employed to provide incentives for demand response. We consider a flexible load under such a pricing scheme and obtain the optimal policy for responding to stochastic price signals to minimize the expected cost of energy. We show that this optimal policy follows a multi-threshold form and propose a recursive method to obtain these thresholds. We then extend our results to obtain optimal policies for simultaneous energy consumption and ancillary service provision by flexible loads as well as optimal policies for operation of storage assets under similar real-time stochastic prices. We prove that the optimal policy in all these cases admits a computationally efficient form. Moreover, we show that while optimal response to prices reduces energy costs, it will result in increased volatility in the aggregate demand which is undesirable. We then discuss how aggregation of flexible loads can take us a step further by transforming the loads to controllable assets that help maintain grid reliability by counterbalancing the intermittency due to renewables. We explore the value of load flexibility in the context of a restructured electricity market. To this end, we introduce a model that economically incentivizes the load to reveal its flexibility and provides cost-comfort trade-offs to the consumers. We establish the performance of our proposed model through evaluation of the price reductions that can be provided to the users compared to uncontrolled and uncoordinated consumption. We show that a key advantage of aggregation and coordination is provision of "regulation" to the system by load, which can account for a considerable price reduction. The proposed scheme is also capable of preventing distribution network overloads. Finally, we extend our flexible load coordination problem to a multi-settlement market setup and propose a stochastic programming approach in obtaining day-ahead market energy purchases and ancillary service sales. Our work demonstrates the potential of flexible loads in harnessing renewables by affecting the load patterns and providing mechanisms to mitigate the inherent intermittency of renewables in an economically efficient manner. / text
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Electrodiagnóstico: protocolo clínico y estandarización de Electrorretinografía (ERG)y Potenciales Evocados Visuales (PEV)en el perro beagleTorres Soriano, Desireé 02 December 2010 (has links)
La presente tesis se ha basado en conseguir dos objetivos fundamentales: diseñar un protocolo clínico de electrodiagnóstico para obtener el electrorretinograma (ERG) y los potenciales evocados visuales (PEV) en el perro beagle, y elaborar un estándar de los resultados para esta raza.Hemos establecido un protocolo clínico de electrodiagnóstico adaptado a nuestro equipo de diagnóstico, a las características de nuestros pacientes y, en general, a los recursos materiales que teníamos a nuestra disposición. De este modo, hemos conseguido realizar un protocolo de corta duración que nos permite evaluar la funcionalidad de las vías visuales del perro y detectar posibles anomalías.Concluimos que el protocolo que hemos establecido nos permite registrar adecuadamente el ERG y los PEV para el perro beagle, así como obtener resultados fiables y reproducibles que podemos considerar como estándar para esta raza canina y este equipo de electrodiagnóstico. / The aims of this thesis were firstly to design a clinical protocol for Electro, electroretinography (ERG) and visual evoked potential (VEP) in the Beagle dog and, secondly, to develop a performance standard for this breed. A clinical electrodiagnostic protocol adapted to our diagnostic equipment was established. This protocol considered the characteristics of the patients as well as the material resources at our Institution. This protocol allowed us to evaluate the functionality of the visual pathways in order to detect any anomalies. It can be concluded that the protocol established in this Thesis allows to record accurately the ERG and the VEP of Beagle dogs. Moreover, the results are reliable and reproducible and it could be considered as a good standard for this breed when these electrodiagnosis tools are employed.
