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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.
51

Multi-precision Function Interpolator for Multimedia Applications

Cheng, Chien-Kang 25 July 2012 (has links)
A multi-precision function interpolator, which is fitted in with the IEEE-754 single precision floating point standard, is proposed in this paper. It provides logarithms, exponentials, reciprocal and square root reciprocal operations. Each operation is able to dynamically select four different precision modes in demand. The hardware architecture is designed with fully pipeline in order to comply with hardware architectures of general digital signal processors (DSPs) and graphics processors (GPUs). When considering the usefulness of each precision mode, it is designed to minimize the error among various modes as far as possible in the beginning. According to the precision from high to low, function interpolator can provide 23, 18, 13 and 8-bit accuracy respectively in spite of the rounding effect. This function interpolator is designed based on the look-up table method. It can get the approximation value of target function through the calculation of quadratic polynomial. The coefficient of quadratic polynomial is obtained by piecewise minimax approximation. Before implementing the hardware, we use the Maple algebra software to generate the quadratic polynomial coefficients of aforementioned four operations, and estimate whether these coefficients can meet IEEE-754 single precision floating point standard. In addition, we take the exhaustive search to check the results generated by our implementation to make sure that it can meet the requirements for various operations and precision modes. When performing one of the above four operations, only the tables of the operation are used to obtain the quadratic polynomial coefficient. Therefore, we can take the advantage of the tri-state buffer as a switch to reduce dynamic power consumption of tables for the other three operations. In addition, when performing lower precision modes, we can turn off a part of hardwares, which are used to calculate the quadratic polynomial, to save the power consumption more effectively. By providing multi-precision hardware, we hope users or developers, those who use the battery device, can choose a lower precision mode within the permissible error range to extend the battery life.
52

A Low-power High-speed 8-bit Pipelining CLA Design Using Dual Threshold Voltage Domino Logic and Low-cost Digital I/Q Separator for DVB-T

Cheng, Tsai-Wen 10 July 2006 (has links)
This thesis includes two topics. One is a low-power high-speed 8-bit pipelining CLA design using dual threshold voltage (dual- Vth) domino logic. The other is a low-cost digital I/Q separator for DVB-T receivers. A high speed and low power 8-bit CLA using dual- Vth domino logic blocks arranged in a PLA-like style with pipelining is presented. According to parallely precharge and sequentially evaluate in a cascaded set of domino logic blocks, transistors in the precharge part and the evaluation part of dual- Vth domino logic are, respectively, replaced by high Vth transistors to reduce subthreshold leakage current through OFF transistors, and low Vth transistors. Moreover, an nMOS transistor is inserted in the precharge phase of the output inverter such that the two-phase dual- Vth domino logic can be properly applied in a pipeline structure. Consequently, the proposed design keeps the advantage of high speed while attaining the effect of low power dissipation. A low-cost digital I/Q separator is presented in the second part of this thesis. Using digital I/Q separator in place of the traditional analog I/Q separator guarantees the design conquer gain and phase mismatch problems between the I and Q channels. The proposed design can berealized by inverters and shifters such that the goal of low cost can be achieved.
53

