• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 260
  • 131
  • 41
  • 20
  • 16
  • 15
  • 11
  • 10
  • 8
  • 5
  • 5
  • 4
  • 3
  • 3
  • 3
  • Tagged with
  • 620
  • 83
  • 78
  • 64
  • 62
  • 57
  • 54
  • 48
  • 46
  • 45
  • 40
  • 39
  • 38
  • 38
  • 36
  • 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.
31

A Frequency-scalable 14-bit ADC for Low Power Sensor Applications

Liang, Joshua 15 February 2010 (has links)
In this thesis, a 14-bit low-power Analog-to-Digital Converter (ADC) is designed for sensor applications. Following on previous work, the ADC is designed to be frequency scalable by 1000 times from 1.67S/s to 1.67kS/s. To reduce power, class AB opamps are used. The design was fabricated in 0.18um CMOS and occupies an area of 0.35mm2. Operating at full-rate as a Delta-Sigma modulator, the ADC achieves 91.8dB peak SNDR while consuming 83uW. In incremental mode, the ADC powers off periodically to achieve frequency scalability, maintaining 84.7dB to 89dB peak SNDR while operating from 1.67S/s to 1.67kS/s.
32

A Frequency-scalable 14-bit ADC for Low Power Sensor Applications

Liang, Joshua 15 February 2010 (has links)
In this thesis, a 14-bit low-power Analog-to-Digital Converter (ADC) is designed for sensor applications. Following on previous work, the ADC is designed to be frequency scalable by 1000 times from 1.67S/s to 1.67kS/s. To reduce power, class AB opamps are used. The design was fabricated in 0.18um CMOS and occupies an area of 0.35mm2. Operating at full-rate as a Delta-Sigma modulator, the ADC achieves 91.8dB peak SNDR while consuming 83uW. In incremental mode, the ADC powers off periodically to achieve frequency scalability, maintaining 84.7dB to 89dB peak SNDR while operating from 1.67S/s to 1.67kS/s.
33

Identification of parameters for a DC-motor by LabVIEW

Shen, Lao, Chaoran, Ye January 2012 (has links)
Abstract In this bachelor thesis we focus on how the computer software LabVIEW test is used to a DC-motor through as a hardware incremental encoder and a USB-6009. By using LabVIEW, we can do pulse counting, voltage changing test, voltage signal acquiring and some other observing jobs. This paper is a report of our mechanical operation and calculative work about the DC motor as well. The using DC motor's model number is E-660. Since we cannot find the official data of the DC motor we need, we tried to find some similar motor model to compare. Fortunately, we find some data. Even it is unofficial data from eBay website. However, these data can be seen as reference of our motor. Therefore we can compare the data from the laboratory and the theoretical ones. For the other part of the thesis is about the incremental encoder, the model we used in project is DG 63 KA. We just can find a similar type and it as a reference. The model we find similar to the actual one is DG 60L and through the measurement and comparison, we manage to test the encoder pattern is the same as the reference.     Eventually, we can still do some calculations and analysis with the measured data. We also can summarize some content according to the referential data with the similar DC motor. / 摘要 在此学士论文中我们主要将重点放在LabVIEW电脑软件测试如何通过硬件设备增量式编码器和USB-6009应用到直流电机上。通过使用LabViEW, 我们可以进行脉冲计数,电压变化测试,电压信号采样和其它观测工作。 这份报告同时也包括对直流电机的机械操作和计算工作。我们使用的直流电机型号为E-660。由于我们未能找到我们需要的直流电机的数据,我们尝试去找到一些相似的型号来比较。幸运的是,之后我们找到了一些数据。尽管数据是来自eBay的非官方数据。然而,这些数据可以作为我们电机的参考。因此我们可以使用这些理论数据和我们从实验得出的数据进行比较。 论文的另外部分是关于增量式编码器,我们在论文中使用的编码器型号是DG 63 KA。我们只能找到一些类似型号作为参考。我们找到的和实际使用的类似编码器型号为DG 60L 并且通过测量和比较,我们成功证实编码器的模式和参考中的相同。 最终,我们还对测量的数据进行了计算和分析。我们同时也根据类似的直流电机的参考数据进行总结。
34

