• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 70
  • 20
  • 3
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 106
  • 106
  • 67
  • 64
  • 38
  • 32
  • 28
  • 25
  • 20
  • 16
  • 15
  • 14
  • 13
  • 13
  • 13
  • 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.
101

Efficient Query Processing for Dynamically Changing Datasets

Idris, Muhammad, Ugarte, Martín, Vansummeren, Stijn, Voigt, Hannes, Lehner, Wolfgang 11 August 2022 (has links)
The ability to efficiently analyze changing data is a key requirement of many real-time analytics applications. Traditional approaches to this problem were developed around the notion of Incremental View Maintenance (IVM), and are based either on the materialization of subresults (to avoid their recomputation) or on the recomputation of subresults (to avoid the space overhead of materialization). Both techniques are suboptimal: instead of materializing results and subresults, one may also maintain a data structure that supports efficient maintenance under updates and from which the full query result can quickly be enumerated. In two previous articles, we have presented algorithms for dynamically evaluating queries that are easy to implement, efficient, and can be naturally extended to evaluate queries from a wide range of application domains. In this paper, we discuss our algorithm and its complexity, explaining the main components behind its efficiency. Finally, we show experiments that compare our algorithm to a state-of-the-art (Higher-order) IVM engine, as well as to a prominent complex event recognition engine. Our approach outperforms the competitor systems by up to two orders of magnitude in processing time, and one order in memory consumption.
102

A concepção de avaliação educacional veiculada na produção acadêmica do Programa de Pós-Graduação em Educação: Currículo (1975-2000) / The conception of educational assessment diffused in the academic production of the Education Post-Graduate Program: Syllabus (1975-2000)

Teixeira, Célia Regina 17 October 2006 (has links)
Made available in DSpace on 2016-04-27T14:31:54Z (GMT). No. of bitstreams: 1 CED - Celia Regina Teixeira.pdf: 565928 bytes, checksum: 110e6078962853736c75e6340ee95470 (MD5) Previous issue date: 2006-10-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this study is to document, organize and understand the conception of EDUCATIONAL ASSESSMENT diffused in the academic production of the Education Post-Graduate Program: São Paulo Pontifícia Universidade Católica Syllabus between 1975 and 2000. Of the State of the Art and State of Knowledge study in the academic production, composed of doctoral theses and master s dissertations on educational assessment (1975-2000), 22 works were selected covering the conceptions of educational assessment produced in the Education Post-Graduate Program: Syllabus in the above mentioned period. The research was contextualized by outlining the setting composed of the post-graduate program and the conceptions of thesis and dissertation professor-tutors, based on a qualitative approach. Thesis and dissertation abstracts were analyzed and organized by using the following descriptors: theme, scope, highlighted aspects and contributions to the educational assessment conception. The research indicates that the Education Post-Graduate Program: Syllabus presents a significant set of production in the area of educational assessment, and it has become a national reference. It was possible to observe a movement in the educational assessment conceptions, which, having started with a measuring view, move towards an emancipatory view, which represents a pioneering mark in Brazilian assessment studies / Este estudo tem como objetivo documentar, organizar e compreender a concepção de AVALIAÇÃO EDUCACIONAL veiculada na produção acadêmica do Programa de Pós-Graduação em Educação: Currículo da Pontifícia Universidade Católica de São Paulo, no período de 1975 a 2000. A partir do estudo do Estado da Arte ou Estado do Conhecimento da produção acadêmica, constituída de teses de doutoramento e dissertações de mestrado sobre avaliação educacional (1975- 2000) foram selecionados 22 trabalhos em que estão contempladas concepções sobre avaliação educacional produzidos no Programa de Pós-Graduação em Educação: Currículo no período mencionado. A pesquisa foi contextualizada a partir do delineamento do cenário constituído pelo programa de pós-graduação e pelas concepções dos docentes-orientadores das teses e dissertações , segundo uma abordagem qualitativa. Os resumos das teses e dissertações foram analisados e organizados adotando-se como descritores: tema, abrangência, aspectos em destaque e contribuições para a concepção de avaliação educacional. A pesquisa aponta o fato de que o Programa de Pós-Graduação em Educação: Currículo apresenta um significativo conjunto de produções na área de avaliação educacional, tendo-se tornado uma referê ncia nacional. Constata -se uma trajetória das concepções de avaliação educacional que , partindo de uma visão de mensuração, encaminha-se para uma proposta emancipatória, constituindo um marco pioneiro dos estudos avaliativos brasileiros
103

