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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.
131

From Atoms to the Solar System: Generating Lexical Analogies from Text

Chiu, Pei-Wen Andy January 2006 (has links)
A <em>lexical analogy</em> is two pairs of words (<em>w</em><sub>1</sub>, <em>w</em><sub>2</sub>) and (<em>w</em><sub>3</sub>, <em>w</em><sub>4</sub>) such that the relation between <em>w</em><sub>1</sub> and <em>w</em><sub>2</sub> is identical or similar to the relation between <em>w</em><sub>3</sub> and <em>w</em><sub>4</sub>. For example, (<em>abbreviation</em>, <em>word</em>) forms a lexical analogy with (<em>abstract</em>, <em>report</em>), because in both cases the former is a shortened version of the latter. Lexical analogies are of theoretic interest because they represent a second order similarity measure: <em>relational similarity</em>. Lexical analogies are also of practical importance in many applications, including text-understanding and learning ontological relations. <BR> <BR> This thesis presents a novel system that generates lexical analogies from a corpus of text documents. The system is motivated by a well-established theory of analogy-making, and views lexical analogy generation as a series of three processes: identifying pairs of words that are semantically related, finding clues to characterize their relations, and generating lexical analogies by matching pairs of words with similar relations. The system uses a <em>dependency grammar</em> to characterize semantic relations, and applies machine learning techniques to determine their similarities. Empirical evaluation shows that the system performs remarkably well, generating lexical analogies at a precision of over 90%.
132

Design of Lepelletier Epicyclic Gear Mechanisms for Automobile Transmissions

Tsai, Chin-Chin 07 September 2010 (has links)
An epicyclic gear mechanism for automobile transmissions is a device which is connected from engine to driving wheels, and the main purpose is to maintain the revolution speed of engine to be in a desired working range while accelerating or decelerating the automobile. The epicyclic gear mechanisms for automobile transmissions in production are mostly Ravigneaux-type, Parallel-connected type and Lepelletier epicyclic mechanisms, and the Lepelletier epicyclic gear mechanisms is a device which is connected with a simple epicyclic gear mechanism besides the input end to increase the total number of speed ratios of an automatic transmission. For the incompletion in the relative design methodology, a systematic methodology of designing Lepelletier epicyclic gear mechanisms for automobile transmission is described. At first, fundamental and gear-shifting operations of the Lepelletier-type automatic transmissions is introduced, and the basic principles of lever analogy is explained, the gear ratio¡¦s analysis for Lepelletier epicyclic gear mechanisms is illustrated to establish the design requirements. Secondly, gearing-sequence is devised base on the lever analogy diagrams, and a systematical procedure to arrange desired clutches and brakes into epicyclic gear mechanisms is provided, then the number of the teeth of all gears can be calculated. At last, the six-speed and eight-speed Lepelletier automatic transmissions are designed base on the above design procedure. The results of this work obtain 19 types of automatic transmission which could reach six-speed.
133

Innovative Design of Eight-Speed Parallel-Connected Automatic Transmissions for Automobiles

Kuo, Cheng-Sheng 10 September 2012 (has links)
An epicyclic-type automatic transmission is a device that is connected to the back of an engine and sends the power from the engine to the drive wheels. Its job is to keep the engine within a certain angular velocity. For the development of multi-speed parallel-connected automatic transmission for automobiles, the related configuration design methods are still tedious and prone to human error. Therefore, the purpose of this research is to present an efficient methodology for the systematic design of the parallel-connected automatic transmission for automobiles. First, fundamentals and gear-shifting operations of the parallel-connected automatic transmission are illustrated to establish the design requirements, and the theory of the analysis of speed ratios for epicyclic-type automatic transmission is derived based on the concept of lever analogy. Next, one simple clutching-sequence synthesis methods are proposed and illustrated, based on the lever analogy, and the design theory and the procedure of clutch configuration of epicyclic-type automatic transmission are developed. With the above methods, designs of six-speed and eight-speed parallel-connected automatic transmission. Finally, the complete atlas of six-speed and eight-speed parallel-connected automatic transmission can be systematically synthesized from the data of given speed ratios. This proposed design method can also be applied to the development and design of multi-speed parallel-connected automatic transmissions.
134

Analysis Of Analogy Use On Function Concept In The Ninth Grade Mathematics Textbook And Classrooms