Is emotional intelligence worthwhile?: Assessing incremental validity and adverse impact

Rhodes, Dana Lanay 15 May 2009 (has links)
Emotional intelligence is defined as the ability to perceive emotion, understand emotion, facilitate thought with emotion, and regulate emotion. Considerable debate exists as to whether emotional intelligence adds incremental validity above more wellknown predictors of performance, namely the Big Five personality traits and cognitive ability. Furthermore, no theory directly specifies the roles of separate emotional intelligence (EI) dimensions in relationship to job performance. This paper offers several contributions: (a) a summary of theoretical links between EI and job performance, (b) meta-analytic incremental validity estimation for two different conceptualizations of emotional intelligence – labeled ability EI and mixed EI – over and above cognitive ability and Big Five personality composites, (c) estimation of Black-White and femalemale adverse impact attributable to the use of EI for selection purposes, and (d) a theoretical model of EI subdimensions, demonstrating that emotion regulation mediates the effects of emotion perception and emotion understanding on job performance, and that emotional competencies serve as partial mechanisms for the effects of Conscientiousness and cognitive ability on performance.
35

Enhancement of Incremental Learning Algorithm for Support Vector Machines Using Fuzzy Set Theory

Chuang, Yu-Ming 03 February 2009 (has links)
Over the past few years, a considerable number of studies have been made on Support Vector Machines (SVMs) in many domains to improve classification or prediction. However, SVMs request high computational time and memory when the datasets are large. Although incremental learning techniques are viewed as one possible solution developed to reduce the computation complexity of the scalability problem, few studies have considered that some examples close to the decision hyperplane other than support vectors (SVs) might contribute to the learning process. Consequently, we propose three novel algorithms, named Mixed Incremental learning (MIL), Half-Mixed Incremental learning (HMIL), and Partition Incremental learning (PIL), by improving Syed¡¦s incremental learning method based on fuzzy set theory. We expect to achieve better accuracy than other methods. In the experiments, the proposed algorithms are investigated on five standard machine learning benchmark datasets to demonstrate the effectiveness of the method. Experimental results show that HIL have superior classification accuracy than the other incremental or active learning algorithms. Especially, for the datasets that might have high accuracy in other research reports, HMIL and PIL could even improve the performance.
36

Simulation study of optimum control for a rocker system

Sha, Jilun. January 1984 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 76-79).
37

GRAPE : parallel graph query engine

Xu, Jingbo January 2017 (has links)
The need for graph computations is evident in a multitude of use cases. To support computations on large-scale graphs, several parallel systems have been developed. However, existing graph systems require users to recast algorithms into new models, which makes parallel graph computations as a privilege to experienced users only. Moreover, real world applications often require much more complex graph processing workflows than previously evaluated. In response to these challenges, the thesis presents GRAPE, a distributed graph computation system, shipped with various applications for social network analysis, social media marketing and functional dependencies on graphs. Firstly, the thesis presents the foundation of GRAPE. The principled approach of GRAPE is based on partial evaluation and incremental computation. Sequential graph algorithms can be plugged into GRAPE with minor changes, and get parallelized as a whole. The termination and correctness are guaranteed under a monotonic condition. Secondly, as an application on GRAPE, the thesis proposes graph-pattern association rules (GPARs) for social media marketing. GPARs help users discover regularities between entities in social graphs and identify potential customers by exploring social influence. The thesis studies the problem of discovering top-k diversified GPARs and the problem of identifying potential customers with GPARs. Although both are NP- hard, parallel scalable algorithms on GRAPE are developed, which guarantee a polynomial speedup over sequential algorithms with the increase of processors. Thirdly, the thesis proposes quantified graph patterns (QGPs), an extension of graph patterns by supporting simple counting quantifiers on edges. QGPs naturally express universal and existential quantification, numeric and ratio aggregates, as well as negation. The thesis proves that the matching problem of QGPs remains NP-complete in the absence of negation, and is DP-complete for general QGPs. In addition, the thesis introduces quantified graph association rules defined with QGPs, to identify potential customers in social media marketing. Finally, to address the issue of data consistency, the thesis proposes a class of functional dependencies for graphs, referred to as GFDs. GFDs capture both attribute-value dependencies and topological structures of entities. The satisfiability and implication problems for GFDs are studied and proved to be coNP-complete and NP-complete, respectively. The thesis also proves that the validation problem for GFDs is coNP- complete. The parallel algorithms developed on GRAPE verify that GFDs provide an effective approach to detecting inconsistencies in knowledge and social graphs.
38

