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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.
691

TRANSPARENCE ACOUSTIQUE DE DOUBLES PAROIS REMPLIES DE MATÉRIAUX GRANULAIRES.

Chazot, Jean-Daniel 13 December 2006 (has links) (PDF)
Une étude théorique, basée sur la méthode des mobilités de surface, et expérimentale de la transparence acoustique des doubles parois est présentée. L'étude de la diffusivité du champ acoustique pariétal d'excitation est aussi réalisée à l'aide d'un nouvel indice permettant d'expliquer la dispersion des mesures de transparence acoustique inter-laboratoires. L'ajout de matériaux granulaires est ensuite étudié, et un modèle basé sur une simplification du modèle de Biot est proposé. Il permet d'utiliser une méthode de résolution très performante en terme de temps de calcul. Des méthodes de mesure inverse sont alors utilisées afin de déterminer les caractéristiques de ces matériaux, et donnent des résultats probants. Enfin, l'amélioration de l'isolation acoustique par optimisation de la position de liens mécaniques est étudiée, et les solutions théoriques sont ensuite testées expérimentalement.
692

Diskriminering på arbetsplatsen baserad på arbetstagarens vikt. : En psykologisk studie

Quist, Charlotte January 2009 (has links)
<p>Abstrakt</p><p>Syftet med denne undersökelsen var å se om det fantes et samband mellom lönn og vekt og utenforskap og vekt inom kriminalvården og det ble sjekket om extroversion, kjönn og alder hadde noen påvirkning på dette. Det ble brukt en delvis selvkonstruert enkät med 22 av  Eysenck´s extraversionsspörsmål (Eysenck & Eysenck, 1975). Det ble konstruert spörsmål om utenforskap og fysikk og stilt spörsmål om lönn, vekt og alder. Dette ble gjort  for å se om det fantes et  samband mellom disse faktorene. Personene som var med i denne studien jobbet alle inom kriminalvården (<em>n</em>=48), 21 kvinner og 27 menn med en middelalder på 42,91 år (<em>sd=</em>12,46<em>)</em>. Studien er gjort på grunnlag av ulike studier som viser at det finnes et signifikant  samband mellom lönn og vekt, vekt og extraversion og vekt og utenforskap, og at det finnes utpregede negative stereotyper om overvektige personer. Funnene i denne studie viste ikke det samme som  andre studier viser når det gjelder lönn og vekt; det fantes ikke noen signifikant samband mellom disse variablene. Det fantes derimot et signifikant negativt samband mellom vekt og utenforskap. Dette kan indikere at inom kriminalvården ses det ikke  på som noe negativt om man har höyere vekt men kanskje mer som en styrke i den daglige interaksjonene med intagna.</p><p><em>Nökkelord: Ekstraversion, utenforskap, stereotyper, overvekt, diskriminering</em></p><p> </p> / <p>Abstract</p><p>The aim of this study was to examine the relationship between salary and weight and social isolation and weight for prison officers and to see if extraversion, gender and age had any influence on these. The instrument that was used was a partly self-designed questionnaire with 22 of Eysenck´s questions about extraversion (Eysenck &  Eysenck, 1975).  Questions were designed to measure the feeling of social isolation and physical condition, questions were asked about wages, weight and age to see if there were any significant relationship between these factors. The  people who worked in  treatment of offenders (N=48) were part of this study, 21 women and 27 men with a mean age of 42,91 years (<em>std</em>=12,46). This study was done on the basis of different studies that show a significant relationship between salary and weight, weight and extraversion and weight and the feeling of social isolation, and that larger people are stereotypically viewed negatively. The findings in this study however show something else than the other studies show concerning salary and weight; it was no significant relationship  between these variables. Between weight and the feeling of social isolation however, a negative significant relationship was found. This can indicate that it doesn´t  have to be negative to be large bodied when working with prisoners but maybe it is seen as an asset in the daily intervention with the inmates.</p><p><em>Keywords: Extraversion, social isolation, stereotyping, overweight, discrimination.</em></p>
693

Managing signal and power integrity using power transmission lines and alternative signaling schemes

