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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.
31

On Envelopes and Extraneous Loci of Differential Equations of Order One and Higher Degree

Lane, Hal Burns 08 1900 (has links)
The purpose of this paper is to examine the properties of the envelope and the extraneous loci associated with the solution curves of ordinary differential equations of the first order and degree greater than one.
32

Envelopes of adaptation - an architecture of social thresholds and flexibility: investigating the socio-technical relationship between the built edge and social surface

Moodley, Byron January 2018 (has links)
The concept of adaptability in architecture is one that very often bears technical rather than social connotations. What are the mechanisms and systems that allow buildings to adapt to fluctuating environmental and climatic conditions? These responses are often the driving force behind design considerations, placing emphasis on the manner in which the technical resolutions facilitate appropriate adaptability and environmental response. This adaptability is generally addressed through the building envelope, which acts as the mediator between the interior conditions of a building, and the exterior conditions of its environment (Lovell, 2010). However, beyond addressing these environmental conditions, there are greater urban and social conditions that bear equal weight within any design inquiry. Building adjacencies, ethnographics, social development and imageability of spatial ordering are all fundamental factors that need to be addressed within building envelope design (Lovell, 2010). The design dissertation inquiry explores the multi-faceted nature of building envelopes as well as an architecture of internal and external thresholds. The inquiry examines ways in which building envelopes respond to both the environmental and social complexities of a context, as well as how internal and external threshold and edge conditions can be design generative and communicative; expressing spatial organisations, conditions of privacy and mechanisms of adaptability. This topic of adaptive envelopes and defining thresholds in relation to social complexities has been explored in an architectural design project, which aims to practically address social and environmental issues. This exploration yields a set of key findings into an architecture of thresholds and adaptability in response to the sociotechnical conditions of a context where the lines between the formal and informal are blurred.
33

ENVELOPE MODEL FOR MULTIVARIATE LINEAR REGRESSION WITH ELLIPTICAL ERROR

Alkan, Gunes, 0000-0001-9356-2173 January 2021 (has links)
In recent years, the need for models which can accommodate higher order covariates have increased greatly. We first consider linear regression with vector-valued response Y and tensor-valued predictors X. Envelope models (Cook et al., 2010) can significantly improve the estimation efficiency of the regression coefficients by linking the regression mean with the covariance of the regression error. Most existing tensor regression models assume that the conditional distribution of Y given X follows a normal distribution, which may be violated in practice. In Chapter 2, we propose an envelope multivariate linear regression model with tensor-valued predictors and elliptically contoured error distributions. The proposed estimator is more robust to violations of the error normality assumption, and it is more efficient than the estimators without considering the underlying envelope structure. We compare the new proposal with existing estimators in extensive simulation studies. In Chapter 3, we explore how the missing data problem can be addressed for multivariate linear regression setting with envelopes and elliptical error. A popular and efficient approach, multiple imputation is implemented with bootstrapped expectation-maximization (EM) algorithm to fill the missing data, which is then followed with an adjustment in estimating regression coefficients. Simulations with synthetic data as well as real data are presented to establish the superiority of the adjusted multiple imputation method proposed. / Statistics
34

Communication without words: Understanding the implications of temporal structure for auditory perception

Gillard, Jessica 08 October 2014 (has links)
Amplitude envelope is an important aspect of auditory perception. As one article included (Chapter 3) goes into great detail regarding this, it will not be discussed here. Included are two articles that explore the importance and influence of amplitude envelope in auditory perception research. The first article (Chapter 2) explores the role of amplitude envelope in an associative memory task, with the aim of improving the associability of auditory alarms in medical devices. Although we found no difference in performance based on amplitude envelope, the paper discusses the patterns of incorrect alarm identification and identifies potential sources of confusion. While this was not our initial goal, we feel this article is a valuable contribution that connects two distinct fields: music cognition and alarm design. The second article (Chapter 3) encompasses a meta-analysis, surveying the temporal structure of sounds used in auditory perception research, namely in the journal Attention, Perception & Psychophysics. This articles discusses several studies in which amplitude envelope has categorically influenced experimental outcomes and suggests that the standard ‘flat’ temporal structure (i.e. abrupt onset, period of sustain and abrupt offset) may not be the best way to evaluate the auditory system. The goal of this article is to determine what proportion of studies are using the standard ‘flat’ tones vs. other types of temporal structures we may encounter during everyday listening. These two articles collectively illustrate the original research I have completed on amplitude envelope during my Master’s Degree. / Thesis / Master of Science (MSc)
35

