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LUTTON, DEAN GREGORY. "SPATIAL RECLAMATION OVER TIME." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1054299047.
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Kim, Jinho. "Automatic Pitch Detection and Shifting of Musical Tones in Real Time." Thesis, Boston College, 2013. http://hdl.handle.net/2345/3057.
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Thesis advisor: Sergio AlvarezMusical notes are acoustic stimuli with specific properties that trigger a psychological perception of pitch. Pitch is directly associated with the fundamental frequency of a sound wave, which is typically the lowest frequency of a periodic waveform. Shifting the perceived pitch of a sound wave is most easily done by changing the playback speed, but this method warps some of the characteristics and changes the time scale. This thesis aims to accurately shift the pitch of musical notes while preserving its other characteristics, and it implements this in real time on an Android device. There are various methods of detecting and shifting pitch, but in the interests of simplicity, accuracy, and speed, a three step process is used. First, the fundamental pitch of a stable periodic section of the signal is found using the Yin pitch detection algorithm. Secondly, pitch marks that represent the local peak of energy are found, each spaced out by roughly one period (inverse of the fundamental frequency). Lastly, these marks are used in the Pitch Synchronous Overlap and Add (PSOLA) algorithm to generate a new signal with the desired fundamental frequency and similar acoustical characteristics to the original signal
Thesis (BS) — Boston College, 2013
Submitted to: Boston College. College of Arts and Sciences
Discipline: Computer Science Honors Program
Discipline: Computer Science
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Sheail, Philippa. "Time-shifting in the digital university : temporality and online distance education." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/15815.
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This thesis is situated in the context of the emergence of the ‘digital university’ in higher education. It addresses research questions which focus on organizational change, particularly on how a strategic shift to increase the provision of online distance education in a traditional, research-intensive, campus-focused university, affects the existing temporal and spatial practices of the institution. The research undertaken focuses on a UK university, during a period of strategic digital expansion in its postgraduate taught degree programmes, where funding is allocated by the institution to support a number of new courses and programmes, developed and designed to be available to students on a fully online basis. I take a narrative ethnographic research approach, which draws on interviews with university staff and students, alongside higher education policy and think-tank documents, and institutional websites. Particular attention is paid to the temporal aspects of each narrative account, in order to surface temporality over what I consider to be the spatial preoccupations of the literature and practices of online ‘distance’ education. Sustaining a critique of ‘anytime, anywhere’ accounts of online education, with a reminder that education takes place over time and in particular times and spaces, I draw on Sharma’s (2013) work on ‘critical time’, and particularly her notion of temporal ‘recalibration’ (2014), to think about complex temporal relations in the digital university. I go on to explore the idea of the digital university as transtemporal, as an alternative conceptualisation which opens up possibilities for imagining the university beyond its traditional temporal and spatial boundaries. I argue that understanding the dominant times and spaces of the university campus as central, and those accessing the campus in asynchronous or asymmetric ways as peripheral, may not just lead to spatially biased practices of distancing, but to a lack of recognition of emergent inequalities which are digitally reconfigured and potentially invisible. I conclude with some reflections on theoretical and methodological approaches to time and the digital in higher education and propose areas for future research.
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RAMACHANDRAN, GOWRI SANKAR. "Integration of enhanced slot-shifting in uc/os-II." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-12981.
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Urdea, Alexandra. "A stitch in time : searching for authenticity through shifting regimes of value in Romania." Thesis, Goldsmiths College (University of London), 2015. http://research.gold.ac.uk/12493/.
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This thesis deals with the role that material culture plays in the production of value and meaning through discourses of authenticity. It also follows how folk objects are mobilized in national ideologies, transmissions of personal and family memory, museological discourses and artistic acts. My research is centred around a collection of Romanian artefacts which travelled from Romania to the Horniman Museum in London in 1956. The project that I undertook was devised as a collaborative research project between Goldsmiths College and the Horniman Museum, in which two PhD researchers carried out a recontextualization of this collection. The objects had been collected from villages and other sources in the 1950s (a context of political and social change in Romania), then assembled into a collection and sent over to the Horniman Museum. My side of the project sought to bring out historical trajectories and the social life of material culture in the villages where the Horniman objects originated, and beyond. The objects on which my research focused, which I considered to be the counterparts of the ones stored at the Horniman, revealed a complex usage of the folk idiom and of material culture in Romania, expressed through debates around value, authenticity and history. My thesis is firstly concerned with the movement of things between different regimes of value, mapping out a network of spaces of cultural production where the folk idiom is relevant in Romania. The people I involved in my research continuously pointed out that the truly valuable thing I was seeking – the ‘authentic’ object – was to be found elsewhere. This promise of an ‘elsewhere’ has kept pushing my research further along: from one village to another; from village houses to the houses of culture, and then to museums; and from live folk performances to national television. The other concern of this thesis is with the places and moments where the circulation of objects is halted because their value is put into question. In the process, I reveal how people deal with the absence of what they define as ‘authentic’ objects. They either identify this absence as loss, and sometimes explain it through historical narratives and memories; at other times they alleviate it through performance. These different strategies entail different relationships with material culture, which I conceptualize as relationships between subject and object.
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Lee, Min J. "Chris Marker's work from WW II to May 68 and beyond : shifting realities in time and image." Thesis, University of Warwick, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412894.
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Higginson, Sarah L. "The rhythm of life is a powerful beat : demand response opportunities for time-shifting domestic electricity practices." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/16018.
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The 2008 Climate Change Act set legally-binding carbon reduction targets. Demand side management (DSM) includes energy use reduction and peak shaving and offers significant potential to reduce the amount of carbon used by the electricity grid. The demand side management (DSM) schemes that have tried to meet this challenge have been dominated by engineering-based approaches and so favour tools like automation (which aims to make shifting invisible) and pricing (which requires customer response) to shift demand. These approaches tend to focus on the tools for change and take little account of people and energy-use practices. This thesis argues that these approaches are limited and therefore unlikely to produce the level of response that will be needed in future. The thesis therefore investigates the potential for time-shifting domestic energy demand but takes a different angle by trying to understand how people use energy in their daily lives, whether this use can be shifted and some of the implications of shifting it. The centrepiece of the work is an empirical study of eleven households energy-use practices. The interdisciplinary methodology involved in-house observations, interviews, photographs, metered energy data and disruptive interventions. The data was collected in two phases. Initially, a twenty-four hour observation was carried out in each household to find out how energy was implicated in everyday practices. Next, a series of three challenges were carried out, aimed at assessing the implications of disrupting practices by time-shifting food preparation, laundry and work/ leisure. A practice theory approach is used to shift the focus of attention from appliances, tools for change, behaviour or even people, to practices. The central finding of this work is that practices were flexible. This finding is nuanced, in the light of the empirical research, by an extended discussion on the nature of practices; in particular, the relationship between practices and agency and the temporal-spatial locatedness of practices. The findings demonstrate that, in this study at least, expanding the range of demand response options was possible. The research suggests numerous possibilities for extending the potential of practices to shift in time and space, shift the energy used in practices or substitute practices for other non-energy-using practices, though there are no simple technological or behavioural fixes . More profoundly, however, the thesis concludes that infrastructures of provision , such as the electricity grid and the companies that run it, underpin and facilitate energy-use practices irrespective of the time of day and year. In this context technology-led demand response schemes may ultimately contribute to the problem they purport to solve. A more fundamental interrogation of demand and the infrastructures that serve it is therefore necessary and is almost entirely absent from the demand response debate.