Unver, Emel 01 November 2009 (has links) (PDF)
ABSTRACT ANALYSIS OF ANALOGY USE ON FUNCTION CONCEPT IN THE NINTH GRADE MATHEMATICS TEXTBOOK AND CLASSROOMS &Uuml / nver, Emel M.S., Department of Secondary Science and Mathematics Education Supervisor: Assoc.Prof. Dr Behiye UBUZ December 2009, 64 pages The primary objective of the current study was to examine how analogies are used on function concept in the ninth grade mathematics textbook and classrooms. Using qualitative research procedure comprising textbook analysis and classroom observations, a picture was developed of how analogies used on function concept in ninth grade mathematics textbook and classrooms. One mathematics textbook, the primary source for observed classes was selected and analyzed for the study. Chapter entitled as &ldquo / functions&rdquo / in the selected textbook was closely examined for use of analogies therein. Subtitles of the chapter used in the analysis were identified according to the subtitles taught in observed classes. Moreover, the data were obtained from the observation of two teachers&rsquo / 9th grade mathematics clasess during the 7-week data collection period. Totally, twenty-five lessons were videorecorded. Having determined which comparisons would be counted as analogies, each of the textbook and classroom analogies was classified according to an analogy classification framework including eight criteria, modified from that of Thiele and Treagust&rsquo / s (1994). Analysis of the textbook suggested that all the analogies were enriched and functional, majority of them presented in both verbal and pictorial formats, most of them were advance organizers or post-synthesizers and some of them were embedded activators. However, none of them was explained completely and contained any limitations. On the other side, analysis of classroom analogies revealed that nearly all the analogies were functional, enriched or extended presented verbally as embedded activators, and all of them explained absolutely without any stated limitations.
135

Pricing Inflation Indexed Swaps Using An Extended Hjm Framework With Jump Process

Karahan, Ceren 01 December 2010 (has links) (PDF)
Inflation indexed instruments are designed to help protect investors against the changes in the general level of prices. So, they are frequently preferred by investors and they have become increasingly developing part of the market. In this study, firstly, the HJM model and foreign currency analogy used to price of inflation indexed instruments are investigated. Then, the HJM model is extended with finite number of Poisson process. Finally, under the extended HJM model, a pricing derivation of inflation indexed swaps, which are the most liquid ones among inflation indexed instruments in the market, is given.
136

Prediction of land cover in continental United States using machine learning techniques

Agarwalla, Yashika 08 June 2015 (has links)
Land cover is a reliable source for studying changes in the land use patterns at a large scale. With advent of satellite images and remote sensing technologies, land cover classification has become easier and more reliable. In contrast to the conventional land cover classification methods that make use of land and aerial photography, this research uses small scale Digital Elevation Maps and it’s corresponding land cover image obtained from Google Earth Engine. Two machine learning techniques, Boosted Regression Trees and Image Analogy, have been used for classification of land cover regions in continental United States. The topographical features selected for this study include slope, aspect, elevation and topographical index (TI). We assess the efficiency of machine learning techniques in land cover classification using satellite data to establish the topographic-land cover relation. The thesis establishes the topographic-land cover relation, which is crucial for conservation planning, and habitat or species management. The main contribution of the research is its demonstration of the dominance of various topographical attributes and the ability of the techniques used to predict land cover over large regions and to reproduce land cover maps in high resolution. In comparison to traditional remote sensing methods such as, aerial photography, to develop land cover maps, both the methods presented are inexpensive, faster. The need for this research is in synergy with past studies, which show that large-scale data, processing, along with integration and interpretation make automated and accurate methods of change in land cover mapping highly desirable.
137

Making sense of it all : mapping the current to the past

Dennis, John Lawrence, 1973- 02 December 2010 (has links)
What are the representational differences between situations that do and do not map well onto previous experiences? This research offers some answers to this question by having participants compare two narratives that were either reality or fantasy-based. Fantasy-based narratives, with their deviations from reality, were considered similar to situations that do not map well onto previous experience. The concept of systematicity, where high-order relations constrain low-order relations was used to describe such situations (Bowdle & Gentner, 1997). Compared to a reality-based narrative, extra processing is required to maintain a systematic representation of a fantasy-based narrative. One can reduce the amount of processing needed by grounding that fantasy-based narrative in a reality-based or another fantasy-based narrative. Comparative judgments were used to measure processing differences. In three studies, participants read two narratives and then performed a series of comparative judgments derived from retrospective duration judgment (Block, 1992), event-structure perception (Zacks & Tversky, 2001), and structure-mapping theory (Gentner, 1983) research. For example, one of the comparative judgments adopted from structure-mapping theory was the rating of directional similarity, or the similarity rating of the second-read narrative relative to the first-read narrative. Directional similarity was proposed to increase as the amount of processing associated with maintaining a systematic representation of the first and second-read narrative decreased. For Studies 1A-E, the directional similarity was higher for the RealityFirst condition (reality read first) than the FantasyFirst condition (fantasy read first). These results are interpreted as indicated that the increase in directional similarity for the RealityFirst conditions was due to structure lending from the first-read reality-based narrative and that the decrease in directional similarity for the FantasyFirst conditions was due to representational disruption from the first-read fantasy-based narrative. Results also indicated that comparing two reality-based narratives (Studies 2A-B) was similar to comparing two fantasy-based narratives (Studies 3A-B) for the directional similarity and directional duration judgments, but differed for the listing of commonalities and differences and the segmentation of the narrative event structure. According to the systematicity principle (Gentner, 1989), people prefer mappings between two representations that form coherent and highly interconnected structures. The results from Studies 1A-E demonstrate a clear directional preference for the RealityFirst conditions. The results, therefore, indicate that it was more difficult to utilize the inherent structure of the narratives for the FantasyFirst conditions then the RealityFirst conditions. Comparing the results across the final set of studies, the increase in segmentation and increase in word count for the commonalities and differences were clear indications that participants still had difficulties in utilizing the structure of the narratives when both narratives being compared were fantasy-based (Studies 3A-B). In operationalizing systematicity with fantasy and reality-based narratives, I have been able to extend our understanding of how structure-lending can occur between these two narrative types. The results, therefore, extend our understanding of the structural alignment approach to narrative comparisons. But, since this research also involves the theoretical integration of the structure alignment approach (directional similarity and listing of commonalities and differences) with theories of time estimation (directional duration), event structure representation (segmentation), the basic findings herein should be applicable to comparisons ranging from auditory narrative structures to simple lexical units (e.g., unicorns vs. horses) to visual depicted objects (e.g., aliens vs. humans), even if the current set of studies described in this article involved only the comparison of written narrative structure. / text
138