Panorama das dissertações de educação matemática sobre o ensino superior da PUC/SP de 1994 a 2000

Junho, Benedito Afonso Pinto 13 November 2003 (has links)
Made available in DSpace on 2016-04-27T16:58:07Z (GMT). No. of bitstreams: 1 dissertacao_benedito_junho.pdf: 448337 bytes, checksum: 6cad7afc1b66e6f62e4db6ba05f6f36d (MD5) Previous issue date: 2003-11-13 / The aim of this work was to construct a map of the dissertations related to Higher Education produced in the Program of Post-Graduate Studies in Mathematics Education of the Pontifícia Catholic University of São Paulo throughout the 90s decade. Following the analysis of each of the ten dissertations studied, it was possible to categorize them according to the themes investigated and the methodologies used. The results obtained indicated that the majority of the studies concerned the teaching and learning of disciplines associated with pure mathematics and employed as a research strategy the elaboration and application of a didactic sequence based on the methodology of Didactic Engineering / Este trabalho teve como objetivo, fazer um mapeamento das dissertações produzidas no Programa de Estudos Pós-graduados em Educação Matemática da Pontifícia Universidade Católica de São Paulo, na década de noventa, que versavam sobre o Ensino Superior. Após análise de cada uma das dez obras, foi possível categorizá-las principalmente quanto aos temas abordados e metodologias utilizadas. Os resultados obtidos permitiram concluir que a maioria das pesquisas abordou o ensino e aprendizagem de disciplinas de matemática pura , e elegeu como estratégia de pesquisa, a elaboração e aplicação de uma seqüência didática, baseada na metodologia da Engenharia Didática
104

A Educação matemática & ensino fundamental: um panorama das pesquisas produzidas na PUC/SP nos anos 1994 a 1997

Perreira, Luciane Maciel Xavier de Oliveira 06 October 2003 (has links)
Made available in DSpace on 2016-04-27T16:58:12Z (GMT). No. of bitstreams: 1 dissertacao_luciane_maciel_xavier_pereira.pdf: 466559 bytes, checksum: 9b6c922071168b01d504e5df9226b8fd (MD5) Previous issue date: 2003-10-06 / The present work aimed to analyze the dissertations about The Teaching in Elementary School, produced in the Program of Post-Graduate Studies of Mathematics Education at a Catholic University Pontifícia Universidade Católica de São Paulo, in the period from 1994 to 1997. After the analysis of the eight dissertations, it was possible to categorize them in relation to the chosen objective of the research. The attained results allowed to conclude that the preferences in the research were the contents worked in the classroom and they were divided into the teacher and student s point of view, and fifty percent of these papers (dissertations) have chosen as theme the numbers and their operations. Beside this, most of the papers (seven) have tried to create a situation in where they could develop a significance to the chosen Mathematics notions / Este trabalho teve como objetivo, fazer um mapeamento das dissertações sobre assunto do Ensino Fundamental, produzidas no Programa de Estudos Pós-Graduação em Educação Matemática da Pontifícia Universidade Católica de São Paulo, no período de 1994 a 1997 inclusive. Após a análise de cada uma das oito obras, foi possível categorizá-las principalmente quanto ao objetivo de pesquisa escolhido. Os resultados obtidos permitiram concluir que a preferência das pesquisas foi por conteúdos trabalhados em sala de aula, distribuídos em dois pontos de vista do professor ou do aluno, sendo que a metade dos autores desses trabalhos escolheu como tema números e suas operações Além disso, a maioria (sete dissertações) mostrou uma preocupação em criar situações que propiciassem o desenvolvimento de significado para as noções matemáticas escolhidas
105

Analysis and design of efficient passive components for the millimeter-wave and THz bands

