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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Unsteady Flow Sensing and Estimation via the Gappy Proper Orthogonal Decomposition

Willcox, Karen E. 01 1900 (has links)
The proper orthogonal decomposition (POD) has been widely used in fluid dynamic applications for extracting dominant flow features. The “gappy” POD is an extension to this method that allows the consideration of incomplete data sets. In this paper, the gappy POD is extended to handle unsteady flow reconstruction problems, such as those encountered when limited flow measurement data is available. In addition, a systematic approach for effective sensor placement is formulated within the gappy framework. Two applications are considered. The first aims to reconstruct the unsteady flow field using a small number of surface pressure measurements for a subsonic airfoil undergoing plunging motion. The second considers estimation of POD modal content of a cylinder wake flow for active control purposes. In both cases, using the dominant POD basis vectors and a small number of sensor signals, the gappy approach is found to yield accurate flow reconstruction results. / Singapore-MIT Alliance (SMA)
22

Model Order Reduction for Determining Bubble Parameters to Attain a Desired Fluid Surface Shape

My-Ha, D., Lim, K. M., Khoo, Boo Cheong, Willcox, Karen E. 01 1900 (has links)
In this paper, a new methodology for predicting fluid free surface shape using Model Order Reduction (MOR) is presented. Proper Orthogonal Decomposition combined with a linear interpolation procedure for its coefficient is applied to a problem involving bubble dynamics near to a free surface. A model is developed to accurately and efficiently capture the variation of the free surface shape with different bubble parameters. In addition, a systematic approach is developed within the MOR framework to find the best initial locations and pressures for a set of bubbles beneath the quiescent free surface such that the resultant free surface attained is close to a desired shape. Predictions of the free surface in two-dimensions and three-dimensions are presented. / Singapore-MIT Alliance (SMA)
23

Health and Place : Terminology, proper nouns and titles of cited publications in the translation of a text on medical geology

Håkansson, Susanne January 2010 (has links)
This essay deals with some of the difficulties that translation of a technical text may present, more specifically the handling of terminology, proper nouns and titles of cited publications. For this purpose, a text dealing with medical geology, taken from Essentials of Medical Geology (Selinus et al., 2005), was translated and analysed. Medical geology is an interdisciplinary science and hence contains terminology from several different scientific areas. The present study includes terminology within the field of medicine and geochemistry in the analysis. The preferred and predominant translation procedure was literal translation (Munday, 2001:57). Many source text terms have synonyms in the target language. With the intention to preserve and transfer the level of technical style into the target text, terms were analysed and classified as belonging to one of three levels of technical style: academic, professional and popular (Newmark, 1988:151). The handling of proper nouns connected to medicine and geology was also included in the analysis. One common procedure is to use a translation which is established in the target language. The present study discusses the strategies used when no such established translation was found. The procedure of using a recognised translation was discussed in connection to the handling of titles of cited publications referred to in the source text.
24

Lost in Translation : A study on the two English translations of The Brothers Lionheart

Walles, Johan January 2008 (has links)
This study investigates the translation of cultural features in fiction. It is based on two translations into English of the Swedish book The Brothers Lionheart and its focus lies on proper names, place names, food, and dialect. Acomparison between the two translations is also made. The results showed that there were differences in the translation of proper names, place names, and food. While the overall differences for proper names, place names and food were small, there were big differences in the way some proper names and food were translated. However, these cases were very few, and on the whole, the translations resemble each other in most areas. As regards the translation of dialect, this was completely omitted in both translations.
25

A reduced-order model based on proper orthogonal decomposition for non-isothermal two-phase flows

Richardson, Brian Ross 15 May 2009 (has links)
This thesis presents a study of reduced-order models based on proper orthogonal decomposition applied to non-isothermal transport phenomena in °uidized beds. A numerical °ow solver called Multiphase Flow with Interphase eXchanges (MFIX) was used to generate a database of solution snapshots for proper orthogonal decomposi- tion (POD). Using POD, time independent basis functions were extracted from the data and the governing equations of the numerical solver were projected onto the basis functions to generate reduced-order models. A reduced-order model was constructed that simulates multi-phase isothermal and non-isothermal °ow. In the reduced-order models (ROMs) the large number of partial di®erential equations were replaced by a much smaller number of ordinary di®erential equations. These reduced-order models were applied to two reference cases, a time extrapolation case and a time-dependent period boundary condition case. Three additional acceleration techniques were devel- oped to further improve computational e±ciency of the POD based ROM: 1) Database splitting, 2) Freezing the matrix of the linear system and 3) Time step adjustment. Detailed numerical analysis of both the full-order model, MFIX and the POD-based ROM, including estimating the number of operations and the CPU time per iteration, was performed as part of this study. The results of this investigation show that the reduced-order models are capable of producing qualitatively accurate results with less than 5% error with a two-order of magnitude reduction of computational costs.
26