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De, Lange Nico Louis. "Research into real-time energy management on old gold mines / N.L. de Lange." Thesis, North-West University, 2006. http://hdl.handle.net/10394/1345.
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Le, Trung. "Towards Sustainable Cloud Computing: Reducing Electricity Cost and Carbon Footprint for Cloud Data Centers through Geographical and Temporal Shifting of Workloads." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23082.
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Cloud Computing presents a novel way for businesses to procure their IT needs. Its elasticity and on-demand provisioning enables a shift from capital expenditures to operating expenses, giving businesses the technological agility they need to respond to an ever-changing marketplace. The rapid adoption of Cloud Computing, however, poses a unique challenge to Cloud providers—their already very large electricity bill and carbon footprint will get larger as they expand; managing both costs is therefore essential to their growth.
This thesis squarely addresses the above challenge. Recognizing the presence of Cloud data centers in multiple locations and the differences in electricity price and emission intensity among these locations and over time, we develop an optimization framework that couples workload distribution with time-varying signals on electricity price and emission intensity for financial and environmental benefits. The framework is comprised of an optimization model, an aggregate cost function, and 6 scheduling heuristics.
To evaluate cost savings, we run simulations with 5 data centers located across North America over a period of 81 days. We use historical data on electricity price, emission intensity, and workload collected from market operators and research data archives. We find that our framework can produce substantial cost savings, especially when workloads are distributed both geographically and temporally—up to 53.35% on electricity cost, or 29.13% on carbon cost, or 51.44% on electricity cost and 13.14% on carbon cost simultaneously.
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Abuzaid, Abdullah Ibrahim. "A Variation of Positioning Phase Change Materials (PCMs) Within Building Enclosures and Their Utilization Toward Thermal Performance." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/100612.
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Recently, buildings have been receiving more serious attention to help reduce global energy consumption. At the same time, thermal comfort has become an increasing concern for building occupants. Phase Change Materials (PCMs), which are capable of storing and releasing significant amounts of energy by melting and solidifying at a given temperature, are perceived as a promising opportunity for improving the thermal performance of buildings. This is because they use their thermophysical properties and latent heat while transforming state (or phase) as a feature for thermal energy storage systems to reduce overall energy demand, specifically during peaks hours, as well as to improve thermal comfort in buildings. This research aims to provide an overview of opportunities and challenges for the utilization of PCMs in the Architecture, Engineering, and Construction (AEC) sector, a broader understanding of specifically promising technologies, and a clarification of the effectiveness of different applications in building enclosures design especially in exterior walls. The research discusses how PCMs can be incorporated within building enclosures effectively to enhance building performance and improve thermal comfort while reducing heating and cooling energy consumption in buildings. The major objectives of the research include studying the properties of PCMs and their potential impact on building construction, clarifying PCMs selection criteria for building application, identifying the effectiveness of utilizing PCMs on saving energy, and evaluating the contribution of utilizing PCMs in building enclosures to thermal comfort. The research uses an exploratory quantitative approach that contains three main stages: 1) a systematic literature review, 2) laboratory experiments, and 3) validation to meet the goal of the research. Finally, by extrapolating results, the research ends with a practical assessment of application opportunities and how to effectively utilize PCMs in exterior walls of buildings.PHD
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Ovanfors, Anna. "Essays on nonlinear time series analysis and health economics." Doctoral thesis, Handelshögskolan i Stockholm, Ekonomisk Statistik (ES), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:hhs:diva-504.
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Boulter, Trent R. "Interactive TV News: A New Delivery Method for Broadcast Television News." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3751.
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This project looks at the development and use of a new delivery system for broadcast television news and its relation to the Uses and Gratifications and Push/Pull Theories. An in-home study of interactive news was conducted for two weeks, allowing people access to three local and 5 national newscasts via one interactive newscast. Users were able to access the interactive newscast whenever and however they wanted via their television or computer, as long as they had an internet connection. The results of this study show how the system was used,what specific actions were taken, and where the potential lies for further research.
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Almasarwah, Najat E. "Family Formation, Loading and Batch-Cyclic Flowshop Scheduling in Cellular Manufacturing Systems." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1503605158270554.
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Myska, Martin. "Possibilities with Stirling Engine and High Temperature Thermal Energy Storage in Multi-Energy Carrier System : An analysis of key factors influencing techno-economic perspective of Stirling engine and high-temperature thermal energy storage." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-53407.
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Small and medium-scale companies are trying to minimise their carbon footprint and improve their cash flow, renewable installations are increasing all over the Europe and are expected to do so in following years. However, their dependency on the weather cause pressure on matching the production with demand. An option how to challenge this problem is by using energy storage. The aim of this project is to determine techno-economic benefits of Stirling engine and high temperature thermal energy storage for installation in energy user system and identify key factors that affect the operation of such system. In order to determine these factors simulations in Matlab were conducted. The Matlab linear programming tool Optisolve using dual-simplex algorithm was used. The sensitivity analysis was conducted to test the energy system behaviour. Economic evaluation was done calculating discounted savings. From the results, it can be seen the significant benefit of SE-HT-TES installation is the increased self-consumption of the electricity from PV installation. While the self-consumption in cases when there was no energy storage implemented was around 67 % and in one case as low as 50 % with the SE-HT-TES the value has increased up to 100 %. Energy cost savings are 4.7 % of the cost for the original data set and go up to 6.2 % when simulation with load shift was executed. Simulations have also shown that energy customer with predictable energy demand pattern can achieve higher savings with the very same system. It was also confirmed that for users whose private renewable production does not match load potential savings are 30 % higher compared to the system where energy load peak is matching the PV production peak. Simulations also shown that the customers located in areas with higher electricity price volatility can benefit from such system greatly.
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PALLONE, Grégory. "DILATATION ET TRANSPOSITION SOUS CONTRAINTES PERCEPTIVES DES SIGNAUX AUDIO : APPLICATION AU TRANSFERT CINEMA-VIDEO." Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2003. http://tel.archives-ouvertes.fr/tel-00003363.
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La coexistence de deux formats : cinéma à 24 images/s et vidéo à25 images/s, implique l'accélération ou le ralentissement de la
bande-son lors du transfert d'un format vers l'autre. Ceci
provoque une modification temporelle du signal sonore, et par
conséquent une modification spectrale avec altération du timbre.
Les studios de post-production audiovisuelle souhaitent compenser
cet effet par l'application d'une transformation sonore adéquate.
L'objectif de ce travail est de fournir à l'industrie
audiovisuelle un système permettant de pallier la modification de
timbre engendrée par le changement de vitesse de lecture. Ce
système se compose d'une part d'un algorithme de traitement et
d'autre part d'une machine sur lequel il est implanté.
L'algorithme est conçu et développé pour répondre aux contraintes
liées à la qualité sonore et à la compatibilité multicanal. La
machine, baptisée HARMO, est conçue spécifiquement par la société
GENESIS sur la base de processeurs de signaux numériques, et doit
répondre à la contrainte de temps-réel. Cet aspect "valorisation"
conduit à intégrer dans le projet les contraintes de coût et de
délai de réalisation.