Berenguer Verdú, Antonio José 29 June 2017 (has links)
This thesis tackles issues of particular interest regarding analysis and design of passive components at the mm-wave and Terahertz (THz) bands. Innovative analysis techniques and modeling of complex structures, design procedures, and practical implementation of advanced passive devices are presented. The first part of the thesis is dedicated to THz passive components. These days, THz technology suffers from the lack of suitable waveguiding structures since both, metals and dielectric, are lossy at THz frequencies. This implies that neither conventional closed metallic structures used at microwave frequencies, nor dielectric waveguides used in the optical regime, are adequate solutions. Among a variety of new proposals, the Single Wire Waveguide (SWW) stands out due to its low attenuation and dispersion. However, this surface waveguide presents difficult excitation and strong radiation on bends. A Dielectric-Coated Single Wire Waveguide (DCSWW) can be used to alleviate these problems, but advantages of the SWW are lost and new problems arise. Until now, literature has not given proper solution to radiation on bends and, on the other hand, rigorous characterization of these waveguides lacks these days. This thesis provides, for the first time, a complete modal analysis of both waveguides, appropriated for THz frequencies. This analysis is later applied to solve the problem of radiation on bends. Several structures and design procedures to alleviate radiation losses are presented and experimentally validated. The second part of the thesis is dedicated to mm-wave passive components. These days, when implementing passive components to operate at such small, millimetric wavelengths, to ensure proper metallic contact and alignment between parts results challenging. In addition, dielectric absorption becomes significant at mm-wave frequencies. Consequently, conventional hollow metallic waveguides and planar transmission lines present high attenuation so that new topologies are being considered. Gap Waveguides (GWs), based on a periodic structure introducing an Electromagnetic Bandgap effect, result very suitable since they do not require metallic contacts and avoid dielectric losses. However, although GWs have great potential, several issues prevent GW technology from becoming consolidated and universally used. On the one hand, the topological complexity of GWs difficulties the design process since full-wave simulations are time-costly and there is a lack of appropriate analysis methods and suitable synthesis procedures. On the other hand, benefits of using GWs instead of conventional structures are required to be more clearly evidenced with high-performance GW components and proper comparatives with conventional structures. This thesis introduces several efficient analysis methods, models, and synthesis techniques that will allow engineers without significant background in GWs to straightforwardly implement GW devices. In addition, several high-performance narrow-band filters operating at Ka-band and V-band, as well as a rigorous comparative with rectangular waveguide topology, are presented. / Esta tesis aborda problemas actuales en el análisis y diseño de componentes pasivos en las bandas de onda milimétrica y Terahercios (THz). Se presentan nuevas técnicas de análisis y modelado de estructuras complejas, procedimientos de diseño, e implementación práctica de dispositivos pasivos avanzados. La primera parte de la tesis se dedica a componentes pasivos de THz. Actualmente no se disponen de guías de onda adecuadas a THz debido a que ambos, metales y dieléctricos, introducen grandes pérdidas. En consecuencia, no es adecuado escalar las estructuras metálicas cerradas usadas en microondas, ni las guías dieléctricas usadas a frecuencias ópticas. Entre un gran número de recientes propuestas, la Single Wire Waveguide (SWW) destaca por su baja atenuación y casi nula dispersión. No obstante, como guía superficial, la SWW presenta difícil excitación y radiación en curvas. El uso de un recubrimiento dieléctrico, creando la Dielecric-Coated Single Wire Waveguide (DCSWW), alivia estos inconvenientes, pero las ventajas anteriores se pierden y nuevos problemas aparecen. Hasta la fecha, no se han encontrado soluciones adecuadas para la radiación en curvas de la SWW. Además, se echa en falta una caracterización rigurosa de ambas guías. Esta tesis presenta, por primera vez, un análisis modal completo de SWW y DCSWW, adecuado a la banda de THz. Este análisis es aplicado posteriormente para evitar el problema de la radiación en curvas. Se presentan y validan experimentalmente diversas estructuras y procedimientos de diseño. La segunda parte de la tesis abarca componentes pasivos de ondas milimétricas. Actualmente, estos componentes sufren una importante degradación