Advances in Reduced-Order Modeling Based on Proper Orthogonal Decomposition for Single and Two-Phase Flows

Fontenot, Raymond Lee 2010 December 1900 (has links)
This thesis presents advances in reduced-order modeling based on proper orthogonal decomposition (POD) for single and two-phase flows. Reduced-order models (ROMs) are generated for two-phase gas-solid flows. A multiphase numerical flow solver, MFIX, is used to generate a database of solution snapshots for proper orthogonal decomposition. Time-independent basis functions are extracted using POD from the data, and the governing equations of the MFIX are projected onto the basis functions to generate the multiphase POD-based ROMs. Reduced-order models are constructed to simulate multiphase two-dimensional non-isothermal flow and isothermal flow particle kinetics and three-dimensional isothermal flow. These reduced-order models are applied to three reference cases. The results of this investigation show that the two-dimensional reduced-order models are capable of producing qualitatively accurate results with less than 5 percent error with at least an order of magnitude reduction of computational costs. The three-dimensional ROM shows improvements in computational costs. This thesis also presents an algorithm based on mathematical morphology used to extract discontinuities present in quasi-steady and unsteady flows for POD basis augmentation. Both MFIX and a Reynolds Average Navier-Stokes (RANS) flow solver, UNS3D, are used to generate solution databases for feature extraction. The algorithm is applied to bubbling uidized beds, transonic airfoils, and turbomachinery seals. The results of this investigation show that all of the important features are extracted without loss in accuracy.
27

Reduced order modeling for transport phenomena based on proper orthogonal decomposition

Yuan, Tao 17 February 2005 (has links)
In this thesis, a reduced order model (ROM) based on the proper orthogonal decomposition (POD) for the transport phenomena in fluidized beds has been developed. The reduced order model is tested first on a gas-only flow. Two different strategies and implementations are described for this case. Next, a ROM for a two-dimensional gas-solids fluidized bed is presented. A ROM is developed for a range of diameters of the solids particles. The reconstructed solution is calculated and compared against the full order solution. The differences between the ROM and the full order solution are smaller than 3.2% if the diameters of the solids particles are in the range of diameters used for POD database generation. Otherwise, the errors increase up to 10% for the cases presented herein. The computational time of the ROM varied between 25% and 33% of the computational time of the full order solution. The computational speed-up depended on the complexity of the transport phenomena, ROM methodology and reconstruction error. In this thesis, we also investigated the accuracy of the reduced order model based on the POD. When analyzing the accuracy, we used two simple sets of governing partial differential equations: a non-homogeneous Burgers' equation and a system of two coupled Burgers' equations.
28

Baltų vardyno tyrimo principai Huberto Gurnovičiaus tekstuose / Principles of Baltic proper names index studies in texts of Hubert Górnowicz

Rogoža, Irena 24 September 2008 (has links)
Baltų vardyno tyrimo principai Huberto Gurnovičiaus tekstuose Summary Hubert Górnowicz – profesorius, onomastinės mokyklos Gdanske įkūrėjas. Jo susidomėjimų ir darbo sritis plati. Tai ir dialektologija, ir toponimija, ir antroponimija. Kalbininko nuopelnai mokslui nemaži. Jis daug nusipelnė baltų vardyno tyrimui, ypač prūsų vardyno tyrimui. Darbo objektas – H. Gurnovičiaus mokslinė veikla. Šio magistro darbo tikslas – aptarti Gurnovičiaus mokslinę veiklą; pateikti principus bei metodus, kuriais jis vadovavosi; nurodyti jo tyrimų, metodų skirtumus nuo kitų kalbininkų; išanalizuoti jo veikalus bei straipsnius (išrinkti iš Gurnovičiaus veikalų prūsų tikrinius vardus, surasti jų darybos pagrindą, identifikuoti šaknines morfemas, susiejant jas su baltų kalbų (prūsų, lietuvių, latvių ir kai kuriais atvejais su lenkų) apeliatyvais, antroponimais, nustatyti darybines morfemas); panagrinėti, kaip Gurnovičius atstato autentiškas prūsiškų vardų lytis, palyginti jo interpretaciją su kitų prūsų vardyno tyrėjų interpretacijomis. Darbe vartojamos sąvokos bei terminai. Lietuvių kalbotyroje onomastikos specialistų vartojami tiek tarptautiniai terminai, tiek lietuviški jų atitikmenys. Dažniausiai darbe vartojamas terminas yra toponimas arba vietovardis. Juo įvardijamas bet kurios gamtinės ar dirbtinės žemės paviršiaus vietos ar kitokio geografinio objekto tikrinis vardas. Vietovardžių rūšys yra įvairūs gyvenamųjų ir negyvenamųjų vietų vardai, pavyzdžiui, šalių, miestų, kaimų, kalnų, lygumų... [toliau žr. visą tekstą] / Hubert Górnowicz is the founder of the onomastic school in Gdansk. The field of his interests and work is wide. This is dialectology, toponymy as well as anthroponymy. He deserves a lot for his studies of the Baltic proper names index and especially for the Prussian proper names index. The subject of the thesis is the scientific activity of H. Górnowicz. The aim of this Master thesis is to discuss the scientific activity of Górnowicz; to present the principles and methods which he observed by studying the Baltic proper names index, to specify the differences of his research and methods by comparing them to other linguists; to analyze his treatises and articles (to pick out the Prussian proper names from the treatises of Górnowicz, to find the basis of their formation, to identify the root morphemes by relating them to the appellatives, anthroponyms of Eastern Baltic languages (Lithuanian, Latvian and in some cases Polish), to define word-building morphemes; to analyze how Górnowicz restores the authentic genders of Prussian names, to compare his interpretation with the interpretations of other Prussian proper names index researchers. Notions and terms used in the thesis. The specialists of onomastics use both international terms and their Lithuanian equivalents in Lithuanian linguistics. The term used most often in the thesis is a toponym or place-name. The proper name of any natural or artificial earth surface place or another geographical feature is defined by it. The types... [to full text]
29