Un état de l'art basé sur une bibliographie quasi-exhaustive
aboutit à une classification originale des méthodes de dilatation
et de transposition existantes. Ceci nous amène à distinguer et à
étudier les méthodes classiques temporelles et fréquentielles, et
à introduire les méthodes temps-fréquence. Cette classification
est à la base de plusieurs méthodes innovantes :
1. deux méthodes temps-fréquence dont l'analyse est adaptée à l'audition,
2. deux méthodes couplées qui associent les avantages des méthodes temporelles et fréquentielles,
3. une méthode temporelle basée sur une amélioration des méthodes existantes.
Les algorithmes sont évalués grâce à une banque de sons-test
spécifiquement élaborée pour mettre en évidence les défauts
caractéristiques des algorithmes. Notre choix final s'est porté
sur l'approche temporelle, que nous optimisons par l'adjonction de
critères de segmentation basés sur l'autocorrélation normalisée et
la détection de transitoires. Cet algorithme s'intègre dans un
logiciel qui a été structuré pour un fonctionnement temps-réel et
multicanal sur le système HARMO.
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Amozegar, Mahdiyeh. "Tweeting in Times of Crisis: Shifting Personal Value Priorities in Corporate Communications and Impact on Consumer Engagement." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42416.
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Branding in the age of social media is thriving as companies continue to pour resources into digital campaigns in the hope of engaging their customers. The onset of the COVID- 19 pandemic boosted the importance of digital communication channels as physical distancing and lockdown measures disrupted business-as-usual and limited in-person interactions between firms and their customers. By implication, the global crisis pressed companies to deliver brand messages via online content to sustain or build customer relationships. This research focuses first on the branded content of corporate communications during the pandemic, focusing specifically on whether firms used the opportunity to showcase shared personal values. Second, we examine whether using value words in social media messages impacts customer engagement with these messages.
To address these related questions, we collected Twitter data from Fortune 500 firms posted between January 2020 until the end of August 2020, attending to 56,770 firm- initiated tweets (we excluded firm responses to customer messages). The first study examines the personal values expressed in the messages using the Personal Values Dictionary, based on Shalom Schwartz’s original ten-value typology. We argue that the unprompted expression of values in a text is a behavioural indicator of personal value priorities. The findings compare firms’ shifting value priorities over time and association with key events, namely the global pandemic declaration (March 11, 2020) and ensuing lockdowns and George Floyd’s murder (May 25, 2020), and BLM protests. We find that, indeed, companies did shift their value priorities. The second study assesses consumer response to the values companies put forth in their tweets, focusing on social media indicators of consumer engagement (CE), including the number of likes, retweets, replies, and CE correlation with the values promoted in the tweets. We observe a pre- post-crisis shift in CE with value-laden messages. Our findings provide managerial insights that can guide marketers to manage their social media content more efficiently and better align their marketing and branding efforts with customers' values in times of crisis.
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Oosthuizen, Nicolas Laurens. "Optimum water distribution between pumping stations of multiple mine shafts / Nicolas Laurens Oosthuizen." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9189.
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In 2011 the mining industry purchased 14.5% of the electrical energy generated by Eskom. During 2011 in South Africa, dewatering pump systems on gold mines were the fourth largest electrical energy consumer on South African mines therefor making dewatering pumps ideal candidates to generate significant financial savings. These savings can be realised by controlling time-of-use (TOU) schedules.
Previous studies concentrated on the impact of improving a pumping scheme of a single mineshaft. This dissertation will focus on the operations of a complete dewatering system consisting of multiple mineshafts. The case study will consist of a gold mine complex comprising of five different shafts - each with its own reticulation system – as well as the larger interconnected water reticulation system.
Various pumping options were investigated, simulated and verified. The interaction between shafts was determined when load-shifting was scheduled for all the shafts taking each shaft’s particular infrastructure into account. The underground dewatering system was automated and optimised based on the simulation results. Mine safety protocols were adhered to while optimal pump operational schedules were introduced.Thesis (MIng (Electrical and Electronic Engineering))--North-West University, Potchefstroom Campus, 2013.
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García, Aguirre Ana I. "An evaluation of cognitive deficits in a rat-model of Huntington's disease." Thesis, University of St Andrews, 2016. http://hdl.handle.net/10023/8827.
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The purpose of this thesis was to develop methodology by which treatments for the cognitive impairments in Huntington's disease (HD) could be tested. As such, the thesis focused mainly on evaluating rats with quinolinic acid (QA) lesions of the striatum, as this manipulation mimics some aspects of the neural damage in Huntington's disease, to try to identify cognitive deficits of HD resulting from cell loss in the striatum. In the first part (Chapters 3-5), the role of the striatum in implicit memory was investigated. Chapter 3 compared the performance of rats and humans on a reaction time task that evaluated implicit memory by presenting visual stimuli with differing probabilities which change over time. Although rats made higher percentage of incorrect responses and late errors, both groups showed a similar pattern of reaction times. Chapter 4 investigated whether implicit memory (the computation of probabilities to predict the location of a stimulus) was affected by selective blockade of dopaminergic transmission at the D1 or D2 receptors by SCH-23390 and raclopride, respectively. Reaction times were slower with SCH-23390 and raclopride, but only SCH-23390 reduced errors to the least probable target location. Chapter 5 used the same task to evaluate implicit memory in rats with QA lesions of the dorsomedial striatum (DMS). Implicit memory was not affected by lesions of the DMS, which suggested that once a task that requires implicit memory has been learned, the DMS was not involved in sustaining the performance of the task. The second part of this thesis (Chapter 6), explored the contribution of the DMS in habit formation. DMS lesioned rats did not show habitual responding, and were not impaired in learning a new goal-directed behaviour. The third part (Chapters 7 and 8), investigated the role of the dorsal striatum in reversal learning, attentional set-formation, and set-shifting. Dorsal striatum lesioned rats were not impaired in reversal learning, but had a diminished shift-cost, which suggested that dorsal striatum lesions disrupted the formation of attentional sets. These results showed that although QA lesions of the dorsal striatum mimic some aspects of the neural damage in HD, they did not result in the same cognitive deficits observed in patients with HD, at least using the tasks presented in this thesis. However, other animal models of HD could be evaluated using the different tasks presented in this thesis to continue the search of a reliable animal model of HD in which treatments for the disease could be evaluated.
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Judge, Sean Michael. "The Turn of the Tide, July 1942-February 1943: Shifting Strategic Initiative in the Pacific in World War II." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1310056182.
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Sanchez, Xitlaly. "Shifting Relations Suggest the Start of a “New Chapter” with Cuba—Or Do They?: Portrayal of Cuba in the New York Times, January 2014-July 2015." Scholarship @ Claremont, 2016. http://scholarship.claremont.edu/scripps_theses/843.
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The United States and Cuba announced that they would begin the process of restoring diplomatic relations in December 2014 after over fifty years of political disengagement. The shift in foreign policy produced a plethora of news articles. What do newspaper articles, in particular articles in The New York Times published between January 2014-July 2015, reveal about how, if at all, the representation of Cuba has changed since the two countries have initiated the process of restoring relations? How did the U.S. public react to this change? A qualitative content analysis of 117 articles from The New York Times reveal that the thaw in foreign relations with Cuba does not mean a significant shift in the portrayal of Cuba in U.S. newspapers. Cuba continues to be characterized as an undemocratic, unfree government.