Uma Abordagem Semi-automática para Geração Incremental de Correspondências entre Ontologias / A Semi-Automatic approach for generating incremental correspondences between ontologies

Hortêncio Filho, Fernando Wagner Brito January 2011 (has links)
HORTÊNCIO FILHO, Fernando Wagner Brito. Uma Abordagem Semi-automática para Geração Incremental de Correspondências entre Ontologias. 2011. 81 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências, Departamento de Computação, Fortaleza-CE, 2011. / Submitted by guaracy araujo (guaraa3355@gmail.com) on 2016-06-27T19:11:59Z No. of bitstreams: 1 2011_dis_fwbhortênciofilho.pdf: 2807164 bytes, checksum: f2d22503112321ee69d172f0ac56d4c8 (MD5) / Approved for entry into archive by guaracy araujo (guaraa3355@gmail.com) on 2016-06-27T19:14:07Z (GMT) No. of bitstreams: 1 2011_dis_fwbhortênciofilho.pdf: 2807164 bytes, checksum: f2d22503112321ee69d172f0ac56d4c8 (MD5) / Made available in DSpace on 2016-06-27T19:14:07Z (GMT). No. of bitstreams: 1 2011_dis_fwbhortênciofilho.pdf: 2807164 bytes, checksum: f2d22503112321ee69d172f0ac56d4c8 (MD5) Previous issue date: 2011 / The discovery of semantic correspondences between schemas is an important task for different fields of applications such as data integration, data warehousing and data mashup. In most cases, the data sources involved are heterogeneous and dynamic, making it even harder the performance of that task. Ontologies are being used in order to define common vocabulary used to describe the elements of the schemas involved in a particular application. The problem of matching between ontologies, or ontology matching, consists in the discovery of correspondences between terms of vocabularies (represented by ontologies) used between the various applications. The solutions proposed in the literature, despite being fully automatic have heuristic nature, and may produce non-satisfactory results. The problem intensifies when dealing with large data sources. The purpose of this paper is to propose a method for generation and incremental refinement of correspondences between ontologies. The proposed approach makes use of filtering techniques of ontologies, as well as user feedback to support the generation and refining these matches. For validation purposes, a tool was developed and experiments were conducted / A descoberta de correspondências semânticas entre esquemas é uma importante tarefa para diversos domínios de aplicações, tais como integração de dados, data warehouse e mashup de dados. Na maioria dos casos, as fontes de dados envolvidas são heterogêneas e dinâmicas, dificultando ainda mais a realização dessa tarefa. Ontologias vêm sendo utilizadas no intuito de definir vocabulários comuns usados para descrever os elementos dos esquemas envolvidos em uma determinada aplicação. O problema de matching entre ontologias, ou ontology matching, consiste na descoberta de correspondências entre os termos dos vocabulários (representados por ontologias) usados entre as diversas aplicações. As soluções propostas na literatura, apesar de serem totalmente automáticas possuem natureza heurística, podendo produzir resultados não-satisfatórios. O problema se intensifica quando se lida com grandes fontes de dados. O objetivo deste trabalho é propor um método para geração e refinamento incremental de correspondências entre ontologias. A abordagem proposta faz uso de técnicas de filtragem de ontologias, bem como do feedback do usuário para dar suporte à geração e ao refinamento dessas correspondências. Para fins de validação, uma ferramenta foi desenvolvida e experimentos foram realizados.
39