GEAR MODELING BY SIMULATING THE FABRICATION PROCESS

NAIR, DEEPA 13 July 2005 (has links)
No description available.
36

Evaluating the effects of amplitude envelope manipulation on reducing auditory alarm annoyance

Sreetharan, Sharmila January 2019 (has links)
Auditory alarm annoyance plagues clinicians, which results in alarms desensitization and ultimately affects patient care. Contributing to this problem are the International Electrotechnical Commission (IEC) 60601-1-8 alarms, a standardized set of melodic alarms used to convey information to clinicians in intensive care units. By design, IEC alarms employ flat amplitude (i.e., amplitude invariant) envelopes and are not reflective of naturally occurring sounds with percussive amplitude (i.e., decaying) envelopes. We present a series of three experiments evaluating the effect of amplitude envelope manipulation (i.e., incorporating percussive envelope) on memory and annoyance in IEC alarms synthesized using pure tones (experiment 1), complex tones (experiment 2) and assessing annoyance pre and post memory assessment (experiment 3). For the memory assessment, participants were assigned to learn either the flat alarms or percussive alarms. During the memory assessment, participants were informed of the alarm–referent pairings (study phase), practised identifying alarms (training phase), had a short break, and tested on their ability to identify alarms (evaluation phase). The annoyance assessment was a two alternative forced choice task where participants identified which alarm they perceived to be more annoying from a pair of alarms differing in either envelope-type or alarm-type. Across all experiments there was no difference in alarm learnability between those learning either flat or percussive alarms during the memory assessment. Annoyance assessments revealed that all participants chose the flat alarms to be more annoying than the percussive alarms, independent of the memory assessment condition. These results showcase the potential of using percussive alarms to reduce alarm annoyance without harming learnability, a cost-efficient manipulation. / Thesis / Master of Science (MSc) / Alarms in intensive care units are perceived as annoying, ultimately negatively affecting both clinicians and patients. These alarms are mandated by the International Electrotechnical Commission to have sustained or flat amplitude envelopes (i.e., referring to the change in loudness over time), which does not reflect naturally occurring stimuli that typically have decaying or percussive amplitude envelopes. The current experiments assessed the effect of percussive envelopes on alarm learnability and annoyance. We showed in a series of experiments that there is no difference in learning alarms with flat or percussive envelopes. However, we showed that alarms with percussive envelopes are perceived to be less annoying than alarms with flat envelopes. These results offer one potential solution to reduce alarm annoyance in intensive care units without harming the learnability of these alarms.
37

AFFORDABLE, ALTERNATIVE TEST METHOD FOR MEETING CIVIL AVIATION REDUCED VERTICAL SEPARATION MINIMUM (RVSM) REQUIRMENTS ON MILITARY/COMMERCIAL AIRCRAFT

Pratt, Robert L. 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / A recent Air Traffic Management (ATM) initiative has reduced certain oceanic routes from a 2,000-foot vertical separation minimum to a 1,000-foot (300 m) separation minimum between flight levels of 29,000 feet and 41,000 feet. As a result of this initiative, an aircraft transitioning from the Continental United States (CONUS) to Europe or Asia will be required to have a validated, certified altimeter reporting system within the specified tolerances. The aging military airframes are not currently Reduced Vertical Separation Minimum (RVSM) certified. The impact on military deployment time to foreign theatres as well as high- fuel cost makes this a high-priority DoD issue. This paper describes the test and evaluation (T&E) challenge, viable solutions and test method for meeting the RVSM requirements in an approved, affordable, and least down-time (minimal aircraft modification) manner. The test method described herein utilizes a PACER aircraft in formation with the RVSM candidate aircraft. The RVSM is just one of the many Global Air Traffic Management (GATM) requirements which must be met for military aircraft to fly within premium airspace during overseas deployment. The commercial equivalent of GATM is Communications Navigation and Surveillance/Air Traffic Management (CNS/ATM). Our focus will be on meeting the RVSM certification requirements as related to the test environment.
38