Ett omöjligt uppdrag? : - Det nationella provets skrivdel i svenska / A mission impossible? : National writing assessment in Sweden

Wikman, Mikael, Cavar, Ivan January 2015 (has links)
Uppsatsens syfte är att redogöra för forskningens syn på det nationella skrivprovet inom ämnet svenska. Utifrån ett psykometriskt perspektiv, med inriktning på konstrukt, bedömning och användning, belyser uppsatsen potentiella problembilder med standardiserade prov inom en svensk, norsk och amerikansk kontext. Provet innehar en normerande ställning inom svensk utbildning, där det agerar rättesnöre över vad som utgör goda och mindre goda elevtexter. Forskningen visar också på den svårighet som existerar gällande provets interbedömarreliabilitet, där olika examinatorer bedömer proven olika. Vidare påverkar provet undervisningen, där dess genrepedagogiska utgångspunkt leder till en tanke om progression, där texttyper hierarkiseras. Lärarna upplever att provet är tidskrävande och att de ofta arbetar förberedande med eleverna. Detta leder till att eleverna undervisas i att hantera provsituationen, snarare än att de undervisas i skrivande, något som är problematiskt utifrån aspekter av reliabilitet. Vidare innebär provets normerande ställning att undervisningen anpassas efter de förmågor som provet avser att mäta, vilket resulterar i att eleverna får ta del av en begränsad läroplan. Undersökningen visar på den diskrepans som tycks existera mellan provets olika syften, där det råder en oklarhet i om provet kan fungera som ett komparativt utvärderingsverktyg samtidigt som det är ett utvecklingsverktyg för att främja elevernas skrivande. Frågan är om det är möjligt att skapa ett skrivprov där dessa syften harmoniserar med varandra?
139

Finite element analysis of the human left ventricle in diastole and systole

Beecham, M. C. January 1997 (has links)
Previously, at Brunel University, two computer programs had been developed to facilitate the analysis of the diastolic material properties of the human left ventricle. These two computer programs consisted of; a finite element program, "XL1", which ran upon a Cray-1S/1000 and a post-processor and pre-processor, "HEART", which ran upon the Multics computer system. The computer program "HEART" produced the finite element model, which was then solved by "XL 1", and it also allowed for plotting the results in graphical form, The patient data was supplied by the Royal Brompton Hospital in the form of digitised cine-angiographic X-ray data plus pressure readings. The first stage was to transfer the two separate computer programs "HEART" and "XL 1" to the Sun Workstation system. The two programs were then combined to form a single package which can be used for the automated analysis of the patient data. An investigation into the effect that the elastic modulus ratio has upon the deformation of the left ventricle during diastole was performed. It was found that the effect is quite small and that using this parameter to match overall shape deformation would be extremely sensitive to the accuracy of the initial data. The main part of this work was the implementation of active cardiac contraction, by means of a thermal stress analogy, into the finite element program. This allows the systolic part of the cardiac cycle to be analysed. The analysis of the factors that affect cardiac contraction, including the material properties and boundary conditions was performed. This model was also used to investigate the effect that conditions such as ischaemia and the formation of scar tissue have upon the systolic left ventricle. The use of the thermal stressing analogy for cardiac contraction was demonstrated to mirror global and local deformation when applied to a realistic ventricular geometry.
140

The restructuring of analogical reasoning in planetary science /

Soare, Richard J. January 2004 (has links)
Despite its ubiquity in planetary science, analogue-based reasoning largely has remained unbounded by guidelines of use. Establishing analogical guidelines and putting them to the test is the main aim of the thesis. Towards this end, I discuss the philosophical foundations of analogical reasoning in planetary geomorphology and posit rules of use that facilitate the evaluation of analogical hypotheses. Subsequently, I present four hypotheses concerning aeolian, fluvial and periglacial processes on Mars. Each of these hypotheses is evaluated in terms of the analogical rules presented. The fourth hypothesis is original to this thesis and suggests that a periglacial landscape comprising pingos and small-scale polygonal ground exists in an impact crater located in northwest Utopia Planitia.

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