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Zhang, Qiao. "Contribution à l'ordonnancement d'ateliers avec ressources de transports." Phd thesis, Université de Technologie de Belfort-Montbeliard, 2012. http://tel.archives-ouvertes.fr/tel-00909927.
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Nos travaux concernent l'étude d'une extension d'un problème d'ordonnancement bien connu sous l'appellation job shop. Nous appelons cette extension le General Flexible Job Shop Scheduling Problem (GFJSSP). Celui-ci se rencontre dans différents types d'ateliers ayant comme caractéristique commune d'être soumis à des contraintes dues à des ressources de transport. Le GFJSSP se caractérise par l'intégration de machines et robots flexibles. Le terme General induit par ailleurs la présence de robots dont la capacité est supposée unitaire dans notre étude, des temps opératoires bornés, et la possibilité de prise en compte d'emplacements de stockage spécifiques. Après avoir défini l'atelier et le problème correspondant à cette extension, nous avons proposé deux modélisations du GFJSSP ainsi défini : une première modélisation mathématique linéaire, et une modélisation graphique, qui correspond à une généralisation du graphe disjonctif couramment utilisé pour les problèmes de job shop. Nous avons ensuite abordé la résolution suivant deux étapes : tout d'abord en nous focalisant sur l'aspect séquencement des tâches de traitement et de transport, pour lequel nous avons élaboré deux méthodes heuristiques (de type Tabou et basée sur une procédure de shifting bottleneck améliorée) ; puis en intégrant dans un deuxième temps la problématique de l'affectation induite par la flexibilité de certaines ressources. Pour cette dernière étape, nous avons combiné les méthodes précédentes avec un algorithme génétique. L'algorithme hybride obtenu nous permet de résoudre des instances de la littérature correspondant à divers cas spécifiques, avec des résultats assez proches des meilleures méthodes dédiées. A termes, il pourrait être intégré dans un système d'aide à la décision général qui s'affranchirait de la phase d'identification préalable du type de job shop considéré, et serait adapté à la résolution de nombreux cas (avec ou sans problème d'affectation, temps de traitement fixes ou bornés, avec ou sans stockage, etc..).
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Hsieh, Bing Heng, and 謝秉衡. "The Real Time Processing of Audio Pitch Shifting." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/xnf333.
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碩士長庚大學
電機工程學系
104
This paper focuses on audio signal to process of pitch shifting in frequency domain. When the pitch is raised, the frequency spectrum will expand. On the contrary, the frequency spectrum will compression when the pitch is lowered. This paper uses the expanding or compression frequency spectrum, which obtain by using linear interpolation method, to achieve the pitch-shifting effect. The complexity of two methods which we proposed is lower than that of Phase Vocoder. The two methods are very simple and have a nice performance. Besides, this paper presents theoretical investigation and analysis for the method.
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Chiang, Tai-ying, and 江岱穎. "Time Priority Based Resource Leveling for Shifting Bottleneck Procedure." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/68428956325040824506.
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碩士國立成功大學
工業與資訊管理學系碩博士班
95
Solutions for Job Shop Scheduling problems are in most demand in production systems. Job Shop has high production variability and usually applies to special products. It is difficult to solve the scheduling problems because of a variety of products passed through different sequences of machines and operations. The Shifting Bottleneck Procedure is one of effective heuristic algorithms to resolve Job Shop Scheduling problems. The main purpose of this research is to obtain minimum makespan for Job Shop Scheduling problems using Modified Shifting Bottleneck Procedure and Resource Leveling technique, combined with several time-priority indexes. The study shows that this approach can improve scheduling results.
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Yang, Hung-Chang, and 楊宏昌. "An Adaptive Live Broadcasting Scheme for Time-Shifting Playback." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/05894702657927900217.
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碩士國立中央大學
資訊工程研究所
89
In the recent year, the developments in computer and communication technologies have made it possible to provide interactive multimedia services. More and more households are connecting to the Internet to get popular information and hot news in addition to newspaper, magazine, radio and TV. However, real-time information is the hottest one that people want to access. People could connect to Internet to watch the live video immediately. But it is impractical in the near future due to the video server has to prepare or reserve a huge bandwidth. Therefore, how to use the limited bandwidth to accommodate as many users’ requests as possible is vital. Since many people want to watch the same hot live video, the required bandwidth of live video is possible to be shared. If we increase the probability of sharing the bandwidth for the same video and using local disk to buffer posterior video data, we can reduce the require bandwidth of the video server. However, the characteristics of live video are playing/recording in real-time and its production rate is equal to playback rate. We cannot pre-fetch the video and store them in the disk of video server beforehand. Furthermore, the clients cannot fast-download the posterior portion of video. Many schemes are proposed to reduce the bandwidth requirements for stored popular videos, but they cannot be used to support live video broadcast perfectly. Herein, we propose a new broadcasting scheme, called Adaptive Live Broadcasting (ALB) scheme, which supports time-shifting playback and perform well over a wide range of request arrival rates. Time-shifting playback can be classified into two playback types: the first one is it allows the late user to watch an on-going live video from the beginning while recording is still in progress. Another one is its timeliness is very important. The broadcast contents per hour of the live video are different. The older news would be abandoned, and the recent news would be added.
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Chen, Yi-An, and 陳奕安. "The Design and Implementation of Time-Shifting Mechanism for Live Streaming Multimedia." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/58597115781305566630.
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碩士朝陽科技大學
資訊工程系碩士班
95
Unlike Video on Demand (VOD) which is able to pause at any time, live streaming multimedia must play a video without interruption. This research focuses on the transmission of live streaming multimedia and develops a Continuing Service System (CSS) in the IP router, generally used in the family, to complete the “Time-Shifting” mechanism. The purpose of this research breaks the limitations of time and space in the streaming transmission and provides users with a continuing service of viewing all live streaming multimedia programs no matter whether they leave temporally or have to change the watching location. From the point view of “Humanistic”, we have considered to meet the requirement of the “practicability” and “suitability”: For the Practicability consideration, the IP router, that is a broadband Internet Gateway Router, is the entry to home network, it is the key element that cost downs to increase its additional value. For the Suitability consideration, the user does not need to change the use habit of the original multimedia player.
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Purwadi and 蒲瓦帝. "Improvement of Shifting Time Waveform Induced CMOS Latch-Up in Bootstrapping Application." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/48931988070212076376.
Full textAbstract:
碩士亞洲大學
資訊工程學系碩士班
100
In this thesis, latch-up mechanisms of the complementary-metal-oxide-semiconductor (CMOS) in bootstrapping technique applied to DC/DC buck converter circuit has been clearly investigated by two dimensional (2D) TCAD simulations. The shifting times of input signal waveforms were demonstrated to be the key factor to induce the CMOS latch-up due to the triggering of parasitic bipolar junction transistors (BJTs) in the CMOS bootstrapping application. In addition, the free latch-up design window suggests that both of the larger rise time and longer shifting times of input signal waveforms will provide a larger safety operation region for circuit design engineers in this work. Moreover, the latch up design window improvement is investigated by increasing distance anode to cathode of parasitic SCR or source to bulk of NMOS. In addition, decreasing beta current gain is explained well as the main reason free latch-up design windows improvement.