Potentialities of the use of incremental forming in Computer Aided Design and manufacture of customized craniofacial implants

Bertol, Liciane Sabadin January 2012 (has links)
Operationen im Schädel‐ und Gesichtsbereich stellen nach wie vor eine große Herausforderung für die behandelnden Ärzte dar, weil sich oftmals die Abgrenzung des Knochendefekts und die Wiederherstellung der ursprünglichen Knochenstruktur als schwierig erweisen. Die erste Herausforderung dabei ist die Definition der Implantatgeometrie, da jeder Patient eine individuelle Anatomie und, im Falle eines Knochendefekts durch Traumata oder Tumore, jeder Defekt eine spezifische Form aufweist. Das Implantat sollte somit eine der originalen Knochenstruktur entsprechenden Geometrie besitzen und aus einem für die Implantation geeigneten Material bestehen. Weiterhin muss das für die Herstellung des Implantats gewählte Verfahren derart anpassungsfähig sein, dass auch die Erzeugung eines einzelnen individuellen Produktes möglich ist und keine übermäßigen Kosten im Werkzeug‐ und Formenbau verursacht werden. Im gegenwärtigen Szenario flexibler Herstellungsprozesse, die eine effiziente Blechumformung auch in kleineren Stückzahlen erlauben, liegt ein besonderer Schwerpunkt auf dem Verfahren der inkrementellen Umformung. In dieser Arbeit wird daher die Durchführbarkeit der präoperativen Herstellung individueller Implantate zur Wiederherstellung knöcherner Strukturen verschiedener Regionen im Schädel‐ und Gesichtsbereich mit dem Verfahren der inkrementellen Blechumformung untersucht. Dabei wurden unterschiedliche Methoden zur Modellierung von Implantaten aus patientenspezifischen CT‐Daten angewendet und Prozessparameter für die Herstellung verschiedener Formen von Titanimplantaten entwickelt. Ferner werden alternative Techniken vorgestellt, mit denen es ebenfalls möglich ist, solche Implantate herzustellen. Gleichwohl es Einschränkungen hinsichtlich der Formgenauigkeit und Komplexität der zu formenden Geometrie des Implantates gibt, zeigt diese Arbeit, dass das Verfahren der inkrementellen Blechumformung eine geeignete Alternative für die präoperative Herstellung von individuellen Implantaten für den Schädel‐ und Gesichtsbereich darstellt. / Atualmente, cirurgias de reconstrução craniofacial ainda são um desafio à equipe cirúrgica devido às dificuldades em definir e reparar o defeito ósseo. A definição da geometria do implante é o primeiro desafio, uma vez que cada paciente possui uma anatomia individual e, em caso de defeitos ósseos devido a traumas ou tumores, cada defeito possui uma forma específica. O implante deve, então, possuir geometria tal que o possibilite substituir a estrutura original e ser constituído de material apto para a implantação. Além disso, o processo de fabricação selecionado deve ser flexível a fim de possibilitar a produção de uma peça única, dispensando custos excessivos com ferramental. No cenário atual de processos de manufatura flexível, um destaque especial recebe o processo de estampagem incremental, que permite a conformação de chapas metálicas para a fabricação de pequenos lotes. Neste sentido, este estudo ocorre no âmbito da fabricação pré‐operatória de implantes personalizados para reparo de defeitos em diferentes regiões do complexo craniofacial através do processo de estampagem incremental. Foram utilizados diferentes procedimentos para modelagem dos implantes a partir de dados tomográficos e foram desenvolvidos parâmetros para a conformação de diferentes geometrias em titânio. São apresentadas, ainda, técnicas alternativas capazes de produzir tais implantes. O estudo mostra que, embora possua precisão dimensional limitada e restrições com relação à complexidade geométrica dos implantes que podem ser conformados, o processo de estampagem incremental apresenta‐se como uma alternativa viável à fabricação pré‐operatória de implantes personalizados para a reconstrução de defeitos craniofaciais. / Currently, craniofacial reconstruction surgeries are still a challenge for surgical teams due to the difficulty to define and repair bone defects. Defining the geometry of the implant is the first challenge, since each patient has an individual anatomy and, in case of bone defects due to trauma or tumors, each defect has a specific shape. The implant should then have a geometry that permits the replacement of the original structure and should consist of a material suitable for implantation. Moreover, the selected manufacturing process must be flexible enough to enable the production of a single piece, not requiring excessive cost with dyes and tooling. In the current scenario of flexible manufacturing processes, the process of incremental forming, which permits forming metal sheets to manufacture small batches, receives special emphasis. Thus, this study evaluates the feasibility of preoperative manufacturing of customized implants to repair defects in different regions of the craniofacial complex through the process of incremental forming. Different procedures were used for modeling implants obtained from CT data of patients and the parameters for forming different geometries of titanium implants were developed. Alternative techniques capable of producing such implants are also presented. The study shows that, although it has limited dimensional accuracy and restrictions regarding the geometric complexity of the implants that can be shaped, the single point incremental forming (SPIF) process represents a suitable alternative for the preoperative manufacturing of customized implants for the reconstruction of craniofacial defects.
40