de su respuesta debido a que resulta difícil asegurar contacto metálico y alineamiento adecuados para la operación a longitudes de onda tan pequeñas. Además, la absorción dieléctrica incrementa notablemente a estas frecuencias. En consecuencia, tanto guías metálicas huecas como líneas de transmisión planares convencionales presentan gran atenuación, siendo necesario considerar topologías alternativas. Las Gap Waveguides (GWs), basadas en una estructura periódica que introduce un efecto de Electromagnetic Bandgap, resultan muy adecuadas puesto que no requieren contacto entre partes metálicas y evitan las pérdidas en dieléctricos. No obstante, a pesar del potencial de las GWs, varias barreras impiden la consolidación y uso universal de esta tecnología. Por una parte, la compleja topología de las GWs dificulta el proceso de diseño dado que las simulaciones de onda completa consumen mucho tiempo y no existen actualmente métodos de análisis y diseño apropiados. Por otra parte, es necesario evidenciar el beneficio de usar GWs mediante dispositivos GW de altas prestaciones y comparativas adecuadas con estructuras convencionales. Esta tesis presenta diversos métodos de análisis eficientes, modelos, y técnicas de diseño que permitirán la síntesis de dispositivos GW sin necesidad de un conocimiento profundo de esta tecnología. Asimismo, se presentan varios filtros de banda estrecha operando en las bandas Ka y V con altas prestaciones, así como una comparativa rigurosa con la guía rectangular. / Aquesta tesi aborda problemes actuals en relació a l'anàlisi i disseny de components passius en les bandes d'ona mil·limètrica i Terahercis. Es presenten noves tècniques d'anàlisi i modelatge d'estructures complexes, procediments de disseny, i implementació pràctica de dispositius passius avançats. La primera part de la tesi es focalitza en components passius de THz. Actualment no es disposen de guies d'ona adequades a THz causa que tots dos, metalls i dielèctrics, introdueixen grans pèrdues. En conseqüència, no és adequat escalar les estructures metál·liques tancades usades en microones, ni les guies dielèctriques usades a freqüències òptiques. Entre un gran nombre de propostes recents, la Single Wire Waveguide (SWW) destaca per la seua baixa atenuació i quasi nul·la dispersió. No obstant això, com a guia superficial, la SWW presenta difícil excitació i radiació en corbes. L'ús d'un recobriment dielèctric, creant la Dielecric-Coated Single Wire Waveguide (DCSWW), alleuja aquests inconvenients, però els avantatges anteriors es perden i nous problemes apareixen. Fins a la data, no s'han trobat solucions adequades per a la radiació en corbes de la SWW. A més, es troba a faltar una caracterització rigorosa d'ambdues guies. Aquesta tesi presenta, per primera vegada, un anàlisi modal complet de SWW i DCSWW, adequat a la banda de THz. Aquest anàlisi és aplicat posteriorment per evitar el problema de la radiació en corbes. Es presenten i validen experimentalment diverses estructures i procediments de disseny. La segona part de la tesi es centra en components passius d'ones mil·limètriques. Actualment, aquests components pateixen una important degradació de la seua resposta a causa de que resulta difícil assegurar contacte metàl·lic i alineament adequats per a l'operació a longituds d'ona tan menudes. A més, l'absorció dielèctrica incrementa notablement a aquestes freqüències. En conseqüència, tant guies metàl·liques buides com línies de transmissió planars convencionals presenten gran atenuació, sent necessari considerar topologies alternatives. Les Gap Waveguides (GWs), basades en una estructura periòdica que introdueix un efecte de Electromagnetic Bandgap, resulten molt adequades ja que no requereixen contacte entre parts metàl·liques i eviten les pèrdues en dielèctrics. No obstant, tot i el potencial de les GWs, diverses barreres impedixen la consolidació i ús universal d'aquesta tecnologia. D'una banda, la complexa topologia de les GWs dificulta el procés de disseny atés que les simulacions d'ona completa consumeixen molt de temps i no existeixen actualment mètodes d'anàlisi i disseny apropiats. D'altra banda, és necessari evidenciar el benefici d'utilitzar GWs mitjançant dispositius GW d'altes prestacions i comparatives adequades amb estructures convencionals. Aquesta tesi presenta diversos mètodes d'anàlisi eficients, models, i tècniques de disseny que permetran la síntesi de dispositius GW sense necessitat d'un coneixement profund d'aquesta tecnologia. Així mateix, es presenten diversos filtres de banda estreta operant en les bandes Ka i V amb altes prestacions, així com una comparativa rigorosa amb la guia rectangular. / Berenguer Verdú, AJ. (2017). Analysis and design of efficient passive components for the millimeter-wave and THz bands [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/84004
106