Optimisation conjointe de méthodes de linéarisation de l'émetteur pour des modulations multi-porteuses / Joint optimization of transmitter linearization methods in multi-carrier modulations context

Brandon, Mathilde 08 November 2012 (has links)
Les modulations multiporteuses apparaissent aujourd'hui comme une technologie éprouvée pour la transmission de données à haut-débits sur des canaux pouvant être très perturbés. L'OFDM (Orthogonal Frequency Division Multiplexing) a d'ailleurs été choisie dans plusieurs normes de télécommunications (ADSL, Wi-Max, IEEE 802.11a/g/n, LTE, DVB,...). Cependant un des inconvénients de ce type de modulation est la forte variation de la puissance instantanée à transmettre. Cette propriété rend ces modulations très sensibles aux non-linéarités des composants analogiques, en particulier celles de l'amplificateur de puissance à l'émission. Or l'amplificateur de puissance est un élément déterminant dans une chaîne de communication dans la mesure où il a une influence prépondérante sur le bilan global de la transmission en termes de puissance, de rendement et de distorsion. Plus l'on souhaite que l'impact de ses non linéarités soit faible et plus son rendement est faible, et inversement. Il est donc nécessaire d'effectuer un compromis linéarité/rendement.L'objectif de la thèse est d'éviter cette détérioration du rendement tout en conservant de bonnes performances de linéarité, de surcroit pour des signaux OFDM. Pour ce faire nous proposons d'utiliser conjointement des méthodes de linéarisation (prédistorsion numérique en bande de base) et d'amélioration du rendement (envelope tracking) de l'amplificateur de puissance ainsi qu'une méthode de réduction de la dynamique du signal (active constellation extension). La prédistorsion numérique classique échouant aux fortes puissances, nous proposons une méthode d'amélioration de cette technique à ces puissances. Nos résultats sont validés par des mesures sur un amplificateur de puissance 50W. Nous proposons également une association des méthodes permettant d'améliorer simultanément les performances en terme de linéarité hors bande et de rendement en minimisant les dégradations des performances de taux d'erreur binaire. / Multi-carrier modulations appear as a well-tried technology for high-speed data transmission on potentially disrupted channels. OFDM (Orthogonal Frequency Division Multiplexing) has been chosen for that matter in several telecommunication standards (ADSL, Wi-Max, IEEE 802.11a/g/n, LTE, DVB,...). However one of the drawbacks of this modulation type is its high variation of the instantaneous power to transmit. This property makes these modulations very sensitive to the non-linearities of analog components, especially those related to power amplifiers. Yet the power amplifiers are critical elements in the communication chain as they have a major influence on the global assessment in terms of power, efficiency and distortion. More we want its non linearity impact is weak, more its efficiency is weak too. It is therefore necessary to make a trade-off between linearity and efficiency.The purpose of the thesis is to avoid this efficiency damage keeping at the same time the good linearity performance, moreover for OFDM signals. In this way we propose to jointly use a linearization technique (the base band digital predistortion) and a technique of efficiency improvement (the envelope tracking) for the power amplifier, together with a technique of signal dynamic reduction (the active constellation extension). The classic predistortion failing for high powers, we propose an improvement of this technique for these powers. Our results are validated by measurements on a 50W power amplifier. We also propose an association of the techniques allowing an improvement of the performance in terms of out-of-band linearity and efficiency, with smallbit error rate damages.
39

Desenvolvimento de métodos sorológicos para diagnóstico de infecções pelos vírus Chikungunya e Mayaro / Development of methods for serological diagnose of Chikungunya and Mayaro infections