Characterization and Correction of Analog-to-Digital Converters

Lundin, Henrik January 2005 (has links)
<p>Denna avhandling behandlar analog-digitalomvandling. I synnerhet behandlas postkorrektion av analog-digitalomvandlare (A/D-omvandlare). A/D-omvandlare är i praktiken behäftade med vissa fel som i sin tur ger upphov till distorsion i omvandlarens utsignal. Om felen har ett systematiskt samband med utsignalen kan de avhjälpas genom att korrigera utsignalen i efterhand. Detta verk behandlar den form av postkorrektion som implementeras med hjälp av en tabell ur vilken korrektionsvärden hämtas.</p><p>Innan en A/D-omvandlare kan korrigeras måste felen i den mätas upp. Detta görs genom att estimera omvandlarens överföringsfunktion. I detta arbete behandlas speciellt problemet att skatta kvantiseringsintervallens mittpunkter. Det antas härvid att en referenssignal finns tillgänglig som grund för skattningen. En skattare som baseras på sorterade data visas vara bättre än den vanligtvis använda skattaren baserad på sampelmedelvärde.</p><p>Nästa huvudbidrag visar hur resultatet efter korrigering av en A/D-omvandlare kan predikteras. Omvandlaren antas här ha en viss differentiell olinjäritet och insignalen antas påverkad av ett slumpmässigt brus. Ett postkorrektionssystem, implementerat med begränsad precision, korrigerar utsignalen från A/D-omvandlaren. Ett utryck härleds som beskriver signal-brusförhållandet efter postkorrektion. Förhållandet visar sig bero på den differentiella olinjäritetens varians, det slumpmässiga brusets varians, omvandlarens upplösning samt precisionen med vilken korrektionstermerna beskrivs.</p><p>Till sist behandlas indexering av korrektionstabeller. Valet av metod för att indexera en korrektionstabell påverkar såväl tabellens storlek som förmågan att beskriva och korrigera dynamiska fel. I avhandlingen behandlas i synnerhet tillståndsmodellbaserade metoder, det vill säga metoder där tabellindex bildas som en funktion utav flera på varandra följande sampel. Allmänt gäller att ju fler sampel som används för att bilda ett tabellindex, desto större blir tabellen, samtidigt som förmågan att beskriva dynamiska fel ökar. En indexeringsmetod som endast använder en delmängd av bitarna i varje sampel föreslås här. Vidare så påvisas hur valet av indexeringsbitar kan göras optimalt, och experimentella utvärderingar åskådliggör att tabellstorleken kan reduceras avsevärt utan att fördenskull minska prestanda mer än marginellt.</p><p>De teorier och resultat som framförs här har utvärderats med experimentella A/D-omvandlardata eller genom datorsimuleringar.</p> / <p>Analog-to-digital conversion and quantization constitute the topic of this thesis. Post-correction of analog-to-digital converters (ADCs) is considered in particular. ADCs usually exhibit non-ideal behavior in practice. These non-idealities spawn distortions in the converters output. Whenever the errors are systematic, it is possible to mitigate them by mapping the output into a corrected value. The work herein is focused on problems associated with post-correction using look-up tables. All results presented are supported by experiments or simulations.</p><p>The first problem considered is characterization of the ADC. This is in fact an estimation problem, where the transfer function of the converter should be determined. This thesis deals with estimation of quantization region midpoints, aided by a reference signal. A novel estimator based on order statistics is proposed, and is shown to have superior performance compared with the sample mean traditionally used.</p><p>The second major area deals with predicting the performance of an ADC after post-correction. A converter with static differential nonlinearities and random input noise is considered. A post-correction is applied, but with limited (fixed-point) resolution in the corrected values. An expression for the signal-to-noise and distortion ratio after post-correction is provided. It is shown that the performance is dependent on the variance of the differential nonlinearity, the variance of the random noise, the resolution of the converter and the precision of the correction values.</p><p>Finally, the problem of addressing, or indexing, the correction look-up table is dealt with. The indexing method determines both the memory requirements of the table and the ability to describe and correct dynamically dependent error effects. The work here is devoted to state-space--type indexing schemes, which determine the index from a number of consecutive samples. There is a tradeoff between table size and dynamics: more samples used for indexing gives a higher dependence on dynamic, but also a larger table. An indexing scheme that uses only a subset of the bits in each sample is proposed. It is shown how the selection of bits can be optimized, and the exemplary results show that a substantial reduction in memory size is possible with only marginal reduction of performance.</p>
54

The effects of multimedia annotations on L2 vocabulary immediate recall and reading comprehension: A comparative study of text-picture and audio-picture annotations under incidental and intentional learning conditions

Chen, Zhaohui 01 June 2006 (has links)
This dissertation investigated the effects of multimedia annotation on L2 vocabulary learning and reading comprehension. The overarching objective of this study was to compare the effects of text-picture annotation and audio-picture annotation on L2 vocabulary immediate recall and reading comprehension. This study also sought to examine the different effects under incidental and intentional learning conditions. The participants were 78 intermediate adult ESL learners from three universities in northwest U.S. The participants read an Internet-based English text. Twenty target words, annotated in either text-picture or audio-picture, were embedded in the reading text. The participants accessed the annotations by clicking on the highlighted target words. Two instruments were used for measuring vocabulary immediate recall: Vocabulary Knowledge Scale and Word Recognition Test. Two measurements were used to assess reading comprehension: Multiple-choice Reading Comprehension Questions and L1 Written Recall. In term of annotation types, the results indicated that the audio-picture annotation group did significantly better than the text-picture group in L2 vocabulary immediate recall. However, there was no significantly different effect between the two annotations on L2 reading comprehension. In terms of learning conditions, the intentional learning condition resulted in significantly better performance in L2 vocabulary immediate recall than the incidental learning condition. However, the incidental learning condition resulted in significantly better L2 reading comprehension than the intentional learning condition only in the Written Recall measure, but not in the multiple-choice Reading Comprehension Test. In terms of interaction between annotation type and learning condition, there was not interaction between annotation type and learning condition on L2 vocabulary immediate recall. The interaction between annotation type and learning condition on L2 reading comprehension was not significant in multiple-choice Reading Comprehension Text. However, the interaction was found to be significant in Written Recall: in the incidental learning condition, the difference between text-picture annotation and audio-picture annotation was not significant; in the intentional learning condition, participants in text-picture did significantly better than those in audio-picture on Written Recall.
55