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Kang, Jia-Lun, and 康嘉倫. "On a Wire Bonding Machine's Shifting Production Problem in Consideration of the Time Value." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/58644885186367780697.
Full textAbstract:
碩士中原大學
工業與系統工程研究所
101
The semiconductor industry in Taiwan has achieved excellent performance in the past decades. Gartner’s statistics in April 2013 found that three of the top five global packaging and testing companies are from Taiwan, including ASE, SPIL, and PTI, thus proving the important role of Taiwan in the global IC packaging industry. In the IC packaging process, the wire bonding machine is often a bottleneck, and also requires a high investment, at approximately 50% of the equipment Investment. Thus, this study focuses on wire bonding machines production problems in the IC packaging process. Based on situational interview, this study has identified three key control modules, namely, the capillary tip under the pressure force control module, the lead frame temperature control module, and the thermosonic bonding power control module, which affect machine changes and create defect key modules, and are responsible for 90% of the occurring defect products. In addition to wire bonding machine problems, this study considers time value and the inflation to build a mathematical model, where the exponential function terms are replaced by the MacLaurin Series, and also identifies the math properties and a range of solutions to get an approximation solution. Its objective is to determine the optimal production cycle time and then to obtain the minimal total cost. Finally, this study applies the bisection method with practical data to justify the approximated solution’s quality and explores the managerial insights from observed outputs through the changes of various parameters. The solution approach is expected able to serve as a reference for practical decision-making to reach the minimized total cost purpose.
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"Time-series indexing for efficient searching with scaling and shifting transformations in advanced database systems." 1999. http://library.cuhk.edu.hk/record=b5890045.
Full textAbstract:
by Chu, Kam Wing.Thesis (M.Phil.)--Chinese University of Hong Kong, 1999.
Includes bibliographical references (leaves 67-73).
Abstracts in English and Chinese.
Abstract --- p.i
Acknowledgments --- p.iv
Chapter 1 --- Introduction --- p.1
Chapter 2 --- Related Work --- p.6
Chapter 3 --- Time-Series Searching with Scaling and Shifting --- p.12
Chapter 3.1 --- Problem Statement --- p.15
Chapter 3.2 --- Preliminary --- p.16
Chapter 3.3 --- Geometrical View of the Problem --- p.18
Chapter 3.3.1 --- Scale-Shift Transformation --- p.21
Chapter 3.3.2 --- Determine Scaling Factor and Shifting Offset --- p.24
Chapter 3.4 --- Algorithm --- p.25
Chapter 3.4.1 --- MBR Penetration --- p.26
Chapter 3.4.2 --- Long Sequence --- p.28
Chapter 3.5 --- Implementation Details --- p.29
Chapter 3.5.1 --- MBR Penetration Checking --- p.29
Chapter 3.5.2 --- Dimension Reduction --- p.32
Chapter 3.6 --- Experimental Results --- p.34
Chapter 4 --- Metric Space Indexing for Multimedia Databases --- p.38
Chapter 4.1 --- Preliminaries --- p.39
Chapter 4.1.1 --- M-tree --- p.39
Chapter 4.1.2 --- Range Queries --- p.41
Chapter 4.1.3 --- Nearest Neighbor Queries --- p.44
Chapter 4.2 --- Nearest Neighbor Search by dmin Only --- p.46
Chapter 4.3 --- Analysis --- p.50
Chapter 4.3.1 --- Critical Factor dmin --- p.52
Chapter 4.4 --- Multiple Bounding Regions --- p.54
Chapter 4.4.1 --- Computing Multiple Bounding Regions --- p.56
Chapter 4.4.2 --- New Insert Strategy --- p.58
Chapter 4.5 --- Experimental Results --- p.58
Chapter 5 --- Conclusions --- p.64
Chapter 5.1 --- Time-Series Searching with Scaling and Shifting --- p.64
Chapter 5.2 --- Metric Space Indexing --- p.65
Bibliography --- p.67
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Lu, Yen-Chang, and 呂彥樟. "Improving On Time Delivery in a Shifting Bottleneck Production Line-A Pre-recorded Disk Production Example." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/53071401140748007376.
Full textAbstract:
碩士華梵大學
工業工程與經營資訊學系碩士班
97
The seasonality factor has strong impact to the market demand of the pre-recorded CD industry. The transition between seasons creates a significant difference in demand pattern that in term causes the bottleneck floating between workstations, an inevitable situation that makes the effort of managing such production is even more difficult. In order to reduce the risk of late delivery, the research developed a small order strategy, a large order strategy and a mixed order strategy based on the demand patterns of the off-peak demand season, peak demand season, and the transition period between these two seasons, respectively. The small order strategy increases the utilization of the molding station through outsourcing and capacity searching. The large order strategy solves the order delay problem by making extra copy of the masters whenever needed. The mixed strategy combines the two strategies and applies the characteristic from the parallel machines to improve the shifting bottleneck problem. The results indicate that the three methods developed in this research do have good performance in the on-time delivery, the average flow time, the average lateness, and the number of tardy jobs in their intended settings.
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Liu, Chien-Wei, and 劉兼維. "Developing a High-Speed Electronic Speckle Pattern Interferometer:Experimental demonstration of time-stepping quadrature phase shifting method." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/17094298396297255284.
Full textAbstract:
碩士國立臺灣大學
工程科學及海洋工程學研究所
94
After many years development and improvement, microscopy has been getting to be one of the most important precision metrology techniques. To meet the demand of the rapidly advanced micro-electro-mechanical system and nanotechnology, many instruments were invented by further integrating microscope into their systems. In the field of full-field measurement, high-speed electronic speckle pattern interferometry (ESPI) developed using high-speed CCD camera was first developed in 1978. Phase shifting interferometry was used to transform the speckle intensity information into the more desirable phase information. However, it is necessary to introduce a phase shifting device in the reference arm if phase shifting interferometry is to be implemented. However, adding phase shifting device significantly increases the system cost. Moreover, the measurement precision suffers due to the errors induced by the phase shifting device. For example, hysteresis of piezoceramic actuator can introduce errors in the range of several micrometers. The goal of this research is thus to develop a new ESPI system that can measure full-field and dynamic vibrations up to nanometer resolutions without the need to adopt the traditionally used phase shifting device. With the development of an innovative optical design and the associated signal-processing algorithm, phase shifting device is removed successfully from the optical system. Alignment and other related alignment and operational procedures is thus greatly simplified. In this dissertation, high-speed CCD camera was used as the image system. An eight-wave retardation plate was added within the optical path to remove the phase shifting device. By means of short exposure time and precise time sequency control, transient information in a series of time scales could be obtained successfully. In image processing part of ESPI, time stepping quadrature phase shifting method, direct correlation method, noise reduction median filter, and path-independent phase unwrapping method were all integrated to reconstruct surface profile of specimen. By demonstrating the feasibility of time stepping quadrature phase shifting method, we successfully remove the phase shifting device from the system and basically eliminated the errors induced by the inaccurate phase modulation. With regards to the experimental verifications, the electronic speckle image processing interface was developed by LabVIEW and the feasibility of the newly proposed optical configuration is demonstrated by optical simulation software. Finally, the feasibility of time stepping quadrature phase shifting method is verified experimentally.