Video letters, mediation and (proper) distance : A qualitative study of international development communication in practice

Enghel, Florencia January 2014 (has links)
This study scrutinizes the trajectory of an international development communication intervention aimed at mediating, rendering public and mobilizing processes of reconnection among estranged citizens across the former Yugoslavia. The intervention, which took place between 2000 and 2005 in the wider context of post-conflict international development assistance and peacebuilding operations in the region, was known as the Videoletters project. Centered on a documentary TV series aimed at promoting the reestablishment of relationships among ordinary people affected by ethno-political divisions, Videoletters was adopted by European bilateral funders for large-scale implementation and categorized as a “tool for reconciliation”. Starting from an understanding of communication as a right to which citizens are entitled, as a responsibility of practitioners and institutions, and as a capability that is socially distributed in unequal ways and has an ambiguous potential, the study looks into the contextualized potential and limitations of international development communication intervention to attend to the citizens that it is supposed to benefit. By providing rich empirical details about a process of intervention, the study argues in concrete terms for the study of development communication not as a presumably positive tool, but as an institutionally driven practice that may or may not strengthen conditions of justice, with consequences that will differ depending on the specificity of sociopolitical situations in time and space. Depending on contextual and institutional conditions and on the forms of mediation privileged/disregarded throughout the process, the deployment of a specific development communication intervention may/may not foster proper distance, and thus strengthen/weaken conditions of justice for the citizens under consideration, who are subject to the governance structure of international development assistance. By linking the practice of international development communication to a framework of justice, the study brings the political and ethical dimensions of said practice to the fore and contributes to a critical agenda for theorization and research that takes accountability into consideration and puts citizens at the center.
30

”Äter jag inte stark mat är jag inte riktigt människa” : en pilotstudie om mat- och måltidskultur i förhållande till ”proper meals” för fem singalesiska kvinnor boende i Sverige / ”I am not really human if I don´t eat spicy food” : A pilot study on food and food culture in comparison to proper meals for five Sri Lankan women living in Sweden

Calloway, Sherine January 2014 (has links)
En typiskt singalesisk måltid tar lång tid att göra, den ska bestå av flera smårätter och gärna med kryddor från hemlandet. Har den kulturella måltidssynen hos de singalesiska kvinnorna förändrats, förstärkts eller påverkats av att vara i ett annat land och i så fall varför? Är det fortfarande den singalesiska husmanskosten som anses vara ett ”proper meal”? Syftet är att undersöka fem singalesiska kvinnors egna uppfattningar om ämnet ”proper meal” från ett singalesiskt perspektiv och undersöka om deras uppfattning har förändrats under tiden de bott i Sverige. Studien är kvalitativ och för att undersöka hur singalesiska kvinnor uppfattade och tänkte kring dessa frågor har en pilotfokusgrupp samt en skarp fokusgrupp skulle utgjort metoden för datainsamling.  En lunch eller middag ska enligt denna studie vara singalesisk och därigenom bestå av en kött- eller fiskrätt, serveras med ris och två till tre grönsaker som tillbehör för att den ska vara en riktig måltid både till vardagar och helger. Kopplingen till ”proper meals” kan göras från ett singalesiskt perspektiv för vardags-, helg- och även festmåltider. Det framstod också hur matlagningen var förknippad med identiteten och den kulturella tillhörigheten.

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