Telikepalli, Satyanarayana 08 June 2015 (has links)
In this dissertation, a new signaling scheme known as Constant Voltage Power Transmission Line (CV-PTL) is presented to supply power to a digital I/O circuit. This signaling scheme provides power through a transmission line in place of a power plane while dynamically changing the impedance of the power delivery network to keep a constant voltage at the power pin of the IC. Consequently, this reduces the effects of return path discontinuities and can improve the quality of output signal by reducing power and ground bounce. Through theory, simulation, and measurements, we show that this new method can be used to reduce jitter and eye height with the proposed PDN methodology. In addition, the signaling scheme was extended to vertically-stacked 3D integrated circuits (3D ICs). It is known that power supply noise worsens as one goes higher up in the stack of dies due to increased interconnect inductance. However, by utilizing the CV-PTL concept in the PDN design of a 3-layer 3DIC system, the circuit showed considerable improvement in power supply noise and peak-to-peak jitter as compared to the conventional design approach. In addition to signal and power integrity of these signaling schemes, the noise coupling between digital and RF components is also investigated. A simple design for mitigating the coupling of power supply noise in mixed-signal electronics is presented. Currently used methods, such as electromagnetic bandgap structures have been shown to exhibit excellent noise isolation characteristics, and are a popular area of research in this area. However, these structures can pose difficulties for signal integrity. The proposed method extends the previous power transmission line work to address both the power supply noise generation and isolation. Test vehicles using these proposed methods, as well as using an EBG structure were fabricated and tested with regards to power supply noise, jitter, and noise isolation. The proposed methods show significant improvements in almost all performance metrics as compared to EBG. Finally, this dissertation discusses the effect of implementing a power transmission line in a power distribution network composed of a switching regulator and a voltage regulator module. The DC conductor losses of the PTL can not only affect power efficiency of the entire system, but can also affect the proper operation of the linear regulator module when supporting large currents. Consequently, recommendations are made on the design of the PTL to ensure proper operation and efficiency.
694

Hybrid microfluidic cooling and thermal isolation technologies for 3D ICs

Zhang, Yue 08 June 2015 (has links)
A key challenge for three dimensional (3D) integrated circuits (ICs) is thermal management. There are two main thermal challenges in typical 3D ICs. First, in the homogeneous integration with multiple high-power tiers, an effective cooling solution that scales with the number of dice in the stack is needed. Second, in the heterogeneous integration, an effective thermal isolation solution is needed to ‘protect’ the low-power tier from the high-power tier. This research focuses to address these two thermal challenges through hybrid microfluidic cooling and thermal isolation technologies. Within-tier microfluidic cooling is proposed and demonstrated to cool a stack with multiple high-power tiers. Electrical thermal co-analysis is performed to understand the trade-offs between through silicon via (TSV) parasitics and heat sink performance. A TSV-compatible micropin-fin heat sink is designed, fabricated and thermally characterized in a single tier, and benchmarked with a conventional air-cooled heat sink. The designed heat sink has a thermal resistance of 0.269 K·cm2/W at a flow rate of 70 mL/min. High aspect ratios TSVs (18:1) are integrated in the micropin-fins. Within-tier microfluidic cooling is then implemented in 3D stacks to emulate different heating scenarios, such as memory-on-processor and processor-on-processor. Air gap and mechanically flexible interconnects (MFIs) are proposed for the first time to decrease the vertical thermal coupling between high-power (e.g. processor) and low-power tiers (e.g. memory or nanophotonics). A two-tier testbed with the proposed thermal isolation technology is designed, fabricated and tested. Compared with conventional 3D integration approach, thermal isolation technology helps reduce the temperature at a fixed location in the low-tier by 12.9 °C. The resistance of a single MFI is measured to be 46.49 mΩ.
695

IVCon: A GUI-based Tool for Visualizing and Modularizing Crosscutting Concerns

Saigal, Nalin 10 April 2009 (has links)
Code modularization provides benefits throughout the software life cycle; however, the presence of crosscutting concerns (CCCs) in software hinders its complete modularization. This thesis describes IVCon, a GUI-based tool that provides a novel approach to modularization of CCCs. IVCon enables users to create, examine, and modify their code in two different views, the woven view and the unwoven view. The woven view displays program code in colors that indicate which CCCs various code segments implement. The unwoven view displays code in two panels, one showing the core of the program and the other showing all the code implementing each concern in an isolated module. IVCon aims to provide an easy-to-use interface for conveniently creating, examining, and modifying code in, and translating between, the woven and unwoven views.
696