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Desenvolvimento de um protótipo para monitoramento visual neurofisiológico intraoperatório.SILVA JÚNIOR, José Alberto Campos da. 29 June 2018 (has links)
Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-06-29T20:52:05Z
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Previous issue date: 2015-03-17 / O monitoramento neurofisiológico intraoperatório (MNIO) é uma metodologia que
agrega diferentes testes neurofisiológicos para uso simultâneo ou alternado num
mesmo paciente durante o procedimento cirúrgico, podendo avaliar a neurofisiologia
clínica em três campos: eletroencefalografia (EEG), eletromiografia (EMG) e
potenciais evocados (PE). O potencial evocado visual (PEV) permite avaliar a
função e integridade das estruturas corticais e subcorticais da via visual. Este exame
é realizado cotidianamente nos laboratórios de neurofisiologia, auxiliando o
esclarecimento de diferentes tipos de acometimentos da visão, seja por doença ou
traumatismos. Este trabalho tem como objetivo desenvolver um protótipo para o
monitoramento do PEV para avaliação da integridade das vias visuais durante
cirurgias neurofisiológicas. Foram realizadas várias etapas para o desenvolvimento
do protótipo do dispositivo ocular: simulação computacional; estudo das
características do olho humano; prototipagem rápida; caracterização do Biopolímero
ácido polilático (PLA) utilizado na prototipagem; desenvolvimento de um protótipo de
dispositivo ocular com sistema de iluminação integrado por LEDs a realização dos
testes de PEV com o protótipo desenvolvido. O PLA utilizado na prototipagem para o
desenvolvimento de partes do dispositivo ocular foi caracterizado por Difração de
Raios X (DRX), Espectroscopia na Região do Infravermelho por Transformada de
Fourier (FTIR), Calorimetria Exploratória Diferencial (DSC), Microscopia Ótica (MO),
Microscopia Eletrônica de Varredura (MEV) e Espectroscopia de Energia Dispersiva
(EDS), esses resultados mostraram que a prototipagem rápida não alterou as
propriedades físico-químicas e morfológicas do PLA. A simulação computacional
forneceu parâmetros adequados ao desenvolvimento do dispositivo ocular que
possibilitou uma maior eficiência na montagem do circuito eletrônico. Os resultados
dos testes de PEV foram realizados em diferentes pacientes, com os olhos fechados
e os mostraram-se promissores para uso em pacientes anestesiados. / Intraoperative neurophysiological monitoring (MNIO) is a methodology that combines
different neurophysiological tests for simultaneous or alternating in the same patient
during the surgical procedure can evaluate the clinical neurophysiology in three
fields: electroencephalography (EEG), electromyography (EMG) and evoked
potential (EP). The visual evoked potential (VEP) evaluates the function and integrity
of cortical and subcortical structures of the visual pathway. This test is performed
daily in neurophysiology laboratories, helping the clarifying of different types of bouts
vision, whether by disease or trauma. This study aimed to develop a prototype for
monitoring the VEP to assess the integrity of the visual pathways during
neurophysiological surgeries. Several steps were performed for the prototype ocular
device: computer simulation; study of the characteristics of the human eye; rapid
prototyping; Biopolymer characterization of polylactic acid (PLA) used in prototyping;
development of an ocular device prototype with integrated lighting system and VEP
achievement tests with the prototype. The PLA used in the prototype for the
development of parts of the device eye was characterized by X-ray diffraction (XRD),
Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry
(DSC), optical microscopy (OM), Scanning Electron Microscopy (SEM) and Energy
Dispersive Spectroscopy (EDS), these results showed that the rapid prototyping did
not change the physical-chemical and morphological PLA. The computer simulation
provides appropriate parameters for the development of ocular device that allowed
greater efficiency in the assembly of electronic circuit. The results of ENP tests were
performed in different patients, with closed eyes and have shown promise for use in
anesthetized patients.
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Le développement visuel et cognitif chez les enfants nés à terme ou prématurémentSayeur, Mélissa Sue 08 1900 (has links)
No description available.