Low-Power Policies Based on DVFS for the MUSEIC v2 System-on-Chip

Mallangi, Siva Sai Reddy January 2017 (has links)
Multi functional health monitoring wearable devices are quite prominent these days. Usually these devices are battery-operated and consequently are limited by their battery life (from few hours to a few weeks depending on the application). Of late, it was realized that these devices, which are currently being operated at fixed voltage and frequency, are capable of operating at multiple voltages and frequencies. By switching these voltages and frequencies to lower values based upon power requirements, these devices can achieve tremendous benefits in the form of energy savings. Dynamic Voltage and Frequency Scaling (DVFS) techniques have proven to be handy in this situation for an efficient trade-off between energy and timely behavior. Within imec, wearable devices make use of the indigenously developed MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). This system is optimized for efficient and accurate collection, processing, and transfer of data from multiple (health) sensors. MUSEIC v2 has limited means in controlling the voltage and frequency dynamically. In this thesis we explore how traditional DVFS techniques can be applied to the MUSEIC v2. Experiments were conducted to find out the optimum power modes to efficiently operate and also to scale up-down the supply voltage and frequency. Considering the overhead caused when switching voltage and frequency, transition analysis was also done. Real-time and non real-time benchmarks were implemented based on these techniques and their performance results were obtained and analyzed. In this process, several state of the art scheduling algorithms and scaling techniques were reviewed in identifying a suitable technique. Using our proposed scaling technique implementation, we have achieved 86.95% power reduction in average, in contrast to the conventional way of the MUSEIC v2 chip’s processor operating at a fixed voltage and frequency. Techniques that include light sleep and deep sleep mode were also studied and implemented, which tested the system’s capability in accommodating Dynamic Power Management (DPM) techniques that can achieve greater benefits. A novel approach for implementing the deep sleep mechanism was also proposed and found that it can obtain up to 71.54% power savings, when compared to a traditional way of executing deep sleep mode. / Nuförtiden så har multifunktionella bärbara hälsoenheter fått en betydande roll. Dessa enheter drivs vanligtvis av batterier och är därför begränsade av batteritiden (från ett par timmar till ett par veckor beroende på tillämpningen). På senaste tiden har det framkommit att dessa enheter som används vid en fast spänning och frekvens kan användas vid flera spänningar och frekvenser. Genom att byta till lägre spänning och frekvens på grund av effektbehov så kan enheterna få enorma fördelar när det kommer till energibesparing. Dynamisk skalning av spänning och frekvens-tekniker (såkallad Dynamic Voltage and Frequency Scaling, DVFS) har visat sig vara användbara i detta sammanhang för en effektiv avvägning mellan energi och beteende. Hos Imec så använder sig bärbara enheter av den internt utvecklade MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). Systemet är optimerat för effektiv och korrekt insamling, bearbetning och överföring av data från flera (hälso) sensorer. MUSEIC v2 har begränsad möjlighet att styra spänningen och frekvensen dynamiskt. I detta examensarbete undersöker vi hur traditionella DVFS-tekniker kan appliceras på MUSEIC v2. Experiment utfördes för att ta reda på de optimala effektlägena och för att effektivt kunna styra och även skala upp matningsspänningen och frekvensen. Eftersom att ”overhead” skapades vid växling av spänning och frekvens gjordes också en övergångsanalys. Realtidsoch icke-realtidskalkyler genomfördes baserat på dessa tekniker och resultaten sammanställdes och analyserades. I denna process granskades flera toppmoderna schemaläggningsalgoritmer och skalningstekniker för att hitta en lämplig teknik. Genom att använda vår föreslagna skalningsteknikimplementering har vi uppnått 86,95% effektreduktion i jämförelse med det konventionella sättet att MUSEIC v2-chipets processor arbetar med en fast spänning och frekvens. Tekniker som inkluderar lätt sömn och djupt sömnläge studerades och implementerades, vilket testade systemets förmåga att tillgodose DPM-tekniker (Dynamic Power Management) som kan uppnå ännu större fördelar. En ny metod för att genomföra den djupa sömnmekanismen föreslogs också och enligt erhållna resultat så kan den ge upp till 71,54% lägre energiförbrukning jämfört med det traditionella sättet att implementera djupt sömnläge.

Page generated in 0.0297 seconds