Non-pharmaceutical Intervention Strategies for Pandemic Influenza Outbreaks

Martinez, Dayna Lee 01 January 2012 (has links)
In case of a pandemic influenza outbreak, non-pharmaceutical interventions will likely be the only containment measure at the early stages of the pandemic when vaccines are not available. NPIs also oer an option for decreasing the probability of creating antiviral resistant viruses product of a mass prophylaxis campaign. In countries where there are not enough resources for vaccines and antivirals, NPIs may be the only mitigation actions available. NPIs have been increasingly used in preparedness plans. We can see recommendations and guidelines regarding the use of NPIs in countries, health departments and universities. Also, researchers all around the world have study the impact of NPI's in pandemic influenza outbreaks, most of them using simulation as their modeling tool. Our review of the aforementioned plans and literature shows that there is a lack of consensus in how to implement these interventions. They vary widely in the choice of key parameters such as intervention initiation threshold, duration and compliance. We believe that the lack of uniformity in NPI mitigation strategies arise from the uncertainty in the virus epidemiology and the current lack of scientic knowledge about the complex interactions between virus epidemiology with social behavioral factors and mitigation actions. In this dissertation we addressed this problem by modeling pandemic influenza outbreaks using an agent-based simulation approach. The model incorporates detailed popu- lation demographics and dynamics, variety of mixing groups and their contact processes, infection transmission process, and non-pharmaceutical interventions. Using a statistical experimental design approach we examine the influence of characteristic parameters of virus epidemiology, social behavior, and non-pharmaceutical interventions on various measures of pandemic impact such as total number of infections, deaths and contacts. The experimental design approach also yields the knowledge of the extent of interactions among the above parameters. Using this knowledge we develop eective NPI strategies and demonstrate the efficacy of these strategies on large-scale simulated outbreaks involving three dierent scenarios of virus transmissibility. The results show that signicant improvements in the NPI based pandemic mitigation approaches can be attained by the strategies derived from our methodology.
697

Social isolation enhances calcium signaling and synaptic plasticity in dopamine neurons of the ventral tegmental area

Ramsey, Leslie Anne 20 November 2012 (has links)
Environmental experiences play a critical role in an individualʼs risk of becoming addicted. Positive experiences may mitigate addiction vulnerability, whereas adverse experiences, particularly during adolescence, have been shown to increase addiction risk. Social isolation in rodents is a model system used to study the effects of such experiences, yet its impact on the learning and memory processes that underlie addiction remains elusive. Although social isolation is known to alter the functioning of the dopaminergic system, as well as reward processing and learning, its effect on dopamine (DA) neurons of the ventral tegmental area (VTA) is unknown. The data presented in this dissertation demonstrate that social isolation of rats during a critical period in adolescence (postnatal days 21-42) enhances long-term potentiation (LTP) of N-methyl D-aspartate receptor (NMDAR)-mediated glutamatergic transmission in the VTA. Activation of NMDARs is critical to the generation of DA neuron bursts that encode rewards and reward-predictive cues, and NMDARs are necessary for associative reward learning. The isolation-induced enhancement of NMDAR LTP results from augmentation of metabotropic glutamate receptor (mGluR)-dependent calcium (Ca²⁺) signaling via an increase in inositol 1,4,5-trisphosphate(IP3) sensitivity. Isolation-mediated effects on Ca²⁺ signaling and NMDAR plasticity were not reversed by a subsequent period of resocialization. Furthermore, social isolation during this critical period occludes the effect of repeated amphetamine exposure on mGluR/IP₃-mediated Ca²⁺ signaling and synaptic plasticity. Although corticotropin releasing factor (CRF) further facilitates mGluR/IP3-mediated Ca²⁺ signaling in DA neurons, alterations in CRF receptors are not responsible for the effects of isolation on Ca²⁺ signaling and synaptic plasticity. In addition, the learning of associations between environmental stimuli and drug rewards is acquired more quickly and is more resistant to extinction in isolated animals. Data presented in this dissertation lend support to the theory that enhanced mGluR/IP₃-mediated Ca²⁺ signaling and NMDAR plasticity facilitate the learning and memory of drug-associated stimuli. This dissertation provides the first demonstration of a cellular basis for the critical time window of social isolation during adolescence. NMDAR plasticity in the VTA may thus represent a neural substrate by which early life experiences regulate addiction vulnerability. (Note: Behavioral data were acquired by Mickael Degoulet) / text
698