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Chong-Ding, Liu, and 劉崇鼎. "Shifting trace of time and space－A discussion of Liu Chong-Ding''s creation." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/64w3m2.
Full textAbstract:
碩士長榮大學
美術系(所)
98
In the period of time, from enlisting as a soldier to returning to the campus again, I start to realize I am touching the complex and multifaceted world, and also intensively pay attention to the society I live in. With the advance of technology and mass media, it is fairly easy to attend and follow the social trend through the Internet and televisions. In the early days, people lived in the relatively closed and conservative society, often concerning with their own life only. In contrast with the past, due to accessed information, combining with open and almost uninhibited society, the topics people can talk become wider and hotter. Topics from political criticism to negative eroticism are able to become popular. Recently a great part of the reason of changing status of Taiwan links with the political environment, especially cross-strait relations. For instance, visiting from politicians and tourists of Mainland China easily causes social events, affecting people''s sensitive nerve. The author tried to integrate into the context of these events, with the way of painting, reproducing and recording the historic scene. Hope that through this concern around the surrounding social phenomena, people can enhance the understanding the land we grew up in, such as politics, economy and living environment, further to be self-vigilant. This study comprised of six chapters. Introduction of chapter one demonstrated the motivation and purpose of present study, which was a summary toward social phenomena that the researcher had experienced during 2008 to 2010.Literature review and graphic analysis of chapter two portrayed assortment of relative literature works that sociology was applied, an inevitable theory proposed by historic dialectician, Hegel, which connected art and social phenomena as mutual development. Objects and practices of present study of chapter three regarded major social events happened since 2008. And we quote the artists and paints in art history they are related to this topic to prove our research. Techniques in art performances of chapter four was attempted to probe into a further context, a possibility of aesthetic violence. The researcher also briefly described the material, procedures and techniques of scene composing. Chapter five included work explanation and analysis .In conclusion of chapter six, The researcher hoped that this study could look into various groups and situation in Taiwanese society in a view of social concern to draw more attention toward surrounding environment and soul promotion in Taiwan. Key words: realism, social phenomena, aesthetic violence, symbolism, ugly
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Han, Shin-Ru, and 韓欣儒. "Application of Time-domain Pitch Synchronous Overlap and Add to Simulate the Frequency Shifting Function in Hearing Aids." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/12119946682085963209.
Full textAbstract:
碩士國立臺灣大學
工程科學及海洋工程學研究所
98
Many listeners with medium-severe hearing loss present audiograms with high frequency loss descending profiles. These patients can resolve spectral cues normally for lower frequency signals, but they often show less ability to use high frequency information. Frequency shifting hearing aids, which transpose the high frequency components of input sounds to the low frequency region, are known to be beneficial for sensorineural severe-to-profound hearing impaired listeners with residual hearing in the low frequency region. Early studies with frequency-lowering technology reported mostly unfavorable results, and the devices never gained clinical popularity. However, as hearing aid technology becomes ever more sophisticated, it is appropriate to reconsider whether frequency-lowering hearing aids should be an amplification choice in those with high-frequency hearing loss. Slow playback is the earliest method of implementing frequency-lowering in hearing aids, while resulting in longer output signals. This can cause the input and output signals to be desynchronized in time. In this research, time-scale modification and slow playback are combined to simulate frequency-shifted speech. Time-scale modification can change signal length without changing the spectrum characters and let output signal the same length with input. The time-scaling algorithms used in this paper are LSEE-MSTFTM, SOLA and TD-PSOLA. In the analysis process, the time frequency analysis diagram and the pitch contour diagram are utilized to compare simulation result. G&L method has more steady result, but it costs too much time. SOLA method is faster while the frame length will affect the output result. For the affricatives in speech ,TD-PSOLA method tend to has incorrect speech length, On the whole, TD-PSOLA method has the best result in three methods.
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Huang, Sheng-Min, and 黃聖閔. "A real-time temperature monitoring system of non-invasive focused ultrasound thermal ablation base on echo shifting effect." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/26232645712852024681.
Full textAbstract:
碩士長庚大學
電機工程研究所
95
Focused ultrasound technology has been examined to be capable of successfully performing noninvasively thermally ablate deep-seated biological tissues. When steering the focused energy at the specific target in biological tissues, the energy can steer concentrated energy to thermally ablate tissues, with the accumulated energy along the beam path is small and the unwanted damage in the intervening tissues can be avoid. Nowadays, a number of ultrasound-imaging guided focused ultrasound thermal therapy systems have been developed, which all utilize the echogeneity change from the B-mode ultrasonic imaging to predict the produced lesions. However, many previous reviews point out the discrepancy between the echogeneity change and the ablative region, indicating that temperature monitoring is essential to guarantee the treatment quality during the thermally ablative process. The purpose of this study is to design a real-time pulse/echo system to perform 1-D real-time temperature estimation integrating with the focused ultrasound system. In this study, a modified echo-time shifting algorithm was developed to calculate the corresponding phase shift from echo signal, which correlates with the instantaneous temperature change during heating. Phantom experiments were performed, and multiple point temperatures were measured from thermocouples to verify and calibrate the estimated data. The integrated system includes heating control, temperature estimation operating on a designed graphical user interface (GUI). Results show that our developed algorithm is capable of performing 1-D real-time temperature estimation. This provides useful information for further temperature estimation form clinical ultrasonic imaging system.
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Huang, Tsung-Yen, and 黃宗彥. "Development of a surface-plasmon resonance phase modulation image detection system based on Time-stepped Quadrature Phase Shifting Method." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/92938168557221419357.
Full textAbstract:
碩士國立臺灣海洋大學
機械與機電工程學系
99
Applications of optical measurement methods for bio-interaction detection have become very popular because of the great progress in optical components and techniques. Surface plasmon reasonance (SPR) biosensor has the advantages of label free and high sensitivity and it can detect the biomolecular interaction real-time. However, the sensitivity of intensity modulated SPR technique is not good enough to analyze biomolecular interaction for small biomolecules in low concentration. In this research work, an image SPR system adopting the phase interrogation was developed because the sensitivity of phase interrogation is the best compared with the intensity, angle, and wavelength interrogation. Since the resolution and precision of the phase interrogation SPR system is decided by the value of phase shift and the environment disturbance, the time-stepped quadrature phase shifting method has been utilized in the system. Time-stepped quadrature phase shifting method is realized by using the 1/8 wave plate and CCD (charge coupled device) in the opto-mechanical system. This can eliminate the error induced by the mechanical phase shifting device and the environment disturbance. Therefore, the bio-detecting system developed in this research work was implemented and was a real time image phase interrogation SPR detecting system. With regards to the experimental verifications, time-stepped quadrature phase shifting image processing algorithm was developed by LabVIEW program. Finally, the feasibility of time stepping quadrature phase shifting method was verified experimentally and successfully adopted into the image phase interrogation SPR detecting system
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Chen, JAu-Yu, and 陳昭宇. "Developing a High-Speed Electronic Speckle Pattern Interferometer: Innovation from Integrating Laser Doppler Interferometry and Time-stepped Phase Shifting Method." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/33884288111300750176.