Utilizing Look-Ahead Information to Minimize Fuel Consumption and NOx Emissions in Heavy Duty Vehicles

Florell, Christoffer January 2015 (has links)
Producing more fuel efficient vehicles as well as lowering emissions are of high importance among heavy duty vehicle manufactures. One functionality of lowering fuel consumption is to use a so called \emph{look-ahead control strategy}, which uses the GPS and topography data to determine the optimal velocity profile in the future. When driving downhill in slopes, no fuel is supplied to the engine which lowers the temperature in the aftertreatment system. This results in a reduced emission reduction capability of the aftertreatment system. This master thesis investigates the possibilities of using preheating look-ahead control actions to heat the aftertreatment system before entering a downhill slope, with the purpose of lowering fuel consumption and $NO_x$ emissions. A temperature model of a heavy duty aftertreatment system is produced, which is used to analyse the fuel consumption and $NO_x$ reduction performance of a Scania truck. A Dynamic Programming algorithm is also developed with the purpose of defining an optimal control trajectory for minimizing the fuel consumption and released $NO_x$ emissions. It is concluded that the Dynamic Programming optimization initiates preheating control actions with results of fuel consumption reduction as well as $NO_x$ emissions reductions. The best case for reducing the maximum amount of fuel consumption results in 0.14\% lower fuel consumption and 5.2\% lower $NO_x$ emissions.
56

Laisvalaikiu sportuojančių vyrų ir moterų savo išvaizdos vertinimas ir su juo susijusių veiksnių analizė / Self look evaluation of men and women going in for sports at their leisure time and analysis of the related factors

Radišauskaitė, Vaida 16 August 2007 (has links)
Privatus sektorius sporte Lietuvoje plečiasi: 2001 metais sporto klubų buvo apie 45 , o 2005 metais išaugo iki 100. Pastaruoju metu visuomenėje formuojamas požiūris, kad sporto klubo lankymas yra gyvenimo būtinybė, prestižo reikalas. Vieni svarbiausių sportavimo motyvų yra jaunatviškai ir patraukliai atrodyti, todėl sveikatingumo rinka Lietuvoje plečiasi. Augant sporto klubų skaičiui, daugėja ir laisvalaikiu sportuojančių žmonių skaičius. Privačių sporte klubų lankytojai dažnai yra turtingesni negu vidutines pajamas gaunantys, todėl jų reikalavimai išvaizdai yra taip pat aukštesni. Ypač savo išvaizdai reiklios laisvalaikiu sportuojančios moterys. Dažnai tenka stebėti, kad jos perdėtai domisi svorio kontrole, naudoja įvairias farmakologines priemones kūno svoriui mažinti ir dažnai būna neobjektyviai įsitikinusios, kad jų svoris yra per didelis. Toks įsitikinimas veda prie neracionalių svorio kontrolės būdų, kaip badavimas, įvairių moksliniais tyrimais nepagrįstų dietų laikymasis, besaikis mankštinimasis, depresija ar net valgymo sutrikimai. Žinoma, kad sportavimas gali padėti gerinti žmonių savo kūno vertinimą, tačiau Lietuvoje tokių tyrimų atlikta mažai. Nėra žinoma, kiek žmonių yra nepatenkinti savo kūno išvaizda ir kaip su tuo susijęs sportavimas. Tuo remiantis, planuoju tyrime kelti tokį probleminį klausimą: ar laisvalaikiu sportuojantys vyrai ir moterys savo kūno išvaizdą vertina tik teigiamai? Probleminio klausimo suformulavimas įgalino iškelti šią tyrimo prielaidą... [toliau žr. visą tekstą] / Private sector of sport in Lithuania is expanding: in 2001 there were only 45 sport clubs and in 2005 this number has reached 100. At the moment in society is forming attitude that going to sport club is essential and part of status symbol. In association with growing number of sport clubs there are more people involving in sporting at leisure time. People attending private sport clubs usually are richer than those who get average incomes. There is also noticeable that these people give more attention to his/her appearance. Especially big attention to appearance gives women who are actively taking sports. Usually these women are wrongly evaluating their own weight (as they see themselves to heavy) and using various pharmacological conditioning to lose weight. This attitude leads these women to irrational ways of losing weight, as example: starvation, being on various unknown diets, inordinate exercising, depression and even derangement of eating habits. It is known that sporting can help to improve peoples own body evaluating; however there aren’t done enough that kind researches. It is not known how many people are dissatisfied of his/her own appearance and how with all this is related sporting. So in my research has been held this problematical question: are men and women who is taking sport at their leisure time evaluating their own appearance only positively? In consideration with problematic question there was brought hypothesis of research: men and women who is... [to full text]
57