A Framework for Utilizing Data from Multiple Sensors in Intelligent Mechanical Systems

Krishnamoorthy, Ganesh 25 February 2013 (has links)
Electromechanical Actuators (EMAs) are being increasingly used in many applications. There is a need to augment good design of EMAs with continuous awareness of their operational capability and make them ‘intelligent’ for two key objectives: enhancing performance to address exigent task requirements and to track any changes from their ‘as-built and certified’ state for condition-based maintenance. These objectives are achieved using a decision making philosophy where the human system operator supervises EMA operation using performance criteria and decision surfaces; updated by in-situ measurement of the variables of interest via a suite of diverse sensors. However, operational decisions made on the basis of faulty data could result in unwelcome consequences. With unexpected variations in a sensor’s output from its anticipated values, the challenge is to determine if it indicates a problem in the sensor or the monitored system. In addressing this conundrum, it is also essential to account for the inherent uncertainties present in the values being analyzed. To this end, this dissertation presents the development of a novel Sensor and Process Fault Detection and Isolation (SPFDI) algorithm. This provides a framework to utilize data from all the available sensors in a holistic manner to detect any faults in individual sensors or the system components concurrently. The algorithm uses a Bayesian network to model a system; populated with extensive empirical data. The probabilistic foundations of this method allow for incorporating and propagating uncertainties. The construction of a modular testbed and its Bayesian network are discussed in detail. Several design/ operational criteria have been proposed to aid in the creation of more usable networks in the future. The SPFDI algorithm estimates multiple values for each measurand using different combinations of input variables and probabilistic inferencing. These values are compared against those indicated by the corresponding sensors; a difference between them is indicative of a potential problem. Quantitative indicators to track the condition of different system components and sensors, termed as belief values, are modified after each comparison. The final belief values obtained at the end of an iteration of the algorithm provide a definitive indication of the sources of anomalies in the observed data and can provide guidance to the operator on decisions such as whether or not to use data from a particular sensor for updating existing decision surfaces. The representative examples and experimental results confirm the efficacy of the algorithm in detecting and isolating single as well as multiple sensor faults. The algorithm has also been found to be capable of distinguishing between sensor and system/process faults. Special categories of faults and factors that influence the execution characteristics and quality of results from the algorithm were also explored meticulously and suitable modifications have been suggested to enable the algorithm to continue to function effectively in these situations. To demonstrate the flexibility of the proposed SPFDI algorithm, its potential utilization in four broad classes of applications consisting of complex systems monitored by multiple sensors was also explored in this report. / text
699

Toward roll-to-roll transfer of large-scale graphene for flexible electronics fabrication

Xin, Hao 16 February 2015 (has links)
Graphene is a promising material for flexible electronics due to its extraordinary electrical, mechanical, and optical properties. One of the biggest challenges today is to transfer large-scale graphene sheet to flexible substrates with minimal quality degradation. In this thesis, a bilayer polymer support for graphene transfer is proposed. Liquid PDMS (polydimethylsiloxane) is first coated on graphene to conform to its surface morphology. A flexible plastic substrate is then pressed on PDMS as a durable support. After PDMS is cured, electrochemical delamination is used to separate graphene from the copper foil. Due to the extremely low work of adhesion between graphene and PDMS, the graphene film on PDMS can be further transferred onto silicon wafer or other flexible substrates by simple adhesion. An added benefit of the PDMS layer is its strain isolation effect, which could protect graphene-based devices from breaking under external loads applied on the flexible substrate. The strain isolation effect of PDMS is verified with an analytical model and finite element analysis. The design of a prototype roll-to-roll graphene transfer machine is also presented. / text
700

Identification and characterisation of anti-platelet antibodies in ITP patients

Aghabeigi, N. January 2011 (has links)
No description available.

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