Fumagalli, Marcílio Jorge 14 May 2018 (has links)
Devido a existência de 2 alphavírus artritogênicos no Brasil, os vírus Mayaro (MAYV) e Chikungunya (CHIKV) tornou-se importante desenvolver testes diagnósticos eficazes para discriminar suas infecções. No presente trabalho, desenvolvemos ELISAs indiretos para diagnóstico de CHIKV e MAYV utilizando proteínas de envelope viral E2 recombinantes, produzidas em Escherichia coli, as rE2-CHIKV e rE2-MAYV ELISAs. As proteínas E2 recombinantes tiveram suas antigenicidades verificadas nos ensaios utilizando anticorpos policlonais oriundos de camundongos hiperimunizados com CHIKV, MAYV e outros alphavírus. O rE2-CHIKV ELISA detectou anticorpos murinos de forma homotípica e não produziu reações cruzadas evidenciáveis utilizando anticorpos murinos específicos contra outros Alphavírus. O rE2-MAYV ELISA detectou anticorpos murinos homotípicos e também, reagiu cruzadamente com anticorpos murinos anti-CHIKV, mas não para outros Alphavírus. Esses ELISAs, também, foram usados na detecção de anticorpos em soros de pacientes com suspeita de infecção arboviral. Pelo o rE2-CHIKV ELISA, testaram-se 59 soros, resultando em 26 amostras IgG positivas. Resultados desse ELISA, quando comparados aos obtidos por teste de neutralização, demonstraram sensibilidade de 89,66% e especificidade de 100%. Soros humanos IgG positivos foram detectados em altas diluições pelo rE2-CHIKV ELISA. Quanto a detecção de IgM, o rE2- CHIKV ELISA apresentou moderada concordância com outros ensaios sorológicos. Com rE2- MAYV ELISA, testaram-se 68 soros resultando em 23 amostras IgG positivas, das quais 11 também mostraram-se positivas em teste de neutralização, demonstrando sensibilidade de 100% e especificidade de 78,95%. Portanto, os rE2-CHIKV e rE2 MAYV ELISAs, particularmente para detecção de IgG, mostraram-se adequadamente sensíveis e específicos para serem validados em estudos com maiores números de amostras e serem aplicados ao diagnóstico de pacientes infectados com CHIKV e MAYV. / Due the existence of 2 arthritogenic alphaviruses in Brasil, the viruses Mayaro (MAYV) and Chikungunya (CHIKV), it became important the development of efficient diagnose tests to discriminate their infections. In the present work, we developed indirect ELISAs for CHIKV and MAYV diagnosis using viral recombinant envelope proteins E2, produced in Escherichia coli, the rE2-CHIKV and rE2-MAYV. The recombinant E2 proteins had their antigenicity confirmed in the assay by using polyclonal antibodies produced in hyperimmunized mice with CHIKV, MAYV and other alphaviruses. The rE2-CHIKV ELISA detected homotypic murine antibodies and did not produced detectable cross-reactivity signal when using murine antibodies from other alphaviruses. The rE2-MAYV ELISA detected homotypic antibodies and also cross-reacted with murine anti-CHIKV antibodies, but not to other alphaviruses. These ELISAs were also tested for the detection of human antibodies, using patient sera suspected of arboviral infection. For rE2- CHIKV ELISA, it were tested 59 sera, resulting in 26 positive IgG samples. These ELISA results, when compared to those of a neutralizing assay, demonstrated a sensibility of 89.66% and specificity of 100%. The IgG positive human sera were detected in high dilutions by rE2-CHIKV ELISA. Regarding the detection of IgM, the rE2-CHIKV ELISA showed a moderate samples detection agreement when compared to other serologic assays. For rE2-MAYV ELISA, it were tested 68 sera, resulting in 23 positive IgG samples, of which 11 demonstrated to be positive by the neutralization assay, demonstrating a sensibility of 100% and specificity of 78.95%. Therefore, the rE2-CHIKV and rE2-MAYV ELISAs, especially for IgG detection, demonstrated to be properly sensitive and specific to be validated in studies using a greater number of samples, and also to be applied in the diagnosis of infected CHIKV and MAYV patients.
40

Identificação de epítopos presentes na proteína e do vírus dengue tipo 2 (DENV2) capazes de gerar anticorpos neutralizantes sem a promoção da exacerbação da replicação viral. / Identification of epitopes present in the E protein of dengue virus type 2 (DENV2) capable of generating neutralizing antibodies without causing exacerbation of viral replication.