Full textAbstract:
碩士國立臺灣大學
應用力學研究所
93
With the rapid advancement of nanotechnology, many industries have focused their research efforts to products of miniature size. It is to be noted that high-precision metrology is the driving force that propels miniature product forward. To further advance this line of research, there is an imminent need to develop a metrology system that can perform dynamic measurement through a microscopic system. In other words, the goal of this research is to develop an optical metrology system that can measure full-field and dynamic nanometer vibrations. By integrating an innovative optical configuration and a newly developed signal algorithm, the above-mentioned goals were completed successfully during the course of this research. In this dissertation, electronic speckle pattern interferometry (ESPI) with high speed CCD camera was adopted to achieve full-filed deformation measurement. By means of short exposure time and precise time control, a series of transient information could be obtained. Image processes including (5,1) phase shifting technology, direct correlation method, noise reduction median filter, and path-independent phase unwrapping method were all integrated to reconstruct surface profile of specimen. Moreover, based on circular polarization interferometer and quadrature signal phase decoded method, laser Doppler interferometry was combined with ESPI system successfully to pursue multi-functional optical metrology system. Besides, an innovative time-stepped phase shifting method has also been proposed. This newly developed process essentially circumvents the de-correlation problem faced by incorporating ESPI technology into microscopic system. The newly developed time-stepped quadrature phase shifting method can even remove the phase shifting device so as to thoroughly improve the accuracy. With regard to the experimental achievements, the optimal optical configuration has been constructed according to the optical simulation results. In addition, the complete experimental process control system and signal/image analysis interface have also been developed. In summary, the vibration measurement results obtained from a piezoelectric plate verifies the performance of the innovative optical metrology system disclosed and accuracy of the newly developed algorithm adopted.
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Liao, Ting, and 廖庭. "A Time of Flight (ToF) CMOS Depth Image Sensor with In-Pixel Background Cancellation and Sensitivity Improvement Using Phase Shifting Readout Technique." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/r3q5ke.
Full textAbstract:
碩士國立清華大學
電機工程學系
105
Range image is one of the popular application in smart image sensor. The increase need for three-dimensional image has been created by consumer electronics applications such as gaming control, robotic vison, gesture recognition and security systems. For above applications, the design of depth camera capable of capturing three-dimensional information in real time with high accuracy under outdoor light illumination becomes very critical. In this thesis, a depth image sensor is proposed to improve the performance of background suppression at strong ambient light environments. The sensitivity is enhanced and hence improves the performance of depth information accuracy. This paper presents a CMOS time-of-flight (TOF) image sensor with in-pixel background light cancellation for outdoor depth imaging application. The usage of P+/N-well diode with proposed polarity switching integration and phase-shift readout (PSR) technique achieves the in-pixel background cancellation capability and sensitivity improvement. Moreover, the PSR also suppresses the column fixed-pattern-noise (FPN) without need of extra frame capturing. A prototype TOF sensing chip with 64×64 pixel array has been fabricated in TSMC standard 0.18μm CMOS process and verified. The pixel pitch is 20μm with a fill-factor of 33%. The achieved depth measurement range is 0.75 to 7.5 meters with a linearity error below 1.1%. The measured relative precision is 4.2% at a 7.5-meter target distance; and the background light suppression capability is up to 180k lux without saturation.
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Matthews, Bjorn. "Demand side management of a run-of-mine ore milling circuit." Diss., 2015. http://hdl.handle.net/2263/44020.
Full textAbstract:
In South Africa, where 75% of the worlds platinum is produced, electricity tariffs have increased significantly over recent years. This introduces challenges to the energy intensive mineral processing industry. Within the mineral processing chain, run-of-mine ore milling circuits are the most energy-intensive unit processes. Opportunities to reduce the operating costs associated with power consumption through process control are explored in this work.
In order to reduce operating costs, demand side management was implemented on a milling circuit using load shifting. Time-of-use tariffs were exploited by shifting power consumption of the milling circuit from more expensive to cheaper tariff periods in order to reduce overall costs associated with electricity consumption. Reduced throughput during high tariff periods was recovered during low tariff periods in order to maintain milling circuit throughput over a week long horizon.
In order to implement and evaluate demand side management through process control, a load shifting controller was developed for the non-linear Hulbert model. Implementation of the load shifting controller was achieved through a multi-layered control approach. A regulatory linear MPC controller was developed to address technical control requirements such as milling circuit stability. A supervisory real-time optimizer was developed to meet economic control requirements such as reducing electricity costs while maintaining throughput.
Scenarios, designed to evaluate the sensitivities of the load shifting controller, showed interesting results. Mill power set-point optimization was found to be proportionally related to the mineral price. Set-points were not sensitive to absolute electricity costs but rather to the relationships between peak, standard, and off-peak electricity costs. The load shifting controller was most effective at controlling the milling circuit where weekly throughput was between approximately 90% and 100% of the maximum throughput capacity.
From an economic point of view, it is shown that for milling circuits that are not throughput constrained, load shifting can reduce operating costs associated with electricity consumption. Simulations performed indicate that realizable cost savings are between R16.51 and R20.78 per gram of unrefined platinum processed by the milling circuit. This amounts to a potential annual cost saving of up to R1.89 m for a milling circuit that processes 90 t/h at a head grade of 3 g/t.Dissertation (MEng)--University of Pretoria, 2015.
Electrical, Electronic and Computer Engineering
Unrestricted
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Ferreira, Celso Joel Oliveira. "Microfluidic methods for the controlled preparation of soft self-assembled nanocarriers for drug delivery." Master's thesis, 2018. http://hdl.handle.net/1822/65059.
Full textAbstract:
Dissertação de mestrado em Biophysics and BionanosystemsCubosomes are dispersions of lipid bicontinuous cubic phases in water. These particles consist of an interior continuous matrix of lipid bilayers arranged in a 3D lattice of cubic symmetry that separates two independent continuous networks of water channels. This coexistence of lipidic and aqueous domains makes cubosomes promising candidates for the encapsulation and delivery of both hydrophobic and hydrophilic drugs. Cubosomes are typically prepared either by fragmenting the cubic liquid crystal in excess water using high energy input (e.g. ultra-sonication), or using solvent-shifting approaches, in which the lipid is first dissolved in a water-miscible solvent (typically ethanol), and later mixed with water and polymer stabilizer. In both cases, poor experimental control at the micron- and nanoscales (e.g. poor control on concentration and heat gradients), limits the fine tuning of the particle properties and results in cubosomes with broad size distributions. In this work, we employ the solvent-shifting method to the monoolein-ethanol-water system and form cubosomes. For this, a microfluidic device capable of mixing the fluids in a rapid and controlled way at the micron-scale, and obtaining cubosomes of tuneable size and low polydispersity, is used. The micron-sized channels in microfluidics lead to laminar flow regimes and enhanced experimental control. In this regime, hydrodynamic focusing can be used to narrow down the length that solvent molecules have to travel to mix, thus decreasing the mixing time. An ethanol-lipid solution is flowed in a central inlet, which is squeezed by two side streams of water with stabilizer. As the lipid-ethanol solution narrows, ethanol and water are mixed in a controlled way by diffusion, leading to formation of cubosomes. By manipulating the flow rate ratio between the two solutions we manipulate the width in which the hydrodynamic focusing occurs, influencing the assembly time in a homogeneous way. This way, by manipulating the flow rate ratio, we were able to tune the size of the cubosome nanoparticles, achieving smaller sizes when increasing the extent of the hydrodynamic focusing (i.e. increasing the flow rate ratio). In addition, the final particle size was also found to be influenced by the composition of the initial solutions. At lipid concentrations above 1 wt% in the ethanolic solution, control over the final particle size is lost. Likewise, inclusion of dioctadecyldimethylammonium bromide (a cationic surfactant) into the formulation also led to large and size-uncontrolled particles. On the other hand, including 29% of water in the initial ethanolic solution leads to smaller particle sizes in the end, also in a controlled way also dependent on the flow rate ratio. In contrast, using a stabilizer to lipid ratio of 1:1 or 3:1 did not show a significant change in the final sizes obtained. Altogether, these results suggest that cubosome size is directly dependent on the exchange rate of solvent molecules until a critical water concentration that induces particle formation is achieved. By allowing a precise control over the mixing and exchange between the two solvents, microfluidics promises to be a promising approach to further tailor the structure and efficiency of drug delivery systems. Nanoparticle size is a key parameter in the carriage of pharmaceuticals. Controlling cubosome size is therefore a relevant step towards the design of new and more efficient formulations.