A CONTROL MECHANISM TO THE ANYWHERE PIXEL ROUTER

Krishnan, Subhasri 01 January 2007 (has links)
Traditionally large format displays have been achieved using software. A new technique of using hardware based anywhere pixel routing is explored in this thesis. Information stored in a Look Up Table (LUT) in the hardware can be used to tile two image streams to produce a seamless image display. This thesis develops a 1 input-image 1 output-image system that implements arbitrary image warping on the image, based a LUT stored in memory. The developed system control mechanism is first validated using simulation results. It is next validated via implementation to a Field Programmable Gate Array (FPGA) based hardware prototype and appropriate experimental testing. It was validated by changing the contents of the LUT and observing that the resulting changes on the pixel mapping were always correct.
58

The buried life seen through walls of stone in <i>Look homeward, angel</i> by Thomas Wolfe

Fiordelli, Cristina January 2006 (has links)
No se posee.
59

Fuel Consumption Estimation for Vehicle Configuration Optimization / Bränsleförbrukningssimuleringar för optimering av fordonsspecifikationer

Söderstedt, Fredrik January 2014 (has links)
Fuel consumption is one of the factors that are considered when deciding a vehicle’s optimal specification. In order to swiftly estimate the fuel consumed during real world driving scenarios, a simulation tool has been developed that is well suited for vehicle configuration exploration applications. The simulation method described in this paper differs from the static calculation method currently in use at Scania cv since the dynamic translation of the vehicle is considered, yet the simulation time is kept low. By adopting a more dynamic approach, the estimation accuracy is increased and simulation of fuel saving technology, e.g. intelli- gent driver support system, is enabled. In this paper, the modeling and implementation process is described. Different approaches is discussed and the choices made during the development is presented. In order to achieve a low simulation time and obtain a good compatability with Scania’s current software application, some of the influencial factors have been omitted from the model or described using simple relations. The validation of the fuel consumption estimation indicates an accuracy within three percent for motorway driving. Utilizing the newly devised simulation tool, a look-ahead cruise controller has been implemented and simulated. Instead of continuously finding the optimal control signals during the driving scenario like most look-aheadcontrollers, a dynamic programming algorithm is used to find a fuel efficient speed profile for the entire route. The speed profile is used as the reference speed for a conventional cruise controller and comparison with another simulation tool indicates that this is a fast and accurate way to emulate a real look-ahead controller.
60

Wo ist das Gefühl?

Freitag, Georg, Wacker , Markus 27 May 2014 (has links) (PDF)
"Das Programm sieht ja nicht nur gut aus, es macht auch genau das was ich will!" - solche oder ähnliche Aussagen liest man oft, wenn Software-Programme von Anwendern beurteilt werden. Was Nutzer damit beschreiben ist weitestgehend als Look & Feel einer Anwendung bekannt. Der Begriff Look bezieht sich dabei auf die visuellen Bestandteile der Anwendung, wie die genutzten Medienelemente und deren Layout. Das Themenfeld Feel umfasst das interaktive Verhalten einer Anwendung, die auf Eingaben des Nutzers reagiert (Feedback) oder bereits vorher Hinweise auf die eigene Verwendbarkeit gibt (Feed-Forward). Allgemein gilt, je interaktiver eine Anwendung, desto wichtiger ist das "Gefühl" im Look & Feel. Als Beispiel dienen die sogenannten natürlichen Benutzerschnittstellen (NUI), wie die sich in den letzten Jahren enorm verbreitende Form des Multi-Touches. Bei dieser interagiert der Nutzer direkt mit der Anwendung ohne separate Eingabegeräte als Vermittler seiner Aktionen. Eine weitere Charakteristik dieser Benutzerschnittstellen ist deren intuitive Verwendbarkeit. Dies bedeutet, dass sich während der Interaktion mit den Programmen deren Strukturen und Funktionen von selbst erschließen. Um dies zu gewährleisten ist die sorgsame Gestaltung des Feels von Beginn der Entwicklung an bedeutsam. Umso überraschender ist das Ergebnis unseres Vergleichs aktueller Prototyping-Werkzeuge für Benutzeroberflächen, die den Aspekt Feel oftmals nicht oder nur unzureichend berücksichtigen und stattdessen das Aussehen (Look) einer Anwendung fokussieren. In unserer kürzlich erschienenen Arbeit "Look without Feel - A Basal Gap in the Multi-Touch Prototyping Process", die wir auf der Konferenz "Mensch und Computer 2013" in Bremen präsentierten und die mit dem Honorable Mention Paper Award ausgezeichnet wurde, untersuchten wir diesen Sachverhalt für den Prototyping-Prozess von Multi-Touch Anwendungen genauer.

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