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Market analysis for electric vehicle supply equipment : The case of China / Analys av marknaden för laddningsutrustning för elbilar : Fallet KinaBUSK, ANDREY, JOELSSON WARRENSTEIN, ARVID January 2014 (has links)
Personliga eldrivna fordon (EV) är ett nytt teknikområde som är på väg att uppnå stort momentum på flera av världens marknader. Eftersom branschen fortfarande ligger i sin linda finns det i nuläget inga tydliga strukturer, som gäller för alla marknader världen över, gällande relationerna mellan aktörer, vilket leder till osäkerheter när det kommer till att ta strategiska beslut. Uppdragsgivaren för denna studie är Hong Kong EV Power Ltd. (EV Power), en Hongkong-baserad leverantör av laddningsstationer för elbilar och relaterade tjänster, som har ambitionen att inträda marknaden på det kinesiska fastlandet inom den närmaste framtiden. Emellertid har EV Power ännu inte bestämt sig vilken stad de vill rikta in sig på i det första skedet. Denna avhandling ämnar formulera en modell som kan användas för att utvärdera och jämföra geografiska marknader med avseende på lämpligheten för ett marknadsinträde av en leverantör av laddningsstationer för elbilar. Dessutom kommer modellen testas på tre städer på kinas fastland (Peking, Shanghai och Shenzhen), med syfte att komma fram till vilken stad som är mest attraktiv för EV Power, samt att utvärdera modellens funktionsduglighet. Sist kommer resultaten från utvärderingen av de tre städerna att tjäna som utgångspunkten för en analys som ämnar ta fram framgångsfaktorer för ett marknadsinträde på kinas fastland. För att uppnå detta har fyra olika datainsamlingsmetoder använts: Först studerades teori, med syfte att få bakgrundskunskap likväl som att få förståelse för specifika faktorer som påverkar ett marknadsinträde som detta. För det andra observerades EV Powers nuvarande verksamhet i Hong Kong, i avsikt att förstå vad som har lett till den framgång som företaget upplevt på sin hemmamarknad. För det tredje intervjuades branschexperter för att få ett perspektiv på branschen som helhet. Sist samlades sekundär data kring de tre städerna in, för att kunna utvärdera de olika faktorerna som ingår i den framtagna modellen. Den slutgiltiga modellen består av fem faktorer som påverkar en stads attraktivitet för ett marknadsinträde av en leverantör av laddningsstationer för elbilar. De identifierade faktorerna är: ’Marknadens tillgänglighet’, ’Kortsiktig efterfrågan’, ’Förväntad marknadsandel’, ’Vinstmarginal’ och ’Långsiktig produktpotential’. Dessa faktorer är i sin tur indelade i subfaktorer som har sina egna uppsättningar av drivare. Efter att ha använt modellen för att utvärdera de tre städerna konstaterades det att Shanghai är den lämpligaste staden för ett marknadsinträde av EV Power, främst på grund av stadens dominans på marknaden för privatanvända elbilar och ett gynnsamt regelverk. Slutligen hittades tre framgångsfaktorer för ett sådant inträde: ’Fokusera på tjänster’, ’Bibehåll partner-relationer’ och ’Inträd tidigt’. / Personal electric vehicles (EV) is an emerging technology that has gained much momentum in several markets during the past decade, and China is currently one of the markets where the growth in EV sales is the highest. Since the industry is still in its infancy, there are currently no clear structures regarding the relationships between different actors that apply to all markets globally, leading to great uncertainty in strategic decisions. The commissioner of this study is Hong Kong EV Power Ltd. (EV Power), a producer of EV supply equipment (EVSE) and related services in Hong Kong, which aspires to enter the Chinese mainland in the near future. However, EV Power has yet to decide which city they want to target first. This thesis aims to formulate a model that can be used to evaluate and compare geographic markets for a market entry by an EVSE company. Furthermore, the model is tested on three cities in Mainland China (Beijing, Shanghai and Shenzhen), in order to derive the most attractive city for EV Power and to evaluate the adequacy of the model. Lastly, with the results from the city evaluation, as a point of departure, success factors for an entry into Mainland China by the commissioning company will be summarized. In order to achieve this objective, four distinct data collection methods have been used: First, theory was studied, in order to gain background knowledge as well as to understand specific factors that impact a market entry decision such as this. Second, EV Power’s current business in Hong Kong was observed, with a view to achieve an understanding of what has led the company to experience success in its home market. Third, Interviews with industry experts were conducted, so as to get a perspective on the industry as a whole. Fourth and last, secondary data for the different cities was collected, for the sake of evaluating them according to the developed model. The final model consists of five main factors that encompass the elements that influence a cities level of attractiveness for entry by an EV charging station supplier. The identified factors are: ‘Market accessibility’, ‘Short-term demand’, ‘Expected market share’, ‘Profit margin’, and ‘Long-term product potential’. These factors are in turn divided into sub factors that have their own set of drivers. Using the model to evaluate the cities, it was found that Shanghai is the most suitable city for a market entry by EV Power, mainly due to its dominance in the market for private EVs and a favourable regulatory environment. Finally, three main success factors, for such a market entry, were found: ‘Focus on services’, ‘Maintain partner relationships’, and ‘Enter early’.
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