Maeda, Denicar Lina Nascimento Fabris 04 September 2018 (has links)
A dengue é uma doença causada por um dos quatro sorotipos de vírus da dengue (DENV 1-4), e representa a principal arbovirose que atualmente atinge seres humanos. Dentre as maiores dificuldades para o desenvolvimento de uma vacina eficaz contra o DENV, correlaciona-se a falta de conhecimento mais preciso sobre os epítopos presentes na superfície do vírus, responsáveis para indução de anticorpos neutralizantes sem promoverem a exacerbação da infecção viral. Desta forma, o objetivo do presente trabalho foi identificar epítopos presentes na superfície do DENV2 capazes de gerar anticorpos neutralizantes sem promover a amplificação viral frente a células que expressem receptores FcR. Avaliamos também a influência dos adjuvantes (LT, LT-K63 e LTB), na modulação da resposta de anticorpos para epítopos presentes nos domínios I, II e III da proteína de envelope do DENV2. Observamos que a administração das LTs como adjuvantes proporcionaram a potencialização da resposta de anticorpos IgG EDI/II ou EDIII-específicos nos animais imunizados, em relação aos outros grupos vacinais. Em relação à qualidade da resposta humoral proporcionada pelas imunizações, os anticorpos antígeno-específicos gerados com LT, LT-K63 ou LTB apresentaram maior capacidade de neutralização viral em comparação com aqueles obtidos dos demais grupos vacinais. Demonstramos de forma inédita através da análise de imunoassinatura dos anticorpos IgG EDIII-específicos, que a administração de LT e LTB como adjuvante vacinal, permitiu a identificação de um epítopo localizado na alça EF e FG da proteína EDIII de DENV2. Além disso, por meio da utilização de um peptídeo 47 contendo a sequência correspondente ao epítopo identificado, foi capaz de inibir a infecção do DENV2, tão bem quanto, a proteína EDIII em ensaios in vitro. Podemos perceber, que a utilização do adjuvante LT e seu derivado atóxico LTB em formulações vacinais, possibilitaram a modulação de anticorpos capazes de reconhecer epítopos presentes no EDIII, importantes para a neutralização viral. Esses resultados, permitem o desenvolvimento de novos antígenos alvos para estratégias vacinas voltadas para o controle dos DENV. / Dengue is a disease caused by one of four dengue virus serotypes (DENV 1-4), represents the main arbovirose that currently affects humans. Among the greatest difficulties for the development of effective vaccine against DENV is the lack of more precise knowledge about the epitopes present at the surface of the virus, responsible for the induction of neutralizing antibodies without promoting the exacerbation of viral infection. Thus, the objective of the present work was to identify epitopes present on the surface of DENV2 capable of generating neutralizing antibodies without promoting viral amplification against cells expressing the FcR receptors. We also evaluated the influence of adjuvants (LT, LT-K63 and LTB) on the modulation of the antibody response to epitopes present in domains I, II and III in envelope protein of DENV2. We have observed that administration of LTs as adjuvants provided potentialization of the antibodies response IgG EDI/II or EDIII-specific in the immunized animals, relative to the other vaccine groups. Regarding the quality of the humoral response provided by the immunizations, the antigen-specific antibodies generated with LT, LT-K63 or LTB presented higher viral neutralization capacity compared to those obtained from the other vaccine groups. We demonstrated through the immunoassay analysis of EDIII-specific IgG antibodies that the administration of LT and LTB as a vaccine adjuvant allowed the identification of an epitope located in the EF and FG loop of the EDIII protein of DENV2. Furthermore, by using a peptide 47 containing the sequence corresponding to the identified epitope, was able to inhibit DENV2 infection as well as the EDIII protein in vitro assays. It can be seen that the use of the LT adjuvant and its non-toxic derivative LTB in vaccine formulations enabled the modulation of antibodies capable of recognizing epitopes present in EDIII, which are important for viral neutralization. These results allow the development of new target antigens for vaccine strategies aimed at the control of DENV.

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