Cubossomas são dispersões lipídicas de fases cúbicas bicontínuas em água. Estas partículas possuem no seu interior uma matriz de bicamadas lipídicas arranjadas numa rede tridimensional contínua de simetria cúbica que separa duas redes continuas de canais de água. Tal coexistência de domínios lipídicos e aquosos faz dos cubossomas excelentes candidatos para a encapsulação e entrega de compostos hidrofóbicos e hidrofílicos. Os cubossomas são geralmente preparados quer por fragmentação da fase bicontínua cúbica em excesso de água ao introduzir uma grande quantidade de energia (como por exemplo ultra-sonicação), ou então por uma troca de solventes, no qual o lípido é primeiramente dissolvido num solvente miscível em água (tipicamente o etanol), e mais tarde dissolvido em água e um polímero estabilizante. Em ambos os casos, um fraco controlo experimental à micro e nano-escala (e.g. fraco controlo nos gradientes de concentração e temperatura), limita a manipulação das propriedades das partículas e resulta em cubossomas com amplas distribuições de tamanho. Neste trabalho, o método da troca de solventes é aplicado ao sistema monooleína-etanol-água para formar cubossomas. Para este fim, um dispositivo de microfluídica capaz de misturar os solventes rápida e controladamente à microescala, e obter cubossomas com tamanhos manipuláveis e baixa polidispersão, foi usado. Os canais à microescala usados nos dispositivos de microfluídica fazem com que o regime de fluxo seja laminar e reforce o controlo experimental. Neste regime, a focagem hidrodinâmica pode ser usada para diminuir a distância que as moléculas têm de atravessar para se misturarem, o que leva a uma diminuição no tempo de mistura. Uma solução de lípido-etanol é inserida pela entrada central, onde será de seguida espremida por dois fluidos laterais de água com estabilizante. À medida que a solução de lípido-etanol é espremida, o etanol e a água vão sendo misturados de uma forma controlada por difusão, o que leva à formação dos cubossomas. Ao manipular o rácio dos diferentes caudais entre as diferentes soluções, a largura à qual a focagem hidrodinâmica se dá é ajustada, influenciando o tempo de associação entre as moléculas lipídicas de forma homogénea. Desta forma, ao manipular o rácio dos caudais, foi possível manipular o tamanho dos cubossomas, atingindo menores tamanhos quando a extensão da focagem hidrodinâmica foi aumentada (aumentando o rácio dos caudais). Conjuntamente, também foi observado que a composição das soluções iniciais também influência o tamanho final das partículas. A concentrações superiores a 1 %(m/m) de lípido na solução de etanol, o controlo sobre o tamanho das partículas é reduzido. Assim como a inclusão do surfactante catiónico brometo de dioctadecil dimetil amónio (DODAB), que na formulação também gerou partículas de grandes tamanhos de forma descontrolada. Por outro lado, a inclusão de 29 %(m/m) de água na solução de lípido-etanol levou a que se formassem partículas com tamanhos reduzidos, também de uma forma controlada e dependente do rácio entre os caudais dos fluidos. A contrastar, quando utilizado um rácio de estabilizante para lípido de 1:1 ou 3:1, os tamanhos finais obtidos não demonstraram diferenças significativas entre ambos os rácios. Resumindo, estes resultados sugerem que o tamanho dos cubossomas está diretamente dependente do ritmo ao qual as moléculas de solvente vão sendo trocadas até atingirem uma concentração crítica de água que induz a formação das partículas. Ao permitir um controlo preciso sobre a mistura e troca entre ambos os solventes, as técnicas de microfluídica assumem-se como uma forma promissora de manipular a estrutura e aumentar a eficiência dos sistemas de entrega de fármacos. O tamanho das nanopartículas é um fator chave na entrega de fármacos e a possibilidade de controlar o tamanho dos cubossomas é, portanto, um passo na direção do desenvolvimento de novas e mais eficientes formulações.
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Hall, Brooke. "Native title and the tide of history : shifting the sands." Thesis, 2002. http://hdl.handle.net/2429/13649.
Full textAbstract:
This thesis is designed to contribute to the discussion of the issues confronting Australian Courts by evaluating the process of recognition and protection of native title and to delineate how it is being shaped. The High Court of Australia's decision in Mabo v. The State of Queensland [No.2] (1992) C.L.R. 1 and the subsequent Native Title Act 1993 (Cth) in Australia have begun the process of recognition and protection of native title. This thesis looks at the scope of the High Court and some Federal Court of Australia decisions since Mabo [No.2], and examines the relationships at law that underlay a theoretical foundation for those decisions. Two relationships underlay the Courts' reasons: relationships to history, and relationships to land. Australian Courts are articulating a particular conception of these relationships, and the foundation of this thesis is to propose a shift in native title discourse to include indigenous perspectives when determining native title claims.
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Kudrna, David. "Mentální a ontologická simulakra: ne-racionalita a ne-reálno v dílech Philipa K. Dicka." Master's thesis, 2020. http://www.nusl.cz/ntk/nusl-415293.
Full textAbstract:
This thesis offers a model for the underlying architecture of the narrative reality in science-fiction works by Philip K. Dick, arguing that Dick's fictional worlds are grounded in the pervasive metamorphosis - the overarching perception of the shifting - of the narrative fabric operating under the conditions of non-rationality and non-reality. The hyphenated coinages conveniently stand for the paradigms of the reality and mental configurations in PKD subverting the seemingly natural dichotomizing oppositions and hierarchies of the real/unreal and the rational/irrational. Bringing in Gilles Deleuze's ontology of difference, this thesis explains the non-rationality and non-reality of Dick's worlds in Deleuzian terms as, firstly, inducing the perception of fictional reality as realizing the innate potential of being by the perpetual becoming of being in multiplicity and, secondly, engendering - in the vein of Deleuzian simulacra - the impossibility of apprehending and categorizing fictional reality unequivocally. The thesis considers and evaluates the underlying assumptions and claims common to various approaches to the subject of reality in PKD's fictions in order to provide the essential context for the following development of the theoretical basis for non-rationality and non-reality shifting....