Modelos incrementais para plasticidade cíclica : um estudo numérico

Silva Filho, Carlos Magno Lopes da 29 July 2016 (has links)
Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2016. / Submitted by Fernanda Percia França (fernandafranca@bce.unb.br) on 2016-08-16T15:59:55Z No. of bitstreams: 1 2016_CarlosMagnoLopesdaSilvaFilho.pdf: 4227558 bytes, checksum: 2aa236bfafa1105c8fb0b5fd4c5a6c10 (MD5) / Approved for entry into archive by Raquel Viana(raquelviana@bce.unb.br) on 2016-09-05T20:02:35Z (GMT) No. of bitstreams: 1 2016_CarlosMagnoLopesdaSilvaFilho.pdf: 4227558 bytes, checksum: 2aa236bfafa1105c8fb0b5fd4c5a6c10 (MD5) / Made available in DSpace on 2016-09-05T20:02:35Z (GMT). No. of bitstreams: 1 2016_CarlosMagnoLopesdaSilvaFilho.pdf: 4227558 bytes, checksum: 2aa236bfafa1105c8fb0b5fd4c5a6c10 (MD5) / Apresenta-se um estudo sobre modelos para descrição do comportamento elastoplástico sob condições de carregamento cíclico uniaxial e multiaxial, proporcional e não proporcional. Em particular, foca-se na versão original proposta por Jiang em 1993, que inova sobre o modelo de Chaboche pela consideração de uma superfície de memória que define o tamanho do domínio elástico em função da amplitude de carregamento. As consequências da consideração da superfície de memória sobre a observação ou não do efeito de Masing são discutidas. O modelo de Jiang, em sua versão original, mostra boa aderência em relação a resultados experimentais uniaxiais, mas exibe encruamento menor do que aqueles observados experimentalmente no caso de carregamentos não proporcionais. _________________________________________________________________________________________________ ABSTRACT / A study on models for the description of the elastoplastic behaviour under conditions of uniaxial and multiaxial, proportional and non proportional cyclic loadings is presented. In particular, the study focuses on the original version of the model proposed by Jiang in 1993. The Jiang´s model inovates upon the one proposed by Chaboche by considering a memory surface witch dictates the size of the elastic domain as a function of the loading amplitude. The consequences of the memory surface over the observation or not over the Masing efect are discussed. The modelo of Jiang in the original version shows good responses at uniaxial results, but shows hardening lower than observed experimentally for the non proportional cases.

Page generated in 0.0848 seconds